Effect of transverse steel and shear span on the performance of RC beams strengthened in shear with CFRP

This paper presents results of an experimental investigation involving twelve tests on 3000 mm-long reinforced concrete (RC) T-beams strengthened in shear with externally bonded carbon fiber reinforced polymer (CFRP) composites. The main objective of this study was to evaluate the effect of the following parameters on the shear performance of strengthened RC beams: (i) the CFRP ratio, (ii) the transverse steel reinforcement ratio, and (iii) the type of beams (deep versus slender). The results clearly indicated the existence of an interaction between the internal transverse steel reinforcement and the externally applied CFRP in terms of the gain in the shear capacity as well as of the strains. Results also showed the influence of the type of beam on the load capacity gain due to the CFRP. Finally, comparison of the shear resistance values as recommended by the fib TG9.3 (2001), ACI-440R (2002), and CSA S806-02 (2002) guidelines, with the test results clearly indicated that guidelines fail to capture the influence of the studied parameters.