Analysis of Grouted Connection in Monopile Wind Turbine Foundations : Analytical Assessment of Deflections, Strains and Stresses in Grout

Grouted connections are highly utilized in the expanding offshore wind energy generation industries, providing a very efficient method for connecting foundation substructure to the tower of an offshore wind turbine. Offshore wind turbines are primarily exposed to overturning moment, arising from both the aerodynamic and hydrodynamic sources. So far, no design standard provides analytical methods to account for this kind of load transfer through the grouted connection. The intention of this paper is to demonstrate that analytical estimations can be formulated that reasonably agree with both experimental and numerical analyses of such connections. It is based on a theoretical approach, involving both theory of elasticity and finite element methods. The analytical approach involves various aspects of vector calculus, boundary value problems, potential energy formulations, harmonic functions and solution methods for 1, 2 and 3-dimmensional systems of equations. The finite element approach involves theoretical background on general FE formulations, solution methods, boundary definitions and contact problems.