A time-variant non-probabilistic reliability assessment strategy for laterally loaded offshore monopiles under scour and corrosion

The reliability of monopiles is paramount for the uninterrupted operation of offshore wind turbines. However, this reliability is often challenged by environmental factors, such as scour and corrosion, as well as the inherent uncertainty in loads, soil properties, and environmental variables. Therefore, this study proposes a time-variant non-probabilistic reliability assessment strategy for laterally loaded offshore monopiles under scour and corrosion. This strategy is grounded in non-probabilistic interval and interval process models, along with a lateral response analysis of soil-pile system that accounts for the effects of scour and corrosion. The time-variant reliability index is determined using an enhanced HL-RF algorithm. The application of this method to specific cases of laterally loaded monopiles under scour and corrosion demonstrates its remarkable feasibility and adaptability, even for high-dimensional uncertainty scenarios. Furthermore, a sensitivity analysis, based on the proposed strategy, enables the identification of uncertain parameters that significantly impact monopile reliability, providing valuable insights for practical engineering applications. Additionally, this framework has the potential to be extended for a more comprehensive evaluation of the fatigue characteristics of offshore monopiles, an area that merits further exploration.