Steel Struts under Severe Cyclic Loadings

An experimental study is presented of the inelastic behavior of axially loaded steel members subjected to repeated buckling and stretching. Tests on 24 commercially available steel struts commonly used as bracing members are reported. A large variety of shapes were tested including wide flanges, structural tees, double-angles, a double-channel, and thick and thin-walled square and round tubes. The boundary conditions were of two types, pinned-pinned and fixed-pinned, while the effective slenderness ratios were either 40, 80, or 120. The effects were investigated of loading patterns, end conditions, cross-sectional shapes, and slenderness ratios on the hysteresis response of members. An explanation is given regarding the fundamental mechanisms responsible for the observed degradation in the buckling load capacity during inelastic cycling.