方钢管混凝土柱-外环板式组合梁节点抗连续性倒塌性能分析

Progressive collapse performance analysis of concrete-filled square steel tubular column to composite beam with outer ring plate connection

以中柱失效工况下的方钢管混凝土柱-外环板式组合梁节点为研究对象,采用ABAQUS分析其抗连续性倒塌全过程工作机理,计算荷载-位移曲线、节点破坏形态等,分析了楼板在组合节点连续性倒塌过程中的作用,并对影响组合节点抗连续性倒塌性能关键参数进行分析。结果表明:该类组合节点倒塌大致分为弹性阶段、弹塑性阶段、拱效应阶段、塑性阶段、混合机制阶段、悬链线效应阶段。楼板的拱效应可提升节点初期承载力,同时钢筋的拉结作用可以增强节点悬链线效应,但拉结作用的发挥与抗剪连接件有关,因此在设计施工中应重视楼板与钢梁连接的设计,确保其连接可靠,并更好地利用楼板的拱效应与悬链线效应。通过参数分析可知,增加钢梁强度与钢梁翼缘、腹板的厚度可以显著提高组合节点抗连续性倒塌性能。楼板混凝土强度的增加仅提高节点倒塌初期的承载力。

Based on the middle column failure conditions of concrete-filled square steel tubular（ CFST） column to composite beam with outer ring plate connection,the mechanism performance is studied by using ABAQUS software. Loading versus displacement curves and failure modes are obtained. Focus on analysis of slab in composite roles of progressive collapse. The results indicate that the progressive collapse process is divided into elastic stage,elastic plastic stage,arch effect stage,plastic stage,mixed mechanism stage and catenary action stage. The arch effect of the floor increases the bearing capacity of the connection at the initial stage and floor pulling effect enhances the effect of catenary action. However,the floor pulling effects are affected by the connecting. In design and construction,the design of the floor slab and steel beam connections are considerated carefully,ensure that it is connected securely,and use arching effect and the catenary effect of floor better. Through parameter analysis,byincreasing the strength of the steel beam and the thickness of the web and flange,the capacity performance of the composite joints is significantly improved. Increase of concrete floor strength only increases the bearing capacity at the initial stage of collapse.