斜拉桥地震响应分析中比例阻尼参考振型的选取

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。

Reference Vibration Shape Selection of Proportional Damping in Seismic Response Analysis of Cable-stayed Bridge

In order to study the influence of reference vibration shape selection of proportional damping on the seismic response analysis results of cable-stayed bridges,using modal strain energy ratio damping theory,different Rayleigh damping reference vibration shape were compared.A significant index of reference vibration shape in proportional damping was proposed based on the concept of response spectrum.On the assumption that the vibration shape damping ratios were known based on strain energy proportional damping theory,the same cable-stayed bridge was used to study the applicability of the significant index for the selection of reference vibration shapes in proportional damping,which supplied criterion and reference to the selection of reference modes of proportional damping in the Northern Channel Bridge of Hangzhou Bay Bridge seismic analysis.Results show that the damping composition of large span cable-stayed bridge is complicated;the vibration shape damping ratios have great differences and their distributions are uneven.It is hard to describe the damping ratio property of cable-stayed bridges by damping ratios of several vibration shapes.