The Raymond concrete pile (Fig. 57) is constructed in place. A collapsible steel pile-core is encased in a thin, closely-fitting, sheet-steel shell. The core and shell are driven to the required depth by means of a pile-driver. The core is so constructed that when the driving is finished, it is collapsed and withdrawn, leaving the shell in the ground, which acts as a mould for the concrete. When the core is withdrawn, the shell is filled with concrete, which is tamped during the filling process. These piles are usually 18 inches to 20 inches in diameter at the top, and 6 inches to is usually No. 20 gauge. When it is desirable to reinforce these piles, the bars are inserted in the shell after the core has been withdrawn and before the concrete is placed.

8 inches at the point. When it is desirable, the pile can be made larger at the small end. The sheet steel used for these piles

Fig. 55. Section of Corrugated Pile.

Fig. 55. Section of Corrugated Pile.

Fig. 56. Cushion Head for Driving Piles.

Fig. 56. Cushion Head for Driving Piles.