（1 同济大学建筑工程系，上海 200092；2 博思格蓝璀建筑钢结构（上海）有限公司，上海 201613）

［摘要］由两个槽形截面构成的抱合箱形截面在超薄壁冷弯型钢结构中应用广泛，但关于其承载力的计算只是将单个构件的承载力简单地数学叠加，并没有相应公式来考虑单个槽形截面构件之间的相互加强。对40根高强冷弯薄壁型钢抱合箱形截面受压构件进行试验研究，考察其受力特性及破坏特征，包括轴压构件21个，绕弱轴偏心和绕强轴偏心构件共19个。试验研究结果表明：抱合箱形截面构件由于两个槽形截面试件的相互约束作用，实测承载力比按单根构件计算承载力叠加结果提高10%~20%左右。最后，在试验和理论分析的基础上，针对高强冷弯薄壁型钢抱合箱形截面受压构件极限承载力提出了一种建议计算方法，依照建议计算方法所得结果与试验结果吻合较好，且偏于安全，可供实际设计参考。

［关键词］超薄壁冷弯型钢；抱合箱形截面；轴压构件；偏心受压构件；极限承载力

中图分类号：TU392.1，TU317.1文献标识码：A文章编号：1002-848X(2011)06-0036-06

Load-carrying capacity of 550MPa high-strength cold-formed thin-walled steel built-up box section columns

Li Yuanqi¹, Yao Xingyou¹, Shen Zuyan¹, Wang Shukun², Liu Xiang¹(1 Department of Building Engineering, Tongji University, Shanghai 200092, China; 2 BlueScope Steel （Shanghai） Co.， Ltd., Shanghai 201613, China）

Abstract:Built-up box section columns by two lipped channel sections are widely used in super thin-walled cold-formed steel structures. However, for their load-carrying capacities of built-up box section columns, usually a mathematical sum according to the load-carrying capacities of each channel section involved is utilized without any further consideration on the reinforcement between single channel sections. Load-carrying capacities and failure modes of 40 high-strength cold-formed thin-walled steel built-up box section columns have been studied, including 21 axially-compressed columns and 19 eccentrically-compressed columns subjected to bending moments along the weak axis and the strong axis respectively. The results show that, due to the interaction between two lipped channel columns connected by self-drilling screws, the ultimate load-carrying capacity of a built-up box section column is 10% to 20% higher than the sum of the ultimate load-carrying capacity of two single lipped channels loaded in the same way independently. Based on the tests and theoretical analysis, a proposed method to estimate the ultimate load-carrying capacity of built-up box section columns reasonably was presented. It can give a close and conservative estimation results, and be referred in practical design.

Keywords:super thin-walled cold-formed steel; built-up box section; axially-compressed columns; eccentrically-compressed columns; ultimate load-carrying capacity

*国家科技支撑计划项目（2006BAJ04A02\|04）。

作者简介：李元齐，博士，教授，Email：liyq@tongji.edu.cn。

参考文献

［1］  GB50018—2002 冷弯薄壁型钢结构技术规范［S］．北京：中国计划出版社，2002.

［2］  RHODES J, HARVEY J M. Interaction behavior of plain channel columns under concentric or eccentric loading［C］// Proc. 2nd Int. Colloquium on the Stability of Steel Structures, ECCS, Liege, Belgium, 1977:439-444.

［3］  THOMASSON P O. Thin-walled C-shaped panels in axial compression ［J］. Journal of Structural Engineering, 1978, 116(5):1230-1246.

［4］  MULLIGAN G P, PEKZ T. Locally buckled thin-walled columns ［J］. Journal of Structural Engineering, 1984, 110(11):2635-2654.

［5］  LAU S C W, HANCOCK G J. Strength tests and design methods for cold-formed channel columns undergoing distortional buckling［R］.  School of Civil and Mining Engineering, Univ. of Sydney, Australia,1988.

［6］  WENG C C, PEKZ T.Compression tests of cold-formed steel columns ［J］. Journal of Structural Engineering, 1990, 116(5):1230-1246.

［7］  KWON Y B, HANCOCK G J.Tests of cold-formed channels with local and distortional buckling ［J］. Journal of Structural Engineering, 1992, 118(7):1786-1803.［8］  YOUNG B, RASMUSSEN K J R. Design of lipped channel columns ［J］. Journal of Structural Engineering, 1998, 124(2):140-148.

［9］  YOUNG B. Experimental investigation of cold-formed steel lipped angle concentrically loaded compression members ［J］. Journal of Structural Engineering, 2005, 131(9):1390\|1396.

［10］  沈祖炎, 李元齐. 高强冷弯薄壁型钢C形截面轴压构件承载力试验研究，高强冷弯薄壁型钢成套技术研究报告No1［R］. 上海: 同济大学、博思格建筑系统住宅部,2007.

［11］  沈祖炎, 李元齐. 高强冷弯薄壁型钢C形截面偏压构件承载力试验研究，高强冷弯薄壁型钢成套技术研究报告No3［R］.上海: 同济大学、博思格建筑系统住宅部,2007.

［12］  DEWOLF J T, PEKZ T, WINTER G. Local and overall buckling of cold-formed members ［J］. Journal of Structural Engineering, 1974,100(10):2017\|2036.

［13］  BEN YOUNG, M ASCE, JU CHEN. Design of cold-formed steel built-up closed sections with intermediate stiffeners ［J］.Journal of Structural Engineering, 2008, 134(5):727-737.

［14］  GB/T228—2002 金属材料\|室温拉伸试验方法［S］.

［15］  李元齐，王树坤，沈祖炎.高强冷弯薄壁型钢槽形截面轴压构件承载力计算模式研究［J］.建筑结构学报，2010，31（11）：17-25.