Experimental investigation of the behavior of cold-formed stainless and carbon steel braces under cyclic loading

Until today, many studies have been conducted on the experimental behaviors of pipe and square hollow section braces. In thoes studies, the effect of material properties, cross-section shape and loading history on the performance of braces were independently investigated. In this study, the effect of the combined effects of these variables on the performance of steel braces was examined. For this purpose, cross-sectional specimens with approximately 1/3 scale, 6 pipes and 6 square hollow sections, which were cold formed from carbon or stainless steel sheets, were experimentally investigated under 3 different cyclic load effects representing near and far fault loading histories. The buckling strength, energy dissipation capability and displacement ductility of the specimens were evaluated in terms of material properties, cross-section shape and loading protocol. In addition, the buckling strength was compared using European and American standard. Therefore, the buckling strength limits of carbon steel braces in AISC 360-16 and EN 1993-1-1 gave safe results for all loading protocols. However, the buckling strength limits of stainless steel braces in AISC 370-21 and EN 1993-1-4 are safe for far fault loading, but not sufficient for near fault loadings. It has been observed that the most disadvantageous results for the buckling strength, energy dissipation capacity and displacement ductility of the braces can only be obtained by applying different loading protocols. In addition, it has been determined that the effect of material properties on brace performance varies greatly depending on the geometry of the section.