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Soil-structure interaction (SSI) effects are relevant for the seismic analysis of tall buildings on shallow foundations since the dynamic behavior of structures is highly affected by the interaction between the superstructure and supporting soils. As part of earthquake-resistant designs of buildings, considering SSI effects in the analysis provides more realistic estimates of its performance during a seismic event, particularly when both the structure and soil undergo large demands that can compromise serviceability. Oversimplifications of structural or soil modeling in the analysis introduces variability and biases in the computed seismic response. The main goal of this dissertation is to investigate the interaction between archetype tall buildings and its supporting soils using numerical simulations. This dissertation develops the following objectives: i) to estimate the differences in the seismic performance of archetype tall building under different SSI approaches and compared to idealized fixed-base conditions; ii) to evaluate the seismic performance of tall building models by estimating intensity measures and engineering demand parameters (EDPs); iii) to assess the influence of SSI in the earthquake-induced losses of the structures; and iv) to evaluate the interaction of soil-structure systems using nonlinear constitutive models. To achieve these goals, numerical models of linear-elastic and nonlinear-inelastic tall buildings supported on mat foundation, combined with either fixed-base conditions at ground level or an explicit soil domain, are subjected to different earthquake time histories. The influence of SSI is quantified using structural and soil demands. It is concluded that the seismic response of tall buildings is largely affected by the inclusion of SSI effects when compared to conventional fixed-base structure models. SSI changed the computed seismic demands of the tall buildings in terms of inter-story drifts, peak horizontal accelerations, seismic-induced settlements, and losses compared to idealized buildings with fixed-base conditions. Nonlinear analyses show a significant decrease of EDPs when compared to those demands obtained with linear models. Energy distribution among both supporting soils and structure vary significantly as EDPs induce stresses and strains in the building beyond the onset of structural yielding. SSI impacts the structural and soil behavior and has practical implications in seismic resistant designs. |
