跳车冲击过程中的桥梁动态位移响应分析

Analysis of Dynamic Displacement Response of Bridges under Vehicle's Impact

以1/4简构车辆和含阻尼简支梁桥为对象,建立可描述跳车冲击过程的车桥耦合振动分析模型。采用Newmark-β积分法获得车桥耦合系统振动响应的数值解。在不同高度、不同跳车位置以及不同车速等工况下,重点讨论跳车冲击过程中桥梁竖向动态位移响应的表现特征。数值分析表明:在文中考虑的跳车冲击工况下,桥梁竖向动态位移存在显著差异;不同跳车高度对动态位移峰值影响很小;不同跳车位置时的竖向动态位移表现各有不同,靠近跨中处,在桥梁前半跨发生跳车冲击对桥梁竖向动态位移值的影响明显大于后半跨,远离跨中处,桥梁前半跨动态位移值与后半跨相近,且最大竖向动态位移表现出滞后特征;不同车速对桥梁竖向位移值影响不同。

With a quarter of the simplified vehicle and the damped simply supported girder bridge as the object,the vehicle-bridge coupling dynamic model is established for analyzing the impact process between the vehicle and the bridge.The numerical solution of vehicle-bridge coupling vibration response is obtained by using Newmark-βintegral method.The displacement responses of the vehicles under the conditions of different impact heights,impact positions on the bridge and two vehicles impacts are derived.Characteristics of the vertical dynamic displacement of the bridge under the impact of the vehicle jumping are discussed.The numerical analysis shows that the different heights of the vehicle jolting have little influences on the peak value of the vertical displacement response.The vertical dynamic displacement of the bridge is different when the vehicle jumps at different positions.Near the middle of the span,the influence of the vehicle jumping on the vertical displacement of the front half-span is much larger than that of the rear half-span.While for the position far away from the middle of the span,the dynamic displacement value of the front half-span of the bridge is close to that of the rear half span.The maximum vertical dynamic displacement of the bridge demonstrates hysteresis characteristics.The influence of different speed on the vertical displacement of bridge is different.