Madsen, Søren1; Andersen, Lars Vabbersgaard1; Ibsen, Lars Bo1
1 Department of Civil Engineering, The Faculty of Engineering and Science, Aalborg University, VBN2 Division for Structures, Materials and Geotechnics, The Faculty of Engineering and Science, Aalborg University, VBN3 The Faculty of Engineering and Science (ENG), Aalborg University, VBN4 Geotechnical Engineering, The Faculty of Engineering and Science, Aalborg University, VBN
Using large suction caissons for offshore wind turbines is an upcoming cost-effective technology also referred to as bucket foundations. During operation, the monopod bucket foundation is loaded by a large overturning moment from the wind turbine and the wave loads. However, during installation the suction caisson is loaded by external pressure (internal suction) due to evacuation of water inside the bucket and vertical forces due to gravity. The risk of structural buckling during installation of large-diameter suction caissons is addressed using numerical methods. Initial imperfect geometries are introduced, based on the buckling mode shapes from a linear eigenvalue buckling analysis. Different imperfect geometries are introduced to reveal how sensitive the buckling load is to these imperfections. Including the first 21 mode shapes as imperfect geometries will reduce the buckling pressure compared to only considering mode 1. The results of the finite element analysis are compared with current standards for evaluating buckling loads.