翼缘削弱对钢管混凝土外加强环节点受力性能的改善  

Mechanical behavior improvement for concrete filled steel tubular exterior stiffener ring connections with reduced beam flange

作　　者：李成玉[1] 郭耀杰[2] 罗冽[3] 

机构地区：[1]武汉科技大学,湖北武汉430070 [2]武汉大学,湖北武汉430072 [3]香港大学

出　　处：《土木工程学报》2010年第12期21-27,共7页China Civil Engineering Journal

基　　金：湖北省自然科学基金(2006ABA291);武汉科技大学科研启动资金

摘　　要：对加强环式节点进行低周反复加载非线性模拟分析,发现在反复荷载作用初期,环板就出现贯穿的塑性带;通过节点域柱壁滞回曲线与梁端滞回曲线的对比,表明节点滞回曲线主要由柱壁变形而非梁端塑性变形所贡献。为了改变这一不利特征,对钢梁翼缘进行定向削弱,模拟分析发现,节点受力情况得到明显改善:①环板上应力分布得到明显缓和,转角处的应力集中程度明显降低;②通过改变环板尺寸或者翼缘削弱程度可以保证塑性铰先出现在梁根部而不是环面上;③在弹性受力阶段节点刚度没有下降;④在反复荷载作用下,节点域变形很小,环面上的塑性扩展不明显。由此可见,通过翼缘削弱可以明显改善外加强环式节点的受力性能,从而达到"强节点"的要求。Nonlinear simulation analysis indicates that,in the initial stage of low cyclic reversed loading on exterior stiffener ring connections,plastic zone runs through the annular plate.By means of a comparative study on the joint regional hysteresis curves of column wall and beam end,it is found that the joint hysteresis curves are obtained mainly from the column wall deformation rather than the beam end plastic deformation.To transform the adverse characteristics,oriented reduction is implemented at the beam flange.It is found from nonlinear simulation that the mechanical behavior of the joints is obviously improved in the following aspects：①the stress distribution on annular plate is smoothed obviously,the degree of stress concentration at the corner is significantly decreased;②by changing the size of ring plate or the degree of flange reduction,plastic hinge could be ensured to appear first at the beam end rather than at the ring plate surface;③the joint stiffness does not decrease during the stage of elastic loading;④under cyclic loading,the joint region has little deformation and the plastic expansion on the ring plate surface is not obvious.Above all,reducing beam flange could significantly improve the mechanical properties of exterior stiffener ring joints,thus the requirement of ＂strong joint＂ could be fulfilled.

关 键 词：钢管混凝土 外加强环节点 翼缘削弱 强节点弱构件 

分 类 号：TU352[建筑科学—结构工程]