基于TMD的自锚式人行悬索桥人致振动控制研究
Study of pedestrian-induced vibration of self-anchored suspension footbridge based on TMD

现代大跨轻型人行桥很难满足我国现行《城市人行天桥与人行地道技术规范》(CIJ69-95)对人行桥基频不小于3 Hz的要求。对比分析其他国家人行桥舒适度评价标准和规范发现，限制动力响应值法相比频率调整法更适合现代大跨轻型人行桥设计。为了给我国制定人行桥振动舒适度评价标准提供依据，以一座双塔三跨自锚式钢箱梁人行悬索桥为工程背景，建立有限元模型，计算结构动力特性，依据EN03-2007和ISO10137规范确定人行荷载模式，并进行加速度响应分析和舒适度评价。以无阻尼结构调谐质量阻尼器(TMD)最优参数为初始值，优化TMD与主体结构的质量比和频率比，确定合理的减振控制方案。计算结果表明，自锚式人行悬索桥在附加与主梁质量比为1.5%的TMD后人致振动减振率为70.9%~81.7%，可达到相关规范最好舒适度要求。
Modern long span flexible footbridges are very difficult to satisfy the requirement of current Technical Specifications of Urban Pedestrian Overcrossing and Underpass (CIJ69-95). The fundamental frequency of pedestrian bridges cannot be less than 3Hz in this specification. Comparing and analyzing current design criteria and codes for footbridges in other countries, it’s found that the method limiting dynamic response was more reasonable for the design of modern long span flexible footbridges than tuning the natural frequencies of the structure. To provide the evidence for developing the comfort evaluation standards to pedestrian-induced vibration of footbridges, this paper built the finite element model, and calculated the dynamic characteristics of a three-span steel box girder self-anchored suspension footbridge. According to EN03-2007 and ISO10137, the pedestrian load mode, acceleration response and comfort evaluation were analyzed. Taken the optimal parameters of tuned mass damper (TMD) of undamped structure as the initial values, the mass ratio and frequency ratio between TMD and this bridge were optimized and the sound vibration control method was determined. The results show that the pedestrian-induced vibration reduction ratios of this footbridge are from 70.9% to 81.7% after attached the TMD whose mass is only 1.5% of the bridge girder. The vibration response can reach the best comfort requirements of relevant specifications