Shear strengthening of reinforced concrete beams using bamboo fibre-reinforced composite plates

This paper experimentally investigates the structural behaviour of reinforced concrete (RC) beams strengthened in shear using bamboo fibre-reinforced composite (BFRC) plates. The study evaluates the effects of fibre content, resin matrix (epoxy or vinyl ester), and mechanical affixation methods. Bamboo ( Gigantochloa scortechinii ) was delignified with 10% NaOH and fibre-extracted using a roller mill. BFRC plates were fabricated via hand lay-up with fibre volume fractions ranging from 0 to 50%. Results show that BFRC mechanical properties improved with higher fibre content across both matrices. The 45% bamboo fibre-epoxy composite (BFREC) exhibited the highest tensile and flexural strengths (268.7 MPa and 272.0 MPa, respectively). Consequently, a 90° orientation with 45% BFREC proved to be the most effective configuration, shifting the RC beam failure mode from brittle to ductile. Additionally, bolted BFRC plates increased the ultimate load capacity by ~2% compared to adhesive bonding alone. Overall, BFREC plates demonstrate strong potential for structural shear strengthening.