A Literature Study on the Effects of Cyclic Lateral Loading of Monopiles in Cohesionless Soils

Today, monopiles are the most typical foundation for offshore wind turbines. During their lifetime large diameter, stiff piles are subjected to millions of small cyclic loads due to environmental forces. The long-term cyclic loading can change the granular structure of the soil surrounding the pile. This may change the stiffness of the soil-pile system and create an accumulated rotation of the pile. The behaviour of the soil-pile system is very complex and the influence of soil parameters, number of load cycles, and size, amplitude and characteristic of the load are examined, as they all contribute to the rotation an the change in stiffness. The scope of this article is to outline current design methods and the state of the art knowledge within the subjectof long-term cyclic, lateral loading of piles