Simplified evaluation method for seismic performance of integrated station-bridge structures

With the prosperous development of the railway and urban rail transit engineering in recent years in China,integrated station-bridge structure becomes the predominant structure type for the key stations. Owing to lack of the special code for such a type of structures,the seismic design of an integrated station-bridge structure must meet the requirements of the existing Code for Seismic Design of Buildings and Code for Seismic Design of Railway Engineering simultaneously. But the design philosophy of the two codes above mentioned is essentially different. Here,taking the main structure of Beijing South Railway Station as an example,based on the universe software of Midas /Gen and Sap2000,the global structure model considering the multiple modes effect of upper truss structures and the corresponding simplified model were constructed,respectively. The rationality of the simplified model was verified by comparing the results from the analysis of natural vibration characteristics,the response spectral analysis and the dynamic analysis of time history.The plastic yielding mechanism and the seismic performance were investigated in detail with the pushover analysis( considering the multiple patterns of the lateral loading) and the incremental dynamic analysis( IDA),respectively. It was shown that the proposed simplified model can essentially reflect the behavior of the main structure under the designated earthquake; the pushover analysis method based on the improved lateral loading pattern considering the multiple modes combination can be applied to evaluate the seismic performance of integrated station-bridge structures.