Evaluation of Substructure and Direct Modeling Approaches in the Seismic Response of Tall Buildings

Several numerical modeling approaches have been reported in technical literature to determine the seismic soil-structure interaction (SSI) effects in buildings. As part of earthquake-resistant designs of tall buildings, considering SSI effects in the analysis provides more realistic features of its performance during a future seismic event. SSI effects are currently incorporated in building designs using classical impedance functions in the form of translation and rocking springs concentrated or distributed along the foundation level. Numerical simulations using springs and dashpots performed in OpenSees are presented in this paper to simulate the flexibility and the damping of the soil. The results are compared with those obtained using direct approaches considering soil-foundation-structure system in a continuum form. The pressure dependent multi yield (PDMY02) constitutive soil model is used to represent the soil domain underneath archetype tall buildings when subjected to different earthquake time histories. The main goal of this paper is to estimate the difference on the computed seismic response of tall buildings using both SSI modeling approaches. It is concluded that regardless of the SSI modeling approach, the seismic response of tall buildings is affected by the inclusion of SSI effects when compared to conventional fixed-base structure models.