Highway bridges exposed to harsh environmental conditions and located in active seismic regions shows a cumulative increase in earthquake induced damage along their service lives. While environmental degradation mechanisms are typically continuous throughout the lifetime, earthquake shocks are intermittent that depend on the seismicity of the region. Among the different aging mechanisms commonly observed in bridges, this study focuses on corrosion deterioration of critical bridge components such as bridge piers. Although past literature has underlined the impact of corrosion deterioration on seismic performance of the bridges, most of these studies are limited to single earthquake events. In reality, the bridges may be subjected to multiple earthquakes during their service lifetime. Minor structural damage from a relatively weak earthquakes may not be critical and need not require immediate repair but the damage accumulation in future events may be significant especially for aging bridges. This study proposes a framework that simultaneously considers multiple earthquake occurrences and corrosion Damage deterioration of bridge components in determining the damage accumulation throughout the service life. The performance of bridge structures due to past earthquakes and loss of seismic capacity due to corrosion deterioration is taken into account in predicting the damage accumulation index for future events. A representative case-study bridge located in California region is considered
in this study. Along with the statistical uncertainty associated with corrosion deterioration and occasional main-shock occurrence, uncertainty stemming from material properties is also considered in this study. An appreciable increase is observed in the cumulative damage index while considering the effects of corrosion deterioration when compared to pristine bridge structures.
Prof. Jayadipta Ghosh