方中空夹层钢管混凝土压弯扭构件试验研究

Experimental study on concrete-filled double-skin square steel tubes under compression-bending-torsion loading conditions

以长细比、空心率和轴压比为主要变化参数,进行了5个方中空夹层钢管混凝土和2个方实心钢管混凝土压弯扭构件的试验研究。采用有限元软件ABAQUS对压弯扭试件的扭矩-转角全过程关系进行计算,计算得到的扭矩-转角关系曲线在达到承载力之前与试验结果符合较好。通过典型算例进行计算,从钢管与混凝土各自承担的荷载、轴压比和空心率对扭矩-转角关系曲线的影响三个方面对方中空夹层钢管混凝土压弯扭的工作机理进行了分析。研究结果表明:随着轴压比(n≥0.2)的增大,试件抗扭强度承载力越小;偏心率较小时,空心率越大抗扭承载力越大,延性越好。

In this paper,totally seven specimens including two concrete filled steel square tubes and five concrete filled double-skin square steel tubes with various slenderness ratios,hollow ratios and axial force ratios were tested under compression-bending-torsion loading conditions. The torsion-rotation curves of all specimens were numerically calculated by finite element software ABAQUS. The numerical results are found to be in good agreement with test data before the load carrying capacity is obtained. The working mechanism is analyzed by parametric studies with respect to the separate carrying load of steel and concrete and the influence of axial force ratio and hollow ratio on the response of the torsionrotation curves. The parametric study results indicate that the torsion capacity decreases with the axial force ratio. The torsion capacity and ductility increases with the hollow ratio when the eccentricity is relatively small.