大跨斜拉桥上无缝线路伸缩力影响因素分析

Influence Factors Analysis of Expansion and Contraction Force of Continuous Welded Rails on Long- span Cable- stayed Bridge

研究目的:大跨度斜拉桥结构复杂,为"塔-索-梁"空间组合结构,在荷载作用下,其无缝线路梁轨相互作用极为复杂。本文以一座铁路常用双塔钢桁斜拉桥为例,基于梁轨相互作用原理,建立斜拉桥上无缝线路纵向力计算模型,分析主塔墩温差、斜拉索温差、主塔墩刚度、主梁刚度及结构支撑体系对钢轨伸缩力的影响,为大跨度斜拉桥上无缝线路设计提供理论依据。研究结论:(1)随着主塔墩温差增大,钢轨伸缩力减小,主塔墩温差越大,主梁主跨竖向位移就越大;(2)随着斜拉索温差增大,钢轨伸缩力增大较小,但主梁主跨竖向位移急剧减小;(3)主塔墩刚度变化对钢轨伸缩力影响较小;(4)采用漂浮体系时,钢轨伸缩力与半漂浮体系几乎一致,采用塔梁固定支撑和塔梁固结体系时,主梁左端梁缝处的伸缩力减小,但主梁右端梁缝处的钢轨伸缩力反而增大,因此在铁路大跨斜拉桥设计中建议不采用这两种支撑体系;(5)该研究成果可指导大跨度斜拉桥无缝线路设计。

Research purposes： The structure of cable- stayed bridge is a complicated special composite structure ot ＂tower - cable - beam＂. The bridge - rail interaction of continuous weldedrails is complex under the load effect. Taking a double - tower steel truss cable - stayed bridge commonly used in railway as an example, the calculation model of longitudinal force for continuous welded rail on cable - stayed bridge was established based on the theory of bridge - rail interaction. The influences of the main tower temperature, stayed cable temperature, main tower stiffness, main girder rigidity and supporting system on the expansion and contraction force of rail were analyzed for providing the theoretical basis for the design of continuous welded rail on long - span cable - stayed bridge. Research conclusions： （ 1 ） The research shows with the increase of main tower temperature, the expansion and contraction force decreases. The greater difference of main tower temperature, the vertical displacement of main girder mainspan is greater. （2） With the increase of stayed cable temperature, the expansion and contraction force increases little, but the vertical displacement of main girder main span decreases sharply. （3） The variation of main tower stiffness has little effects on the expansion and contraction force. （4）The expansion and contraction forces are almost in the same with floating system and half floating system. The expansion and contraction force in the left beam crevice of main girder is decreased when using the tower beam fixed support system and consolidation system, bat the expansion and contraction force in the right beam crevice of main girder is increased. The two kinds of support system were not recommended to use on railway long - span cable - stayed bridge. （5） The research results can provide the design of continuous welded rail on long- span cable -stayed bridge.