Performance of K-braced cold-formed steel shear walls subjected to lateral cyclic loading

The use of Light-weight Steel Framed structures, LSF, has grown dramatically in recent years all over the world but with greater rate of growth in non-seismic regions. Adequate bracing and brace performance is of paramount importance to improve the acceptability of these systems in earthquake prone regions. In this study, the performance of different configuration of K-Brace cold-formed steel shearwalls is evaluated by testing twelve full scale walls of 2.4m×2.4m under cyclic loading. Of particular interest are the specimens maximum lateral load capacity and deformation behavior. The study also looks at the failure modes of the system and investigates the main factors contributing to the ductile response of the LSF walls in order to suggest improvements so that the shear steel walls respond plastically with a significant drift and without any risk of brittle failure, such as connection failure or stud buckling. The walls tested are of different configurations possessing different number of K elements at different locations. The study shows that the K-braced cold-formed steel frames do not perform in an acceptable manner under cyclic loads, because even after preventing some undesirable failure modes like rivet-pull out and shear failure mode in the rivets, there is still left the buckling of the K-elements which is not desirable