For how large soil shear wave velocity the soil-structure interaction effects on a tall building can be neglected? – A case study

The soil-structure interaction (SSI) effects are typically ignored in modeling and analyses of the seismic response of tall buildings. This paper presents an in-depth investigation of the SSI effects on the response of a 50-story skyscraper, with a basement and on piles, as a function of the soil shear wave velocity, VS, varied between 50 and 800 m/s. A detailed three-dimensional finite element model of the structure and soil was developed in OpenSees, which was excited by vertically incident plane SV-, SH- and P-waves. The three translational and three rotational components of the response were analyzed. The SSI effects on its apparent dynamic properties (frequencies of vibration and damping ratios), floor translations and rotations, effective input base translations and rotations, interstory drifts, floor and base reaction forces and floor and base reaction moments were analyzed in the linear domain. It was concluded that the SSI effects for such a tall building are not negligible and ignoring them does not produce conservative estimates of the response. •In-depth study of soil-piles-basemnt-structure interaction for a 50-story skyscraper.•A detailed 3D finite element model of structure, basement, piles and soil was developed in OpenSees.•Apparent frequencies and damping, translational and rotational responses, etc. Are investigated.•The SSI effects for this building are not negligible.•Ignoring the SSI effects may lead to nonconservative estimates of the response.