In excavating for the foundation of a 16-story building at 14th Street and 5th Avenue, New York, a pocket of quicksand was discovered with a depth of about 14 feet below the bottom of the general excavation. A wall column of the building to be constructed was located at this point, with its center only 15 inches from the party line. The estimated load to be supported by this column was about 500 tons. It was finally decided to adopt steel piles which would afford the required carrying capacity in a small, compact cluster, and would transfer the load as well as the other foundations to the solid rock. These piles, 5 in number, were driven very close to an existing wall and without endangering it. Each pile was about 15 feet long, and was made with an outer shell consisting of a steel pipe 3/8 inch thick and 12 inches inside diameter,filled with Portland cement concrete, reinforced with four vertical steel bars 2 inches in diameter. This gave a total cross-sectional area of 27.2 square inches of steel, with an allowed load of 0,000 pounds per square inch, and 100.5 square inches of concrete on which a unit-stress of 500 pounds was allowed. This utilizes the bearing strength of the external shell, and enables the concrete filling to be loaded to the maximum permitted by the New York Building Laws. The tubes and bars have an even bearing on hard bed-rock, to which the former were sunk by the use of a special air hammer and an inside hydraulic jet. The upper ends of the steel tubes and reinforcing bars were cut off after the piles were driven. The work was done with care, and a direct contact was secured between them and the finished lower surfaces of the cast-iron caps, without the intervention of steel shims.*

Fig. 57. Raymond Concrete Pile.

Fig. 57. Raymond Concrete Pile.

Fig. 58. Standard Simplex Concrete Piles.

Fig. 58. Standard Simplex Concrete Piles.