考虑预应力筋断裂失效的自复位支撑钢框架结构抗震性能与风险评估  

Seismic performance and risk assessment of self-centering steel braced frames considering failure of prestressed tendons

作　　者：平奕炜 方成 陈以一[1,2] PING Yiwei;FANG Cheng;CHEN Yiyi(College of Civil Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory for Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《建筑结构学报》2022年第7期1-10,20,共11页Journal of Building Structures

基　　金：国家自然科学基金项目(52078359,51778456,51820105013)。

摘　　要：为研究自复位支撑中预应力筋发生断裂失效对结构整体抗震性能的影响,以形状记忆合金(SMA)拉索自复位支撑结构为研究对象。通过理论分析典型单核和双核自复位支撑的失效机理,发现双核自复位支撑在提升变形能力的同时存在瞬时连锁失效风险。为此,设计了不考虑预应力筋失效的理想自复位支撑框架、考虑预应力筋失效的单核、双核自复位支撑框架以及SMA自复位支撑框架等4个原型结构模型。考虑预应力筋断裂失效的随机性分布特征,在远场和近场地震作用下对框架进行非线性时程分析;进一步采用IDA方法对框架进行倒塌及残余变形易损性分析,并结合场地特征进行风险评估。分析结果表明:考虑预应力筋的断裂失效会显著增加框架倒塌的风险,在服役期风险评估中,其倒塌概率是理想情况下的5倍左右,残余变形超越概率最高为理想情况下的6倍;SMA自复位支撑具有更大的变形能力以及额外的耗能能力,在抗倒塌和抑制残余变形方面表现更为良好。This paper comprehensively discussed the performance of self-centering steel braced frames suffering failure of prestressed tendons.The performance of the structures with shape memory alloy(SMA)cable-based self-centering braces was also examined.Through theoretical analysis,the fundamental mechanism of tendon failure of typical single core and dual core self-centering braces is first introduced,and it is found that the dual core self-centering brace may suffer more abrupt failure,although its deformability is improved.Four prototype structures were designed,i.e.,an ideal self-centering braced frame without considering the failure of prestressed tendons,single core and dual core self-centering braced frames considering the failure of prestressed tendons,as well as an SMA-based self-centering braced frame.Considering a random distribution of tendon failure strain,nonlinear time history analysis was carried out on the frames under far-field and near-field earthquakes.Furthermore,the collapse and residual deformation fragilities of the frames were evaluated,and risk assessment was conducted according to the site characteristics.The results show that the risk of collapse is significantly increased when considering the failure of the prestressed tendons.During their service life,the collapse probability is about five times that of the ideal case and the probability of exceedance of residual deformation is up to six times that of the ideal case when tendon failure is considered.The SMA self-centering brace has enhanced deformation capacity and enables additional energy dissipation,and hence performs better in mitigating both the risk of collapse and residual deformation.

关 键 词：自复位支撑 SMA 预应力筋失效 易损性分析 风险评估 倒塌性能 残余变形 

分 类 号：TU352.1[建筑科学—结构工程] TU311.41