Seismic response of disconnected piled raft foundation during a strong earthquake based on dynamic centrifuge tests

To understand the seismic performance of a disconnected piled raft (DPR) foundation during strong earthquakes, dynamic centrifuge tests were conducted on a soil–foundation–superstructure system. A residual bending moment occurred in the piles of the DPR during a strong earthquake. The residual lateral displacement at the pile heads was estimated to be 30% of the pile diameter, caused by the cyclic one-sided lateral load from the overturning moment. The residual displacement and bending moment may constitute vulnerabilities of DPRs during strong earthquakes. The sum of the maximum compressive axial loads of the conventional pile foundations (PF) was 1.8 times the weight of the structure. The high axial load in the PF resulted from the piles in the back and middle rows bearing tension forces. The maximum compressive axial load of the piles in the DPR was 55% of that in the PF. The DPR piles did not bear tensile loads. Therefore, when the raft was uplifted, the sum of the compressive axial loads on the front piles of the DPR did not exceed the weight of the structure.