Site response analysis with two-dimensional DDA

As the modern society becomes more vulnerable to seismic hazard with the increasing development of sensitive infrastructure facilities, it becomes essential to be able to assess the seismic hazard in a quantifiable manner. For most practical purposes it would be sufficient to provide the structural engineers with quantitative information regarding the resonance frequency of the ground strata, and the expected amplification, given an accepted design earthquake record. For soft soil foundations a computer program such as SHAKE may be utilized for this purpose. For stiff rocks comprised of horizontal layers and inclined joints a discontinuous approach must be utilized. In this paper we test the ability of the numerical, discrete element, 2D-DDA method to perform SHAKE like site response analysis. We conclude that provided that the penalty parameter is chosen correctly 2D-DDA is perfectly capable of performing robust site response analysis in stiff and discontinuous media.