Global Warming and Its Implications for Seismic Fragility and Risk Assessment of RC Bridges Affected by Chloride Ingress and Aging

Given that modern RC structures are expected to last much longer than 50 years, understanding how climate change impacts the service life of RC structures holds utmost significance. Recent research on climate change has shown that global warming is causing the atmospheric temperature and relative humidity to change gradually over time. The coastal RC infrastructure is experiencing degradation, attributed to climate change–induced rises in temperature and humidity. These environmental changes foster the corrosion of steel reinforcement. For marine RC bridges situated in regions with moderate to high seismic activity, the combined effects of these factors, exacerbated by chloride ingress, require meticulous attention. This study presents a comprehensive approach to develop an enhanced framework for assessing the time-variant seismic fragility and risk of aging bridges, taking into account the impact of changing climatic conditions. The suggested approach encompasses diverse elements, including the impact of evolving climatic conditions on the initiation and progression of corrosion, the inclusion of an advanced corrosion rate that varies with time, the analysis of seismic vulnerability for an aging RC bridge, and the amalgamation of different deterioration mechanisms associated with corrosion, changes in the climate, and earthquake risks. The application of the model to a chloride-affected RC T-girder bridge revealed that the impact of climate change may worsen the performance of the aging bridge structure under a seismic event. Subsequently, the outcomes obtained from seismic fragility and risk analysis provide valuable insights into the seismic vulnerability of bridges in marine environments under multiple hazards. The results can be utilized to develop suitable maintenance strategies that aim to ensure the adequate safety and serviceability of the bridge infrastructure system throughout its intended service life.