Cyclic performance of cold-formed steel shear walls sheathed with double-layer wallboards on both sides

Abstract

To satisfy the requirements of fire resistance and loading capacity of the walls in multi-story cold-formed steel (CFS) structures, shear walls sheathed with double-layer wallboards on both sides were proposed. Sheathing materials in these walls included gypsum wallboard (GWB), bolivian magnesium board (BMG) and calcium silicate board (CSB). Cyclic loading tests on six full-scale walls of this configuration were conducted, from which the shear performance of the walls could be obtained. Factors such as the sheathing material, aspect ratio, stud section and stud spacing were considered. Another experimental study on the shear behavior of the screw connections was also performed to explore the potential relationship between the walls and the screw connections in shear performance. The results showed that the peak strength of the walls sheathed with bolivian magnesium boards as the face layer wallboards significantly exceeded the nominal value of the current standard. However, for the walls sheathed with calcium silicate boards as the face layer wallboards, the tested walls exhibited brittleness damage with poor ductility after the peak strength. The equivalent-bracing model was used to calculate the lateral stiffness of the walls, based on which a series of screw connection deformation limits and shear-wall drift angle limits was suggested.