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diff --git a/42149-0.txt b/42149-0.txt new file mode 100644 index 0000000..03dc666 --- /dev/null +++ b/42149-0.txt @@ -0,0 +1,7263 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 42149 *** + +[Transcribers' notes: + +Some tables don't sum to the numbers indicated; no corrections have been +made. All numbers are from the original. + +Minor inconsistencies in hyphenation have been retained. + +Subscripts are represented by underscore and curly braces e.g., CO_{2}. + +Italics are represented by underscores before and after e.g., _italics_. + +Bold is represented by equal signs before and after e.g., =bold=. + +Small caps have been replaced with ALL CAPS.] + + + + + AMERICAN SOCIETY OF CIVIL ENGINEERS + + INSTITUTED 1852 + + TRANSACTIONS + + Paper No. 1155 + + THE NEW YORK TUNNEL EXTENSION OF THE + PENNSYLVANIA RAILROAD. + + THE NORTH RIVER TUNNELS.[A] + + BY B. H. M. HEWETT AND W. L. BROWN, MEMBERS, AM. SOC. C. E. + + [A] Presented at the meeting of June 1st, 1910. + + +INTRODUCTION. + +The section of the Pennsylvania Railroad Tunnel work described in this +paper is that lying between Tenth Avenue, New York City, and the large +shaft built by the Company at Weehawken, N. J., and thus comprises the +crossing of the North or Hudson River, the barrier which has stood for +such a long time between the railroads and their possession of terminal +stations in New York City. The general plan and section, Plate XXVIII, +shows the work included. + +This paper is written from the point of view of those engaged by the +Chief Engineer of the Railroad Company to look after the work of +construction in the field. The history of the undertaking is not +included, the various phases through which many of the designs and plans +passed are not followed, nor are the considerations regarding +foundations under the subaqueous portions of the tunnels and the various +tests made in connection with this subject set out, as all these matters +will be found in other papers on these tunnels. + +This paper only aims to describe, as briefly as possible, the actual +designs which were finally adopted, the actual conditions met on the +ground, and the methods of construction adopted by the contractors. +For easy reference, and to keep the descriptions of work of a similar +character together, the subject will be treated under the four main +headings, viz.: Shafts, Plant, Land Tunnels, and River Tunnels. + + +SHAFTS. + +It is not intended to give much length to the description of the Shafts +or the Land Tunnels, as more interest will probably center in the River +Tunnels. + +The shafts did not form part of the regular tunnel contract, but were +built under contract by the United Engineering and Contracting Company +while the contract plans for the tunnel were being prepared. In this +way, when the tunnel contracts were let, the contractor found the shafts +ready, and he could get at his work at once. + +Two shafts were provided, one on the New York side and one on the New +Jersey side. Their exact situation is shown on Plate XXVIII. They were +placed as near as possible to the point at which the disappearance of +the rock from the tunnels made it necessary to start the shield-driven +portion of the work. + +The details of the shafts will now be described briefly. + +_The Manhattan Shaft._--The Manhattan Shaft is located about 100 ft. +north of the tunnel center; there was nothing noticeable about its +construction. General figures relating to both shafts are given in Table +1. + +_The Weehawken Shaft._--The Weehawken Shaft is shown in Fig. 1. This, as +will be seen from Table 1, was a comparatively large piece of work. The +shaft is over the tunnels, and includes both of them. In the original +design the wall of the shaft was intended to follow in plan the property +line shown in Fig. 2, and merely to extend down to the surface of the +rock, which, as disclosed by the preliminary borings, was here about 15 +ft. below the surface. However, as the excavation proceeded, it was +found that this plan would not do, as the depth to the rock surface +varied greatly, and was often much lower than expected; the rock itself, +moreover, was very treacherous, the cause being that the line of +junction between the triassic sandstone, which is here the country rock, +and the intrusive trap of the Bergen Hill ridge, occurs about one-third +of the length of the shaft from its western end, causing more or less +disintegration of both kinds of rock. Therefore it was decided to line +the shaft with concrete throughout its entire depth, the shape being +changed to a rectangular plan, as shown in the drawings. At the same +time that the shaft was excavated, a length of 40 ft. of tunnels at each +end of it was taken out, also on account of the treacherous nature of +the ground, thus avoiding risk of injury to the shaft when the tunnel +contractors commenced work. There was much trouble with floods during +the fall of 1903, and numerous heavy falls of ground occurred, in spite +of extreme care and much heavy timbering. The greatest care was also +taken in placing the concrete lining, and the framing to support the +forms was carefully designed and of heavy construction; the forms were +of first-class workmanship, and great care was taken to keep them true +to line. A smooth surface was given to the concrete by placing a 3-in. +layer of mortar at the front of the walls and tamping this dry facing +mixture well down with the rest of the concrete. The east and west walls +act as retaining walls, while those on the north and south are facing +walls, and are tied to the rock with steel rods embedded and grouted +into the rock and into the concrete. Ample drainage for water at the +back of the wall was provided by upright, open-joint, vitrified drains +at frequent intervals, with dry-laid stone drains leading to them from +all wet spots in the ground. A general view of the finished work is +shown in Fig. 1, Plate XXIX, and Table 1 gives the most important dates +and figures relating to this shaft. + +TABLE 1.--PARTICULARS OF SHAFTS ON THE NORTH RIVER TUNNELS OF THE +PENNSYLVANIA RAILROAD TUNNELS INTO NEW YORK CITY. + + +===========+=====+======+======+==========+========+===========+========+ + |Location. |Depth| Width|Length|Excavation|Concrete| Date| Date| + | | in| in| in|(including|in cubic|commenced.|finished.| + | |feet.| feet.| feet.| drifts),| yards.| | | + | | | | | in cubic| | | | + | | | | | yards. | | | | + +-----------+-----+------+------+----------+--------+----------+---------+ + |Manhattan: | 55| 22| 32| 2,010| 209|June 10th,| December| + |11th Avenue| | | | | | 1903.| 11th,| + |and 32d | | | | | | | 1903.| + |Street. | | | | | | | | + | | | | | | | | | + |Weehawken: | 76| At| At| 55,315| 9,810|June 11th,|September| + |Baldwin | |bottom|bottom| | | 1903.|1st, | + |Avenue. | |56, at|115.75| | | |1904. | + | | | top|at top| | | | | + | | | 100.| 154.| | | | | + |===========+=====+======+======+==========+========+==========+=========+ + + +==========+====================+=============+============+===========+ + |Location. |Ground met: |Lined with: | Cost to | Cost per | + | | | | Railroad |cubic foot.| + | | | | Company. | | + +----------+--------------------+-------------+------------+-----------+ + |Manhattan:|Top 13 ft. filled; |Concrete | $12,943.75 | $0.335 | + |11th |red mica schist and |reinforced | | | + |Avenue and|granite. |with steel | | | + |32d | |beams down to| | | + |Street. | |rock. | | | + | | | | | | + |Weehawken:|Top 6 ft. filled, 30|Concrete with| 166,162,98 | 0.337 | + |Baldwin |ft. sand and |steel | | | + |Avenue. |hardpan, decomposed |tie-rods in | | | + | |rock (trap and |rock. | | | + | |sandstone) below. | | | | + +==========+====================+=============+============+===========+ + +[Illustration: FINAL DESIGN OF WEEHAWKEN SHAFT PLAN LONGITUDINAL SECTION +TRANSVERSE SECTION FIG. 1.] + +After the tunnel work was finished, both shafts were provided with +stairs leading to the surface, a protective head-house was placed over +the New York Shaft, and a reinforced concrete fence, 8 ft. high, was +built around the Weehawken Shaft on the Company's property line, that +is, following the outline of the shaft as originally designed. + + +PLANT. + +Working Sites. + +Before beginning a description of the tunnel work, it may be well to set +out in some detail the arrangements made on the surface for conducting +the work underground. + +All the work was carried on from two shafts, one at Eleventh Avenue and +32d Street, New York City--called the Manhattan Shaft--and one at +Baldwin Avenue, Weehawken, N. J.--called the Weehawken Shaft. + +[Illustration: WEEHAWKEN SHAFT. EXCAVATION FIG. 2.] + +The characteristics of the two sites were radically different, and +called for different methods of handling the transportation problem. The +shaft site at Manhattan is shown on Plate XXX. It will be seen that +there was not much room, in fact, the site was too cramped for comfort; +the total area, including the space occupied by the old foundry, used +for power-houses, offices, etc., was about 3,250 sq. yd. This made it +necessary to have two stages, one on the ground level for handling +materials into the yard, and an overhead gantry on which the excavated +materials were handled off the premises. The yard at Weehawken was much +larger; it is also shown on Plate XXX. Its area was about 15,400 sq. yd. +in the yard proper, and there was an additional space of about 750 sq. +yd. alongside the wharf at the "North Slip," on the river front, +connected with the main portion of the yard by an overhead trestle. + +All the cars at Manhattan were moved by hand, but at Weehawken two +electric locomotives with overhead transmission were used. + + +Power-House Plant. + +At the Manhattan Shaft the power-house plant was installed on the ground +floor of the old foundry building which occupied the north side of the +leased area. This was a brick building, quite old, and in rather a +tumble-down condition when the Company took possession, and in +consequence it required quite a good deal of repair and strengthening +work. The first floor of the building was used by the contractor as +offices, men's quarters, doctor's offices, and so on, and on the next +one above, which was the top floor, were the offices occupied by the +Railroad Company's field engineering staff. + +On the Weehawken side, the plant was housed in a wooden-frame, +single-story structure, covered with corrugated iron. It was rectangular +in plan, measuring 80 by 130 ft. + +At both sides of the river the engines were bedded on solid concrete on +a rock foundation. + +The installation of the plant on the Manhattan side occupied from May, +1904, to April, 1905, and on the Weehawken side from September, 1904, to +April, 1905. Air pressure was on the tunnels at the New York side on +June 25th, 1905, and on the Weehawken side on the 29th of the same +month. + +[Illustration: PLATE XXIX. TRANS. AM. SOC. CIV. ENGRS. VOL. LXVIII, No. +1155. HEWETT AND BROWN ON PENNSYLVANIA R. R. TUNNELS: NORTH RIVER +TUNNELS. FIG. 1. FIG. 2.] + +The plants contained in the two power-houses were almost identical, +there being only slight differences in the details of arrangement due to +local conditions. A list of the main items of the plant at one +power-house is shown in Table 2. + +TABLE 2.--PLANT AT ONE POWER-HOUSE. + + +======+======================================================+========+ + |No. of| | | + |items.|Description of item. | Cost.| + |------+------------------------------------------------------+--------| + |Three |500-h.p. water-tube Sterling boilers | $15,186| + |Two |Feed pumps, George F. Blake Manufacturing Company | 740| + |One |Henry R. Worthington surface condenser | 6,539| + |Two |Electrically-driven circulating pumps on river front | 5,961| + |Three |Low-pressure compressors, Ingersoll-Sergeant Drill | 33,780| + | |Company | | + |One |High-pressure compressor, Ingersoll-Sergeant Drill | 6,665| + | |Company | | + |Three |Hydraulic power pumps, George F. Blake Manufacturing | 3,075| + | |Company | | + |Two |General Electric Company's generators coupled to Ball | 7,626| + | |and Wood engines | | + |------+------------------------------------------------------+--------| + | |Total cost of main items of plant | $79,572| + |------+------------------------------------------------------+--------| + | SUMMARY OF COST OF ONE PLANT. + |-------------------------------------------------------------+--------+ + |Total cost of main items of plant | $79,572| + | | | + |Cost of four shields (including installation, demolition, | 103,560| + |large additions and renewals, piping, pumps, etc.) | | + | | | + |Cost of piping, connections, drills, derricks, installation | 101,818| + |of offices and all miscellaneous plant | | + | | | + |Cost of installation, including preparation of site | 39,534| + |-------------------------------------------------------------+--------| + |Total prime cost of one power-house plant |$324,484| + |=============================================================+========| + +The following is a short description of each item of plant in Table 2: + +_Boilers._--At each shaft there were three 500-h.p., water-tube boilers, +Class F (made by Sterling and Company, Chicago, Ill.). They had +independent steel stacks, 54 in. in diameter and 100 ft. above grate +level; each had 5,000 sq. ft. of heating surface and 116 sq. ft. of +grate area. The firing was by hand, and there were shaking grates and +four doors to each furnace. Under normal conditions of work, two boilers +at each plant were able to supply all the steam required. The average +working pressure of the steam was 135 lb. per sq. in. + +The steam piping system was on the loop or by-pass plan. The diameter of +the pipes varied from 14 in. in the main header to 10 in. in the body of +the loop. The diameter of the exhaust steam main increased from 8 in. at +the remote machines to 20 in., and then to 30 in., at the steam +separator, which in turn was connected with the condensers. A pipe with +an automatic relief valve from the exhaust to the atmosphere was used +when the condensers were shut down. All piping was of the standard, +flanged extra-heavy type, with bronze-seated gate-valves on the +principal lines, and globe-valves on some of the auxiliary ones. There +was an 8-in. water leg on the main header fitted with a Mason-Kelly +trap, and other smaller water traps were set at suitable intervals. + +Each boiler was fitted with safety valves, and there were automatic +release valves on the high-and low-pressure cylinders of each +compressor, as well as on each air receiver. + +Buckwheat coal was used, and was delivered to the bins on the Manhattan +side by teams and on the Weehawken side by railroad cars or in barges, +whence it was taken to the power-house by 2-ft. gauge cars. An average +of 20 tons of coal in each 24 hours was used by each plant. + +The water was taken directly from the public service supply main. The +daily quantity used was approximately 4,000 gal. for boiler purposes and +4,400 gal. for general plant use. Wooden overhead tanks having a +capacity of 14,000 gal. at each plant served as a 12-hour emergency +supply. + +_Feed Pumps._--There were two feed pumps at each plant. They had a +capacity of 700 cu. ft. per min., free discharge. The plungers were +double, of 6-in. diameter, and 10-in. stroke, the steam cylinders were +of 10-in. diameter and 10-in. stroke. An injector of the "Metropolitan +Double-Tube" type, with a capacity of 700 cu. ft. per min., was fitted +to each boiler for use in emergencies. + +The feed-water heater was a "No. 9 Cochrane," guaranteed to heat 45,000 +lb. of water per hour, and had a total capacity of 85.7 cu. ft. It was +heated by the exhaust steam from the non-condensing auxiliary plant. + +_Condenser Plant._--There were two surface condensers at each plant. +Each had a cooling surface sufficient to condense 22,500 lb. of steam +per hour, with water at a temperature of 70° Fahr. and barometer at 30 +in., maintaining a vacuum of 26 in. in the condenser. Each was fitted +with a Blake, horizontal, direct-acting, vacuum pump. + +_Circulating-Water Pumps._--Two circulating-water pumps, supplying salt +water directly from the Hudson River, were placed on the wharf. They +were 8-in. centrifugal pumps, each driven by a 36-h.p., General Electric +Company's direct-current motor (220 volts and 610 rev. per min.), the +current being supplied from the contractor's power-house generators. The +pumps were run alternately 24 hours each at a time. Those on the +Manhattan side were 1,300 ft. from the power-house, and delivered their +water through a 16-in. pipe; those on the Weehawken side were 450 ft. +away, and delivered through a 14-in. pipe. There was also a direct +connection with the city mains, in case of an accident to the salt-water +pumps. + +_Low-Pressure Compressors._--At each plant there were three low-pressure +compressors. These were for the supply of compressed air to the working +chambers of the subaqueous shield-driven tunnels. They were also used on +occasions to supply compressed air to the cylinders of the high-pressure +compressors, thus largely increasing the capacity of the latter when +hard pressed by an unusual call on account of heavy drilling work in the +rock tunnels. They were of a new design, of duplex Corliss type, having +cross-compound steam cylinders, designed to operate condensing, but +capable of working non-condensing; the air cylinders were simple duplex. +The steam cylinder valves were of the Corliss release type, with vacuum +dash-pots. The valves in the air cylinders were mechanically-operated +piston valves, with end inlet and discharge. The engines used steam at +135 lb. pressure. The high-and low-pressure steam cylinders were 14 in. +and 30 in. in diameter, respectively, with a stroke of 36 in. and a +maximum speed of 135 rev. per min. The two air cylinders were 23½ in. +in diameter, and had a combined capacity of 35.1 cu. ft. of free air per +revolution, and, when running at 125 rev. per min., each machine had an +actual capacity of 4,389 cu. ft. of free air per min., or 263,340 cu. +ft. per hour. The air cylinders were covered by water-jackets through +which salt water from the circulating pumps flowed. A gauge pressure of +50 lb. of air could be obtained. + +Each compressor was fitted with an automatic speed and air-pressure +regulator, designed to vary the cut-off according to the volume of air +required, and was provided with an after-cooler fitted with tinned-brass +tube and eight Tobin-bronze tube-plates having 809 sq. ft. of cooling +surface; each one was capable of reducing the temperature of the air +delivered by it to within 10° Fahr. of the temperature of the cooling +water when its compressor was operated at its fullest capacity. From the +after-cooler the air passed into a vertical receiver, 4 ft. 6 in. in +diameter and 12 ft. high, there being one such receiver for each +compressor. The receivers were tested to a pressure of 100 lb. per sq. +in. The after-coolers were provided with traps to collect precipitated +moisture and oil. The coolers and receivers were fitted with safety +valves set to blow off at 1 lb. above the working pressure. The air +supply was taken from without, and above the power-house roof, but in +very cold weather it could be taken from within doors. + +_High-Pressure Compressors._--There was one high-pressure compressor at +each plant. Each consisted of two duplex air cylinders fitted to a +cross-compound, Corliss-Bass, steam engine. The two steam cylinders were +14 and 26 in. in diameter, respectively, and the air cylinders were +14¼ in. in diameter and had a 36-in. stroke. The air cylinder was +water-jacketed with salt water supplied from the circulating water +pumps. + +The capacity was about 1,100 cu. ft. of free air per min. when running +at 85 rev. per min. and using intake air at normal pressure, but, when +receiving air from the low-pressure compressors at a pressure of 30 lb. +per sq. in., the capacity was 3,305 cu. ft. of free air per min.; +receiving air at 50 lb. per sq. in., the capacity would have been 4,847 +cu. ft. of free air per min. This latter arrangement, however, called +for more air than the low-pressure compressors could deliver. With the +low-pressure compressor running at 125 rev. per min. (its maximum +speed), it could furnish enough air at 43.8 lb. per sq. in. to supply +the high-pressure compressor running at 85 rev. per min. (its maximum +speed); and, with the high-pressure compressor delivering compressed air +at 150 lb., the combined capacity of the arrangement would have been +4,389 cu. ft. of free air per min. + +The air passed through a receiver, 4 ft. 6 in. in diameter and 12 ft. +high, tested under a water pressure of 225 lb. per sq. in., before being +sent through the distributing pipes. + +_Hydraulic Power Pumps._--At each power-house there were three hydraulic +power pumps to operate the tunneling shields. One pump was used for each +tunnel, leaving the third as a stand-by. The duplex steam cylinders were +15 in. in diameter, with a 10-in. stroke; the duplex water rams were +2-1/8 in. in diameter with a 10-in. stroke. The pumps were designed to +work up to 6,000 lb. per sq. in., but the usual working pressure was +about 4,500 lb. The piping, which was extra heavy hydraulic, was +connected by heavy cast-steel screw couplings having a hexagonal +cross-section in the middle to enable tightening to be done with a bolt +wrench. The piping was designed to withstand a pressure of 5,500 lb. per +sq. in. + +_Electric Generators._--At each plant there were two electric generators +supplying direct current for both lighting and power, at 240 volts, +through a two-wire system of mains. They were of Type M-P, Class 6, 100 +kw., 400 amperes, 250 rev. per min., 240 volts no load and 250 volts +full load. They were connected direct to 10 by 20 by 14-in., +center-crank, tandem-compound, engines of 150 h.p. at 250 rev. per min. +A switch-board, with all the necessary fuses, switches, and meters, was +provided at each plant. + +_Lubrication._--In the lubricating system three distinct systems were +used, each requiring its own special grade of oil. + +The journals and bearings were lubricated with ordinary engine oil by a +gravity system; the oil after use passed through a "White Star" filter, +and was pumped into a tank about 15 ft. above the engine-room floor. + +The low-pressure air cylinders were lubricated with "High Test" oil, +having a flash point of 600° Fahr. The oil was forced from a receiving +tank into an elevated tank by high-pressure air. When the tank was full +the high-pressure air was turned off and the low-pressure air was turned +on, in this way the air pressure in the oil tank equalled that in the +air cylinder being lubricated, thus allowing a perfect gravity system to +exist. + +The steam cylinders and the high-pressure air cylinders were fed with +oil from hand-fed automatic lubricators made by the Detroit Lubrication +Company, Detroit, Mich. + +"Steam Cylinder" oil was used for the steam cylinders and "High Test" +oil (the same as used for the low-pressure air cylinders) for the +high-pressure air cylinders. The air cylinder and steam cylinder +lubricators were of the same kind, except that no condensers were +necessary. The steam cylinder and engine oil was caught on drip pans, +and, after being filtered, was used again as engine oil in the bearings. +The oil from the air cylinders was not saved, nor was that from the +steam cylinders caught at the separator. + +_Cost of Operating the Power-House Plants._--In order to give an idea of +the general cost of running these plants, Tables 3 and 4 are given as +typical of the force employed and the general supplies needed for a +24-hour run of one plant. Table 3 gives a typical run during the period +of driving the shields, and Table 4 is typical of the period of concrete +construction. In the latter case the tunnels were under normal air +pressure. Before the junction of the shields, both plants were running +continuously; after the junction, but while the tunnels were still under +compressed air, only one power-house plant was operated. + +TABLE 3.--COST OF OPERATING ONE POWER-HOUSE FOR 24 HOURS DURING +EXCAVATION AND METAL LINING. + + ===+===================+====================+============= + No.| Labor. | Rate per day. | Amount. + ---+-------------------+--------------------+------------- + 6 |Engineers | $3.00 | $18.00 + 6 |Firemen | 2.50 | 15.00 + 2 |Oilers | 2.00 | 4.00 + 2 |Laborers | 2.00 | 4.00 + 4 |Pumpmen | 2.75 | 11.00 + 2 |Electricians | 3.50 | 7.00 + 1 |Helper | 3.00 | 3.00 + ---+-------------------+--------------------+------------- + Total per day | $62.00 + --------------------------------------------+------------- + Total for 30 days | $1,860.00 + --------------------------------------------+------------- + Supplies. + -----------------------+--------------------+------------- + Coal (14 tons per day) | $3.25 | $45.50 + Water | 7.00 | 7.00 + Oil (4 gal. per day) | 0.50 | 2.00 + Waste (4 lb. per day) | 0.07 | 0.28 + Other supplies | 1.00 | 1.00 + -----------------------+--------------------+------------- + Total per day | $55.78 + --------------------------------------------+------------- + Total for 30 days | $1,673.00 + --------------------------------------------+------------- + Total cost of labor and supplies for 30 days| $3,533.00 + ============================================+============= + +_Stone-Crusher Plant._--A short description of the stone-crusher plant +will be given, as it played an important part in the economy of the +concrete work. In order to provide crushed stone for the concrete, the +contractor bought (from the contractor who built the Bergen Hill +Tunnels) the pile of trap rock excavated from these tunnels, which had +been dumped on the piece of waste ground to the north of Baldwin Avenue, +Weehawken, N. J. + +The general layout of the plant is shown on Plate XXX. It consisted of a +No. 6 and a No. 8 Austin crusher, driven by an Amex, single-cylinder, +horizontal, steam engine of 120 h.p., and was capable of crushing about +225 cu. yd. of stone per 10-hour day. The crushers and conveyors were +driven from a countershaft, in turn driven from the engine by an 18-in. +belt. + +TABLE 4.--COST OF OPERATING THE ONE PLANT FOR 24 HOURS DURING CONCRETE +LINING. + + ===+===================+====================+============= + No.| Labor. | Rate per day. | Amount. + ---+-------------------+--------------------+------------- + 2 |Engineers | $3.00 | $6.00 + 2 |Firemen | 2.50 | 5.00 + 2 |Pumpmen | 3.00 | 6.00 + 1 |Foreman Electrician| 6.00 | 6.00 + 1 |Electrician | 3.00 | 3.00 + 1 |Laborer | 2.00 | 2.00 + ---+-------------------+--------------------+------------- + Total per day | $28.00 + --------------------------------------------+------------- + Total for 30 days | $840.00 + --------------------------------------------+------------- + Supplies. + -----------------------+--------------------+------------- + Coal (14 tons per day) | $3.15 | $44.10 + Oil (4 gal. per day) | 0.50 | 2.00 + Water | 13.00 | 13.00 + Other supplies | 2.00 | 2.00 + -----------------------+--------------------+------------- + Total per day | $61.10 + --------------------------------------------+------------- + Total for 30 days | $1,833.00 + --------------------------------------------+------------- + Total cost of labor and supplies for 30 days| $2,673.00 + ============================================+============= + +The process of crushing was as follows: The stone from the pile was +loaded by hand into scale-boxes which were lifted by two derricks into +the chute above the No. 6 crusher. One derrick had a 34-ft. mast and a +56-ft. boom, and was worked by a Lidgerwood steam hoister; the other had +a 23-ft. mast and a 45-ft. boom, and was worked by a "General Electric" +hoist. All the stone passed first through the No. 6 crusher, after which +it was lifted by a bucket conveyor to a screen, placed about 60 ft. +higher than and above the stone bin. The screen was a steel chute +pierced by 2½-in. circular holes, and was on a slope of about 45°; in +order to prevent the screen from choking, it was necessary to have two +men continually scraping the stone over it with hoes. All the stone +passing the screen was discharged into a bin below with a capacity of +about 220 cu. yd. The stone not passing the screen passed down a +diagonal chute to a No. 8 crusher, from which, after crushing, it was +carried back by a second bucket conveyor to the bin, into which it was +dumped without passing a screen. The No. 8 crusher was arranged so that +it could, when necessary, receive stone direct from the stone pile. The +cars in which the stone was removed could be run under the bin and +filled by opening a sliding door in the bottom of the bin. A track was +laid from the bin to connect with the contractor's surface railway in +the Weehawken Shaft yard, and on this track the stone could be +transported either to the Weehawken Shaft direct, for use on that side +of the river, or to the wharf, where it could be dumped into scows for +transportation to New York. + +The cars used were 3-cu. yd. side-dump, with flap-doors, and were hauled +by two steam Dinky locomotives. + +The average force employed was: + + 1 foreman @ $3.00 per day. Supervising. + 24 laborers " 1.75 " " Loading scale-boxes for derricks. + 4 laborers " 1.75 " " Feeding crushers. + 2 laborers " 1.75 " " Watching screens to prevent clogging. + 1 engineer " 4.00 " " Driving steam engine. + 2 engineers " 3.50 " " On the derricks. + 1 night watchman. Watching the plant at night. + +Owing to the constant break-down of machinery, chutes, etc., inseparable +from stone-crushing work, there was always at work a repair gang +consisting of either three carpenters or three machinists, according to +the nature of the break-down. + +The approximate cost of the plant was: + + Machinery $5,850 + Lumber 3,305 + Erection labor 3,999 + ------ + Total $13,154 + +The cost of the crushed stone at Weehawken amounted to about $0.91 per +cu. yd., and was made up as follows: + + Cost of stone $0.22 + Labor in operation of plant 0.31 + Plant supplies 0.11 + [B]Plant depreciation 0.27 + ----- + Total $0.91 + +[B] Assuming that the scrap value of derricks and engines is one-half +the cost, crushers one-third the cost, and other items nothing. + +The crushed stone at the Manhattan Shaft cost about $1.04 per cu. yd., +the difference of $0.13 from the Weehawken cost being made up of the +cost of transfer across the river, $0.08, and transport from the dock to +the shaft, $0.05. + +_Miscellaneous Plant._--The various pieces of plant used directly in the +construction work, such as derricks, hauling engines, pumps, concrete +mixers, and forms, will be found described or at least mentioned in +connection with the methods used in construction. + +The tunneling shields, however, will be described now, as much of the +explanation of the shield-driven work will not be clear unless preceded +by a good idea of their design. + + +Tunneling Shields. + +During the period in which the original contract drawings were being +made, namely, in the latter part of 1903 and the early part of 1904, +considerable attention was given to working out detailed studies for a +type of shield which would be suitable for dealing with the various +kinds of ground through which the shield-driven tunnels had to pass. +This was done in order that, when the contract was let, the engineer's +ideas of the requirements of the shields should be thoroughly +crystallized, and so that the contractor might take advantage of this +long-thought-out design, instead of being under the necessity of placing +a hurried order for a piece of plant on which so much of the safety as +well as of the speed of his work depended. Eventually, the contractor +took over these designs as they stood, with certain minor modifications, +and the shields as built and worked gave entire satisfaction. The chief +points held in view were ample strength, easy access to the working face +combined with ease and quickness of closing the diaphragm, and general +simplicity. A clear idea of the main features of the design can be +gathered from Fig. 3 and Plate XXXI. + +[A]The interior diameter of the skin was 2 in. greater than the +external diameter of the metal lining of the tunnel, which was 23 ft. +The skin was made up of three thicknesses of steel plate, a ¾-in. +plate outside and inside, with a 5/8-in. plate between; thus the +external diameter of the skin was 23 ft. 6¼ in. The length over all +(exclusive of the hood, to be described later) was 15 ft. 11-7/16 in. +The maximum overlap of the skin over the erected metal lining was 6 ft. +4½ in., and the minimum overlap, 2 ft. + +There were no inside or outside cover-plates, the joints of the various +pieces of skin plates being butt-joints covered by the overlap of +adjoining plates. All riveting was flush, both inside and outside. The +whole circumference of each skin plate was made up of eight pieces, each +of which extended the entire length of the shield, the only +circumferential joint on the outside being at the junction of the +removable cutting edge (or of the hood when the latter was in position) +with the shield proper. + +Forward of the back ends of the jacks, the shield was stiffened by an +annular girder supporting the skin, and in the space between the +stiffeners of which were set the 24 propelling rams used to shove the +shield ahead by pressure exerted on the last erected ring of metal +lining, as shown on Plate XXXI. + +To assist in taking the thrust of these rams, gusset-plates were placed +against the end of each ram cylinder, and were carried forward to form +level brackets supporting the cast-steel cutting-edge segments. The +stiffening gussets, between which were placed the rams, were also +carried forward as level brackets, for the same purpose. The cast-steel +segmental cutting edge was attached to the front of the last mentioned +plates. + +The interior structural framing consisted of two floors and three +vertical partitions, giving nine openings or pockets for access to the +face; these pockets were 2 ft. 7 in. wide, the height varying from 2 ft. +2 in. to 3 ft. 4 in., according to their location. The openings were +provided with pivoted segmental doors, which were adopted because they +could be shut without having to displace any ground which might be +flowing into the tunnel, and while open their own weight tended to close +them, being held from doing so by a simple catch. + +[Illustration: PROPOSED SHIELD FOR SUBAQUEOUS TUNNELING GENERAL +ELEVATION FIG. 3.] + +For passing through the varied assortment of ground before entering on +the true sub-river silt, it was decided to adopt the forward detachable +extension, or hood, which has so often proved its worth in ground +needing timber for its support, as shown in Fig. 2, Plate XXIX. This +hood extended 2 ft. 1 in. beyond the cutting edge, and from the top down +to the level of the upper platform. Additional pieces were provided by +which the hood might have been brought down as far as the lower +platform, but they were not used. Special trapezoidal steel castings +formed the junction between the hood and the cutting edge. The hood was +in nine sections, built up of two ¾-in. and one 5/8-in. skin plates, +as in the main body of the skin, and was supported by bracket plates +attached to the forward ends of the ram chambers. The hoods were bolted +in place, and were removed and replaced by regular cutting-edge steel +castings after the shields had passed the river lines. + +The floors of the two platforms, of which there were eight, formed by +the division of the platforms by the upright framing, could be extended +forward 2 ft. 9 in. in front of the cutting edge, or 8 in. in front of +the hood. This motion was given by hydraulic jacks. The sliding platform +could hold a load of 7,900 lb. per sq. ft., which was equal to the +maximum head of ground and water combined. The uses of these platforms +will be described under the heading "Construction." The weight of the +structural portion of each shield was about 135 tons. + +The remainder of the shield was the hydraulic part, which provided its +motive force and gave the power to the segment erector. The hydraulic +fittings weighed about 58 tons per shield, so that the total weight of +each shield was about 193 tons. The hydraulic apparatus was designed for +a maximum pressure of 5,000 lb. per sq. in., a minimum pressure of 2,000 +lb., and a test pressure of 6,000 lb. The actual average pressure used +was about 3,500 lb. per sq. in. + +There were 24 shoving rams, with a diameter of 8½ in. and stroke of +38 in. The main ram was single-acting. The packings could be tightened +up from the outside without removing the ram, a thing which is of the +greatest convenience, and cannot be done with the differential plunger +type. Some of the chief figures relating to the shield rams, with a +water pressure of 5,000 lb. per sq. in., are: + + Forward force of one ram 275,000 lb. + Forward force of 24 rams (all) 6,600,000 " + Forward force of 24 rams 3,300 tons of 2,000 lb. + Equivalent pressure per square inch of face 105 lb. + Equivalent pressure per square foot of face 15,200 " + Pull-back force of one ram 26,400 " + Pull-back pressure on full area of ram 480 " per sq. in. + +The rams developed a tendency to bend, under the severe test of shoving +the shield all closed, or nearly so, through the river silt, and it is +probable that it would have been better to make the pistons 10 in. in +diameter instead of 8½ in. + +Each sliding platform was actuated by two single-acting rams, 3½ in. +in diameter and having a stroke of 2 ft. 9 in. The rams were attached to +the rear face of the shield diaphragm inside the box floors, and the +cylinders were movable, sliding freely on bearings in the floor. The +front ends of the cylinders were fixed to the front ends of the sliding +platforms. The cylinder thus supported the front end of the sliding +platform, and was designed to carry its half of the load on the +platform. Some of the leading figures in connection with the platform +rams, at a working pressure of 5,000 lb. per sq. in., are: + + Forward force of each pair of rams (in each platform) 96,000 lb. + Total area of nose of sliding platform 1,060 sq. in. + Maximum reaction per square inch on nose 90 lb. + Maximum reaction per square foot on nose 13,040 " + +Each shield was fitted with a single erector mounted on the rear of the +diaphragm. The erector consisted of a box-shaped frame mounted on a +central shaft revolving on bearings attached to the shield. Inside of +this frame there was a differential hydraulic plunger, 4 in. and 3 in. +in diameter and of 48-in. stroke. To the plunger head were attached two +channels sliding inside the box frame, and to the projecting ends of +these the grip was attached. At the opposite end of the box frame a +counterweight was attached which balanced about 700 lb. of the tunnel +segment at 11 ft. radius. + +The erector was revolved by two single-acting rams fixed horizontally to +the back of the shield above the erector pivot through double chains and +chain wheels keyed to the erector shaft. + +The principal figures connected with the erector, assuming a water +pressure of 5,000 lb. per sq. in., are: + + Weight of heaviest tunnel segment 2,584 lb. + Weight of erector plunger and grip 616 " + Total weight to be handled by the erector ram 3,200 " + Total force in erector ram moving from center of shield 35,000 " + Total force in erector ram moving toward center of shield 27,500 " + Weight at 11-ft. radius which is balanced by counterweight 700 " + Maximum net weight at 11-ft. radius to be handled by + turning rams 1,884 " + Total force of each rotating ram, at 5,000 lb. per sq. in. 80,000 " + Load at 11-ft. radius, equivalent to above 3,780 " + +When the shield was designed, a grip was also designed by which the +erector could handle segments without any special lugs being cast on +them. A bolt was passed through two opposite bolt holes in the +circumferential flanges of a plate. The grip jaws closed over this bolt +and locked themselves. The projecting fixed ends of the grip were for +taking the direct thrust on the grip caused by the erector ram when +placing a segment. + +It happened, however, that there was delay in delivering these grips, +and, when the shield was ready to start, and the grip was not +forthcoming, Mr. Patrick Fitzgerald, the Contractor's Superintendent, +overcame this trouble by having another grip made. + +In this design, also, a self-catching bolt is placed through the segment +and the grip catches the bolt. In simplicity and effectiveness in +working, this new design eventually proved a decided advance on the +original one, and, as a result, all the shields were fitted with the new +grip, and the original design was discarded. + +The great drawback to the original grip was that the plate swung on the +lifting bolt, and thus brought a great strain on the bolt when held +rigidly at right angles to the erector arm. The original design was able +to handle both _A_ and _B_ segments, and key segments, without +alteration; in the new design, an auxiliary head had to be swung into +position to handle the key, but this objection did not amount to a +practical drawback. + +The operating floor from which the shield was controlled, and at which +the valves were situated, was placed above the rams which rotate the +erector, and formed a protection for them. The control of the shield +rams was divided into four groups: the seven lower rams constituted one +group, the upper five, another, and the six remaining on each side, the +other two. Each group was controlled by its own stop and release valve. +Individual rams were controlled by stop-cocks. + +The control of the sliding platform rams was divided into two groups, of +which all the rams on the upper floor made one, and all those in the +lower floor, the other; here, again, each group had its own stop and +release valve, and individual platforms were controlled by stop-cocks +arranged in blocks from which the pipes were carried to the rams. + +The in-and-out movements of the erector ram were controlled by a +two-spindle, balanced, stop and release valve, controlled by a +hand-wheel. The erector rotating rams were controlled by a similar +valve, with four spindles, also operated by a single hand-wheel. Both +wheels were placed inside the top shield pockets, and within easy reach +of the operating platform. + +The hydraulic pressure was brought through the tunnel by a 2-in. +hydraulic pipe. Connection with the shield was made by a flexible copper +pipe, the 2-in. line being extended as the shield advanced. + + +LAND TUNNELS. + +General. + +The following is a brief account of the main features of the "Land +Tunnel" work, by which is meant all the part of the structure built +without using tunneling shields. + +The Land Tunnels consist of about 977 ft. of double tunnel on the New +York side and 230 ft. on the New Jersey side, or a total of 1,207 lin. +ft. of double tunnel. + +The general design of the cross-section consists of a semi-circular +arch, vertical side-walls and a flat invert. The tunnel is adapted for +two lines of track, each being contained in its compartment or tunnel. +The span of the arch is wider than is absolutely necessary to take the +rolling stock, and the extra space is utilized by the provision of a +sidewalk or "bench" forming by its upper surface a gangway, out of the +way of traffic, for persons walking in the tunnels, and embedded in its +mass are a number of vitrified earthenware ducts, for high-and +low-tension electric cables. The provision of this bench enables its +vertical wall to be brought much nearer to the side of the rolling stock +than is usually possible, thus minimizing the effects of a derailment or +other accident. Refuge niches for trackmen, and ladders to the top of +the bench are provided at frequent intervals. In cases where a narrow +street limits the width of the structure, as on the New York side, the +two tunnels are separated by a medial wall of masonry, thus involving +excavation over the entire width of both tunnels, and in such case the +tunnels are spoken of as "Twin Tunnels"; where the exigencies of width +are not so severe, the two tunnels are entirely distinct, and are +separated by a wall of rock. This type is found on the Weehawken side. +The arches are of brick, the remainder of the tunnel lining being of +concrete. + + +New York Land Tunnels. + +The work on the Land Tunnels on the Manhattan side was carried on from +the shaft at 11th Avenue and 32d Street. + +The plans and designs for these tunnels are shown on Plate XXXII. In +this short length of about 977 ft. there are no less than nine different +kinds of cross-section. The reason for these changes is the fact that +the two lines of track are here not straight and parallel to the center +line between the tunnels, but are curved, although symmetrical about +this center line. The various changes of section are to enable the +tunnels