Design of Foundations for Offshore Wind Turbines

6Simplified Hand Calculations

Learning Objectives

1. The aim of this chapter is to carry out hand calculations relevant to different aspects of foundation design based on methods presented in Chapters 2 and 5.
2. It is often necessary to cross‐check high‐fidelity finite element calculations. The methods presented in the chapter can be used for such purposes.
3. For financial viability of a project, a quick estimation of the sizes of the foundation are needed without the recourse to expensive numerical modelling. The calculations presented in this chapter will be helpful for such purpose.

6.1 Flow Chart of a Typical Design Process

It is often necessary to take a bird's‐eye view of a design process highlighting the different ingredients. Figure 6.1 shows a typical flowchart of a foundation design.

Figure 6.1 Flowchart of a design process.

As may be observed, the main ingredients for foundation design are:

1. (a) Loads on the foundation under different scenarios
2. (b) Site investigation, i.e. ground conditions
3. (c) Criteria for design

This chapter provides the following examples:

1. Target frequency of a turbine
2. Stiffness of a monopile foundation using three types of method: simplified, standard, and advanced methods
3. Stiffness of a mono‐caisson
4. Estimation of loads on a monopile foundation through the use of spreadsheet type program
5. Natural frequency of a monopile‐supported wind turbine ...