2011 Geotechnique Lecture – Foundation Design for Offshore Wind Turbines
Dr Byron Byrne
The UK Government has put in place ambitious plans for energy generation from renewable sources for the next decade, and beyond. To achieve these targets a substantial contribution from offshore wind is required. At present there are just over one thousand offshore wind turbines installed and operating around the UK, with hundreds more currently being constructed and plans to build thousands more. Similar developments are expected in other countries around Europe and elsewhere in the world, such as offshore China. The foundation design is critical to the overall turbine design, influencing the structural layout, the turbine’s dynamic and fatigue response as well as the construction and installation approach. Not unexpectedly these all have significant effects on the overall project economics.
This lecture draws on work published in Géotechnique covering foundation design for offshore wind turbines. The lecture is split into two parts. The first half covers current foundation designs, concentrating on the response of monopoles, particularly to cyclic lateral loading. A framework for calculating accumulated rotations, based on small scale laboratory tests, will be described. The work has highlighted that the stiffness of the pile response can change with the number of cycles applied, an important consideration for the fatigue design. The second part of the lecture looks forward to new designs, concentrating on suction installed foundations (suction caissons), a promising alternative to piled foundations, but as yet unused for offshore wind turbines. A wide ranging programme of research at Oxford has explored caisson design, from stiffness of response through to ultimate capacity, and the key outcomes of the research will be presented.
Dr Byron Byrne is a University Lecturer in Engineering Science at Oxford University and a Tutorial Fellow at St Catherine’s College. After his combined degree in Civil Engineering and Commerce at the University of Western Australia, and a short period of industrial experience, he came to Oxford as a Rhodes Scholar, specialising in offshore foundations. He has held a prestigious 1851 Research Fellowship and a Fellowship by Examination at Magdalen College in Oxford. His research on soil- structure interaction is mostly applied to offshore engineering. He has published widely on foundations for offshore structures, particularly for offshore renewable energy, and also carries out research on offshore pipelines. His work has been supported by the industry, EPSRC, the Royal Society and the Government. A feature is the industrial involvement in his research and he is currently leading a Joint Industry Project aimed at developing new design guidance for laterally loaded piles for offshore wind turbines. He is active in providing advice to the industry. He has been a member of Géotechnique Advisory Panel and is currently a member of the Géotechnique Letters Advisory Panel.
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