to be built in straight lengths, thus avoiding the disadvantages +attending the use of curved forms, and at the same time minimizing the +quantity of excavation, an item which accounts for from 60 to 70% of the +total cost of tunnels of this type. Of course, there are corresponding +and obvious disadvantages in the adoption of many short lengths of +different cross-sections, and these disadvantages were well brought out +in the course of the work; on the whole, however, they may be said to +have justified their adoption. These New York Land Tunnels were divided +into three contracts, viz.: From Station 190 + 15 (the Portal to the +open work of the Terminal Station at the east side of Tenth Avenue, New +York City) to Station 197 + 60, called "Section Gy-East." The next +contract, called "Section Gy-West Supplementary," extended from Station +197 + 60 to Station 199 + 20, which is the east side of Eleventh Avenue. +The third contract was called "Section Gy-West," and extended from +Station 199 + 20 to Station 231 + 78 (the dividing line between the +States of New York and New Jersey). Thus, for nearly all its length, +this contract consists of shield-driven tunnel. The portion between +Stations 199 + 20 and 199 + 91.5, however, was of the Land Tunnel type, +and therefore will be included here. A fourth contract extended from +Station 231 + 78 to the Weehawken Shaft at Station 263 + 50, and of this +all but 230 ft. was of the shield-driven type, only the portion next to +the Weehawken Shaft being of the Land Tunnel type. + +The four contracts were let to one contractor (The O'Rourke Engineering +Construction Company), and the work was carried on simultaneously in all +four, so that the division into contracts had no bearing on the methods +of work adopted, and these will now be described as a whole and with no +further reference to the different sections. + + +Excavation. + +Work was started on the New York side on April 18th, 1904, the Weehawken +shaft being at that date still under construction. As will have been +noted in the description of the shafts, the contractor found a shaft +already prepared for his use, and cross-drifts at grade and at right +angles to the future tunnels, and extending across their entire width. +The first essential was to get access to the shield chambers, which were +to lie about 330 ft. to the west of the shaft, so that the construction +of these enlargements in which the shields for the subaqueous tunnels +were to be built might be finished as soon as possible and thus allow +the earliest possible start to be made with the shield-driven tunnels. + +With this in view, two bottom headings, on the center line of each of +the two tracks, were driven westward from the western cross-heading at +the foot of the shaft. When about 138 ft. had been made in this way, +the two headings were brought together and a break-up was made to the +crown level of the tunnel, as the depth of rock cover was doubtful. From +this break-up a top heading was driven westward to Station 200 + 30. +While widening the heading out at Station 200 + 20 the rock was +penetrated on the south side. The exposed wet sand and gravel started to +run, and, as a consequence, a change in design was made, the shield +chambers (and consequently the start of the shield-driven tunnels) being +moved eastward from their original location 133 ft. to their present +location. A certain amount of time was necessarily spent in making these +changes of design, which involved a rearrangement of the whole layout +from the Terminal Station to the start of the River Tunnels. On July +5th, 1904, however, the new design was formally approved. No sooner had +this been decided than a strike arose on the work, and this was not +settled until August 1st, 1904, but from that time the work progressed +without delay. No further reference will be made to the work in the +shield chambers, as that will come under the heading of "River Tunnels," +being of the segmental, cast-iron lined type. + +A top heading was now driven over the original bottom heading west of +the shaft, and at the same time the original cross-drifts from the shaft +were amalgamated with and broken down by a heading driven at the crown +level of the "Intercepting Arch" which here cuts across the ordinary run +of tunnel at right angles and affords access to the tunnels from the +shafts. + +The excavation of the upper portion of the intercepting arch at its +southern end gave some trouble, and caused some anxiety, as the rock +cover was penetrated and the wet sand and gravel were exposed. This made +it necessary to timber all this section heavily, and the tracks of the +New York Central Railroad directly above were successfully supported. +The general way in which this timbering was carried out will be +described under the head of "Timbering." + +Meanwhile, the excavation of the tunnels west of the intercepting arch +was continued until the North and South Tunnels were taken out to their +full outlines, leaving a core of rock between them. This core was +gradually removed, and timbering supporting the rock above the middle +wall was put in as excavation went on. The ground, which was entirely of +micaceous schist, typical of this part of Manhattan, seamed with veins +of granite, was rather heavy at the west end, or adjacent to the shield +chambers, and required complete segmental timbering across the whole +span. One heavy fall of rock in the corewall between the North and South +Tunnels took place on November 2d, but fortunately did not extend beyond +the limits of the permanent work. On November 7th, 1904, the excavation +east of the intercepting arch was begun by driving a bottom heading in +the South Tunnel. This was continued to Station 197 + 14 and then was +taken up to the crown level and worked as a top heading with the view of +keeping track, by making exploratory borings upward from the roof at +frequent intervals, of the rock surface, which was here irregular and +not known with any degree of certainty. The work was not pressed with +any vigor, because all efforts were then being bent toward excavating +from the River Tunnels as much rock as possible. In Section Gy-East the +conditions were exceptionally variable, as the rock was subject to +sudden changes from a soft crumbling mica schist to broad bands of hard +granite, and, in addition, the rock surface was very irregular, and, for +a good length of this section, was below the crown of the tunnel, a +condition which led to the adoption of the cut-and-cover method for part +of the work. + +The irregularity in conditions called for varying methods of procedure, +but in general the methods were as shown on Plate XXXIII, and described +as follows: + +_In Solid Rock._--Where there was plenty of good rock cover, a top +middle heading was driven, which was afterward widened out to the full +cross-section of the twin tunnel arches. If necessary, a few lengths of +segmental timbering were put in before taking down the bench, which was +generally kept some 40 or 50 ft. behind the breast of the heading. After +the bench was down, the middle conduit trench was excavated and the +trimming done. + +_In Soft Rock._--Where there was not enough rock cover, or where there +was actual soft ground in the roof, wall-plate headings at the springing +line level were driven ahead of the remainder of the work. The +wall-plates were laid in these, the roof was taken out in short lengths, +and segmental timbering spanning from wall-plate to wall-plate was put +in. The roof being thus held, the bench excavation proceeded without +trouble. Where the rock was penetrated and soft ground showed in the +roof, poling boards were driven ahead over the crown-bars, as shown in +Fig. 4. + +_Cut-and-Cover Work._--After some 225 ft. had been driven from the +intercepting arch, it was found that the crown of the tunnel was +continually in soft ground. To ascertain the extent of this condition +the contractor decided to make soundings as far as Tenth Avenue, which +was done by sinking trial pits and making wash-borings in the street. +These soundings showed that there would be soft ground in the crown from +Station 194 + 75 to Station 194 + 25 (at one point to a depth of 12 ft. +below the crown), and on each side of this section the cover was +insufficient from Station 193 + 58 to Station 195 + 30. This condition +being known, it was decided to adopt cut-and-cover work for this length, +the principal reasons being that repairs to sewers, streets, and drains +would be no more, and probably less, expensive than with the tunnel +method; the underpinning of a heavy brick brewery building adjoining the +works on the north side would be facilitated, and the opening in the +street, through which muck and materials could be handled, would relieve +the congested shaft, through which the large volume of muck from the +River Tunnels was then being conveyed. On the other hand, the +cut-and-cover method was adversely affected by the presence of a heavy +timber trestle built down the south side of the street and over which +passed all the excavation from the Terminal Station, amounting to a very +heavy traffic. As this trestle had to be supported, it complicated the +situation considerably. Very little active progress was made between +June, 1905, and April, 1906, as the contractor's energies during that +time were much taken up with the progress of the shield-driven tunnels. +In April, 1906, preparations were made to start a 50-ft. length of open +cut, rangers being fixed and sheathing driven; and the sewer which ran +down the middle of this street was diverted to the outside of the +open-cut length. + +April and May were occupied in driving the sheathing down to rock, +supporting the trestle, underpinning the adjoining brewery, and +excavating the soft material above the rock. On June 2d, 1906, rock was +reached, and, by July 31st, the excavation was down to subgrade over +nearly the whole 50 ft. in the first length. In the meantime another +length was opened up, and eventually a third. + +The surface of the rock now seemed to be rising, and the heavy buildings +had been passed, so that tunneling was reverted to for the rest of the +work, though many difficulties were caused by soft rock in the roof from +time to time. + +[Illustration: METHOD OF DRIVING ROOF LAGGING IN SOFT GROUND. FIG. 4.] + +When the excavation for the open-cut work of the Terminal Station had +advanced to the line of Tenth Avenue, the contractor started a heading +from this point and drove westward under Tenth Avenue until the headings +driven eastward from the cut-and-cover portion, were met. + +This was done to expedite the work under Tenth Avenue, where the ground +was not very good, where there were several important gas and water +mains in the street, and where, moreover, the tunnels were of +exceptionally large span (24 ft. 6 in.), making a total width of some 60 +ft. for the excavation. The excavation for the New York Tunnels was +practically finished in January, 1908. + +_Drilling and Blasting._--The foregoing short description will serve to +show in a general way the scheme adopted in making the excavation. A few +details on drilling and blasting methods may not be out of place. + +Percussive drills run by air pressure were used. They were +Ingersoll-Sergeant, Nos. 3½, A-86, C-24, and F-24. The air came from +the high-pressure compressor previously described. This compressor, +without assistance, could supply air for nine drills, but, when fed by +compressed air from the lower pressure, its capacity was increased three +or four times. + +The air was compressed to 100 lb. per sq. in. in the power-house, and +was delivered at about 80 lb. per sq. in. at the drills. A 3-in. air +line was used. The drill steel was 1-1/8-to 1-3/8-in. octagonal. The +holes were about 3¼ in. in diameter at starting and 2-5/8 in. at the +full depth of 10 ft. The powder used on the New York side was 40% +Forcite, the near presence of heavy buildings and lack of much rock +cover necessitating light charges and many holes spaced close together. + +To compensate the contractor for the inevitable excavation done outside +the neat lines of the masonry lining, the excavation was paid for to the +"Standard Section Line" which was 12 in. outside the neat lines on top +and sides and 6 in. outside at the bottom of the cross-section. The +actual amount of excavation done was about 11% greater than that paid +for. The distance excavated beyond the neat line, because of the very +heavy timbering necessary, was about 2.1 ft. instead of the 1 ft. +allowed, and at the bottom about 0.85 ft. instead of the 0.50 ft. paid +for. + +For a period of 5 months detailed records were kept of the drilling and +blasting. About 12,900 cu. yd. of excavation are included. A sketch and +table showing the method of driving the heading, the number and location +of the holes drilled, and the amount of powder used, is given in Fig. 5. +From this and similar figures the information in Table 5 is derived. + +TABLE 5. + + +========================+=======+=======+=======+======+=======+======| + | | FEET OF HOLE | POUNDS OF POWDER | + | |DRILLED PER CUBIC YARD | USED PER CUBIC YARD | + | | OF EXCAVATION. | OF EXCAVATION. | + | +-------+-------+-------+------+-------+------| + |Portion of excavation. |15-ft. |19-ft. |24-ft. | | | | + | | 4-in. | 6-in. | 6-in. |15-ft.|19-ft. |24-ft.| + | |span-- |span-- |span-- |4-in. | 6-in. | 6-in.| + | | twin | twin | twin | | | | + | |tunnel.|tunnel.|tunnel.| | | | + |------------------------+-------+-------+-------+------+-------+------+ + |Wall-plate heading[C] | 13.0 | 10.97 | 10.97 |3.77 | 2.85 | 2.85 | + | | | | | | | | + |Total heading[C] | 7.87 | 8.17 | 7.81 |2.31 | 2.02 | 1.78 | + | | | | | | | | + |Bench and raker bench[C]| 5.97 | 6.15 | 7.56 |0.94 | 0.93 | 1.13 | + | | | | | | | | + |Trench[C] | 9.82 | 15.96 | 18.10 |1.84 | 2.49 | 2.73 | + |------------------------+-------+-------+-------+------+-------+------+ + |Average for section[C] | 6.69 | 7.43 | 8.95 |1.28 | 1.30 | 1.45 | + |------------------------+-------+-------+-------+------+-------+------| + |Actual amount[D] | 6.82 | 7.27 | 8.95 |1.22 | 1.24 | 1.27 | + +========================+=======+=======+=======+======+=======+======+ + +[C] Figures taken from typical cross-sections. + +[D] This gives the actual amount of drilling done and powder used per +cubic yard for the whole period of 5 months of observation, but as this +length included 280 ft. of heading and only 220 ft. of bench, the +average figures (for powder especially) are too low. + +Table 6 gives the rate and cost of drilling, and the cost of powder. It +will be seen that the average rate of drilling was 2.71 ft. per hour per +drill or 27.1 ft. per drill per shift. + +Table 7 shows the result of observation as to the time taken in various +subdivisions of the drilling operations. These observations were not +carried on for a long enough period to give correct results, but the +percentages of time spent on each division of the operation are believed +to be about right. The headings of this table are self-explanatory. The +necessary delays include all time spent in changing bits, making +air-line connections, etc. The unnecessary delays are stoppages caused +by lack of supplies or insufficient air pressure. + +By Table 6 it will be noticed that the cost of labor for drilling and +sharpening steels was about $0.29 per lin. ft. of hole drilled. The +total cost, including repairs, supply of air, etc., came to about $0.38, +as will be seen from Table 8. + +_Timbering._--On the New York side nearly the whole length of the +excavation needed timbering, to a greater or less extent, and for the +most part required timbering of quite a heavy type. + +TABLE 6.--ROCK TUNNEL EXCAVATION UNDER 32D STREET, EAST OF CUT-AND-COVER +SECTION. DRILLING AND BLASTING.--DETAILED COST OF LABOR IN DRILLING, +ALSO QUANTITY AND COST OF POWDER USED. + + +=====================================================================+ + | DRILLING AND BLASTING. | + |-----+-----+------+------+------+-----+-----+------+-----+-----+-----| + |Type.|Date.|Total feet drilled. | No. drill shifts| Feet drilled | + | | | | | | of (10-hour.) |per man per hour.| + | +-----+------+------+------+-----+-----+------+-----+-----+-----+ + | |1907 |Head- |Bench |Total |Head-|Bench|Total |Head-|Bench|Total| + | | | ing | | | ing | | | ing | | | + |-----+-----+------+------+------+-----+-----+------+-----+-----+-----+ + |_Ke._|May | 2,971| 5,578| 8,549| 98 | 204 | 302 |3.031|2.734|2.831| + | |June | 2,093| 6,194| 8,287| 85 | 223 | 308 |2.462|2.777|2.691| + | |July | | 7,627| 7,627| | 268 | 268 | |2.845|2.845| + | |Aug. | | 2,552| 2,552| | 95 | 95 | |2.688|2.688| + | |Sept.| | 2,133| 2,133| | 79 | 79 | |2.700|2.700| + | +-----+------+------+------+-----+-----+------+-----+-----+-----+ + | |Total| 5,064|24,084|29,148| 183 | 869 |1,052 |2.767|2.77 |2.77 | + |-----+-----+------+------+------+-----+-----+------+-----+-----+-----+ + |_Ki._|May | 6,976| | 6,976| 216 | | 216 |3.229| |3.229| + | |June | 4,089| | 4,089| 135 | | 135 |3.029| |3.029| + | |July | | 3,733| 3,733| | 140 | 140 | |2.666|2.666| + | |Aug. | | 6,715| 6,715| | 249 | 249 | |2.769|2.769| + | |Estim| |14,742|14,742| | 46 | 546 | |2.700|2.700| + | +-----+------+------+------+-----+-----+------+-----+-----+-----+ + | |Total|11,065|25,190|36,255| 351 | 935|1,286 |3.152|2.694|2.819| + |-----+-----+------+------+------+-----+-----+------+-----+-----+-----+ + |_Ko._|May | | 1,617| 1,617| | 55| 55 | |2.921|2.921| + | |June | | 2,948| 2,948| | 107| 107 | |2.755|2.755| + | |July | | 3,734| 3,734| | 131| 131 | |2.850|2.850| + | |Aug. | | 8,260| 8,260| | 290| 290 | |2.848|2.848| + | |Estim| | 4,787| 4,787| | 285| 285 | |1.180|1.680| + | +-----+------+------+------+-----+-----+------+-----+-----+-----+ + | |Total| |21,346|21,346| | 868| 868 | |2.460|2.460| + |-----+-----+------+------+------+-----+-----+------+-----+-----+-----+ + |Grand|Total|16,129|70,620|86,749| 534 |2,672|3,206 |3.020|2.710|2.710| + +=====+=====+======+======+======+=====+=====+======+=====+=====+=====+ + + +==================================================+=====================+ + | DRILLING AND BLASTING | POWDER USED. | + |-----+----------+------+--------------------------+--------+-------+----+ + | | | | Cost of labor only. | | | | + | | | | Drilling and sharpening. | | | | + | | | +------+------+-------+----+ | | | + | | | | | | Per | | | Cost | | + | | | | | | cubic | | | per | | + | | | | | | yard. | | | cubic | | + | | | | | | | | |yard at| | + | | | | | | | | | 11 | | + | | | | | | | | | cents | | + | | | | | | | | | per | | + | | | | | | | | |pound. | | + | +----------+------+------+------+-------+----+--------+-------+----+ + |Type.| Quantity | |Total.| Per |Actual.|Paid| Total |Actual.|Paid| + | | of | | |linear| |for |Quantity| |for.| + | |excavation| | |feet. | | | | | | + | | in cubic | | | | | | | | | + | | yards. | | | | | | | | | + | +----------+------+------+------+-------+----+--------+-------+----+ + | | Actual. | Paid | $ | $ | $ | |Pounds. | $ | $ | + | | [E] | for | | | | | | | | + | | | [F] | | | | | | | | + |-----+----------+------+------+------+-------+----+--------+-------+----+ + |_Ke._| 1,736 | 1,664| 2,331| 0.27 | 1.34 |1.40| 1,595 | 0.10 |0.10| + | | 809 | 698| 2,440| 0.29 | 3.01 |3.49| 1,960 | 0.27 |0.31| + | | 1,022 | 960| 2,031| 0.26 | 1.98 |2.11| 966 | 0.10 |0.11| + | | 743 | 716| 640| 0.25 | 0.86 |0.89| 430 | 0.06 |0.07| + | | 238 | 238| 533| 0.25 | 2.24 |2.24| 280 | 0.13 |0.13| + | |----------+------+------+------+-------+----+--------+-------+----+ + | | 4,548 | 4,276| 7,975| 0.27 | 1.75 |1.87| 5,231 | 0.13 |0.13| + |-----+----------+------+------+------+-------+----+--------+-------+----+ + |_Ki._| 614 | 527| 1,604| 0.23 | 2.61 |3.04| 1,230 | 0.22 |0.26| + | | 357 | 259| 1,234| 0.30 | 3.45 |4.76| 1,036 | 0.32 |0.44| + | | 530 | 404| 1,084| 0.29 | 2.04 |2.68| 550 | 0.11 |0.15| + | | 925 | 890| 1,901| 0.28 | 2.05 |2.13| 905 | 0.10 |0.11| + | | 3,254 | 2,908| 4,570| 0.31 | 1.40 |1.57| 2,470 | 0.08 |0.09| + | |----------+------+------+------+-------+----+--------+-------+----+ + | | 5,680 | 4,988|10,393| 0.29 | 1.83 |2.08| 6,191 | 0.12 |0.14| + |-----+----------+------+------+------+-------+----+--------+-------+----+ + |_Ko._| 250 | 188| 471| 0.29 | 1.88 |2.50| 376 | 0.17 |0.22| + | | 496 | 347| 883| 0.29 | 1.78 |2.54| 357 | 0.08 |0.11| + | | 626 | 606| 1,003| 0.27 | 1.60 |1.65| 609 | 0.11 |0.11| + | | 718 | 709| 2,161| 0.26 | 3.00 |3.04| 918 | 0.14 |0.14| + | | 605 | 535| 2,397| 0.50 | 3.96 |4.48| 762 | 0.14 |0.16| + | |----------+------+------+------+-------+----+--------+-------+----+ + | | 2,695 | 2,385| 6,915| 0.32 | 2.57 |2.90| 3,022 | 0.12 |0.14| + | |---------+-------+------+------+-------+----+--------+-------+----+ + | |12,923 |11,649|25,283| 0.29 | 1.96 |2.17|14,444 | 0.12 |0.14| + +=====+==========+======+======+======+=======+====+========+=======+====+ + +The work done during the 5 months when these analyzed cost figures were +kept includes 280 ft. of bench and 220 ft. of heading. This excess of +bench over heading causes the general average amounts per cubic yard to +be too low. + +[E] Actual amount of excavation. + +[F] Amount of excavation paid for. + +[Illustration: 24' 6" SPAN TWIN TUNNELS DETAILS OF METHOD OF DRILLING +AND BLASTING IN A TYPICAL (NOT EXACT AVERAGE) SECTION] + + +---------+--------+--------+-----+-----+------+------+-------+ + | Drilling and Firing Data for | + | Each Sub-division of Section | + |---------+--------+--------+-----+-----+------+------+-------| + | Sub | Volume | No. of | No. | No. |Total |Linear| Total | + |divisions|of each |sets of | of | of | lbs. | feet |length | + | | sub- | holes |holes|times| of | of |drilled| + | |division| | in |fired|powder|tunnel| | + | |paid for| | set | | per |broken| | + | | | | | | hole | | | + | | | | | |fired | | | + |---------+--------+--------+-----+-----+------+------+-------| + | _a_ | _b_ | _c_ | _d_ | _e_ | _f_ | _g_ | _h_ | + |---------+--------+--------+-----+-----+------+------+-------| + | _A_ | 17.775 | {[G] 1 | 6 | 3 | 4.50 | | | + | | | {[H] 1 | 9 | 1 | 1.50 | | | + | | | {[I] 1 | 6 | 1 | 1.00 | | | + | | | {[J] 1 | 6 | 1 | 0.75 | 6.0 | 195 | + | | | | | | | | | + |---------+--------+--------+-----+-----+------+------+-------| + | _A'_ | 1.00 | 2 | 3-4 | 1 | 0.25 | 5.0 | 21 | + |---------+--------+--------+-----+-----+------+------+-------| + | _B_ | 5.925 | {[G] 2 | 3-4 | 1 | 1.00 | 4.0 | 35 | + |---------+--------+--------+-----+-----+------+------+-------| + | _C_ | | {[K] 1 | 3 | 2 | 1.125| | | + | | 33.33 | 4 | 7 | 1 | 1.125| 5.0 | 186 | + |---------+--------+--------+-----+-----+------+------+-------| + | _D_ | 6.665 | 2 | 5-6 | 1 | 0.75 | 3.0 | 33 | + |---------+--------+--------+-----+-----+------+------+-------| + | | | | + | | | | + |=========+========+========+=====+=====+======+======+=======| + | _E_ | 50.00 | | 5 | 1 | 1.50 | 5.0 | 405 | + |---------+--------+--------+-----+-----+------+------+-------| + | _F_ | 88.88 |{ 10.5| 4 | 2 | 1.50 | | | + | | |{[L] 5.0| 4 | 1 | 1.50 | 4.0 | 682 | + |---------+--------+--------+-----+-----+------+------+-------| + | _G_ | 22.22 | 5.5| 4 | 2 | 1.00 | 5.0 | 132 | + |---------+--------+--------+-----+-----+------+------+-------| + | | | | + | | | | + |=========+========+========+=====+=====+======+======+=======| + | _H_ | 9.77 |{ 5 | 3 | 1 | 0.50 | | | + | | |{ 4 | 6 | 1 | 0.50 | 6.0 | 156 | + |---------+--------+--------+-----+-----+------+------+-------| + | _I_ | 26.66 | 8 | 5 | 1 | 1.00 | 6.0 | 252 | + |---------+--------+--------+-----+-----+------+------+-------| + | | | | + | | | | + | | |========+=====+=====+======+======+=======| + | | | | + | | | | + | | | | + | | |========+=====+=====+======+======+=======| + | | | | + +---------+--------+--------+-----+-----+------+------+-------+ + + +---------+------+-------+------+------+---------+-------+------+ + | Drilling and Firing Data for | + | Total Sections | + |---------+------+-------+------+------+---------+-------+------| + | Sub |Total |Length | Cu. | Cu. | Total | Total | Total| + |divisions|length|drilled| yds. | yds. | lbs. of |lbs. of| lbs. | + | | of | per | per | per | powder | powder| of | + | |simi- |linear |linear|linear| per | per |powder| + | |lar |foot of| foot | foot | linear | foot | per | + | |head- |tunnel | of | of | foot of |drilled|cubic | + | |ings | |tunnel|tunnel| tunnel | | yard | + |---------+------+-------+------+------+---------+-------+------| + | _a_ | _i_ | _j_ | _k_ | _l_ | _m_ | _n_ | _o_ | + |---------+------+-------+------+------+---------+-------+------| + | _A_ | |Sigma | | | | | | + | | | c + d |b + i | j |c + d + f| m | m | + | | | ----- |------| --- | ----- | --- | --- | + | | | g | g | k | g | j | k | + | | 2 | 65.00 | 5.925|10.97 | 17.00 | 0.261 |2.848 | + |---------+------+-------+------+------+---------+-------+------| + | _A'_ | 2 | 8.40 | 0.400|21.00 | 0.70 | 0.166 |1.750 | + |---------+------+-------+------+------+---------+-------+------| + | _B_ | 2 | 17.50 | 2.962| 5.90 | 3.50 | 0.200 |1.181 | + |---------+------+-------+------+------+---------+-------+------| + | _C_ | | | | | | | | + | | 1 | 37.20 | 6.666| 5.58 | 6.975 | 0.187 |1.046 | + |---------+------+-------+------+------+---------+-------+------| + | _D_ | 2 | 22.00 | 4.444| 4.95 | 5.500 | 0.250 |1.237 | + |---------+------+-------+------+------+---------+-------+------| + |Total for| |150.10 |20.397| 7.81 | 33.675 | 0.227 |1.778 | + | Heading | | | | | | | | + |=========+======+=======+======+======+=========+=======+======| + | _E_ | 1 | 81.00 |10.000| 8.10 | 13.500 | 0.167 |1.350 | + |---------+------+-------+------+------+---------+-------+------| + | _F_ | | | | | | | | + | | 1 |170.50 |22.222| 7.67 | 23.230 | 0.136 |1.046 | + |---------+------+-------+------+------+---------+-------+------| + | _G_ | 1 | 26.40 | 4.444| 5.94 | 4.400 | 0.166 |0.990 | + |---------+------+-------+------+------+---------+-------+------| + |Total for| |277.90 |36.666| 7.56 | 41.150 | 0.150 |1.133 | + | Bench | | | | | | | | + |=========+======+=======+======+======+=========+=======+======| + | _H_ | | | | | | | | + | | 1 | 26.00 | 1.628|15.96 | 3.250 | 0.125 |1.995 | + |---------+------+-------+------+------+---------+-------+------| + | _I_ | 2 | 84.00 | 4.444|18.90 | 13.333 | 0.158 |3.000 | + |---------+------+-------+------+------+---------+-------+------| + |Total of | |110.00 | 6.072|18.10 | 16.583 | 0.151 |2.731 | + | Trench | | | | | | | | + |=========+======+=======+======+======+=========+=======+======| + |Total for| |548.00 |63.135| 8.95 | 91.408 | 0.172 |1.446 | + | Whole | | | | | | | | + |Section | | | | | | | | + |=========+======+=======+======+======+=========+=======+======| + |Powder taken at 0.5 lb. per stick | + +---------+------+-------+------+------+---------+-------+------+ + +[G] 6 Cut Holes-8 feet (Black circle) + +[H] 9 First Side Rd. and Bottom-7 feet (Circle with dot in it) + +[I] 6 Back Round-7 feet (Circle with line in it) + +[J] 6 Top Back Round-7 feet (Circle with x in it) + +[K] A' 7 Holes-3 feet (Open circle) + +[L] line holes (Plus sign) + +TABLE 7.--Analysis of Drilling Time on Section Gy-East. + + +========+======+========+=====+=====+=======+========+========+=======+ + | | | | AVERAGE TIME TAKEN: | + |Position|Nature| No. of |-----+-----+-------+--------+--------+-------| + | in | of | Drill | | | | | | | + |Section.|Rock. | Shifts |Set- |Dril-|Neces- |Unneces-| Taking |Loading| + | | |observed|ting |ling.| sary | sary | down | and | + | | | for | up. | |delays.|delays. |machine.|firing.| + | | |average.| | | | | | | + |--------+------+--------+-----+-----+-------+--------+--------+-------| + | | | |h. m.|h. m.| h. m. | h. m. | h. m. | h. m. | + | | | |-----+-----+-------+--------+--------+-------| + |Heading |Quartz| 8 |0:38 |4:52 | 1:40 | | 0:05 | 0:04 | + | | | | | | | | | | + |Heading | Hard | 1 |0:15 |8:00 | 1:45 | | | | + | | mica | | | | | | | | + | |schist| | | | | | | | + | | | | | | | | | | + | Bench |Quartz| 23 |1:23 |5:57 | 2:23 | 0:05 | 0:05 | 0:07 | + | | | | | | | | | | + | Bench |Medium| 16 |1:10 |6:08 | 1:50 | 0:12 | 0:07 | 0:07 | + | | mica | | | | | | | | + | |schist| | | | | | | | + | | | | | | | | | | + | Center |Medium| 10 |0:58 |5:53 | 1:33 | 0:06 | 0:12 | 0:30 | + | trench | mica | | | | | | | | + | |schist| | | | | | | | + | | | | | | | | | | + | Center | Soft | 9 |1:10 |6:40 | 1:17 | 0:10 | 0:20 | 0:23 | + | trench | mica | | | | | | | | + | |schist| | | | | | | | + |--------+------+--------+-----+-----+-------+--------+--------+-------| + |General | | 67 |1:08 |5:58 | 1:53 | 0:07 | 0:09 | 0:12 | + |average | | | | | | | | | + |--------+------+--------+-----+-----+-------+--------+--------+-------| + | Per- | | |11.3%|59.7%| 18.9% | 1.1% | 1.5% | 2% | + |centage | | | | | | | | | + +========+======+========+=====+=====+=======+========+========+=======+ + + +========+======+=========+========+======+======+========+ + | | | AVERAGE TIME TAKEN: | FEET DRILLED. | + |Position|Nature|---------+--------+------+------+--------| + | in | of | | | | | | + |Section.|Rock. | Total |Mucking.|Total.| Per | Per | + | | |drilling.| | |shift.|working | + | | | | | | | hour. | + | | | | | | | | + |--------+------+---------+--------+------+------+--------| + | | | h. m. | h. m. |h. m. | | | + | | |---------+--------+------+------+--------| + |Heading |Quartz| 7:19 | 2:41 |10:00 | 22.0 | 2.86 | + | | | | | | | | + |Heading | Hard | 10:00 | |10:00 | 42.0 | 4.20 | + | | mica | | | | | | + | |schist| | | | | | + | | | | | | | | + | Bench |Quartz| 10:00 | |10:00 | 25.9 | 2.59 | + | | | | | | | | + | Bench |Medium| 9:34 | 0:26 |10:00 | 22.22| 2.32 | + | | mica | | | | | | + | |schist| | | | | | + | | | | | | | | + | Center |Medium| 9:12 | 0:48 |10:00 | 22.0 | 2.39 | + | trench | mica | | | | | | + | |schist| | | | | | + | | | | | | | | + | Center | Soft | 10:00 | |10:00 | 26.44| 2.64 | + | trench | mica | | | | | | + | |schist| | | | | | + |--------+------+---------+--------+------+------+--------| + |General | | 9:27 | 0:33 |10:00 | 24.1 | 2.54 | + |average | | | | | | | + |--------+------+---------+--------+------+------+--------| + | Per- | | 94.5% | 5.5% | 100% | | | + |centage | | | | | | | + +========+======+=========+========+======+======+========+ + +TABLE 8.--ANALYZED COST OF DRILLING. + + +=============+===========================+===========================+ + | | COST PER FOOT OF HOLE | COST PER DRILL SHIFT | + |Item of Cost.| DRILLED. | | + | +-------+-----+-----+-------+-----+------+------+-------+ + | | 15 ft | 9 ft|24 ft|Average|15 ft|19 ft |24 ft |Average| + | | 4 in | 6 in| 6 in| | 4 in| 6 in | 6 in | | + |-------------+-------+-----+-----+-------+-----+------+------+-------+ + |Drilling | $0.25 |$0.28|$0.31| $0.28 |$6.95| $7.75| $7.60| $7.45 | + |labor | | | | | | | | | + | | | | | | | | | | + |Sharpening | 0.02 | 0.02| 0.01| 0.016| 0.58| 0.42| 0.34| 0.43 | + | | | | | | | | | | + |Drill steel | 0.007|0.007|0.006| 0.007| 0.19| 0.20| 0.15| 0.19 | + |(5 in. per | | | | | | | | | + |drill shift) | | | | | | | | | + | | | | | | | | | | + |Drill repairs| 0.02 | 0.02| 0.02| 0.02 | 0.61| 0.59| 0.42| 0.54 | + | | | | | | | | | | + |High-pressure|[M]0.05| 0.04| 0.07| 0.07 | 1.39| 1.86| 1.67| 1.82 | + |air | | | | | | | | | + |-------------+-------+-----+-----+-------+-----+------+------+-------+ + |Totals | $0.35 |$0.38|$0.41| $0.385|$9.67|$10.82|$10.18|$10.43 | + +=============+=======+=====+=====+=======+=====+======+======+=======+ + +[M] This is an estimated figure, ascertained by taking a proportion of +the whole charge for plant running. + +_General Methods._--Whenever any considerable support was needed for the +ground, segmental timbering was used. In most cases, this was supported +by wall-plates at the springing line, and was set with an allowance for +settlement, so that it would be clear of the work when the masonry +lining was put in. As the twin-tunnel section involved the excavation of +the North and South Tunnels at the same time, the cross-section of the +upper part of the excavation consisted of two quadrants rising from the +springing line and connected at the top by a horizontal piece from 19 to +28 ft. in length. This made a rather flat arch to support by timbering. + +The timber for the segmental work was 12 by 12-in. yellow pine. In light +ground the bents were spaced at 5-ft. centers, in heavy ground 2-ft. +6-in. centers. + +When the soft ground in the roof was struck, posts had to be used in the +heading to support the caps. When the bench was removed, the posts were +replaced by others down to the bottom of the excavation. These long +posts were a great hindrance to all the work, and each replacement of +short posts by long ones meant a settlement of the caps; consequently, +it was decided to use in the section east of the cut-and-cover, where +all the ground was heavy, a temporary inner bent of segmental timber, +within and reinforcing the permanent bent, and resting on separate +wall-plates. This is shown by Fig. 6. These temporary bents were inside +the work, and were removed as the arch was built. However, the caps +settled considerably in some cases, so that it was not possible to do +away with posting entirely. + +In heavy ground the caps were set about 1 ft. above the neat line of the +crown of the brick arch, in some cases they were set only 6 in. above, +but the settlement was often more than this, causing great trouble in +cutting out the encroaching timber when the arch had to be built. + +[Illustration: DETAILS OF LONGITUDINAL SECTIONAL SHOWING METHOD OF +PLACING LAGGING IN CROWN WITH SOFT ROOF TYPICAL SECTION LOOKING EAST +FIG. 6.] + + +In the tunnels east of the cut-and-cover portion, wall-plate headings +were driven (shown by areas marked _A_ on Fig. 5), and, when a length of +wall-plate had been set, the full-width heading was advanced a foot or +two at a time, the timber segmental bents being set up as soon as +possible; lagging was then driven over the cap into the soft ground. +Fig. 6 shows the double set of segmental bents adopted in the 15-ft. +4-in. twin tunnels east of the cut-and-cover section. + +When the soft ground came down so low as to interfere with the +excavation of the wall-plate headings, a small heading was driven into +the soft ground on the line of the ends of the caps, and lagging was +driven down from this to the wall-plate heading, as illustrated in Fig. +4. + +In the 19-ft. 6-in. tunnels the wall-plate for the inner bent was +supported by a side-bench, termed the "Raker" bench. This was left in +position until the rest of the bench and the middle subgrade conduit +trench had been excavated; it was then possible to support the caps by +two rows of posts from subgrade level, take out the inner bents, and +excavate the raker bench. + +The 24-ft. 6-in. twin tunnels, which are at the extreme eastern end of +this section, adjoining the open-cut work of the Terminal Station, and +under Tenth Avenue, were driven from the Terminal Station-West, and the +timbering had to be made very secure on account of the pipes and sewers +in the street above. Detailed records were kept of the amount of timber +used and the cost of labor and material expended in timbering. These +records cover the same portion of tunnel as that for which the detailed +records of drilling costs, previously referred to, were kept. These +records are shown in Tables 9 and 10. It will be noted that the timber +used in blocking, that is, filling up voids outside the main timbering, +amounted to more than two-thirds of the total timber, and that the cost +of labor in erecting the timbering exceeds the prime cost of the timber +by about one-third. The following distinction is made between permanent +and temporary timbering: The permanent timbering is that which is +concreted in when the masonry is built; the temporary consists of the +lower bents and posts, which have to be removed when the masonry is +built. + +_Force Employed in Excavation._--A typical day's working force for +drilling, blasting, mucking, and timbering is shown in Table 11. + +Where there was any large quantity of soft ground in the roof, the +timber gang was much larger than shown in Table 11, and was helped by +the mucking gang. The drillers did most of the mucking out of the +heading before setting up the drills. + +_Excavation of Weehawken Rock Tunnels._--This subject may be dismissed +in a few words, as very few features of interest were called into play. +The rock was of good quality, being the sandstone typical of this part +of the country. Little or no timbering was needed, there were no +buildings above the tunnel to be taken care of, and large charges of +powder could be used. + +TABLE 9.--SUPPLEMENTARY ANALYSIS OF TIMBERING, ROCK TUNNEL EXCAVATION +UNDER 32D STREET, EAST OF CUT-AND-COVER SECTION. ANALYZED COST OF +TIMBERING, PER FOOT RUN AND PER BENT. + + +=============================+================================ + | | _Ke_ + | |--------+------------+---------- + | |Per foot|Per bent, |Per cubic + | |run of |3 ft, 6 in.,|yard + | |tunnel |center to |excavation + | | |center | + |-----------------------------+--------+------------+---------- + |PERMANENT TIMBERING. | | | + |Lumber in feet, B. M. | | | + | Upper Bent. | 274 | 685 | 7.8 + | Blocking. | 294 | 735 | 8.3 + | Total. | 568 | 1,420 | 16.1 + |Cost, in dollars. | | | + | Lumber. | 23.75| 59.38 | 0.67 + | Labor. | 37.50| 93.75 | 1.06 + | Total. | 61.25| 153.13 | 1.73 + | | | | + |TEMPORARY TIMBERING. | | | + |Lumber in feet, B. M. | | | + | Lower Bent. | 479 | 11.97 | 13.6 + | Blocking. | 193 | 483 | 5.5 + | Total. | 672 | 16.80 | 19.1 + |Cost, in dollars. | | | + | Lumber. | 29.13| 72.81 | 0.82 + | Erection labor. | 28.85| 72.13 | 0.82 + | Removal labor. | 8.29| 20.73 | 0.23 + | Total labor. | 37.14| 92.86 | 1.05 + | Total. | 66.27| 165.67 | 1.87 + | | | | + |GRAND TOTAL. | | | + |Lumber in feet, B. M. |1,240 | 3,100 | 35.2 + |Cost, in dollars. | | | + | Lumber. | 52.88| 132.19 | 1.49 + | Labor. | 74.64| 186.61 | 3.60 + | Total. | 127.52| 318.80 | + |-----------------------------+--------+------------+---------- + | | _Ki_ + | |--------+------------+---------- + | |Per foot|Per bent, |Per cubic + | |run of |3 ft, 6 in.,|yard + | |tunnel |center to |excavation + | | |center | + |-----------------------------+--------+------------+---------- + |PERMANENT TIMBERING. | | | + |Lumber in feet, B. M. | | | + | Upper Bent. | 227 | 830 | 5.3 + | Blocking. | 164 | 601 | 3.8 + | Total. | 391 | 1,431 | 9.1 + |Cost, in dollars. | | | + | Lumber. | 16.84| 61.56 | 0.39 + | Labor. | 12.82| 46.88 | 0.30 + | Total. | 29.66| 108.44 | 0.69 + | | | | + |TEMPORARY TIMBERING. | | | + |Lumber in feet, B. M. | | | + | Lower Bent. | 186.33| 681.25 | 4.33 + | Blocking. | 42.80 156.50 | 0.99 + | Total. | 229.13| 837.75 | 5.32 + |Cost, in dollars. | | | + | Lumber. | 9.65| 35.31 | 0.22 + | Erection labor. | 10.38| 37.97 | 0.24 + | Removal labor. | 9.74| 34.09 | 0.23 + | Total labor. | 20.12| 72.06 | 0.47 + | Total. | 29.77| 107.37 | 0.69 + | | | | + |GRAND TOTAL. | | | + |Lumber in feet, B. M. | 6.20| 22.69 | 14.4 + |Cost, in dollars. | | | + | Lumber. | 26.49| 96.87 | 0.61 + | Labor. | 32.94| 118.94 | 0.77 + | Total. | 59.43| 215.81 | 1.38 + |-----------------------------+--------+----------------------- + | | _Ko_ + | |--------+------------+---------- + | |Per foot|Per bent, |Per cubic + | |run of |3 ft, 6 in.,|yard + | |tunnel |center to |excavation + | | |center | + |-----------------------------+--------+------------+---------- + |PERMANENT TIMBERING. | | | + |Lumber in feet, B. M. | | | + | Upper Bent. | 261 | 962 | 4.1 + | Blocking. | 408 | 1,508 | 6.5 + | Total. | 669 | 24.70 | 10.5 + |Cost, in dollars. | | | + | Lumber. | 28.00| 103.38 | 0.44 + | Labor. | 29.79| 110.00 | 0.47 + | Total. | 57.79| 213.38 | 0.91 + | | | | + |TEMPORARY TIMBERING. | | | + |Lumber in feet, B. M. | | | + | Lower Bent. | 350 | 1,291 | 5.5 + | Blocking. | 61 | 227 | 1.0 + | Total. | 411 | 1,518 | 6.5 + |Cost, in dollars. | | | + | Lumber. | 18.45| 68.16 | 0.29 + | Erection labor. | 20.83| 76.92 | 0.33 + | Removal labor. | 12.16| 44.59 | 0.19 + | Total labor. | 32.99| 121.51 | 0.52 + | Total. | 51.44| 189.67 | 0.81 + | | | | + |GRAND TOTAL. | | | + |Lumber in feet, B. M. |1,080 | 3,988 | 17.1 + |Cost, in dollars. | | | + | Lumber. | 46.45| 171.54 | 0.73 + | Labor. | 62.78| 231.50 | 0.99 + | Total. | 109.23| 403.04 | 1.72 + +=============================+========+============+========= + +TABLE 10.--TIMBERING:--DETAILED COST OF TIMBER, LABOR, AND +SUPERINTENDENCE. ROCK TUNNEL EXCAVATION UNDER 32D STREET, EAST OF +CUT-AND-COVER SECTION. + + +====+=======+======================================+====================+ + | | | | EXCAVATION | | + | | | TIMBER USED, IN | IN CUBIC | COST OF | + | | | FEET, B. M. | YARDS | TIMBER | + | | |------------------------+-------------+--------------------+ + | | | Main |Blocking| Total | | Paid | | | | + | |Date |timber.|timber. |timber.|Actual| for. | Main |Block.|Total.| + | |-------+-------+--------+-------+------+------+------+------+------+ + | |1907 | _a_ | _b_ | _c_ | _d_ | _e_ | _f_ | _g_ | _h_ | + | |-------+-------+--------+-------+------+------+------+------+------+ + |_Ke_|May | 18,016| 15,234 | 33,250| 1,736| 1,664| $810| $565|$1,375| + | |June | 14,048| 11,528 | 25,576| 809| 698| 680| 457| 1,087| + | |July | 20,092| 7,339 | 27,431| 1,022| 960| 900| 300| 1,200| + | |August | 6,485| 2,632 | 9,117| 743| 716| 290| 110| 400| + | |Sept. | 1,632| 2,224 | 3,856| 238| 238| 73| 94| 167| + | |Removal| | | | | | | | | + | |-------+-------+--------+-------+------+------+------+------+------+ + | |Total | 60,273| 38,957 | 99,230| 4,548| 4,276|$2,703|$1,526|$4,229| + |----+-------+-------+--------+-------+------+------+------+------+------+ + |_Ki_|May | | 3,537 | 3,537| 614| 527| | $150| $150| + | |June | 300| | 300| 357| 259| $14| | 14| + | |July | 7,776| 5,811 | 13,587| 530| 404| 350| 233| 583| + | |August | 19,712| 5,702 | 25,414| 925| 890| 887| 220| 1,107| + | |Sept. | 20,556| 9,218 | 29,774| 1,585| 1,501| 925| 325| 1,250| + | |Removal| | | | 1,669| 1,407| | | | + | |-------+-------+--------+-------+------+------+------+------+------+ + | |Total | 48,344| 24,268 | 72,612| 5,680| 4,988|$2,176| $928|$3,104| + |----+-------+-------+--------+-------+------+------+------+------+------+ + |_Ko_|May | 4,332| 8,788 | 13,120| 250| 188| $175| $366| $561| + | |June | 7,132| 10,017 | 17,149| 496| 347| 324| 396| 720| + | |July | 3,070| 200 | 3,270| 626| 606| 134| 10| 144| + | |August | 10,704| 2,102 | 12,806| 718| 709| 481| 80| 561| + | |Sept. | 2,400| 245 | 2,645| 396| 324| 108| 8| 116| + | |Removal| | | | 209| 211| | | | + |----|-------+-------+--------+-------+------+------+------+------+------+ + | |Total | 27,638| 21,352 |48,990 | 2,695| 2,385|$1,242| $860|$2,102| + |----|-------+-------+--------+-------+------+------+------+------+------+ + | |Grand |136,255| 84,577 |220,832|12,923|11,649|$6,121|$3,314|$9,435| + | |total | | | | | | | | | + +====+=======+=======+========+=======+======+======+======+======+======+ + + +====+=======+=======+=======+=======+=======+======+=======+=====+=====| + | | | | | COST PER | COST PER | + | | | | | CUBIC YARD | CUBIC YARD | + | | |COST OF| TOTAL | (ACTUAL). | (PAID FOR). | + | | | Labor | Cost. |-------+-------+------+-------+-----+-----+ + | |DATE | | |Timber.|Labor. |Total.|Timber.|Labor|Total| + | |-------+-------+-------+-------+-------+------+-------+-----+-----+ + | | | | | _h_ | _i_ | _j_ | _h_ | _i_ | _j_ | + | | | | | --- | --- | --- | --- | --- | --- | + | |1907 | _i_ | _j_ | _d_ | _d_ | _d_ | _e_ | _e_ | _e_ | + |----+-------+-------+-------+-------+-------+------+-------+-----+-----+ + |_Ke_|May | $1,792| $3,167| $0.79 | $1.03 | $1.82| $0.82 |$1.07|$1.90| + | |June | 1,576| 2,663| 1.34 | 1.95 | 3.29| 1.55 | 2.25| 3.81| + | |July | 1,580| 2,780| 1.16 | 1.55 | 2.72| 1.25 | 1.64| 2.89| + | |August | 300| 700| 0.53 | 0.40 | 0.94| 0.57 | 0.41| 0.98| + | |Sept. | 60| 227| 0.70 | 0.25 | 0.95| 0.70 | 0.25| 0.95| + | |Removal| 663| 663| | | | | | | + | |-------+-------+-------+-------+-------+------+-------+-----+-----+ + | |Total | $5,971|$10,200| $0.91 | $1.51 | $2.22| $1.00 |$1.40|$2.40| + |----+-------+-------+-------+-------+-------+------+-------+-----+-----+ + |_Ki_|May | $100| $250| $0.24 | $0.16 | $0.40| $0.28 |$0.19|$0.47| + | |June | 44| 58| 0.04 | 0.12 | 0.16| 0.05 | 0.17| 0.22| + | |July | 525| 7,108| 1.10 | 0.99 | 2.09| 1.44 | 1.30| 2.74| + | |August | 1,018| 2,125| 1.20 | 1.10 | 2.30| 1.24 | 1.14| 2.38| + | |Sept. | 1,028| 2,278| 0.79 | 0.65 | 1.44| 0.83 | 0.68| 1.51| + | |Removal| 1,139| 1,139| | 0.68 | 0.68| | 0.81| 0.81| + | |-------+-------+-------+-------+-------+------+-------+-----+-----+ + | |Total | $3,854| $6,958| $0.55 | $0.68 | $1.23| $0.63 |$0.77|$1.40| + |----+-------+-------+-------+-------+-------+------+-------+-----+-----+ + |_Ko_|May | $303| $864| $2.24 | $1.21 | $3.45| $3.00 |$1.61|$4.61| + | |June | 562| 1,282| 1.45 | 1.18 | 2.58| 2.07 | 1.61| 3.68| + | |July | 156| 300| 0.23 | 0.25 | 0.48| 0.23 | 0.26| 0.49| + | |August | 727| 1,288| 0.78 | 1.01 | 1.79| 0.80 | 1.02| 1.82| + | |Sept. | 400| 516| 0.29 | 1.01 | 1.30| 0.36 | 1.23| 1.59| + | |Removal| 535| 535| | 2.56 | 2.56| | 2.54| 2.54| + | |-------+-------+-------+-------+-------+------+-------+-----+-----+ + | |Total | $2,683| $4,785| $0.78 | $1.00 | $1.78| $0.88 |$1.12|$2.00| + |----+-------+-------+-------+-------+-------+------+-------+-----+-----+ + | |Grand |$12,508|$21,943| $0.73 | $0.97 | $1.70| $0.81 |$1.07|$1.88| + | |total | | | | | | | | | + +====+=======+=======+=======+=======+=======+======+=======+=====+=====+ + + +====+===========+======================+ + | | | COST, PER 1,000 | + | | | FT., B. M., OF | + | | | TOTAL TIMBER. | + | | |-------+------+-------| + | | | Total | | | + | | Date |timber.