圆钢管混凝土K型焊接管板节点试验研究和有限元分析

Experimental study and finite element analysis of concrete-filled circular steel tubular K-type welded tube-gusset joints

以组成K型焊接管板节点的塔柱径厚比γ、腹杆与塔柱管径比β和壁厚比τ,节点板厚度与腹杆壁厚比t_g/t_i为参数,对4个圆钢管混凝土K型焊接管板节点和1个空心圆钢管K型焊接管板节点进行试验,研究该类型节点的破坏模式、承载能力以及节点区的受力特点,并采用有限元方法分析各参数对圆钢管混凝土K型焊接管板节点受力性能的影响规律。研究结果表明:随着所取参数的变化,圆钢管混凝土K型焊接管板节点存在腹杆失效和节点板失效2种破坏模式;而空心圆钢管K型焊接管板节点的破坏模式为塔柱管壁过度塑性变形失效。说明钢管中混凝土的填充改变了节点的受力特点和破坏模式,有利于材料承载能力的充分发挥。节点板厚度与腹杆壁厚比t_g/t_i是影响圆钢管混凝土K型焊接管板节点破坏模式和极限承载力的关键因素。在实际工程中,为避免出现节点失效,t_g/t_i的取值宜大于2。

Four concrete-filled circular steel tubular（CFCST） K-type welded tube-gusset joints and a hollow circular steel tubular（HCST） K-type welded tube-gusset joint were tested, and the test parameters included the diameter thickness ratio γ of tower column, diameter ratio β and thickness ratio τ between web and tower column, thickness ratio tg/ti between gusset plate and web. The failure modes and bearing capacities of these joints were investigated and compared, and the stress characteristics of joint area were analyzed. The influences of these parameters on the mechanical behavior of the CFCST joint were studied by the finite element method. The results indicate that the failure of the CFCST K-type welded tube-gusset joints occurs at the compression web and gusset plate, while the HCST K-type welded tube-gusset joint finally fails because of excessive plastic deformation of the tower column. The filling concrete in tower column changes the failure mode and stress characteristics of joint and gives full play to the bearing capacity. The tg/ti is the key factor affecting the failure mode and bearing capacity of the CFCST K-type welded tube-gusset joint. In practical engineering, in order to avoid the failure of this kind of joint connection, the suitable tg/ti should be more than 2.