景区大跨人行悬索桥涡振特性风洞试验研究

Experimental Study on Vortex-Induced Vibration of Large-Span Pedestrian Suspension Bridge

为掌握大跨人行悬索桥(玻璃桥面)涡振特性,借助主梁节段模型涡振风洞试验,分别研究了风攻角、阻尼比、桥面粗糙度和桥面栏杆设置对主梁涡振性能的影响。结果表明:风攻角由正转负,竖向和扭转涡振振幅均增大,竖向涡振风速锁定区间基本不变,扭转涡振风速锁定区间向低风速区偏移;提高阻尼比对主梁涡振具有明显的抑制作用,且较竖向涡振对扭转涡振振幅的抑制效果更显著,但对二者风速锁定区间均影响不大;降低桥面粗糙度,竖向和扭转涡振振幅均增大,玻璃桥面的采用,使主梁涡振性能变差;桥面栏杆上设置抑流板以及将桥面栏杆间隔封闭,均能明显抑制涡振振幅并一定程度地压缩风速锁定区间,考虑到施工便利性,桥面栏杆间隔封闭更实用。

In order to grasp the vortex-induced vibration characteristics of large-span pedestrian suspension bridge(glass deck),a vortex-induced vibration wind tunnel test was conducted for the girder section model of the bridge,The influence rule of wind attach angle,damping ratio,deck roughness,railing setting on its vortex-induced vibration performance was studied. The results show that with the wind attach angles changing from positive to negative,the amplitude of vertical and torsional vortex-induced vibration increases. Meanwhile,the lockin region of wind speed of vertical vortex-induced vibration is basically unchanged,but the torsional vortex vibration shifts to a low wind speed region. Improving damping ratio can obviously restrain the vortex-induced vibration,and the restrain effect of torsional vortex vibration is more significant,while it has little effect on the lockin region of wind speed. With the decrease of deck roughness,the amplitude of vertical and torsional vortex-induced vibration increases. Therefore,using glass deck can degrade the performance of vortex-induced vibration.Both setting up airflow-suppressing board on railing and closing railing interval can improve the performance of vortex-induced vibration. Considering the construction convenience,closing railing interval is more practical.