Time-dependent Seismic Fragility Assessment for Aging Highway Bridges Subject to Non-uniform Chloride-induced Corrosion

• Published in: Journal of earthquake engineering : JEE Vol. 26; no. 7; pp. 3523 - 3553
• Main Authors: Li, Huihui, Li, Lifeng, Zhou, Guojie, Xu, Liang
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 19.05.2022; Taylor & Francis Ltd
• Subjects: Ageing; Aging; Bridge engineering; Capacity; Chloride; Chlorides; Comparative analysis; Comparative studies; Concrete columns; Continuous bridges; Correlation; Corrosion; Curvature; Deterioration; Ductility; Earthquake damage; Fragility; Girder bridges; Highway bridges; Mathematical analysis; non-uniform chloride-induced deterioration; Parameters; Reduction; Reinforced concrete; Seismic activity; Seismic response; Time dependence; time-dependent seismic fragility; variable correlation
• ISSN: 1363-2469; 1559-808X
• DOI: 10.1080/13632469.2020.1809561

This paper proposes an alternative time-dependent seismic fragility assessment framework considering the variable correlation of structural random parameters for aging highway bridges subject to non-uniform chloride-induced corrosion attacks. The proposed systematic framework is implemented to perform a probabilistic time-dependent seismic fragility assessment for a typical multi-span reinforced concrete continuous girder (MSRCCG) bridge. Effects of non-uniform chloride-induced deterioration on the time-evolving seismic capacity, seismic demand of reinforced concrete (RC) columns, and the time-dependent seismic fragility of the case-study bridge are investigated using nonlinear sectional moment-curvature and nonlinear time history analysis. Furthermore, this paper performs comparative studies to investigate the influence of variable correlation of structural random parameters on the time-variant seismic capacity, seismic demand of RC columns, and time-dependent seismic fragility of the case-study bridge. The results indicate the following conclusions: (1) Non-uniform chloride-induced corrosion may change the vulnerable position and the damage mechanisms of RC columns; (2) Due to non-uniform chloride-induced deterioration, the flexural capacity and curvature ductility of RC columns may exhibit a nonlinear reduction, while there is a nonlinear accelerated growth of time-dependent seismic fragility for aging highway bridges along their service lives; (3) The time-variant seismic capacity (i.e., the flexural capacity and curvature ductility) and seismic demand of RC columns tends to have a certain reduction and increase by ignoring the variable correlation of structural random parameters, respectively; and (4) The time-dependent seismic vulnerabilities of aging highway bridges may be overestimated by ignoring the variable correlation of structural random parameters.