ABSTRACT
For modern offshore wind turbines several types of foundations exist. The choice of foundation depends on site and loading conditions. An often used foundation concept is monopiles, which are single steel pipe piles driven open-ended. Recently installed monopiles have diameters of 4-6 m and slenderness ratios, L/D, around 5, where L is the embedded length of the pile and D is the pile diameter. The maximum forces acting at the mudline of a foundation for a typical offshore wind turbine is according to Ubilla et al. (2006) in the order of magnitude of 4 MN in horizontal load, 6 MN in vertical load, and 120 MNm in overturning moment. Hereby, offshore wind turbine foundations are highly subjected to lateral loads and bending.
