Physical and Numerical Modeling of Seismic Soil-Structure Interaction in Layered Soils

The structural response of buildings subjected to seismic loads is affected by local site conditions and the interaction between the structure and the supporting soil media. Seismic centrifuge model tests were conducted on two layered clay soil profiles at 80 g field to investigate soil-structure interaction and dynamic response of foundation. Several earthquake-like shaking events were applied to the models using an electro-hydraulic shaking table to simulate linear and nonlinear soil behavior. Results showed that the foundation input motion was significantly amplified in both models, especially for weak earthquake motions. Seismic soil-structure interaction was found to have an important effect on structure response by increasing the amplification of foundation input motion. A 3D finite difference numerical model was also developed to simulate the response of centrifuge model tests and study the parameters that affect the characteristics of earthquake at the base of the structure. The results indicated that the stiffness and stratification of the soil profiles had a significant effect on modifying the foundation input motion.