悬索桥吊杆风致内共振及减振措施初探  

Wind Induced Internal Resonance and the Control Method of Suspension Bridge Hangers

作　　者：张志田[1] 吴肖波 葛耀君[2] 陈政清[1] 

机构地区：[1]湖南大学风工程试验研究中心,湖南长沙410082 [2]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《湖南大学学报（自然科学版）》2016年第1期11-19,共9页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51178182;51578233)~~

摘　　要：基于现场观测,对特大跨度悬索桥吊杆风致振动现象进行了定性分析,排除了尾流驰振、涡激共振以及风雨激振的可能性.通过数值模拟和理论分析,表明这是一种主缆抖振引起的吊杆共振现象.随机风场激起主缆的随机抖振,而主缆的抖振含有丰富的模态成份,当吊杆的自振频率与具有一定抖振能量的主缆模态的频率充分接近时会激发吊杆的共振.因此,从来流紊流风场中获得能量的是主缆而非吊杆自身.由于与主缆的模态质量相比,一根或几根吊杆的模态质量很小,因此吊杆大幅振动吸收的能量并不会对主缆的振动带来实质性的影响,从而可形成一个相对稳定的能量供给机制.此外,在主缆上加设TMD抑制主缆在吊杆自然频率附近的振动,对吊杆风振有明显的抑制效果.The mechanism of wind-induced oscillation of hangers in a long-span suspension bridge was investigated qualitatively on the basis of field observations, and the possibility of wake galloping, or vortex-induced resonance, or wind-rain-induced oscillation was excluded by reasoning. Numerical simulation and theoretical analysis reveal that this is a kind of resonance induced by the buffeting of main cables. Stochastic wind fields excite the stochastic responses of the main cables, which are abundant in a wide range of modal components, and the resonance occurs when the natural frequency of a hanger is adequately close to one of the main cable＇s natural frequencies that possess enough energy. Hence, it is not the hangers themselves but the main cables that are responsible for the energy absorbing from the turbulence. Compared with the modal mass of a main cable, the mass of one hanger is too small to pose substantial effects on the oscillation of the main cable, and therefore, a steady supply of energy from the main cable to the hangers can be formed. Furthermore, TMD mounted on the main cables can suppress the wind-induced vibration of cables at the natural frequency of hangers, which results in the significant reduction of the vibration of the hangers.

关 键 词：悬索桥 吊杆 主缆 抖振 共振 调质阻尼器 

分 类 号：U448.25[建筑科学—桥梁与隧道工程]