Effectiveness of frcm system in strengthening rc beams in shear using hybrid nse/eb technique

Abstract

This paper presents an experimental study on the efficacy of a recently introduced hybrid "near surface embedded/ externally bonded" NSE/EB fabric reinforced cementitious matrix (FRCM). Seven medium scale RC beams, deficient in shear, were constructed and tested under three-point loading. Six beams were strengthened using hybrid NSE/EB-FRCM technique and one beam was left un-strengthened as a reference. Two main test variables were considered; viz., strengthening configuration: full versus intermittent strengthening configuration and FRCM type: glass FRCM versus polyparaphenylene benzobisoxazole (PBO). The test results revealed that the hybrid NSE/EB-FRCM strengthening technique is effective in enhancing the shear capacity of the strengthened beams. The strengthened specimens showed an average of 67% higher shear capacity relative to the reference specimen. With regard to the FRCM type, G-FRCM strengthened specimens showed an average of 73% enhancement in the shear capacity, which was 12% higher than the value for PBOFRCM counterpart. Moreover, the strengthened beams showed higher deflection at the ultimate load than that of the reference specimen. Furthermore, the hybrid NSE/EBFRCM technique has shown to be a promising alternative to the conventionally used externally bonded FRCM system with the potential to reduce the debonding of FRCM from the concrete substrate.