Cyclic performance of K-braced cold-formed steel shear walls with concrete-filled steel- tubular struts

A wall consisting of an internal K-braced cold-formed steel (CFS) shear wall and concrete-filled steel-tubular end struts (K-braced RCFS shear wall) is proposed. An experimental investigation on four full-scale specimens under cyclic loading is conducted, based on which a numerical simulation method for analysing the shear performance of the wall is proposed. The results show that (1) The shear strength and elastic stiffness of a gypsum board sheathed K-braced CFS shear wall can be enhanced significantly by adding concrete-filled steel-tubular struts at both ends, the shear failure of the wall is not concentrated in the surrounding screw connections and the end struts play a second defence role in addition to that of the internal CFS shear wall and the wall exhibits a better energy dissipation capacity and ductility after reaching its shear capacity. (2) For a gypsum board sheathed K-braced RCFS shear wall with the web depth of the concrete-filled steel-tubular strut being 140 mm, the prescribed value of the response modification factor R = 3 in AISI is conservative. (3) The proposed numerical simulation method can accurately predict the shear performance of a K-braced RCFS shear wall, and the difference between the simulation and test results is within 11%. (c) 2020 Published by Elsevier Ltd.