Seismic fragility of corroded reinforced concrete highway bridges

Highway bridges play a crucial role in ensuring smooth and fast transportation system across the regions. During their service life, highway bridges experience structural deterioration due to fatigue as well as harsh environmental conditions, like chloride penetration, acid and sulphate attacks, carbonation, freezing and thawing, etc. Over the years, reinforced corrosion is considered as one of the major concerns associated with the performance degradation of ageing highway bridges. Reinforcement corrosion in concrete bridges, leads to reduction in the effective cross-sectional area of the steel, changes in material properties, lower bond strength between reinforcement bars and the surrounding concrete, spalling of concrete cover, loss of confinement, etc. With several catastrophic consequences over several decades, earthquakes are considered as one of the major natural hazards across the world. Consequently, this study aims at seismic vulnerability evaluation of corroded reinforced concrete highway bridges using three-dimensional nonlinear finite element modelling philosophy. The numerical simulation results of corroded reinforced concrete structural components are successfully validated with respect to the experimental results from the literature. Fragility functions represent the conditional probability of a structure surpassing a particular damage state under seismic excitations. Hence, time-dependent seismic fragility curves are derived for corroded reinforced concrete highway bridges using incremental dynamic analysis philosophy. Excerpts from the study would enlighten the researchers and practicing engineers about the seismic vulnerability of corroded reinforced concrete highway bridges across the world in a realistic manner.