Repair and strengthening of reinforced concrete beam-column joints with fiber-reinforced polymer composites

Three exterior reinforced concrete beam-column joint specimens were tested under reverse cyclic loading. The joint region of these specimens suffered significant damage, whereas limited damage was observed in the beams. The damaged specimens were repaired and strengthened to prevent shear damage and strength deterioration inside the joint region and to achieve more ductile response. First, the damaged loose concrete was removed and replaced by high-strength nonshrink mortar. Then, fiber-reinforced polymer (FRP) strips were diagonally wrapped over the joint region, and longitudinal FRP strips were applied and anchored on the beams. The original strength was restored in all strengthened specimens under the application of the same loading history. Deformation capacities of the strengthened specimens were much larger than those of the original specimens.