Tests of Cold-Formed Steel Semi-Oval Hollow Section Members under Eccentric Axial Load

This paper describes the experimental study conducted on cold-formed steel semi-oval hollow sections (SOHS) under combined compression and uniaxial bending. Thirty-seven SOHS beam-columns with two different specimen lengths were compressed at various loading eccentricities in order to investigate the load-moment interaction relationship for each test series. The ultimate load-carrying capacities and full load-displacement responses are presented. It should be noted that the design of cold-formed steel semi-oval slender sections is not included in current design specifications. Nevertheless, the sections included in the test program were shown to be compact sections in both compression and bending. Therefore, by incorporating with the interaction curves specified in these design specifications, the test strengths were compared with the design predictions. The applicability and reliability of the current design rules for cold-formed steel compact SOHS beam-column members were assessed in this study. Generally, the predictions by these design specifications are quite conservative and scattered for eccentric loaded compact SOHS, but only the North American and American Specifications are considered to be reliable. Overall, the American Specification provides reliable, less conservative, and less scattered predictions, though further improvements remain possible.