ABSTRACT
To study the dynamic soil-foundation-structure interaction, centrifuge shaking table tests on a composite caisson-piles foundation (CCPF) were carried out. A series of 1:50 scaled models were designed to simulate a 2 × 2 pile group connected with caisson. The infinite boundary was simulated by a laminar shear box with rubber film inside to eliminate the reflected wave. The results show that the peak bending moment of pile shaft increases gradually from pile tip to pile head for CCPF in both homogeneous and layered soils. Due to the nonlinearity of the system under strong seismic excitations, the maximum bending moments increase with the input PGA growing yet at reduced rate. Sympathetic vibration may generate in CCPF embedded in layered subgrade consisting of hard soil underlain by soft soil, which will lead to larger acceleration of superstructure and larger bending moment of piles compared with CCPF embedded in homogenous soft soil subgrade.
