角柱失效下不等跨RC空间梁-柱子结构抗连续倒塌机理研究  

Load resisting mechanism of RC spatial beam-column substructures with unequal spans in the loss of a corner column scenario

作　　者：李治 薛天琦 原小兰 张毅[2] 钱凯 LI Zhi;XUE Tianqi;YUAN Xiaolan;ZHANG Yi;QIAN Kai(Guangxi Key Laboratory of New Energy and Building Energy Saving,Guilin 541004,China;College of Civil Engineering and Architecture,Guilin University of Technology,Guilin 541004,China)

机构地区：[1]广西建筑新能源与节能重点实验室,广西桂林541004 [2]桂林理工大学土木建筑工程学院,广西桂林541004

出　　处：《振动与冲击》2023年第6期115-125,179,共12页Journal of Vibration and Shock

基　　金：广西科技基地和人才专项(2021AC19076);广西自然科学基金(2021JJB160175,2021GXNSFFA196001);国家自然科学基金优秀青年基金(52022024);广西建筑新能源与节能重点实验室开发基金(桂科能22-J-21-4);广西中青年科研基础能力提升项目(2021KY0254)。

摘　　要：本文通过角柱失效下钢筋混凝土(reinforced concrete,RC)空间梁-柱子结构的Pushdown加载试验及其精细化有限元模型,对不等跨RC空间梁-柱子结构在角柱失效工况下的抗连续倒塌性能进行研究。基于所建立的有限元模型对不等跨RC空间梁-柱子结构的抗力机制等进行更深入的分析,探究了角柱上部水平约束、角柱节点配箍率和空间效应对不等跨RC空间梁-柱子结构抗连续倒塌性能的影响。研究结果表明,角柱失效工况下的不等跨RC空间梁-柱子结构不能有效发展悬链线机制而主要依靠梁机制抵抗倒塌,且空腹机制抗力的贡献不可忽略。角柱上部水平约束的增强,会提高第一峰值荷载,但是同时会导致角柱节点承受更高的剪应力从而提早发生剪切破坏。角柱节点配置一定量箍筋后会延迟和减轻角柱节点发生剪切破坏,从而提高结构的抗连续倒塌能力。对于角柱失效工况,空间效应不能通过简单叠加两个方向的平面框架抗力进行计算,因为空间效应三维剪应力作用会加速角柱节点发生剪切破坏。Pushdown loading tests were carried out on reinforced concrete(RC)spatial beam-column substructures in the loss of a column scenario and a refined finite element(FE)model was established to study the progressive collapse resistance performance of RC spatial beam-column substructures with unequal spans.The influences of horizontal constraints on the top of the corner column,transverse reinforcement ratio at corner joint,and spatial action on the progressive collapse resistance of the substructures were analyzed.The results indicate that for the RC spatial beam-column structure under the loss of a corner column,the structure cannot develop effective catenary action and the collapse resistance mainly relies on the beam action.It should be noted that the contribution of Vierendeel action cannot be ignored.Increasing the horizontal constraints at the upper part of the corner column,the first peak load of the substructures will increase.However,the corner column joint may suffer greater shear stress and be prone to cause shear failure.Installing an amount of transverse reinforcement at the corner joint can delay or mitigate the shear failure of the corner joint.Thus,the progressive collapse resistance capacity of the substructures can be upgraded.Moreover,for the case of corner column failure,the spatial effects can not be taken as a simple summation of the load resistance of the plain frame in two directions,as the spatial effects may aggravate the shear failure of the corner joint.

关 键 词：钢筋混凝土(RC)空间结构 有限元分析 空腹效应 空间效应 连续倒塌 

分 类 号：TU375.4[建筑科学—结构工程]