主管内填混凝土的矩形钢管X型节点受拉和受弯性能试验研究

Experimental research on rectangular steel tube X-joints with chord concrete-inside subjected to tension and bending

为了解主管内填混凝土对矩形钢管X型节点性能的影响,分别进行4个矩形钢管混凝土X型节点和1个矩形钢管X型节点的受拉和受弯试验,试验主要参数为支主管宽度比β和主管宽厚比γ。试验结果表明,主管内填混凝土能够改善节点受力性能,提高节点刚度和承载力,与矩形钢管节点相同,参数β和γ是影响矩形钢管混凝土受拉和受弯节点承载力的主要因素,β越大、γ越小,矩形钢管混凝土节点受拉和受弯承载力越高,节点刚度越大;由于主管内填混凝土的作用,改变了节点破坏模式几何参数的变化范围,节点破坏模式与矩形钢管节点不同。建议套用相应矩形钢管节点承载力计算公式,依据破坏模式来验算矩形钢管混凝土X型节点的受拉和受弯承载力。

To study the behavior of rectangular steel tubular joints with chord concrete-inside, the tests of 4 specimens of concrete filled rectangular steel tube （CFRST） X-joints and 1 specimens of hollow rectangular steel tube （HRST） were carried out under tension and bending loading conditions, respectively. The main experimental parameters studied were the width ratio of branch tube and chord tube β and the ratio of width and thickness of chord tube γ. Test results showed that filled-in concrete of chord tube can improve the mechanical behavior, enhance the rigidity and bearing capacity of the joints. Similar to the HRST joints, the parameters of β and γ are the main factors which influences the behavior, and the bearing capacity and rigidity of CFRST joints become larger for a larger β and smaller γ . Due to the restriction of filled-in concrete to the web of chord tube, the failure mode of CFRST joints are different compared with the HRST joints. The bearing capacity formula are recommended for the CFRST joints according to the failure mode.