大跨公轨两用悬索桥动力特性的参数敏感性分析  

Parameter Sensitivity Analysis of Dynamic Characteristics of Long-Span Road-Rail Suspension Bridge

作　　者：张兴[1] 杜斌[1,2] 向天宇 ZHANG Xing;DU Bin;XIANG Tian-yu(Guizhou University,Guiyang 550025,China;Guizhou Shunkang Road and Bridge Consulting Co.,Ltd.,Guiyang 550000,China;Xihua University,Chengdu 610039,China)

机构地区：[1]贵州大学,贵阳550025 [2]贵州顺康路桥咨询有限公司,贵阳550000 [3]西华大学,成都610039

出　　处：《铁道标准设计》2018年第6期77-82,共6页Railway Standard Design

基　　金：贵州大学研究生创新基金项目(2017033);贵州省科技支撑计划项目(黔科合支撑2016[2047])

摘　　要：为了深入研究大跨度公轨两用悬索桥的动力特性,以贵州省在建的马岭河三号特大桥为研究对象,基于Midas/Civil建立全桥三维离散单元有限元模型,采用子空间迭代法进行模态分析,得到该桥的自振频率和振型,并采用控制变量法,分析主塔刚度、主缆刚度、加劲梁刚度、吊杆刚度、恒载集度、中央扣和横向抗风支座等六类结构关键参数对其动力特性的影响。研究结果表明:该桥基频为0.172 Hz,对应振型为主梁1阶正对称侧弯,该桥自振频率较同等跨径的普通公路悬索桥高,结构整体刚度较大;增大主塔刚度,主塔侧向振动频率提高;增大主缆刚度,主梁1阶竖向振动和扭转频率提高;增大吊杆刚度,纵飘频率有一定程度提高;增大加劲梁刚度,主梁侧弯和主梁扭转振型频率的提高显著,有助于提高结构的横向刚度和改善结构的颤振性能;而增大恒载集度,以主梁振动为主的侧弯、竖弯、扭转振型的自振频率均有不同程度的降低;中央扣和抗风支座能有效提高结构的整体刚度。To investigate the dynamic characteristics of long-span road-rail suspension bridges,a full-bridge discrete unit finite element model is established by Midas/Civil based on the 3 rdMaling River Bridge in Guizhou. Modal analysis is conducted with subspace iteration method to obtain the natural frequencies and the mode shape of the bridge. Then the control variable method is employed to analyze the effects of seven key structural parameters,including pylon stiffness,cable stiffness,girder stiffness,boom stiffness,dead load,central buckle and wind-resistance bearing. The results indicate that the fundamental frequency of the bridge is 0. 172 316 Hz and the corresponding vibration mode is the first symmetric lateral bending mode of the main girder. The fundamental frequency of the road-rail suspension bridge is higher than that of the normal highway suspension bridge,and the integral stiffness is also high.The increase of the pylon stiffness can increase the lateral vibration frequency of pylon. With the increase of the cable stiffness,the first vertical vibration and torsion frequencies of the main girder increase significantly. The increase of boom stiffness improved the lengthways flutter frequency to some degrees.With the increase of girder stiffness,the lateral bending and torsion frequencies of the main girder are increased significantly and the performances of structural lateral stiffness and flutter are improved.However,the increase of dead load intensity can decrease the lateral vibration,the vertical vibration and the torsion frequencies of the main girder by different degrees,while,the central buckle and the wind-resistance bearing can improve the integral structure stiffness effectively.

关 键 词：悬索桥 公轨两用桥 结构参数 子空间迭代法 动力特性 振型 频率 

分 类 号：U448.25[建筑科学—桥梁与隧道工程]