TIME-DEPENDENT CORROSION AND SEISMIC FRAGILITY: A FRAMEWORK FOR LONG-TERM RISK MITIGATION

Gili Lifshitz Sherzer; Alon Urlainis; Igal M. Shohet

Abstract:

This research introduces a novel procedure for considering corrosion effects within critical infrastructure exposed to seismic risk, focusing on reinforced concrete structures. Most conventionally developed seismic fragility curves cannot assess the progressive material degradation over time, such as corrosion. At the same time, the present study proposes a novel approach that explicitly incorporates corrosion-driven deterioration in seismic vulnerability assessment. The proposed framework couples time-dependent corrosion modelling with FDEM numerical simulations to assess deterioration in structural integrity. These results are used to update seismic fragility curves that accurately capture the increased vulnerability of corroded structures to earthquake-induced damage. The significant contribution of this research is developing an integrated risk assessment model that merges the corrosion-adjusted fragility functions with seismic hazard analysis for long-term seismic risk assessments. The primary novelty within the methodology formulation involves developing a cumulative risk ratio, expressing the overall accumulation of risk during the structure's service life. In this context, this framework has been validated with a case study of a single-story RC moment frame for different corrosion scenarios and spatial distributions. The numerical results agreed well with empirical data by a 3-14% discrepancy for the projected 75-year life cycle period. The results indicate a considerable increase in seismic risk due to corrosion effects: 59% for moderate and 100% for intense corrosion environments. The findings highlight that considering the mechanisms of corrosion during seismic risk assessment allow for more realistic seismic risk assessment and ameliorate critical infrastructures resilience along their service life cycle.