Investigating the effects of slope changes of asphaltic concrete core of rockfill dam on the fragility curves

Asphaltic core rockfill dams (ACRDs) are increasingly utilized due to their self-healing properties and construction advantages, yet their seismic performance, particularly with inclined cores, remains underexplored. This study aims to investigate the influence of asphaltic core inclination on the seismic fragility of ACRDs, using the 84-meter Shur dam in Iran as a case study. Three core configurations of vertical, partially inclined, and fully inclined were modeled using FLAC 2D software, with peak ground acceleration (PGA) as the intensity measure and relative crest settlement ratio as the damage measure (DM). Incremental Dynamic Analysis (IDA) was employed, involving 450 finite difference simulations with 15 seismic records scaled from 0.1 g to 1.0 g. Fragility curves were derived to assess the probability of minor, moderate, and severe failure states. Results indicate that core inclination significantly reduces crest settlement and failure probabilities, with the fully inclined core showing the best performance (e.g., 0% severe failure probability at 0.8 g PGA compared to 41.1% for the vertical core). These findings align with ICOLD recommendations and highlight the potential of inclined cores to enhance seismic safety. This study provides actionable insights for designing ACRDs in high-seismicity regions, emphasizing the benefits of inclined core configurations to improve resilience and reduce retrofitting costs.