Un- and reloading stiffness of monopile foundations in sand |
| |
| Institution: | 1. Institute for Geotechnical Engineering, Leibniz University Hannover, Germany;2. ACP Grundbauplanung GmbH, Hannover, Germany;1. School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin, 300401, PR China;2. Department of Civil Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA;1. Norwegian University of Science and Technology, Department of Civil and Transport Engineering, Hogskoleringen 7A, 7491 Trondheim, Norway;2. SINTEF Building and Infrastructure, SINTEF, Trondheim 7034, Norway;1. Chair of Soil Mechanics, Foundation Engineering and Environmental Geotechnics, Ruhr Universität Bochum, Germany;2. Chair of Geotechnics, Bauhaus Universität Weimar, Germany;3. Institute for Geotechnics, Technische Universität Darmstadt, Germany;4. Chair of Soil Mechanics and Geotechnical Engineering, Brandenburgische Technische Universität Cottbus-Senftenberg, Germany;1. Queen''s School of Engineering, University of Bristol, BS8 1TR, UK;2. Department of Civil and Environmental Engineering, University of Surrey, GU2 7XH, UK |
| |
| Abstract: | The eigenfrequency of offshore wind turbine structures is a crucial design parameter, since it determines the dynamic behavior of the structure and with that the fatigue loads for the structural design. For offshore wind turbines founded on monopiles, the rotational stiffness of the monopile-soil system for un- and reloading states strongly affects the eigenfrequency. A numerical model for the calculation of the monopile’s behavior under un- and reloading is established and validated by back-calculation of model and field tests. With this model, a parametric study is conducted in which pile geometry, soil parameters and load conditions are varied. It is shown that of course the rotational stiffness varies with mean load and magnitude of the considered un- and reloading span, but that for most relevant load situations the initial rotational stiffness of the monopile system, i.e. the initial slope of the moment-rotation curve for monotonic loading, gives a good estimate of the actual stiffness. Comparisons of different p–y approaches show that the ordinary API approach considerably underestimates the initial stiffness, whereas the recently developed ‘Thieken’ approach and also the ‘Kallehave’ approach give a much better prediction and thus might be used in the design of monopiles in sand. |
| |
| Keywords: | Monopile Stiffness Eigenfrequency Un- and reloading Offshore wind |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
