斜拉桥拉索风雨振控制的智能阻尼技术

CONTROL OF WIND-RAIN-INDUCED VIBRATION OF STAY CABLES ON CABLE-STAYED BRIDGE USING SMART DAMPING

洞庭湖大桥自建成通车以来已发生多次严重风雨振 ,必须采取有效的振动控制措施。本文应用磁流变阻尼器对该桥风雨振控制进行了仿真和现场试验研究 ,得到了拉索 -阻尼器系统模态阻尼比随阻尼器输入电压的变化关系 ,显示磁流变阻尼器能提供足够的可变阻尼对拉索进行智能控制 ,在实际风雨振时的现场观测结果显示磁流变阻尼器对风雨振具有很好的减振效果 ,实测的加速度响应表明安装阻尼器拉索的加速度响应仅为未加阻尼器拉索的 1/ 2 0～ 30。洞庭湖大桥已计划全桥安装磁流变阻尼器 。

Severe wind-rain-induced vibration was observed many times since opening to traffic on Dongting Lake Bridge,and countermeasure must be taken as soon as possible.Numerical simulation and field test of vibration mitigation of stay cable using magneto-rheological(MR) damper are implemented,and relationship of first three modal damping ratios of cable-MR damper system versus voltage input to MR damper is obtained.Results show that smart control of stay cable vibration will be feasible with enough large and variable damping supplied by MR damper.Acceleration responses indicate that amplitude of acceleration responses of cable with dampers decrease 20-30 times by contrast to the one without dampers.A total implementation of MR damper on Dongting Lake Bridge is being planed,which will be the first project using MR damper to mitigate wind-rain-induced vibration.