Cyclic loadings of offshore wind turbine monopiles
Duration: 46 months (2017 - 2020)
Today, bottom-fixed wind turbines represent the most mature offshore renewable energies technology. The foundation of a bottom-fixed wind turbine represents 15 to 20% of the total investment and no regulated framework exists for questions of design. Strong constraints for energy efficiency imply a constant increase in turbine power and directly impact foundation design where installation and operating efforts are supported (high rotor frequencies and waves cyclic stress).
- Too propose recommendations for predicting the effects of lateral cyclic loading on soil-structure interaction in the case of a rigid pile
- To characterise the behaviour of the cement-concrete interface
- Creation of an experimental reference database including the results of centrifuge tests and analysis of the behaviour of the monopile under cyclic transverse loading in dense sand
- Experimental and rheological characterisation of the mechanics of chalk and the cement-chalk interface
- Comparison between the obtained stresses and the normative application recommendations, definition of a new methodology for a scale 1 pile
- Consideration of the change in ground conditions due to the installation, calculation of displacements and forces on flexible and rigid piles according to the loading cycles
The tools developed make it possible to better take into account the restructuring of the soil following the effect of pile driving in sandy soils, as well as the evolution of the parameters influencing the soil-structure interaction. The project also made it possible to develop a design procedure for rigid monopiles under transverse cyclic loading. A behaviour law for carbonate soil and its interaction with cement extends the scope of application.
Partners and funding
This project was led by Ecole des Ponts ParisTech and France Energies Marines.
The total project budget was €998K.
This project received funding from France Energies Marines and its members and partners, as well as French State funding managed by the National Research Agency under the Investments for the Future Programme (ANR-10-IEED-0006-18).
Photo credit: Fill / Pixabay