“站桥合一”式车站结构抗震性能评估的简化方法

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

近年来随着我国铁路与城市轨道交通的快速发展,"站桥合一"式车站结构体系已经成为大型枢纽式车站的首选结构型式,而此种结构体系的抗震设计却缺乏专用的抗震设计规范,设计结果要分别满足现有《建筑抗震规范》与《铁路工程抗震设计规范》两个不同设计理念的规范。以典型"站桥合一"式枢纽车站-北京南站为例,采用Midas/Gen和SAP2000结构分析软件,分别建立了考虑上部网架效应的整体模型与简化模型,采用自振特性分析、反应谱分析与时程响应分析方法验证了简化模型的合理性;针对简化模型,分别采用多种侧向力加载模式的Pushover分析和增量动力分析(IDA)方法研究了简化模型的塑性屈服机制和性能特点,研究表明:简化模型可以反映主体结构在设定地震下的地震行为,基于改进的模态组合方法的侧向力加载模式下的Pushover分析方法适合于站桥合一车站结构的抗震性能评估。

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.