|Labor.|Total. | + | |-----------+-------+------+-------| + | | | _h_ | _i_ | _j_ | + | | | --- | --- | --- | + | | 1907 | _c_ | _c_ | _c_ | + |----+-----------+-------+------+-------| + |_Ke_|May |$41.35 |$53.89| $95.24| + | |June | 42.50 | 61.62| 104.12| + | |July | 43.74 | 57.60| 101.34| + | |August | 43.87 | 32.90| 76.77| + | |Sept. | 43.31 | 15.56| 58.87| + | |Removal | | | | + | |-----------+-------+------+-------| + | |Total |$42.62 |$60.19|$102.81| + |----+-----------+-------+------+-------| + |_Ki_|May |$42.41 |$28.27| $70.68| + | |June | 46.66 |146.33| 193.33| + | |July | 42.91 | 38.64| 81.54| + | |August | 43.56 | 40.06| 83.61| + | |Sept. | 41.98 | 34.53| 76.51| + | |Removal | | | | + | |-----------+-------+------+-------| + | |Total |$42.75 |$53.09| $95.84| + |----+-----------+-------+------+-------| + |_Ko_|May |$42.76 |$23.10| $65.86| + | |June | 41.98 | 32.77| 74.75| + | |July | 44.04 | 47.70| 91.74| + | |August | 43.80 | 56.77| 100.57| + | |Sept. | 43.85 |151.23| 195.08| + | |Removal | | | | + | |-----------+-------+------+-------| + | |Total |$42.91 |$54.75| $97.65| + |----+-----------+-------+------+-------| + | |Grand total|$42.73 |$56.65| $99.38| + +====+===========+=======+======+=======+ + +Work was begun on September 1st, 1904, immediately on the completion of +the work on the shaft. The North and South Tunnels in this case are +completely independent, as will be seen from Plate XXXIV. The procedure +adopted was to drive a top heading on the center line of each tunnel and +to break down the bench from this. The drilling was at first supplied +with steam power from a temporary plant, as the contractor was at that +time installing his permanent plant, which was finished at the end of +November, 1904. At this time the rate of advance averaged 3½ lin. ft. +of full section per day of 24 hours. By the end of January the Weehawken +rock tunnels were completely excavated, and by the middle of April, +1905, the excavation for the shield chambers was finished; the erection +of the shields was started at the end of that month. + +TABLE 11. + + ==================+=========+========+=============+========+========== + Grade. |Total No.|Rate per|Drilling and |Mucking:|Timbering: + | | day. |blasting: No.| No. | No. + ------------------+---------+--------+-------------+--------+---------- + Superintendent | 1 | $7.70 | ½ | 1/8 | 3/8 + Assistant engineer| 1 | 5.80 | ½ | 1/8 | 3/8 + Electrician | 1 | 3.50 | ½ | 1/8 | 3/8 + Engineer | 1 | 3.50 | | 1 | + Signalman | 1 | 2.00 | | 1 | + Foreman | 3 | 4.00 | 1 | 1 | 1 + Driller | 5 | 3.00 | 5 | | + Driller's helper | 5 | 2.00 | 5 | | + Laborers | 14 | 2.00 | | 14 | + Timbermen | 3 | 3.00 | | | 3 + " helpers | 4 | 2.00 | | | 4 + Machinist | 1 | 4.00 | 1 | | + Blacksmith | 2 | 3.50 | 2 | | + " helper | 2 | 2.00 | 2 | | + Nipper | 2 | 2.00 | 2 | | + Waterboy | 1 | 2.00 | 1 | | + ------------------+---------+--------+-------------+--------+--------- + Total | 47 | | 20½ | 17-3/8 | 9-1/8 + ==================+=========+========+=============+========+========= + +The general scheme of excavation is shown by Plate XXXIII. The bench was +kept 50 or 60 ft. behind the face of the heading. The powder used was +60% Forcite. The general system of drilling was as shown in Fig. 7. The +average length of hole drilled per cubic yard of excavation was 2.9 ft., +as against 7.70 ft. at Manhattan; and the amount of powder used was 1.96 +lb. per cu. yd., as against 1.24 lb. at Manhattan. There was little +timbering. A length of about 30 or 40 ft. adjoining the Weehawken shaft +was timbered, and also a shattered seam of about 17 ft. in width between +Stations 262 + 10 and 262 + 27. + +[Illustration: LAND TUNNELS TYPICAL METHOD OF DRILLING USED IN THE +WEEHAWKEN TUNNELS FIG. 7] + +The two entirely separate tunnels gave a cross-section which was much +more easily timbered than the wide flat span at Manhattan, and the +segmental timbering was amply strong without posts or other +reinforcement. + +Table 12 is a summary of the cost of excavating the Land Tunnels, based +on actual records carefully kept throughout the work. + +TABLE 12.--COST OF EXCAVATION OF LAND TUNNELS, IN DOLLARS PER CUBIC +YARD. + + ======================================+=========+=========+============= + | | |Total yardage + | | | and + |Manhattan|Weehawken|average cost. + --------------------------------------+---------+---------+------------- + Cubic yards excavated |43,289 | 8,311 | 51,600 + _Labor._ | | | + Surface transport | $0.49| $0.87| $0.55 + Drilling and blasting | 2.37| 1.55| 2.24 + Mucking | 2.49| 2.08| 2.42 + Timbering | 0.87| 0.18| 0.76 + --------------------------------------+---------+---------+------------- + Total labor | $6.22| $4.68| $5.97 + --------------------------------------+---------+---------+------------- + _Material._ | | | + Drilling | $0.15| $0.15| $0.15 + Blasting | 0.21| 0.21| 0.21 + Timber | 0.39| 0.20| 0.36 + --------------------------------------+---------+---------+------------- + Total material | $0.75| $0.56| $0.72 + --------------------------------------+---------+---------+------------- + Plant running | $0.76| $0.65| $0.74 + Surface labor, repairs and maintenance| 0.15| 0.08| 0.14 + Field office administration | 1.05| 1.18| 1.07 + --------------------------------------+---------+---------+------------- + Total field charges | $8.96| $7.15| $8.64 + --------------------------------------+---------+---------+------------- + Chief office administration | $0.34| $0.38| $0.34 + Plant depreciation | 0.66| 1.01| 0.72 + Street and building repairs | 0.27| | 0.23 + --------------------------------------+---------+---------+------------- + Total average cost per cubic yard | $10.23| $8.54| $9.93 + ======================================+=========+=========+============= + +Masonry Lining of Land Tunnels. + +Plates XXXII and XXXIV show in detail the tunnels as they were actually +built. It will be seen that in all work, except in the Gy-East contract, +there was a bench at each side of each tunnel in which the cable +conduits were embedded. In Gy-East the bank of ducts which came next to +the middle wall was carried below subgrade, and the inner benches were +omitted. + +The side-walls and subgrade electric conduits were water-proofed with +felt and pitch. The water-proofing was placed on the outside of the +side-walls (that is, on the neat line), and the space between the rock +and the water-proofing was filled with concrete. This concrete was +called the "Sand-Wall." + +The general sequence of building the masonry lining is shown in Fig. 8. +The operations were as follows: + + 1.--Laying concrete for the whole height of the + sand-walls, and for the floor and foundations for + walls and benches up to the level of the base of + the conduits; + + 2.--Water-proofing the side-walls, and, where there was + a middle trench containing subgrade conduits, + laying and water-proofing these conduits; + + 3.--Building concrete wall for conduits to be laid + against, and, where there was a middle trench, + filling up with concrete between the conduits; + + 4.--Laying conduits; + + 5.--Laying concrete for benches and middle-wall; + + 6.--Building haunches from top of bench to springing of + brick arch; + + 7.--Building brick arch and part of concrete + back-filling; + + 8.--Finishing back-filling. + +The whole work will be generally described under the headings of +Concrete, Brickwork, Water-proofing, and Electric Conduits. + +_Concrete._--The number of types and the obstructions caused by the +heavy posting of the timbering made it inadvisable to use built-up +traveling forms at the Manhattan side, though they were used in the +Weehawken Rock Tunnels. + +The specifications required a facing mixture of mortar to be deposited +against the forms simultaneously with the placing of the concrete. This +facing mixture was dry, about 2 in. thick, and was kept separate from +the concrete during the placing by a steel diaphragm. The diaphragm was +removed when the concrete reached the top of each successive layer, and +the facing mixture and concrete were then tamped down together. This +method was at first followed and gave good results, which was indeed a +foregone conclusion, as the Weehawken shaft had been built in this way. +However, it was found that as good results, in the way of smooth finish, +were to be obtained without the facing mixture by spading the concrete +back from the forms, so that the stone was forced back and the finer +portion of the mixture came against the forms; this method was followed +for the rest of the work. All corners were rounded off on a 1-in. radius +by mouldings tacked to the forms. The side-bench forms were used about +four times, and were carefully scraped, planed, filled at open joints, +and oiled with soap grease each time they were set up. When too rough +for face work they were used for sand-wall and other rough work. + +The mixing was done by a No. 4 Ransome mixer, driven by 30-h.p. electric +motors. The mixer at Manhattan was set on an elevated platform at the +north end of the intercepting arch; that at Weehawken was placed at the +entrance to the tunnels. The sand and stone were stored in bins above +the mixers, and were led to the hoppers of the mixers through chutes. +The hoppers were divided into two sections, which gave the correct +quantities of sand and stone, respectively, for one batch. The water was +measured in a small tank alongside. A "four-bag" batch was the amount +mixed at one time, that is, it consisted of 4 bags of cement, 8¾ cu. +ft. of sand, and 17½ cu. ft. of broken stone, and was called a 1 : +2½ : 5 mixture. It measured when mixed about ¾ cu. yd. + +The cement was furnished to the contractor by the Railroad Company, +which undertook all the purchasing from the manufacturer, as well as the +sampling, testing, and storing until the contractor needed it. The +Railroad Company charged the contractor $2 a barrel for this material. + +The sand was required by the specifications to be coarse, sharp, and +silicious, and to contain not more than 0.5% of mica, loam, dirt, or +clay. All sand was carefully tested before being used. The stone was to +be a sound trap or limestone, passing a 1½-in. mesh and being +retained on 3/8-in. mesh. The contractor was allowed to use a coarser +stone than this, namely, one that had passed a 2-in. and was retained on +a 1½-in. mesh. + +The concrete was to be machine-mixed, except in cases of local +necessity. The quantity of water used in the mixture was to be such that +the concrete would quake on being deposited, but the engineer was to use +his discretion on this point. Concrete was to be deposited in such a +manner that the aggregates would not separate. It was to be laid in +layers, not exceeding 9 in. in thickness, and thoroughly rammed. When +placing was suspended, a joint was to be formed in a manner satisfactory +to the engineer. Before depositing fresh concrete, the entire surface on +which it was to be laid was to be cleaned, washed and brushed, and +slushed over with neat cement grout. Concrete which had begun to set was +not to be used, and retempering was not to be allowed. + +[Illustration: MANHATTAN TYPES FIG. 8.] + +The forms were to be substantial and hold their shape until the concrete +had set. The face forms were to be of matched and dressed planking, +finished to true lines and surfaces; adequate measures were to be taken +to prevent concrete from adhering to the forms. Warped or distorted +forms were to be replaced. Plastering the face was not allowed. Rock +surfaces were to be thoroughly washed and cleaned before the concrete +was deposited. + +These specifications were followed quite closely. + +A typical working gang, as divided among the various operations, is +shown below: + + _Superintendence._ + ½ Superintendent @ $250 per month + ½ Assistant engineer " 150 " " + 1 Assistant superintendent " 150 " " + _Surface Transport._ + 1 Foreman @ $2.50 per day + 1 Engineer " 3.00 " " + 1 Signalman " 2.00 " " + 16 Laborers " 1.75 " " + 3 Teams " 7.50 " " + _Laying._ + 1 Foreman @ $4.00 per day + 8 Laborers " 2.00 " " + _Forms._ + 1 Foreman @ $4.50 per day + 4 Carpenters " 3.25 " " + 5 Helpers " 2.25 " " + _Tunnel Transport._ + ¼ Foreman @ $3.25 per day + ¼ Engineer " 3.00 " " + ¼ Signalman " 2.00 " " + 4 Laborers " 1.75 " " + _Mixers._ + ¼ Foreman @ $3.25 per day + 2 Laborers " 1.75 " " + +The superintendent and assistant engineer looked after the brickwork and +other work as well as the concrete. The surface transport gang handled +all the materials on the surface, including the fetching of the cement +from the cement warehouses. + +The tunnel transport gang handled all materials in the tunnel, but, when +the haul became too long, the gang was reinforced with laborers from the +laying gang. Of the laying gang, two generally did the spading, two the +spreading and tamping, and the remaining force dumped the concrete. The +general cost of this part of the work is shown in Table 13. + +The figures in Table 13 include the various items built into the +concrete and some that are certificate extras in connection with the +concrete, such as drains, ironwork and iron materials, rods and bars, +expanded metal, doors, frames and fittings, etc. + +_Water-proofing._--According to the specifications, the water-proofing +was to consist of seven layers of pitch and six layers of felt on the +side-walls and a ½-in. layer of mastic, composed of coal-tar and +Portland cement, to be plastered over the outside of the arches. + +By the time the work was in hand, some distrust had arisen as to the +efficiency of this mastic coating, and a great deal of study was devoted +to the problem of how to apply a felt and pitch water-proofing to the +arches. The difficulty was that there was no room between the rock and +the arch or between the timber and the arch (as the case might be) in +which to work. Several ingenious schemes of putting the felt on in +layers, or in small pieces like shingles, were proposed and discussed, +and a full-sized model of the tunnel arch was even built on which to try +experiments, but it was finally decided to overcome the difficulty by +leaving out the arch water-proofing altogether, and simply building in +pipes for grouting through under pressure, in case it was found that the +arch was wet. + +As to the arch built through the length excavated by cut-and-cover on +the New York side, it was resolved to water-proof that with felt and +pitch exactly as the side-walls were done, the spandrel filling between +the arches being raised in a slight ridge along the concrete line +between tunnels in order to throw the water over to the sides. The +portions of arch not water-proofed were rather wet, and grouting with a +1:1 mixture was done, but only with the effect of stopping large local +leaks and distributing a general dampness over the whole surface of the +arch. + +TABLE 13.--COST OF CONCRETE IN LAND TUNNELS, IN DOLLARS PER CUBIC YARD. + + =======================================+==========+==========+========== + | | | Total + |Manhattan.|Weehawken.| yardage. + ---------------------------------------+----------+----------+---------- + Cubic yards placed |14,706½ | 3,723 |18,429½ + ---------------------------------------+----------+----------+---------- + LABOR. | Average Cost per Cubic Yard. + ---------------------------------------+----------+----------+---------- + Surface transport | $0.31 | $1.43 | $0.54 + Superintendence and general labor at | | | + point of work | 0.31 | 1.31 | 0.51 + Mixing | 0.52 | 0.56 | 0.53 + Laying | 1.38 | 1.45 | 1.39 + Tunnel transport | 1.30 | 1.47 | 1.34 + Cleaning | 0.21 | | 0.17 + Forms: erecting and removal | 1.58 | 1.51 | 1.56 + ---------------------------------------+----------+----------+---------- + Total labor | $5.61 | $7.73 | $6.04 + ---------------------------------------+----------+----------+---------- + MATERIAL. + ---------------------------------------+----------+----------+---------- + Cement | $2.30 | $2.22 | $2.28 + Sand | 0.34 | 0.40 | 0.36 + Stone | 0.91 | 0.61 | 0.85 + Lumber for forms | 0.47 | 0.45 | 0.47 + Sundry tunnel supplies | 0.16 | 0.17 | 0.16 + ---------------------------------------+----------+----------+---------- + Total materials | $4.18 | $3.85 | $4.12 + ---------------------------------------+----------+----------+---------- + Plant running | $0.44 | $0.44 | $0.44 + Surface labor, repairs and maintenance | 0.25 | 1.24 | 0.44 + Field office administration | 0.50 | 1.72 | 0.75 + ---------------------------------------+----------+----------+---------- + Total field charges | $10.98 | $14.98 | $11.79 + ---------------------------------------+----------+----------+---------- + Plant depreciation | $0.62 | $1.57 | $0.81 + Chief office administration | 0.24 | 0.31 | 0.25 + ---------------------------------------+----------+----------+---------- + Total average cost per cubic yard | $11.84 | $16.86 | $12.85 + ---------------------------------------+----------+----------+---------- + Cost of Miscellaneous Items in Concrete. + ---------------------------------------+----------+----------+---------- + |Manhattan.|Weehawken.| Average. + Cubic yards |14,706½ | 3,723 |18,429½ + Amount, in dollars |$6,184.83 | $1,756.79|$7,941.62 + Unit cost | 0.42 | 0.47| 0.43 + =======================================+==========+==========+========== + +The 24-ft. 6-in. tunnel adjoining the Terminal Station-West was +water-proofed by a surface-rendering method which, up to the present +time, has been satisfactory. Generally speaking, the arches of the Land +Tunnels, though not dripping with water, are the dampest parts of the +whole structure from Tenth Avenue to Weehawken, and it would seem as if +some form of water-proofing over these arches would have been a distinct +advantage. + +There was no difficulty in applying the water-proofing on the +side-walls, after a little experience had been gained as to the best +methods. The specifications required the sand-wall to be covered with +alternate layers of coal-tar pitch and felt, seven layers of the former +and six layers of the latter, the felt to be of Hydrex brand or other +equally satisfactory to the engineer. The pitch was to be straight-run, +coal-tar pitch which would soften at 60° Fahr., and melt at 100° Fahr., +being a grade in which distillate oils, distilled from it, should have a +specified gravity of 1.105. The pitch was to be mopped on the surface to +a uniform thickness of 1/16 in., and a covering of felt, previously +mopped with pitch, was to be applied immediately. The sheets were to lap +not less than 4 in. on cross-joints and 12 in. on longitudinal joints, +and had to adhere firmly to the pitch-covered surface. This layer was +then to be mopped, and another layer placed, and so on until all the +layers were in place. This water-proofing was to extend from the bottom +of the cable conduits to the springing of the brick arch. Where +sub-track conduits were used, these were to be surrounded with their own +water-proofing. The work was carried out as specified; the sand-walls +were not rendered, but were built smooth enough to apply the +water-proofing directly to them. They were dried with gasoline torches +before the application of the pitch, and in very wet sections grooves +were cut to lead the water away. + +The first attempts were with the felt laid in horizontal strips. This +ended very disastrously, as the pitch could not sustain the weight of +the felt, and the whole arrangement slipped down the wall. The felt was +then laid vertically, being tacked to a piece of horizontal scantling at +the top of the sand-wall and also held by a row of planks braced +against it at about half its height. A layer of porous brick was laid as +a drain along the base of the water-proofing, covered by a single layer +of felt to prevent it from becoming choked with concrete. + +The water-proofing of the sub-track conduits was troublesome, as the +numerous layers and the necessity for preserving the proper laps in both +directions between adjacent layers made the whole thing a kind of +Chinese puzzle. Various modifications, to suit local conditions, were +made from time to time. Conduits outside the general outline of the +tunnel are difficult to excavate, to lay, and to water-proof, and should +be avoided wherever possible. + +The usual force in water-proofing consisted of a foreman, at $3.50 per +day, and nine laborers at $1.75 per day. These men not only laid the +water-proofing, but transported the materials, heated the pitch, and cut +up the rolls of felt. In general, two men transported material, one +tended the heater, and the other six worked in pairs, two preparing the +surface of the concrete sand-wall, two laying pitch, and two laying +felt. + +The cost of the water-proofing operation was about as shown in Table 14. + +TABLE 14.--COST OF WATER-PROOFING, IN DOLLARS PER SQUARE FOOT. + + =======================================+==========+===========+======== + |Manhattan.| Weehawken.| Total. + ---------------------------------------+----------+-----------+-------- + Square feet covered | 47,042 | 13,964 | 60,736 + ---------------------------------------+----------+-----------+-------- + Average cost per square foot. + ---------------------------------------+----------+-----------+-------- + Labor | $0.07 | $0.07 | $0.07 + Material | 0.12 | 0.09 | 0.11 + ---------------------------------------+----------+-----------+-------- + Total field charges | $0.19 | $0.16 | $0.18 + Chief office and plant depreciation | 0.01 | 0.03 | 0.02 + ---------------------------------------+----------+-----------+-------- + Total average cost | $0.20 | $0.19 | $0.20 + =======================================+==========+===========+======== + +_Brickwork in Arches._--Owing to the heavy timbering, the brickwork at +Manhattan was interfered with to a considerable extent, and the gang was +always kept at work at two or more places. The work was carried up to a +point where it was necessary to back-fill, or prop or cut away +encroaching timbers, and then the men were moved to another place while +this was being done. + +The centers were set up in sets of seven, spaced 4 ft. apart. Two +14-ft. lengths of 3 by 4-in. yellow pine lagging were used with each set +of ribs, with 24 by 8-in. block lagging in the crown. + +All centers were set ¼ in. high, to allow for settlement, except in +the 24-ft. 6-in. span, in which they were set ½ in. high. This proved +ample, the average settlement of the ribs being 0.01 ft. and of the +masonry, 0.003 ft. In the 24-ft. 6-in. span the ribs were strengthened +with 6 by 6-in. blocking and 12 by 12-in. posts to subgrade. Great +trouble was here encountered with encroaching timbering, due to the +settlement of the wide flat span. Grout pipes were built in, as +previously mentioned. + +Each mason laid an average of 0.535 cu. yd. of brickwork per hour, or +4.28 cu. yd. per day. The number of bricks laid per mason per hour was +218, or 1,744 per day. + +The bricks were of the best quality of vitrified paving brick, and were +obtained from the Jamestown Brick Company, of Jamestown, N. Y. The +average size was 8¾ by 3-15/16 by 2-7/16 in.; the average number per +cubic yard of masonry was 408, the arches being from 19 ft. to 24 ft. 6 +in. in span and from 22 to 27 in. thick. The joints were 3/16 in. at the +face and averaged 9/16 in. through the arch. + +The proportions for mortar were 1 of cement and 2½ of sand. One cubic +yard of masonry was composed of 73.5% brick and 26.5% mortar. The volume +of the ingredients in a four-bag batch was 12.12 cu. ft., and the +resulting mixture was 9.54 cu. ft. The number of barrels of cement was +0.915 per cu. yd. of masonry, and about 17.7% of the mortar made was +wasted. The average force employed was: + + _Laying._ + 1 Foreman @ $8.00 per day + 4 Layers " 6.00 " " + 8 Tenders " 2.00 " " + 2 Mixers " 2.00 " " + _Forms._ + 1 Foreman @ $4.50 per day + 4 Carpenters " 3.50 " " + 5 Helpers " 2.25 " " + _Transport._ + ¼ Hoist engineer @ $3.00 per day + ¼ Signalman " 2.00 " " + 4 Laborers " 2.00 " " + +For materials, the following prices prevailed: + + Cement, $2.00 per bbl., + Sand, $0.90 to $1.00 per cu. yd., + Brick, $16.00 per thousand, delivered at yard, + Centers, $26.00 each, + Lagging, $45.00 per 1,000 ft. B. M. + +The cost of the brickwork is given in Table 15. + +TABLE 15.--COST OF BRICKWORK. + + ===========================================+==========+==========+====== + |Manhattan.|Weehawken.|Total. + -------------------------------------------+----------+----------+------ + Cubic yards placed | 4,137 | 790 |4,927 + -------------------------------------------+----------+----------+------ + LABOR. |Average Cost per Cubic Yard. + -------------------------------------------+----------+----------+------ + Surface transport | $0.35 | $1.19 | $0.48 + Superintendent and general labor at point | | | + of work | 0.17 | 0.04 | 0.16 + Laying and mixing | 2.58 | 3.20 | 2.60 + Forms: erection and removal | 2.62 | 0.32 | 2.25 + Tunnel transport | 1.19 | 1.12 | 1.18 + -------------------------------------------+----------+----------+------ + Total labor | $6.91 | $5.87 | $6.75 + -------------------------------------------+----------+----------+------ + MATERIAL. + -------------------------------------------+----------+----------+------ + Brick | $6.56 | $6.56 | $6.56 + Cement | 1.76 | 1.75 | 1.76 + Sand | 0.20 | 0.28 | 0.22 + Forms | 0.92 | 0.98 | 0.98 + Overhead conductor pockets | 0.15 | 0.09 | 0.13 + -------------------------------------------+----------+----------+------ + Total material | $9.59 | $9.66 | $9.60 + -------------------------------------------+----------+----------+------ + Plant running | $0.55 | $0.30 | $0.51 + Surface labor, repairs and maintenance | 0.36 | 1.30 | 0.51 + Field office administration | 0.55 | 0.88 | 0.60 + -------------------------------------------+----------+----------+------ + Total field charges | $17.96 | $18.01 |$17.97 + -------------------------------------------+----------+----------+------ + Chief office administration | $0.60 | $0.66 | $0.61 + Plant depreciation | 0.35 | 0.64 | 0.39 + -------------------------------------------+----------+----------+------ + Total average cost per cubic yard | $18.91 | $19.31 |$18.97 + ===========================================+==========+==========+====== + +In Table 16 the cost of grout is expressed in terms of barrels of cement +used, because in the schedule of prices attached to the contract, that +was the unit of payment for grout. + + TABLE 16.--COST OF GROUT OVER ARCHES IN LAND TUNNELS. + Cost, in Dollars per Barrel of Cement Used. + + ======================================+===============+==========+====== + | Manhattan. | | + |(Gy-East only.)|Weehawken.|Total. + --------------------------------------+---------------+----------+------ + Barrels used | 3,000½ | 261½ |3,262 + --------------------------------------+---------------+----------+------ + Average Cost + per Barrel of Cement Used. + --------------------------------------+---------------+----------+------ + Labor | $0.55 | $0.46 |$0.53 + Material | 2.30 | 2.25 | 2.28 + Field office administration | 0.08 | 0.06 | 0.08 + Plant and supplies | 0.10 | 0.07 | 0.09 + --------------------------------------+---------------+----------+------ + Total field charges | $3.03 | $2.84 |$2.98 + --------------------------------------+---------------+----------+------ + Chief office and plant depreciation | 0.21 | 0.22 | 0.28 + --------------------------------------+---------------+----------+------ + Total average cost | $3.24 | $3.06 |$3.20 + ======================================+===============+==========+====== + +_Vitrified Earthenware Conduits for Electric Cables._--The general +drawings will show how the ducts were arranged, and that manholes were +provided at intervals. They were water-proofed, in the case of those +embedded in the bench, by the general water-proofing of the tunnels, +which was carried down to the level of the bottom of the banks of ducts; +and in the case of those below subgrade, by a special water-proofing of +felt and pitch wrapped around the ducts themselves. + +The portion of wall in front of the ducts was bonded to that behind by +bonds, mostly of expanded metal, passing between the ducts. Examples of +the bonding will be seen in the drawings. + +The joints between successive lengths of 4-way and 2-way ducts were +wrapped with two thicknesses of cotton duck, 6 in. wide, those of +single-way ducts were not wrapped, but plastered with cement mortar. The +ducts were laid on beds of mortar, and were made to break joints at top +and bottom and side to side with the adjacent ducts. They were laid with +a wooden mandrel; a square leather washer at the near end acted as a +cleanser when the mandrel was pulled through. + +The specifications required the ducts to be laid at the same time as the +concrete and be carried up with it, but this was found to be a very +awkward operation, as the tamping of the concrete and the walking of +men disturbed the ducts, especially as the bonds lay across them. It was +resolved, therefore, to build the portion of the wall behind the ducts +first, with the bonds embedded in it at the proper heights and +projecting from it, then to lay up the banks of ducts against this wall, +bending the bonds down as they were reached, and finally, after all the +ducts were in, to lay the concrete in front of and over the top of the +ducts. Several detailed modifications of this general scheme were +followed at one time or another when necessary or advisable. + +The laying of ducts below subgrade was not complicated by the presence +of bonds, the water-proofing caused the trouble here, as before +described. + +The specifications called for a final rodding after completion. A group +of the apparatus used in this process is shown in Fig. 1, Plate XXXV; +the various parts are identified by the following key: + + KEY TO FIG. 1, PLATE XXXV. + + 1.--4-way duct, for telephone and telegraph cables, + 2.--2-way duct, for telephone and telegraph cables, + 3.--1-way duct, for high- and low-tension cables, + 4.--Plug for closing open ends of ducts, + 5.--Plug for closing open ends of ducts in position, + 6, 7, and 8.--Cutters for removing obstructions, + 9.--Hedgehog cutter for removing grout in ducts, + 10.--Rodding mandrel for multiple ducts, + 11.--Laying mandrel, + 12.--Rodding mandrel, with jar-link attached, + 13.--Laying mandrel, + 14 and 15.--Rubber-disk cleaners, used after final + rodding, + 16 and 17.--Sectional wooden rods used for rodding, + 18.--Section of iron rods used for rodding, + 19.--Jar-link, + 20.--Cotton duck for wrapping joints of multiple ducts, + 21.--Hook for pulling forward laying mandrel, + 22.--Top view of trap for recovering lost or broken + rods left in ducts. + +[Illustration: PLATE XXXV. TRANS. AM. SOC. CIV. ENGRS. VOL. LXVIII, No. +1155. HEWETT AND BROWN ON PENNSYLVANIA R. R. TUNNELS: NORTH RIVER +TUNNELS. FIG. 1. FIG. 2.] + +Ordinary ¾-in. gas pipe was used for the rod, and a cutter with +rectangular cross-section and rounded corners was run through ahead of +the mandrel: following the cutter came a scraper consisting of several +square leather washers, of the size of the ducts, spaced at intervals on +a short rod. The mandrel itself was next put through, three or four men +being used on the rods. All the ducts in a bank were thus rodded from +manhole to manhole. When a duct was rodded it was plugged at each end +with a wooden plug. A solid wooden paraffined plug was used at first, +but afterward an expansion plug was used. + +Very little trouble was met in rodding the power conduits, except for a +few misplaced ducts, or a small mound of mortar or a laying mandrel left +in. At such points a cut was made in the concrete and the duct replaced. + +In the subgrade telephone and telegraph ducts east of the Manhattan +Shaft, much trouble was caused by grout in the ducts. The mandrel and +cutters were deflected and broke through the web of the ducts rather +than remove this hard grout. Trenches had to be cut from the floor to +the top of the water-proofing, the latter was then cut and folded back, +and the ducts replaced. To do this, a number of ducts had to be taken +out to replace the broken ones and get the proper laps. The +water-proofing was then patched and the concrete replaced. This grout +had not penetrated the water-proofing, but had got in through the ends +of the ducts where they had not been properly plugged and protected. The +duct gang, both for laying and rodding, generally consisted of + + 1 Foreman, at $3.50 per day, + and 9 laborers, at $1.75 per day. + +When laying: 4 men were laying, 2 men mixing and carrying mortar, and 3 +were transporting material. When rodding: 4 men were rodding, 2 men at +adjacent manholes were connecting and disconnecting cutters and +mandrels, 1 was joining up rods, and 2 men assisting generally. + +The cost of this work is shown in Table 17. + + +Transportation and Disposal. + +The track on the surface and in the tunnels was of 20-lb. rails on a +2-ft. gauge. + +The excavation was handled in scale-boxes carried on flat cars, and the +concrete in 1¼-cu. yd. mining cars dumping either at the side or +end. + +TABLE 17.--COST OF CONDUIT WORK. + + =========================================+==========+==========+======= + |Manhattan.|Weehawken.| Total. + -----------------------------------------+----------+----------+------- + Duct feet | 115,962 | 35,155 |151,117 + -----------------------------------------+----------+----------+------- + Average Cost per Duct Foot. + -----------------------------------------+----------+----------+------- + Labor | $0.035 | $0.032 | $0.034 + Material | 0.043 | 0.052 | 0.045 + -----------------------------------------+----------+----------+------- + Total field charges | 0.078 | 0.084 | 0.079 + -----------------------------------------+----------+----------+------- + Chief office and plant depreciation | 0.005 | 0.008 | 0.006 + -----------------------------------------+----------+----------+------- + Total average cost | $0.083 | $0.092 | $0.085 + =========================================+==========+==========+======= + +When the haulage was up grade, 6 by 6-in. Lidgerwood hoisting engines, +with 10-in. single friction drums, and driven by compressed air from the +high-pressure lines, were used. Down grade, cars were moved and +controlled by hand. + +The muck which came through the shaft at Manhattan was dumped into +hopper bins on the surface and thence loaded into trucks at convenience. +At the open cut, the muck was dumped into trucks direct. The trucking +was sublet by the contractor to a sub-contractor, who provided trucks, +teams, and trimmers at the pier. At Weehawken, arrangements were made +with the Erie Railroad which undertook to take muck which was needed as +fill. The tunnel cars, therefore, were dumped directly on flat cars +which were brought up to a roughly made platform near the shaft. + +The hoisting at Manhattan was by derrick at Tenth Avenue and the open +cut, and by the elevator at the Manhattan Shaft. At Weehawken, all +hoisting was done by the elevator in the shaft. + +The sand and stone were received at the wharves by scows. At Manhattan, +these materials were unloaded on trucks by an overhead traveler, and +teamed to the shaft, where they were unloaded by derricks into the bins. +At Weehawken, they were unloaded by an orange-peel grab bucket, loaded +into cars on the overhead trestle, transported in these to the top of +the shaft, and discharged into the bins. + +The cement at Manhattan was trucked from the Company's warehouse, at +Eleventh Avenue and 38th Street, to the shaft, where it was put into a +supplementary storage shed at the top of the shaft, whence it was +removed to the mixer by the elevator when needed. At Weehawken, it was +taken on flat cars directly from the warehouse to the mixer. + + +Lighting. + +Temporarily and for a short time at the start, kerosene flares were used +for light until replaced by electric lights, the current for which was +furnished by the contractor's generators, which have been described +under the head of "Power Plant." + +The lamps used along the track were of 16 c.p., and were protected by +wire screens; these were single, but, wherever work was going on, groups +of four or five, provided with reflectors, were used. + + +Pumping. + +Two pumps were installed at the Manhattan Shaft. They had to handle the +water, not only from the rock tunnels, but also from those under the +river. One was a Deane compound duplex pump, having a capacity of 500 +gal. per min., the other, a Blake pump, of 150 gal. per min. They were +first driven by steam direct from the power-house, but compressed +air was used later. When the power-house was shut down, an +electrically-driven centrifugal pump was used. This was driven by a +General Electric shunt-wound motor, Type C-07½, with a speed of 1,250 +rev. per min. at 250 volts and 37.5 amperes (10 h.p.) when open, and +22.9 amperes (6 h.p.) when closed, and had a capacity of 450 gal. per +min. To send the water to the shaft sump during the construction, small +compressed-air Cameron pumps, of about 140 gal. per min., were used. + +At the Weehawken shaft two pumps were used; these dealt with the water +from the Bergen Hill Tunnels as well as that from the Weehawken Tunnels. +At first a Worthington duplex pump having a capacity of about 500 gal. +per min. was used. Later, this was replaced by a General Electric +shunt-wound motor, Type O-15, with a speed of 925 rev. per min. at 230 +volts and 74 amperes (20 h.p.) when open, and 38.5 amperes (10 h.p.) +when closed. Its capacity was 240 gal. per min. During the progress of +the construction, the water was pumped from the working face to the +shaft by small Cameron pumps similar to those used at Manhattan. When +the work was finished, a subgrade reversed-grade drain carried the +water to the shaft sump by gravity. + +The work in the Manhattan Land Tunnels was practically finished by May +1st, 1908, though the ventilating arrangements and overhead platform in +the intercepting arch were not put in until after the River Tunnel +concrete was completed, so that the work was not finished until +September, 1909. + +The Weehawken Land Tunnels work was finished in July, 1907, but the +benches and ventilating arrangements in the Weehawken Shaft were not put +in until after the completion of the Bergen Hill Tunnels, and so were +not finished until August, 1909. + +The reinforced concrete wall around the Weehawken Shaft, together with +the stairs from the bench level of the shaft to the surface, was let as +a separate contract; the work was started on September 15th, 1909, and +finished by the end of December, 1909. + + +RIVER TUNNELS. + +The River Tunnel work, from some points of view, has the most interest. +It is interesting because it is the first main line crossing of the +formidable obstacle of the Hudson River, and also by reason of the long +and anxiously discussed point as to whether, in view of the preceding +experiences and failures to construct tunnels under that river, +foundations were needed under these tunnels to keep them from changing +in elevation under the action of heavy traffic. + +The River Tunnels here described start on the east side of the shield +chambers on the New York side and end at the east side of the shield +chambers on the New Jersey side. They thus include the New York and +exclude the New Jersey shield chambers, the reason for such +discrimination being that the New York shield chambers are lined with +cast iron while those on the New Jersey side are of the typical rock +section type, as already described. The design of the tunnels and their +accessories will be first described, then will come the construction of +the tunnels as far as the completion of the metal lining, followed by a +description of the concrete lining and completion of the work. + + +Design of Metal Lining. + +_New York Shield Chambers._--The shield chambers may be seen on Plate +XXXII, previously referred to, which shows the junction of the +iron-lined tunnels and the shield chambers. They consist of two +iron-lined pieces of tunnel placed side by side, with semi-circular +arches and straight side-walls. The segments of the arch are made to +break joint with one another by making the side-wall or column castings +of two different heights, as shown in Fig. 9. The length of each ring is +18 in. + +The reason for the adoption of this type of construction was the +necessity for keeping the width of the permanent structure within the +60-ft. width of the street. The length of this twin structure is 28.5 +ft., and the weight of the metal in it is as follows: + + 19 long-column arch rings at 22,802 lb. 433,238 lb. + 19 short-column arch rings at 23,028 lb. 437,532 " + ------- + Total weight 870,770 lb. + +_General Type of River Tunnel Lining._--The main ruling type adopted for +the tunnels under the Hudson River, and in the soft water-bearing ground +for some distance on the shoreward side of the river lines, consists of +two parallel metal-lined tunnels, circular in cross-section, each tunnel +being 23 ft. outside diameter, and the two tunnels 37 ft. apart from +center to center, as shown on Fig. 10. The metal lining is of cast iron +(except for a few short lengths of cast steel) and of the usual +segmental type, consisting of "Rings" of iron, each ring being 2 ft. 6 +in. in length, and divided by radial joints into eleven segments, or +"Plates," with one "Key," or closing segment, having joints not radial +but narrower at the outside circumference of the metal lining than at +the inside. The whole structure is joined, segment to segment, and ring +to ring, by mild-steel bolts passing through bolt holes in flanges of +all four faces of each segment. The joints between the segments are made +water-tight by a caulking of sal-ammoniac and iron borings driven into +grooves formed for the purpose on the inner edges of the flanges. The +clearances between the bolts and the bolt holes are also made +water-tight by using grummets or rings of yarn smeared with red lead, +having a snug fit over the shank of the bolt and placed below the washer +on either end of each bolt. When passing through ground more or less +self-sustaining, the space outside the iron lining (formed by the +excavation being necessarily rather larger than the external diameter of +the lining itself) was filled with grout of 1:1 Portland cement and sand +forced by air pressure through grout holes in each segment. These holes +were tapped, and were closed with a screw plug before and after +grouting. + +[Illustration: DETAILS OF MANHATTAN SHIELD CHAMBERS FIG. 9.] + +Having thus stated in a general way the main ruling features of the +design, a detailed description of the various modifications of the +ruling type will be given. + +[Illustration: TYPICAL CROSS-SECTION OF RULING DESIGN OF METAL-LINED +SHIELD-DRIVEN TUNNELS FIG. 10.] + +The two main divisions of the iron lining are the "ordinary" or lighter +type and the heavy type. The details of the ordinary iron are shown in +Fig. 11, which shows all types of lining. It was on this design that the +contract was let, and it was originally intended that this should be the +only type of iron used. The dimensions of the iron are clearly shown on +the drawing, and it will be seen that the external diameter is 23 ft., +the interior diameter, 21 ft. 2 in., the length of each ring, 2 ft. 6 +in., and the thickness of the iron skin or web, 1½ in. The bolt holes +in the circumferential flanges are evenly spaced through the circle, so +that adjacent rings may be bolted together in any relative position as +regards the radial joints, and, as a matter of fact, in the erection of +the tunnel lining, all the rings "break joint," with the exception of +those at the bore segments, as will be described later. This type of +iron, when the original type was modified, came to be known as the +ordinary pocketless iron; that is, the weight is of the ordinary or +lighter type, in contradistinction to the heavier one, which later +supplanted it, and the caulking groove runs along the edges of the +flanges and does not form pockets around the bolt holes, as did the +groove in a later type. + +Each ring is made up of eleven segments and a key piece. Of these, nine +have radial joints at both ends, and are called "_A_" segments; two, +called "_B_" segments, have a radial joint at one end and a non-radial +joint at the other. The non-radial joint is placed next to the key, +which is 12.25 in. wide at the outside circumference of the iron and +12.50 in. wide at the inside. + +The web is not of uniform thickness. The middle part of each _A_ and _B_ +segment is 1½ in. thick; at the distance of 6 in. from the root of +each flange, the thickness of web begins to increase, so that at the +root it is 2-3/8 in. thick. The web of the key plate is 1¾ in. thick. + +The bolts are of mild steel, and are 1½ in. in diameter; there are 67 +in one circumferential joint and 5 in each radial joint. As there are 12 +such radial joints, there are altogether 60 bolts in the cross-joints, +making a total of 127 bolts per ring. + +This original type of ordinary iron was modified for a special purpose +as follows: It was known that for some distance on either side of the +river, and especially at Weehawken, the tunnels would pass through a +gravel formation, rather open, and containing a heavy head of water. It +was thought that, by carrying the caulking groove around the bolt holes, +it would be possible to make them more water-proof than by the simple +use of the red-leaded grummets. Hence the "Pocket Iron" was adopted for +this situation, the name being derived from the pocket-like recess which +the caulking groove formed when extended around the bolt hole. The +details of this lining are shown on Fig. 11, and the iron (except for +the pockets) is exactly like the pocketless type. + +[Illustration: DETAILS OF ALL TYPES OF METAL LININGS USED IN SUBAQUEOUS +SHIELD-DRIVEN TUNNELS FIG. 11.] + +On the New York side, in both North and South Tunnels, two short lengths +were built with cast-steel lining. This was done where unusual stresses +were expected to come on the lining, namely, at the point where the +invert passed from firm ground to soft, and also where the tunnels +passed under the heavy river bulkhead wall. + +The design was precisely the same as for the ordinary pocketless iron, +and Fig. 11 shows the details. After the tunnels had entered into the +actual under-river portion, several phenomena (which will be described +later) led to the fear that the tunnels, being lighter than the +semi-liquid mud they displaced, might be subject to a buoyant action, +and therefore a heavier type of lining was designed. The length of ring, +number of bolts, etc., were just the same as for the lighter iron, but +the thickness of the web was increased from 1½ to 2 in., the +thickness of the flanges was proportionately increased, and the diameter +of the bolts was increased from 1½ to 1¾ in. This iron was all of +the pocketless type, shown in Fig. 11. Table 18 gives the weights of the +various types of lining. + +TABLE 18.