大跨度铁路悬索桥纵向位移特征及纵向支承要求

Longitudinal Displacement Characteristics and Longitudinal Supporting Requirements for Long-Span Railway Suspension Bridge

为研究大跨度铁路悬索桥合理的纵向支承体系,从理论上分析大跨度悬索桥的刚度特性及大跨度铁路悬索桥的纵向位移特征,并以某主跨1060 m上承式钢桁梁铁路悬索桥为例,分析大跨度铁路悬索桥在列车荷载作用下的梁端纵向位移特征,研究不同纵向支承体系对悬索桥加劲梁梁端纵向位移及速度的影响,最后给出大跨度铁路悬索桥纵向支承设计的要求。结果表明:竖向荷载作用下,结构产生显著纵向位移,是悬索桥的基本结构特征;竖向荷载作用在悬索桥加劲梁上不同位置时,加劲梁梁端纵向位移差别大;铁路列车作为快速移动荷载,具有规则、连续的特征,从而导致铁路悬索桥梁端频繁快速活动,此为梁端伸缩装置、支座、吊索耐久性的控制性因素。

The stiffness property and longitudinal displacement characteristics of the long-span railway suspension bridge are theoretically analyzed to figure out rational longitudinal supporting systems for the bridge of this type.A deck-type steel truss girder railway suspension bridge with main span length of 1060 m is cited as an example.The characteristics of girder-end longitudinal displacements of the long-span railway suspension bridge under train loads are analyzed,and the influence of different longitudinal supporting systems on the girder-end longitudinal displacement and moving speed of the stiffening girder of suspension bridge is studied and the design requirements of longitudinal supports for long-span railway suspension bridge are given.The results show that vertical loads can cause evident longitudinal displacement in the suspension bridge,which is considered the fundamental structural characteristics of suspension bridge.When vertical loads act on different locations of the stiffening girder of suspension bridge,the differences of girder-end longitudinal displacements are big.Train loads are fast moving loads that are regular and continuous,and girder ends of a railway suspension bridge are sensitive to these loads,therefore,train loads governs the durability of expansion joints,bearings and hanger cables.