Earthquake responses of piles-soil dynamic interaction system for base-isolated structure system based on shaking table tests

Due to the severe earthquake damage of ground structures induced by soil liquefaction, a shaking table test is designed and completed to simulate the seismic performance of the soil-piles-isolated layer-structure interaction system. The earthquake responses of the liquefiable soil foundation and pile group foundation are analyzed. According to the test results, the strain response amplitudes of the corner pile are greatly larger than those of the middle pile at the same depth except that at the top of pile. On the contrary, the strain response amplitude at the top of the middle pile is much larger than that of the corner pile. Further more, the bending moment at the top of pile increases quickly after the liquefaction of soil foundation, which is also greatly larger than that at somewhere else of the same pile. Compared with the seismic responses of pile under the non-isolated structures, the great rotational vibration of the base-isolated structures and the bearing of piles should be induced more severely due to the complicated soil-piles-isolated layer-structure dynamic interaction.