ABSTRACT
ABSTRACT: In current design practice, the seismic response of a structure is estimated using the free-field ground motions. However, in reality the earthquake loading is characterized by the interacting forces at the footing-soil interface. These interacting forces depend on the dynamic properties of the structure, soil and the incoming seismic waves. Consequently, the actual earthquake loading of the structure and the free-field ground motions are not the same, and the structural response cannot be properly estimated using the free-field motions. This study aimed to investigate the behaviour of soil with Structure-Foundation-Soil Interaction (SFSI). Shake table tests on a laminar box that allows shear deformation of soil were conducted to obtain the dynamic response of the soil. The difference between the soil responses under two conditions, i.e. free-field and soil with structure, were considered. The result shows that because the presence of the structure, the vertical movement of the soil was impeded and the weight increased the settlement of the soil. This altered the shear behaviour of soil and therefore changed the acceleration of the soil. This finding indicates the likelihood that the seismic response of structures cannot be obtained using free-field ground motion.
