风屏障对大跨度桁架桥风致振动及车辆风载荷的综合影响研究

Comprehensive effect of wind screens on wind-induced vibration of long-span truss bridge and wind loads of vehicles

为探究风屏障对大跨度桁架桥风致振动及车辆风载荷的综合影响,以某公铁两用桁架桥为背景,在XNJD-1号风洞中进行了1∶47.48的缩尺比节段模型试验,测试了无风屏障和设置不同风屏障方案时,车桥系统中车辆及桥梁各自的气动力系数、主梁的颤振临界风速以及主梁的涡振响应。结果表明:大跨度桥梁风屏障增加了车桥系统中主梁的阻力系数,降低了主梁的升力系数、车辆的阻力系数及升力系数。设置风屏障使主梁的颤振临界风速降低明显。风屏障在一定程度上可用作抑制主梁涡振的气动措施。

In order to study the comprehensive effect of wind screens on the wind-induced vibration of long-span truss bridge and the wind loads of vehicles,based on a road-cum-rail truss bridge,a 1：47.48 scale sectional model was tested in the XNJD-1 wind tunnel.The aerodynamic coefficients of the vehicle and the bridge in a vehicle-bridge system, the critical flutter velocity and the vortex-induced vibration response of the main beam were tested without and with different wind screens.The results show that when the wind screen is installed on the long-span bridge,the drag coefficient of the bridge in the vehicle-bridge system increases while the lift coefficient of the bridge decreases.As for the vehicle,the drag coefficient and the lift coefficient both decrease.It is also suggested that the wind screens decrease the critical flutter velocity significantly,and the wind screen could be used as the aerodynamic measure for mitigating a vortex-induced vibration of main beam.