Stochastic modelling of wind and wave induced loads on jacket piles

Support structures for offshore wind turbines are loaded by wind and waves. In deeper water so-called jacket substructures are used, which use driven piles as foundations. In around 40 m water depth and for wind turbines of the 5MW class, these piles are approximately loaded equally by wind and waves.
This paper presents investigations into the superposition of the stochastic processes wind and waves. The response statistics due to turbulent wind loading are analysed in detail. For stochastic wave loading a method is given which allows for the consideration of the nonlinearity of large waves in the time domain. A simple approach to determine design loads for combined wind and wave loading is outlined at the end of this paper.