A modified simplified analysis method to evaluate seismic responses of subway stations considering the inertial interaction effect of adjacent buildings

Abstract

A modified simplified analysis method is proposed in this paper to evaluate seismic responses of subway stations in dense urban environments. Based on the dynamic analysis of the underground structure-soil-adjacent building interaction (SSSI) model, the seismic response of subway station was distinguished as the kinematic interaction (KI) effect (induced by the free-field movement) and the inertial interaction (II) effect (induced by the vibration of adjacent building). In order to comprehensively and simply consider the KI and II effects, a modified model was established after simplifying the analytical solution of underground structural seismic response. Owing to acquiring the dynamic response via static modelling and calculation, the method proposed herein requires a shorter analysis time and incurs a lower cost. In addition, a typical subway station-soil-ground building system in an east city in China was selected as the case-history to verify the modified method and further evaluate its computational accuracy. The traditional response displacement method and dynamic time history analysis method were also conducted in simulation as a comparison method and standard method, respectively. The case study demonstrates that referencing the results obtained by the dynamic time history analysis method (D-M), the maximum story drift and maximum internal force (including bending moment, axial force and shear force) errors of the traditional response displacement method (T-M) reached −28% and −48%, respectively. Obviously, this method is dangerous in designing due to its smaller computing results. In contrast, the modified method (M-M) which can accurately reflect the impacts of adjacent buildings, is a more accurate and safer analysis method (two seismic response indexes of the modified method generally exceeded the actual values, and more gratifying is that the errors were less than 12%). Therefore, the modified simplified analysis method proposed is a higher accuracy, safer design, less time consumed, and faster analysis process method, which can be used to substitute the traditional method in the aseismic performance and dynamic response analysis of subway stations in dense urban environments.