Ultimate shear of RC beams with corroded stirrups and strengthened with FRP

Transverse reinforcement plays a key role in the response behavior of reinforced concrete beams. Therefore, corrosion of steel stirrups may change the failure mode of elements from bending to shear, leading to a brittle and catastrophic crisis. It is important to strengthen reinforced concrete beams with corroded stirrups to enhance the shear resistance. This paper presents a formulation, based on the modified compression field theory, to estimate the ultimate shear of reinforced concrete beams strengthened with FRP, because of stirrup corrosion. The detrimental effect of corrosion on steel stirrup yield strength was taken into account by introducing an empirical decay law. The effective strain of FRP reinforcement was adequately evaluated by considering both debonding and tensile stress rupture. The proposed model was validated against collected experimental results, showing a good ability to evaluate shear strength. Moreover, a numerical analysis was carried out to highlight the role of the key parameters predicting the ultimate shear.