大跨钢箱梁人行桥振动响应分析与MTMD减振控制

Vibration Response Analysis and MTMD Damping Control of A Long-span Steel Box Girder Footbridge

人行桥的自振频率与行人步频接近时,容易发生人桥共振,本文以一频率处于行人步频范围内的大跨钢箱梁人行桥为例,考虑了随机行走、结伴行走和跳跃等11种荷载工况,研究了各工况人行荷载激励下人行桥的竖向振动响应,并针对不满足舒适度要求的工况,采用多调谐质量阻尼器(multiple tuned mass damper简称MTMD)对人行桥进行减振控制。结果表明,人行桥在无控状况下产生了较大的振动响应,其竖向加速度超过舒适度限值要求,而当在人行桥加装MTMD系统后,其振动响应大幅降低,减振效果达到70%以上,实现了人行桥在人行荷载激励下的舒适度控制要求。

When the natural frequency of a footbridge is close to the frequency of pedestrians, the resonance between pedestrians and bridge could be induced by pedestrian loading. Based on the fundamental frequency of a long-span steel box girder footbridge lower than the frequency of pedestrians, this paper considered 11 kinds of load conditions, such as random walking, walking together and jumping together. Besides, the damping technique with multiple tuned mass dampers was used to meet comfort requirements of pedestrians. The results show that the acceleration response of the footbridge without multiple tuned mass dampers exceeded the limit of comfort. However, the acceleration response is greatly reduced after equipping multiple tuned mass dampers, and the damping effect is remarkable, so that the vibration comfort of the footbridge can be met.