Different FRCM systems for shear-strengthening of reinforced concrete beams

Abstract

This paper presents the results of an extensive experimental study on the efficacy of different fabric-reinforced cementitous matrix (FRCM) systems for the strengthening of reinforced concrete (RC) beams, which are critical in shear. Three types of FRCM systems were assessed; namely, Carbon-FRCM, polyparaphenylene benzobisoxazole (PBO)-FRCM, and Glass-FRCM. Tensile characterization tests were carried out on fifteen (15) FRCM coupons with the purpose of identifying the tensile properties of the FRCM systems. In the core part of this study, sixteen (16) shear-critical RC beam specimens were tested under three-point loading for assessing the effect of FRCM stiffness/type, FRCM configuration, and FRCM anchorage on the load and deformational capacities of the strengthened beams. As for the study results, the average enhancement of the load carrying capacity achieved by FRCM strengthening with respect to the reference specimen is 51%. Continuous strengthening significantly improved all aspects of structural performance of the strengthened beams compared to those of the intermittent counterpart. The effect of FRCM configuration appeared to be significantly related to the amount and the orientation of the effectual fabric within the FRCM system. Moreover, the effect of the FRCM anchorage used in this study was observed to be insignificant on the load carrying capacity of the strengthened beams. Theoretically-predicted values for load carrying capacity were obtained, and showed a reasonable agreement with the experimental results.