Performance and bearing behavior of monopile-friction wheel foundations under lateral-moment loading for offshore wind turbines

Abstract

The hybrid foundation of combining a friction wheel with a monopile is an innovative solution for offshore structures subjected to large lateral-moment loading. In this paper, the lateral-moment response of the monopile-friction wheel foundation in saturated sand are investigated via centrifuge tests and three-dimensional finite element method (FEM). A series of tests on the monopile, hybrid foundations with wheels of different diameters and thicknesses, and single wheel foundation were conducted. The results show that the lateral bearing capacity and stiffness improve significantly by adding a wheel to monopile, and the improvement follows the diameter or thickness of the wheel. An extensive experimental research regarding to the influential factors such as the embedment of the wheel and the vertical load is also presented. By means of FEM, the load transfer mechanism, interaction between the foundation and soil, and the bending moment in the pile are illustrated to study how the wheel contributes to the performance of the foundation system. Moreover, the effects of load eccentricity and vertical load are investigated by FE analyses.