Abstract
One of the major concerns of designing offshore wind turbine foundations is to address the effects of cyclic loading coming from, especially, wave loading. This paper describes the results from a test series on a small-scale mono bucket foundation installed in water-saturated dense sand exposed to cyclic loading with 1.0 Hz. A macro model has been calibrated to fit the test results, and it has been shown that the load frequency has a major influence of the measured rotation of the foundation. Compared to previous tests, the presented test program has been conducted under partly drained conditions due to a higher load frequency, and in addition the foundations have been preloaded by cyclic loads simulating small wave impacts prior to major storm events. The calibrated model shows, in contradiction to previous findings for drained conditions, that two-way loading leads to the largest rotations of the foundation. The reason for this is the partly drained or undrained soil response during testing. The paper also presents a cyclic load response diagram, which is a tool to be used in a predesign of a mono bucket foundation. The diagram gives the designer a quick overview of the cyclic load response and the effect of increasing or decreasing the foundation size.
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Acknowledgments
The authors would like to acknowledge The Danish National Advanced Technology Foundation project “Cost-effective deep water foundations for offshore wind turbines,” which funded this project.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 143 • Issue 11 • November 2017
Copyright
©2017 American Society of Civil Engineers.
History
Received: Feb 19, 2016
Accepted: May 30, 2017
Published online: Sep 14, 2017
Published in print: Nov 1, 2017
Discussion open until: Feb 14, 2018
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