Role of Cap Thickness in Pile-Cap Foundation

The thickness of a pile cap is a governing parameter in the design of pile-cap foundations. A thin cap performs as a flexible slab distributing the load on the piles unevenly, which does not accord with the concept of pile foundation design. On the other hand, a thick cap performs as a rigid slab, which will evenly distribute the load on the piles, as well as resisting bending moments and punching shear, however, it may impose additional load on the piles due to its own weight. In view of these differences, there is a need to optimize the thickness of the cap in order to distribute the load evenly on the piles without. In this study, a 3-D numerical model was developed using ABAQUS to simulate a 16-pile cap foundation on soft soil and on dense sand. The cap thickness was examined for a range of 0.5m to 3m. Furthermore, effects of pile spacing, pile diameter, and pile length on the performance of pile-cap foundation were examined.