Rocking responses of free-standing rigid blocks on flexible foundation with a slope under earthquakes: structure-foundation interaction effects

To simulate the dynamic rocking responses of free-standing rigid blocks on a flexible foundation with a slope, a modified concentrated spring model (CSM) is proposed. The shaking table model test of a rigid steel frame structure was conducted, and the test results indicated that the rocking response of the structure can be effectively predicted by the proposed model. Utilizing the modified CSM, the interaction effects between the structure and foundation on the rocking of the free-standing rigid blocks on a flexible foundation with a slope were investigated. The influences of spring stiffness, viscous damping, and the frictional coefficient on the rocking of the rigid blocks under pulse-type ground motions were analyzed numerically. The results indicated that decreasing the spring stiffness and increasing the viscous damping coefficient of the modified CSM can reduce the number of impacts and rocking duration, while the friction coefficient has a significantly non-linear effect on the rocking response.