Deteriorated Cyclic Behaviour of Corroded RC Framed Elements: A Practical Proposal for Their Modelling

Corrosion is a phenomenon that significantly impacts the durability of reinforced concrete (RC) structures, particularly in highly corrosive environments like coastal regions. The existing numerical modelling often relies on complex approaches that are impractical for structural assessment. For this reason, this study proposes a simplified numerical modelling approach to simulate the cyclic behaviour of existing RC framed structures with corrosion levels (η) below 25%. The proposed modelling employs concentrated plasticity hinges for beams and fiber sections for columns, incorporating corrosion-induced degradation through modified backbone curves and material properties based on the corrosion level of the structural element. The modelling approach was validated against experimental results from the literature; the proposed model adequately captures hysteretic energy, lateral load, and deformation capacities, with maximum errors of 11% for maximum lateral load, 12% for ultimate load, and 33% for dissipated energy in RC frames. For isolated columns, the errors were 11, 12, and 22%, respectively. In addition, a maximum difference of 7% was found in the lateral load capacity of the corroded frames associated with the Life Safety limit state. Finally, it was concluded that the proposed methodology is suitable for representing the cyclic behaviour of corroded RC columns and frames and provides engineers with a tool to evaluate the behaviour of corroded structures without resorting to complex models.