摘要
研究FRP约束竖向钢筋搭接节点部分钢筋失效对装配式混凝土框架结构地震易损性的影响。基于连接节点的锚固、搭接试验结果,利用OpenSees有限元分析软件建立考虑部分节点连接钢筋失效的装配式框架结构二维数值模型;采用增量动力分析法(IDA),以PGA-θ_(max)为指标评估了立即使用(IO)、生命安全(LS)、防止倒塌(CP)三种性态的地震易损性,并对比了问题楼层、问题柱数量与位置、失效钢筋比例与分布的影响。结果表明:失效节点的首层效应最显著,在IO、LS和CP性态下平均超越概率分别提高了7.59%、20.32%和62.73%;当问题框架柱占比为50%和75%时,CP性态下的倒塌概率平均增幅为32.75%和49.67%;节点截面内失效钢筋占比为25%、37.5%和50%时,CP性态下的倒塌概率平均增幅为25.48%、46.21%和62.73%;节点截面内失效钢筋的非对称分布导致某一受弯方向有效高度显著削弱时,整体结构倒塌概率进一步放大。首层节点连接缺陷对结构抗震性能影响最为显著,设计时应重点加强首层柱节点及柱截面主受弯方向的连接构造。同时,应建立基于失效钢筋比例与分布模式的施工质量分级控制标准,当单节点内失效钢筋比例超过25%或呈现非对称分布时,需采取修复补强措施。
This study investigates the effects of partial reinforcement failure at FRP-confined vertical bar lap-splice joints on the seismic fragility of prefabricated reinforced concrete(RC)frame structures.Based on anchorage and lap-splice tests of connection joints,two-dimensional numerical models of prefabricated RC frames that explicitly account for partial connection rebar failure were developed in OpenSees.Incremental dynamic analysis(IDA)was conducted,and seismic fragility was evaluated using PGA-θmax as the intensity-response metric for three performance states:immediate occupancy(IO),life safety(LS),and collapse prevention(CP).The influences of the problematic story,the number and location of deficient columns,and the proportion and distribution of failed reinforcement were compared.The results indicate that first-story joint failures govern the response:the average exceedance probabilities at IO,LS,and CP increase by 7.59%,20.32%,and 62.73%,respectively.When 50%and 75%of the frame columns are deficient,the average increase in collapse probability at CP is 32.75%and 49.67%,respectively.When the fraction of failed bars within a joint section is 25%,37.5%,and 50%,the average increase in collapse probability at CP is 25.48%,46.21%,and 62.73%,respectively.Moreover,asymmetric within-section distributions of failed bars that significantly reduce the effective depth in a given bending direction further amplify the overall collapse probability.It is concluded that first-story connection defects have the most pronounced adverse impact on seismic performance;thus,design should prioritize strengthening first-story column joints and the primary bending direction of column sections.In addition,construction quality grading criteria should be established based on the proportion and distribution pattern of failed reinforcement;when the failed reinforcement ratio within a single joint exceeds 25%or exhibits asymmetric distribution,repair and strengthening measures are required.
作者
金峤
崔赛赛
孙丽
JIN Qiao;CUI Saisai;SUN Li(School of Civil Engineering,Shenyang Jianzhu University,Shenyang,China,110168)
出处
《沈阳建筑大学学报(自然科学版)》
北大核心
2026年第2期196-206,共11页
Journal of Shenyang Jianzhu University(Natural Science)
基金
国家自然科学基金项目(52378253)。
关键词
框架结构
连接钢筋失效
FRP约束
增量动力分析
地震易损性分析
frame structures
connection rebar failure
fiber reinforced polymer confinement
incremental dynamic analysis
seismic fragility analysis
