Behavior of Normal and High Strength Reinforced Concrete Corbels Strengthened with Steel Plates

Corbels are short cantilevered structural elements typically extending from walls or columns, characterized by a shear span-to-depth ratio (a/d) less than one. In this study, the structural performance of reinforced concrete corbels strengthened with externally bonded steel plates was evaluated under monotonic vertical loading. The experimental program included six reinforced concrete corbel specimens, each with dimensions of 250 mm span × 150 mm width × 250 mm depth. The investigation focused on three main parameters: concrete compressive strength, that is, 30 MPa for Normal-Strength Concrete (NSC) and 70 MPa for High-Strength Concrete (HSC), the presence or absence of steel plate reinforcement, and two a/d ratios (0.3 and 0.6). The results indicated that the use of steel plates significantly enhanced the structural behavior of the corbels, increasing the ultimate load capacity, crack resistance, and energy absorption. The specimens strengthened with steel plates also demonstrated improved ductility compared to the un-strengthened specimens. These findings confirm that the external steel plate reinforcement is an effective method for enhancing the mechanical performance of both NSC and HSC corbels under vertical loading.