ACP TR-2-2025 Cyclic Degradation in the Geotechnical Design of Wind Turbine Foundations Technical Report

The draft Technical Report reviews the behavior of foundation support geomaterials under cyclic loading for various onshore wind turbine foundation types and highlights the importance of design to limit geomaterial degradation.

The report is motivated by the need to ensure satisfactory foundation performance during service life particularly when the foundation-geomaterial interface is subjected to a high number of cycles between compression and zero loading. Load cases are discussed with reference to the ACP 61400-6 standard.

Design recommendations for different foundations and soil types are provided. General guidance is also provided for laboratory testing, numerical modelling, in-service monitoring, and issue mitigation.