Reliability-based capacity assessment of corrosion-affected reinforced concrete structures considering strain incompatibility and climate impacts

Corrosion of steel reinforcement is a primary deterioration mechanism in RC structures, which compromises structural capacity by inducing cross-sectional area loss, bond degradation, and strain incompatibility. However, a time-dependent reliability-based framework integrating environmental exposure, corrosion kinetics, bond deterioration, and sectional resistance remains limited. This study proposes an integrated probabilistic framework combining hygro-thermal with corrosion-kinetics to evaluate the flexural and shear capacities of corrosion-affected RC beams. Time-dependent corrosion propagation is predicted using climate-change models which includes temperature and relative humidity as main variables. Sectional capacity is evaluated using compatibility and incompatibility based flexural formulations and a strain based shear model. The proposed methodology is validated against experimental results reported in the literature. Subsequently, the probabilistic resistance degradation and corresponding failure risk of selected bridge girders are evaluated under a fixed load demand, considering the environmental conditions of four coastal cities across different continents. The uncertainties in material and deterioration parameters are incorporated through Monte Carlo simulation to quantify the time-dependent reduction in structural resistance and the associated failure probability. The city-wise increasing order of failure is observed to be consistent with increasing severity of exposure, favourable for corrosion kinetics. Results show that neglecting strain incompatibility leads to significant overestimation of flexural capacity. For all the selected cities and environmental exposure, ignoring strain incompatibility predicts a premature shear failure. The proposed study presents a mechanics-based, reliability framework for assessment and maintenance of corrosion-affected RC structures.