--WEIGHTS OF TUNNEL LINING, DIAMETER AND WEIGHTS OF BOLTS, ETC. + + +=========+===============+========+========+=======+========+========| + |Reference|Type of Lining.| Weight | Weight |Weight | Weight |Diameter| + |No. | | of one | of one |of one | of one | of | + | | | "A" | "B" |key, in|complete| bolts, | + | | |Segment,|Segment,|pounds.|ring, in| in | + | | | in | in | |pounds. |inches. | + | | |pounds. |pounds. | | | | + | | | | | | | | + | | | | | | | | + | | | | | | | | + | | | | | | | | + |---------+---------------+--------+--------+-------+--------+--------| + |1 |Ordinary cast | 2,063 | 2,068 | 480 | 23,183 | 1½ | + | |iron without | | | | | | + | |caulking | | | | | | + | |pockets. | | | | | | + |2 |Ordinary cast | 2,038 | 2,043 | 469 | 22,897 | 1½ | + | |iron with | | | | | | + | |caulking | | | | | | + | |pockets. | | | | | | + |3 |Ordinary cast | 2,247 | 2,252 | 522 | 25,249 | 1½ | + | |steel without | | | | | | + | |caulking | | | | | | + | |pockets. | | | | | | + |4 |Heavy cast iron| 2,579 | 2,584 | 606 | 28,985 | 1¾ | + | |without | | | | | | + | |caulking | | | | | | + | |pockets. | | | | | | + +---------+---------------+--------+--------+-------+--------+--------+ + + +=========+===============+========+=======+=========+ + |Reference|Type of Lining.| Weight |Weight | Total | + |No. | | of 1 | of |weight of| + | | | bolt, |bolts, |one ring | + | | |nut, and| nuts, |(segments| + | | | 2 | and | and | + | | |washers,|washers| bolts), | + | | | in | per | in | + | | |pounds. | ring, | pounds. | + | | | | in | | + | | | |pounds.| | + |---------+---------------+--------+-------+---------| + |1 |Ordinary cast | 6.62 | 840.7 | 24,024 | + | |iron without | | | | + | |caulking | | | | + | |pockets. | | | | + |2 |Ordinary cast | 6.62 | 840.7 | 23,738 | + | |iron with | | | | + | |caulking | | | | + | |pockets. | | | | + |3 |Ordinary cast | 6.62 | 840.7 | 26,090 | + | |steel without | | | | + | |caulking | | | | + | |pockets. | | | | + |4 |Heavy cast iron| 10.50 |1,333.5| 30,319 | + | |without | | | | + | |caulking | | | | + | |pockets. | | | | + +---------+---------------+--------+-------+---------+ + + + WEIGHTS OF VARIOUS TYPES OF LINING PER LINEAR FOOT OF TUNNEL. + + +---------+---------------+--------------+-------------+---------------+ + |Reference|Type of Lining.|Weights of |Weights of |Weights of | + |No. | |complete rings|bolts, nuts, |segments and | + | | |(segments |and washers, |bolts in tunnel| + | | |only), in |in pounds. |complete, in | + | | |pounds. | |pounds. | + |---------+---------------+--------------+-------------+---------------| + |1 |Ordinary cast | 9,273.0 | 336.3 | 9,609.6 | + | |iron without | | | | + | |pockets. | | | | + | | | | | | + |2 |Ordinary cast | 9,158.8 | 336.3 | 9,495.2 | + | |iron with | | | | + | |pockets. | | | | + | | | | | | + |3 |Ordinary cast | 10,099.6 | 336.3 | 10,436.0 | + | |steel without | | | | + | |pockets. | | | | + | | | | | | + |4 |Heavy cast iron| 11,594.0 | 533.4 | 12,127.6 | + | |without | | | | + | |pockets. | | | | + +=========+===============+==============+=============+===============+ + +The weights in Table 18 are calculated by assuming cast iron to weigh +450 lb. per cu. ft., and cast steel 490 lb. In actual practice the +"ordinary" iron was found to weigh a little more than the weights given, +and the "heavy" a little less. + +The silt in the sub-river portion averaged about 100 lb. per cu. ft., so +that the weight of the silt displaced by the tunnel was about 41,548 lb. +per lin. ft. + +_Taper Rings._--In order to pass around curves (whether horizontal or +vertical), or to correct deviation from line or grade, taper rings were +used; by this is meant rings which when in place in the tunnels were +wider than the standard rings, either at one side (horizontal tapers or +"Liners"), or at the top ("Depressors"), or at the bottom ("Elevators"). + +In the original design a ½-in. taper was called for, that is, the wide +side of the ring was ½ in. wider than the narrow side, which was of +the standard width of 2 ft. 6 in. As a matter of fact, during +construction, not only ½-in., but ¾-in. and 1-in. tapers were often +used. + +These taper rings necessitated each plate having its own unalterable +position in the ring, hence each plate of the taper ring was numbered, +so that no mistake could be made during erection. + +The taper rings were made by casting a ring with one circumferential +flange much thicker than usual, and then machining off this flange to +the taper. This was not only much cheaper than making a special pattern +for each plate, but made it possible to see clearly where and what +tapers were used in the tunnel. + +Taper rings were provided for all kinds of lining (except the cast +steel), and the lack of taper steel rings was felt when building the +steel-lined parts of the tunnel, as nothing could be done to remedy +deviations from line or grade until the steel section was over and cast +iron could again be used. Table 19 gives the weights of the different +kinds of tapers used. + +TABLE 19.--WEIGHTS OF CAST-IRON TAPER RINGS, IN POUNDS PER COMPLETE +RING. + + =================================+====================================== + Classification. |Weight of cast iron per complete ring, + | in pounds. + ---------------------------------+-------------------------------------- + Ordinary pocketless ½- in. taper| 23,767.7 + " " 1- " " | 24,352.4 + " pocket ½- " " | 23,481.7 + Heavy pocketless ½- in. taper | 29,564.8 + " " ¾- " " | 29,854.7 + " " 1- " " | 30,144.6 + =================================+======================================= + +_Cast-Steel Bore Segments and Accessories._--The following feature of +these tunnels is different from any hitherto built. It was the original +intention to carry the rolling load independent of the tunnel, or to +assist the support of the silt portion of the structure by a single row +of screw-piles, under each tunnel, and extending down to firmer ground +than that through which the tunnels were driven. Therefore, provision +had to be made whereby these piles could be put down through the invert +of the tunnel with no exposure of the ground. + +[Illustration: DETAILS OF BORE SEGMENTS AND ACCESSORIES USED IN +SUBAQUEOUS SHIELD DRIVEN TUNNELS FIG. 12.] + +This provision was afforded by the "Bore Segments," which are shown in +detail in Fig. 12. There are two segments, called No. 1 and No. 2, +respectively. These two segments are bolted together in the bottom of +two adjacent rings, and thus form a "Pile Bore." As the piles were to be +kept at 15-ft. centers, and as the tunnel rings were 2 ft. 6 in. in +length, it will be seen that, between each pair of bore-segment rings, +there came four "Plain" rings. The plain rings were built up so that the +radial joints broke joint from ring to ring, but with the bore-segment +rings this could not be done, without unnecessarily adding to the types +of segments. + +The bore segments were made of cast steel, and were quite complicated +castings, the principle, however, was quite simple. The segments +provided an opening just a little larger than the shaft of the pile, the +orifice being 2 ft. 7 in. in diameter at the smallest (lowest) point, +while the shaft of the pile was to be 2 ft. 5¼ in. In order to allow +of the entry of the screw-blade or helix of the pile, a slot was formed +in the depth of Bore Segment No. 1, so that, when a pile was put in +position above the bore, the blade, when revolved, would enter the slot +and thus pass under the metal lining, although the actual orifice was +only slightly larger than the pile shaft. + +The wall of the pile orifice in Segment No. 2 was made lower than that +in No. 1 so as to allow the blade to enter the slot in Segment No. 1. +When the pile is not actually in process of being sunk, this lower +height in No. 2 is made up with the removable "distance piece." This had +a tongue at one end which engaged in a recess cast to take it in Segment +No. 2 and was held in place by a key piece at the other end of the +distance piece. Details of the distance piece and key are shown in Fig. +12. + +The flanges around the pile bore were made flat and furnished with +twelve tapped holes, six in Segment No. 1 and six in Segment No. 2, for +the purpose of attaching the permanent arrangements in conjunction with +which the pile was to be attached to the track system, independently of +the tunnel shell, or directly to the tunnel. It was never decided which +of these alternatives would be used, for, before this decision was +reached, it was agreed that, at any rate for the present, it was better +not to put down piles at all. + +To close the bore, the "Bore Plug" was used. This is shown on Fig. 12. +It was of cast steel, and was intended to act as a permanent point of +the screw-pile, that is, the blade section was to be attached to the +bore plug, the distance piece and key were to be removed, and the pile +was to be rotated until the blade had cleared the slot; the distance +piece and key were then to be replaced and sinking resumed. + +The plug was held in place against the pressure of the silt by the two +"dogs," while the dogs themselves were attached to the tunnel, as shown +in Fig. 12. The ends of the dogs, which rested on the flanges of the +metal lining of the tunnel, were prevented from being knocked off the +flanges (and thus releasing the plug) by steel clips. + +It was expected that it might be desirable to keep the lower end of the +piles open during their sinking, so that the bore plugs were not made +permanently closed, but a seating was formed on the inner circumference +of the plug, and on the seating was placed the "Plug Cover," made of +cast iron, 18¾ in. in diameter and 3 in. thick, furnished with a lug +for lifting and a 3-in. tapped hole closed by a screw-plug, through +which any soundings or samples of ground could be taken prior to sinking +the piles. This plug cover was held in place by a heavy steel "Yoke" +under it, which engaged on the under side of the flange, on top of which +the cover was set. The yoke was attached to the cover by a 1¾-in. +tap-bolt, screwed into the yoke and passing through a 2-in. hole bored +in the center of the cover. This rather peculiar mode of attaching the +cover was adopted so that the cover could be removed by taking off the +nut of the yoke, in case it was desired to open the end of the pile +during the process of sinking. + +The plug was a fairly close fit at the bottom of the orifice, that is, +at the outside circumference of the tunnel, where the bore was 2 ft. 7 +in. in diameter and the plug 2 ft. 6¾ in., but at the top of the +bore-segment there was more clearance, as the plug was cylindrical while +the bore tapered outward. To fill this space, it was intended that steel +wedges should be used while the shield was being driven, so that they +would withstand the crushing action of the thrusting shield, and, when +the shield was far enough ahead, that they should be removed and +replaced by hardwood wedges. This method was only used in the early +weeks of the work; the modification of not using the shield-jacks which +thrust against the bore segments was then introduced, and the wooden +wedges were put in, when the bore plugs were set in place, and driven +down to the stage of splitting. + +When it was resolved not to sink the screw-piles, the bores had to be +closed before putting in the concrete lining. This was done by means of +the covers shown in Fig. 13. The bore plug and all its attachments were +removed, and the flat steel cover, 2 in. thick and with stiffening webs +on the under side, was placed over the circular flanges of the pile +bore. The cover was attached to the bore segments by twelve 1½-in. +stud-bolts, 6 in. long, in the bolt holes already mentioned as provided +on these flanges. + +When these were in place, with lead grummets under the heads of the +bolts, and the grooves caulked, the bore segments were water-tight, +except in Bore Segment No. 2, at the joint of the distance piece; and, +to keep water from entering here, this segment was filled to the level +of the top of the flanges with 1:1 Portland cement mortar. + +[Illustration: SUBAQUEOUS TUNNELS COVER FOR BORE SEGMENTS FIG. 13.] + +The weights of the various parts of the bore segments are given in Table +20. + +TABLE 20.--WEIGHTS OF BORE SEGMENTS AND ACCESSORIES, IN POUNDS. + + ====================+=====+==================================== + Part. | No. | Material. | Weight, in pounds. + --------------------+-----+---------------+-------------------- + Bore Segment No. 1 | 1 | Cast Steel | 3,004.0 + Bore Segment No. 2 | 1 | " " | 2,628.0 + Distance piece | 1 | " " | 423.5 + Key | 1 | " " | 34.3 + Plug | 1 | " " | 1,192.5 + Yoke | 1 | " " | 57.3 + Dogs | 2 | " " | 106.0 + Slot cover | 1 | Rolled steel | 6.4 + Plug cover | 1 | Cast iron | 162.0 + Dog holders | 2 | Rolled steel | 6.4 + --------------------+-----+---------------+-------------------- + Complete weight of one pair, without bolts| 7,620.4 + ==========================================+==================== + +_Sump Segments._--In order to provide sumps to collect the drainage and +leakage water in the subaqueous tunnels, special "sump segments" were +installed in each tunnel at the lowest point--about Station 241 + 00. +The details of the design are shown in Fig. 14. The segment was built +into the tunnel invert as though it were an ordinary "_A_" segment. In +building the sump, three lining castings were bolted, one on top of the +other, and attached to the flat upper surface of the sump segment; +meanwhile, the bolts attaching the sump segment to the adjacent tunnel +plates were taken out and the plate and lining segments were forced +through the soft mud by hydraulic jacks, the three 6-in. holes in the +bottom of the sump segment being opened in order to minimize the +resistance. The sump when built appeared as shown in Fig. 14, the top +connection being made with a special casting, as shown. + +The capacity of each sump is 500 gal., which is about the quantity of +water entering the whole length of each subaqueous tunnel in 24 hours. + +_Cross-Passages._--When the contract was let, provision was made for +cross-passages between the tubular tunnels, in the form of special +castings to be built into the tunnel lining at intervals. However, the +idea was given up, and these castings were not made. Later, however, +after tunnel building had started, the question was raised again, and it +was thought that such cross-connections would be very useful to the +maintenance forces, that it might be possible to build them safely, and +that their subsequent construction would be made much easier if some +provision were made for them while the shields were being driven. It was +therefore arranged to build, at intervals of about 300 ft., two +consecutive rings in each tunnel, at the same station in each tunnel, +with their longitudinal flanges together, instead of breaking joint, as +was usually done. The keys of these rings were displaced twelve bolt +holes from their normal positions toward the other tunnel. This brought +the keys about 6 ft. above the bench, so that if they were removed, +together with the _B_ plates below them, an opening of about 5 by 7 ft. +would be left in a convenient position with regard to the bench. + +[Illustration: DETAILS OF SUMPS IN SUBAQUEOUS TUNNELS AT STATION 241 +FIG. 14.] + +Nothing more was done until after the tunnels were driven. It was then +decided to limit the cross-passages between the tubular tunnels to the +landward side of the bulkhead walls. They were arranged as follows: +three on the New York side, at Stations 203 + 22, 206 + 80, and 209 + +80, and two on the New Jersey side, at Stations 255 + 46 and 260 + 14. +The cross-passages are square in cross-section. + +TABLE 21.--WEIGHTS OF SUMP SEGMENTS. + + ====================+=====+===============+==================== + Part. | No. | Material. | Weight, in pounds. + --------------------+-----+---------------+-------------------- + Middle top casting | 1 | Cast steel | 880 + End top castings | 2 | " " | 1,718 + Lining castings | 3 | " " | 18,232 + Sump segment | 1 | Cast iron | 3,560 + --------------------+-----+---------------+-------------------- + Total weight per sump, exclusive of bolts | 24,390 + ==========================================+==================== + +_Turnbuckle Reinforcement for Cast-Iron Segments._--During the period of +construction, a certain number of cast-iron segments, mostly in the +roof, but in some cases at Manhattan in the invert, behind the river +lines, became cracked owing to uneven pressures of the ground. Before +the concrete lining was put in, considerable discussion occurred as to +the wisest course to pursue with regard to these broken plates. It was +finally thought best not to take the plates out, as more harm than good +might be done, but to reinforce them with turnbuckles, as shown in Fig. +15. The number of broken segments was distributed as follows: + + North Manhattan Tunnel 87, chiefly in silt (not under the river), + South Manhattan Tunnel 7, chiefly in silt ( " " " " ), + North Weehawken Tunnel 24, chiefly in sand ( " " " " ), + South Weehawken Tunnel 48, chiefly in silt, under the Fowler + Warehouse. + +The chief features of the tunnel lining have now been described, and, +before giving any account of the methods of work, it will be well to +mention briefly the salient features of the concrete lining which is +placed within the actual lining. + + +Design of Concrete Lining. + +This concrete lining will be considered and described in the following +order: + + The New York Shield Chambers, + + Standard Cross-Section of Concrete Lining of Shield-Driven + Tunnels, + + Final Lines and Grades, and How Obtained, + + Steel Rod Reinforcement of Concrete, + + Cross-Passage Lining, + + Special Provision for Surveys and Observations. + +[Illustration: SUBAQUEOUS TUNNELS TURNBUCKLES AND RODS REINFORCING +TUNNEL SEGMENTS FIG. 15.] + +_The New York Shield Chambers._--The cross-section of the concrete +lining of these chambers is shown by Plate XXXII, referred to in the +Land Tunnel Section. They are of the twin-tunnel double-bench type. The +deep space beneath the floor is used as a sump for drainage, and +manholes for access to the cable conduits are placed in the benches. + +[Illustration: TYPES OF CONCRETE LINING OF SHIELD-DRIVEN TUNNELS. FIG. +16.] + +_Standard Cross-Section of Concrete Lining of Shield-Driven +Tunnels._--The cross-section of the concrete lining of the tube tunnel +is shown in Fig. 16. There are two main types, one extending from the +shield chambers to the first bore segment, that is, to where the tunnel +leaves solid ground and passes into silt, and the other which extends +the rest of the way. The first type has a drain in the invert, the +second has not. + +The height from the top of the rail to the soffit of the arch being less +than 16 ft. 11 in., overhead pockets for the suspension of electrical +conductors were set in the concrete arch on the vertical axis line at +10-ft. centers. These pockets are shown in Fig. 16. The benches are +utilized for the cable conduits in the usual way. Ladders are provided +on one side at 25-ft. and on the other side at 50-ft. intervals, to +give access from the track level to the top of the benches. Refuge +niches for trackmen are placed at 25-ft. intervals on the single-way +conduits side only, as there is not enough room in front of the 4-way +ducts. Manholes for giving access to the cable conduits, both power, and +telephone and telegraph, are at 400-ft. intervals. + +_Final Lines and Grades, and How Obtained._--It may be well to explain +here how the final lines and grades for the track, and therefore for the +concrete lining, were obtained and determined. It is first to be +premised that the standard cross-section of the tunnel (that is, of the +concrete and iron lining combined) is not maintained throughout the +tunnel. In other words, the metal lining is of course uniform, or +practically so, throughout; the interior surface of the concrete lining +is also uniform from end to end, but the metal lining, owing to the +difficulty of keeping the shields, and hence the tunnels built within +them, exactly on the true line and grade, is not on such lines and +grades; the concrete lining is built exactly on the pre-arranged lines +and grades, consequently, the relative positions of the concrete and +metal linings vary continually along the length of the structure, +according to whether the metal lining is higher or lower than it should +be, further to the north or to the south, or any combination of these. + +As before stated, it was strongly desired to encroach as little as +possible on the standard 2-ft. concrete arch, and after some discussion +it was decided that a thickness of 1 ft. 6 in. was the thinnest it was +advisable to allow. This made it possible to permit the metal lining of +the tunnel to be 6 in. lower, in respect to the level of the track at +any point, than the standard section shows, and also allowed the center +line of the track to have an eccentricity of 6 in. either north or south +of the center line of the tunnel. This only left to be settled the +extent to which the metal lining might be higher in respect to the track +than that shown on the standard section. + +This amount was governed by the desirability of keeping sufficient +clearance between the top of the rail and the iron lining in the invert +to admit of the attachment of pile foundations and all the accompanying +girder-track system which would necessarily be caused by the use of +piles, should it ever become apparent after operation was begun, that, +after all, it was essential to have the tunnels supported in this way. +Careful studies were made of the clearance necessary, and it was +decided that 4 ft. 9 in. was the minimum allowable depth from the top of +the rail to the outside of the iron at the bottom. This meant that the +iron lining could be 3 in. higher, with respect to the track level, than +that shown on the standard section. + +All the determining factors for fixing the best possible lines and +grades for the track within the completed metal lining were now at hand. +In March, 1908, careful surveys of plan and elevation were made of the +tunnels at intervals of 25 ft. throughout. The following operations were +then performed to fix on the best lines and grades: + +First, for Line: It has been explained that the permissible deviation of +the center line of the track on either side of the center line of the +tunnel was 6 in. Had the metal lining been invariably of the true +diameter, it would have been necessary to survey only one side of the +tunnel; this would have given a line parallel to the center line, and +might have been plotted as such; then, by setting off 6 in. on either +side of this line, there would have been obtained a pair of parallel +lines within which the center line of the track must lie. Owing to +variations in the diameter of the tunnel, however, such a method was not +permissible, and therefore the following process was used: + +When running the survey lines through the tunnel (which were the center +lines used in driving the shields), offsets were taken to the inner +edges of the flanges of the metal lining, both on the north and south +sides, at axis level at each 25-ft. interval. On the plat on which the +survey lines were laid down, and at each point surveyed, a distance was +laid off to north and south equal to the following distances: + +Offset, as measured in the tunnel to north (or south), minus 10.08 ft. + +This 10.08 ft. (or 10 ft, 1 in.) represents 10 ft. 7 in., the true +radius to inside of iron, minus 6 in., the permissible lateral deviation +of the track from the axis of the tunnel. + +The result of this process was two lines, one on either side of the +survey lines, not parallel to it or to each other, but approaching each +other when the horizontal diameter was less than the true diameter, +receding from each other when the diameter was more, and exactly 12 in. +apart when the diameter was correct. As long as the center line of the +track lay entirely within these two limiting lines, the condition that +the concrete arch should not be 6 in. less in thickness than the +standard 2 ft. was satisfied, and in order to arrive at the final line, +the longest possible tangents that would be within these limits were +adopted as the final lines; and, as the survey lines were those used in +driving the tunnel shields (that is, the lines to which it was intended +that the track should be built), the amount by which the new lines thus +obtained deviated from the survey lines was a measure of the deviation +of the finally adopted track and concrete line from the original +contract lines. + +Next, for Grades: The considerations for grade were very similar to +those for line. If the vertical diameter of the tunnel had been true at +each 25-ft. interval surveyed, it would have been correct to plot the +elevations of the crown (or invert) as a longitudinal section of the +tunnel, and to have set up over those points others 6 in. above (as the +metal lining could have been 6 in. lower than the standard section, +which is equivalent to the track being an equal amount higher), and +below these crown or invert elevations others 3 in. lower (as the metal +lining could be 3 in. higher). + +Then, by joining the points 6 in. above in one line and those 3 in. +below in another, there would have been obtained lines of limitation +between which the track grades must lie. However, as the tunnel diameter +was not uniformly correct, a modification of this method had to be made, +as in the case of the line determination, the principle, however, +remaining the same. + +The elevations were taken on the inner edges of the circumferential +flanges of the metal lining, not only in the bottom, but also in the +top, of the tunnel, at each 25-ft. interval; then, for the upper limit +of the track at each such interval the following was plotted: + +Elevation of inner edge of flange at top, minus 16.58 ft. + +This 16.58 ft. (or 16 ft. 7 in.) was obtained thus: The standard height +from the top of the rail to the inner edge of the iron flange is 17 ft. +1 in., but, as the track may be 6 in. above the standard or normal, the +minimum height permissible is 16 ft. 7 in. For the lower limit of track +at each 25-ft. interval the following was plotted: + +Elevation of inner edge of flange at bottom, plus 3.83 ft. + +This 3.83 ft. (or 3 ft. 10 in.) was obtained thus: The standard height +from the top of the rail to the inner edge of the iron flange is 4 ft. 1 +in. (5 ft. to outside of iron, less 11 in. for depth of flange), but, +as the track may be 3 in. below the standard, the minimum height +permissible is 4 ft, 1 in. less 3 in., or 3 ft. 10 in. + +By plotting the elevations thus obtained, two lines were obtained which +were not parallel but were closer together or further apart according as +the actual vertical diameter was less or greater than the standard, and +the track grade had to lie within these two lines in order to comply +with the requirements indicated above. The results of these operations +for the North Tunnel are shown on Plate XXXVI. + +The greatest deviations between the lines and grades in the subaqueous +tunnels as determined by these means and those as originally laid out in +the contract drawings are on the Weehawken side, and were caused by the +unexpected behavior of the tunnel when the shields were driven "blind" +into the silt, causing a rise which could not be overcome, and the +thrusting aside of one tunnel by the passage of the neighboring one. Had +this unfortunate incident not occurred, it is clear that it would have +been possible to adhere very closely indeed to the contract lines and +grades, although the deviation is small, considering all things. + +The internal outline of the concrete cross-section is uniform +throughout, and is built on the lines and grades thus described. + +_Steel Rod Reinforcement of Concrete._--The original intention had been +to line the metal lining of the tube tunnels with plain concrete, but, +as the discussion on the foundation question continued, it was felt +advisable, while still it was intended to put in the foundations, to +guard against any stresses which were likely to come on the structure, +by using a system of steel rods embedded circumferentially within the +concrete. Designs were made on this basis, and even the necessary +material prepared, before the decision to omit the piles altogether was +reached. However, in order to provide a safeguard for the structure +where it is partly or wholly beyond the solid rock, it was decided to +use reinforcement, even with the piles omitted. + +For this purpose the tunnel was considered as a girder, and longitudinal +reinforcement was provided at the top and bottom. The top reinforcement +extends from a point 25 ft. behind the point where the crown of the +tunnel passes out of rock on the New York side to where the crown passes +into rock on the New Jersey side. The bottom reinforcement extends from +where the invert of the tunnel passes out of rock on the New York side +to where it passes into rock on the New Jersey side. + +The reinforcement both at top and bottom consists of twenty 1-in. square +twisted rods, ten placed symmetrically on either side of the vertical +axis, 9 in. apart from center to center and set 4 in. (to their centers) +back from the face of the concrete. + +As a further precaution, circumferentially-placed rods were used on the +landward side of the river lines, mainly to assist in preventing the +distortion of shape which might occur here, either under present +conditions, such as under the Fowler Warehouse at Weehawken, or under +any possible different future conditions, such as might be brought about +by building some new structure in the vicinity of the tunnels. + +For purposes of classification of the circumferential reinforcement, the +tunnel was divided into two types, "_B_" and "_C_"; (Type "_A_" covering +the portion which, being wholly in solid rock, was not reinforced at +all). + +Type "_B_" covers the part of the tunnels on both sides of the river +lying between the point where the top of the tunnel passes out of rock +and the point where the invert passes out of rock on the Manhattan side, +or out of gravel on the Weehawken side. The reinforcement consists of +twenty 1-in. square longitudinal rods in the crown of the tunnel, as +described for the general longitudinal reinforcement, together with +1-in. square circumferential rods at 10-in. centers, and extending over +the arch to 2 ft. 3 in. below the horizontal axis. + +Type "_C_" extends from the latter limit of Type "_B_" to the river line +on each side, and consists of longitudinal reinforcement in both top and +bottom, as described before, together with circumferential reinforcement +entirely around the tunnel, and formed of 1-in. square twisted rods at +15-in. centers. + +Type "_D_" consists of longitudinal reinforcement only, and extends from +river line to river line, thus occupying 72.5% of the length in which +concrete is used. The reinforcement consists of twenty 1-in. twisted +rods at 9-in. centers in the crown, and twenty 1-in. rods at 9-in. +centers in the invert. In addition to the three standard types, "_B_," +"_C_," and "_D_," there were two sub-types which were used in Type +"_D_," and in conjunction with it wherever the thickness of the center +of the concrete arch became less than 1 ft. 6 in., measuring to the +outside of the metal lining. This thickness was one of the limits used +in laying out the lines and grades, and in general the arch was not less +than this. There were one or two short lengths, however, where it was +less, for, if the arch thickness requirement had been adhered to, it +would have resulted in a break of line or grade for the sake of perhaps +only a few feet of thin arch, and it was here that the sub-types came +into play. + +Sub-type 1 was used where the arch was less than 1 ft. 6 in. thick at +the top. The extra reinforcement here consisted of 1-in. square twisted +rods, 16 ft. long, laid circumferentially in the crown at 10-in. +centers. + +Sub-type 2 was used where the arch was less than 1 ft. 6 in. thick at +the side. The extra reinforcement here consisted of 1-in. square twisted +rods, 16 ft. long, laid circumferentially, at the side on which the +concrete was thin, at 10-in. centers. Very little of either of these two +sub-types was used. The entire scheme is shown graphically and clearly +on Plate XXXVII. + +_Cross-Passage Lining._--There are two main types of cross-passages: +Lined with steel plates, and unlined. + +There is only one example of lining with steel plates, namely, the most +western one at Weehawken. This is built in rock which carried so much +water that, in order to keep the tunnels and the passage dry, it was +decided to build a concrete-lined passage, without attempting to stop +the flow of water, and within this to place a riveted steel lining, not +in contact with the concrete, but with a space between the two. This +space was drained and the water led back to the shield chamber and +thence to the Weehawken Shaft sump. The interior of the steel lining is +covered with concrete. + +In the passages not lined with steel plates the square concrete lining +is rendered on the inside with a water-proof plaster. Each of the +passages is provided with a steel door. + +_Provisions in Concrete Lining for Surveys and Observations._--The long +protracted discussion as to the provision for foundations in these +tunnels led to many surveys, tests, and observations, which were carried +out during the constructive period, and, as it was desired to continue +as many of these observations as possible up to and after the time when +traffic started, certain provisions were made in the concrete lining +whereby these requirements might be fulfilled. The chief points on which +information was desired were as follows: + + The change in elevation of the tunnel, + The change in lateral position of the tunnel, + The change in shape of the tunnel, + The tidal oscillation of the tunnel. + +A detailed account of these observations will be found in another paper +on this work, but it may be said now that it was very desirable to be +able to get this information independently of the traffic as far as +possible, and therefore provision was made for carrying on the +observations from the side benches. + +For studying the changes in level of the tunnel, a permanent bench-mark +is established in each tunnel where it is in the solid rock and +therefore not subject to changes of elevation; throughout the tunnel, +brass studs are set in the bench at intervals of about 300 ft. A series +of levels is run every month from the stable bench-mark on each of these +brass plugs, thus obtaining an indication of the change of elevation +that the tunnels have undergone during the month. + +These results are checked on permanent bench-marks in the subaqueous +portion of the tunnels. These consist of rods, encased in pipes of +larger diameter, which extend down through the tunnel invert into the +bed-rock below the tunnel. Leakage is kept out by a stuffing-box in the +invert. By measuring between a point on these rods where they pass +through the invert and the tunnel itself a direct reading of the change +of elevation of the tunnel is obtained. These measurements are taken at +weekly intervals, and, as the tunnels are subject to tidal influences, +being lower at high tide than at low tide, are always taken under the +same conditions as to height of water in the river. These permanent +bench-marks are at Stations 209 + 05 and 256 + 02 (about 100 ft. on the +shoreward side of the river line in each case) in the South Tunnel, at +Stations 220 + 00 and 243 + 86, also in the South Tunnel, and at Station +231 + 78 in the North Tunnel. In order to study the lateral change of +position, a base line was established on the side bench at each end of +each tunnel in the portion built through the solid rock. + +At intervals of about 300 ft. throughout each tunnel, alignment pockets +are formed in the concrete arch, also above the bench, on the south +bench of the North Tunnel and the north bench of the South Tunnel. In +each pocket is placed a graduated and verniered brass bar, so that, when +the base line is projected on these bars, the lateral movement of the +tunnel can be read directly. As it was desirable to have as much +cross-connection as possible between the tunnels at the points where the +instruments were to be set up, five of the main survey stations were set +opposite each of the five cross-passages. Then, for the purpose of +increasing the cross-connection still further, pipes 6 in. in diameter +were put through from one tunnel to the other at axis level at Stations +220 + 60, 231 + 78, 234 + 64, 241 + 99, and 251 + 13, and a survey +station was put in opposite each one. + +Points were established at Station 220 + 00, which is the point of +intersection for the curve on the original center line of the tunnel, +and also at Station 220 + 23, where the intersection of the track center +line comes in the North Tunnel. As it was desirable to have the survey +stations not much more than 300 ft. apart, so as to obtain clear sights, +other stations were established so that the distances between survey +stations were at about that interval. + +For studying changes of shape in the tunnel, brass "diameter markers" +were inserted at each survey station in the concrete lining at the +extremities of the vertical and horizontal axes. These were pieces of +brass bar, 3/8 in. in diameter and 6 in. long, set in the concrete and +projecting 5/8 in. into the tunnel, so that a tape could be easily held +against the marker and read. + +For obtaining the tidal oscillation of elevation of the tunnel, +recording gauges are attached to the invert of the tunnel at each of the +five permanent bench-marks referred to above in such a way that the +recording pencil of the gauge is actuated by the rod of the permanent +bench-mark. A roll of graduated paper is driven by clock-work below the +recording pencil which thus marks automatically the relative movement +between the moving tunnel and the stable rods. These have shown that in +the subaqueous part of the tunnel there is a regular tidal fluctuation +of elevation, the tunnel moving down as the tide rises, and rising again +when the tide falls. For an average tide of about 5 ft. the tunnel +oscillation would be about 1/8 in. Before the concrete lining was +placed, there was a tidal change in the shape of the tunnel, which +flattened about 1/64 in. at high tide. After the concrete lining was +placed, this distortion seemed to cease. + +The general design and plan of the work have been described, and before +giving any account of the contractor's methods in carrying it out, Table +22, showing the chief quantities of work in the river tunnels, is +presented. + + +Methods of Construction. + +The following is an account of the methods used by the contractor in +carrying out the plans which have already been described. First, it may +be well to point out the sequence of events as they developed in this +work. These events may be divided into six periods. + + _1._--Excavation and Iron Lining: June, 1903, to + November, 1906; + + _2._--Caulking and grummeting the iron lining: + November, 1906, to June, 1907; + + _3._--Surveys, tests and observations: April, 1907, to + April, 1908; + + _4._--Building cross-passages and capping pile bores: + April, 1908, to November, 1908; + + _5._--Placing the concrete lining: November, 1908, to + June, 1909; + + _6._--Cleaning up and various small works: June, 1909, + to November, 1909. + +The tunnels were under an average air pressure of 25 lb. per sq. in. +above normal for all except Periods 5 and 6, during which times there +was no air pressure in the tunnels. + +All the work will be described in this paper except that under Period 3 +which will be found in another paper. + +_Period 1.--Excavation and Iron Lining, June, 1903, to November, +1906._--Table 23 gives the chief dates in connection with this period. + +_Manhattan Shield Chambers._--The Manhattan shield chamber construction +will be first described. The Weehawken shield chambers have been +described under the Land Tunnel Section, as they are of the regular +masonry-lined Land Tunnels type, whereas the Manhattan chambers are of +segmental iron lining with a concrete inner lining. + +During the progress of excavation, the location of the New York shield +chambers was moved back 133 ft., as previously described in the "Land +Tunnel" Section, and when the location had been finally decided, there +was a middle top heading driven all through the length now occupied by +the shield chamber. Narrow cross-drifts were taken out at right angles +to the top heading, and from the ends of these the wall-plate headings +were taken out. Heavy timbering was used, as the rock cover was only +about 6 ft., and the whole span to be covered was 60 ft. The process +adopted was to excavate and timber the north side first, place the iron +lining, and then excavate the south side, using the iron of the north +side as the supports for the north ends of the segmental timbering of +the south. The only incident of note was that at 2:00 A.M., on October +20th, 1904, the rock at the west end of the south wall-plate heading was +pierced. Water soon flooded the workings, and considerable disturbance +was caused in the New York Central Railroad yard above. The cavity on +the surface was soon filled in, but to stop the flow of mud and water +was quite a troublesome job. + +TABLE 22.--QUANTITIES OF WORK IN SUBAQUEOUS TUNNELS. + + ============================+========================================= + | TYPE. + |----------+--------------+--------------+ + DESCRIPTION, QUANTITY, |MANHATTAN | CAST IRON, | CAST IRON, | + LENGTH, ETC. |shield | ordinary | ordinary | + |chambers. | pocketless. | pocket. | + ----------------------------+----------+--------------+--------------+ + Length, in feet. | 59.00| 4,374.99 | 2,146.3 | + ----------------------------+----------+--------------+--------------+ + Excavation, in cubic yards. | | | | + Total. | 1,884 | 67,344 | 33,038 | + Per linear foot. | 31.9 | 15.4 | 15.4 | + Cast-iron tunnel lining, | | | | + in pounds. | | | | + Total. |847,042 |39,643,120 |19,715,405 | + Per linear foot. | 14,357 | 9,061 | 9,186 | + Cast-steel tunnel lining, | | | | + in pounds. | | | | + Total. | | 1,544,962 | 757,938 | + Per linear foot. | | 353.1 | 353.1 | + Steel bolts and washers, | | | | + in pounds. | | | | + Total. | 23,627 | 1,475,991 | 724,095 | + Per linear foot. | 400.46| 337.37 | 397.00 | + Rust joints, in linear feet.