中柱失效下钢管混凝土柱梁节点力学性能分析

Mechanical properties analysis of concrete-filled steel tube column beam joints under middle column failure

为研究钢管混凝土柱-H型钢梁下栓上焊节点在中柱失效模式下钢梁的传力性能,设计了腹板连接板处开圆孔和长圆孔的2根试件,进行了静力加载试验研究,分析了钢梁的传力特性和不同机制对竖向荷载抗力的分担。结果表明:该新型节点远端钢梁试验时始终处于弹性状态,可采用相关公式计算钢梁内力;在贯通隔板范围内钢梁受其抗弯性能影响较大。试件屈服前主要由钢梁抗弯机制提供竖向抗力,屈服后转由悬索机制提供,整个试验过程钢梁抗弯机制并未消失,破坏前一直处于拉弯状态;腹板连接板开设长圆螺栓孔可以提高节点转动能力,更有利于钢梁轴力提供竖向抗力。同时,提出并验证了该新型节点形式在框架结构中刚性连接的假定,给出了极限面荷载参考值。

In order to study the force transfer performance of concrete filled steel tubular column-h-type steel beam with lower bolted and upper welded connecting joint under middle column failure,two specimens with round and long round holes at the web connection plate were designed.The static loading test was carried out to analyze the force transmission characteristics of steel beams and the sharing of vertical load resistance by different mechanisms.Results show that the far-end steel beam of the joint is always in the elastic state during the test and its internal force can be calculated by the relevant formula,and the steel beam within the scope of the perforation plate is greatly affected by its bending resistance.In addition,the vertical resistance is mainly provided by the steel beam bending mechanism firstly and then it is replaced by the catenary mechanism after beam yielding.The bending mechanism of the steel beam exists all the time and it is always in the bending state before the failure.The long round bolt holes can improve the rotation ability of the joint,so is more favorable for steel beam axial force providing vertical force.Meanwhile,the assumption of the rigid connection of the new joint form in the frame structure is proposed and verified,and the reference value of the limit surface load is given.