Lifetime seismic damage evolution and resilience assessment of offshore bridges under height-varying corrosion and scour

• Published in: Ocean engineering Vol. 326; p. 120883
• Main Authors: Su, Junsheng, Li, Jiajun, Wu, Dianqi, Lu, Guanya, Wang, Li, Ma, Jiaxing, Li, Zhong-Xian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.05.2025
• Subjects: Damage evolution; Height-varying corrosion; Lifetime; Offshore bridges; Resilience assessment; Scour; Offshore bridges; Lifetime; Height-varying corrosion; Damage evolution; Scour; Resilience assessment
• ISSN: 0029-8018
• DOI: 10.1016/j.oceaneng.2025.120883

A typical offshore two-span RC bridge is selected to develop a time-variant finite element model (FEM), considering height-varying corrosion degradation and foundation scour. Using the damage index that accounts for time-varying degradation, seismic fragility analyses were conducted to evaluate the lifetime seismic damage evolution and seismic resilience. Analysis results indicate that, during the early phases of service, height-varying corrosion slightly decreases seismic fragility of RC piers rather than increasing it, as it mitigates the concentration of damage at the pier bottom. However, the damage transfers from pier bottom to the tidal and splash regions as time progresses, resulting in continuous increase in seismic fragility of substructure and subsequent reduction in resilience of bridge system. On the other hand, foundation scour exacerbates damage to the piles, thereby increasing seismic fragility of the entire bridge substructure during the early service stage. However, over long-term service, foundation scour ultimately reduces seismic fragility and enhances the seismic resilience of the bridge substructure. This occurs because intensified pile damage from increased scour depth helps to alleviate damage concentration in the tidal and splash regions of pier, leading to a more balanced distribution of damage between pier and pile and ultimately improving seismic resilience. •Conduct time-dependent fragility analysis of an offshore bridge accounting for height-varying corrosion and scour.•Propose a curvature-based, time-varying degradation damage index for RC piers.•Provide a novel insight into seismic damage transfer between bridge piers and piles under long-term service.•Reveal effects of height-varying corrosion and scour on lifetime seismic resilience of offshore bridges.