Pounding induced overturning resistance of FPB-isolated structures considering soil-structure-interactions

This study explores the overturning resistance performance of friction pendulum bearing (FPB) isolated structure when pounding occurs during earthquake actions, and considers the soil-structure-interaction (SSI) effect. The dynamic responses and overturning resistance performance of structures under a series of seismic records were comprehensively analyzed for three different types of soils and fixed-base structure. The effects of displacement ratio, equivalent radius ratio and friction coefficient ratio on the overturning resistance performance of the isolated structures were evaluated through parametric study. It is demonstrated that the system exhibit superior overturning resistance performance in soft soil foundation case, surpassing the performance when SSI is ignored. However, the overturning resistance performance of structure with a dense soil foundation is similar to the fixedbase structures. Moreover, the results reveal that the overturning resistance coefficient initially increases and then decreases with an increase in the equivalent radius ratio and friction coefficient ratio subjected to pulse-type seismic record, but it increases with an increase in the pounding displacement ratio. The overturning resistance performance increases with an increase in the equivalent radius ratio, friction coefficient ratio, and displacement ratio when the structures are subjected to non-pulse-type seismic records.