FRCM shear strengthening for concrete beams

This paper presents the results of an experimental study carried out to examine the efficacy of Fabric-Reinforced Cementitious Matrix (FRCM) in strengthening RC beams susceptible to shear failure. In this paper, seven shear-critical RC beams, of 2,500 mm in length, 150 mm in width, and 330 mm in depth, were tested under three-point loading until failure. Two main test variables were considered, which are: A) Strengthening material: carbon, polyparaphenylene benzobisoxazole (PBO), or glass FRCM, and b) Strengthening application pattern: A single full-length FRCM plate or a set of intermittent and spaced FRCM strips were applied along the critical shear zone. The test results confirmed the efficacy of FRCM strengthening in improving the load capacity of shear-critical RC beams. The FRCM-strengthening contributed to increases in the load capacity ranged between 31% and 100% compared to the reference specimen. The full-length strengthened specimens generally showed a better strength enhancement compared to the intermittent counterparts when using the same FRCM material. Such intuitive observation assures the importance of the amount of strengthening material applied in the critical shear zone. Besides, specimens utilizing carbon fibers in its FRCM strengthening material showed the highest strength enhancement among the three systems.