Efficient bidirectional U-wrap system to anchor CFRP sheets bonded to reinforced concrete T-girders

Externally bonded fiber reinforced polymers (FRP) has been established to be an effective method for strengthening reinforced concrete beams, especially when it is properly anchored so that the premature debonding failure mode is avoided. In this study, five reinforced concrete T-girders were constructed, with the first girder being a control specimen. The remaining four girders were then strengthened with one CFRP sheet. One of them was tested without anchorage while the other three beams had the CFRP sheet anchored with various configurations and amounts of +/- 45 degrees bidirectional glass FRP U-wraps. The goal of the experimental program was to evaluate the performance of the anchorage systems in order to compare the flexural strength to that of the unanchored and control specimens. Also, the comparison of the different U-wrap configurations was determined to address the most effective layout. The experimental program allowed concluding that the three anchored girders showed increase in flexural strength when they were compared to the control and unanchored girders. Furthermore, the anchored girders reached similar capacities so the configuration with the lowest amount of +/- 45 degrees bidirectional glass FRP U-wraps was the most efficient.