Probabilistic Long-Term Resilience of Bridges under Seismic and Deterioration Processes

Accurate long-term risk and resilience assessment of bridges are of paramount importance to aid rational decision-making under seismic hazards. There exist time-varying features within both earthquakes and structural deterioration. It has been found that the occurrence of large earthquakes is dependent on time due to energy accumulation, whereas the widely adopted homogeneous Poisson process assumes the time-independent occurrence of hazards. Besides, bridges can deteriorate over time due to environmental exposure, resulting in increased seismic vulnerability. The time-varying characteristics associated with both earthquakes and deterioration, which cause compound effects to structures, should be incorporated in long-term seismic risk and resilience assessment. In this paper, an approach for assessing the long-term resilience of bridges incorporating time-varying characteristics of earthquakes and deterioration is proposed. The Brownian Passage Time (BPT) model capturing energy accumulation and release is used to model time-varying characteristics of earthquakes. The bridge seismic vulnerability is computed in a time-variant manner considering deterioration. Subsequently, long-term bridge resilience is computed by considering earthquakes and deterioration occurring during the entire service life of bridges. The proposed approach is illustrated on a highway bridge under time-dependent seismic hazard and structural deterioration.