重载列车引起的大跨度斜拉桥拉索振动研究

采用子结构法研究了重载列车引起的大跨度铁路斜拉桥拉索非线性振动问题。首先基于线性桥梁空间有限元模型,采用车-桥耦合动力学理论计算得到斜拉索锚固点动力响应;然后将该动力响应作为斜拉索端部激励,采用自编的基于CR列式法(Co-rotational Formulation)的拉索非线性动力有限元程序,计算斜拉索非线性动力响应。以荆岳铁路洞庭湖三塔斜拉桥为例,开展了车致斜拉桥拉索振动分析,结果表明:在设计时速范围内,重载列车作用下,斜拉桥索端激励与拉索固有频率两者不存在明显的匹配关系,车致拉索振动响应为一个准静态过程;通过进一步对比不同计算方案,即车-桥耦合振动、移动轴重瞬态分析与移动轴重影响线加载对拉索响应的影响,发现对于大跨度铁路斜拉桥而言,由于车-桥耦合振动效应不显著,采用移动轴重影响线加载方法得到的拉索应力结果具有足够精度。

Analysis of cable vibration of long-span cable-stayed bridge induced by heavy haul train

In order to study the nonlinear vibration of cables of long-span railway cable-stayed bridges caused by heavy haul trains,the substructure method is adopted.Based on the linear bridge space finite element model,the dynamic response of the cable anchorage point is calculated by the bridge coupling dynamics theory.Then the dynamic response is used as excitation of the end of the cable,and the nonlinear dynamic finite element program of the cable based on the CR column method is adopted to calculate the nonlinear dynamic response of the cable.Taking the Dongting Lake three tower cable-stayed bridge of Jingyue railway as an example,the cable vibration analysis of the cable-stayed bridge is carried out.The results show that there is no obvious correlation between the dynamic response of the main beam and the bridge tower of the cable-stayed bridge under the effect of the heavy load train and the vibration response of the cable-stayed cable,and the vibration response of the car induced cable is a quasi-static over time.Through further comparison of the different calculation schemes,namely vehicle bridge coupling vibration method,moving axle load method and static live load method,on cable stress,it is found that for large span railway cable-stayed bridge,the cable stress results obtained by static live load method are of sufficient accuracy because the effect of vehicle bridge coupling vibration is not significant.