| | | | + Total. | 3,376 | 170,755 | 83,935 | + Per linear foot. | 57.2 | 39.0 | 39.1 | + Concrete, in cubic yards. | | | | + Total. | 766 | 20,030 | 9,827 | + Per linear foot. | 12.98| 4.58 | 4.58 | + Steel beams, plates, etc., | | | | + in pounds. | | | | + Total. | 12,346 | 83,774 | 41,098 | + Per linear foot. | 2,092.5 | 19.1 | 19.1 | + Steel bolts, hooks, etc., | | | | + in pounds. | | | | + Total. | 1,328 | 36,980 | 18,142 | + Per linear foot. | 22.5 | 84.5 | 84.5 | + Expanded metal, in pounds. | | | | + Total. | 594 | 2,215 | 1,086 | + Per linear foot. | 10.07| 0.506| 0.506| + Vitrified conduits, in | | | | + duct feet. | | | | + Total. | 2,560 | 235,903 | 115,728 | + Per linear foot. | 43.49| 53.92 | 53.92 | + ============================+==========+==============+==============+ + + ============================+========================================== + | + |--------------+-------------+------------- + DESCRIPTION, QUANTITY, | CAST IRON, | CAST STEEL, | + LENGTH, ETC. | heavy | ordinary | Total. + | pocketless. | pocketless. | + ----------------------------+--------------+-------------+------------- + Length, in feet. | 5,522.05 | 152.66 |12,255.00 ft. + ----------------------------+--------------+-------------+------------- + Excavation, in cubic yards. | | | + Total. | 85,001 | 2,349 | 189,616 + Per linear foot. | 15.4 | 15.4 | cu. yd. + Cast-iron tunnel lining, | | | + in pounds. | | | + Total. |61,559,845 | | 121,765,412 + Per linear foot. | 11,148 | | lb. + Cast-steel tunnel lining, | | | + in pounds. | | | + Total. | 2,730,905 |1,549,711 | 6,583,516 + Per linear foot. | 494.5 | 10,151.4 | lb. + Steel bolts and washers, | | | + in pounds. | | | + Total. | 2,935,455 | 51,266 | 5,210,434 + Per linear foot. | 581.59 | 335.82 | lb. + Rust joints, in linear feet.| | | + Total. | 218,656 | 5,996 | 482,718 + Per linear foot. | 39.6 | 39.3 | ft. + Concrete, in cubic yards. | | | + Total. | 25,282 | 713 | 56,618 + Per linear foot. | 4.58 | 4.58 | cu. yd. + Steel beams, plates, etc., | | | + in pounds. | | | + Total. | 105,738 | 7,432 | 250,388 + Per linear foot. | 19.1 | 48.7 | lb. + Steel bolts, hooks, etc., | | | + in pounds. | | | + Total. | 46,675 | 1,471 | 104,596 + Per linear foot. | 84.5 | 96.4 | lb. + Expanded metal, in pounds. | | | + Total. | 2,795 | 62 | 6,752 + Per linear foot. | 0.506| 0.406| lb. + Vitrified conduits, in | | | + duct feet. | | | + Total. | 297,752 | 7,757 | 659,700 + Per linear foot. | 53.92 | 50.81 | duct ft. + ============================+==============+=============+============ + +TABLE 23.--EXCAVATION AND IRON LINING. + + ====================================+================+================| + | North | North | + | Manhattan. | Weehawken. | + ------------------------------------+----------------+----------------| + Shaft and preliminary headings. | June 10, '03. | June 11, '03. | + Begun. | | | + Shaft and preliminary headings. |December 11, '03|September 1, '04| + Finished. | | | + Excavation of shield chamber. Begun.| May 24, '04. |January 16, '05.| + Excavation of shield chamber. |January 21, '05.| March 25, '05. | + Finished. | | | + Cast-iron lining of shield chambers.|February 4, '05.| None. | + Begun. | | | + Cast-iron lining of shield chambers.| March 13, '05. | None. | + Finished. | | | + Excavation of tunnels begun before |October 17, '04.|January 13, '05.| + installation of shield. | | | + Commenced building falsework for | March 6, '05. | March 23, '05. | + shield. | | | + Shield parts received at shaft. | March 11, '05. | March 20, '05. | + Erection of shield begun. | March 13, '05. | March 27, '05. | + Erection of shield (structural | March 27, '05. | April 12, '05. | + steel). Finished. | | | + Erection of shield (hydraulic | May 11, '05. | May 25, '05. | + fittings). Finished. | | | + First ring of permanent cast-iron | May 12, '05. | May 29, '05. | + lining put in. | | | + First air lock bulkhead wall. Begun.| May 29, '05. | June 15, '05. | + First air lock bulkhead wall. | June 7, '05. | June 23, '05. | + Finished. | | | + Air pressure first put in tunnel. | June 25, '05. | June 29, '05. | + Rock disappeared from invert of |December 1, '05.|October 31, '05.| + tunnel. | | | + First pair of bore segments built in|December 9, '05.|January 12, '06.| + tunnel. | | | + Rip-rap of river bulkhead wall met. |February 8, '06.| None. | + First pile met (in river bulkhead |February 18, '06|January 3, '06. | + wall at Manhattan, and Fowler | | | + warehouse foundation at Weehawken). | | | + Last pile met. | March 2, '06. |February 5, '06.| + First ring erected on river side of | March 3, '06. |February 6, '06.| + shore line. | | | + Removing hood of shield. Begun. | March 27, '06. |February 6, '06.| + Removing hood of shield. Finished. | April 1, '06. |February 8, '06.| + Second air-lock bulkhead wall. | May 12, '06. | March 19, '06. | + Begun. | | | + Second air-lock bulkhead wall. | May 21, '06. | March 24, '06. | + Finished. | | | + ------------------------------------+----------------+----------------| + Tunnel holed through with meeting | September 12, 1906. | + tunnel. | | + Last ring of permanent cast-iron | October 9, 1906. | + lining built in. | | + ====================================+================+================| + + ====================================+================+================| + | South | South | + | Manhattan. | Weehawken. | + ------------------------------------+----------------+----------------| + Shaft and preliminary headings. |June 10, '03. |June 11, '03. | + Begun. | | | + Shaft and preliminary headings. |December 11, |September 1, 04| + Finished. |'03. | | + Excavation of shield chamber. Begun.|May 24, '04. |January 16, '05.| + Excavation of shield chamber. |May 13, '05. |April 19, '05. | + Finished. | | | + Cast-iron lining of shield chambers.|May 15, '05. |None. | + Begun. | | | + Cast-iron lining of shield chambers.|June 14, '05. |None. | + Finished. | | | + Excavation of tunnels begun before |January 5, '05. |January 25, '05.| + installation of shield. | | | + Commenced building falsework for |June 19, '05. |April 17, '05. | + shield. | | | + Shield parts received at shaft. |June 22, '05. |April 24, '05. | + Erection of shield begun. |June 22, '05. |April 24, '05. | + Erection of shield (structural |June 8, '05. |May 6, '05. | + steel). Finished. | | | + Erection of shield (hydraulic |August 27, '05. |June 13, '05. | + fittings). Finished. | | | + First ring of permanent cast-iron |August 27, '05. |June 14, '05. | + lining put in. | | | + First air lock bulkhead wall. Begun.|September 18, |June 21, '05. | + |'05 | | + First air lock bulkhead wall. |September 23, |July 3, '05. | + Finished. |'05 | | + Air pressure first put in tunnel. |October 6, '05. |July 8, '05. | + Rock disappeared from invert of |February 8, '06.|September 21, 05| + tunnel. | | | + First pair of bore segments built in|February 16, |December 12, '05| + tunnel. |'06. | | + Rip-rap of river bulkhead wall met. |April 11, '06. |None. | + First pile met (in river bulkhead |April 18, '06. |December 4, '06.| + wall at Manhattan, and Fowler | | | + warehouse foundation at Weehawken). | | | + Last pile met. |May 1, '06. |January 9 '06. | + First ring erected on river side of |May 9, '06. |January 19, '06.| + shore line. | | | + Removing hood of shield. Begun. |May 9, '06. |January 19, '06.| + Removing hood of shield. Finished. |May 12, '06. |January 24, '06.| + Second air-lock bulkhead wall. |July 13, '06. |March 11, '06. | + Begun. | | | + Second air-lock bulkhead wall. |July 21, '06. |March 18, '06. | + Finished. | | | + ------------------------------------+----------------+----------------| + Tunnel holed through with meeting | October 9, 1906. | + tunnel. | | + Last ring of permanent cast-iron | November 18, 1906. | + lining built in. | | + ====================================+================+================+ + +The excavation was begun on May 24th, 1904, and finished on May 15th, +1905. The segments were placed by an erector consisting of a timber boom +supported by cross-timbers running on car wheels on longitudinal timbers +at each side of the tunnel. Motion was transmitted to the boom by two +sets of tackle, and the heavy (5,000-lb.) segments were easily handled. +The erection of the lining was started on February 4th, 1905, and +finished on June 14th, 1905. + +While the shield chambers were being excavated, bottom headings were run +along the lines of the river tunnels and continued until the lack of +rock cover prevented their being driven further. These were afterward +enlarged to the full section as far as possible. The typical working +force in the shield chambers was as follows: + + _Ten-hour Shifts._ + + _Drilling and Blasting._ + + 1 Foreman @ $3.50 + 6 Drillers " 3.00 + 6 Drillers' helpers " 2.00 + 1 Blacksmith " 3.50 + 1 Blacksmith's helper " 2.25 + 1 Powderman " 2.00 + 1 Waterboy " 2.00 + 1 Nipper " 2.00 + 1 Machinist " 3.00 + 1 Machinist's helper " 1.80 + + _Mucking._ + + 1 or 2 Foremen @ $3.00 + 16 Muckers " 2.00 + +[Illustration: PLATE XXXVIII. TRANS. AM. SOC. CIV. ENGRS. VOL. LXVII, +NO. 1155. HEWETT AND BROWN ON PENNSYLVANIA R. R. TUNNELS: NORTH RIVER +TUNNELS. FIG. 1. FIG. 2.] + +_Erection of Shields._--The tunneling shields have been described in +some detail in the section of this paper dealing with the contractor's +plant. They consist essentially of two parts, the structural steelwork +and the hydraulic fittings. The former was made by the Riter Conley +Manufacturing Company, of Pittsburg, Pa., and put up by the Terry and +Tench Company, of New York City; the hydraulic fittings were made and +put in by the Watson-Stillman Company, of New York City. + +On the New York side, the shields were built inside the iron lining of +the shield chambers, hence no falsework was needed, as the necessary +hoisting tackle could be slung from the iron lining; at Weehawken, +however, the erection was done in the bare rock excavation, so that +timber falsework had to be used. The assembly and riveting took about 2 +weeks for each shield; the riveting was done with pneumatic riveters, +using compressed air direct from the tunnel supply. + +After the structural steel had been finished, the shields, which had +hitherto been set on the floor of the chambers in order to give room for +working over the top, were jacked up to grade; this involved lifting a +weight of 113 tons. While the hydraulic fittings were being put in, the +shields were moved forward on a cradle, built of concrete with steel +rails embedded, on which the shield was driven for the length in which +the tunnel was in solid rock. + +The installation of the hydraulic fittings took from 4 to 6 weeks per +shield. The total weight of each finished shield was about 193 tons. The +completed shield, as it appeared in the tunnel, is shown by Fig. 1, +Plate XXXVIII. The typical force working on shield erection was as +follows: + + _Ten-hour Shifts._ + + _Shield Erection._ (_Terry and Tench._) + + 1 Superintendent @ $13.00 per day + 4 Foremen " 5.50 " " + 1 Timekeeper " 2.50 " " + 2 Engineers " 4.50 " " + 34 Iron workers " 4.50 " " + 7 Laborers " 2.25 " " + + _Hydraulic Work._ (_Watson-Stillman Company._) + + 4 Mechanics @ $4.00 per day + _General Labor._ (_O'Rourke Engineering Construction Company._) + + 1 Inspector @ $4.00 per day + 1 Foreman " 4.00 " " + 8 Laborers " 2.00 " " + 1 Engineer " 2.50 " " + +After the shield was finished and in position, the first two rings of +the lining were erected in the tail of the shield. These first rings +were then firmly braced to the rock and the chamber lining; then the +shield was shoved ahead by its own jacks, another ring was built, and so +on. + +The description of the actual methods of work in the shield-driven +tunnels can now be given; this will be divided generally into the +different kinds of conditions met at the working face, for example, Full +Face of Rock, Mixed Face, Full Face of Sand and Gravel, Under River +Bulkhead, and Full Face of Silt. + +The last heading is the one under which by far the longest length of +tunnel was driven, and, as not much has hitherto appeared descriptive of +the handling of a shield, through this material, considerable space will +be devoted to it. + +_Full Face of Rock._--As was described when dealing with the shield +chambers, as much as possible of the rock excavation was done before the +shields were installed. On the New York side, about 146 ft. of tunnel +was completely excavated, with 71 ft. of bottom headings beyond that, +and at Weehawken, 58 and 40 ft. of tunnel and heading beyond, +respectively. This was chiefly done to avoid handling the rock through +the narrow shield doors. Test holes were driven ahead at short intervals +to make sure that the rock cover was not being lost, but, nevertheless, +at Weehawken, on February 14th, 1905, a blast broke through the rock and +let the mud flow in, filling the tunnel for half its height for a +distance of 300 ft. from its face. + +Throughout the rock section the shield traveled on a cradle of concrete +in which were embedded either two or three steel rails. In the portion +in which the whole of the excavation had been taken out, it was only +necessary to trim off projecting corners of rock. In the portion in +which only a bottom heading had been driven, the excavation was +completed just in front of the shield, the drilling below axis level +being done from the heading itself, and above that from the front +sliding platforms of the shield. The holes were placed near together and +drilled short, and very light charges of powder were used, so as to +lessen the chance of knocking the shield about too much. In this work +the small shield doors hampered the work greatly, and it might have been +well to have provided a larger bottom opening which could have been +subdivided or partly closed when soft ground was met; on the other hand, +the quantity thus handled was small, owing to the fact that the greater +part of the rock was excavated before the shields were installed. + +The space outside the lining was grouted with a 1:1 mixture of Portland +cement and sand. Large voids were hand-packed with stone before +grouting. The details of grouting will be described later. + +A typical working gang is given herewith. Two such gangs were worked per +shield per 24 hours, 10 hours per shift. All this work was done under +normal air pressure. + + _General:_ + + ½ Tunnel superintendent @ $200.00 per month + 1 Assistant tunnel superintendent " 5.00 per day + 1 General foreman " 5.00 " " + ½ Electrician " 3.50 " " + ½ Electrician's helper " 3.00 " " + ½ Pipefitter " 3.00 " " + ½ Pipefitter's helper " 2.75 " " + + _Drilling:_ + + 1 Foreman " 5.00 " " + 3 Drillers " 4.00 " " + 3 Drillers' helpers " 3.00 " " + 1 Nipper " 2.50 " " + ½ Waterboy " 2.50 " " + ½ Powderboy " 2.75 " " + + _Mucking:_ + + 1 Foreman " 3.50 " " + 8 Muckers " 2.75 " " + + _Erecting Iron and Driving Shield:_ + + 1 Erector runner " 4.00 " " + 3 Iron workers " 3.00 " " + +The duties of such a gang were as follows: The tunnel superintendent +looked after both shifts of one shield. The assistant or "walking boss" +had charge of all work in the tunnel on one shift. The general foreman +had charge of the labor at the face. The electricians looked after +repairs, extensions of the cables, and lamp renewals. The pipefitters +worked in both tunnels repairing leaks in pipes between the power-house +and the working faces, extending the pipe lines, and attending to shield +repairs, and in the latter work the erector runner helped. + +The drillers stuck to their own jobs, which were not subject to +interruption as long as the bottom headings lasted. One waterboy and one +powderboy served two tunnels. The muckers helped the iron men put up the +rings of lining, as well as doing their own work. The iron men tightened +bolts, whenever not actually building up iron. The list does not include +the transportation gang, which will be described under its own heading. + +The rate of progress attained was 4.2 ft. per day per shield where most +of the excavation had been done before, and 2.1 ft. where none had been +done before. + +When the shields had got far enough away from the shield chamber, and +before rock cover was lost, the first air-lock bulkhead walls were put +in. + +_Air-Lock Bulkhead Walls._--The specifications required these walls and +all their fittings to be strong enough to stand a pressure of 50 lb. per +sq. in. Accordingly, all the walls were of concrete, 10 ft. in +thickness, except the first two, which were 8 ft. in thickness, and +grouted up tight. + +There were three locks in each bulkhead wall capable of holding men, +namely, the top or emergency lock which is set high in order to afford a +safe means of getting away in case of a flood; this lock was used +continuously for producing the lines and levels into the tunnels. It was +very small and cramped for this purpose, and a larger one would have +been better, both for lines and emergencies. This lock was directly +connected with the overhead platform (also called for in the +specifications) which ran the whole length of the tunnels. Side by side, +on the level of the lower or working platform of the tunnel, were the +man lock and the muck lock. In addition a number of pipes were built in +to give access to the cables and for passing pipes, rails, etc., in and +out. + +After each tunnel was about 1,200 ft. ahead of the first walls, a second +wall was built just like the first, and no others were put in, so that +altogether there were eight walls. This second wall not only gave an +added safeguard to the tunnel but enabled the air pressure at the +working face to be divided between the two walls, and this compression +or decompression in stages, separated by a spell of walking exercise, +was found to be very good for the health of those working in the air. + +_Mixed Face._--When the rock cover became so thin that it was risky to +go on without the air pressure, the air pressure was turned on, starting +with from 12 to 18 lb., which was enough to stop the water from the +gravel on top of the rock. At first, when the surface of the rock was +penetrated, the soft face was held up by horizontal boards braced from +the shield until the shield was shoved. The braces were then taken out +and, as soon as the shield had been shoved, were replaced by others. As +the amount of soft ground in the face increased, the system of timbering +was gradually changed to one of 2-in. poling boards resting on top of +the shield and supported at the face by vertical breast boards, in turn +held by 6 by 6-in. walings braced both through the upper doors to the +iron lining and from the sliding platforms of the shield. The latter +were in their forward position before the shield was shoved, the +pressure being turned off and the exhaust valves opened just before the +shove began. As the shield went ahead, the platform jacks gradually +exhausted and thus held enough pressure on the face to keep it up. Fig. +17 is a sketch of this method. In driving through mixed ground a typical +working gang was about as follows: + + _General:_ + + 1/3 Tunnel superintendent @ $300.00 per month + 1 Assistant tunnel superintendent " 5.00 per day + 1 General foreman " 5.00 " " + ½ Electrician " 3.50 " " + ½ Electrician's helper " 3.00 " " + ½ Pipefitter " 3.25 " " + ½ Pipefitter's helper " 3.00 " " + + _Drilling:_ + + 1 Foreman " 5.00 " " + 2 Drillers " 3.25 " " + 2 Drillers' helpers " 3.00 " " + + _Timbering:_ + + 2 Timbermen @ $2.50 per day + 2 Timbermen's helpers " 2.00 " " + + _Mucking:_ + + 1 Foreman " 3.50 " " + 6 Muckers " 2.75 " " + + _Erecting Iron and Driving Shield:_ + + 1 Erector runner " 3.25 " " + 3 Iron workers " 3.00 " " + +The average rate of progress was 2.6 ft. per day. + +In this case there were three such gangs, each on an 8-hour shift. + +_Full Face of Sand and Gravel._--This condition of affairs was only met +at Weehawken. Two systems of timbering were used. In the first system, +Fig. 17, the ground was excavated 2 ft. 6 in. ahead of the cutting edge, +the roof being held by longitudinal poling boards, resting on the +outside of the skin at their back end and on vertical breast boards at +the forward end. When the upper part of the face was dry, it was held by +vertical breast boards braced from the sliding platform and through the +shield doors to cross-timbers in the tunnel; the lower part, which was +always wet, was held by horizontal breast boards braced through the +lower shield pockets to cross-timbers in the tunnel. This system worked +all right as long as the ground in the top was sandy enough and had +sufficient cohesion to allow the polings to be put in, but, when the +upper part was in gravel, thus making it impossible to put in the +longitudinal polings or the vertical breasting, the second system came +in. Here the excavation was only carried 1 ft. 3 in. (half a shove) +ahead of the cutting edge, and the longitudinal polings were replaced by +transverse boards supported by pipes which were placed in the holes +provided in the shield to accommodate some telescopic poling struts +which had been designed but not made. These pipes acted as cantilevers, +and were in two parts, a 2½-in. pipe wedged tight into the holes and +smaller pipes sliding inside them. After a small section of the ground +had been excavated, a board was placed against it, one of the pipes was +drawn out under it, and wedges were driven between it and the board. +These polings were kept below the level of the hood, so that when the +shield was shoved they would come inside of it; in addition, they were +braced with vertical posts from the sliding platforms. The upper part of +the face was held by longitudinal breast boards braced from the sliding +platform by vertical "soldier" pieces. The lower part of the face was +supported by vertical sheet-piling braced to the tunnel through the +lower doors. Sometimes two rows of piling were used, but generally one, +as shown in Fig. 17. Notwithstanding the fact that the breasting was +only 1 ft. 3 in. ahead of the hood, the shield was moved its full stroke +of 2 ft. 6 in., the ground around the cutting edge of the hood being +scraped away by men working bars in the place from which the temporary +breast boards at the circumference had been removed. The back pressure +on the sliding platform jacks, when the exhaust valves were only partly +open, offered a good deal of resistance, and held the face as long as +the movement of the shield was continuous. + +[Illustration: METHOD OF TIMBERING FACE IN MIXED GROUND METHOD OF +TIMBERING FACE IN SAND METHOD OF TIMBERING FACE IN SAND AND GRAVEL FIG. +17.] + +On one occasion, when for some reason the shield was stopped with the +shove only partly done, and the exhaust valves had not been shut off, +the platforms continued to slide and allowed the face to collapse; the +shield platforms and doorways, however, caught the falling sand and +gravel and the flow choked itself. + +As soon as the rock surface was penetrated and the sand and gravel were +met, which happened almost at the same time in the two Weehawken +Tunnels, the escape of air increased enormously, and it at once became +clear that it was impossible to keep enough air in the two tunnels by +the methods then in use, even when working the three compressors, each +capable of compressing 4,400 cu. ft. of free air per min. at top speed. +When the shields just entered the sand and gravel, the face had been +held by light breasting, without any special effort to prevent the +escape of air, but when it was found impossible to supply enough air, a +large amount of straw and clay was used in front of the boards. + +This cut down the escape, but, as much air was escaping through the +joints of the iron lining, these were plastered with Portland cement. +Even then, the loss was too great, therefore one tunnel was shut down +entirely and all the air was sent to the other. This allowed a pressure +of 10 lb. to be kept up in the working tunnel, and this, though less +than the head, was enough to allow progress to be made. In order to use +one tunnel as a drain for the other, the two faces were always kept +within 150 ft. of each other by working them alternately. The timbered +face was never grouted, though this would have reduced the loss of air, +as at the same time it would have decreased the progress very much, and +any one who saw the racing engines in the power-house, and realized +that a breakdown of one of them would mean the loss of the faces, was +ready to admit that the quicker this particular period was cut short, +the better. + +Above the sand and gravel lay the silt, and, when it showed in the roof, +the escape of air was immediately reduced and the two faces could be +worked simultaneously. Almost at the same time the piles supporting the +large warehouse, known as the Fowler Building, were met. Although the +face now took much less timber, the same system of breast boards as had +been used in the gravel was kept up, but in skeleton form. They were set +2 ft. 6 in. ahead of the shield, however, instead of 1 ft. 3 in., and +the transverse roof poling boards were replaced by longitudinals resting +on the shield. The more piles in the face the less timbering was done. +The piles were cut into handy lengths with axes and chisels. + +All timbering was light compared with the weight of the ground, but, as +the shove took place as soon as the set was made, it served its purpose. +When a face was closed down the whole system was greatly reinforced by +braces from the shield, the face of which was closed by the doors. + +In driving through such a face the typical 8-hour shift gang was about +as follows: + + _General:_ + + 1/3 Tunnel superintendent @ $300.00 per month. + 1 Assistant tunnel superintendent " 5.00 per day. + 1 General foreman " 5.00 " " + ½ Pipefitter " 3.25 " " + ½ Pipefitter's helper " 2.75 " " + ½ Electrician " 3.00 " " + ½ Electrician's helper " 2.75 " " + + _Timbering:_ + + 3 Timbermen " 2.50 " " + 3 Timbermen's helpers " 2.00 " " + + _Mucking:_ + + 1 Foreman " 3.50 " " + 6 Muckers " 2.75 " " + + _Erecting Iron and Driving Shield:_ + + 1 Erector runner " 3.25 " " + 1 Foreman " 4.00 " " + 4 Iron workers " 3.00 " " + +The drillers were not kept on after the rock disappeared; a foreman was +added who divided his time between iron erection and mucking. + +The average rate of progress in sand and gravel without piles was 5.1 +ft. per day per shield. When piles and silt were met in the upper part +of the face, the speed increased to 7.0 ft. per day. + +_Passing Under River Bulkhead._--At Weehawken no trouble was found in +passing under the river wall, as the bulkhead consisted of only cribwork +supported on silt, and, though the piles obstructed the motion of the +shield, they were easily cut out, and the cribwork itself was well above +the top of the shield. + +On the New York side, however, conditions were not nearly as good. The +heavy masonry bulkhead was supported on piles and rip-rap, as shown in +Fig. 18. The line of the top of the shield was about 6 ft. above the +bottom of the rip-rap, the spaces between the stones of which were quite +open and allowed a free flow of water directly from the river. As soon, +therefore, as the cutting edge of the shield entered the rip-rap there +was a blow, the air escaping freely to the ground surface behind the +bulkhead and to the river in front of it. Clay puddle, or mud made from +the excavated silt, was used in large quantities to plug up the +interstices between the stone in the working face, the air pressure +being slightly greater than that needed to keep out the water holding it +in place. The excavation of the rip-rap was a tedious affair, for it had +to be removed one stone at a time and the spaces between the newly +exposed stones plugged with mud immediately. One man stood ready with +the mud while another loosened the stones with a bar. When the shield +had advanced its own length in the rip-rap, another point for the escape +of the air was exposed at the rear end of the shield. This loss was +closed at the leading end of the last ring with mud and cement sacks. + +[Illustration: SKETCH SHOWING RIVER TUNNELS PASSING UNDER RIVER BULKHEAD +WALL AT MANHATTAN CROSS-SECTION OF RIVER BULKHEAD WALL ON AXIS OF NORTH +TUNNEL PLAN SHOWING PILES REMOVED TO ALLOW PASSAGE OF SHIELD FIG. 18.] + +As long as the shield was stationary it was possible, by using these +methods and exercising great care and watchfulness, to prevent excessive +loss of air; but, while the shield was being shoved ahead, the +difficulties were much increased, for the movement of the shield +displaced the bags and mud as fast as they were placed, and it was only +by shoving slowly and having a large number of men looking out for leaks +and stopping them up the instant they developed that excessive loss of +air could be prevented. In erecting the iron lining, as each segment was +brought into position, it was necessary to clean off the leading +surface of the previous ring and the adjacent portion of the tail of the +shield; this was always accompanied by a slight "blow," and for some +time the air pressure in the tunnel dropped from 25 to 20 lb., that is, +from greater than the balancing pressure to less, every time a segment +was placed, and on two occasions the "blow" became so great that the +tunnel pressure was reduced considerably further, and in consequence the +water from the river rushed in and was not stopped until it had risen +about 4 ft. in the tunnel invert. On such occasions the surface of the +river was greatly disturbed, rising more than 20 ft. in the air in a +sort of geyser. A large quantity of grout (about 2,500 bbl. of cement +and a similar quantity of sand in the North Tunnel and 1,000 bbl. in the +South Tunnel) was used at this point; it was forced through the tunnel +lining immediately behind the shield, greatly reducing the loss of air +and helping to bind the rip-rap together. + +When the shield had traveled 25 ft. through the rip-rap, the piles which +support the bulkhead were met. One hundred of these which were spaced at +3-ft. centers in each direction, were cut out of the path of each shield +in a distance of 35 ft. The presence of the piles caused considerable +extra labor, as each pile had to be cut into several pieces with axes to +enable it to be removed through the shield doors, otherwise they +presented no difficulties. It was not necessary to timber the face, as +the piles supported it most effectively. + +When the river line had been passed, the "blow" still continued, and as +there was no heavy ground above the tunnel the light silt was carried +away into the water by the escaping air. At one time the cover over the +crown of the tunnel was reduced to such an extent that for a distance of +30 ft. there was less than 10 ft. of very soft silt, and in some places +none at all. Therefore, the shield was stopped and the air pressure +reduced until it was less than the balancing pressure; the blow then +ceased, and about 28,000 cement bags filled with mud were dumped into +the hole (the location made it impossible to dump them _en masse_ from a +scow). They were then weighted down with rip-rap. This sealed the blow, +and the work was continued without any further disturbance from this +source. Just before the blow reached its maximum it was found that two +of the piles which had been encountered were directly in the path of one +of the proposed screw-piles. It was therefore decided to pull these, +and this was done with two 40-ton hydraulic jacks supported by the upper +sliding platforms and acting on a horizontal timber which was connected +to the piles by tie-rods and chains. The working force here was similar +to that employed in the sand and gravel section previously described. + +_In Full Face of Silt._--A full face of silt was first met under the New +York Central Railroad freight yard on the New York side. Up to this +point the ground passed through had been either solid rock or a mixed +face of rock and gravel. In both of these the full excavation had to be +taken out before the shield could be shoved, and the soft ground had +needed timbering. When the rock, gravel, and hardpan gave place to a +full face of silt, the timber was removed, all the shield doors were +opened, and the shield was shoved into the ground without any excavation +being done by hand ahead of the diaphragm. As the shield advanced, the +silt was forced through the open doors into the tunnel. After the work +had gone on in this way for some time, taking in about 90% of the full +volume of the tunnel excavation per foot forward, the air pressure was +raised from 20 to 22 lb. The result was that the silt in the face got +harder and flowed less readily through the shield, and the amount taken +in fell to about 65% of the full volume. This manner of shoving at once +caused a disturbance on the surface and the railroad tracks above the +tunnel were raised, so that the pressure was lowered to 16 lb., then the +muck got softer and the full volume of excavation was taken in; after a +while the pressure was again raised to 20 lb. + +The forcing of the shield through the silt resulted in a rising of the +bed of the river, the amount that the bed was raised depending on the +quantity of material brought into the shield. + +If the whole volume of excavation was being brought in, the surface of +the bed was not affected; when about 50% was being taken in, the surface +was raised about 3 ft.; if the shield was being driven blind, the bed +was raised about 7 ft. + +The number of open doors was regulated so as to take in the minimum +quantity of muck consistent with causing no surface disturbance. On the +average, in the North Manhattan Tunnel, all the doors were open, but in +the South Tunnel there were generally only five or six out of the total +nine. + +In front of the bulkhead wall at Manhattan the tunnels were under Pier +No. 72. This structure was supported on wooden piles, some 80 ft. or +more in length, which came down below the tunnel invert. The piles which +lay directly in the path of the tunnels, with a few exceptions, had been +pulled. In driving the tunnels through this section, great care had to +be taken not to disturb the piles on either side of the tunnels, as they +supported a heavy trestle used in disposing of the excavation from the +open cut in the terminal yard. To avoid such disturbance, a large +portion of the total excavation had to be taken through the shields. + +The first shield which passed the river bulkhead was the south one at +Weehawken. As soon as this line was crossed the silt was found to be +much softer than behind the wall, in fact it was like a fluid in many of +its properties. The fluidity could be changed by varying the tunnel air +pressure; for example, when the air pressure was made equal to the +weight of the overlying material (water and silt), the silt was quite +stiff, and resembled a rather soft clay; but when the air pressure was +from 10 to 15 lb. per sq. in. lower, it became so liquid that it would +flow through a 1½-in. grout hole in the lining, in a thick stream, at +the rate of from 10 to 50 gal. per min. as soon as the plug was taken +out. This was the point to which the contractor had long looked forward, +as he expected to be able to close all his shield doors and drive the +rest of the way across without taking in a shovelful of muck, as had +just been done under the Hudson River, on the South Tunnel of the Hudson +and Manhattan Railroad Company's Tunnels between Morton Street, New York +City, and Hoboken, N. J. The doors were shut and the shield was shoved; +the tunnel at once began to rise rapidly, notwithstanding that the +heaviest possible downward leads that the clearance between the iron and +the shield would allow were put on. At the same time, the pressures +induced in the silt by the shield shouldering the ground aside caused +the iron lining to rise about 2 in. as soon as the shield left it, and +also distorted it, the horizontal diameter decreasing and the vertical +diameter increasing by about as much as 1¼ in. An anxious discussion +followed these phenomena, as the effects had been so utterly unexpected, +and a good many different theories were advanced as to the probable +cause. It was thought that the hood of the shield might have something +to do with the trouble. The shield was stopped, the hood removed, the +doors were shut, and the driving continued. The same trouble was found, +and it was impossible to keep to grade. Work was stopped, and the +question was thoroughly debated; finally, on January 31st, 1906, the +chief engineer directed that one of the shield doors be opened as an +experiment and 50% of the excavation taken in. + +The effect was instantaneous, the shield began to come down to grade at +once, and it soon became necessary to close the door partially and +reduce the quantity of muck taken in in order to prevent the tunnel from +getting below grade. The other troubles from distortion, etc., ceased at +the same time. + +It was soon found that a powerful aid in the guidance of the shield was +thus brought to hand, for, if high, the shield could be brought down by +increasing the quantity of muck taken in, if low, by decreasing it. From +this time forward, the quantity of muck taken in at each shove was +carefully regulated according to the position of the tunnel with regard +to grade and the nature of the ground. The quantity varied from nothing +to the full volume displaced by the tunnel, and averaged 33% of the +latter. + +To regulate the flow, the bottom middle door was fitted with two steel +angles behind which were placed 6 by 6-in. timbers. In this way the +opening could be entirely closed or one of any size left. The muck +flowed into the tunnel in a thick stream, as shown in Fig. 2, Plate +XXXV, and, by regulating the rate of shove it could be made to flow just +as fast as it could be loaded into cars. + +In driving through the silt, the typical gang per shift of 8 hours per +shield was as follows: + + _General:_ + + 1/3 Tunnel superintendent @ $300 per month + 1 Assistant tunnel superintendent " 6.00 per day + 1 General foreman " 5.00 " " + ½ Electrician " 3.50 " " + ½ Electrician's helper " 3.00 " " + 1 Foreman " 4.00 " " + 2 Pipefitters " 3.50 " " + 2 Pipefitters' helpers " 3.25 " " + + _Mucking:_ + + 1 Foreman " 4.00 " " + 6 Muckers " 3.00 " " + + _Erecting Iron and Driving Shield:_ + + 1 Foreman @ $4.00 per day + 1 Erector runner " 3.50 " " + 4 Iron workers " 3.00 " " + 3 Laborers " 3.00 " " + +Three such shifts were worked per day, and the air pressure averaged 25 +lb. per sq. in. + +The increase in the number of pipefitters was due to the greatly +increased speed, and also the steadily increasing length of completed +tunnel. The three laborers in the erection gang spent their whole time +tightening bolts. The rate of progress in the silt under the river per +ring of 2½ ft. was 3 hours 21 min., exclusive of all time when work +was actually suspended. For a considerable part of the time only two +8-hour shifts were worked, owing to a shortage of iron caused by the +change in the design of the lining, whereby the original lining was +changed to a heavier one, and, as the work was also stopped for +experiments and observations, the average of the actual total time, +including all the time during which work was suspended, was 5 hours 32 +min. per ring, or 10.8 ft. per day. + +The junction of the shields under the river was made as follows: When +the two shields of one tunnel, which had been driven from opposite sides +of the river approached within 10 ft. of each other, the shields were +stopped, a 10-in. pipe was driven between them, and a final check of +lines and levels was made through the pipe. Incidentally, also, the +first through traffic was established by passing a box of cigars through +the pipe from the Manhattan shield to that from Weehawken. One shield +was then started up with all doors closed while the doors on the +stationary shield were opened so that the muck driven ahead by the +moving shield was taken in through the other one's doors. This was +continued until the cutting edges came together. All doors in both +shields were then opened and the shield mucked out. The cutting edges +were taken off, and the shields moved together again, edge of skin to +edge of skin. The removal of the cutting edge necessitated the raising +of the pressure to 37 lb. As the sections of the cutting edges were +taken off, the space between the skin edges was poled with 3-in. stuff. +Fig. 1, Plate XXXIX, is a view of the shields of the North Tunnel after +being brought together and after parts of the interior frames had been +removed. When everything except the skins had been removed, iron lining +was built up inside the skins, the gap at the junction was filled with +concrete, and long bolts were used from ring to ring on the +circumferential joint. Finally, the rings inside the shield skins were +grouted. + +[Illustration: Plate XXXIX. TRANS. AM. SOC. CIV. ENGRS. VOL. LXVIII, No. +1155. HEWETT AND BROWN ON PENNSYLVANIA R. R. TUNNELS: NORTH RIVER +TUNNELS. FIG. 1. FIG. 2.] + +In order to make clear the nature of the work done in building these +shield-driven tunnels in silt, a short description will be attempted, +this description falling into three main divisions, namely, Shoving the +Shield, Pushing Back the Jacks, and Erecting the Iron Lining. + +_Shoving the Shield._--This part of the work is naturally very +important, as the position of the shield determines within pretty narrow +limits the position of the iron built within it, hence the shield during +its forward movement has to be guided very carefully. On this work +certain instructions were issued for the guidance of the foreman in +charge of the shield. These instructions were based on results of +"checks" of the shield and iron's position by the engineering corps of +the Company, and comprised, in the main, two requirements, namely, the +leads that were to be got, and the quantity of muck to be taken in. The +"lead" is the amount that the shield must be advanced further from the +iron, on one side or the other, or on the top or bottom, as measured +from the front face of the last ring of iron lining to the diaphragm of +the shield. These leads are not necessarily true leads from a line at +right angles to the center line, as the iron may have, and in fact +usually does have, a lead of its own which is known and allowed for when +issuing the requirements for the shove. + +The foreman, knowing what was wanted, arranged the combination of shield +jacks which would give the required leads and the amount of opening on +the shield door which would give the required amount of muck. To see how +the shield was going ahead, a man was stationed at each side at axis +level and another in the crown. Each man had a graduated rod on which +the marks were so distinct that they could be read by anyone standing on +the lower platform. These rods were held against the shield diaphragm, +and, as it advanced, its distance from the leading end of the last ring +could be seen by the man in control of the jack valves. If he found that +he was not getting the required leads, he could change the combination +of jacks in action. As the time of a shove was often less than 10 min., +the man had to be very quick in reading the rods and changing the jacks. +If it was found that extensive change in the jack arrangement was +wanted, the shove could be stopped by a man stationed at the main +hydraulic control valve; but, as any such stoppage affected the quantity +of muck taken in, it was not resorted to unless absolutely necessary. + +If the quantity of muck coming in was not as desired, a stop had to be +made to alter the size of the opening, and if, while this was being +done, the exhaust valves were not closed quite tight, the silt pressure +on the face of the shield would force it back against the iron. This +fact was sometimes taken advantage of when a full opening did not let in +the desired quantity, for the shield could be shoved, allowed to return, +and shoved again. + +The time taken to shove in silt varied greatly with the quantity of +material taken in; for shoving and mucking combined, it averaged 66 +min., with an average of 13 cu. yd. of muck disposed of, or about 5 min. +per cu. yd. of material. + +_Pushing Back the Jacks._--This was a simple matter, and merely +consisted in making the loose push-back connection to each jack as it +had to be sent back. Some of the jacks became strained and bent, and had +to be taken out and replaced. Where there was silt pressure against the +face of the shield, the hydraulic pressure had to be kept on until the +ring was erected. In such cases, only two or three jacks could be pushed +back at a time, and only after a segment had been set in position, and +the pressure taken on it, could the next jack be pushed back, and so on +around the ring. The time between the finish of the shove (hydraulic +pressure turned off) and the placing of the first segment, was occupied +in pushing back the bottom jacks and cleaning dirt off the tail