单斜面索拱支承曲梁人行桥人致振动控制研究

进行了一种单斜面索拱支承曲梁人行桥的人致振动控制研究。在人行桥的初始状态及静动力特性基础上,模拟了随机人群荷载作用下人行桥的振动响应,参数化地研究了调谐质量阻尼器(Tuned Mass Damper,TMD)的减振作用,考虑了TMD不同质量比、刚度、阻尼参数以及布置方式的影响。在TMD装置安装前后对人行桥进行实地动力测试,测试了结构减振前后的模态特性以及在单人、多人和人群荷载工况下的振动响应,讨论了TMD装置对该类型人行桥的减振效果。结果表明:减振后结构关键模态阻尼增大为减振前的4.14倍;单人步行和跑动工况下,通过设置TMD,结构加速度峰值下降31.1%～55.9%,加速度均方根下降36.4%～52.0%;多种人群步行工况下,结构竖向加速度峰值最大为0.41 m/s~2。研究结果表明单斜面索拱支承曲梁人行桥刚度较柔,TMD对控制该类型人行桥结构人致振动具有很好的效果。

Human-induced vibration control of curved beam footbridge with single inclined cable arch

Human-induced vibration control of a curved beam footbridge with single inclined cable arch was studied. Based on the shape finding and static/dynamic analysis of the footbridge, the vibration response of the footbridge under stochastic crowd load was simulated. The effect on controlling vibration through tuned mass dampers (TMDs) was studied parametrically, considering effects of mass ratio, stiffness, damping parameters and layout modes. The dynamic field measurement of the footbridge was carried out with and without TMDs. The modal characteristics and vibration response under single-pedestrian, multi-pedestrian and crowd loads were tested. The performance upgrading for vibration control with TMDs on the footbridge was evaluated. The results show that the key modal damping of the structure with TMDs was 4.59 times as much as that without TMDs; the peak acceleration of the structure decreased 31.1%~55.9% and the acceleration root mean square (RMS) value decreased 36.4%~52.0% under single person walking and running conditions; the vertical acceleration peak of the structure reduced to 0.41m/s2 under various crowd load conditions. The research results show that this kind of curved beam footbridge supported with single inclined cable arch is flexible and human-induced vibration is hard to control by increasing the structure stiffness. By setting TMDs gives a good performance on human induced vibration control on such flexible footbridge.