Ultimate state design of a deep water offshore wind turbine support structure for the central Mediterranean region

Abstract

The modem trend for offshore wind turbine design Is to maximize wind turbine size while minimising support structure costs. To achieve structural Integrity for such a design whilst maintaining project feasibility, the design approach necessitates consideration of both static and dynamic engineering design approaches. In this study an ultimate state design process In compliance with standard regulations for design Is presented. The design Is carried out for an offshore site having a 70m water depth In the central Mediterranean region. The design process Involves: a natural frequency analysis of multiple jacket structures, an ultimate state design of a selected jacket structure where structural Integrity was ensured through an Iterative process and a fatigue analysis where cost effectiveness between two possible engineering practices was studied. The study produces a Jacket design solution for a 5MW offshore wind turbine having a base width of 16 metres, top width of 10 metres, first mode natural frequency of 3 Hz and total weight of 600 tons.