Numerical Simulations of the Seismic Response of a RC Structure Resting on Liquefiable Soil

Abstract

The seismic response of buildings resting on liquefiable soil is a complex problem that is still poorly understood despite numerous studies on the topic. This paper attempts to enhance the understanding of this phenomenon by simulating an RC structure resting on liquefiable soil and subjected to seismic shakes. The solid-fluid fully coupled analysis was conducted with OpenSeesPL utilizing 58 earthquake records to simulate a wide range of shaking scenarios. In addition, the effect of the soil density and the thickness of the liquefiable layer were examined. It was noted that the liquefaction-induced settlement of the building increased as peak ground acceleration (PGA) increased, where the percentage increase ranged between 2.5% and 888.0% depending on the soil density, thickness of the liquefiable layer, PGA and the predominant frequency of the seismic shake. However, a scatter of the relationship between the PGA and the liquefaction-induced settlement was also noted due to the effect of the predominant frequency of the seismic shake. In addition, a reduced effect from soil density on the liquefaction-induced settlement was observed, where the settlement changed by up to 55% as the soil density changed from loose to medium, and by 68% as the density changed from loose to dense. Additionally, the results of the lateral displacement of the building did not show a definite trend with the increase in PGA, which could be attributed to the complex interaction between PGA amplification and the predominant frequency of the seismic shake as the liquefiable soil layer thickness changed.