Synergistic shear behaviour of cold-formed steel shear walls and reinforced edge struts

Abstract

A composite structural system in which concrete-filled steel-tubular struts are bolted to a cold-formed steel (CFS) shear wall (C-CFS shear wall system) was proposed to improve the shear performance and stability of conventional CFS shear walls. Full-scale cyclic loading tests were performed to investigate the shear behaviour of the C-CFS shear wall. Furthermore, the synergistic mechanism of the interior shear wall and reinforced edge struts was explored, and a simplified method for calculating the shear capacity of the C-CFS shear wall was proposed. The results show that during the tests, the reinforced edge struts ensured the sufficient deformation of the screw connections in the interior CFS shear wall and maintained the postloading shear capacity of the composite system. Compared with a conventional CFS shear wall with the same dimensions, the shear capacity and elastic stiffness of the C-CFS shear wall were enhanced by approximately 60% and 100%, respectively; moreover, the C-CFS shear wall exhibited a better energy dissipation capacity and ductility after reaching its shear capacity, and the ductility factor of the C-CFS shear wall reached 4.7. The reinforced edge struts interacted with the interior shear wall, and the ratios of the shear forces in the former and the latter to the total structural shear forces stabilized at 20–30% and 70–80%, respectively, forming a reliable lateral resistant system. The shear capacities of the C-CFS shear walls were accurately predicted by the proposed simplified method, and the relative errors between the calculated results and the test results were within 5%.