The Effect of Distance Between Steel Core and Steel Sheath on Behavior of Reinforced Concrete Frame Retrofitted with Eccentric Buckling Restrained Braces

The evaluation of the country past earthquakes show that many reinforced concrete buildings in Iran are not earthquake-resistant. Damage to buildings against earthquakes, changing land use, changing guidelines and the development of building, are among the reasons that necessitate the retrofitting. In this research, retrofitting the reinforced concrete frames with conventional concentric and eccentric and buckling restrained braces was analyzed and by changing the distance between core and steel sheath, the effect of these parameters on the behavior of bracing and consequently the structural behavior has been studied. The results showed that by increasing the distance between the core and steel sheath, the deformability of steel core of buckling restrained braced frame is reduced, and localized strength degradations are caused in the retrofitted structure that it was observed reduce of structural energy dissipation by 5-20 %.