Experimental Study of Reinforced Concrete Frame Rehabilitated by Concentric and Eccentric Bracing

Adding steel braces to reinforced concrete frames is a common way for seismic rehabilitation of these structures. Due to ease of installation and the possibility of creating openings in the braced bays, this method of rehabilitation has been more preferred than using shear walls. In this paper, three experimental specimens including a reinforced concrete frame, a reinforced concrete frame with concentric bracing and a reinforced concrete frame with eccentric bracing are constructed and their cyclic behavior investigated and compared with each other. Results show that the ultimate loads of the both concrete frames with concentric and eccentric braces are about 2.11 and 1.9 times more than that of reinforced concrete frame, respectively. Ductility of rehabilitated frame by eccentric bracing is more than that of reinforced concrete frame and rehabilitated frame by concentric bracing too. Moreover, the absorbed energy of the rehabilitated frames with eccentric and concentric bracing is about 1.98 and 1.63 times more than that of concrete frame.