Cold-Formed Lean Duplex Stainless Steel Tubular Members under Concentrated Interior Bearing Loads

In this study, a total of 58 tests were performed on cold-formed lean duplex stainless steel (LDSS) tubular members under three different loading conditions of concentrated interior bearing forces. The loading conditions included interior-one-flange (IOF), interior-two-flange (ITF), and interior loading (IL). The loading conditions of IOF and ITF are specified in the US and Australian/New Zealand cold-formed stainless steel design specifications, and the loading condition of IL simulated the floor joist members positioned on a solid foundation subjected to concentrated bearing load. The cold-formed LDSS specimens were failed by web crippling. The test strengths were compared with the nominal strengths predicted by the international specifications for stainless steel structures. In addition, the strengths predicted by the North American specification for cold-formed carbon steel structures and those from the design equations proposed in the literature for cold-formed duplex stainless steel members were also compared with the test strengths. It was found that the nominal strengths predicted by the international specifications for stainless steel structures are conservative and reliable for cold-formed LDSS members under concentrated interior bearing loads. The predictions by the North American specification were generally unconservative and not reliable, whereas the predictions from the literature were generally less conservative and reliable compared with those predicted by the stainless steel design specifications.