Uses of enlarged head piles
Enlarged head piles are generally installed on a square or triangular grid pattern for raft foundations, floor slabs and hard-standing areas. They have also been used under road embankments, with or without load transfer platforms or reinforced granular blankets.
The enlarged pile heads reduce the effect of punching shear and a thinner, or more lightly reinforced, slab construction can be used. As enlarged heads become an integral part of the pile construction and are finished at ground level, expensive pile trimming is eliminated. Under-slab waterproofing membranes can be laid directly over pile heads, so expensive cutting and sealing around pile shafts is not necessary.
Enlarged pile heads can be used to enable modular construction, where a building is large enough or its sub-structure is repetitious enough to justify pre-cast ground beams. Enlarged pile heads, finished to an accurate level, permit pre-cast ground beams to be laid directly onto them, eliminating cutting down and shuttered wet concrete work.