Numerical and experimental study on the response of composite shear walls with cold-formed steel sheets under cyclic loading

Due to structural and architectural requirements, reinforced concrete shear walls, which are used in high-rise structures to resist seismic forces, are preferred with smaller cross-sections to create more usable floor plans. For that reason, shear walls are created with narrow cross-sections including excessive steel rebars. However, intensive reinforcement may cause difficulties in concrete pouring and segregation which is especially seen in the boundary zone elements of the reinforced concrete shear walls. To overcome certain problems, composite shear walls have been investigated by many researchers as an alternative to the conventional reinforced concrete shear walls. Within the scope of this study, the behaviors of composite shear walls, which are designed using cold-formed steel sheet elements and proposed as an alternative to the composite shear walls existing in the literature, were experimentally and numerically investigated under cyclic loading. A total of three shear wall test specimens, including one conventional reinforced concrete and two composites, were manufactured on a 1/3 scale and the specimens were tested under cyclic loading. After the experiments, two composite shear walls were retrofitted and tested again under the same conditions. The dimensions of the cold-formed steel sheets used in the shear wall end zones are 2×L19×57×7, 4×L23×69×5, and 2×L17×49×7 in mm. During the tests, the crack propagation in the specimens was investigated at each loading stage, and the behaviors of the walls were defined by the lateral force-top displacement relationship. The lateral load capacity, ductility, dissipated energy, and rigidity parameters were investigated comparatively and a new approach to repair and retrofit the damaged specimens was presented. In addition, numerical analyses were conducted using finite element software. According to the results, numerical models of the conventional and composite shear walls are validated with experimental results, and it has been shown that the numerical models successfully simulate the shear wall behavior. A parametric study was also conducted using the validated numerical models and the effects of material behavior of the steel sheet elements on the behavior of composite shear walls were investigated.