of the +shield, and averaged about 14 min. + +_Erecting the Iron Lining._--As soon as the shove was over, the whole +force, when in silt, set to work at building up the iron and then +tightening the bolts so that the shield could be shoved again. A section +of the tunnel with bolting and working platform is shown on Plate XL. + +In the early part of the work, when the ground was being excavated ahead +of the shield, the whole force, with the exception of those working in +front of the shield, was engaged in erecting the iron, but, as soon as +this was done, most of the men returned to the mucking, and only the +iron workers continued to tighten up bolts. On the other sections, where +the shield was shoved into the silt without excavating ahead, as soon as +the shove was completed, the whole force was engaged in the erection of +the iron and the tightening of the bolts, until they were so tight that +the shield could be shoved again for another ring. + +The iron was brought into the tunnel on flat cars, two segments to the +car, and was lifted from the car and lowered into the invert of the +shield by a block and fall and chain sling, as shown in Fig. 2, Plate +XXXIX. The bottom three or four segments were pushed around into +position with the erector, the head simply bearing against the +longitudinal flange without being attached to the segment; the upper +segments, however, were, as shown in Fig. 2, Plate XXXVIII, and Fig. 1, +Plate XLI, attached to the erector, by using the expanding bar and the +erector head designed by Mr. Patrick Fitzgerald, the Tunnel +Superintendent. This was found to be a most convenient arrangement. + +The single erector attached to the center of the shield was able to +erect the iron as fast as it could be brought into the tunnel, and even +when the weight of the segments was increased 25% (from 2,060 to 2,580 +lb.) it always proved equal to its task, although occasionally one of +the chains in the mechanism broke and delayed the work for an hour or +so; but the sum of all the delays from this cause and from breaks and +leaks in the hydraulic line only averaged 13 min. per ring. The +operating valve which was first used was a four-spindle turning valve, +but this was replaced by a sliding valve which was found to be much more +satisfactory, both in ease of operation and freedom from failure. + +As the iron was put into place, two of the middle bolts in each +longitudinal flange and two in each circumferential one were pulled as +tight as possible, and the others put in loosely; then, as soon as the +ring was in position, as large a force as could be conveniently worked +at one time was engaged in tightening the bolts. The shape of the tunnel +depended on the thoroughness of the tightening of the bolts, and the +shield was never shoved until the bolts in all the longitudinal flanges +had been thoroughly tightened. In addition, all the bolts in the +circumferential flanges below the axis were tightened, and at least +three of the six in each segment above. After the shield had been shoved +ahead, the bolts were found to have slackened, and, where the daily +progress was four rings, or more, it was necessary to have a small gang +of men always at this work. + +In order to get at the bolts, special platforms were necessary, and +throughout the greater part of the work, a traveling platform was used. +This enabled the men to reach handily all parts of the seven leading +rings. This platform was supported and moved forward on wheels fixed on +brackets to the tunnel, and was pulled forward by connecting chains +every time the shield was shoved. In the early part of the work it was +not possible to use platforms, because, in order to maintain the correct +circular shape of the iron lining, it was necessary to put in temporary +horizontal turnbuckles at axis level. These, however, were very +convenient for supporting the planks which were used as a temporary +bolting platform for the sides of the tunnel, and a temporary platform +resting on 6 by 6-in. timbers across the tunnel enabled the bolts in the +crown of the tunnel to be reached, while the 6 by 6-in. timbers were +left in to support the emergency platform previously described (Plate +XL), which extended the entire length of the tunnel. + +The time taken to erect the iron lining became shorter and shorter as +the tunnel organization became more perfect and the force better +trained, so that, whereas, in the early part of the work, it frequently +took 6 hours to erect a ring, in the latter part, when the work was +nearing completion, it was a common occurrence to erect a ring in 30 +min. The average time in the "heavy iron" section, which included the +greater part of the work under the river, was 1 hour 4 min. for the +erection of the ring and 40 min. for tightening the bolts after that had +been completed, so that the total time spent by the whole gang on +erection and bolting averaged 1 hour 44 min. per ring, exclusive of the +time spent by the small gang which was always engaged in tightening the +bolts. The average time spent in erecting and bolting, for the whole +length of the tube tunnels, was 2 hours 15 min. per ring. + +_Tables of Progress._--Tables 24, 25, 26, and 27 have been prepared to +show the time taken in the various operations at each working face. + +[Illustration: PLATE XLI. TRANS. AM. SOC. CIV. ENGRS. VOL. LXVIII, No. +1155. HEWETT AND BROWN ON PENNSYLVANIA R. R. TUNNELS: NORTH RIVER +TUNNELS. FIG. 1.] + +[Illustration: PLATE XLI. TRANS. AM. SOC. CIV. ENGRS. VOL. LXVIII, No. +1155. HEWETT AND BROWN ON PENNSYLVANIA R. R. TUNNELS: NORTH RIVER +TUNNELS. FIG. 2.] + +In Tables 24, 25, 26, and 27, the following symbols are used: + + _A_--Including assistant superintendents, foremen, and + electricians, in driving the shield, erecting iron, mucking, + attending to the electric lights, and repairing the pipe line. + + _B_--Drillers, drillers' helpers, drill foremen, and nippers. + + _C_--All men grouting. + + _D_--Engineers and laborers wholly employed on transport between the + first lock and the face. + + _E_--In rock, one car = 0.60 cu. yd.; in sand or silt = 1.20 cu. yd. + in place. + + _F_--Time between completion of mucking and putting in first plate, + spent in shoving the jacks back. + + _G_--In ordinary iron = the whole time spent on erection and + bolting. In heavy iron = the time between putting in the first + plate and placing the key only. + + _H_--Time between placing the key and starting the next shove, spent + by the whole gang in tightening bolts. In addition to this, + there was a small gang which spent its whole time at this work. + + _I_--In Table 24 the first pair of bore segments is at ring 207-208. + " " 25 " " " " " " " " " 201-202. + " " 26 " " " " " " " " " 185-186. + " " 27 " " " " " " " " " 171-172. + + Outside diameter of tunnel = 23 ft. 0 in. + Inside " " " = 21 ft. 2 in. + Length of ring = 2 ft. 6 in. + +In the "Ordinary Iron" section the time is divided between mucking +(which included the shoving and pushing back of the jacks) and the +erection time (which included the time spent by the whole gang in +tightening bolts). In the "Heavy Iron" section these times are all +separated into "Mucking," "Pushing Back Jacks," "Erecting," and +"Bolting," and here the bolting time included only that spent on bolts +by the whole gang; in addition, there was a small gang engaged solely in +tightening bolts. The lost time is the average time lost due to the +break-down of hydraulic pipe lines, damaged jacks, and broken erector +chains. The erection time is separated for the various kinds of rings, +that is, straight ordinary rings, rings containing No. 1 bore segments, +rings containing No. 2 bore segments, and taper rings, and it will be +seen that, on the average, taper rings took 22 min. (or 24%) more time +to erect and to bolt than ordinary ones, and that rings containing No. 2 +bore segments took 14 min. (or 15%) more. + +TABLE 24.--SHIELD-DRIVEN TUNNEL WORK, MANHATTAN SHAFT, RIVER TUNNEL +NORTH. Table showing the size of the gang, the amount of excavation, and +the time per ring taken for the various operations involved in building +tunnel through the several kinds of ground encountered; also the extent +and nature of all the unavoidable delays. + + TABLE 24 PART 1 + + =+===========+=======+=============+===+=============+=====+===+==+==| + W| | | AVE. NO. | + e| | | OF MEN | + i| | DESCRIPTION | IN GANG | + g| |-------+-------------+---+-------------+--+--+---+--+--| + h| | | |Ave| | | | |A | | + t| | | |air| | |D |G |i | | + | | | | | | |r |r |r | | + o| | | |P | |S |i |o | | | + f| | | |r | |h |l |u |t |T | + | | | |e | |i |l |t |r |o | + | | | |s | |e |i |i |a |t | + i| | | |s | |l |n |n |n |a | + r| Section | | |u | |d |g |g |s |l | + o| between | Length| |r |Method of |--+--+---+--| | + n| rings |in feet|Material |e |Excavation |A |B |C |D | | + -+-----------+-------+-------------+---|-------------+--+--+---+--+--| + | 1-54 | 135.0|Rock | |[P] | | | | |14| + | 55-80 | 65.0| " |19 |[P] |24| 7|1/3| 1|32| + | 81-107 | 65.0|Soft rock |18 |[P] |22| 5| | 2|29| + O| 108-153 | 117.5|Rock |14 |[P] |17|11| | 2|30| + r| 154-194 | 102.5|Rock and |14 |[P] |23| 6| | 2|31| + d| | |earth | | | | | | | + i| 195-215 | 52.5|Silt |19 |[P]Breasting |28| | | 2|30| + n| 216-393 | 445.0| " |20 |[Q]8 doors |27| | | 4|31| + a| 394-429 | 90.0|Silt, piles, |24 |[C]Breasting |28| | | 4|32| + r| | |rip-rap | | | | | | | + y| 430-509 | 200.0|Silt |23 |[Q]1 door |24| | | 3|27| + | 510-692 | 457.5| " |23 |[Q]3 doors |26| | | 4|30| + | 55-692 |1,593.0| |20 | |25| 2| | 3|30| + | 216-692 |1,192.5| |22 | |26| | | 4|30| + -+-----------+-------+-------------+---+-------------+--+--+---+--+--| + | 693-954 | 655.0|Silt |24 |[Q]1 door |28| | | 6|34| + | 955-1,014 | 150.0| " |24 |[Q]1 " |28| | | 8|36| + |1,015-1,074| 150.0| " |24 |[Q]1 " |25| | | 8|33| + H|1,075-1,134| 150.0| " |24 |[Q]1 " |27| | | 9|36| + e|1,135-1,194| 150.0| " |25 |[Q]1 " |26| | | 8|34| + a|1,195-1,224| 75.0| " |25 |[Q]1 " |24| | | 9|33| + v|1,225-1,262| 95.0| " |25 |[Q]1 " |23| | | 9|32| + y|1,263-1,277| 37.5| " |25 |[Q]1 " |24| | |10|34| + |1,278-1,307| 75.0| " |25 |[Q]1 " |21| | |10|31| + |1,308-1,326| 47.5| " |28 |[Q]1 " |27| | |11|38| + | 955-1,326| 930.0| |24 | |26| | | 9|35| + | 693-1,326|1,585.0| |24 | |27| | | 8|35| + -+-----------+-------+-------------+---+-------------+--+--+---+--+--| + A| 216-1,326|2,777.5| |23 | |27| | | 7|34| + l| 55-1,326|3,180.0| |22 | |26| | | 6|32| + l| | | | | | | | | | | + =+===========+=======+=============+===+=============+==+==+===+==+==| + + TABLE 24 PART 2 + + =+===========+====+=====+=====+========+====+====+====+====+====| + W| | | |Av. | | TIME FOR RING | + e| | | | | | ERECTION, | + i| | | |Time | | HRS. AND MIN. | + g| |----+-----| | |----+----+----+----+----| + h| |Av. |Time |per | | | | | | | + t| |No. |Muck-| |T | O | | | | | + | |of |ing, |ring,|i | r | | | | | + o| |cu. |per | |m | d | B | B | | | + f| |yd. |cu. |shov-|e J | i | o | o | T | | + | |per |yd. |ing |a | n | r | r | a | M | + | |ring| | |f c | a | e | e | p | e | + i| | | |and |o k | r | | | e | a | + r| Section | | | |r s | y | 1 | 2 | r | n | + o| between | | |Muck-+--------+----+----+----+----+----| + n| rings |E | |ing | F | G | G | G | G | G | + -+-----------+----+-----+-----+--------+----+----+----+----+----| + | 1-54 | | | |Time for|4-00| | |4-21|4-04| + | 55-80 |41 |0-31 |21-00|jacks |6-04| | |5-30|5-57| + | 81-107 |41 |0-33 |22-30|for |4-26| | | |4-26| + O| 108-153 |41 |0-39 |26-31|light |3-10| | |3-30|3-12| + r| 154-194 |41 |0-27 |18-34|iron is |2-08| J. | J. |2-40|2-10| + d| | | | |included| | | | | | + i| 195-215 |41 |0-10 | 6-46|in |3-03|3-30|3-30| |3-09| + n| 216-393 |46 |0-05 | 3-53|shoving |2-40|2-56|3-00|3-10|2-50| + a| 394-429 |46 |0-18 |17-09|and |3-43|3-39|4-46|4-11|3-56| + r| | | | |mucking | | | | | | + y| 430-509 |11 |0-10 | 1-42| |3-14|4-12|3-59|3-46|3-34| + | 510-692 |30 |0-05 | 1-47| |2-08|2-21|2-32|2-50|2-18| + | 55-692 |30 |0-15 | 7-35|[N] |3-02| | |4-31|3-12| + | 216-692 |30 |0-07 | 3-42|[N] |2-38|2-59|3-08|1-30|2-50| + -+-----------+----+-----+-----+--------+----+----+----+----+----| + | 693- 954|11 |0-12 | 1-02|[N] |1-52|2-05|2-15|2-29|2-0 | + | 955-1,014|12 |0-04 | 0-48|0-16 |0-51|1-18|1-08|0-50|0-58| + |1,015-1,074|12 |0-03 | 0-41|0-13 |0-43|0-46|0-55|0-40|0-45| + H|1,075-1,134| 8 |0-04 | 0-34|0-12 |1-04|1-01|1-15|1-20|1-08| + e|1,135-1,194| 8 |0-04 | 0-33|0-13 |0-53|0-51|0-58|0-46|0-53| + a|1,195-1,224| 6 |0-04 | 0-24|0-12 |0-58|0-42|0-53|0-50|0-54| + v|1,225-1,262| 5 |0-05 | 0-23|0-10 |0-48|0-49|0-50|0-35|0-47| + y|1,263-1,277|10 |0-04 | 0-36|0-11 |0-47|0-50|0-52|0-48|0-52| + |1,278-1,307|17 |0-04 | 1-09|0-10 |1-03|1-01|1-06|0-00|1-04| + |1,308-1,326|22 |0-05 | 1-39|0-18 |1-25|1-48|1-50|0-50|1-31| + | 955-1,326|11 |0-04 | 0-41|0-13 |0-55|0-59|1-03|0-55|0-58| + | 693-1,326|12 |0-04 | 0-51|[N] |1-27|1-34|1-41|1-38|1-31| + -+-----------+----+-----+-----+--------+----+----+----+----+----| + A| 216-1,326|19 |0-06 | 1-59|[N] |1-55|2-08|2-16|1-35|2-03| + l| 55-1,326|21 |0-10 | 4-13|[N] | | | | |2-22| + l| | | | | | | | | | | + =+===========+====+=====+=====+========+====+====+====+====+====| + + TABLE 24 PART 3 + + =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| + W| | BOLTING TIME, WHOLE |Time| | + e| | TIME ON BOLTS AFTER | | | + i| | RING IS COMPLETE. |lost| TOTAL TIME. | + g| |----+----+----+----+----| |-----+-----+-----+-----+-----| + h| | | | | | |re- | | | | | | + t| | O | | | | |pair- | | | | | + | | r | | | | |ing | | | | | | + o| | d | B | B | | | | O | | | | | + f| | i | o | o | T | |hy- | r | | | | | + | | n | r | r | a | M |drau- d | B | B | | | + | | a | e | e | p | e |lic | i | o | o | T | | + i| | r | | | e | a | | n | r | r | a | M | + r| Section | y | 1 | 2 | r | n |pip-| a | e | e | p | e | + o| between |----+----+----+----+----|ing | r | | | e | a | + n| rings | H | H | H | H | H | | y | 1 | 2 | r | n | + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + | 1-54 | Excavation partially completed previously. | + | 55-80 |} {| |27-4 | | |26-30|26-57| + O| 81-107 |} {| |26-56| | | |26-56| + r| 108-153 |} {| |29-41| | |30-1 |29-43| + d| 154-194 |} {| |20-42| | |21-14|20-44| + i| |} {| | | | | | | + n| 195-215 |} {| | 9-49|10-16|10-16| | 9-55| + a| 216-393 |} Bolting time for {|0-09| 6-42| 6-58| 7-02| 7-12| 6-52| + r| 394-429 |} light iron is {| |23-79|23-25|24-32|23-57|23-42| + y| |} included in {| | | | | | | + | 430-509 |} erection. {|0-18| 5-14| 6-12| 5-59| 5-46| 5-34| + | 510-692 |} {|0-11| 4-06| 4-19| 4-30| 4-48| 4-16| + | 55-692 |} {|0-17|10-54| | |12-23|11-04| + | 216-692 |} {|0-25| 6-45| 7-06| 7-15| 5-37| 6-57| + -+-----------|} {|----+-----+-----+-----+-----+-----| + | 693- 954|} {|0-13| 3-7 | 3-20| 3-30| 3-44| 3-15| + | 955-1,014|0-24|0-21|0-37|0-10|0-25|0 | 2-19| 2-43| 2-49| 2-04| 2-27| + |1,015-1,074|0-31|0-30|0-52|0-23|0-34|0-02| 2-10| 2-12| 2-43| 1-59| 2-15| + H|1,075-1,134|0-28|0-35|1-40|0-52|0-44|0-03| 2-21| 2-25| 3-44| 3-01| 2-41| + e|1,135-1,194|0-32|0-20|0-24|0-18|0-26|0 | 2-11| 1-57| 2-08| 1-50| 2-05| + a|1,195-1,224|0-19|0-20|0-34|0-35|0-23|0 | 1-53| 1-38| 2-03| 2-01| 1-53| + v|1,225-1,262|0-29|0-29|0-36|0-18|0-30|0 | 1-50| 1-51| 1-59| 1-26| 1-50| + y|1,263-1,277|0-23|0-23|0-41|0-23|0-27|0 | 1-57| 2-0 | 2-20| 1-58| 2-06| + |1,278-1,307|0-33|0-34|0-51|0-0 |0-36|0 | 2-55| 2-54| 3-16| 0-0 | 2-59| + |1,308-1,326|0-49|0-42|0-58|0-25|0-48|0 | 4-11| 4-27| 4-45| 3-12| 4-16| + | 955-1,326|0-29|0-27|0-49|0-31|0-32|0 | 2-18| 2-20| 2-46| 2-20| 2-24| + | 693-1,326|[O] | | | | |0-06| 2-24| 2-31| 2-38| 2-35| 2-28| + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + A| 216-1,326|[O] | | | | |0-16| | | | | 4-18| + l| 55-1,326|[O] | | | | |0-12| | | | | 6-47| + l| | | | | | | | | | | | | + =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| + + TABLE 24 SUMMARY PART 1 + + ===+===========+=======+==============+====+============+==+==+===+==+==| + | | | AVE. NO. | + W| | | OF MEN | + e| | DESCRIPTION | IN GANG | + i| |-------+--------------+----+------------+--+--+---+--+--| + g| | | |Ave.| | | | | | | + h| | | |air | | | | | | | + t| | | | | | | | | A| | + | | | |P | | | D| G | i| | + o| | | |r | | | r| r | r| | + f| | | |e | | S| i| o | | | + | | | |s | | h| l| u | T|T | + i| | | |s | | i| l| t | r|o | + r| Section | | |u | | e| i| i | a|t | + o| between |Length | |r |Method of | l| n| n | n|a | + n| rings |in feet| Material |e |Excavation | d| g| g | s|l | + ---+-----------+-------+--------------+----+------------+--+--+---+--+--| + O {| 1-54 | 135.0|Rock |0 | [P] | | | | |14| + r {| 55-194 | 350.0|Earth and rock|16 | [P] |22| 6|1/3| 2|30| + d {| 195-393 | 497.5|Silt |20 |[P]Breasting|27| | | 4|31| + i {| 394-440 | 117.5| " |24 |[P]Breasting|28| | | 4|32| + n {| 441-692 | 630.0| " |23 |[Q]3 doors |25| | | 4|29| + a {|-----------+-------+--------------+----+------------+--+--+---+--+--| + r {| 216-692 |1,192.5| |22 | |26| | | 4|30| + y {|-----------+-------+--------------+----+------------+--+--+---+--+--| + {| 55-692 |1,595.0| |20 | |25| 2| | 3|30| + ---+-----------+-------+--------------+----+------------+--+--+---+--+--| + Hvy| 693-1,326|1,585.0|Silt |24 |[Q]1 door |27| | | 8|35| + ---+-----------+-------+--------------+----+------------+--+--+---+--+--| + All| 55-1,326|3,180.0| |22 | |26| | | 6|32| + ===+===========+=======+==============+====+============+==+==+===+==+==| + + TABLE 24 SUMMARY PART 2 + + ===+========+========+=======+=======+====+=====+===============+========| + W | | | | UNAVOIDABLE DELAYS | + e | | | AVERAGE TIME |(NOT INCLUDED IN AVERAGE| + i o| | | PER RING. | TIME PER RING). | + g f| | |-------+-------+----+-----+---------------+--------| + h |Average | Time | | | | | | | + t i| No. of |mucking,|Shoving| | | | | | + r| cubic | per | and | Erec- | | | | | + o| yards | cubic |mucking| tion |Lost| | | Time | + n|per ring| yard | [N] | [O] |time|Total| Items |hrs min| + ---+--------+--------+-------+-------+----+-----+---------------+--------| + O {| | | | 4-14 | | |First bulkhead |172 00| + r {| 41 | 0-32 | 21-44 | 4-4 | |25-48|Second bulkhead|119 00| + d {| 38 | 0-7 | 4-11 | 2-52 |0-9 | 7-12|Grouting |200 00| + i {| 41 | 0-18 | 11-54 | 4-17 |1-41|17-52|Blowout | 73 00| + n {| 17 | 0-6 | 2-04 | 2-34 |0-42| 5-20|Cradle |100 00| + a {|--------+--------+-------+-------+----+-----+---------------+--------| + r {| 30 | 0-7 | 3-42 | 2-50 |0-25| 6-57|Total |664 00| + y {|--------+--------+-------+-------+----+-----+---------------+--------| + {| 30 | 0-15 | 7-35 | 3-12 |0-17|11-04|Per ring | 0 30| + ---+--------+--------+-------+-------+----+-----+---------------+--------| + Hvy| 12 | 0-4 | 0-51 | 1-31 |0-06| 2-28| | | + ---+--------+--------+-------+-------+----+-----+---------------+--------| + All| 21 | 0-10 | 4-13 | 2-22 |0-12| 6-47| | | + ===+========+========+=======+=======+====+=====+===============+========| + +[N] Including time for jacks. + +[O] Including bolting time. + +[P] Excavating ahead of shield. + +[Q] Shoving shield into silt with ... doors open. + +TABLE 25.--SHIELD-DRIVEN TUNNEL WORK, MANHATTAN SHAFT, RIVER TUNNEL +SOUTH. Table showing the size of the gang, the amount of excavation, and +the time per ring taken for the various operations involved in building +tunnel through the several kinds of ground encountered; also the extent +and nature of all the unavoidable delays. + + TABLE 25 PART 1 + + =+===========+=======+==================+===+============+==+==+==+==+==| + W| | | AVE. NO. | + e| | | OF MEN | + i| | DESCRIPTION | IN GANG | + g| |-------+------------------+---+------------+--+--+--+--+--| + h| | | |Ave| | | | |A | | + t| | | |air| | |D |G |i | | + | | | | | | |r |r |r | | + o| | | |P | |S |i |o | | | + f| | | |r | |h |l |u |t |T | + | | | |e | |i |l |t |r |o | + | | | |s | |e |i |i |a |t | + i| | | |s | |l |n |n |n |a | + r| Section | | |u | |d |g |g |s |l | + o| between | Length| |r |Method of |--+--+--+--| | + n| rings |in feet|Material |e |Excavation |A |B |C |D | | + -+-----------+-------+------------------+---+------------+--+--+--+--+--| + | 1-68 | 170.0|Rock | 0 |[R] |20| 5| 5|2 |32| + | 69-95 | 67.5|Rock and earth |13 |[R] |22| 8| |2 |32| + O| 96-141 | 115.0|Rock |10 |[R] |21|13| |2 |36| + r|142-191 | 125.0|Rock and earth |15 |[R] |24| 7| |2 |33| + d|192-203 | 30.0|Silt |18 |[R]Breasting|23| | |3 |26| + i|204-388 | 462.5| " |18 |[S]7 doors |27| | |3 |30| + n|389-429 | 102.5|{Silt, piles and} |22 |[S]6 doors |24| | |4 |28| + a| | |{rip-rap. } | |[R]Breasting| | | | | | + r|430-504 | 187.5|Silt |21 |[S]3 doors |23| | |5 |28| + y|505-629 | 312.5| " |22 |[S]4 doors |25| | |6 |31| + |630-692 | 157.5| " |23 |[S]2 doors. |24| | |8 |32| + |204-692 |1,222.5| |21 | |25| | |5 |30| + | 69-692 |1,560.0| |17 | |23|4 | 0|3 |30| + -+-----------+-------+------------------+---+------------+--+--+--+--+--| + | 693-766 | 185.0|Silt |24 |[S]2 doors |21| | |6 |27| + | 767-806 | 100.0| " |24 |[S]2 " |22| | |7 |29| + H| 807-900 | 235.0| " |24 |[S]1½ " |23| | |8 |31| + e| 901-933 | 82.5| " |25 |[S]1 door |30| | |10|40| + a| 934-988 | 137.5| " |25 |[S]1 " |30| | |11|41| + v| 989-1,043| 137.5| " |25 |[S]1 " |28| | |11|39| + y|1,044-1,053| 25.0| " |26 |[S]1 " |25| | |9 |34| + |1,054-1,068| 37.5| " |26 |[S]1 " |26| | |9 |35| + |1,069-1,110| 105.0| " |26 |[S]1 " |30| | |11|41| + | 693-1,110|1,045.0| |25 | |25| | |8 |33| + -+-----------+-------+------------------+---+------------+--+--+--+--+--| + A| 204-1,110|2,267.5| |23 | |25| | |6 |31| + l| 69-1,110|2,605.0| |20 | |24|2 | |5 |31| + l| | | | | | | | | | | + =+===========+=======+==================+===+============+==+==+==+==+==| + + TABLE 25 PART 2 + + =+===========+====+=====+=====+========+====+====+====+====+====| + W| | | |Av. | | TIME FOR RING | + e| | | | | | ERECTION, | + i| | | |time | | HRS. AND MIN. | + g| |----+-----| | |----+----+----+----+----| + h| |Av. |Time |per | | | | | | | + t| |No. |Muck-| |T | O | | | | | + | |of |ing, |ring,|i | r | | | | | + o| |cu. |per | |m | d | B | B | | | + f| |yd. |cu. |shov-|e J | i | o | o | T | | + | |per |yd. |ing | a | n | r | r | a | M | + | |ring| | |f c | a | e | e | p | e | + i| | | |and |o k | r | | | e | a | + r| Section | | | |r s | y | 1 | 2 | r | n | + o| between |----| |Muck-+--------+----+----+----+----+----| + n| rings | E | |ing | F | G | G | G | G | G | + -+-----------+----+-----+-----+--------+----+----+----+----+----| + | 1-68 |41 |0-14 | 9-53|Time for|5-27| | |4-32|5-07| + | 69-95 |41 |0-24 |16-18|jacks |3-02| | |2-40|3-00| + O| 96-141 |70 |0-16 |18-16|for |2-08| | |2-27|2-09| + r| 142-191 |52 |0-20 |17-27|light |2-08| J | J |2-04|2-08| + d| 192-203 |36 |0-13 | 7-58|iron is |2-27|6-00|2-10|3-15|2-47| + i| 204-388 |37 |0-05 | 3-19|included|2-41|2-49|2-54|2-56|2-47| + n| 389-429 |40 |0-17 |12-42|in |3-15|2-36|5-03|3-26|3-27| + a| | | | |shoving | | | | | | + r| 430-504 |20 |0-06 | 1-51|and |2-53|3-17|3-00|2-57|2-59| + y| 505-629 |27 |0-05 | 2-20|mucking |2-23|2-40|2-45|2-28|2-30| + | 630-692 |22 |0-05 | 1-53| |1-54|2-10|2-22|2-23|2-02| + | 204-692 |30 |0-07 | 3-27| [T] |2-34|2-45|2-58|2-35|2-42| + | 69-692 |36 |0-11 | 6-40| [T] |2-47| | |3-18|2-52| + -+-----------+----+-----+-----+--------+----+----+----+----+----| + | 693-766 |22 |0-05 | 1-35| 0-25 |1-18|1-44|1-30|1-40|1-25| + | 767-806 |22 |0-05 | 1-19| 0-21 |1-00|0-56|1-37|1-21|1-08| + | 807-900 |19 |0-05 | 1-11| 0-17 |0-58|1-13|1-08|1-12|1-04| + H| 901-933 |19 |0-04 | 1-13| 0-09 |0-59|1-05|0-59| |1-00| + e| 934-988 |16 |0-04 | 0-54| 0-12 |0-49|0-44|0-56| |0-50| + a| 989-1,043|13 |0-05 | 0-52| 0-14 |0-51|0-44|0-52|1-14|0-52| + v|1,044-1,053|16 |0-07 | 0-40| 0-15 |1-04|1-15|0-50|0-55|1-02| + y|1,054-1,068| 8 |0-05 | 0-36| 0-08 |0-57|0-40|1-02| |0-56| + |1,069-1,110|14 |0-06 | 1-00| 0-15 |0-48|0-54|1-06|1-31|0-56| + | 693-1,110|18 |0-05 | 1-29| [T] |1-01|1-08|1-09|1-19|1-05| + -+-----------+----+-----+-----+--------+----+----+----+----+----| + A| 204-1,110|25 |0-06 | 2-35| [T] |2-09|2-19|2-33|2-19|2-17| + l| 69-1,110|29 |0-09 | 4-36| [T] |2-19| | |2-46|2-25| + l| | | | | | | | | | | + =+===========+====+=====+=====+========+====+====+====+====+====| + + TABLE 25 PART 3 + + =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| + W| | BOLTING TIME, WHOLE |Time| | + e| | TIME ON BOLTS AFTER | | | + i| | RING IS COMPLETE. |lost| TOTAL TIME. | + g| |----+----+----+----+----| |-----+-----+-----+-----+-----| + h| | | | | | |re- | | | | | | + t| | O | | | | |pair- | | | | | + | | r | | | | |ing | | | | | | + o| | d | B | B | | | | O | | | | | + f| | i | o | o | T | |hy- | r | | | | | + | | n | r | r | a | M |drau- d | B | B | | | + | | a | e | e | p | e |lic | i | o | o | T | | + i| | r | | | e | a | | n | r | r | a | M | + r| Section | y | 1 | 2 | r | n |pip-| a | e | e | p | e | + o| between |----+----+----+----+----|ing | r | | | e | a | + n| rings | H | H | H | H | H | | y | 1 | 2 | r | n | + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + | 1-68 |}Excavation partially {| |15-20| | |14-25|15-00| + | 69-95 |}completed previously. {| |19-20| | |18-58|19-18| + O| 96-141 |} {|0-03|20-27| | |20-46|20-28| + r| 142-191 |} {|0-12|19-47| | |19-43|19-47| + d| 192-203 |}Bolting time for light{|1-20|11-45|15-18|11-28|12-33|12-05| + i| 204-388 |}iron is included in {|0-05| 6-05| 6-13| 6-18| 6-20| 6-11| + n| 389-429 |}erection. {|0-38|16-35|15-56|18-23|16-46|16-47| + a| |} {| | | | | | | + r| 430-504 |} {|0-39| 5-23| 5-47| 5-30| 6-27| 5-29| + y| 505-629 |} {|0-23| 5-06| 5-23| 5-28| 5-11| 5-13| + | 630-692 |} {|0-08| 3-55| 4-11| 4-23| 4-24| 4-03| + | 204-692 |} {|0-18| 6-19| 6-30| 6-43| 6-20| 6-27| + | 69-692 |} {|0-15| 9-42| | |10-13| 9-47| + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + | 693-766 |0-43|1-09|0-52|0-50|0-49|0-07| 4-08| 5-00| 4-29| 4-37| 4-21| + | 767-806 |0-38|0-24|0-43|0-38|0-42|0-02| 3-20| 3-02| 4-02| 3-41| 3-32| + | 807-900 |0-39|0-34|0-56|0-31|0-40|0-06| 3-11| 3-21| 3-38| 3-17| 3-18| + H| 901-933 |0-34|0-26|1-47| |0-43|0-05| 3-00| 2-58| 4-13| | 3-10| + e| 934-988 |0-28|0-34|0-34| |0-30|0-06| 2-29| 2-30| 2-42| | 2-32| + a| 989-1,043|0-33|0-24|0-51|0-35|0-35|0-04| 2-34| 2-18| 2-53| 2-59| 2-37| + v|1,044-1,053|0-23|0-38|0-30|0-55|0-36| | 3-22| 3-48| 3-15| 3-45| 3-33| + y|1,054-1,068|0-33|0-25|0-35| |0-32| | 2-14| 1-49| 2-21| | 2-12| + |1,069-1,110|0-32|0-40|0-48|0-46|0-37|0-05| 2-40| 2-54| 3-14| 3-37| 2-53| + | 693-1,110|0-37|0-39|0-52|0-40|0-40|0-05| 3-12| 3-21| 3-35| 3-33| 3-19| + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + A| 204-1,110| [U]| | | | |0-12| 4-56| 5-06| 5-20| 5-06| 5-04| + l| 69-1,110| [U]| | | | |0-14| 7--0| | | 7-36| 7-15| + l| | | | | | | | | | | | | + =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| + + TABLE 25 SUMMARY PART 1 + + ===+===========+=======+==============+====+============+==+==+===+==+==| + | | | AVE. NO. | + W| | | OF MEN | + e| | DESCRIPTION | IN GANG | + i| |-------+--------------+----+------------+--+--+---+--+--| + g| | | |Ave.| | | | | | | + h| | | |air | | | | | | | + t| | | | | | | | | A| | + | | | |P | | | D| G | i| | + o| | | |r | | | r| r | r| | + f| | | |e | | S| i| o | | | + | | | |s | | h| l| u | T|T | + i| | | |s | | i| l| t | r|o | + r| Section | | |u | | e| i| i | a|t | + o| between |Length | |r |Method of | l| n| n | n|a | + n| rings |in feet| Material |e |Excavation | d| g| g | s|l | + ---+-----------+-------+--------------+----+------------+--+--+---+--+--| + O {| 1-68 | 170.0|Rock | 0 | [R] |20| 5| 5| 5|32| + r {| 69-191 | 307.5|Rock and earth|13 | [R] |22| 9| | 2|33| + d {| 192-388 | 492.5|Silt |18 |[R]Breasting|25| | | 3|28| + i {| | | | {|[S]7 doors | | | | | | + n {| 389-429 | 102.5|Silt piles and|22 |[R]Breasting|24| | | 4|28| + a {| | |rip-rap | {|[S]6 doors | | | | | | + r {| 430-692 | 657.5|Silt |22 |[S]3 doors |24| | | 6|30| + y {|-----------+-------+--------------+----+------------+--+--+---+--+--| + {| 204-692 |1,222.5| |21 | |25| | | 5|30| + {|-----------+-------+--------------+----+------------+--+--+---+--+--| + {| 69-692 |1,560.0| |17 | |23| 4| 0| 3|30| + ---+-----------+-------+--------------+----+------------+--+--+---+--+--| + Hvy| 693-1,110|1,045.0| |25 |[S]1 door |25| | | 8|33| + ---+-----------+-------+--------------+----+------------+--+--+---+--+--| + All| 69-1,110|2,605.0| |20 | |24| | | 5|31| + ===+===========+=======+==============+====+============+==+==+===+==+==| + + TABLE 25 SUMMARY PART 2 + + ===+========+========+=======+=====+====+=====+==================+=======| + W | | | | UNAVOIDABLE DELAYS | + e | | | AVERAGE TIME | (NOT INCLUDED IN AVERAGE | + i o| | | PER RING. | TIME PER RING). | + g f| | |-------+-----+----+-----+------------------+-------| + h |Average | Time | | | | | | | + t i| No. of |mucking,|Shoving| | | | | | + r| cubic | per | and |Erec-| | | | | + o| yards | cubic |mucking|tion |Lost| | | Time | + n|per ring| yard | [T] | [U] |time|Total|Items |hrs min| + ---+--------+--------+-------+-----+----+-----+------------------+-------| + O {| 41 | 0-14 | 9-53 | 5-07| |15-00|First bulkhead |160 00| + r {| 54 | 0-19 | 17-20 | 2-26|0-05|19-51|Second bulkhead |157 45| + d {| 37 | 0-09 | 5-39 | 2-47|0-63| 9-29|Grouting |200 00| + i {| | | | | | | | | + n {| 40 | 0-17 | 12-42 | 3-27|0-38|16-47|Blowout | 69 45| + a {| | | | | | | | | + r {| 24 | 0-05 | 1-58 | 2-29|0-22| 4-49|Waiting-heavy iron| 64 00| + y {|--------+--------+-------+-----+----+-----+------------------+-------| + {| 30 | 0-07 | 3-27 | 2-42|0-18| 6-27|Total |715 30| + {|--------+--------+-------+-----+----+-----+------------------+-------| + {| 36 | 0-11 | 6-40 | 2-52|0-15| 9-47|Per ring | 0 39| + ---+--------+--------+-------+-----+----+-----+------------------+-------| + Hvy| 18 | 0-05 | 1-29 | 1-45|0-06| 3-19| | | + ---+--------+--------+-------+-----+----+-----+------------------+-------| + All| 29 | 0-09 | 4-36 | 2-25|0-14| 7-15| | | + ===+========+========+=======+=====+====+=====+==================+=======| + +[R] Excavating ahead of shield. + +[S] Shoving shield into silt with ... doors open. + +[T] Including time for jacks. + +[U] Including bolting time. + +TABLE 26.--SHIELD-DRIVEN TUNNEL WORK, WEEHAWKEN SHAFT, RIVER TUNNEL +NORTH. Table showing the size of the gang, the amount of excavation, and +the time per ring taken for the various operations involved in building +tunnel through the several kinds of ground encountered; also the extent +and nature of all the unavoidable delays. + + TABLE 26 PART 1 + + =+===========+=======+=================+===+============+==+===+===+==+==| + W| | | AVE. NO. | + e| | | OF MEN | + i| | DESCRIPTION | IN GANG | + g| |-------+- ------------- +---+------------+--+---+---+--+--| + h| | | |Ave| | | | |A | | + t| | | |air| | |D |G |i | | + | | | | | | |r |r |r | | + o| | | |P | |S |i |o | | | + f| | | |r | |h |l |u |t |T | + | | | |e | |i |l |t |r |o | + | | | |s | |e |i |i |a |t | + i| | | |s | |l |n |n |n |l | + r| Section | | |u | |d |g |g |s |e | + o| between | Length| |r |Method of |--+---+---+--+--| + n| rings |in feet|Material |e |Excavation |A |B |C |D | | + -+-----------+-------+-----------------+---+------------+--+---+---+--+--| + | 1-24 | 60.0|Rock | 0 |[X] | 9|.04| 0 | 0|10| + | 25-55 | 77.5| " |20 |[X] |14|5 |0.5| 1|21| + | 56-72 | 42.5|Mixed sand and |10 |[X]Breasting|22|2 |.09| 2|26| + O| | |rock | | | | | | | | + r| 73-165 | 232.5|Sand and gravel |10 |[X] " |22|0 |0.1| 2|24| + d| 166-184 | 47.5|Sand and silt |20{|[X]Breasting|22|0 |.38| 3|25| + i| | |with piles | {|and cutting}| | | | | | + n| 185-253 | 172.5|Silt and piles |24{|piles }|23|0 |.71| 3|26| + a| 254-293 | 100.0|Silt |26 |[Y]8 doors |22|0 | 0 | 3|25| + r| 294-301 | 20.0| " |27 | |19|0 | 0 | 2|21| + y| 302-307 | 15.0| " |27 |[Y]8 doors |21|0 | 0 | 2|23| + | 308-342 | 87.5| " |28 | |19|0 | 0 | 2|21| + | 343-347 | 12.5| " |28 |[Y]8 doors |15|0 | 0 | 2|17| + | 348-459 | 280.0| " |28 | |20|0 | 0 | 3|28| + | 460-494 | 87.5| " |28 |[Y]8 doors |21|0 | 0 | 3|24| + | 495-513 | 47.5| " |28 | 8 " |23|0 | 0 | 4|27| + | 514-605 | 230.0| " |28 | 8 " |25|0 | 0 | 4|29| + | 606-624 | 47.5| " |28 | 8 " |24|0 | 0 | 4|28| + | 625-640 | 40.0| " |28 | 8 " |38|0 | 0 | 5|43| + | 25-640 |1,540.0| |20 | | | | | | | + | 185-640 |1,140.0| |26 | |23|0 |0.2| 3|26| + -+-----------+-------+-----------------+---+------------+--+---+---+--+--| + | 641-647 | 17.5|Silt |28 |[Y]8 doors |24|0 | 0 | 6|30| + | 648-751 | 260.0| " |28 |[Y]8 " |22|0 | 0 | 4|26| + | 752-795 | 110.0| " |28 |[Y]8 " |18|0 | 0 | 7|25| + | 796-825 | 75.0| " |28 |[Y]8 " |19|0 | 0 |10|28| + H| 826-854 | 72.5| " |28 |[Y]8 " |17|0 | 0 | 3|20| + e| 855-881 | 67.5| " |28 |[Y]8 " |23|0 | 0 | 9|32| + a| 882-982 | 252.5| " |28 |[Y]8 " |20|0 | 0 | 8|28| + v| 983-990 | 20.0| " |28 |[Y]8 " |21|0 | 0 | 7|28| + y| 991-1,049| 147.5| " |28 |[Y]8 " |23|0 | 0 | 7|30| + |1,050-1,074| 62.5| " |28 |[Y]8 " |24|0 | 0 | 9|33| + |1,075-1,110| 90.0| " |28 |[Y]8 " |25|0 | 0 |10|35| + | 641-1,110|1,175.0| |28 | |21|0 | 0 | 7|28| + -+-----------+-------+-----------------+---+------------+--+---+---+--+--| + A| 185-1,110|2,315.0| |28 | |22|0 |0.1| 5|27| + l| 25-1,110|2,715.0| |26 | |21|0.1|0.1| 3|24| + l| | | | | | | | | | | + =+===========+=======+=================+===+============+==+===+===+==+==| + + TABLE 26 PART 2 + + =+===========+====+=====+=====+========+====+====+====+====+====| + W| | | |Av. | | TIME FOR RING | + e| | | | | | ERECTION, | + i| | | |Time | | HRS. AND MIN. | + g| |----+-----| | |----+----+----+----+----| + h| |Av. |Time |per | | | | | | | + t| |No. |Muck-| |T | S | | | | | + | |of |ing, |ring,|i | t | | | | | + o| |cu. |per | |m | r | B | B | | | + f| |yd. |cu. |shov-|e J | a | o | o | T | | + | |per |yd. |ing |a | i | r | r | a | M | + | |ring| | |f c | g | e | e | p | e | + i| | | |and |o k | h | | | e | a | + r| Section | | | |r s | t | 1 | 2 | r | n | + o| between | | |Muck-+--------+----+----+----+----+----| + n| rings | E | |ing | F | G | G | G | G | G | + -+-----------+----+-----+-----+--------+----+----+----+----+----| + | 1-24 | 46 |0-06 | 4-32|Time |6-23| | | |6-23| + | 25-55 | 46 |0-51 |39-33|for |4-25| | |5-10|4-29| + O| 56-72 | 44 |0-21 |15-05|jacks |2-53| | |3-15|2-55| + O| | | | |for | | | | | | + r| 73-165 | 39 |0-11 | 6-56|light |2-27| | |2-21|2-26| + d| 166-184 | 42 |0-09 | 6-19|iron is |2-31| J | J |6-30|2-37| + i| | | | |included| | | | | | + n| 185-253 | 43 |0-09 | 6-13|in |1-57|2-44|2-52|2-00|2-15| + a| 254-293 | 6 |0-18 | 1-45|shoving |1-58|1-57|2-15|2-45|2-02| + r| 294-301 | 0 | | 1-08|and |0-58|1-45|1-50| |1-17| + y| 302-307 | 26 |0-09 | 4-03|mucking.|2-20|1-40|1-55|2-57|2-22| + | 308-342 | 0 | | 0-36| |2-00|1-34|2-42|1-58|2-02| + | 343-347 | 2 |0-36 | 1-11| |2-15|2-20| |2-43|2-33| + | 348-459 | 0 | | 0-33| |2-03|2-04|2-09|2-23|2-06| + | | | | | | | | | | | + | 460-494 | 9 |0-09 | 1-23| |2-49|2-30|2-50|1-50|2-38| + | 495-513 | 17 |0-05 | 1-28| |2-35|2-23|1-55|2-10|2-26| + | 514-605 | 26 |0-04 | 1-44| |2-12|2-34|2-29|2-15|2-19| + | 606-624 | 16 |0-04 | 1-07| |1-54|2-33|2-16|1-35|2-04| + | 625-640 | 24 |0-03 | 1-13| |2-14|2-55|2-35|2-46|2-28| + | 25-640 | | | | | | | | | | + | 185-640 | 16 |0-07 |1-58 | |2-07|2-19|2-26|2-15|2-13| + -+-----------+----+-----+-----+--------+----+----+----+----+----| + | 641-647 | 19 |0-04 | 0-08| [V] |1-20|2-08|1-65|1-40|1-41| + | 648-751 | 14 |0-03 | 0-36| 0-12 |1-21|1-22|1-26|1-55|1-23| + | 752-795 | 10 |0-03 | 0-29| 0-14 |0-46|1-25|1-31|2-37|1-10| + | 796-825 | 5 |0-08 | 0-40| 0-11 |0-48|1-31|1-34|0-53|1-03| + H| 826-854 | 15 |0-03 | 0-48| 0-19 |0-54|1-12|1-02|1-23|1-01| + e| 855-881 | 7 |0-05 | 0-33| 0-16 |0-59|0-45|1-15|1-20|1-01| + a| 882-982 | 10 |0-02 | 0-20| 0-14 |0-49|1-02|1-01|0-50|0-54| + v| 983-990 | 17 |0-02 | 0-34| 0-14 |0-40|0-40|0-48| |0-44| + y| 991-1,049| 8 |0-03 | 0-21| 0-11 |0-40|0-48|0-39| |0-41| + |1,050-1,074| 7 |0-03 | 0-18| 0-10 |0-43|0-44|0-46|0-40|0-43| + |1,075-1,110| 16 |0-02 | 0-33| 0-12 |0-50|1-02|1-06|0-58|0-55| + | 641-1,110| 8 |0-04 | 0-30| 0-14 |0-56|1-08|1-12|1-29|1-02| + -+-----------+----+-----+-----+--------+----+----+----+----+----| + A| 185-1,110| 12 |0-07 | 1-20| 0[V] |1-48|2-01|2-11|2-17|1-56| + l| 25-1,110|17.1|0-12 | 3-13| [V] | | | | |2-05| + l| | | | | | | | | | | + =+===========+====+=====+=====+========+====+====+====+====+====| + + TABLE 26 PART 3 + + =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| + W| | BOLTING TIME, WHOLE |Time| | + e| | TIME ON BOLTS AFTER | | | + i| | RING IS COMPLETE. |lost| TOTAL TIME. | + g| |----+----+----+----+----| |-----+-----+-----+-----+-----| + h| | | | | | |re- | | | | | | + t| | S | | | | |pair- | | | | | + | | t | | | | |ing | | | | | | + o| | r | B | B | | | | S | | | | | + f| | a | o | o | T | |hy- | t | | | | | + | | i | r | r | a | M |drau- r | B | B | | | + | | g | e | e | p | e |lic | a | o | o | T | | + i| | h | | | e | a | | i | r | r | a | M | + r| Section | t | 1 | 2 | r | n |pip-| g | e | e | p | e | + o| between |----+----+----+----+----|ing | h | | | e | a | + n| rings | H | H | H | H | H | | t | 1 | 2 | r | n | + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + | 1-24 | Excavation partially | |10-55| | | |10-55| + | 25-55 |} completed previously.{| |43-58| | |44-43|44-02| + | 56-72 |} {|0-04|18-02| | |18-24|18-04| + O| 73-165 |} {|0-09| 9-32| | | 9-26| 9-31| + r| 166-184 |} {|0-07| 8-57| | |12-56| 9-03| + d| 185-253 |} {|0-15| 8-25| 9-12| 9-20| 8-28| 8-43| + i| |} {| | | | | | | + n| 254-293 |} Bolting time for {|0-14| 3-57| 3-56| 4-14| 4-44| 4-01| + a| 294-301 |} light iron is {| | 2-06| 2-53| 2-58| | 2-25| + r| 302-307 |} included in {| | 6-23| 5-43| 5-58| 7-00| 6-25| + y| 308-342 |} erection. {| | 2-36| 2-10| 3-18| 2-29| 2-38| + | 343-347 |} {|0-39| 4-05| 4-10| | 4-43| 4-23| + | 348-459 |} {|0-14| 2-50| 2-51| 2-56| 3-10| 2-53| + | |} {| | | | | | | + | 460-494 |} {|0-27| 4-39| 4-20| 4-40| 3-40| 4-28| + | 495-513 |} {| | 4-03| 3-51| 3-23| 3-38| 3-54| + | 514-605 |} {| | 3-56| 4-18| 4-13| 3-59| 4-03| + | 606-624 |} {| | 3-01| 3-40| 3-23| 2-42| 3-11| + | 625-640 |} {| | 3-27| 4-08| 3-48| 3-59| 3-41| + | 25-640 |} {| | | | | | | + | 185-640 |} {|0-09| 4-14| 4-26| 4-33| 4-22| 4-20| + -+-----------+------------------------+----+-----+-----+-----+-----+-----| + | 641-647 |0-40|0-35|1-25|0-55|0-47| | 3-08| 3-51| 4-28| 3-43| 3-36| + | 648-751 |0-31|0-29|0-38|0-30|0-32|0-12| 2-52| 2-51| 3-04| 3-25| 2-55| + | 752-795 |0-48|0-31|0-44|0-35|0-43|0-05| 2-22| 2-44| 3-03| 4-00| 2-41| + H| 796-825 |0-31|1-03|0-49|3-27|0-51| | 2-10| 3-25| 3-14| 5-11| 2-45| + e| 826-854 |0-22|0-37|0-38|0-20|0-27|0-06| 2-29| 3-02| 2-53| 2-56| 2-41| + a| 855-881 |0-22|0-21|0-45|0-40|0-26|0-45| 2-55| 2-40| 3-34| 3-34| 3-01| + v| 882-982 |0-41|0-36|0-36|0-15|0-39|0-12| 2-16| 2-24| 2-23| 1-51| 2-19| + y| 983-990 |1-15|0-15|0-28| |0-48| | 2-43| 1-43| 2-04| | 2-20| + | 990-1,046|0-41|0-34|0-55| |0-41| | 1-53| 1-54| 2-06| | 1-54| + |1,047-1,074|0-35|1-15|0-07|0-35|0-48|0-04| 1-50| 2-31| 2-25| 1-47| 2-03| + |1,075-1,110|0-35|0-46|0-58|2-10|0-41|0-21| 2-31| 2-54| 2-10| 4-14| 2-42| + | 641-1,110|0-36|0-36|0-44|0-54|6-38|0-11| 2-27| 2-27| 2-51| 3-18| 2-35| + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + A| 185-1,110|[W] | | | | |0-10| 3-18| 3-31| 3-41| 3-47| 3-26| + l| 25-1,110|[W] | | | | |0-09| | | | | 5-27| + l| | | | | | | | | | | | | + =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| + + TABLE 26 SUMMARY PART 1 + + ===+===========+=======+==============+====+============+==+===+===+==+==| + | | | AVE. NO. | + W| | | OF MEN | + e| | DESCRIPTION | IN GANG | + i| |-------+--------------+----+------------+--+---+---+--+--| + g| | | |Ave.| | | | | | | + h| | | |air | | | | | | | + t| | | | | | | | | A| | + | | | |P | | | D | G | i| | + o| | | |r | | | r | r | r| | + f| | | |e | | S| i | o | | | + | | | |s | | h| l | u | t|T | + i| | | |s | | i| l | t | r|o | + r| Section | | |u | | e| i | i | a|t | + o| between |Length | |r |Method of | l| n | n | n|a | + n| rings |in feet| Material |e |Excavation | d| g | g | s|l | + ---+-----------+-------+--------------+----+------------+--+---+---+--+--| + O {| 1-24 | 60.0|Rock | 0 | [X] | 9|.04| 0 | 0|10| + r {| 25-55 | 77.5| " |20 | [X] |14|5 |0.5| 1|21| + d {| 56-72 | 42.5|Mixed sand and|10 |[X]Breasting|22|2 |.09| 2|26| + i {| | |rock | | | | | | | | + n {| 73-165 | 232.5|Sand & gravel |10 |[X]Breasting|22|0 |.1 | 2|24| + a {| 166-184 | 47.5|Sand and silt |20 {|[X]Breasting|22|0 |.38| 3|25| + r {| | |with piles | {|and cutting | | | | | | + y {| 185-253 | 172.5|Silt w/ piles |24 {|piles |23|0 |.71| 3|26| + {| 254-640 | 110.0|Silt |26 |[Y]Doors |22|0 | 0 | 3|25| + {|-----------+-------+--------------+----+------------+--+---+---+--+--| + {| 25-640 |1,540.0| |20 |[Y]Doors |21|0.3|.12| 3|24| + ---+-----------+-------+--------------+----+------------+--+---+---+--+--| + Hvy| 641-1,110|1,175.0| |28 | |21| 0 | 0 | 7|28| + ---+-----------+-------+--------------+----+------------+--+---+---+--+--| + All| 25-1,110|2,715.0| |26 | |21|0.1|0.1| 3|24| + ===+===========+=======+==============+====+============+==+===+===+==+==| + + TABLE 26 SUMMARY PART 2 + + ===+========+========+=======+=======+====+=====+===============+========| + W | | | | UNAVOIDABLE DELAYS | + e | | | AVERAGE TIME |(NOT INCLUDED IN AVERAGE| + i o| | | PER RING. | TIME PER RING). | + g f| | |-------+-------+----+-----+---------------+--------| + h |Average | Time | | | | | | | + t i| No. of |mucking,|Shoving| | | | | | + r| cubic | per | and | Erec- | | | | | + o| yards | cubic |mucking| tion |Lost| | | Time | + n|per ring| yard | [V] | [W] |time|Total| Items |hrs min| + ---+--------+--------+-------+-------+----+-----+---------------+--------| + O {| 46 | 0-06 | 4-32 |6-23 |0-00|10-55|First bulkhead |132-00 | + r {| 46 | 0-51 |39-33 |4-29 |0-00|44-02|Second bulkhead|158-50 | + d {| 44 | 0-21 |15-05 |2-55 |0-04|18-04|Grouting |240-00 | + i {| | | | | | |Old cave-in |234-00 | + n {| 39 | 0-11 | 6-56 |2-26 |0-09| 9-31|shoving tube |128-00 | + a {| 42 | 0-09 | 6-19 |2-37 |0-07| 9-03|---------------+--------| + r {| | | | | | | Total |892-50 | + y {| 43 | 0-09 | 6-13 |2-15 |0-05| 8-43|---------------+--------| + {| 11 | 0-07 | 1-13 |2-20 |0-08| 3-41| per ring | 0-49 | + {|--------+--------+-------+-------+----+-----+---------------+--------| + {| 24 | 0-14 | 5-06 |2-24 |0-08| 7-38| | | + ---+--------+--------+-------+-------+----+-----+---------------+--------| + Hvy| 8 | 0-04 | 0-44 |1-40 |0-11| 2-35| | | + ---+--------+--------+-------+-------+----+-----+---------------+--------| + All| 17.1 | 0-12 | 3-13 |3-05 |0-09| 5-27| | | + ===+========+========+=======+=======+====+=====+===============+========| + +[V] Including time for jacks. + +[W] Including bolting time. + +[X] Excavating ahead of shield. + +[Y] Shoving shield into silt with ... doors open. + +TABLE 27.