Fully Integrated 3D Analysis on Site-City Interaction in an Urban Transport Hub

摘要

Previous studies have shown that site-city interaction (SCI) is important for sustainable seismic design in a congested urban environment. However, due to its complexity, the phenomenon is not yet fully understood. A fully integrated 3D model was developed herein to analyze the problem using a transportation hub in Hong Kong as a testbed. The site assumes a typical downtown layout with a central plaza, a large underground chamber surrounded by 16 high-rise buildings with deep foundations. This investigation aims to explore SCI emphasizing soil-underground structure-soil interaction (SUSSI) and contamination of the site response caused by the dense building cluster. To simulate visco-elastic wave propagation, a discontinuous Galerkin spectral element code (SPEED) is employed. Key SCI effects manifest in a wavefield propagating from the buildings and surface waves trapped in-between them. The propagated wavefield travels up to 450 m with 20% increase in peak ground accelerations (PGA) compared with the free field. In the center plaza, 70% increase in PGA is observed. Furthermore, a coherency analysis was conducted to quantify the spatial variation of ground motions. The building layout and subsurface structures govern the SCI phenomena, which highlights the importance of realistic fully integrated modeling for sustainable urban design.