Numerical analysis of unconnected piled raft with cushion

Abstract The analysis of piled raft foundations has improved over the last few decades to account for the combined contribution of raft and piles to provide a more efficient system. Unconnected piled raft foundation (UCPRF) is an economical and efficient system where the piles are separated from the raft by a structural fill cushion. The cushion acts to redistribute the load between raft and piles. In this study, ABAQUS finite element analysis software was used to investigate the load sharing capacity of the system. The effects of cushion, piles number, diameter, and length as well as raft thickness in reducing settlement were investigated. The study showed that UCPRF provides an economical alternative for a connected piled raft foundation subject to vertical axial loads. In the unconnected system, plain concrete piles are adequate, without the need of reinforcement, where their basic function is to strengthen the top and reduce the maximum settlements.