Design of Foundations for Offshore Wind Turbines

3Considerations for Foundation Design and the Necessary Calculations

Learning Objectives

Wind turbine structures are subjected to dynamic loads and modes of vibration of these structures play a key role in design considerations. Therefore, the chapter starts with a section on modes of vibration. The chapter then discusses the design consideration guided by limit states: ULS (ultimate limit state), SLS (serviceability limit state), and FLS (fatigue limit state). Issues related to installation are also discussed. This chapter will also discuss the calculations that needs to be carried out the designers: Ultimate capacity of the foundation, natural frequency of the whole system, deflection, and rotation of the foundation. This also includes allowable rotation and deflection, long‐term tilting of the foundation, and allowable change in natural frequency of the whole system, installation of foundations including driveability and long‐term issues such as soil erosion (scour), tilt, etc. For the various sections, fundamental, theory, and methodology will be described along with some solved examples. References will be provided to existing textbooks and codes of practice.

3.1 Introduction

Offshore wind turbines are complex machines, and the structure is dynamically sensitive. Furthermore, these are located in challenging offshore environment and, therefore, there are several types of design considerations. Before the design considerations are described, it is important to highlight ...