An enhanced analytical model for predicting shear strength in reinforced concrete beams with corroded reinforcement

Abstract This paper presents an analytical model to predict the shear strength of RC beams affected by corrosion within the Level IIb framework of fib Model Code 2020. Corrosion is accounted for by (i) reducing the area of longitudinal reinforcement, (ii) degrading the yield strength of stirrups according to Imperatore's law, and (iii) reducing the effective concrete width due to cover cracking and spalling. The model is solved iteratively by explicitly considering the average longitudinal strain state and the contribution of both concrete and transverse reinforcement to shear transfer. A curated database of 108 tests (76% corroded) on slender beams is compiled to validate the model and benchmark it against established formulations (MC2020 approach IIa, Rossi and Spinella, Cladera, Juarez, Xu, and Lu). Overall, the proposed method attains a mean analytical‐to‐experimental ratio of 1.00 with a coefficient of variation of 25%. The dispersion increases with the corrosion level and in small‐scale specimens, while full‐scale tests, though fewer, are captured satisfactorily. Compared to the reference formulations, the present approach yields a balanced trade‐off between accuracy and conservativeness and is therefore well suited for structural assessment. Scope and limitations are discussed, and guidance is provided for practical application and future extensions to members under axial load and prestress.