Time-domain two-dimensional site response analysis of non-homogeneous topographic structures by a hybrid BE/FE method

In this paper, an advanced formulation of the time-domain, two-dimensional hybrid finite element-boundary element method (FEM/ BEM) is presented, and applied to carry out site response analysis of homogeneous and non-homogeneous topographic structures subjected to incident in-plane motions. Seismic responses of half-plane, horizontally layered site, alluvial valley and ridge sections subjected to incident P and SV waves are analyzed in order to demonstrate the applicability and efficiency of the presented method. The numerical results show that hybrid BE/FE methods require smaller time steps than those needed by BEM schemes. They also show that in case of surface irregularities with height to half-width ratio of up to one, the topography effect could be noticeable, if incident waves have wavelengths of less than approximately eight times the width. (c) 2006 Elsevier Ltd. All rights reserved.