Comparative Analysis of Numerical Simulation and Model Test of Base-Isolated Structures on Variable-Stiffness Foundation

Abstract

Base isolation technology is considered a highly effective approach for mitigating seismic damage to buildings during earthquakes. The stiffness of foundation soil plays a crucial role in influencing soil-structure interaction, thereby affecting the seismic response of the structure. In the present study, a three-dimensional finite element model was developed to evaluate the seismic behaviors of a base-isolated structure under varying conditions of foundation soil stiffness. The dynamic response characteristics of base-isolated structures were investigated by modifying the duration compression ratio and peak acceleration of seismic ground motions, with findings validated against results from shaking table experiments. The finite element analysis outcomes demonstrate strong agreement with the experimental data, confirming that as the relative stiffness between the superstructure and the foundation soil increased, the soil-structure interaction intensified. This enhanced interaction amplified the dynamic response of the structure and raised the liquefaction susceptibility of the foundation soil. It was also confirmed that the isolation effect of the structure worsened with increasing relative stiffness. As such, when designing base-isolated structures for seismic events, it is essential to consider the influence of the relative stiffness between the structure and the foundation soil.