（1 杭州铁木辛柯建筑结构设计事务所有限公司， 杭州 311215； 2 浙江大学土木工程系， 杭州 310058；3 北汇绿建集团有限公司， 菏泽 274000）

［摘要］通过对ETABS软件进行二次开发，给出《钢结构设计标准》(GB 50017—2017)直接分析设计法在ETABS软件中的实现方式。在此基础上，以山东某高层住宅项目采用的隐式框架-支撑结构体系为例，采用考虑结构整体初始几何缺陷和构件初始缺陷的动力弹塑性分析方法，分析该结构在大震作用下的动力响应和两种缺陷对结构抗震性能的影响。分析结果表明：罕遇地震作用下，有无考虑缺陷和二阶效应时得到的结构最大层间位移角均未超过1/50限值，支撑起到了第一道抗震防线的作用，框架柱保持弹性，满足“强框架，弱支撑”的设计要求。考虑缺陷和二阶效应会使结构最大层间位移角有所增加，根据结构二阶效应系数和延性系数可近似估算二阶效应对最大层间位移角的放大系数；对于高延性结构，在进行动力弹塑性分析时，应考虑缺陷和二阶效应对结构抗震性能的影响。

［关键词］结构整体初始几何缺陷； 构件初始缺陷； 直接分析设计法； 隐式框架； 动力弹塑性分析； 二阶效应

中图分类号：TU398-2文献标识码：A文章编号：1002-848X(2020)03-0005-08

Dynamic elasto-plastic second-order effects analysis of hidden frame-brace structure by considering geometric imperfections of overall structure and member

Fu Bo1， Tong Genshu2， Hong Qi3， Wang Yanchao1

（1 TongMSK Hangzhou Steel Structure Design Co., Ltd., Hangzhou 311215, China; 2 Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China; 3 Beihui Green Construction Group Co., Ltd., Heze 274000, China）

Abstract:Direct analysis method of design which is given by Standard for design of steel structure (GB 50017—2017) was implemented by the secondary development of ETABS. On this basis, the hidden frame-brace structure system of a high-rise apartment building in Shandong was taken as an example, the dynamic elasto-plastic analysis method considering initial geometric imperfections of overall structure and member initial imperfections were adopted to analyze the dynamic response of the structure under rare earthquake and the effects of the two  imperfections on the seismic performance of the structure. The results show that the maximum drift ratios are not more than 1/50 limit when  imperfections and second-order effects are considered or not. The brace can serve as the first seismic line of the structure and the frame columns remain elastic. The design requirement of "strong frame-weak brace" is realized. The maximum drift ratio is amplified by the existence of inperfections and second-order effects. The second-order effects coefficient and ductility coefficient of structure can be used to compute the amplification factor of the maximum drift ratio approximately. For high ductility structures, the imperfections and second-order effects should be considered in dynamic elasto-plastic analysis.

Keywords:initial geometric imperfections of overall structure; member initial imperfections; direct analysis method of design; hidden frame; dynamic elasto-plastic analysis; second-order effects