大跨度钢桁梁铁路斜拉桥刚度参数敏感性分析

Sensitivity of structural stiffness parameters of long-span steel truss cable-stayed railway bridge

针对某大跨度钢桁梁铁路斜拉桥方案,采用变化结构刚度方法研究梁、索、辅助墩等构件刚度对桥梁结构及行车性能影响。结果表明,增大桁宽能显著增加桥梁横向抗弯刚度,但对车辆走行性影响有限;增加桁高或斜拉索面积能显著提高桥梁竖向基频、降低车桥竖向响应;桥面系对桥梁结构整体刚度贡献不大,对车辆响应影响有限;设置辅助墩可提高斜拉桥竖向刚度、降低车辆竖向加速度及梁端竖向折角等。

Aiming at the design of a long-span cable-stayed railway bridge,the effects of the stiffnesses of girder, cables and auxiliary piers on the bridge structure and the runing performance of vehicles were analyzed.It is shown by the analysis results that the increase of truss width can significantly increase the lateral bending stiffness of the bridge,but has a limited impact on train running performance.Increasing the truss height or cable cross section area can notably increase the fundamental vertical bending frequency and reduce the response of vehicle-bridge systems.Local bridge deck system contributes slightly to the overall bridge stiffness and has a limited impact on the vehicle response.Auxiliary pier can improve the vertical stiffness of the bridge,reduce the vehicle vertical acceleration and the vertical rotation angle at girder ends.