Modeling Nonlinear-Inelastic Seismic Response of Tall Buildings with Soil–Structure Interaction

Abstract

Soil-structure interaction (SSI) effects are of interest for the seismic analysis and the design of tall buildings on shallow foundations, particularly when both the structure and soil undergo inelastic demands. The objective of this paper is to evaluate the interaction of nonlinear soil-structure systems using the direct fully-coupled approach for modeling SSI. Numerical simulations of linear and nonlinear tall buildings, combined with either fixed-base conditions at the ground level or an explicit soil domain, are performed. The soil domain was modeled assuming either linear elastic isotropic or multiple yield surface plane strain continuum constitutive models. An archetype 30-story building supported on a mat foundation was modeled using nonlinear link elements to control geometry, stiffness, and strength. Structural stiffness and mass profiles were algorithmically generated to satisfy prescribed modal characteristics of tall buildings and achieve a more realistic response. The influence of nonlinear material responses for both structure and supporting soils subjected to selected earthquake time histories is quantified using drifts, accelerations, displacements, hysteretic energy, and transfer functions. Nonlinear analyses considering SSI largely influenced the computed seismic structural response presented in this paper, showing a significant decrease of the seismic demands when compared to those demands obtained with linear SSI models, which impacts the structural behavior and has practical implications in seismic-resistant designs.