单柱式连续刚构铁路桥结构不对称性地震响应分析

Analysis of the Unsymmetrical Earthquake Response of the Single-Post Continuous Rigid-Structured Railway Bridge

以大准铁路增二线内蒙古黄河连续刚构特大桥为工程背景,应用有限元程序Midas/Civil建模,采用反应谱分析法,研究了上部结构左右边跨长度不对称与下部结构桥墩高度不对称时连续刚构桥的抗震性能。研究结果表明:桥墩高差不对称引起的结构地震响应较左右边跨不对称明显,在进行抗震设计时应取小的桥墩高差,同时不应该放松两桥墩的设计。

With the continuous rigid-structured mega bridge across the Yellow River in Inner Mongolia of the 2nd Added Line of the Dazhun Railway as a practical example,a model is established with the help of the finite element program of Midas/Civil in the paper. The anti-earthquake performance of the continuous rigid-structured bridge is studied both when the length of the left and right side spans of its upper structure is unsymmetrical and when the height of the piers of the lower structure is unsym- metrical. The result of our research shows that the structural earthquake-caused response resulting from the unsymmetricality of the height difference between two piers is more obvious than that resulting from the unsymmetricality of the side spans,owing to which the smaller height difference between two piers should be chosen and meanwhile much attention should also be paid to the design of the two piers when an anti-earthquake bridge is designed.