Quantification of seismic performance index limits and evaluation of seismic fragility for a new rectangular prefabricated subway station structure

To promote the acceptance of prefabricated technology in underground engineering, the numerical seismic fragility analysis of a prefabricated underground structures was scrutinized. A method to quantify the limit values of the seismic performance index of rectangular prefabricated subway station structure was proposed. In addition, seismic fragility curves of the two-story three-span prefabricated subway station structure were constructed based on peak ground velocity (PGV) and peak ground acceleration (PGA), which can be used as an effective tool to quickly evaluate the seismic performance of this type of prefabricated underground structure, and compared with the cast-in-place subway station structure. The results demonstrate that the ground motion and site class have an intertwined influence on the dynamic response of the underground structures. That is, as the site equivalent shear wave velocity decreases, the ground motion characteristics have a greater influence on the underground structure dynamic response and its susceptibility to damage. For shallow buried multi-layer underground prefabricated structures, the PGV is the best seismic intensity measure (IM) for all site classes. The prefabricated subway station structure is found to be less vulnerable to damage than the cast-in-place subway station structure.