吊索断裂状态下公铁两用悬索桥及桥上列车动力响应研究

Investigation on the dynamic responses of a road-rail suspension bridge and the trains on bridge in case of suspender fracture

为研究大跨度公铁两用悬索桥在列车作用时吊索断裂状态下的动力响应,开发针对柔性结构断索分析的非线性有限元动力算法并验证了算法的合理性。以实际大跨度公铁两用悬索桥为研究对象建立了全桥3D计算模型,计算吊索突然断裂时全桥结构的动力响应;研究在列车-桥梁耦合动力作用下,不同突然断索工况发生时,桥梁结构与桥上行驶列车的动力响应。研究结果表明:大跨度公铁两用悬索桥通常具有较大安全冗余,跨中位置单侧3根以下吊索断裂造成的冲击荷载对桥梁结构的安全性影响较小;当列车在桥上行驶时,若突然发生单根吊索断裂,会导致列车竖向加速度响应发生明显变化,但加速度值在安全范围内;单根吊索断裂后,桥梁可保持列车通行。研究结果可为分析与评估公铁两用悬索桥断索影响提供理论指导。

In order to investigate the dynamic response of a long-span road-rail suspension bridge under the action of a running train in case of suspender fracture,a nonlinear finite element dynamic algorithm for the cable fracture analysis of flexible structures was developed,and the rationality of the algorithm was verified.A real long-span road-rail suspension bridge was taken as the research object,and a 3D calculation model of the whole bridge was established.The dynamic response of the whole bridge structure under the sudden fracture of suspenders was calculated.The dynamic responses of the bridge structure and the train on the bridge were studied in different conditions of suspender fracture under the train-bridge coupled dynamic action.The results show that the long-span road-rail suspension bridge usually has large safety redundancy,and the impact load caused by the fracture of less than 3 suspenders on one side of the middle span of the suspension bridge has little influence on the safety of the bridge structure.When the train is running on the bridge,the vertical acceleration response of the train will change obviously if a single cable fractures suddenly,but the acceleration is still within the safe range.The fracture of a single suspender has little effect on the stiffness of the bridge structure,and the train can be kept running on the bridge.The results provide a theoretical guidance for the analysis and evaluation of the impact of suspender fracture on road-rail suspension bridges.