Concrete gravity dams, forming a quarter of the ICOLD database with over 61,000 dams, often surpass 50 years of service, necessitating increased maintenance and safety scrutiny. Given the aging and advancing seismic safety methods, reevaluating their seismic resilience, considering material degradation and concrete heterogeneity, is imperative. This study conducts a comprehensive seismic fragility assessment of the Pine Flat Dam at lifecycle stages of 1, 50 and 100 years, accounting for material degradation due to aging and uncertainties from concrete heterogeneity. It develops a 2D dam-foundation-reservoir model with fluid-structure-soil interaction and material nonlinearity using the concrete damage plasticity model. The assessment includes 55 ground motions, selected via the conditional mean spectrum method, representing five return periods from 475 to 10,000 years. Fragility curves are developed by fitting a lognormal distribution to failure probabilities at varying intensities. These curves are compared using damage indices like crest displacement and stress at the dam's neck and heel. Aging increases failure probability, correlating with age and return period, as shown by the leftward shift of fragility curves, while concrete heterogeneity adds uncertainty. The results emphasize the critical need for ongoing seismic fragility reassessments, accounting for aging, environmental exposure, and seismic demands on dam safety.

来源平台：STRUCTURE AND INFRASTRUCTURE ENGINEERING