双槽钢缀板柱绕虚轴的滞回性能试验研究

为研究双槽钢缀板柱绕虚轴的抗震性能,对6个双槽钢缀板柱足尺试件进行水平往复荷载试验研究,分析了单肢长细比、缀板线刚度、轴压比、加劲肋设置等因素对试件的承载力、破坏模式、耗能能力、变形能力及延性的影响。试验结果表明:按GB 50017—2017《钢结构设计标准》设计的双槽钢缀板柱在绕虚轴往复荷载作用下不能达到设计塑性受弯承载力,减小单肢长细比,可显著提高构件塑性抗弯承载力及初始刚度,当单肢长细比为20时,构件绕虚轴受弯承载力可达到规范相关要求;在满足规范要求的情况下,缀板及其连接焊缝未发生破坏,但提高缀板线刚度对构件绕虚轴的抗震性能影响较小;轴压比对构件抗震性能影响显著,随着轴压比增大,构件抗震性能降低;在构件塑性铰区设置加劲肋,可有效防止该区域板件的局部屈曲,提高构件的承载力、延性及耗能能力,缓解承载力及刚度退化,但塑性铰区转移至第二与第三块缀板间,试件破坏模式为单肢失稳。

Experimental study on hysteretic behavior of built-up battened double-channel steel columns about hollow axis

To study the seismic behavior of built-up battened double-channel steel columns about hollow axis, the quasi-static tests of six full-scale specimens subjected to reversed cyclic loading were conducted. The influences of the slenderness ratio of individual member, axial-load ratio, stiffness of batten plate and stiffeners on the load carrying capacity, failure modes, energy dissipation capacity, deformation capacity and ductility were analyzed.The test results indicate that the built-up battened double-channel steel column designed according to GB 50017—2017 ‘Standard for design of steel structures’ fails to reach expected plastic moment-carrying capacity. The reduction in slenderness ratio of individual member is found to be beneficial to increase moment-carrying capacity and lateral stiffness of the columns. The columns achieve the expected moment-carrying capacity when the slenderness of the individual member is 20. No failure is observed in the batten plates or their fillet weld which conforms with the current design code. The increase in stiffness of batten plates shows ignorable influence on the seismic behavior of the column. The axial-load ratio shows significant influence on the seismic behavior of the columns. The seismic behavior of the column is deteriorated with the increasing axial-load ratio. Stiffeners locating at the plastic hinge region can fully eliminate local buckling of plates, leading to improvement in strength, ductility and energy dissipation capacity of columns with mitigating the degradation of the strength and the stiffness of the column. But the present of the stiffeners moves the plastic hinge to the location between the 2nd and 3rd batten plates. The failure mode is still buckling of the individual member of the column.