Benjamin Franklin Cresson

“ The elevator derricks at Tenth Avenue were very efficient, and each could take care of the material from four derricks at the bottom, hoisting 250 cu. yd. per shift a height of 60 ft.
Concrete Retaining and Face Walls.—It was essential to have the greatest space possible at the bottom of the excavation, and, inasmuch as the yard was to be left open, it was necessary to provide some facing for the rock on the sides in order to prevent disintegration, due to exposure, and give a finished appearance to the work. ”

“ Earth Excavation.—Practically all the earth excavation, amounting to about 57,000 cu, yd., was done with steam shovels. The average quantity of earth excavated by a steam shovel per 10-hour shift was 180 cu. yd. This material was loaded on side-dump cars and taken to the disposal pier where it was dumped through chutes to the decks of scows. Inasmuch as the quantity of earth excavation was small, as compared with the rock, the earth was used principally for the first layer on the scows for padding, so that small stones might be dumped through the chutes without injuring the decks. ”

“ The prices quoted for excavation included placing the material on scows supplied by the Railroad Company at the pier at the foot of West 32d Street, on the North River; there was a clause in the contract, however, by which the contractor could be required to make complete disposal of all excavated material at an additional unit price, and this clause was enforced on January 1st, 1909, when about 94% of the excavation had been done. ”

“ The average daily traffic over the Ninth Avenue Elevated Railway was 90,000 passengers, and, during the progress of the excavation and underpinning, about 100,000,000 passengers were carried over that structure. ”

“ Supports for Surface Railway Structure.—A uniform load of 3,000 lb. per lin. ft. of single track, with the weight of a car at 39,000 lb., was assumed. Several feet of earth, between the structure and the rock, were mined out, and the structure was supported on I-beams and posts, and ultimately on the transverse girders by using timber bents under the I-beams, as shown on Fig. 3. ”

“ The total excavation was 521,000 cu. yd., of which 87% was solid rock.
The average drill performance was about 33 lin. ft. per 8-hour shift.
The average number of cubic yards of excavation per drill shift was 13.9.
The average number of feet of drilling per cubic yard of excavation was about 2.4.
The average excavation per pound of dynamite was 2.2 cu. yd.
The average amount of excavation per derrick shift of ten hours, 87% of the excavation being rock, was 50 cu. yd.
The average derrick force per shift, including only foreman and laborers, was 13 men. ”

“ The house-wrecking was done by well-known companies under contract with the Railroad Company. These companies took down the buildings and removed all the materials as far as to the level of the adjacent sidewalks. The building materials became the property of the contractors, who usually paid the Railroad Company for the privilege of doing the house-wrecking. ”

“ General Description.—The work involved the excavation of about 375 ft. of the full width of Ninth Avenue to an average depth of about 58 ft., and the construction over this area of a steel viaduct, the deck of which was about 24 ft. below the surface, for the ultimate support of the Ninth Avenue structures.
The following estimated quantities appear in the contract: Excavation of rock, 72,600 cu. yd.; excavation of all materials except rock, 9,300 cu. yd.; concrete (1:3:6) in abutments, etc., 1,680 cu. yd.; timber, 504,000 ft., B.M.; structural steel, 1,320,000 lb., etc. ”

“ The salaries of the engineering staff in the field and the expenses of equipping and maintaining the field office amounted to 2.8% of the cost of the work executed, 2.7% being for engineering salaries alone. ”

“ Plate XLIX, Fig. 3.— TW 88, P.T. & T.R.R. Co. N.R. Div. Terminal Station West. Center line of 32nd St., looking East from Sta. 183+50, showing excavation under Ninth Avenue, permanent concrete piers under Elevated Railway Columns and removal of temporary shoring girders "C". April 8, 09.
Plate XLIX, Fig. 4.— TW 95, P.T. & T.R.R. Co. N.R. Div. Terminal Station West. View under Ninth Avenue looking Southward from 100 feet South of center line, showing underpinning of Ninth Avenue structure taken at sub-grade. ”