圆钢管混凝土T型节点在轴向作用力下静力性能研究

Static Strength of Concrete-Filled Circular Tubular T-Joints under Axial Loading

T型圆管节点在支管轴向力作用下,破坏位置一般出现在主管表面的焊趾处.主要是因为主管的径向刚度远小于支管的轴向刚度,并且节点部位存在较大的应力集中.为提高T型管节点的静力强度,可通过在主管中填充混凝土以提高其径向刚度来实现.为了研究主管填充混凝土对T型管节点静力强度的影响,用有限元分析软件(ABAQUS)首先对6个模型分别在支管轴向压力和拉力作用下进行分析,结果发现主管中填充混凝土对节点静力强度的提高是非常有效的.同时得出主管填充混凝土与未填充混凝土节点不同的破坏模态.然后,对圆钢管混凝土T型节点进行参数分析,参数主要包括主管厚度T、支主管管径比β、主管的径厚比2γ、钢材屈服强度fy、混凝土抗压强度fc.通过参数分析,得出T型圆钢管混凝土节点静力强度随不同参数的变化规律.

For typical tubular T-joint under axial loading,the failure generally occurs near the weld toe on the chord surface due to the fact that the stiffness of the chord in radial direction is much smaller than that of the brace in axial direction as well as the existence of high stress concentration along the weld toe.The static strength of tubular T-joints can be improved by filling concrete into the chord.Finite element analysis is conducted to analyze 6 T-joint models under axial compression and tension by using sofware ABAQUS to prove that filling concrete in the chord is effective to improve the static strength.Different failure modes under axial compression and tension between tubular T-joint with circular hollow section and Concrete-Filled Circular Tubular（CFCT）T-joint are clarified.Thereafter,parametric investigation for CFCT T-joint,which involves the parameters of chord thickness T,the brace/chord diameter ratio β,the chord diameter/thickness ratio 2γ,the yield strength of the steel tube fy,and the compressive strength of concrete fc,is carried out.From the parametric study,the effect of parameters on the static strength of CFCT T-joints is concluded.