空间结构主振型遴选的拓展阈值法  

Extended Threshold Value Method in Dominant Mode Selection of Spatial Structures

作　　者：曲扬 罗永峰[2] 程建军[1] 马怀章 彭影星 李佳鹏[1] QU Yang;LUO Yongfeng;CHENG Jianjun;MA Huaizhang;PENG Yingxing;LI Jiapeng(The Third Construction Co.,Ltd.of China Construction Eighth Engineering Division,Nanjing 210046,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]中建八局第三建设有限公司,南京210046 [2]同济大学土木工程学院,上海200092

出　　处：《建筑钢结构进展》2022年第3期90-98,共9页Progress in Steel Building Structures

基　　金：国家自然科学基金(51378379)。

摘　　要：空间结构的主振型遴选准确与否直接影响着振型叠加法的计算效率。以现有阈值法的基本假定作为切入点,揭示了动力功和静力功均为外力功的本质,指出采用常幅阶跃荷载作为外部激励存在局限性,且现有理论框架的基本假定与实际偏差较大,据此论证了该方法在理论上的不完备性;通过理论推导,将阈值法拓展至与实际地震动输入更具关联性的简谐激励情形,能够同时考虑动力响应和静力响应,避免了不合理的基本假定,并且详细论述了在具有实际意义的共振情况下阈值法的适用性,据此提出了拓展阈值法。算例分析表明,拓展阈值法能够将计算误差控制在10%以内,主振型阶数相比于规范法得到的阶数平均减少了73.8%,相比于现有阈值法得到的阶数平均减少了56.5%,计算稳定且高效。The calculation efficiency of modal superposition method highly depends on whether the dominant modes of a spatial structure are selected validly. The fundamental assumptions of the existing threshold value methods are taken as the breakthrough point and the dynamic work and static work are proved to be external force work. The flaw of constantamplitude stepped load used in the existing method are discussed,along with the considerable deviation from the fundamental assumption therein pointed out. Then the theoretical incompleteness of the existing method is revealed. To address this issue,the threshold value method is extended to the harmonic excitation,which is more relevant to the actual earthquake excitation. Taking both dynamic and static responses into account,the unreasonable assumption is avoided.More practically,the serviceability of the extended method in resonant condition is demonstrated. Therefore,the extended threshold value method is proposed in this paper. Through an example comparison,the extended method is able to obtain a satisfying result with errors below 10%,and simplify the dominant modes which is 73.8% less than those by the code method,and 56.5% less than those by the existing method. The new method is more stable and efficient.

关 键 词：空间结构 主振型 抗震分析 阈值法 简谐激励 

分 类 号：TU393.3[建筑科学—结构工程]