Implementation of Soil-Foundation-Structure Interaction in Nonlinear Response History Analysis—A Design Case Study

There are configurations of a structural-system model where soil-foundationstructure interaction (SFSI) effects need to be considered. The objective of incorporating these effects is to model the system more realistically than as a theoretically flexible building structure on a rigid-base foundation that is subjected to free-field ground motions. Effects such as foundation and soil inertia, damping, flexibility and strength can be incorporated directly into the numerical model. Of interest in this paper are the kinematic effects, base-slab averaging and embedment effects, which result in spatial variations of input motions on the foundation boundaries. Because this variation of ground motion cannot be modeled directly when using current state-of-the-practice numerical-simulation tools, modifications accounting for these effects need to be made to the ground-motion records a-priori. This paper presents a case study where soil-foundation-structure interaction was incorporated in the numerical simulation used for design.