大跨度悬索桥吊索风致振动多重调谐阻尼减振技术研究

Multiple tuned damping technology for suspension cable WIV of long-span suspension bridge

为了控制大跨度悬索桥的吊索风致振动,提出了基于多重调谐质量阻尼器(multiple tuned mass dampers, MTMD)的阻尼减振技术方案,并通过理论分析进行参数优化和设计。研究南沙大桥两座主航道悬索桥吊索实际风致振动响应,分析其频谱特征和振动特性,确定振动控制的目标;建立吊索-MTMD分析模型,优化适用于吊索多模态控制的MTMD阻尼比、频率分布、安装位置、模态参与系数等参数,结果表明:不同于单一频率控制时的优化理论,用于吊索多模态控制的MTMD阻尼比提高为10%,扩展其振动控制的频率范围;通过考虑振型参与系数,优选4个分布主频:13.5 Hz和18.0 Hz安装在位置比为2.9%处,6.5 Hz和9.5 Hz安装在位置比为6.5%处,实现对吊索5~20 Hz风致振动的多模态控制;不同吊索在索力、型号和受控频率范围内,MTMD的设计参数可以采取统一设计方案。

Here, to control wind-induced vibration(WIV) of suspension cables of long-span suspension bridge, a damping technology scheme based on multiple tuned mass dampers(MTMD) was proposed, and MTMD parameters were optimized and designed through theoretical analysis. Actual WIV responses of suspension cables of two main waterway suspension bridges of Nansha Bridge were studied to analyze their frequency spectrum characteristics and vibration characteristics, determine vibration control objectives, and establish the suspension cables-MTMD analysis model. MTMD damping ratio, frequency distribution, installation position, modal participation coefficient and other parameters applicable to multi-mode control of suspension cables were optimized. The results showed that being different from the optimization theory of single frequency control, MTMD damping ratio used for multi-mode control of suspension cables is increased to 10% to expand frequency range of its vibration control;by considering participation coefficient of vibration mode, 4 distributed dominant frequencies are chosen, they are13.5 Hz and 18 Hz installed at the position ratio of 2.9% as well as 6.5 Hz and 9.5 Hz installed at the position ratio of 6.5% to realize multi-mode control of suspension cables within the range of 5-20 Hz WIV;within ranges of cable force, type and controlled frequency of different suspension cables, designing parameters of MTMD can adopt a unified design scheme.