Experimental Investigation On Load-Carrying Capacity Design Method For Eccentrically-Compressed High-Strength Cold-Formed Thin-Walled Steel Columns

Recently, The use of High-strength steel cold-formed thin-walled sections with yield stress values up to 550MPa is increasing rapidly in low-rise and multi-story residential buildings and portal steel frame structures in developed countries. Unlike conventional 235MPa and 345MPa yield structural steels that are highly ductile and strain harden, Steels with high yield stress usually have characters of high strength, low ductility and little or no strain hardening in the stress-strain curve. However, the application and popularization of the new materials in China is still limited, and there are no related provisions in current design codes 《Technical Code of Cold-formed Thin-Walled steel structures》 (GB50018-2002) for reference in engineering practice. In order to populize this High-strength steel in China, further research work is very necessary to investigate the design methods and the design reliability of the high-strength cold-formed thin-walled steel structures.BlueScope Buildings, Residential, Dept. of Building engineering and Tongji University have co-worked and carried out series of experimental research about High-strength steel cold-formed thin-walled sections(G550). This paper is the second stage of this research project, mainly about eccentrically-compressed High-strength cold-formed thin-walled steel columns and axial-compressed compression tests of C-sections columns failing in the distortional mode.This paper can be divided into two parts. First, experimental investigation of load-carrying capacity for eccentrically-compressed 550MPa High-strength cold-formed thin-walled steel columns. A total of 67 members were tested(including different sections, different thickness, different slenderness ratios and different loading direction). Based on comparing the test results and calculations by the design specifications of Chinese code GB50018-2002 and othercountries', limit load-carrying capacity estimation methods for eccentrically compressed 550MPa high-strength cold-formed thin-walled steel columns are proposed and the reliability are analysed. Second, experimental investigation of the distortional buckling of...