Large-scale shake table testing of pile group-bridge model in inclined liquefiable soils with overlying crusts

Abstract

Large scale shaking table tests were performed to investigate the failure mechanism of pile group-bridge system subjected to liquefaction-induced lateral spreading. The tests comprised two cases: Case L which refers to a bridge model supported by a 2 × 2 pile group embedded into the inclined liquefiable soils with crusts; and case R which refers to the same bridge model fixed to a rigid foundation. The experimental details are provided and typical test results are elucidated. The failure mechanism of the pile group-bridge system under strong earthquakes is revealed. The results indicate that the lateral peak soil displacement profile has a linear distribution, while the lateral permanent displacement profile has a cosine distribution pattern. It was also found that the pile is prone to damage and bending failure both at its head and at the bottom of saturated sand where it is fixed into bearing stratum. For the pile group-bridge system, the liquefaction-induced lateral spreading causes the failure position to move from the pier bottom to the pile head. In addition, the pier bottom is more likely to experience damage under strong earthquakes in case R than in case L, while the opposite is true during weak earthquake excitation.