Cyclic response and damage status of coupled and hybrid-coupled shear walls

Individual shear walls can be linked using coupling beams to unify their individual actions in one system called coupled or hybrid-coupled walls if coupling beams are reinforced concrete (RC) or steel, respectively. The coupled and hybrid coupled walls response is strongly influenced by the coupling and axial stress ratios. In this research, therefore, using well-calibrated numerical models, a parametric study was undertaken considering these ratios as study variables to investigate the seismic performance and response features of coupled and hybrid-coupled walls. Sixty different scenarios were defined by varying the coupling ratio and axial stress ratios within the range of 0.2-0.5 and 0.027-0.25 to conduct the study. The research results demonstrated that for both coupled and hybrid-coupled walls increasing the coupling ratio changes the damage pattern and leads to more and severe damage along the outermost edges of shear walls; moreover, it increases the lateral capacity, secant stiffness and dissipated energy but decreases the ultimate drift. RC coupling beams can better interact with shear walls and experience severe damage, but steel coupling beams experience minor shear deformation and can longer provide coupling action. Increasing the axial stress ratio reduces the ductility ratio, response modification and displacement amplification factors for coupled and hybrid-coupled walls. Although increasing the coupling ratio in coupled walls decreases the ductility ratio, response modification and displacement amplification factors, it does not have an appreciable effect on hybrid-coupled walls response features. Moreover, coupled and hybridcoupled walls with higher axial stress ratio show less ductile behavior (i.e., more column-like response).