带垫板的双肢背靠背C型钢组合柱承载力分析

针对带垫板的双肢背靠背C型钢组合柱,通过试验和有限元模拟分析,研究该类型组合柱在偏心荷载作用下的受力特性,就偏心距、长细比、垫板厚度和间距等参数对组合柱承载力、刚度与轴向荷载的关系和M-φ曲线的影响进行讨论。结果表明:C型钢腹板和受压翼缘在整体失稳之前出现了严重的局部屈曲,组合柱的破坏模式均为弯矩作用平面内的弯曲失稳。长细比、偏心距和垫板间距是影响组合柱受力性能的主要因素,垫板厚度的影响有限。最后与规范GB 50018—2002《冷弯薄壁型钢结构技术规范》规定的柱承载力的计算方法进行对比,对该类组合柱的承载力计算给出了相关建议和承载力计算的修正系数。

ANALYSIS OF BEARING CAPACITY OF DOUBLE COLD-FORMED THIN-WALLED C STEEL BACK-TO-BACK COMPOSITE COLUMN WITH PLATE COUPLED

According to the composite column of double cold-formed thin-walled C steel back to back connected with gusset plate,the test and finite element analysis were carried out to study the stability bearing capacity and failure modes of the specimen under eccentric loading. The elements such as slenderness ratio,gusset plate thickness and gusset plate spacing were discussed,which produced the impacts to composite column's bearing capacity,the relationship between stiffness and axial loading,and the curves of M-φ of eccentricity. The results revealed that before the overall instability the local-buckling was occurred,the failure modes were belonging to the in-plane-flexural buckling. The major factors are slenderness ratio,eccentricity and gusset plate spacing which effected the mechanical behavior,while the gusset plate thickness has no obvious impact. In the end,the calculation method of the bearing capacity of the cold-formed thin-walled column was compared with that in "Technical Code of Cold-Formed Thin-Walled Section Steel Structures"( GB 50018—2002),some suggestions based on the type of composite section column calculation were put forward,and the bearing capacity correction coefficient of the steel composite columns was given.