Hysteresis Evaluation of Discrete Damper with Adaptive Shear Links for Extensively Damaged Reinforced Concrete Frame

The global seismic capacity of an extensively damaged reinforced concrete (RC) portal frame is enhanced by the addition of a discrete damper with adaptive shear link elements. Cyclic tests are performed to evaluate the hysteresis behavior of the proposed damper device with two different sets of shear link elements. Hysteresis performance of the damper-fit RC frame is also evaluated under a displacement-controlled reversed cyclic test. Moreover, a specially designed interlinked coupler-box assembly is used as a local retrofitting technique for restoring the buckled or ruptured longitudinal reinforcing bars of damaged columns in the RC frame. The competency and efficacy of the proposed retrofit techniques are established by comparing the hysteretic behavior, failure mechanism, energy dissipation, strength, and stiffness degradations with the initial tested conventional bare frame. The lateral strength efficiency of the damper-fit model frame is relatively enhanced by 2.5 times with a higher rate of energy dissipation capacity. The proposed damper device functions as a safeguarding element, which protects the principal structural members against lateralinduced damages, and the independent load-transfer mechanism allows for gravity load transfer of the frame despite its nullified lateral strength.