Evaluation method for seismic behaviors of underground frame structures

The study on seismic responses of underground structures is focusing on the specific structure under a given earthquake, and the safety of the structure is not known under the seismic responses. Therefore, much attention should be paid to the evaluation method for underground frame structures during earthquake. The researches on the evaluation methods for underground structures are summarized. A new evaluation method is presented based on the former research results and Chinese code for seismic design of buildings. The story drift angle is adopted to evaluate the deformability of structural components, and the effective stress value is employed to evaluate the strength of structural components in the method. Then, three-dimensional analysis models for underground frame structures, such as subway stations and civil defense engineering, are established and the seismic responses are calculated, including horizontal relative displacement and inner forces of structures. The seismic behaviors of these underground structures are evaluated. It can be seen from the analysis that the proposed evaluation method can be used to evaluate the seismic behaviors of underground frame structures, whereas it needs to be improved. The research results and approach are helpful for the supplementation and perfection of underground structures in Chinese code for seismic design of buildings.