Responses of Liquefiable Soils in Pile Group Foundations of Tall Buildings from Shaking Table Tests

Abstract

The responses of liquefiable soils around pile group foundations of tall buildings to earthquakes were measured using acceleration arrays in shaking table tests. System identification techniques were used to analyze the measured accelerations and pore pressures and to calculate the shear stress and shear strain in the soil inside and outside the pile group of a 12-story building as well as the soil shear moduli and damping. The analysis shows that the calculated soil stiffness is similar to the stiffness determined using laboratory tests and that the soil damping is higher. It also shows that pore pressure buildup reduces the shear wave velocity and the soil stiffness.