Investigation and Comparison of the Performance of RC Frames Retrofitted by Slit Damper and Prop Having Ductile Ring

Due to several reasons as the low resistance of constructed concrete and also change in codes or application of structures, some concrete frames need to be retrofitted. By adding the steel prop and curb to the reinforced concrete, many parameters such as resistance, ductility, stiffness and the resistance reduction coefficient change. This study numerically investigates the impact of adding the prop and curb, slit damper, gusset plate and also prop with a ductile ring on resistance, stiffness, ductility and energy dissipation of RC frames. For this purpose, the effect of the aforementioned methods on the linear and nonlinear moment frame behavior of reinforced concrete under monotonic loads have been numerically investigated using the ABAQUS software. Twelve samples of RC frames with one span and one story with the same characteristics were constructed and retrofitted by different methods. All frames were subjected to the monotonic loading, and pushover-displacement graphs of them were plotted. The novelty of the work was using such props and slit damper in RC frames .The results obtained from the modeling showed that although the frame retrofitted by the steel prop and curb showed a better performance in terms of resistance and stiffness, but the retrofitted frame with a ring, slit damper and gusset plate also showed a better behavior in terms of resistance and stiffness compared to the RC frame and the sample with slit damper and prop with a ductile ring as well as compared to the sample with the prop and curb showed more ductility and energy dissipation Also the optimal pattern of reinforcement is in terms of ductility, resistance and stiffness of the slit dampers.