Author(s)

F. A. Flores & J. M. Mayoral

Abstract

This paper examines the influence that cracks and discontinuities can have over the seismic response of a hypothetical soil profile using a bidimensional finite difference model. The soil is considered as having a bilinear behavior using a Mohr-Coulomb model. The soil openings are simulated with interface elements, where the soil stiffness is used to characterize the contact force when the crack closes. Transmitting boundaries were used at the edges and bottom of the model to allow for energy dissipation of the reflected waves. The effect of cracking in the seismic response was evaluated comparing the results of site response analysis with and without discontinuities, for several lengths and orientations. From the results of this investigation, insight was gained regarding the effect that discontinuities may have in the seismic response of soil deposits and soilstructure systems. Keywords: cracks, interface, seismic, finite difference model. 1 Introduction The presence of cracks or fissures on rigid soils, such as stiff clays or sandy silts, is generally related to particular subsoil conditions combined with external environmental phenomena such as long periods of drought or excessive water extraction from underground aquifers. These natural discontinuities may affect both the static and seismic performance of structures sitting on top of them. In this work, the influence of cracks and discontinuities (closed cracks) in the seismic response of a hypothetical soil deposit, and a six-story building located near by the crack, is assessed using a two-dimensional finite difference model. In this paper a discontinuity is considered as a closed crack. Thus full contact exists between both edges. Therefore only compressional forces are transmitted normally to the interface from one edge to the other. The site response is

Keywords

cracks, interface, seismic, finite difference model.