斜拉桥断索危险性分析

Hazard Analysis of Cable-Stayed Bridges due to Cable Fault

拉索锈蚀甚至断丝是斜拉桥较为常见的病害,其隐蔽性强且具有较大的危险性,是斜拉桥危险性分析的重要部分。结合某斜拉桥的实际工程情况,从结构力学特性及桥梁所面临的危险出发,利用Midas有限元分析软件对桥梁进行建模,系统分析桥梁全寿命过程中所面临的危险、各项危险发生的概率及危险所导致的严重后果。通过对断索状况的模拟,总结出拉索断裂对主梁线形及索力的影响:局部斜拉索的断裂会使主梁下挠增大、临近拉索增大;较长拉索断裂对主梁线形的影响较大,而其引起的周围拉索的索力增量较小。

The cable which rusts or even breaks is a relatively common disease of cable-stayed bridges.It is hard to be observed and has a high fatalness.So the cable is an important part of the hazard analysis of a cable-stayed bridge.Finite element software Midas is applied to establish a model in terms of the structural and mechanical properties of the cables and the dangers the bridges will face with by taking a concrete cable-stayed bridge as an example.The hazard occurring at each stage of the bridge life-cycle,the probability of various hazards and the serious consequence caused by the hazard are systematically analysed.The impacts of cable fault on the main girder geometry and cable force are summarized by simulating cable fault.The fracture of local stayed-cables can make girder deflection increase and nearby cable force increase.The fracture of a long cable will have a bigger impact on the line shape of girder,and gives rise to a smaller increment in the nearby cable force.