跨海公铁两用桥梁车-桥-风浪流耦合振动研究

Study on coupling vibration of vehicle-bridge-wind-wave-current system of rail-cum-road sea bridge

基于大系统的思想,建立车-桥-风浪流耦合动力系统,包括车辆子系统、桥梁子系统和风浪流耦合场子系统。根据各子系统之间的相互作用力以及车辆子系统与桥梁子系统之间的位移协调关系,建立车-桥-风浪流耦合动力系统的运动方程,并基于分离迭代法提出了车-桥-风浪流耦合动力系统动态响应的求解流程,从而建立跨海公铁两用桥梁车-桥-风浪流耦合动力系统的振动分析方法。以某跨海公铁两用斜拉桥方案为对象进行研究,结果表明:风浪流耦合场同时激励车辆和桥梁的主梁、桥塔及水中基础,与风场单独作用相比,风浪流耦合场能够激发桥梁产生更大幅度的横向和扭转振动,恶化列车运行安全性指标,桥梁主梁在主跨跨中处的横向位移、横向加速度、扭转位移、扭转加速度的均方根分别增大0.8%、23.1%、4.9%和0.5%,在边塔处的相应均方根分别增大204.9%、167.0%、198.7%和314.7%;列车车体加速度、轮轨横向力和轮重减载率分别增大60.9%、7.2%和6.6%。因此,对于跨海公铁两用桥梁,需合理考虑风浪流耦合作用,仅考虑风场单独作用将高估桥梁结构和列车行车的安全性。

Based on the idea of large system,the vehicle-bridge-wind-wave-current coupling dynamic system was established,including a vehicle subsystem,a bridge subsystem and a wind-wave-current coupling field subsystem.An analysis framework of the vehicle-bridge-wind-wave-current coupling dynamic system was proposed.Within this framework,the motion equation of the coupling system was established,based on the interaction forces of three subsystems as well as the displacement compatibility relationship between vehicle subsystem and bridge subsystem,and furthermore,the solution process of dynamic response based on the separation iterative method was proposed.A rail-cum-road cable-stayed sea bridge scheme was studied,and the research results show that the wind-wave-current coupling action can excite the vehicle,girder,pylon and underwater foundation concurrently.Compared to the single wind action,the wind-wave-current coupling action can cause more acute lateral and torsional response of bridge and worsen the train safety in operation.The root-mean-square of lateral displacement,lateral acceleration,torsional displacement and torsional acceleration increase 0.8%,23.1%,4.9%and 0.5%for the girder at the mid-span of main span,respectively,and increase 204.9%,167.0%,198.7%and 314.7%for the girder at the side tower,respectively;The car-body acceleration,the wheel/rail lateral force and wheel unloading rate of vehicle increase 60.9%,7.2%and 6.6%,respectively.Therefore,it is necessary to consider the wind-wave-current coupling action for the rail-cum-road sea bridge,and considering the single wind action may overestimate the safety of the bridge and the vehicle in operation.