Strengthening and rehabilitation of exterior RC beam-column joints using carbon-FRP jacketing

The scope of this study is to present the results of an experimental investigation of the behavior of shear deficient exterior beam-column joints retrofitted by carbon-fibre-reinforced polymers (CFRP's). The joints have no transverse reinforcement so they called non-seismic (NS) joints. Four NS-grade of beam-column joints were tested under reversed cyclic loading and compared with one Seismic joint (S-grade specimen). The experimental program was divided into 3 separated phases including the damaging phase, the repairing phase and the retesting phase. In the third phase of the test, the repaired specimens were tested again until they were reached to final capacity. Results are compared in terms of strength, ductility, energy dissipation and stiffness degradation. A repair-ability performance level of the joints was also achieved through damage index assessment. It is shown that repairing the joints using CFRP laminates is not applicable in damage levels higher than the repair-ability performance level. In this case, the seismic behavior of damaged beam-column joints cannot be improved using CFRP laminates. Finally, it can be concluded that the joints tested in this study, will be repaired up to 1.5 % story drift ratio. Both Park and Ang's and Ghobarah's damage indices regarded to repair-ability of specimens are also suggested.