Nowadays, Buckling-Restrained Braced Frames (BRBF) are mainly used as lateral load-resisting systems in seismic areas. Two characteristics of higher energy dissipation capacity and lack of existence of buckling behavior have been caused that buckling-restrained brace to be a better alternative to conventional bracing. In this study, the response modification factor (R-factor) and other parameters of buckling of Reinforced Concrete Frame (RCF) with BRB bracing (RCF-BRB) have been investigated. The (R-factor) is a function of different parameters, which to determine these coefficients, the nonlinear static pushover analysis in accordance with ATC-19 and two methods of equal energy and Priestley & Paulay were used to evaluate the plastic behavior of RCF with and without BRB bracing. The result showed that the lateral stiffness of RCF-BRB decreases with increasing the number of stories so that in the number of high stories, the lateral stiffness of RCF-BRB becomes very close to the lateral stiffness of the RCF.
