Seismic Performance Evaluation Method of Underground Frame Structures Considering the Vertical Seismic Capacity of Structural Components

The seismic performance of large underground structures can be evaluated from two perspectives, namely the horizontal interlaminar deformation and the vertical loading-carrying capacity. The current seismic analysis methods focus on the horizontal seismic performance with the interlaminar drift ratio as the evaluation index. It is difficult to fully reflect the vertical failure characteristics of the overall structure. This paper aims to develop an evaluation method to comprehensively evaluate the seismic performance of underground frame structures. The quantitative evaluation indexes, i.e. the vertical loading-carrying risk factor of columns and the vertical deflection risk factor of slabs, were defined to evaluate the seismic performance of underground frame structures. Then, the seismic performance evaluation method was established and the evaluation processes were described. Seismic response analysis of an underground frame structure with different spans on the upper and lower stories was conducted, and the seismic performance of the structural components and overall structure was quantitatively evaluated by using the proposed evaluation method. The seismic response laws of columns and slabs were analyzed and the potential failure mode of the structure was clarified. Furthermore, the failure mechanism of the structure was explained in detail. Numerical results presented that the proposed evaluation method can effectively identify the seismic-induced weak components and failure modes of underground frame structures, and thus has guiding significance for the seismic design of the underground frame structures.