后加钢支撑加固铁路桥梁的力学性能研究

Research on the Mechanical Property of Railway Bridge Strengthened with Adding Steel Braces

研究目的:针对既有铁路混凝土简支双T桥梁在列车提速以及货车轴重不断增加导致桥梁横向振幅过大的问题,本文提出一种在腹板之间增设钢支撑的加固方法,该加固方法施工简单,工期短,不中断列车的正常运行,且对桥梁竖向性能和下部结构影响较小。并通过有限元分析软件ANSYS及多体动力学软件Universal Mechanism(UM)对桥梁加固前后静力性能及车桥耦合动力性能进行分析,以验证加固效果。研究结论:(1)不同的支撑布置型式对增加桥梁的横向刚度影响较大,其中加强梁端以及梁体下部的连接对增加梁体的横向刚度更为有效;(2)桥梁跨中附近的支撑对增加桥梁的横向刚度基本没有影响;(3)该加固方法能有效地增加桥梁的横向刚度,但并未因为过大的增加桥梁自重而影响桥梁的竖向刚度,因此对桥梁的竖向动挠度以及桥梁的下部结构影响较小;(4)轨道不平顺谱作为车桥耦合系统的主要激励源,在进行车桥耦合仿真分析时要合理的选择轨道不平顺谱;(5)桥梁经过加固后能够满足列车提速及轴重增加的运营要求;(6)该加固方法适用于桥梁横向振幅超限且工期紧张以及减小对下部结构扰动的铁路既有简支桥梁的加固。

Research purposes： In view of the existing increasing speed of train and axle load of freight train 1 concrete simply -supported double T railway bridge in the eading to the problems of large bridge transverse amplitude, a retrofit measure with adding steel braces between web plates for the railway bridge is proposed in this paper. This retrofit method is simple in construction, and can shorten the construction period. It also doesnt interrupt the normal operation of the train, and has little effect on the vertical performance and substructure of the bridge. The static performance of the bridge and dynamic interaction between train and bridge are studied through the finite element analysis software ANSYS and multi -body dynamics software Universal Mechanism （UM）. Research conclusions： （ 1 ） Different types and layouts of braces have large effect on increasing the transverse stiffness of the bridge. The transverse stiffness of beam body increases more effective when strengthening the tie - beam and lower part of the beam body connection. （2） The braces near the mid - span of the bridge have little effect on increasing the transverse stiffness of the bridge. （3）This retrofit method can effectively increase the transverse stiffness of the bridge, but does not influence the vertical stiffness of the bridge because of adding too much weight of the bridge. So it has little effect on the vertical performance and substructure of the bridge. （4） Track irregularity spectrum is the main source of the vehiclebridge coupled system, it is necessary to choose reasonable track irregularity spectrum in the vehicle - bridge coupled simulation analysis. （5） After retrofit the bridge can satisfy the operational requirement with increase of the train speed and axle load. （6） This retrofit method can be used for the existing concrete simply - supported railway bridge when the transverse amplitude is transfinite, construction schedule is very tense and it can effectively reduce disturbance for the lower structure of the bridge.