Parametric study on interaction behaviour of high-rise buildings with underground structures under seismic loads

This study mainly focuses on the coupling interaction effects of aboveground and underground structures in high-rise structures. A simplified numerical finite element model was developed using the beam on a nonlinear Winkler foundation approach and a nonlinear multi-degree-of-freedom flexural-shear model. Parametric analyses were performed to investigate the influence of different structural parameters and soil conditions on this coupling interaction effect. Numerical results showed that the underground structure, together with the soil-structure interaction effect, caused an increase in seismic deformation response and a decrease in acceleration response of aboveground structures. The phenomenon was more pronounced for large span and shallow embedded underground structures. However, this phenomenon would change in soft soil conditions because the seismic input at the foundation level changes due to the embedment effect of underground structures. The aboveground structure increased the seismic story shear force of underground structures, and this phenomenon was more noticeable for the aboveground structure with long periods and multi-story podiums. The structural coupling interaction varies with the structural dynamic characteristics and may have different effects on the structural seismic response. Furthermore, the natural period of the aboveground structure, the span of the underground structure, and soil conditions have inconsistent effects on structural coupling interactions.