Performance of monopile-friction wheel foundations under lateral loading for offshore wind turbines

The new type of foundation which comprises a monopile and a friction wheel is an innovative solution for offshore structures subjected to large lateral loading and has not been extensively investigated. In this paper, two types of friction wheels, namely the solid wheel and gravel wheel, are integrated to a monopile respectively to perform as hybrid foundations. The hybrid foundations are examined under lateral loading via centrifuge tests and three-dimensional finite-element (FE) analysis. The results show that the introduction of the wheel significantly enhances the lateral bearing capacity and stiffness of the monopile. By means of FE analysis, the load transfer mechanism and interaction between the foundations and soils are illustrated to study how the solid wheel and gravel wheel contribute to the performance of the foundation system. Finally, parametric studies about the geometry of the foundations and loading conditions are carried out, which can be used as references for the preliminary design of the monopile-friction wheel foundation.