Analytical assessment of the bearing capacity of RC beams with corroded steel bars beyond concrete cover cracking

Corrosion of steel reinforcement is one of the major causes that limit durability and serviceability performance of reinforced concrete (RC) structures. This paper reviews thoroughly available experiments and analytical approaches in the relevant international literature and introduces a calculation model for assessing steel bar mass loss and contributes to further utilization of common in-situ inspections from a structural point of view. The model is based on the width of longitudinal crack of concrete cover, as a function of cover depth, bar diameter and mechanical properties of concrete. The model includes the well-known relationships for the steel mass loss during the first phase of rust formulation, filling the porous zone as well as during the phase that the radial pressure exceeds the concrete strength and causes cover cracking. The assumption followed herein for the flexibility of cracked concrete allows for the estimation of steel bar corrosion rate even beyond concrete cover cracking, by visual mapping of the width of longitudinal cracks. Then, the corresponding flexural capacity of the beams at yield and at maximum may be assessed. The predictions of the model are validated against 51 non-strengthened corroded beams and 24 strengthened corroded beams with Fiber Reinforced Polymer (FRP) materials published in the international literature.