大跨度铁路独塔混合梁斜拉桥的动力特性

为研究大跨度铁路独塔混合梁斜拉桥结构参数对动力特性的影响,以岳口汉江特大桥为背景,利用MIDAS/Civil建立有限元模型,分析了边中跨比、结构自重和刚度、钢混比等参数及有无辅助墩和横向抗风支座对桥梁动力特性的影响。结果表明:该桥振型排列合理,耦合程度低;钢混比和边中跨比对主梁基频影响极大,辅助墩可以有效提高桥梁的整体刚度;无横向抗风支座对主梁振型影响较大,但对桥塔振型影响不大;主梁刚度和自重对本桥前3阶振型的振动频率影响显著;桥塔自重主要影响主塔侧弯和纵弯频率;斜拉索刚度主要影响主梁竖弯和主塔纵弯频率。

Dynamic Characteristics of Large Span Railway Single Pylon Hybrid Girder Cable-stayed Bridge

To study the inf luences of the structural parameters of large span railway single pylon hybrid girder cable-stayed bridge on the dynamic characteristics,Yuekou Hangjiang bridge was cited as an example and a spatial f inite element model was established on MIDAS/Civil.The inf luences of ratio of side-span to mid-span,structural self-weight and stiffness,steel-concrete ratio and other parameters,auxiliary pier and transverse wind resistant bearing on the dynamic characteristics of the bridge were analyzed.The results show that the bridge has the rational vibration modes and dense frequency spectrum distribution.The inf luence of steel-concrete ratio and ratio of side-span to mid-span on the base frequency is great.The auxiliary pier can effectively improve the overall stiffness of the bridge. W hen there is no transverse wind resistant bearing,the vibration mode of the main girder is greatly affected,but the vibration mode of the tower is little affected.The stiffness and self-weight of the main girder have signif icant inf luence on the vibration frequency of the f irst three modes of the bridge.The self-weight of the bridge tower mainly affects the lateral and longitudinal bending frequencies of the main tower.The stiffness of cables mainly affects the vertical bending frequency of the main girder and the longitudinal bending frequency of the main tower.