Stub Column Tests of Cold-Formed Steel Built-Up Square Sections with Intermediate Stiffeners

This paper describes the experimental and theoretical investigation on ultimate strength of cold-formed steel built-up square stub columns under axial compression. In total, fifteen stub columns were tested by varying the cross-sectional dimensions of specimens. Local buckling, distortion, and interaction of these buckling modes were observed. The strengths obtained from the experiment are compared to the design strengths calculated using the effective width method, which is a direct strength method in the North American Specification for cold-formed steel structures. It was observed that the effective width method conservatively predicted the strength of specimens. The reliability analysis was carried out to evaluate the appropriateness of the design standards.