Shear behavior of reinforced concrete beams with drilled opening strengthened by galvanized steel plate

Strengthening drilled openings in reinforced concrete (RC) beams with galvanized steel plates provides a practical and cost-effective alternative to FRP systems. This study experimentally examined seven RC beams: one without openings and six with drilled openings of 78 mm and 103 mm in diameter in the critical shear zone. The beams were strengthened using continuous side-bonded (CSB) plates or U-shaped strips (USS). The ultimate shear capacity decreased by 49.17% and 59.75% for 78 mm and 103 mm openings, respectively. Results showed that strengthening with galvanized steel plates significantly improved shear capacity. The CSB scheme increased shear capacity by 95% and 140.20% for CSB78 and CSB103, while USS78 and USS103 increased shear capacity by 91.2% and 51.71% compared with B78 and B103. Overall, galvanized plates enhanced beam strength and ductility, altered failure modes, and an analytical method was proposed to predict the shear capacity of strengthened RC beams with openings.