带高防抛网边主梁斜拉桥气动性能试验研究

Test study on aerodynamic performance of a side main beam cable-stayed bridge with high anti-throwing net

为研究带高防抛网边主梁斜拉桥的气动稳定性能,以某跨铁路站场边主梁斜拉桥为工程背景,通过节段模型及气弹模型风洞试验综合研究了带高防抛网边主梁斜拉桥的气动稳定性能,并确定了其合理的气动优化措施。利用1∶50比例节段模型风洞试验,测试了各个攻角下主梁的风振响应;在低紊流度流场条件下,通过改变防抛网透风率,对主梁的涡振性能进行优化。设计并制作1∶100比例气弹模型,在不同地表风场类型中进行了风洞试验测试,研究了不同攻角及偏角下全桥气弹模型的涡振性能。风洞试验结果表明:均匀流场中,设置60%透风率的防抛网的节段模型与气弹模型,在最不利3°攻角下,仍发生超过规范限值的竖向涡振。节段模型试验中,在5%紊流风场条件下,主梁断面设置60%透风率的防抛网可以有效抑制涡振,且考虑三维效应的全桥气弹模型与节段模型试验结果相同,无涡振现象发生。

Here,to study aerodynamic stability performance of a side main beam cable-stayed bridge with a high anti-throwing net,taking a certain cross-railway station yard’s side main beam cable-stayed bridge as the engineering background,a segment model and an aeroelastic model wind tunnel tests were conducted to comprehensively study aerodynamic stability performance of a side main beam cable-stayed bridge with a high anti-throwing net,and determine its reasonable aerodynamic optimization measures.Wind tunnel tests were conducted using a 1∶50 scale segmental model to test wind induced vibration responses of main beam at various angles of attack.Under low turbulence flow conditions,vortex induced vibration(VIV)performance of main beam was optimized by changing ventilation rate of anti-throwing net.a 1∶100 scale aeroelastic model was designed and fabricated to conduct wind tunnel tests in different surface wind field types,and study VIV performance of full bridge aeroelastic model at different angles of attack and deflection.Wind tunnel test results showed that in a uniform flow field,segment model and aeroelastic model with a 60%ventilation rate of anti-throwing net still have vertical VIV to exceed the specification limit at the most unfavorable 3°angle of attack;in segment model tests,under the condition of 5%turbulent wind field,anti-throwing net with a 60%ventilation rate on main beam section can effectively suppress VIV,test results of full bridge aeroelastic model considering 3-D effect are the same as those of segment model,no VIV phenomena appear.