基于增量动力分析的梁贯通式支撑钢框架地震易损性研究  

Seismic fragility analysis of beam-through steel braced frames based on IDA method

作　　者：王伟[1,2] 胡书领[1,2] 邹超 WANG Wei;HU Shuling;ZOU Chao(State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;Department of Structural Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程防灾国家实验室,上海200092 [2]同济大学建筑工程系,上海200092

出　　处：《建筑结构学报》2021年第4期42-49,共8页Journal of Building Structures

基　　金：国家自然科学基金项目(51778459,51820105013);土木工程防灾国家重点实验室科研基金项目(SLDRCE19-B-05)。

摘　　要：为了得到梁贯通式支撑钢框架节点刚度及承载力设计方法,基于增量动力分析(IDA)方法,研究了节点性能对多层梁贯通式支撑钢框架地震易损性的影响,得到了不同节点刚度和承载力设置下四种模型(刚接、全强度半刚接、半强度半刚接和铰接模型)的易损性曲线,定量评价了各模型超越各极限状态的概率和倒塌储备系数。研究结果表明:无论节点刚度和承载力如何设置,在8度罕遇地震(地面峰值加速度为0.4g)作用下,该结构发生倒塌的概率均小于1%,能够满足规范规定的"大震不倒"的要求。当节点刚度达到4倍相邻柱线刚度时,无论节点设置为柱端达到全截面屈服或部分屈服,结构在罕遇地震下的地震易损性相差不大,倒塌储备系数均高于FEMA P695中的建议水平;而铰接结构模型的抗倒塌能力则明显低于其他三种结构模型。基于分析结果,建议梁贯通支撑钢框架梁柱节点刚度应不小于相邻柱线刚度的4倍,节点承载力需不小于柱端全截面屈服弯矩的50%。Based on incremental dynamic analysis(IDA), the influence of beam-to-column connection’s performance on the seismic fragility of beam-through steel braced frames was investigated to obtain the stiffness and strength demand for designing the beam-to-column connections. The seismic fragility curves were derived for four comparative models, including the rigid model, full strength and semi-rigid model, partial strength and semi-rigid model, and regular pinned model. The exceeding probability of different limit states and collapse margin ratios of the four models were quantitatively evaluated. The analysis results indicate that regardless of the stiffness and strength of the connection, the collapse probability of the representative structure is less than 1%, which can meet the collapse resistance requirement under 8-degree rare earthquakes of which the peak ground acceleration(PGA) is equal to 0.4g. When the connection stiffness is more or equal to four times of the line stiffness of the adjacent columns, the connection strength has negligible influence on the seismic fragility of the representative structures under rare earthquakes. Moreover, the collapse margin ratios of the considered structures are all larger than the recommended values as in FEMA P695. In contrast, the collapse resistance capacity of the regular pinned model is much lower than that of other three models. Based on the analysis results, it is recommended that the connection stiffness of a beam-through steel braced frame should be more than 4 times of the line stiffness of the adjacent columns, and the connection strength should be not less than 50% of the full plastic flexural capacity of the column.

关 键 词：支撑钢框架 梁贯通 增量动力分析 节点刚度 节点承载力 地震易损性分析 倒塌储备系数 

分 类 号：TU391[建筑科学—结构工程] TU311.41