Offshore Foundation Based on the ELiSE Method

Abstract

Within the framework of the BIONA-project “Offshore Foundation based on ELiSE procedure” (OFE), we developed a weight-minimized steel foundation for offshore wind energy power plants. These foundations are almost 50 m high and have to cope with very strong forces and moments which arise due to gravity and wind as well as currents and waves. Since the current solutions are still relatively heavy, expensive and difficult to build, the aim of OFE was to develop a lighter, cheaper, and structurally simple solution. In this project we applied the bionic method “Evolutionary Light Structure Engineering” (ELiSE), which uses structural lightweight solutions of unicellular planktonic organism. Associated with this was the necessary transfer of structures from the µm to the meter size range, the necessity to find adequate structural models, a change of material, adaptations to different load cases and a strong simplification of the design. Clearly, this is an ambitious task for a bionic development. In this chapter we show that (a) within the ELiSE procedure, radiolarians have a high potential to serve as natural models to minimize the weight of foundations (b) scaling was possible even though the length scale was increased by a factor of 10⁶, (c) the change of materials from biogenic silica to steel was possible, and (d) even radically simplified bionic geometries can improve existing offshore foundations significantly (weight reduction > 40 %). In addition, our results show that a combination of suitable archetypes and optimization tools, such as genetic algorithms, is a powerful tool to develop efficient, unconventional lightweight designs.