求解建筑结构风致抖振问题的方法分析

Methods for solving wind-induced buffeting problem of civil engineering structures

求解建筑结构风致抖振问题有两种方法:一是新近发展的基于背景和共振分量的Holmes方法,二是传统的适用于求解动力问题的模态迭加法.为分析这两种方法内在的联系和区别,从方法原理和计算过程角度,相互对照两者在求解风致响应和等效风荷载时对背景和共振分量的具体计算方法,并通过主次梁体系屋盖的实例进行对比研究.实例分析发现,对于风致响应,两种方法得到的结果一致,但对于不同的响应类型,模态迭加法需考虑不同的模态阶数;对于等效风荷载,模态迭加法得到的结果是Holmes方法结果的逼近和近似,当模态迭加法采用的模态阶数越高时,两种方法结果之间的差异就越小.

There are two methods for solving wind-induced buffeting problem of civil engineering structures. One is Holmes method based on background and resonant components, mainly developed by Holmes recently; the other is traditional modal decomposition method appropriate for structural dynamic problem. In order to clarify the relationship between these two methods, the basic principle of the methods was described and the methods to obtain the background and resonant components were compared in detail. The beam-supporting roof was taken as example to demonstrate the comparison. As for wind-induced response, agreement was found between the results of the two methods. And different number of modes may be needed to meet the different response when modal decomposition method was used. As for equivalent static wind load, the results of the modal decomposition method were just approximations of those obtained from Holmes method. When higher mode was considered in modal decomposition method, small disparities were observed between the two methods.