Numerical Evaluation of Hybrid Foundation Efficiency for Offshore Wind Turbines

Abstract This study explores the potential of hybrid foundation systems to enhance the performance of offshore wind turbine (OWT) monopile foundations, which are subject to significant cyclic loading over their operational lifetime. The dynamic nature of the seabed surrounding monopile foundations can lead to permanent deformations, compromising their stability and performance. Since replacing existing monopile foundations is impractical, hybrid foundation systems have emerged as a promising retrofitting solution. This research systematically reviews hybrid foundation configurations from existing literature and presents a numerical investigation of a novel hybrid system combining a monopile, a bucket foundation, and a steel circular hollow container reinforced with stiffeners and filled with a filling material. The results show that hybrid foundations significantly improve foundation stiffness, lateral load capacity, and moment resistance, while mitigating excessive tilting induced by cyclic wind and wave loads. These improvements enhance the structural stability, long-term reliability, and operational lifespan of OWTs. The findings demonstrate that hybrid foundations offer a viable and effective solution for retrofitting existing monopile foundations, ensuring better performance under environmental loading and contributing to the sustainability of offshore wind energy infrastructure.