Bridge structures are key components of infrastructure networks all over the world. Harsh environmental conditions can lead to severe deterioration of structural components, affecting the functionality of the bridge over time. Corrosion represents the main deterioration mechanism in bridge structures, negatively affecting several aspects such as cover concrete strength, reinforcement section, steel strength and ductility, confinement level and bond-slip. It is therefore clear that predictive modeling of the structural performance over time requires to carefully consider these factors in the development of numerical models in order to reproduce realistically the response of deteriorating structures. Given that the numerical model development represents one of the key modules of the Performance Based Earthquake Engineering (PBEE) framework, the assumptions related to the level of detail of corrosion damage modeling affect the results of seismic assessment.
The present contribution investigates the implications of progressively more refined corrosion damage modeling strategies on the long term seismic performance assessment of reinforced concrete (RC) bridges. The extensive numerical investigation is carried out following state of the art PBEE principles and considering a prototype bridge exposed to chloride attack. Chloride diffusion and corrosion propagation are characterized probabilistically through Monte Carlo simulation, accounting for the inherent uncertainty of the process. The results of the seismic assessment are systematically scrutinized through fragility curves and Mean Annual Frequency of Exceedance (MAFE) related to four damage states. The comparison reveals that corrosion damage modeling significantly affects mechanical behavior and long term seismic performance assessment of RC bridges, with differences up to 30% between different approaches.