Externally Bonded Reinforcement (EBR) is a common method to install fiber reinforced polymer (FRP) sheets using surface preparation approach. In recent years, a new method called Externally Bonded Reinforcement on Grooves (EBROG) has been introduced as an alternative to the EBR method to strengthen reinforced concrete (RC) beams. In the present study, eight RC beams with 250 mm width, 300 mm depth, and 2200 mm length with two different longitudinal reinforcement arrangements were cast and subjected to the four-point bending test. The specimens were divided into two groups of four specimens according to their strengthening technique, namely EBR and EBROG methods. In addition to the strengthening method, the effects of reinforcement arrangement and concrete strength were investigated. The results show normal strength concrete (NSC) beams strengthened with EBR and EBROG methods experience FRP debonding and concrete cover separation failure modes, respectively. On the other hand, in high strength concrete (HSC) beams both EBR and EBROG methods lead to FRP debonding failure mode. The results also show that the use of the EBROG method in the HSC specimens results in a substantial increase in the ultimate load-carrying capacity, mid-span deflection, and the area under the load-deflection curve up to the maximum load capacity compared to the EBR method. Finally, the comparison between load-carrying capacity obtained from the experimental tests and different analytical models are presented in the study.

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