Driven pile design for offshore wind jacket structures

Abstract

Offshore wind is becoming an established and affordable technology to mitigate climate change. The foundations, which can represent around 25% of the overall cost of the wind turbine and include some of the biggest installation risks, remain an area of particular interest for cost reduction. Most foundations installed to date have been monopiles in relatively shallow waters; however, to tackle the challenges of increasing water depths and turbine sizes, alternative solutions are required. This paper highlights key aspects of driven piles design for the foundations of steel jacket structures, to support wind turbine generators (WTGs). Some specific aspects of driven pile design such as the benefits of CPT-based pile design methods, practical means of assessing the impact of cyclic loading, the importance of soil structure interaction on natural frequency and the distribution of loads in the structure are covered. The benefits of an integrated geotechnical and structural approach to enable standardisation across variable ground conditions and water depths are emphasised.