坡度对连续梁桥梁端扣件上拔力的影响研究

Research on the Influence of Bridge Slope on Uplift Force of the Fasteners at Continuous Beam Ends

研究目的:大跨桥梁上铺设无砟轨道时,桥梁坡度、桥梁跨度及梁体温度变化会对梁端扣件受力产生影响,本文通过建立坡度桥梁扣件受力分析计算的有限元模型,研究连续桥梁位于坡道上时梁体坡度、梁体温度变化、桥梁温度跨度以及相邻简支梁桥固定支座布设位置对梁端扣件受力的影响。基于线路运行条件下可能发生的不利荷载组合,从扣件受力角度出发,确定不同墩高、不同温度跨度连续梁桥适应的坡度限值,为山区大跨桥梁上的无砟轨道设计提供理论指导。研究结论:(1)考虑坡度上桥梁变形对扣件受力影响时应考虑桥梁坡度对扣件受力方向的影响;(2)坡度桥梁梁缝处扣件受到附加力最大值随着桥梁坡度、温度变化幅度、连续梁温度跨度的增加而呈线性增大,而相邻简支梁固定支座位于下坡段时对扣件受力较为有利;(3)考虑线路运营中出现的最不利荷载组合,从梁端扣件受力不超限出发得到不同桥墩高度、不同温度跨度连续梁桥适应的坡度限值,在梁缝处铺设过渡板时可以大幅度提高连续梁桥适应的坡度限值;(4)该研究成果可用于指导山区铁路桥梁和无砟轨道设计。

Research purposes： If ballastless track was laid on long - span bridges, the gradient, span and temperature change of bridge will have impact on force of fasteners at beam end. A finite element model which could calculate the force of fasteners on sloping bridges was established. The influences of bridge gradient, temperature variation, temperature span and the layout of fixed bearing of the adjacent simply supported beam bridge on fastener force were analyzed with the model. The maximum gradients of continuous beam bridges with different height piers and temperature spans were determined based on the fastener force under the disadvantageous load effect combination which might occur during the operation. The value could provide theoretical guidance for the design of ballasdess track on long - span bridges mountainous area.Research conclusions： （1） The influence of the gradient of bridge on the direction of fasteners force should be considered when calculating the fastener force affected by the deformation of sloping bridge. （2） With the increasing of gradient, the temperature variation and the temperature span, the maximum additional force of fasteners increases linearly. The configuration with the fixed bearing of simply supported bridge adjacent to the continuous beam bridge laying on the direction of fall is beneficial to the fastener. （3） In order to make sure that the fastener force does not exceed the limit value under disadvantageous load effect combination, the maximum gradients of continuous beam bridges with different height piers and temperature spans are acquired, and the laying transition slab between the ends of two beams can increase the maximum gradients. （4） The results can be used to guide the design of bridge and ballastless track.