Experimental study on the effect of anchorage systems on RC beams strengthened using FRP

In the strengthening of reinforced concrete structures using fibre-reinforced plastic (FRP), the achievement of a strong bond between the FRP and the concrete is beneficial. However, studies have revealed that the bond is often unreliable under high loads, and a means of augmenting the anchorage of the FRP is required to strengthen its bonding with the concrete. In the present study, the effects of various methods for augmenting the FRP anchorage to strengthened concrete structures in the service and failure modes were investigated. This paper presents the results of the experimental investigation of thirty-two beams. The effects of using steel pins, steel clamps, and FRP wraps on the strength of the beams were examined, as well as those of the steel clamp area and the initial compression induced by the clamps. It was found that the strengthening effect and failure mode varied with the adopted FRP anchorage augmentation method. An analysis of the experimental results revealed that the most effective anchorage augmentation method was the use of steel clamps. The application of an initial compression by the clamps was also determined to be beneficial. The highest strength was achieved using a steel clamp of area 50 cm2 and an initial compression of 1 MPa.