大跨度铁路悬索桥风—车—桥耦合动力分析

Analysis on Wind-Vehicle-Bridge Dynamic Interaction for Long-Span Railway Suspension Bridge

悬索桥虽跨越能力大但刚度较弱,在列车与风荷载的共同作用下易产生较大振动,影响桥上行车安全。为研究风荷载作用下列车通过铁路悬索桥时的车辆与桥梁动力响应及安全性,以轮轨密贴理论定义竖向轮轨作用力,以简化的Kalker蠕滑理论定义横向轮轨作用力,以静风力及抖振风力模拟作用在车辆和桥梁上的风荷载,建立简化的大跨度铁路悬索桥的风—车—桥耦合动力学模型,并给出基于系统间积分的风—车—桥迭代算法。运用该方法对强风条件下列车通过跨度(52+800+800+52)m悬索桥的行车安全性分析表明,系统间迭代算法具有较高的计算效率,仅经过几次迭代即可得到精度较高的计算结果;该大跨度悬索桥在桥面平均风速为25m.s-1时,桥梁跨中竖向动位移较无风状态变化不大,而桥梁跨中竖向加速度及桥跨、桥塔横向动位移和加速度响应则较无风状态有大幅度增加,可见,动风荷载对风—车—桥系统的振动起到控制作用。

The suspension bridge has longer span but smaller stiffness. It may vibrate obviously under the joint loads of vehicle and wind, which affects the running safety of the passing trains. In order to study the dynamic responses of vehicle and bridge as well as the safety factors for train passing through railway suspension bridge under wind load, the simplified dynamic interaction model of wind-vehicle-bridge for longspan railway suspension bridge is established. In which the corresponding assumption is used to define vertical wheel-rail interaction force, the simplified Kalker creep theory is used to define lateral wheel-rail in- teraction force, the static and turbulent wind forces are used to define the wind loads on both the bridge and the train, and the inter-system integral based wind-vehicle-bridge iterative algorithm is proposed. The method is adopted to analyze the running safety of a train passing a （52-＋-800＋800＋52） m suspension bridge under strong wind. It is found that the inter-system iterative algorithm has better computational efficiency, and the result with higher accuracy can be obtained by only a few iteration steps. There is little change in the vertical dynamic displacement of the mid-span of long-span suspension bridge under no wind and with the average wind speed of 25 m .s-1. However, there is a substantial increase in the vertical acceleration of mid-span, the lateral dynamic displacement of bridge span and bridge tower compared with that under no wind condition. It can be concluded that the dynamic wind load has a dominant effect on the vibration of wind-vehicle-bridge dynamic interaction system.