--SHIELD-DRIVEN TUNNEL WORK, WEEHAWKEN SHAFT, RIVER TUNNEL +SOUTH. Table showing the size of the gang, the amount of excavation, and +the time per ring taken for the various operations involved in building +tunnel through the several kinds of ground encountered; also the extent +and nature of all the unavoidable delays. + + TABLE 27 PART 1 + + =+===========+=======+============+====+============+==+==+===+===+==| + W| | | AVE. NO. | + e| | | OF MEN | + i| | DESCRIPTION | IN GANG | + g| |-------+------------+----+------------+--+--+---+---+--| + h| | | |Ave | | | | |A | | + t| | | |air | | |D |G |i | | + | | | | | | |r |r |r | | + o| | | |P | |S |i |o | | | + f| | | |r | |h |l |u |t |T | + | | | |e | |i |l |t |r |o | + | | | |s | |e |i |i |a |t | + i| | | |s | |l |n |n |n |a | + r| Section | | |u | |d |g |g |s |l | + o| between | Length| |r |Method of |--+--+---+---| | + n| rings |in feet|Material |e |Excavation |A |B |C |D | | + -+-----------+-------+------------+----+------------+--+--+---+---+--| + | 1-27 | 67.5|Rock | 9 |[C] {|Excavation }| + | | | | | {|partially }| + | | | | | {|completed }| + | | | | | {|previously. }| + | 28-42 | 37.5| " |12 |[C] |13| 4|1 |1 |19| + | 43-58 | 40.0|Rock or |12 |[C] |19| 2|2 |2 |25| + | | | | | | | | + O| 59-153 | 237.5|Gravel and |16 |[C]Breasting|25| |1 |4 |30| + r| | |sand | | | | | | | | + d| 154-170 | 42.5|Sand and |18 | " |26| |1 |5 |32| + i| | |silt w/piles| | | | | | | | + n| 171-236 | 165.0|Silt with |22 |Top half |22| |1 |3 |26| + a| | |piles | | + r| 237-259 | 57.5|Silt |25 |[D]1 door |18| |1 |3 |22| + y| 260-302 | 107.5| " |27 |[D]1 door |15| | |2 |17| + | 303-350 | 120.0| " |27 |[D]8 doors |15| | |4 |19| + | 351-378 | 70.0| " |27.5|[D]8 " |18| | |6 |24| + | 379-424 | 115.0| " |27.5|[D]8 " |19| | |4 |23| + | 425-522 | 245.0| " |28 |[D]1 door |19| | |4 |23| + | 523-625 | 257.5| " |28 |[D]1 " |20| | |4 |24| + | 171-625 |1,137.5| |27 | |19| | |4 |23| + | 28-625 |1,495.0| |25 | |19|.8|0.8|3.4|24| + -+-----------+-------+------------+----+------------+--+--+---+---+--| + | 626-649 | 57.5|Silt |28 |[D]1 door |16| | | 3 |19| + | 650-733 | 210.0| " |28 |[D]8 doors |19| | | 4 |23| + | 734-753 | 50.0| " |28 |[D]8 " |24| | | 5 |29| + H| 754-844 | 227.5| " |28 |[D]8 " |26| | | 8 |34| + e| 845-859 | 37.5| " |28 |[D]8 " |27| | | 9 |36| + a| 860-899 | 100.0| " |28 |[D]8 " |24| | | 8 |33| + v| 900-935 | 90.0| " |28 |[D]1 door |25| | | 7 |32| + y| 936-963 | 70.5| " |28 |[D]1 " |25| | | 8 |33| + | 964-1,003| 100.0| " |28 |[D]1 " |25| | |10 |35| + |1,004-1,060| 142.5| " |28 |[D]1 " |26| | |10 |36| + |1,061-1,110| 125.0| " |28 |[D]1 " |37| | |10 |47| + |1,111-1,238| 320.0| " |28 |[D]1 " |30| | | 9 |39| + |1,239-1,312| 185.0| " |28 | |39| | | 9 |38| + | 626-1,312|1,717.5| " |28 | |35| | | 8 |33| + -+-----------+-------+------------+----+------------+--+--+---+---+--| + A| 171-1,312|2,855.0| |28 | |23| | | 6 |29| + l| 28-1,312|3,212.5| |26 | |21| | | 5 |26| + l| | | | | | | | | | | + =+===========+=======+============+====+============+==+==+===+===+==| + + TABLE 27 PART 2 + + =+===========+====+=====+=====+========+====+====+====+====+====| + W| | | |Av. | | TIME FOR RING | + e| | | | | | ERECTION, | + i| | | |Time | | HRS. AND MIN. | + g| |----+-----| | |----+----+----+----+----| + h| |Av. |Time |per | | | | | | | + t| |No. |Muck-| |T | O | | | | | + | |of |ing, |ring,|i | r | | | | | + o| |cu. |per | |m | d | B | B | | | + f| |yd. |cu. |shov-|e J | i | o | o | T | | + | |per |yd. |ing |a | n | r | r | a | M | + | |ring| | |f c | a | e | e | p | e | + i| | | |and |o k | r | | | e | a | + r| Section | | | |r s | y | 1 | 2 | r | n | + o| between | | |Muck-+--------+----+----+----+----+----| + n| rings | E | |ing | F | G | G | G | G | G | + -+-----------+----+-----+-----+--------+----+----+----+----+----| + | 1-27 |Excavation| | |8-30| | |3-45|8-08| + | | partially| | | | | | | | + | | completed| | | | | | | | + | |previously| | | | | | | | + | 28-42 |48.7|0-25 |20-33| |4-23| | |4-00|4-21| + | 43-58 |44.2|0-46 |33-44| |4-16| | |5-45|4-44| + | | | | | | | | | | | + O| 59-153 |39.0|0-12 | 8-06| |2-19| | |4-18|2-23| + r| | | | | | | | | | | + d| 154-170 |41.6|0-10 | 7-10| |2-00| J. | J. |1-48|1-59| + i| | | | | | | | | | | + n| 171-236 |42.6|0-10 | 7-23| |2-36|2-55|2-58|1-24|2-35| + a| | | | | | | | | | | + r| 237-259 |13.8|0-11 | 2-29| |3-01|2-05|1-28|2-00|2-32| + y| 260-302 | 0 | | 0-32| |2-34|2-35|3-38|4-28|3-05| + | 303-350 | 6.9|0-07 | 0-52| |2-59|2-28|2-37|1-44|2-41| + | 351-378 | 0 | | 0-33| |2-05|2-32|2-48|2-00|2-18| + | 379-424 | 6.9|0-07 | 0-48| |3-34|2-51|3-18|3-19|3-22| + | 425-522 | 6.7|0-06 | 0-45| |3-09|3-51|3-00|3-28|3-16| + | 523-625 | 0 | | 0-32| |1-36|1-37|1-47|1-51|1-39| + | 171-625 | 9.7|0-11 | 1-44| [A] |2-37|2-41|2-41|2-32|2-38| + | 28-625 |17.8|0-14 | 4-14| [A] | | | | |2-41| + -+-----------+----+-----+-----+--------+----+----+----+----+----| + | 626-649 |12.2|0-12 | 2-23| [A] |2-19|2-30|2-05|1-42|2-16| + | 650-733 |13.5| | 0-57| 0-13 |1-42|1-24|1-47|1-48|1-39| + | 734-753 | 8.3|0-05 | 0-41| 0-17 |1-06|1-55|0-38|1-20|1-12| + H| 754-844 |12.8|0-04 | 0-51| 0-16 |1-19|1-41|1-52|0-50|1-29| + e| 845-859 | 5.6|0-07 | 0-39| 0-19 |1-24|1-08|1-10| |1-20| + a| 860-899 |16.5|0-02 | 0-39| 0-13 |1-00|1-05|1-13| |1-04| + v| 900-935 |11.5|0-03 | 0-29| 0-14 |0-47|1-13|0-52|1-10|0-52| + y| 936-963 | 5.9|0-03 | 0-19| 0-15 |0-59|0-47|0-55| |0-56| + | 964-1,003| 8.1|0-03 | 0-27| 0-10 |0-51|0-52|1-05| |0-53| + |1,004-1,060| 8.7|0-03 | 0-30| 0-15 |1-01|1-09|1-05|0-45|1-03| + |1,061-1,110| 6.2|0-03 | 0-19| 0-10 |0-42|0-49|0-54|0-45|0-45| + |1,111-1,238|15.6|0-02 | 0-38| 0-16 |0-48|1-06|1-04|1-23|0-56| + |1,239-1,312|13.0|0-03 | 0-36| 0-18 |1-04|1-01|1-02|1-15|1-07| + | 626-1,312|10.6|0-04 | 0-42| 0-14 |1-06|1-15|1-16|1-18|1-10| + -+-----------+----+-----+-----+--------+--- |----+----+----+----| + A| 171-1,312|10.2|0-07 |1-15 | [A] |2-09|2-13|2-21|2-20|2-13| + l| 28-1,312|14.1|0-10 |2-28 | [A] | | | | |2-18| + l| | | | | | | | | | | + =+===========+====+=====+=====+========+====+====+====+====+====| + + TABLE 27 PART 3 + + =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| + W| | BOLTING TIME, WHOLE |Time| | + e| | TIME ON BOLTS AFTER | | | + i| | RING IS COMPLETE. |lost| TOTAL TIME. | + g| |----+----+----+----+----| |-----+-----+-----+-----+-----| + h| | | | | | |re- | | | | | | + t| | S | | | | |pair- | | | | | + | | t | | | | |ing | | | | | | + o| | r | B | B | | | | s | | | | | + f| | a | o | o | T | |hy- | t | | | | | + | | i | r | r | a | M |drau- r | B | B | | | + | | g | e | e | p | e |lic | a | o | o | T | | + i| | h | | | e | a | | i | r | r | a | M | + r| Section | t | 1 | 2 | r | n |pip-| g | e | e | p | e | + o| between |----+----+----+----+----|ing | h | | | e | a | + n| rings | H | H | H | H | H | | t | 1 | 2 | r | n | + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + | 1-27 |} {|0-14|21-11| | |16-26|20-49| + | |} {| | | | | | | + | |} {| | | | | | | + | |} {| | | | | | | + | 28-42 |} {|0-12|25-08| | |24-45|25-06| + | 43-58 |} {|1-15|39-15| | |40-44|39-43| + | |} {| | | | | | | + O| 59-153 |} {|0-30|10-55| | |12-54|10-59| + r| |{ {| | | | | | | + d| 154-170 |} {|0-00| 9-10| J. | J. | 8-58| 9-09| + i| |} {| | | | | | + n| 171-236 |} Bolting time for {|0-05|10-04|10-23|10-26| 8-52|10-03| + a| |} light iron is {| | | | | | | + r| 237-259 |} included in {|0-20| 5-50| 4-54| 4-17| 4-49| 5-21| + y| 260-302 |} erection. {|0-08| 3-14| 3-15| 4-18| 5-08| 3-45| + | 303-350 |} {|0-07| 3-58| 3-27| 3-36| 2-43| 3-40| + | 351-378 |} {|0-17| 2-55| 3-22| 3-38| 2-50| 3-08| + | 379-424 |} {|0-25| 4-47| 4-09| 4-31| 4-32| 4-35| + | 425-522 |} {|0-16| 4-10| 4-52| 4-01| 4-29| 4-17| + | 523-625 |} {|0-12| 2-20| 2-21| 2-31| 2-35| 2-23| + | 171-625 |} {|0-13| 4-34| 4-38| 4-38| 4-29| 4-35| + | 28-625 |} {|0-16| | | | | 7-11| + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + | 626-649 |1-01|1-04|1-04|0-50|1-01|0-32| 6-15| 6-29| 6-04| 5-27| 6-12| + | 650-733 |1-15|0-52|0-55|0-42|1-07|0-32| 4-39| 3-58| 4-24| 4-12| 4-28| + | 734-753 |0-38|0-44|1-13|0-20|0-44|0-06| 2-48| 3-43| 2-55| 2-44| 3-00| + H| 754-844 |0-39|0-50|0-54|0-40|0-44|0-25| 3-30| 4-08| 4-18| 3-02| 3-45| + e| 845-859 |0-45|0-15|0-15| |0-37|0-48| 3-55| 3-09| 3-11| | 3-43| + a| 860-899 |0-59|0-32|0-49| |0-52|0-07| 2-58| 2-36| 3-01| | 2-55| + v| 900-935 |0-39|0-43|0-32|0-20|0-38|0-04| 2-18| 2-43| 2-11| 2-17| 2-17| + y| 936-963 |0-34|0-16|0-41| |0-32|0-37| 2-44| 2-14| 2-47| | 2-39| + | 964-1,003|0-32|0-45|0-37| |0-35|0-16| 2-16| 2-30| 2-35| | 2-21| + |1,004-1,060|0-54|0-37|0-49|0-40|0-49|0-24| 3-04| 2-55| 3-03| 2-34| 3-01| + |1,061-1,110|0-24|0-26|0-39|0-25|0-27|0-00| 1-35| 1-44| 2-02| 1-39| 1-41| + |1,111-1,238|0-36|0-34|0-57|1-12|0-41|0-02| 2-20| 2-36| 2-57| 3-31| 2-33| + |1,239-1,312|0-39|0-43|1-12|0-59|0-50|0-10| 2-47| 2-48| 3-18| 3-18| 3-01| + | 626-1,312|0-45|0-40|0-52|0-54|0-47|0-16| 3-03| 3-07| 3-20| 3-24| 3-09| + -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| + A| 171-1,312| [C]| | | | |0-15| 3-39| 3-43| 3-51| 3-50| 3-43| + l| 28-1,312| [C]| | | | |0-15| | | | | 5-01| + l| | | | | | | | | | | | | + =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| + + TABLE 27 SUMMARY PART 1 + + ===+===========+=======+==============+====+============+==+==+===+===+==| + | | | AVE. NO. | + W| | | OF MEN | + e| | DESCRIPTION | IN GANG | + i| |-------+--------------+----+------------+--+--+---+---+--| + g| | | |Ave.| | | | | | | + h| | | |air | | | | | | | + t| | | | | | | | | A | | + | | | |P | | | D| G | i | | + o| | | |r | | | r| r | r | | + f| | | |e | | S| i| o | | | + | | | |s | | h| l| u | T |T | + i| | | |s | | i| l| t | r |o | + r| Section | | |u | | e| i| i | a |t | + o| between |Length | |r |Method of | l| n| n | n |a | + n| rings |in feet| Material |e |Excavation | d| g| g | s |l | + ---+-----------+-------+--------------+----+------------+--+--+---+---+--| + {| 28-42 | 37.5|Rock |12 |[B]Breast |13| 4| 1| 1 |19| + O {| 43-58 | 40.0|Rock & gravel |12 | " |19| 2| 2| 2 |25| + r {| 59-153 | 237.5|Gravel & sand |16 | " |25| | 1| 4 |30| + d {| 154-170 | 42.5|Sand or silt, |18 | " |26| | 1| 5 |32| + i {| | | with piles | | | | | | | | + n {| 171-236 | 165.0|silt w/ piles |22 | " |22| | 1| 3 |26| + a {| 237-259 | 57.5|Silt |25 |[C]1 door |18| | 1| 3 |22| + r {| 260-625 | 915.0| " |27 | 1 " |18| | | 4 |22| + y {|-----------+-------+--------------+----+------------+--+--+---+---+--| + {| 28-625 |1,495.0| |25 | |19|.8|0.8|3.4|24| + ---+-----------+-------+--------------+----+------------+--+--+---+---+--| + Hvy| 626-1,312|1,717.5|Silt |28 | |25| | | 8 |33| + ---+-----------+-------+--------------+----+------------+--+--+---+---+--| + All| 28-1,312|3,212.5| |26 | |21| | | 5 |26| + ===+===========+=======+==============+====+============+==+==+===+===+==| + + TABLE 27 SUMMARY PART 2 + + ===+========+========+=======+======+====+=====+===============+========| + W | | | | UNAVOIDABLE DELAYS | + e | | | AVERAGE TIME |(NOT INCLUDED IN AVERAGE| + i o| | | PER RING. | TIME PER RING). | + g f| | |-------+------+----+-----+---------------+--------| + h |Average | Time | | | | | | | + t i| No. of |mucking,|Shoving| | | | | | + r| cubic | per | and | Erec-| | | | | + o| yards | cubic |mucking| tion |Lost| | | Time | + n|per ring| yard | [Z] | [A] |time|Total| Items |hrs min| + ---+--------+--------+-------+------+----+-----+---------------+--------| + {| 48.7 | 0-25 | 20-33 | 4-21|0-12|25-06|First bulkhead | 80-00| + O {| 44.2 | 0-46 | 33-44 | 4-44|1-15|39-43|Second bulkhead| 156-00| + r {| 39.0 | 0-12 | 8-06 | 2-23|0-30|10-59|Grouting rock | 280-00| + d {| 41.6 | 0-10 | 7-10 | 1-59|0-0 | 9-09| sections| | + i {| | | | | | |Blow-outs | 222-00| + n {| 42.6 | 0-10 | 7-23 | 2-35|0-05|10-03|Shield repairs | 326-40| + a {| 13.8 | 0-11 | 2-29 | 2-32|0-20| 5-21|Horz. timbers | 69-30| + r {| 3.6 | 0-06 | 0-40 | 2-39|0-14| 3-33| Total |1,134-10| + y {|--------+--------+-------+------+----+-----+---------------+--------| + {| 17.8 | 0-14 | 4-14 | 2-41|0-16| 7-11|Per ring | 0-53| + ---+--------+--------+-------+------+----+-----+---------------+--------| + Hvy| 10.6 | 0-4 | 0-56 | 1-57|0-16| 3-09| | | + ---+--------+--------+-------+------+----+-----+---------------+--------| + All| 14.1 | 0-10 | 2-28 | 2-18|0-15| 5-01| | | + ===+========+========+=======+======+====+=====+===============+========| + +[Z] Including time for jacks. + +[A] Including bolting time. + +[B] Excavating ahead of shield. + +[C] Shoving shield into silt with ... doors open. + +The average time taken for each operation at all the working faces is +given in Table 28. The work has been subdivided into the different kinds +of ground encountered. + +The progress, as shown by the amount of work done each month by each +shield, is given in Table 29. + +TABLE 28.--SHIELD-DRIVEN TUNNEL WORK.--TOTAL NUMBER OF RINGS ERECTED AND +SHIFTS WORKED BY ALL FOUR SHIELDS IN CONTRACTS GY-WEST AND GJ, AND THE +AVERAGE SIZE OF GANG, AMOUNT OF EXCAVATION AND TIME TAKEN PER RING FOR +THE VARIOUS OPERATIONS INVOLVED IN BUILDING TUNNEL IN EACH OF THE +SEVERAL KINDS OF GROUND ENCOUNTERED; ALSO THE EXTENT AND NATURE OF ALL +THE UNAVOIDABLE DELAYS. + + TABLE 28 PART 1 + + ===+===================+=====+========+======+==+====+====+====+====+====| + | | | | |A | AVE. NO. | + W| | | | |v | OF MEN | + e| | | | | | IN GANG | + i| | | | |a +----+----+----+----+----+ + g| | | | |i | | | | A | | + h| | | | |r | | D | G | i | | + t| | | |Total | | | r | r | r | | + | | | | |p | S | i | o | | | + o| |Total| Total |number|r | h | l | u | t | T | + f| | | | |e | i | l | t | r | o | + | Description | No. | No. | of |s | e | i | i | a | t | + i| | | | |s | l | n | n | n | a | + r| of | of | of |8-hour|u | d | g | g | s | l | + o| | | | |r |----+----+----+----+----+ + n| Material |rings| feet. |shifts|e |Unit|Unit|Unit|Unit|Unit| + ---+-------------------+-----+--------+------+--+----+----+----+----+----+ + {|Rock. | 165| 412.5| 597 |16| 18 | 9 |0.25| 1 | 28 | + O {|Rock and earth and | 177| 442.5| 500 |14| 22 | 5 |0.3 | 2 | 30 | + r {| rock and gravel.| | | | | | | | | | + d {|Sand and gravel | 188| 470.0| 241 |13| 24 | |0.6 | 3 | 27 | + i {| (unobstructed), NJ| | | | | | | | | | + n {|Sand and silt (with| 171| 427.5| 199 |22| 23 | |1.0 | 3 | 27 | + a {| piles.)| | | | | | | | | | + r {|Silt under R. R. | 396| 990.0| 355 |19| 27 | | | 3 | 30 | + y {| tracks, NY| | | | | | | | | | + {|Rip-rap and silt | 77| 192.5| 193 |23| 26 | | | 4 | 30 | + | under bulkhead.| | | | | | | | | | + i {| |-----+--------+------+--+----+----+----+----+----| + r {|Total mixed and | | | | | | | | | | + o {| difficult ground.|1,174| 2,935.0|2,085 |17| 22 | 4 |0.3 | 3 | 29 | + n {|-------------------+-----+--------+------+--+----+----+----+----+----+ + {|Silt--ordinary iron|1,302| 3,255.0| 676 |25| 22 | | | 4 | 26 | + ---+-------------------+-----+--------+------+--+----+----+----+----+----+ + Hvy|Silt--heavy iron. |2,209| 5,522.5| 791 |26| 25 | | | 8 | 33 | + ---+-------------------+-----+--------+------+--+----+----+----+----+----+ + |Silt--ord and heavy| | | | | | | | | | + |iron under river. |3,511| 8,777.5|1,467 |26| 24 | | | 6 | 30 | + |-------------------+-----+--------+------+--+----+----+----+----+----+ + |Grand total. |4,685|11,712.5|3,552 |21| 23 | 2 |0.2 | 4 | 29 | + ===+===================+=====+========+======+==+====+====+====+====+====| + + TABLE 28 PART 2 + + ====+====+=======+========+=======+=======+=============+========| + | | | | + | | | | + | | | | + | | | | + | | | | + | | | AVE. UNAVOIDABLE | + | | | DELAY PER | + | | AVERAGE TIME PER RING. | WORKING FACE. | + Cu. |Time|------------------------+-------+-------------+--------| + yd. |per |Shoving| | | | | Time | + per |cu. | and | | Lost | | Items |--------| + ring|yd. |mucking|Erecting| time | Total |not included |Ave unit| + ----+----+-------+--------+-------+-------| in previous |--------| + Unit|Unit|Hrs Min|Hrs Min |Hrs Min|Hrs Min| figures |Hrs Min | + | | K | L | M | | | | + ----+----+-------+--------+-------+-------+-------------+--------| + 51 |0-27| 25 15| 3 41 | 0 02| 28 58|1st Bulkhead |136 00 | + 45 |0-26| 19 31| 2 55 | 0 11| 22 37| 2d " |147 54 | + | | | | | | | | + 39 |0-12| 7 31| 2 24 | 0 20| 10 15|Grouting |246 00 | + | | | | | | | | + 43 |0-09| 6 46| 2 24 | 0 09| 9 19|Blow-outs | 91 11 | + | | | | | | | | + 42 |0-06| 4 09| 2 51 | 0 10| 7 10|Miscellaneous|230 33 | + | | | | | | | | + 43 |0-21| 14 47| 3 41 | 1 34| 20 02|Total |851 38 | + | | | | | | | | + ----+----+-------+--------+-------+-------+-------------+--------| + | | | | | | | | + 43 |0-18| 11 02| 2 54 | 0 16| 14 12| | | + ----+----+-------+--------+-------+-------+-------------+--------| + 12 |0-07| 1 20| 2 35 | 0 14| 4 12| | | + ----+----+-------+--------+-------+-------+-------------+--------| + 12 |0-05| 0 58| 1 44 | 0 10| 2 52| | | + ----+----+-------+--------+-------+-------+-------------+--------| + | | | | | | | | + 12 |0-06| 1 09| 2 05 | 0 12| 3 26| | | + ----+----+-------+--------+-------+-------+-------------+--------| + 20 |0-11| 3 33| 2 15 | 0 13| 6 01| | | + ----+----+-------+--------+-------+-------+-------------+--------| + + Average delay per ring--0 hrs. 44 min. + Average rings built by one shield = 1,146¼. + + Average time per ring. 6 hr 01 min + Delays. 44 min + ----------- + Total time per ring. 6 hr 45 min + +NOTE.--The "unavoidable delays" included in this table do not embrace +the periods during which the work was at complete or partial standstill +due to experiments and observations, shortage of iron due to change of +design, and holidays. + + K-Including time for jacks. + + L-Including time spent by the whole gang on bolting; in + addition to this there was a small gang which spent its + whole time bolting. + + M-Chiefly due to breakdowns of hydraulic lines and + erector. + +_Air Pressure._--The air pressure varied from 17 to 37 lb. Behind the +river line it averaged 17 lb. and under the river 26 lb. Behind the +river lines the pressure was generally kept about equal to the water +head at the crown, except where at Weehawken, as previously described, +this was impossible. + +In the silt the pressure was much lower than the hydrostatic head at the +crown, but if it became necessary to make an excavation ahead of the +shield, for example at the junction of the shields, the air pressure +required was about equal to the weight of the overlying material, +namely, the water and the silt, as the silt, which weighed from 97 to +106 lb. per cu. ft. and averaged 100 lb. per cu. ft., acted like a +fluid. + + TABLE 29.--MONTHLY PROGRESS OF SHIELD-DRIVEN TUNNEL WORK. + + =====+=============================+=============================+ + | North Manhattan. | South Manhattan. | + +-----------------------------+----------------------+------+ + | Number of | Station |Lin. | Number of | Station |Lin. | + | rings | of |ft. | rings | of |ft. | + | erected. | leading |for | erected. | leading |for | + +-----------+ ring. |month.+-----------+ ring. |month.| + |For | To | | |For |To | | | + Month|month|date | | |month|date | | | + -----+-----+-----+----------+------+-----+-----+----------+------+ + 1905 | | | | | | | | | + May | 26 | 26|200 + 83.7| 63.7 | | | | | + June | 26 | 52|201 + 49.0| 65.3 | | | | | + July | 28 | 80|202 + 19.2| 70.2 | | | | | + Aug | 26 | 106|202 + 84.3| 65.1 | | | | | + Sept | 21 | 127|203 + 36.8| 52.5 | 31 | 31|200 + 96.4| 76.4 | + Oct | 25 | 152|203 + 99.4| 63.6 | 45 | 76|202 + 09.2|112.8 | + Nov | 31 | 183|204 + 76.9| 77.5 | 31 | 107|202 + 86.5| 77.3 | + Dec | 59 | 242|206 + 24.6|147.7 | 34 | 141|208 + 71.8| 85.3 | + 1906 | | | | | | | | | + Jan | 94 | 336|208 + 59.8|235.2 | 27 | 168|304 + 39.4| 67.6 | + Feb | 78 | 414|210 + 54.9|195.1 | 64 | 232|205 + 99.6|160.2 | + Mar | 56 | 470|211 + 95.2|140.3 | 96 | 328|208 + 39.9|240.3 | + April| 119 | 589|214 + 93.0|297.8 | 84 | 412|210 + 59.1|210.2 | + May | 129 | 718|218 + 15.7|322.7 | 70 | 482|212 + 25.3|165.2 | + June | 218 | 936|232 + 60.9|545.2 | 140 | 622|215 + 75.5|350.2 | + July | 155 |1,091|227 + 48.5|387.6 | 82 | 704|217 + 80.7|205.2 | + Aug | 145 |1,236|231 + 11.2|362.7 | 134 | 838|221 + 15.8|335.1 | + Sept | 89 |1,325|233 + 34.1|222.9 | 168 |1,006|225 + 35.8|420.0 | + Oct | | | | | 105 |1,111|227 + 98.6|262.8 | + Nov | | | | | 7 |1,118|228 + 16.8| 18.2 | + =====+=====+=====+==========+======+=====+=====+==========+======+ + + =====+=============================+============================+======== + | North Weehawken. | South Weehawken. | + +-----------------------------+----------------------------+Average + | Number of | Station |Lin. | Number of | Station |Lin. |progress + | rings | of |ft. | rings | of |ft. |per + | erected. | leading |for | erected. | leading |for |shield + +-----------+ ring. |month.+-----------+ ring. |month|lin. ft. + |For | To | | |For |To | | |per + Month|month|date | | |month|date | | |month. + -----+-----+-----+----------+------+-----+-----+----------+-----+-------- + 1905 | | | | | | | | | + May | | | | | | | | | 15.9 + June | 24 | 24|260 + 76.6| 59.3 | 12 | 12|260 + 70.0| 30.0| 38.6 + July | 12 | 36|260 + 46.6| 30.0 | 15 | 27|260 + 32.4| 37.6| 34.4 + Aug | 15 | 51|260 + 09.1| 37.5 | 16 | 43|260 + 07.4| 25.0| 31.9 + Sept | 1 | 52|260 + 06.6| 2.5 | 18 | 61|259 + 47.2| 60.2| 47.9 + Oct | 10 | 62|259 + 81.5| 25.1 | 20 | 81|258 + 97.2| 50.0| 62.9 + Nov | 29 | 91|259 + 09.0| 72.5 | 39 | 120|257 + 99.7| 97.5| 81.2 + Dec | 46 | 137|257 + 94.0|115.0 | 77 | 197|256 + 07.1|192.6| 135.1 + 1906 | | | | | | | | | + Jan | 77 | 214|256 + 01.4|192.6 | 73 | 270|254 + 24.6|182.5| 169.4 + Feb | 133 | 347|252 + 68.6|332.8 | 165 | 435|250 + 11.7|412.9| 275.2 + Mar | 142 | 489|249 + 13.3|355.3 | 111 | 546|247 + 34.0|277.7| 253.4 + April| 32 | 521|248 + 33.3| 80.0 | 78 | 624|245 + 38.9|195.1| 195.7 + May | 121 | 642|245 + 30.6|302.7 | 2 | 626|245 + 33.9| 5.0| 198.9 + June | 162 | 804|241 + 25.3|405.3 | 157 | 788|241 + 41.1|392.8| 423.4 + July | 113 | 917|238 + 42.4|282.9 | 118 | 901|238 + 45.9|295.2| 292.7 + Aug | 138 |1,055|234 + 97.1|345.3 | 140 |1,041|234 + 95.8|850.1| 348.3 + Sept | 55 |1,110|233 + 59.5|137.6 | 177 |1,218|230 + 52.8|443.0| 305.9 + Oct | 1 |1,111|233 + 57.0| 2.5 | 94 |1,312|228 + 16.8|236.0| 125.3 + Nov | 9 |1,120|233 + 34.1| 22.9 | | | | | 10.3 + -----+-----+-----+----------+------+-----+-----+----------+-----+-------- + +A ½-in. air line was taken direct from the working chamber to the +recording gauges in the engine-room, which enabled the engine-room force +to keep a constant watch on the air conditions below. To avoid undue +rise of pressure, a safety valve was set on the air line at each lock, +set to blow off if the air pressure rose above that desired. The +compressor plant was ample, except, as before described, when passing +the gravel section at Weehawken. + +Records were kept of the air supply, and it may be said here that the +quantity of free air per man per hour was in general between 1,500 and +5,000 cu. ft., though in the open gravel where the escape was great it +was for a time as much as 10,000 cu. ft. For more than half the silt +period it was kept between 3,000 and 4,000 cu. ft., but when it seemed +proved beyond doubt that any quantity more than 2,000 cu. ft. had no +beneficial effect on health, no attempt was made to deliver more, and on +two separate occasions for two consecutive weeks it ran as low as 1,000 +cu. ft. without any increase in the number of cases of bends. + +The amount of CO_{2} in the air was also measured daily, as the +specifications called for not more than 1 part of CO_{2} per 1,000 parts +of air. The average ranged between 0.8 and 1.5 parts per 1,000, though +in exceptional cases it fell as low as 0.3 and rose to 4.0. The air +temperature in the tunnels usually ranged from 55° to 60° Fahr., which +was the temperature also of the surrounding silt, though at times, in +the earlier parts of the work when grouting extensively in long sections +of the tunnel in rock, it varied from 85° to 110° Fahr. + +_Grouting._--Grout of one part of Portland cement to one part of sand by +volume was forced outside the tunnel lining by air pressure through +1½-in. tapped and plugged grout holes formed in each segment for this +purpose, wherever the ground was not likely to squeeze in upon the metal +lining as soon as this was erected. That is to say, it was used +everywhere up to the river line; between river lines it was not used +except at the New York bulkhead wall in order to fill voids in the +rip-rap, and at the point of junction of the shields where the space +between the metal lining and the shield skins outside it was grouted. +Cow Bay sand was used, and it had to be screened to remove particles +greater than 1/10 in. in diameter, which would choke the valves. For +later grouting work, namely, in the top of the concrete lining inside +the metal lining, Rockaway Beach sand was used. This is very fine, and +did not need screening; it cost more, but the saving of screening and +the non-blocking of valves, etc., resulted in a saving. + +The grout was mixed in a machine shown in Fig. 2, Plate XLI, which is a +view of the grouting operation. + +The grout pipes were not screwed directly into the tapped hole in the +segments, but a pipe containing a nipple and valve was screwed into the +grout hole and the grout pipe screwed to the pipe. This prevented the +waste of grout, enabled the valve to be closed and the grout pipe +disconnected, and the pipe to be left in position until the grout had +set. In the full rock section, 20 or 30 rings were put in without +grouting; then the shield was stopped, the last two or three rings were +detached and pulled ahead by the shield, a masonry stop-wall was built +around the outside of the last ring left in, and the whole 20 or 30 +rings were grouted at one time. In the landward silt and gravel each +ring had to be grouted as soon as the shield had left it, in order to +avoid the flattening caused by the weight coming on the crown while the +sides were as yet unsupported. The grout was prevented from reaching the +tail of the shield by plugging up the space with empty cement bags, +assisted by segmental boards held against the face of the leading ring +by U-shaped clamps, fitting over the front circumferential flange of the +ring and the boards, and tightened by wedges. The air pressure varied +between 70 and 100 lb. per sq. in. above normal. + +The force consisted of one pipe-fitter and one or two laborers employed +part of their time. When a considerable length was being grouted at a +time, as in the full rock section, many laborers were employed for a +short period. + + +Transportation and Disposal. + +The transportation and disposal will be described under the following +headings: + + Receipt and Unloading of Materials, + Surface Transportation, + Tunnel Transportation, + Disposal. + +_Receipt and Unloading of Materials._--At the Manhattan Shaft the +contractor laid a spur siding into the yard from the freight tracks of +the New York Central Railroad, which immediately adjoins the yard on the +west. There was also wharfage on the river front about 1,500 ft. away. + +At the Weehawken Shaft there were four sidings from the Erie Railroad +and one from the West Shore Railroad. Access to the river was gained by +a trestle direct from the yard, and Baldwin Avenue adjoined the yard. + +All the iron lining arrived by railroad. It was unloaded by derricks, +and stacked so that it was convenient for use in the tunnel. The +Manhattan derricks were a pair of steel ones with 39-ft. booms, worked +by a 30-h.p., 250-volt, electric motor. There was also a stiff-leg +derrick with 50-ft. boom, on a platform near the shaft, which was worked +by a 40-h.p., 250-volt motor. At Weehawken there were two 45-ft. boom, +stiff-leg derricks of 2 tons capacity, one worked by a 42-h.p. +Lidgerwood boiler and engine, and the other by a 25-h.p., 250-volt, +electric motor. These derricks were set on elevated trestles near the +Erie Railroad sidings. There was a 50-ft. stiff-leg derrick with a +70-h.p. Lidgerwood boiler and engine near the cement warehouse on the +West Shore Railroad. + +The storage area for iron lining was 1,800 sq. ft. at Manhattan and +63,000 sq. ft. at Weehawken; the maximum quantity of lining in storage +at any one time was 150 rings at Manhattan and 1,200 rings at Weehawken. + +The cement, which was issued and sold by the Company to the contractor, +was kept in cement warehouses; that at the New York side was at Eleventh +Avenue and 38th Street, or some 1,200 ft. from the shaft, to which it +was brought by team; that at Weehawken was adjacent to the shaft, with a +2-ft. gauge track throughout it and directly connected with the shaft +elevator. + +_Surface Transportation._--In the early days the excavation was handled +in scale-boxes of 1 cu. yd. capacity which were hoisted up the shafts by +a derrick, but, when the iron period began, two-cage elevators were put +in at each shaft. They were worked by a single, friction-drum, +Lidgerwood, steam hoisting engine of 40 h.p. + +All materials of construction were loaded on cars on the surface at the +point where they were stored, and hauled on these to the elevators, +sent down the shaft, and taken along the tunnels to the desired point +without unloading. + +The narrow-gauge railway on the surface and in the tunnel was of 2-ft. +gauge with 20-lb. rails. About 70 flat cars and 50 mining cars were used +at each shaft. On the surface at Manhattan these were moved by hand, but +at Weehawken, where distances were greater, two electric locomotives on +the overhead trolley system were used. + +_Tunnel Transportation._--The mining cars shown in Fig. 19 were of 1¼ +cu. yd. capacity. The short wheel base and unbalanced loading caused a +good many upsets, but they were compact, easily handled, and could be +dumped from either side or end. + +[Illustration: MUCK CAR (AS USED IN RIVER TUNNELS) CAPACITY 5,000 LBS. +OR 1¼ CU. YD. FIG. 19.] + +The flat cars shown in Fig. 20 were of 3 tons capacity, and could hold +two tunnel segments. As the working face was down grade from the shafts, +the in-bound cars were run by gravity. For out-bound cars a cable +haulage system was used, consisting of double-cylinder, Lidgerwood, +single friction-drum, hoisting engines (No. 32) of 6 h.p., with +cylinders 5 in. in diameter and 6 in. stroke and drums 10 in. in +diameter. These were handily moved from point to point, but, as there +was no tail rope, several men had to be used to pull the cable back to +the face. After the second air-lock bulkhead walls had been built, a +continuous-cable system, worked electrically, was put in each tunnel +between the first and second air-locks. + +The engine consisted of an electric motor driving a 3-ft. 6-in. drum +hoist around which a ¾-in. steel wire cable passed three times. The +cable was led around a sheave, down the tunnel on the right side of the +in-bound track, and returned on the left side of the out-bound track. It +was then carried around a set of sheaves, where a tension of 1,000 lb. +was supplied by a suspended weight which acted on a sheave with a +sliding axle on the tension carriage. The cable was supported throughout +its length on 8-in. pulleys set in the floor at 50-ft. intervals. All +the guide sheaves were 36 in. in diameter. + +[Illustration: FLAT CAR FOR TUNNEL SEGMENTS CAPACITY 6,000 LBS. FIG. +20.] + +Each car was attached to the cable by a grip at its side. This was +fastened and unfastened by hand, but was automatically released just +before reaching the turn in the cable near each lock. This system could +haul without difficulty an unbalanced load of 10 muck cars, spaced 100 +ft. apart, up a 2% grade. The cable operated over about 1,000 ft. of +tunnel, the motor being placed at the top of the grade. The driving +motor was of the semi-armored, 8-pole, series-wound type, rated at 25 +h.p., 635 rev. per min., and using direct current at 220 volts. The +speed of handling the cars was limited by their having to pass through +the air-locks on a single track. As many as 106 cars have been hauled +each way in one 8-hour shift. + +_Disposal._--At Manhattan the tunnel muck was carried from the elevator +over the upper level of the yard trestle and dumped into bins on the 33d +Street side, whence it was teamed to the public dump at 30th Street and +North River. At Weehawken the rock excavation was removed by the Erie +Railroad on flat cars on which it was dumped by the tunnel contractor, +but all the silt muck was teamed away to some marshy ground where +dumping privileges were obtained. + +The typical forces employed on transportation were as follows: + +_Receipt and Unloading of Material: Surface Transportation and +Disposal._ + +At Manhattan Shaft, on 10-hour shifts: + + 2 Engineers on derricks. @ $3.00 per day. + 2 Foremen. " 3.25 " " + 15 Laborers loading and unloading iron. " 1.75 " " + 7 Laborers on disposal. " 1.75 " " + 6 Teams. " 7.50 " " + +At Weehawken Shaft, on 10-hour shifts: + + 3 Engineers on derricks and locomotives. @ $3.00 per day. + 16 Laborers loading and unloading iron. " 1.75 " " + 3 Foremen. " 3.50 " " + 11 Laborers on disposal. " 1.75 " " + 6 Teams on disposal. " 6.50 " " + +Tunnel Transportation (Including Shaft Elevator): + +Shaft elevators and to and from the first air-lock on 10-hour shift: + + 2 Engineers. @ $3.00 per day. + 2 Signalmen. " 2.00 " " + 1 Foreman. " 3.00 " " + 12 Laborers. " 1.75 " " + +Between first lock and working face, on 8-hour shifts, the force varied: + + From 1 to 3 (average 2) Hoist engineers @ $3.00 per day. + From 0 to 2 (average 1) Lockman " 2.75 " " + From 1 to 2 (average 2) Trackmen " 3.00 " " + From 2 to 7 (average 4) Cablemen + (pulling back cable) " 3.00 " " + +_Pumping._--The water was taken out of the invert by a 4-in. blow-pipe +which was always kept up to a point near the shield and discharged into +the sump near the shaft. + +When the air pressure was removed and the blow-pipe device, +consequently, was unavailable, small Cameron pumps, driven by compressed +air, and having a capacity of about 140 gal. per hour, were used, one +being set up wherever it was necessary to keep the invert dry; for +example, at points where caulking was in progress. + +_Lighting._--The tunnels were lighted by electricity, the current being +supplied, at a pressure of 250 volts, from the dynamos in the +contractor's power-house. + +Two 0000 wire cables were used as far as the second air-locks, about +1,650 ft. from the power-house, on each side; and beyond that point, to +the junction of the shields (about 1,750 ft.), 00 and 0 wires were used. +These cables also carried the current for the cable haulage system. Two +rows of 16-c.p. lamps, provided with reflectors, were used in each +tunnel; one row was along the side just above the axis, with the lights +at about 30-ft. intervals; the other along the crown, with the lamps +halfway between the side lamps, also at 30-ft. intervals. At points +where work was in progress three groups of 5 lights each were used. The +tunnels as a whole were well lighted, and in consequence work of all +kinds was much helped. + +_Period No. 2._--_Caulking and Grummeting._--_November, 1906, to June, +1907._--After the metal lining had been built completely across the +river in both tunnels, the work of making it water-tight was taken up. +This consisted in caulking into the joints between the plates a mixture +of sal-ammoniac and iron borings which set up into a hard rusty mass, +and in taking out each bolt and placing around the shank under the +washer at each end a grummet made of yarn soaked in red lead. These +grummets were made by the contractor on the works, and consisted of +three or four strands of twisted hemp yarn, known as "lath yarn," making +up a rope-like cross-section about ¼ in. in diameter. Usually, one of +these under each washer was enough, but in wet gravel, or where bolts +were obliquely in the bolt-holes, two were used at each end. After +pulling the grummets in, all the nuts were pulled up tight by wrenches +about 3 ft. long, with two men on one wrench. Bolts were not passed as +tight unless the nut resisted the weight of an average man on a +2½-ft. wrench. + +Before putting in the caulking mixture, the joints were carefully +scraped out with a special tool, cleaned with cotton waste, and washed +with a stream of water. The usual mixture for sides and invert was about +2 lb. of sal-ammoniac and 1 lb. of sulphur to 250 lb. of iron filings or +borings. In the arch, 4 lb. of sal-ammoniac and 3 lb. of sulphur to 125 +lb. of filings was the mixture. A small hand-hammer was used to drive +the caulking tool, but, in the sides and invert, air hammers were used +with some advantage. The success of work of this kind depends entirely +on the thoroughness with which the mixture is hammered in; and the +inspection, which was of an exceedingly monotonous nature, called for +the greatest care and watchfulness on the part of the Company's forces, +especially in the pocket iron, where each bolt had to be removed, the +caulking done at the bottom of the pockets put in, the bolts replaced; +and the rest of the pockets filled. The results have been satisfactory, +as the leakage under normal air and prior to placing the concrete +averaged about 0.14 gal. per lin. ft. of tunnel per 24 hours, which is +about 0.0035 gal. per lin. ft. of joint per 24 hours. With each linear +foot of joint is included the leakage from 1.27 bolts. Afterward, when +the concrete lining was in, the leakage was found to be about 0.05 to +0.06 gal. per lin. ft. of tunnel per 24 hours, which compares favorably +with the records of other lined tunnels. The typical gang employed on +this work was as follows: + +_In Pocket Iron:_ + + 1 General foreman @ $5.00 per day. + 1 Mixer " 3.00 " " + 1 Nipper " 3.00 " " + 5 Caulkers " 3.00 " " + 10 Grummeters " 3.00 " " + +_In Pocketless Iron:_ + + 1 General foreman @ $5.00 per day. + 1 Mixer " 3.00 " " + 1 Nipper " 3.00 " " + 3 Caulkers " 3.00 " " + 12 Grummeters " 3.00 " " + +The average amount of caulking and grummeting done per shift with such a +gang was (with pocketless grooves), 348 lin. ft. of joint and 445 bolts +grummeted; and in pocket iron: 126 lin. ft. of joint and 160 bolts +grummeted. + +The caulking and grummeting work was finished in June, 1907, this +completing the second period. + +_Period No. 3._--_Experiments, Tests, and Observations._--_April, 1907, +to April, 1908._--The third period, that of tests and observations in +connection with the question of foundations, is dealt with in another +paper. It occupied from April, 1907, to November, 1908. The results of +the information then gathered was that it was not thought advisable to +go on with the foundations. + +_Period No. 4._--_Capping Pile Bores, Sinking Sumps, and Building +Cross-Passages._--_April, 1908, to November, 1908._--In order to reduce +the leakage from the bore segments to the least possible amount before +placing the concrete lining, it was decided to remove the plugs and +replace them with flat cover-plates; these have been described before, +together with the filling of Bore Segments No. 2 with mortar to reduce +the leakage around the distance piece. + +During this period the turnbuckles to reinforce the broken plates were +put in, and the sump sunk at the lowest point of the tunnel. These sumps +have been described in a previous part of this paper; they were put down +without trouble. As much as possible of the concrete lining was put in +before the lining castings were taken into the tunnel, as the space +inside was very restricted. The first lining casting was bolted to the +flat flanges of the sump segment, the bolts holding the latter to the +adjacent segments were removed, and the whole was forced down with two +of the old shield jacks, taking a bearing on the tunnel. The two +together exerted a pressure of about 150 tons. The plugs in the bottom +of the sump segment were taken out, and pipes were put in, through which +the silt squeezed up into the tunnel and relieved the pressure on the +sump segment. + +If the silt did not flow freely, a water-jet was used. The sump was kept +plumb by regulating the jacks. In this way the sump was sunk, adding +lining sections one by one, and finally putting on the top segment, +which was composed of three pieces. + +The time taken to sink one sump was about 4 days, working one 8-hour +shift per day, and not counting the time taken to set up the jacks and +bracing. The sinking of each section took from 4 to 6 hours. The air +pressure was 25 lb. and the hydrostatic head 41 lb. per sq. in. The +force was 1 assistant superintendent at $6.00 per day, 1 foreman at +$4.50, and 6 laborers at $3.00 per day. + +_Cross-Passages._--It was during this period that the five +cross-passages previously mentioned were built. In the case of those in +the rock, careful excavation was needed so as to avoid breaking the iron +lining. Drilling was done from both ends, the holes were closely spaced, +and about 2 ft. 6 in. deep, and light charges of powder were used. The +heading, 5 by 7 ft. in cross-section, was thus excavated in five +lengths, with 24 holes to a length, and about 23 lin. ft. of hole per +yard. About 5.3 lb. of powder per cu. yd. was used. The sides, top, and +bottom were then drilled at a very sharp angle to the face and the +excavation was trimmed to the right size. This widening out took about +7½ ft. of hole per cu. yd., and 0.9 lb. of powder. + +In the passages in silt the excavation had to be 12 ft. wide and 13 ft. +8 in. high to give enough room inside the timbers. The plates at one end +of the passage were first removed. An air pressure of 17 lb. was +carried, which was enough to keep the silt from squeezing in and yet +left it soft enough to be chopped with a spade. + +A top heading, of full width and 6 ft. 8 in. high, was first taken out, +and the roof was sheathed with 2-in. boards held by 10 by 10-in. head +trees at 3-ft. centers, with 10 by 10-in. side trees. The lower 7 ft. of +bench was then taken out, a tight floor of 6 by 6-in. cross-timber was +put in, and also longer side trees, the head trees being temporarily +held by two longitudinal 10 by 10-in. stringers blocked in place. The +bulk of the space between the side trees was filled with 10 by 10-in. +posts and blocking. The plates at the other end of the passage were then +taken out from the other tunnel. + +After the excavation was out, the outer reinforced concrete lining was +built. Rough forms were used, as the interior surfaces of the passages +were to be rendered with a water-proofing cement. A few grout pipes +were built in, and all voids outside the concrete were grouted. Grouting +was also done through the regular grout holes of the metal lining around +the openings. + +In the case of the most westerly of the cross-passages at Weehawken, +which was in badly seamed rock carrying much water, a steel +inter-lining, rather smaller than the concrete, was put in. The space +between the concrete and the steel was left open, so that water coming +through the concrete lining was stopped by the steel plate. This water +was led back to the shield chamber in a special drain laid in the bench +of the river tunnel and behind the ducts. From the shield chamber the +water ran with the rest of the drainage from the Weehawken Land Tunnels +to the Weehawken Shaft sump. + +[Illustration: TYPICAL CROSS-SECTIONS SHOWING SUCCESSIVE STAGES IN +PLACING CONCRETE IN RIVER TUNNELS FIG. 21.] + +_Period No. 5._--_Placing the Concrete Lining._--_November, 1908, to +June, 1909._--During the fifth period the concrete lining was put in. +This lining was placed in stages, as follows: First, the invert; second, +the duct bench; third, the arch; fourth, the ducts; and fifth, the face +of the bench. This division can be seen by reference to Fig. 21. + +All the work was started on the landward ends and carried toward the +middle of the river from both sides. Except where the Weehawken force +passed the lowest point of the tunnel, which is at Station 241 or nearly +900 ft. to the west of the middle of the river, all the work was down +grade. + +Before any concrete was placed, the surface of the iron was cleaned with +scrapers and wire brushes, and washed with water. Any leaks in the +caulking and grummeting (finished by June, 1907, and therefore all more +than 12 months old) were repaired. All the grout hole plugs were +examined, and the plugs in any leaking ones were taken out, smeared +with red lead, and replaced. The leakage in the caulking was due to the +fact that the tunnel had been settling slightly during the whole 12 +months of pile tests, and, therefore, had opened some of the joints. +After the caulking had been repaired and the surface thoroughly cleaned, +the flanges were covered with neat cement (put on dry or poured on in +the form of thick grout) just before the concrete was placed. + +_Invert Concrete._--The form used for the landward type of concrete, +that is, the one with a middle drain, consisted of a frame made of a +pair of trussed steel rails on each side of the tunnel and connected at +intervals with 6 by 6-in. cross-timbers; two "wing forms" were hung from +this frame by adjustable arms. These wings formed the curved sides of +the invert, the lip, and the form for the middle drain. The whole form +was supported on three wheels, two on the rear end running on a rail +laid on the finished concrete, and the third in front attached to the +frame by a carriage and running on a rail temporarily laid on the iron +lining. The form was braced from the iron lining by 6 by 6-in. blocks. + +For the soft-ground type of invert, namely, the one without the middle +drain, a form of the same general type was used, except that the form +for the middle drain was removed. After the form had been in use for +some time, "key pieces" (made of strips of wood about 1 ft. 3 in. in +length and 3 by 3 in. in cross-section) were nailed circumferentially on +the under side of the wings at 2-ft. intervals. This was done because, +at the time, it was not known whether ballasted tracks or some form of +rigid concrete track construction would be adopted, and, if the latter, +it was desirable not to have the surface smooth. + +The concrete was received in cars at the rear end of the form and dumped +on a temporary platform. It was then loaded into wheel-barrows on the +runways, as shown in Fig. 22. The concrete was thrown from the barrows +into the invert, where it was spaded and tamped. + +In cases where there was steel-rod reinforcement, the concrete was first +brought up to the level of the underside of these rods, which came +between the wings; the rods were laid in place, and then more concrete +was placed over the rods and brought up to the level of the bottom of +the wings. Where there was no reinforcement, the concrete was brought up +in one lift. + +[Illustration: CONCRETE FORM STANDARD IN RIVER TUNNELS FIG. 22.] + +After this was finished, the concrete behind the wings was placed, +thoroughly spaded and tamped, and, where there were longitudinal +reinforcing rods, these were put in at their proper level. Where there +were circumferential rods, the 16-ft. rods had already been put in when +the lower part of the concrete was placed. As the invert was being +finished off, the 8-ft. rods were embedded and tied in position. + +The longitudinal rods were held in place at the leading end of each +length of arch by the wooden bulkhead, through which holes were drilled +in the proper position. At the rear end they were tied to the rods +projecting from the previous length. The quantity of water used in +mixing the invert concrete needed very nice adjustment; if too wet, the +middle would bulge and rise when the weight of the sides came on it; +and, if too dry, it would not pack properly between the flanges of the +iron lining. The difficulties as to this were often increased by the +flow of accumulated leakage water from the tunnel behind on the concrete +while it was being put in. To prevent this, a temporary dam of sand bags +was always built across the last length of finished invert concrete +before beginning a new length. A sump hole, about 4 by 1 ft. and 1 ft. +deep, was left every 800 ft. along the tunnel, and a small Cameron pump +was put there to pump out the water. + +The