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Title: Simplified design of offshore wind turbine jackets supported on multiple foundations incorporating soil-structure interaction
Author: Jalbi, M. Saleh
ISNI:       0000 0004 8503 1876
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 2019
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Foundations are one of the most expensive items in the capital cost break down of an offshore wind farm and the design is a challenging and multidisciplinary task that requires an understanding of the aerodynamics, hydrodynamics, structural dynamics, and soil-structure interaction. Though there has been extensive research, foundation codes are still not fully developed and are heavily dependent on the principles developed for oil & gas platforms which have distinct differences with offshore wind installations. Furthermore, current offshore wind turbines are becoming larger in size and installed in deeper waters, thus jackets are becoming a more attractive option when compared to the conventional monopiles. However, the current design methods for jackets are computationally challenging and time consuming, and often is the case, require data that is unavailable in the public domain which makes concept designs a difficult process. Due to the lack of simple integrated approaches, this thesis focuses on developing an integrated and modular design approach which can be easily implemented on spreadsheet type software and result in a conservative foundation size with adequate accuracy. The design criteria covered in this thesis are the Ultimate Limit State (ULS), Serviceability Limit State (SLS), and the natural Frequency requirements. For the dynamic analysis of foundations, a novel approach is proposed that expresses the natural frequency of the system in terms of mechanics based approaches considering the flexibility of the jackets and supporting foundations. The analysis steps from the thesis are compiled into an integrated design approach applied to jackets and their supporting foundations named as the "10-step method". It is shown that following these steps will result in a similar jacket and foundation size as detailed designs. The approaches of this thesis are expected to be a very powerful tool in the concept design stage when the financial viability of a wind farm is assessed. The work of this thesis also sets "templates" of appropriate jacket and foundation sizes in the detailed design stage. Finally, future works and enhancement to the work of this thesis are also provided.
Supervisor: Bhattacharya, Suby ; Cui, Liang Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral