Experimental investigation of local-overall interaction buckling of stainless steel lipped channel columns

The paper describes an experimental programme carried out at the University of Sydney to study the interaction of local and overall buckling in stainless steel lipped channels under axial compression. Three stainless steel alloys were considered: AISI304, AISI430 and 3Cr12. Material tests were carried out to determine the tensile and compressive properties of the flat plate material and of the cold-worked corners. The results reveal nonlinear stress–strain behaviour with low proportionality limit, anisotropy and enhanced strength as a result of cold-working.A total of 29 column tests were completed with the aim of studying local-overall interaction buckling. The test specimens were designed to fail in the inelastic range to incorporate the effect of the gradual loss of material stiffness into the test results. 11 specimens were tested under a concentrically applied load. The remaining specimens had the load applied with a nominal eccentricity of Le/1500Le/1500 towards the web. Since the cross-section is singly symmetric, the interaction phenomenon is further affected by the shift in effective centroid resulting from local buckling.