Behaviour of reinforced concrete frames rehabilitated with concentric steel bracing

The seismic performance of low-rise nonductile reinforced concrete (RC) bui ldings rehabilitated using concentric steel bracing is investigated. A thre e-story building was analysed using various ground motion records. The effe ctiveness of the steel bracing in rehabilitating the three-story building w as examined. The effect of the distribution of the steel bracing along the height of the RC frames on the seismic performance of the rehabilitated bui lding was studied. The behaviour of the nonductile RC frame members is repr esented using a beam-column element capable of modelling the strength softe ning and the effects of the axial force on the yield moment and the deforma tion capacities at peak strength of these members. The performance of the b uilding is evaluated in terms of global and story drifts and damage indices . A simplified approach is proposed for selecting the proper brace distribu tion.