Collapse fragility curves of RC piers with corroded rebars

Ageing and deterioration of Reinforced Concrete (RC) bridges can significantly increase their seismic vulnerability and have a significant impact on expected economic losses. In this study, the seismic performance of typical single-shaft piers with corroded rebars is examined through extensive Multi-Stripe non-linear response time-history Analyses (MSA). Piers with different cross sections and heights, featuring different deterioration scenarios, characterized by different corrosion patterns and severity levels of corrosion, are investigated. MSA are performed using twenty pairs of ground motion records consistent with the seismic hazard of the cities of L’Aquila (central Italy) and Naples (southern Italy), for nine different earthquake intensity levels with return periods ranging from 50 to 100.000 years. Lognormal fragility curves associated with pier collapse are derived to account for record-to-record variability. Finally, the annual failure rates associated with collapse are derived to evaluate the structural reliability of each model both in the as-built and deteriorated conditions.