Parametric Study on Seismic Topography–Soil–Structure Interaction; Topographic Effect

Site and Soil–Structure Interaction (SSI) considerably affects ground seismic motion characteristics. Since some structures are constructed on top of slopes or hills, it is essential to assess the seismic response of the topography–soil–structure system. The current research evaluated important topographic parameters in topography-soil-structure interaction. In this paper, by using numerical method of finite difference, significant parameters of single-faced slope topography were studied. The results showed that geometry of the topographic irregularity could significantly alter the SSI mechanism. The effects of free field soil thickness were also investigated. It was revealed that the mechanism of the SSI was affected by changing the free field soil thickness; yet, due to pure topographic it did not significantly affect the amplification of the acceleration. The effect of soil critical damping ratio in altering ground response was more pronounced for topographic effects. Studying the structure-soil impedance ratio suggested that impedance ratio had considerable effect on seismic ground motion under simultaneous effects of the SSI and the topography. Slope height, as one of the geometrical properties of the system, affected seismic response of the topography with and without structure. The results of this research were presented as spatial distribution of acceleration. Also, transfer functions of the SSI on the slope were also calculated.