高速铁路大跨度钢桁梁桥典型病害及运营安全性分析

Analysis of Typical Deteriorations and Operation Safety of Long-Span Steel Truss Girder Bridge on High-Speed Railway

为准确评估高速铁路大跨度钢桁梁桥运营安全性,基于5座大跨度钢桁梁桥运营6~10年后的检测结果,分析其典型病害和病害原因;依据相关规范,以某连续钢桁拱桥为例,测试分析列车荷载作用下桥梁结构的自振频率、振幅、加速度、动应变和动挠度。结果表明:5座大桥典型病害包括钢结构涂层脱落、锈蚀,高强度螺栓断裂、缺失,桥墩墩身裂缝,以及支座临时连接件未拆除、组件锈蚀;病害产生主要原因与桥梁运营荷载、所处环境和施工缺陷有关;在列车荷载作用下,某连续钢桁拱桥结构自振频率、振幅、加速度和动挠度均满足规范要求,动应力增量较小,桥梁结构安全储备较大,运营总体安全;5座大桥仅需进行耐久性处治,包括钢结构维护性涂装、增补高强度螺栓、桥墩裂缝封闭灌浆、解除支座临时约束等。

To accurately evaluate the operation safety of long-span steel truss girder bridges on high-speed railway,the typical deteriorations and causes of deteriorations were analyzed,based on the inspection results of five long-span steel truss girder bridges(including the steel truss arch bridges and steel truss cable-stayed bridges that have been in service for about 6 to 10 years).Counting on the related specifications,a continuous steeltruss arch bridge railway was cited as an example,to test and analyze the natural vibration frequencies,vibration amplitude,acceleration as well as dynamic strain and deflection of the bridge structure under train loads.The results show that the typical deteriorations of the five bridges include the scaling of paint coatings and corrosion of steel structures,fracture and loss of high-strength bolts,pier shaft cracking,the ignored and remained temporary connectors in bearings and the corrosion of members of those temporary connectors.All these deteriorations can be mainly attributed to the live loads on the bridge during the operation period,the environment and construction defects.Under train loads,the natural vibration frequencies,vibration amplitude,acceleration and dynamic deflection of the example bridge can meet the code requirements,with small dynamic stress increment and big safety margin for the bridge structure,suggesting that the overall operation condition is safe.The five bridges need being remedied to improve durability,and the specific treatments incorporate recoating the steel structures,supplementing high-strength bolts,grouting the cracks in pier shafts and releasing the temporary restraints on bearings.