Flexural strengthening of RC slabs with nonprestressed and prestressed CFRP strips using EBROG method

This paper proposes a fully nonmetallic system for strengthening RC one-way slabs with prestressed CFRP composites. The flexural behaviors of RC slabs strengthened with nonprestressed and prestressed CFRP strips were compared through four-point bending tests. The externally bonded reinforcement on grooves (EBROG) method was utilized to delay premature debonding of the CFRP composites and was compared with conventional externally bonded reinforcement (EBR). The experimental results indicated a significant enhancement in slabs flexural performance of slabs that were strengthened via the EBROG method and the novel anchorage system. The nonprestressed and prestressed CFRP plates attached using the EBROG method increased the bending capacity by 34% and 77%, respectively, compared with the nonprestressed EBR CFRP plate. Furthermore, the maximum CFRP strain reached 8.9 parts per thousand for the nonprestressed EBROG CFRP strip, whereas that for the non-prestressed EBR CFRP strip was only 5.9 parts per thousand. Thus, the EBROG method delayed CFRP debonding and increased the strain in the reinforcement by 50% compared with the EBR method. In the prestressed CFRP strip, the strain reached 12.4 parts per thousand prior to the debonding, confirming the high efficiency of the proposed strengthening system.