This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
The different methods for producing the Simplex pile cover the two general classifications of concrete piles - namely, those moulded in place, and those moulded above ground and driven with a pile-driver. Fig. 58 shows the standard methods of producing the Simplex pile. In Fig. 58, A shows a cast-iron point which has been driven and imbedded in the ground, the concrete deposited, and the form partially withdrawn; while B shows the alligator point driving form. The only difference between the two forms shown in this figure, is that the alligator point is withdrawn and the cast-iron point remains in the ground. The concrete in either type is compacted by its own weight. As the form is removed, the concrete comes in contact with the soil and is bonded with it. A danger in using this type of pile is that, if a stream of water is encountered, the cement may be washed out of the concrete before it has a chance to set.
A shell pile and a moulded and driven pile are also produced by the same company which manufactures the Simplex, and are recommended for use under certain conditions. Any of these types of piles can be reinforced with steel. This company has driven piles 20 inches in diameter and 75 feet long.