Steel piles as foundations in constructions

A steel pile can be a coiled H section or a steel pipe known as a tubular pile. Due to their small cross section, steel piles can often be driven into dense soils where a solid cross section pile would be difficult to drive through dense soil. However, one point must be considered when driving long structural forms: the possibility of the pile tip striking a large rock below the surface. There have been many cases where long steel boulders have been deflected by large boulders below the surface and, as a result of continued driving, the tip of the pile has returned to the ground surface. This, of course, makes it necessary to extract the pile and determine the boundaries of the rock before proceeding.

Because steel piles develop their load resistance primarily in friction, they are generally driven in groups. Once each pile develops a certain required load resistance, the top is cut to a predetermined elevation. The group is then covered with a pile cap, which helps distribute the supported load evenly to all piles in the group.

Tubular piles range in diameter from 8 to 72 inches (200 to 1,800 mm). They can be driven from the top, using a drop or mechanical hammer, or from the bottom, using a hammer dropped onto a concrete plug. The pipe is usually filled with concrete, which means that if the pipe is driven with open ends, the soil must be removed from the inside by a stream of water.