城际铁路连续梁桥抗震计算方法对比分析

Comparative Analysis of Seismic Design Methods for Intercity Railway Continuous Bridge

研究目的:城际铁路桥梁在多遇和罕遇地震作用下的设计检算方法选择,对于桥梁结构的安全性具有重要作用。为深入研究城际铁路连续梁桥的不同抗震计算方法的特点,并确定在不同计算阶段的方法采用,本文以大连市金州新区至普湾新区的一座城际铁路预应力混凝土连续梁为例,首先介绍铁路规范简化算法、反应谱法和弹性、弹塑性时程分析法的计算流程,然后运用三种方法分别对该连续梁桥进行多遇地震和罕遇地震作用下响应分析,并进一步采用简化算法和弹塑性时程分析法计算罕遇地震下的延性系数,对比三种方法的墩顶位移、墩底弯矩和墩底剪力的计算结果。研究结论:(1)对于连续梁桥,多遇纵向地震计算采用三种方法差异不大;(2)多遇横向地震计算应采用反应谱法或时程分析法,采用简化算法偏危险;(3)罕遇地震作用计算应采用弹塑性时程分析法,更为经济合理;(4)罕见地震作用计算采用简化算法或反应谱法结果失真,会严重放大墩底弯矩,增加配筋量;(5)本研究成果在铁路连续梁桥的抗震设计领域具有一定的指导和借鉴意义。

Research purposes： The selection of seismic design method for intercity railway bridges under frequent and rare earthquake, has a significant influence on safety of bridge structure. In order to study the characteristics of different seismic calculation methods for intereity railway continuous girder bridges, and determine the method used in different calculation phases, taking a Jinzhou - Puwan intercity railway continuous bridge of Dalian as the engineering background, this paper firstly introduces the calculation process of railway code simplified method, response spectrum method, elastic and elastic - plastic time - history analysis method. Furtherly, the seismic analysis of intercity railway continuous bridge under frequent and rare earthquake by using three analysis method has been conducted. Finally, the results of the top displacement, the bending moment and the shear force of piers are compared Research conclusions： （ 1 ） For continuous bridge, when it comes to longitudinal seismic effect under frequent earthquake excitation, there is little difference among railway code simplified method, response spectrum method and elastic time - history analysis. （2） When considering the horizontal earthquakeseismic effect under frequent earthquake,response spectrum method and elastic time -history analysis are preferred, using railway code simplified method to be dangerous. （3） Faced with rare earthquake, elastic -plastic time -history analysis method is more reasonable and economical. （4） Faced with rare earthquake, using railway code simplified method or response spectrum method results distortion, will seriously enlarge the pier bottom bending moment and increase the amount of reinforcement. （5） The research results of this paper have some guidance and reference for the seismic design of continuous girder bridges.