Experimental study on shear behavior of cold-formed steel shear walls with bracket

Abstract

In order to study the shear behavior of cold-formed thin-walled steel shear walls with bracket, 2 cold-formed steel frames and 8 cold-formed steel shear walls sheathed with gypsum boards or OSB were tested under monotonic loading, cyclic loading with vertical loading or not. The lateral stiffness, shear capacity, ductility coefficient and energy dissipation coefficient of cold-formed steel shear walls with bracket were analyzed. It was found that using brackets could enhance the seismic performance of the shear wall effectively and the shear capacity and ductility of cold-formed thin-walled steel framing could be increased by 42.9% and 16.7%. Under monotonic loading, the shear capacity of cold-formed thin-walled steel double-sided boards shear walls with bracket was about twice that of the single-sided boards shear walls minus the shear capacity of cold-formed thin-walled steel frames. The common failure mode for the gypsum specimen was the separation of self-drilling screws and gypsum boards, as a result of local fragmentation in gypsum boards around the self-drilling screw hole. For the OSB specimen, self-drilling screws bent under the effect of the OSB, which followed by nut embedding in OSB, eventually both of them pull-out from steel frame. The vertical loading improved shear performance of cycle loading specimens, especially for the energy dissipation performance of double-sided gypsum board specimens. Based on verifying the correctness of the finite element method, the influence of the length of brackets (projection length of 100 mm, 150 mm and 200 mm, respectively) was analyzed. It was indicated that the wall with the bracket projection length of 100 mm showed better seismic performance than the other two.