Effect of soil - structure interaction constitutive models on dynamic response of multi-story buildings

Abstract

The choice of an adequate soil constitutive model in a dynamic soil-structure interaction (SSI) problem has always been a challenge. Linear-elastic and elastic-perfectly plastic Mohr-Coulomb models are implemented in commercial software and extensively used in dynamic studies due to their ease of application. The objective of this paper is to assess the reliability of these two soil models in dynamic SSI finite element models. This is realised by comparing their structural dynamic responses with that of small strain hardening model, proven effective in dynamic analysis. Two - dimensional finite element models under plane strain conditions are generated by the use of PLAXIS software. The dynamic response of three concrete frame buildings of different slenderness ratios is evaluated when excited by a strong earthquake. The soil medium beneath the building structures is considered as a homogeneous half space with viscous boundary conditions at the truncated interface and is varying between loose, medium and dense sand. This paper demonstrated the inadequacy of the linear and Mohr-Coulomb models in capturing the real soil behaviour as their structural dynamic response is largely dissimilar to the small strain hardening behaviour.