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本文对随机振动理论振型分解方法进行了讨论。借助于有限带宽白噪声谱,论证了结构响应中忽略振型交叉项作用的条件不仅与结构阻尼比、频率差值有关,更主要是与结构的激励谱形式有关。由于Davenport风速谱的特点,对许多土木工程结构都存在着准静态效应,结构风振响应中振型交叉项的作用要比对应高振型的作用大,SRSS法不能适用。如果同时考虑两者影响,结果表明:高耸结构的鞭梢效应是不存在的。为了反映高耸结构风振响应准静态效应的范围和程度以及便于工程实际使用,本文给出了风振修正系数的概念和实用表格,同时还给出了两个截止准则。
This paper discusses the method of vibration decomposition of random vibration theory. With the aid of the limited-bandwidth white noise spectrum, it is demonstrated that the condition of neglecting the mode cross term in the structural response is not only related to the structural damping ratio and frequency difference, but also mainly related to the structure of the excitation spectrum form. Due to the characteristics of the Davenport wind speed spectrum, there are quasi-static effects on many civil engineering structures. The effect of the mode-crossing term in the structural wind-induced vibration response is greater than that of the corresponding high-vibration model, and the SRSS method cannot be applied. If both effects are taken into account, the results show that the whiplash effect of high-rise structures does not exist. In order to reflect the scope and degree of the quasi-static effect of wind-induced vibration in tall buildings and to facilitate the practical use of engineering, the concept and practical table of wind-induced vibration correction coefficients are given in this paper. Two cut-off criteria are also given.