双肢开孔冷弯薄壁型钢拼合箱形截面立柱轴压性能有限元与理论分析

Numerical analysis and theoretical study on cold-formed thin-walled steel double limbs box section columns under axial compression

为了研究双肢开孔冷弯薄壁型钢拼合箱形截面立柱的轴向受力性能,采用有限元方法对拼合箱形截面立柱长细比、腹板宽度、试件厚度、开洞情况及孔洞间距等参数进行了非线性分析,并将有限元结果与《冷弯薄壁型钢结构技术规范》（GB 50018—2002）＂有效宽度法＂计算未开孔试件承载力进行对比。综合考虑腹板孔洞影响,对构件轴压承载力进行折减,提出了适合双肢开孔冷弯薄壁型钢拼合箱形截面开孔试件轴压承载力计算的建议修正公式。分析结果表明：试件轴压承载力会随长细比增大及腹板孔洞的出现而减小;腹板位置处开孔洞会对试件极限承载力和破坏位置产生较大影响;开洞间距的大小不能明显改变多孔试件的极限承载力,也不会改变多孔试件的屈曲失效模式。

In order to study the structural behaviour of cold-formed thin-walled steel double limbs box section columns under axial compression,the verified finite element model was used for an extensive parametric study. Factors including slenderness ratio,web width,specimens thickness,holes and holes spacing were analyzed. The numerical study results were compared with the results calculated by ＂effective width method ＂ in Technical specification for cold-bending thin-walled steel structure（ GB 50018—2002）. Considering the influence of web plate hole component,the axial compression bearing capacity was reduced,and modified formula of axial bearing capacity for cold-formed thin-walled steel double limbs box section columns specimens was proposed. The analytical results show that the axial bearing capacity of specimen decreases with the increment of slenderness ratio and the appearance of holes in the web. Moreover,the holes in the web have a significant influence on the ultimate bearing capacity and failure location of specimens. The holes spacing has little influence on the ultimate bearing capacity and failure mode of specimens with holes.