invert forms were left in place about 12 hours after the pour was +finished. The average time taken to fill a length of 30 feet was 7 +hours, the form was then left 12 hours, and it took 2 hours to set it up +anew. The total time for one length, therefore, was 21 hours, equal to +34 ft. per 24 hours. At one place, a 45-ft. form was used, and this gave +an average speed of 45 ft. per 24 hours. + +An attempt was made to build the invert concrete without forms (seeing +that a rough finish was desired, as previously explained, to form a key +for possible sub-track concrete), but it proved a failure. + +The typical working force (excluding transport) was as follows: + + 1 Foreman @ $3.25 per shift. + 2 Spaders " 2.00 " " + 9 Laborers " 1.75 " " + +The average time taken to lay a 30-ft. length of invert was 7 hours; the +two spaders remained one hour extra, smoothing off the surface. + +For setting the form, the force was: + + 1 Foreman @ $4.50 per shift. + 5 Carpenters " 3.25 " " + 6 Carpenters' helpers " 2.25 " " + +The average time taken to erect a form was 2 hours, 1 carpenter and 1 +helper remaining until the concrete was finished. + +_Duct Bench Concrete._--The duct bench (as described previously) is the +portion of the concrete on which the ducts are laid. The exact height of +the steps was found by trial, so as to bring the top of the ducts into +the proper position with regard to the top and the face of the bench. + +Both kinds of duct bench forms were of the same general type. A drawing +of one of them is shown on Plate XLII. The form consisted of a skeleton +framework running on wheels on a track at the level of the temporary +transportation tracks. The vertical faces of the steps were formed by +boards supported from the uprights by adjustable arms. The horizontal +surfaces were formed by leveling off the concrete with a shovel at the +top of the vertical boards. Where the sheets of expanded metal used for +bonding came at a step, the lower edge of the boards forming the back of +the step was placed 1 in. above the one forming the front of it; but, +when the expanded metal came in the middle of a step, a slot 1 in. wide +was left at that point to accommodate it. + +A platform was formed on the top of the framework for the form, and on +this a car forming a sort of traveling stage was run. There was ample +room to maintain traffic on a single track through the form. A +photograph of the form is shown in Fig. 1, Plate XLIII. + +The concrete, for the most part, was received at the form in ¾-cu. yd. +dumping buckets. The buckets were lifted by the rope from a small +hoisting engine. This rope passed over a pulley attached to the crown of +the tunnel and dumped into the traveling stage on the top of the form. +In this the concrete was moved along to the point where it was to be +deposited, and there it was thrown out by shovels into the form below. +For a portion of the period, while the duct bench concrete was being +laid, it was not necessary to maintain a track for traffic through the +form and, during that period, the concrete for the lower step was placed +from below the form, the concrete being first dumped on a temporary +stage at the lower track level. + +Owing to the horizontal faces of the steps being uncovered, there was a +tendency for the concrete there to rise when concrete was placed in the +steps above. For this part of the work, also, it was necessary to see +that the concrete was not mixed too wet, for, when that was the case, +the concrete in the upper steps was very apt to flow out at the top of +the lower one. At the same time, there was the standing objection to the +mixture being too dry, namely, the responsibility of getting a +sufficient amount of spading and tamping done. Particulars of the exact +quantity of water used are given later in describing "Mixing." Fig. 2, +Plate XLIII, illustrates the process of laying. + +In the section of the tunnel in which there were circumferential +reinforcement rods in the duct bench, the rods were in place before the +laying commenced, as they had been placed with the invert concrete. The +circumferential reinforcing rods in the arch came down into the upper +part of the duct bench concrete; these rods were put in position and +tied to the iron lining in the crown at the same time as the duct bench +concrete was being finished off. Openings for the manholes were left in +the duct bench at the regular stationing. + +The average time taken to fill a length of 35 ft. was about 6 hours; the +form was then left in position for about 8 hours--usually enough to let +the concrete set properly--and then moved ahead; it then took about 3 +hours to set it up again ready to continue work. The total time for a +length, therefore, was about 17 hours, equal to an average progress of +about 49 ft. per day. The average force engaged in duct bench concrete +(not including transport) was: + + 1 Foreman @ $3.25 per day. + 2 Spaders " 2.00 " " + 9 Laborers " 1.75 " " + +_Arch Concrete._--By far the greater part of the arch work was put in +with traveling centers before the face of the bench was built, in which +case the whole of the arch was built at once. A short length of arch at +each end of the tunnel was built after the face of the bench, in which +case the haunches or lower 5 ft. were laid first and the upper part of +the arch later. + +The first traveling centers were used on the New York side, and were 50 +ft. long. The laggings were of 4-in. yellow pine, built up in panels 10 +ft. long and 16 in. wide for the sides, and solely longitudinal lagging +5 ft. long for the key. + +It was pretty certain that the results to be obtained from forms of such +a length would not be satisfactory, and this was pointed out to the +contractor, who, however, obtained permission to use them on trial. +Grout pipes were built in, as it was not likely that the concrete could +be packed tightly into the upper part of the lining. + +[Illustration: PLATE XLIII. TRANS. AM. SOC. CIV. ENGRS. VOL. LXVIII, No. +1155. HEWETT AND BROWN ON PENNSYLVANIA R. R. TUNNELS: NORTH RIVER +TUNNELS. FIG. 1.] + +[Illustration: PLATE XLIII. TRANS. AM. SOC. CIV. ENGRS. VOL. LXVIII, No. +1155. HEWETT AND BROWN ON PENNSYLVANIA R. R. TUNNELS: NORTH RIVER +TUNNELS. FIG. 2.] + +After about 300 lin. ft. of arch had been built with these forms, a test +hole was cut out and large voids were found, and, to confirm this, +another hole was cut, and similar conditions observed. + +The results were so unsatisfactory that orders were given that the use +of longitudinal key lagging should be discontinued, and cross or block +lagging used instead. These block laggings were 6 in. in length (in the +direction of the tunnel) and 2 ft. in width; at the same time, the +system of grout pipes was changed. This will be described later under +"Grouting." It was soon found that with block lagging a better job could +be made of packing the concrete up into the keys, but the time taken to +"key up" a 50-ft. length was so great that the rest of the arch had set +by the time the key was finished. Despite a lot of practice, this was +the case, even in the unreinforced type. When the reinforcing rods were +met, the time for keying up became still greater, and therefore the +contractor was directed to shorten the forms to 20-ft. lengths. A +typical working force for a 50-ft. length was: + + 1 Foreman @ $3.25 per day. + 4 Spaders " 2.00 " " + 12 Laborers " 1.75 " " + +Details of the 20-ft. forms are shown on Plate XLIV. The lower 4 ft. of +lagging was built on swinging arms, which could be loosened to allow the +centers to be dropped and moved ahead. The rest of the lagging was built +up in panels 10 ft. long and 1 ft. 4 in. high. The ribs rested on a +longitudinal timber on each side; these were blocked up from the top +step of the duct bench concrete. When the form was set, or when it was +released, it was moved ahead on rollers placed under it. + +The concrete was received at the form in ¾-cu. yd. dumping buckets; +from the flat cars on which they were run, these were hoisted to the +level of the lower platform of the arch form. At this level the concrete +was dumped on a traveling car or stage, and moved in that to the point +on the form where it was to be placed. For the lower part of the arch, +the concrete was thrown directly into the form from this traveling +stage, but, for the upper part, it was first thrown on the upper +platform of the arch. The hoisting was done by a small Lidgerwood +compressed-air hoister, and set up on an overhead platform across the +tunnel. The pulley over which the cable from the hoister passed was +attached to the iron lining near one end of the form, and the traveling +stage ran back from the arch form on a trailer, shown on Plate XLIV. +When it was impossible to hang a pulley--owing to the concrete arch +having been built at the point where the trailer stood--an =A=-frame was +built on the trailer, and the pulley was attached to that. + +In laying the lower part of the arch, about 1 ft. of lagging (including +the swinging arms) was first set, the other panels being pulled up +toward the top of the arch. When that was filled, the next panel above +was lowered into place, and the work continued. As the concrete rose +toward the key, it was packed up to a radial surface, so that the arch +would not be unduly weakened if the sides set before the key was placed. +All the time, great care was taken to see that the concrete was +carefully packed into the segments of the metal lining. The quantity of +water used in the concrete was carefully regulated, more being used in +the lower than in the upper parts of the arch. + +In places where there were no reinforcing rods, the width of the +concrete key was the length of the block lagging, namely, 2 ft. Where +there was circumferential reinforcement, the key had to be more than 5 +ft. wide, in order to take the 5-ft. closure rods used in the key. This +naturally increased the time of keying very much. On the places where +the 5-ft. longitudinal laggings were used, it was impossible to fill the +flanges of the metal lining much higher than their undersides. + +As the concrete used in the key had to be much drier than that used +elsewhere, it was not easy to get a good surface. This trouble was +overcome by putting a thin layer of mortar on the laggings just before +the concrete was put in. + +The overhead conductor pockets were a great hindrance to the placing of +the key concrete, especially where the iron was below true grade. +Whenever an especially troublesome one was met, a special grout pipe was +put in to fill up unavoidable holes by grouting after the concrete had +set. All the circumferential reinforcing rods were bent in the tunnel by +bending them around a curved form of less diameter than the required +bend. This generally left them all right in the middle of their length, +but with their end portions too straight; in such cases the ends were +bent again. All rods were compared with a template before being passed +for use. + +The arch forms were left up for 48 hours after keying was finished. +Levels taken after striking the forms showed that no appreciable +settlement occurred. An average gang for a 20-ft. length of arch was: + + 1 Foreman @ $3.25 per shift. + 2 Spaders " 2.00 " " + 10 Laborers " 1.75 " " + +Table 30 shows the progress attained under various conditions. + +Whenever the face of the bench concrete was constructed before the arch, +the latter was built in two separate portions, that is, the bottom 5 +ft., or "haunches" of the arch, as they were termed, were built on each +side and the rest of the arch later. This involved the use of two +separate sets of forms, namely, for the haunch and for the arch. Not +very much arch was built in this way, and, as the methods were in +principle precisely the same as those used when all the arch was built +in one operation, no detailed description is needed. + +No provision was made in the contract for grouting the concrete arch, +but it soon became evident that by ordinary methods the top part of the +concrete could not be packed solid against the iron segments, especially +in the keys. As it was imperative to have the arch perfectly solid, it +was determined to fill these unavoidable gaps with a 1:1 Portland cement +grout, at the same time making every effort to reduce the spaces to a +minimum. This made it necessary to build grout pipes into the concrete +as it was put in. + +The first type of grout pipe arrangement is shown as Type _A_, in Fig. +23. This was used with the longitudinal key laggings; when this method +was found to be no good, and cross-laggings were used, the system shown +as Type _B_, in Fig. 23, was adopted, in which vents were provided to +let out the air during grouting. The expense of these pipes was high, +and the contractor obtained permission to use sheet-iron tubes, which, +however, were found to be unsuitable, so that the screwed pipes were +used again. The contractor next obtained permission to try dispensing +altogether with the vent pipes, and so Type _C_, in Fig. 23 was evolved. +This, of course, was found to be worse than any of the other systems, as +the imprisoned air made it impossible to force grout in. Several other +modifications were made, and are shown in Fig. 23. + +It was then decided to devise as perfect a system as possible, without +allowing the question of cost to be the ruling factor, and to use that +system throughout. In this system, shown as Type _S_, in Fig. 23, most +of the vent pipes were contained in the concrete, and their size was +independent of the thickness of the arch, so that they were easily +fixed in position and not subject to disturbance while placing the +concrete. This system was used for about 80% of the total length of the +tunnel, and proved entirely satisfactory. The machine used for grouting +was the same as that used for grouting outside the metal lining. + +TABLE 30.--AVERAGE TIME TAKEN FOR VARIOUS OPERATIONS CONNECTED WITH +BUILDING CONCRETE ARCHES IN SUBAQUEOUS TUNNELS. + + ==========+=============+========+================+=========+=========+ + Average |Type of |Length |Time, in hours, |Time, |Time, | + time |reinforcement|of |moving and |in hours,|in hours,| + in hours, | |section,|erecting forms. |placing |placing | + form stood| |in | |concrete |concrete | + after | |feet. | |in arch. |in key. | + filing. | | | | | | + | | | | | | + ----------+-------------+--------+----------------+---------+---------+ + 70 | { A | } 50 | 20 | 15 | 15.40 | + | {day work | } | ______/\______ | | | + | | |/ \| | | + | { A | } |Moving Erecting| | | + | {day work | } 20 | 2 3 | 8.30 | 2.40 | + | | | | | | + 53 | { B | } | | | | + | {day work | } 20 | 2 3 | 10.40 | 11.20 | + | | | | | | + 58 | { C | } | | | | + | {day work | } 20 | 2 3 | 11.00 | 7.20 | + | | | | | | + 58 | { D | } | | | | + | {day work | } 20 | 2 3 | 9.30 | 4.35 | + | | | | | | + 53 | { D | } | | | | + | {day work | } 20 | 2 3 | 6.15 | 2.05 | + | | | | | | + 53 | {Sub-Type | } 20 | 2 3 | 6.00 | 3.00 | + | No. 1 | } | | | | + | piece work | } | | | | + ==========+=============+========+================+=========+=========+ + + ==========+=========+===========+===========+============ + Average |Time, |Total Time |Total time |Remarks. + time |in hours,|in hours, |in hours, | + in hours, |placing |for moving,|per linear | + form stood|concrete |erecting, |foot, | + after |in key |and filling|for moving,| + filing. |and arch | |erecting, | + | | |and filling| + ----------+---------+-----------+-----------+------------ + 70 | 30.40 | 50.40 | 1.01 | + | | | | + | | | | + | | | | + | 11.10 | 16.10 | 0.50 | + | | | | + 53 | | | |Includes + | 22.10 | 27.00 | 1.35 |placing rods + | | | | + 58 | | | | + | 18.20 | 23.20 | 1.16 | do. + | | | | + 58 | | | | + | 14.25 | 19.25 | 0.91 | do. + | | | | + 53 | | | | + | 8.20 | 13.20 | 0.05 | do. + | | | | + 53 | 9.00 | 14.00 | 0.70 | do. + | | | | + | | | | + ==========+=========+===========+===========+============ + +[Illustration: FIG. 23.] + +The only compressed air available was the high-pressure supply, at about +90 lb.; a reducing valve, to lower this pressure to 30 lb. was used +between the air line and the grouting machine. This was thought to be +about as high a pressure as the green concrete arch would stand, and, +even as it was, at one point a section about 2 ft. by 1 ft. was blown +out. + +A rough traveling stage resting on the bottom step of the duct bench +concrete was used as a working platform. In the earlier stages of the +work the grouting was carried on in a rather haphazard manner, but, when +the last system of grout and vent pipes was adopted; the work was +undertaken systematically, and was carried out as follows: + +Two 20-ft. lengths of arch were grouted at one time, and, in order to +prevent the grout from flowing along the arch and blocking the pipes in +the next lengths, a bulkhead of plaster was made at the end of every +second length to confine the grout. + +After a section had been grouted, test holes were drilled every 50 ft. +along the crown to see that all the voids were filled; if not, holes +were drilled in the arch, both for grouting and for vents, and the +faulty section was re-grouted. An average of ¾ bbl. of cement and an +equal quantity of sand was used per linear foot of tunnel. The average +amount put in by one machine per shift was 15 bbl., and therefore the +average length of tunnel grouted per machine per shift was 20 ft. The +typical working force was: + + 1 Foreman @ $3.75 per shift + 1 Laborer running grout machine " 2.00 " " + 2 Laborers handling cement and sand. " 1.75 " " + 1 Laborer tending valve and grout pipes " 1.75 " " + +After the grouting was finished, the arches were rubbed over with wire +brushes to take off discoloration, and rough places at the junctions of +adjoining lengths or left by the block laggings were bush-hammered. + +_Face of Bench Concrete._--The form used for this portion of the work is +shown on Plate XLV. It consisted of a central framework traveling on +wheels, and, from the framework, two vertical forms were suspended, one +on each side, and equal in height to the whole height of the bench. +Adjusting screws were fitted at intervals both at top and bottom, and +thus the position of the face forms could be adjusted accurately. The +face forms were built very carefully of 3-in. tongued and grooved yellow +pine, and one 50-ft. form was used for 3,000 ft. of tunnel without +having the face renewed. Great care was taken to set these forms true to +line and grade, as the appearance of the tunnel would have been ruined +by any irregularity. Joints between successive lengths were finished +with a =V=-groove. + +The concrete was received at the form in dumping buckets; these were +hoisted to the top of the form by a Lidgerwood hoister fixed to a +trailer. The concrete was placed in the form by shoveling it from the +traveling stage down chutes fitted to its side. The quantity of water to +be used in the mixture needed careful regulation. The first few batches +in the bottom had to be very wet, and were made with less stone than the +upper portion, in order that the concrete would pack solidly around the +niche box forms and other awkward corners. + +The forms for the ladders and refuge niches were fastened to the face of +the bench forms by bolts which could be loosened before the main form +was moved ahead, and in this way the ladder and niche forms were left in +position for some time after the main form was removed. + +At first the forms were kept in place for 36 hours after finishing a +length, but, after a little experience, 24 hours was found to be enough. +In the summer, when the rise of temperature quickened the set, the time +was brought down to 18 hours. The average time taken for a 50-ft. length +was: + + Laying concrete 4½ hours. + Interval for setting 18 " + Moving forms ahead and resetting 5 " + ------- + Total 27½ hours. + +The typical working gang was: + +_Laying Concrete._ + + 1 Foreman @ $3.25 per shift. + 2 Spaders " 2.00 " " + 8 Laborers " 1.75 " " + +_Moving and Setting Forms._ + + 1 Foreman @ $4.00 per shift. + 10 Laborers " 1.75 " " + +After the forms were removed, any rough places at the lower edge, where +the concrete joins the "lip," were bush-hammered; no other cleaning work +was done. + +_Duct Laying and Rodding._--The design and location of the ducts have +already been described. It will have been seen that the duct-bench +concrete was laid in steps, on which the ducts were laid, hence the +maintenance of the grade and line in the ducts was an easy matter. The +only complication was the expanded metal bonds, which were bent up out +of the way of the arch forms and straightened out again after the arch +forms had passed. The materials, such as ducts, sand, and cement, were +brought into the tunnel by the regular transportation gang. The mortar +was mixed in a wooden trough about 10 ft. long, 2 ft. 6 in. wide and 8 +in. deep. + +After the single-way ducts had been laid, all the joints were plastered +with mortar, in order to prevent any foreign substance from entering the +ducts. This was not necessary with the multiple duct, as the joints were +wrapped with cotton duck. The ducts were laid on a laying mandrel, and, +as soon as possible after the concrete was laid around a set of ducts, +they were "rodded" with a rodding mandrel. Not many obstructions were +met, and these were usually some stray laying mandrel which had been +left in by mistake, or collections of mortar where the plastering of the +single-way joints had been defective. + +In the 657,000 duct ft. of conduit in the river tunnels only eight +serious obstructions were met. That the work was of exceptionally high +quality is shown by the fact that a heavy 3-in. lead cable has been +passed through from manhole to manhole (450 ft.) in 6 min., and the +company, engaged to lay the cables in these ducts, broke all its +previous records for laying, not only for tunnel work, but also in the +open. + +Fig. 1, Plate XXXV, shows a collection of the tools and arrangements +used in laying and rodding ducts. The typical working force was: + +_Laying Multiple Ducts._ + + 1 Foreman @ $3.50 per shift. + 9 Laborers " 1.75 " " + +_Laying Single-Way Ducts._ + + 1 Foreman @ $3.50 per shift. + 8 Laborers " 1.75 " " + +_Rodding Multiple Ducts._ + + 1 Foreman @ $3.50 per shift. + 5 Laborers " 1.75 " " + +_Rodding Single-Way Ducts._ + + 1 Foreman @ $3.50 per shift. + 5 Laborers " 1.75 " " + +The average progress per 10-hour shift with such gangs was: + + Laying multiple ducts 4,000 duct ft. + Laying single-way ducts 1,745 " " + Rodding multiple ducts 4,040 " " + Rodding single-way ducts 2,532 " " + +No detailed description need be given of the concreting of the +cross-passages, pump chambers, sumps, and other small details, the +design of which has been previously shown. The concrete was finished on +June 1st, 1909. + +_Period No. 6._--_Final Cleaning Up._--_June, 1909, to November, +1909._--As soon as all the concrete was finished, the work of cleaning +up the invert was begun. A large quantity of débris littered the +tunnels, and it was economical to remove it as quickly as possible. The +remaining forms were first removed, and hoisting engines, supported on +cross-timber laid across the benches, were set up in the middle of the +tunnel at about 500-ft. intervals. + +Work was carried on day and night, and about 169 ft. of single tunnel +was cleared per 10-hour shift. Work was begun on May 28th, and finished +on July 15th, 1909. For part of the time it was carried on at two points +in each tunnel, working toward the two shafts, but when the work in the +Weehawken Shaft, which was being done at the same time, blocked egress +from that point, all material was sent out by the Manhattan Shaft. + +The total quantity of material removed was 5,350 cu. yd., or about 0.44 +cu. yd. per lin. ft. of tunnel. The average force per shift was: + +_In Tunnel._ + + 3 Foremen @ $3.25 per shift + 1 Hoist engineer " 3.00 " " + 1 Signalman " 2.00 " " + 38 Laborers " 1.75 " " + +_On the Surface._ + + 1 Foreman @ $3.25 per shift + 1 Hoist engineer " 3.00 " " + 1 Signalman " 2.00 " " + 12 Laborers " 1.75 " " + +After the cleaning out had been done, the contractor's main work was +finished. However, quite a considerable force was employed, up to +November, 1909, in doing various incidental jobs, such as the +installation of permanent ventilation conduits and nozzles at the +intercepting arch near the Manhattan Shaft, the erection of a head-house +over the Manhattan Shaft, and collecting and putting in order all the +miscellaneous portable plant, which was either sold or returned to +store, sorting all waste materials, such as lumber, piping, and scraps +of all kinds, and, in general, restoring the sites of the working yards +to their original condition. + + +Concrete Mixing. + +The plant used in mixing the concrete for the land tunnels was pulled +down and re-erected before the concrete work in the river tunnels was +begun. At the New York shaft two new bins for sand and stone were built, +bringing the total capacity up to 950 cu. yd. Two No. 6 Ransome mixers, +driven electrically by 30-h.p. General Electric motors, using current +from the contractor's generators, were set up on a special platform in +the intercepting arch. + +At Manhattan the sand and stone were received from the bins in chutes at +a small hopper built on the permanent upper platform of the intercepting +arch. Bottom-dumping cars, divided by a partition into two portions, +arranged to hold the proper quantities of sand and stone for a 4-bag +batch of concrete, were run on a track on this upper platform, filled +with the proper quantities of sand and stone, and then run back and +dumped into the hoppers of the mixer. After mixing, the batch was run +down chutes into the tunnel cars standing on the track below. The water +was brought in pipes from the public supply. It was measured in barrels +by a graduated scale within the barrels. The water was not put into the +mixer until the sand and stone had all run out of the mixer hopper. The +mixture was revolved for about 1½ min., or about 20 complete +revolutions. + +At Weehawken Shaft the mixing plant was entirely rebuilt. Four large +bins, two for sand and two for stone, were built in the shaft. Together, +they held 430 cu. yd. of stone and 400 cu. yd. of sand. The sand and +stone were dumped directly into the bins from the cars on the trestle +which ran from the wharf to the shaft. The materials were run through +chutes directly from the bins to the hoppers of the mixers, where they +were measured. Two No. 6 Ransome mixers, electrically driven, were used +here, as at New York, and, as there, the water was led into measuring +tanks before being let into the mixer. + +The quantity of water used in the various parts of the concrete +cross-section, for a 4-bag batch consisting of 1 bbl. (380 lb.) of +cement, 8.75 cu. ft. of sand, and 17.5 cu. ft. of stone, is given in +Table 31. + +TABLE 31.--QUANTITY OF WATER PER 4-BAG BATCH OF CONCRETE, IN U.S. +GALLONS. + + ==========================+==========+==========+========== + Portion of cross-section. | Maximum. | Minimum. | Average. + --------------------------+----------+----------+---------- + Invert | 40 | 20 | 26 + Duct bench | 36 | 21 | 27 + Arch (excluding key) | 37 | 19 | 25 + Key of arch | 27 | 15 | 20 + Face of bench | 31 | 22 | 27 + ==========================+==========+==========+========== + +The maximum quantities were used when the stone was dry and contained +more than the usual proportion of fine material, the minimum quantity +when the sand was wet after rain. + +The resulting volumes of one batch, for various kinds of stone, are +given in Table 32. + +TABLE 32.--VOLUME OF CONCRETE PER BATCH, WITH VARIOUS KINDS OF STONE. + + ========+===========+================+===========+==================| + | | Resulting | | + | DESCRIPTION OF STONE. |volume per | | + Mixture.|-----------+----------------| barrel of | Remarks. | + | | |cement, in | | + | Passed | Retained on | cubic | | + | screen. | screen. | yards. | | + --------+-----------+----------------+-----------+------------------| + 1:2½:5 | 1½-in. | 3/8-in. | 0.815 | Measured in air | + 1:2½:5 | 2½-in. |Run of crusher. | 0.827 | " " " | + 1:2½:5 | -- |General average.| 0.808[D]|Measured from plan| + 1:2½:5 | 2-in. | 1½-in. | 0.768[E]| " " " | + ========+===========+================+===========+==================| + +[D] Average for whole of River Tunnel section. + +[E] Average from 7,400 cu. yd. in Land Tunnel section. + +The sand used was practically the same for the whole of the river tunnel +section, and was supposed to be equal to "Cow Bay" sand. The result of +the mechanical analysis of the sand is shown on Plate XLVI. The stone +was all trap rock. For the early part of the work it consisted of stone +which would pass a 2-in. ring and be retained on a 1½-in. ring, in +fact, the same as used for the land tunnels. This was found to be too +coarse, and for a time it was mixed with an equal quantity of fine +gravel or fine crushed stone. As soon as it could be arranged, +run-of-crusher stone was used, everything larger than 2½ in. being +excluded. About three-quarters of the river tunnel concrete was put in +with run-of-crusher stone. The force was: + +_At Manhattan._ + + 1 Foreman @ $3.00 per shift + 4 Men on sand and stone cars " 1.75 " " + 4 Men handling cement " 1.75 " " + 2 Men dumping mixers " 1.75 " " + +_At Weehawken._ + + 1 Foreman @ $3.00 per shift + 2 Men hauling cement " 1.75 " " + 2 Men dumping mixers " 1.75 " " + +The average quantity of concrete mixed per 10-hour shift was about 117 +batches, or about 90 cu. yd. The maximum output of one of the mixers was +about 168 batches, or 129 cu. yd. per 10-hour shift. + + +Transportation. + +_Surface Transportation._--At Manhattan the stone and sand were received +in scows at the wharf on the river front. For the first part of the +work, the wharf at 32d Street and North River was used, and while that +was in use the material was unloaded from the scows into scale-boxes by +a grab-bucket running on an overhead cable, and then teamed to the +shaft. For the latter part of the work, the wharf used was at 38th +Street and North River, where facilities for unloading were given to the +contractor by the Pennsylvania Railroad Company which was the permanent +lessee of the piers. The material was unloaded into scale-boxes by a +grab-bucket operated by a derrick, and teamed to the shaft. When the +scale-boxes arrived at the shaft they were lifted from the trucks by +derricks and dumped into the bins. + +At Weehawken all the stone and sand, with the exception of the stone +crushed on the work, was received by water at the North slip. Here it +was unloaded by a 2-cu. yd. grab-bucket and dumped into 3-cu. yd. +side-tipping cars, which were hauled by a small steam locomotive over +the trestle to the shaft, where they were dumped directly into the bins. + +Before beginning the concrete lining, the 2-ft. gauge railway, which had +been used for the surface transportation during the driving of the +iron-lined tunnels, was taken up and replaced by a 3-ft. gauge track +consisting largely of 30-lb. rails. The cars were 3-cu. yd. +side-dumping, with automatic swinging sides. Two steam locomotives which +were being stored at Weehawken (part of the plant from another +contract), were used for hauling the cars in place of the electric ones +used with the 2-ft. gauge railway. + +_Tunnel Transport._--The track used in the tunnel was of 2-ft. gauge, +laid with the 20-lb. rails previously used in driving the iron-lined +tunnels. The mining cars (previously mentioned in describing the driving +of the iron-lined tunnels) were used for transporting the invert +concrete, although, for most of the work, dumping buckets carried on +flat cars were used. Several haulage systems were considered for this +work, but not one of them was thought to be flexible enough to be used +with the constantly changing conditions, and it was eventually decided +to move all the cars by hand, because, practically all the work being +down grade, the full cars could be run down by gravity and the empty +ones pushed back by hand. Two men were allotted to each car, and were +able to keep the traffic moving in a manner that would have been perhaps +impossible with any system of mechanical haulage. This system was +apparently justified by the results, for the whole cost of the tunnel +transport, over an average haul of about 2,000 ft., was only about 50 +cents per cu. yd., which will be found to compare favorably with +mechanical haulage on similar work elsewhere, provided full allowance is +made for the use of the plant and power. + +_Force Employed._--The average force employed on transport, both on the +surface and in the tunnel, is shown in Table 33. + + +Costs. + +During the work, careful records of the actual cost to the contractor of +carrying out this work were kept by the Company's forces; these costs +include all direct charges, such as labor and materials, and all +indirect charges such as head office, plant depreciation, insurance, +etc., but do not include the cost of any financing, of which the Company +had no information. + +TABLE 33.--AVERAGE FORCE PER SHIFT FOR TRANSPORTATION IN TWO TUNNELS. + + ========+==================+=====+==========+============+===========+ + Location|Grade |Rate | WORK IN PROGRESS | + | | |----------+------------+-----------+ + | | | Two |Two arches, |Four arches| + | | | inverts |two inverts,| and one | + | | | and two |and two duct| face of | + | | | duct | benches | bench | + | | | benches | | | + --------+------------------+-----+----------+------------+-----------+ + {|Foreman |$3.00| 2 | 2 | 2 | + Tunnel {|Laborer | 1.75| 24 | 28 | 70 | + {|Switchmen | 2.00| | 2 | 2 | + {|Hoisting engineers| 3.00| 2 | 4 | 5 | + {|Foreman | 3.00| 1 | 1 | 2 | + Surface{|Laborers | 1.75| 8 | 8 | 15 | + {|Teams | 6.50| 1 | 1 | 2 | + ========+==================+=====+==========+============+===========+ + + +Field Engineering Staff. + +The field staff may be considered as divisible into five main divisions: + + (_A_).--Construction, including alignment, + + (_B_).--Cost records, + + (_C_).--Testing of cement and other materials of construction, + + (_D_).--Photography, + + (_E_).--Despatch-boat service. + +(_A_).--_Construction_ (_Inspection and Alignment_) _Staff._--A +comparatively large staff was maintained by the Company, and to this two +causes contributed. In the first place, the contractor maintained no +field engineering staff, because, early in the proceedings, it was +arranged that the Company would carry out all this work, and thus avoid +the overlapping, confusion, and lack of definite responsibility which +often ensues when two engineering forces are working over the same +ground. Even had the contractor maintained an engineering force, it +would have been necessary for the Company to check most of the +contractor's work. + +In the second place, this work gave rise to a number of special surveys, +tests, borings, and observations of various kinds, most of which were +kept up as a part of the regular routine work, and this necessitated a +staff. Also, for a whole year, active progressive work was at a +standstill while the pile tests were going on. + +(_B_).--_Cost Records Staff._--A distinct feature was made of keeping as +accurately as possible detailed records of the actual cost to the +contractor of carrying out the work. A small staff of clerks, retained +solely for this purpose, tabulated and recorded the information +furnished by the members of the construction staff. About $12,000, +altogether, was spent in salaries in this department, and it may be +considered an extremely wise investment, for, not only is the +information thus obtained of great value and interest in itself, but it +also puts the Company in an excellent position should any claim or +discussion arise with the contractor. + +(_C_).--_Cement-Testing Department._--As the Company furnished the +cement to the contractor, it became incumbent to make careful tests of +the quality. A cement-testing laboratory was established at the +Manhattan Shaft offices, under the charge of a cement inspector who was +furnished with assistants for sampling, shipping, and testing cement. +All materials used on the work, such as bricks, sand, stone, +water-proofing, etc., were tested here, with the exception of metals, +which were under the charge of a metal inspector reporting directly to +the head office. This department cost about $10,000 for salaries and +$3,000 for apparatus and supplies, or about $13,000, in all. + +There were 800,000 bbl. of cement tested, and samples from 2,100,000 +brick. A large amount of useful information has resulted from the work +of this laboratory. + +(_D_).--_Photography._--It was desired to keep a complete photographic +record of the progress of the work, and therefore a photographer was +appointed, with office room at the Manhattan Shaft. The photographer +took all the progress photographs on the work of the North River +Division, made photographic reductions of all drawings and plans, made +lantern slides of all negatives of a more important nature, and, in +addition, during the period of compressed air, analyzed the samples of +compressed air, brought into the office for the purpose, for the amount +of CO_{2} present. About $8,000 was spent on this department. + +(_E_).--_Despatch-Boat Service._--To provide access to the New Jersey +side, a despatch boat was purchased. This boat was at first (June, 1904) +chartered, and in May, 1905, was bought outright, and ran on regular +schedules, day and night. It continued in the service until April, +1909, when it was given up, as the tunnels were so far completed that +they provided easy access to New Jersey. The cost of the boat +(second-hand) was about $3,000. It was then thoroughly overhauled and +the cabin remodeled. The monthly cost, when working a 12-hour shift, was +$270 for manning, $65 for supplies, and $64 for coal. On two 12-hour +shifts, the monthly cost was $533 for manning, $100 for supplies, and +$96 for coal. About 100,000 passengers were carried during the boat's +period of service, and the total cost was about $37,500. + +For the major part of the period embraced by this paper, B. H. M. +Hewett, M. Am. Soc. C. E., served as General Resident Engineer, in +charge of the Field Work as a whole. + +W. L. Brown, M. Am. Soc. C. E., was at first Resident Engineer of the +work constructed from the Manhattan Shaft, while H. F. D. Burke, M. Am. +Soc. C. E., was Resident Engineer of the work constructed from the +Weehawken Shaft. After the meeting of the shields, Mr. Burke left to +take up another appointment, and from that time Mr. Brown acted as +Resident Engineer. + +It may be said, without reflecting in any way on the manufacturers, that +the high standard of all the metal materials also testified to the +efficient inspection conducted under the direction of Mr. J. C. +Naegeley. + +It is impossible to close this brief account of these tunnels without +recording the invaluable services at all times rendered by the members +of the Company's field staff. Where all worked with one common aim it +might seem invidious to single out names, but special credit is due to +the following Assistant Engineers: Messrs. H. E. Boardman, Assoc. M. Am. +Soc. C. E., W. H. Lyon, H. U. Hitchcock, E. R. Peckens, H. J. Wild, +Assoc. M. Am. Soc. C. E., J. F. Sullivan, Assoc. M. Am. Soc. C. E., and +R. T. Robinson, Assoc. M. Am. Soc. C. E. Mr. C. E. Price was in charge +of the cement tests throughout the entire period, and brought to his +work not only ability but enthusiasm. Mr. H. D. Bastow was in charge of +the photographic work, and Mr. A. L. Heyer of the cost account records, +in which he was ably seconded by Mr. A. P. Gehling, who, after Mr. +Heyer's departure, finished the records and brought them into their +final shape. The organization of the Company's field engineering staff +is shown graphically by Fig. 24. + +FIELD ORGANIZATION OF THE O'ROURKE ENGINEERING CONSTRUCTION COMPANY FOR +THE BUILDING OF THE PENNSYLVANIA RAILROAD TUNNELS INTO NEW YORK +CITY--NORTH RIVER DIVISION. SECTIONS GY EAST, GY WEST SUPPLEMENTARY, GY +WEST, AND CO. + + + GENERAL SUPERINTENDENT. + | + +------------------------+-------+--+ + | | | + (General, Surface and Office) (Excavation | + ---------------+------------- of Land | + | Tunnels) | + ASSISTANT GENERAL SUPERINTENDENT | | + | GENERAL | + | ROCK SUPT | + +------------+------------+ | | + | | | Tunnel | + FIELD SURFACE DESPATCH Supts | + OFFICE BOAT Tunnel | + Foreman | + Civil Head Captain Foremen | + Engineer Carpenter Engineer Timbermen | + Inspectors Foreman Deck Hands Timbermen | + Bookkeepers Carpenter Timbermen's | + Paymaster Carpenters Helpers | + Head Carpenters' Foremen | + Storekeeper Helpers Drillers | + Storekeepers Blacksmiths Drillers | + Timekeepers Blacksmiths' Foremen | + Telephone Helpers Muckers | + Operators Foreman Pipe Fitters | + Office Boys Laborers Pipe Fitters' | + Messengers Laborers Helpers | + Janitors Disposal Electricians | + Trimmers Hoist | + Teamsters Engineers | + Signalmen | + Muckers | + Nippers | + Water Boys | + | + | + -------------+--------+-------------------------+--------+----------+ + | | | | + (Shield Tunnel Driving) (Masonry (Power (Medical + | Lining-Rock Plant) Supervision) + GENERAL TUNNEL SUPERINTENDENT and River | | + | Tunnels) MASTER CHIEF MED + ASSISTANT SUPERINTENDENTS | MECHANIC OFFICER + | | | | | | | + +--------+------------+---------+ | Foreman | + EXCAVATION | | GENERAL | Electrician | + | IRON LINING CAULKING AND | | Electricians | + General | GRUMMETING | | Engineers | + Foremen Foremen | Pipefitters | Foreman Resident + Foremen Erector Foremen Pipefitters' | Machinist Doctor + Drillers Runners Caulkers Helpers | Machinists + Drillers Ironmen Grummeters Electricians | Machinists' + Powdermen Boltmen Electricians'| Helpers + Foremen Helpers | Firemen + Timbermen Trackmen | Oilers + Timbermen Lockmen | Pumpmen + Foremen Transport | Hoist Engineers + Muckers Foreman | Signalmen + Muckers Transport | + Shieldmen Laborers | + Laborers Watchmen | + Nippers | + Water Boys | + GENERAL CONCRETE SUPERINTENDENT + | + TUNNEL SUPERINTENDENTS + | + +-----------+------------+----------------++-----------+ + | | | | | + CONCRETE BRICKWORK DUCTS WATER-PROOFING GENERAL + + Foremen Foremen Foremen Foremen Pipefitters + Carpenters Bricklayers Duct-layers Waterproofers Pipefitters' + Carpenters' Bricklayers' Helpers + Helpers Laborers Electricians + Mixer Carpenters Electricians' + Foremen Carpenters' Helpers + Mixer Helpers Transport + Laborers Foremen + Concrete Transport + Laborers Laborers + Watchmen + + FIG. 24. + +_Contractor's Organization._--The contracting firm which did the work +described in this paper was the O'Rourke Engineering Construction +Company, of New York City. The President of this Company was John F. +O'Rourke, M. Am. Soc. C. E., the Vice-President was F. J. Gubelman, +Assoc. M. Am. Soc. C. E. The General Superintendent was Mr. George B. +Fry, assisted by J. F. Sullivan, Assoc. M. Am. Soc. C. E. The duties of +General Tunnel Superintendent fell to Mr. Patrick Fitzgerald. The +generally pleasant relations existing between the Company and the +contractor's forces did much to facilitate its execution. + +The organization of the Contractor's field staff is shown on Fig. 25. + +PENNSYLVANIA TUNNEL AND TERMINAL RAILROAD COMPANY. NORTH RIVER DIVISION. + +SECTIONS GY EAST, GY WEST SUPPLEMENTARY, GY WEST, GJ, AND I, _I. E._, +FROM 10TH AVENUE, MANHATTAN, TO THE WEEHAWKEN SHAFT, FIELD ENGINEERING +STAFF ORGANIZATION. + + GENERAL RESIDENT ENGINEER + | + +-----------------+------------+------------+---------+----+ + | | | | | | + (Material Testing) (Photography) | (Cost Records) |(Office) + Cement Inspector Photographer | Recording Clerk | Clerks + Asst Cement | Asst Recording |Messengers + Inspectors | Clerks | + (Construction) | + | (Despatch Boat) + +----------------+ Captain + | Engineers + RESIDENT ENGINEERS Deckhands + (Two during driving of Shield-driven Messengers + Tunnels, and one subsequently.) + | + +---------------------+---+------------------+ + | | | + (Inspection) (Alignment) (Office) + Assistant Engineers Assistant Engineers Draftsmen + Chief Tunnel Chiefs of Parties Field Office + Inspector Instrumentmen Clerks + Tunnel Inspectors Rodmen Cement + Surface Inspectors Chainmen Warehousemen + Clerks Laborers Janitors + + FIG. 25 + +In conclusion, the writers cannot forego the pleasure of expressing +their deep obligation to Samuel Rea, M. Am. Soc. C. E., as representing +the Management of the Company, to the Chief Engineer, Charles M. Jacobs, +M. Am. Soc. C. E., and to James Forgie, M. Am. Soc. C. E., Chief +Assistant Engineer, for their permission to write this paper, and also +to all the members of the field office staff for their great and +unfailing assistance in its preparation. + + + + + +End of the Project Gutenberg EBook of Transactions of the American Society +of Civil Engineers, Vol. LXVIII, Sept. 1910, by B. H. M. Hewett and W. L. Brown + +*** END OF THE PROJECT GUTENBERG EBOOK 42149 *** |