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为了研究比例阻尼参考振型选取对斜拉桥地震响应分析结果的影响,应用考虑结构阻尼比分布影响的振型应变能比例阻尼理论,选取不同Rayleigh阻尼比参考振型进行了比较分析。根据反应谱的概念提出了一种比例阻尼参考振型选取的重要度指标,应用应变能比例阻尼理论得到振型阻尼比,将其作为已知条件,以杭州湾跨海大桥北航道桥设计方案(斜拉桥)为背景,研究了比例阻尼参考振型选取的重要度指标及其适用性。结果表明:大跨度斜拉桥阻尼比组成复杂,各阶振型的阻尼比差别较大,分布很不均匀,很难利用少数几个参考振型的阻尼比全面反映斜拉桥的阻尼比特性。
In order to study the influence of the reference damping modal on the seismic response analysis of cable-stayed bridges, a comparative analysis of different Rayleigh damping ratio reference vibration modes is made by using the proportional damping theory of mode-strain energy ratio which takes the influence of structural damping ratio distribution into account. According to the concept of response spectrum, an index of importance of reference damping for proportional damping is proposed. The damping ratio of mode shapes is obtained by using the theory of strain energy proportional damping, which is regarded as a known condition. Taking the design of North Channel Bridge of Hangzhou Bay Sea- (Cable-stayed bridge) as the background, the importance index and the applicability of the reference damping mode of proportional damping are studied. The results show that the damping ratio of the long-span cable-stayed bridge is complex, the damping ratios of the vibration modes of the long-span cable-stayed bridges vary greatly and the distribution is very uneven. It is difficult to fully reflect the damping ratio characteristics of cable-stayed bridges with the damping ratio of a few reference vibration modes .