Sensitivity analysis of the length of plastic hinge region in the flanged reinforced concrete shear walls

Past earthquakes have shown that properly designed buildings using shear walls have great performance in dissipating a considerable amount of inelastic energy. It is notable that the reduction in seismic input energy occurs in plastic hinge area through inelastic deformation. Plastic hinge development in a RC shear wall in the areas with plastic behavior depends on the ground motions characteristics as well as shear wall details. One of the most generally used forms of structural walls is flanged RC wall. These types of shear walls have large in-plane and out-of-plane stiffnesses through flanges and can tolerate high shear stresses. Several international seismic design codes and guidelines have suggested special detailing to assure ductile response in this region. In this paper, the parameters that affect the length of plastic hinge region in the flanged RC walls were examined and the sensitivity of these parameters was evaluated with respect to the length of the plastic hinge region. Sensitivity analysis was conducted by independently variable parameters with one standard deviation away from their means. To this end, the Monte Carlo simulation, tornado diagram analysis, and first-order second moment method were employed to determine the uncertainties associated with analysis parameters. The results showed that among the considered design variables, the aspect ratio of the flanged RC wall (length to width ratio), length of flange to length of web (lf/lw), and axial load level were the most important design parameters in the plastic hinge region, while the yield strength of transverse reinforcements had the least effect on determining the length of this region.