A Study on the Retrofitting of the Shear Capacity on Cold Joint Longitudinal RC Beams

Strengthening of Reinforced Concrete (RC) beams using GFRP to increase flexural capacity often fails due to premature debonding and delamination of old concrete joints and grouting. The current research introduces a method of repairing and strengthening RC beams using grouting mortar, dyna-bold anchors, and Glass composite FRP (GFRP) sheets. Dyna-bold anchors are used as shear connectors between the old concrete and the grouting. In this research, 10 RC beams measuring 150 mm × 200 mm × 3300 mm, consisting of 2 control specimens (BK), 4 GFRP strengthening beams, and 4 GFRP strengthening beams with dyna-bolt anchors, were tested. The results show that the use of dyna-bold anchors in the joints between old concrete and grouting can increase the bending and shear capacity of the beam by 44.70%, indicating that the addition of dyna-bold anchors is able to prevent premature cracking along the joints and increase the stiffness and flexural capacity of the RC beams. These findings have significant practical implications for the repairing and strengthening of RC beams in real-world applications.