A joint offshore wind industry initiative has been launched to investigate the effect of increased monopile foundation size on the stability of the structures is underway.
The €3m Verification of Buckling Assessment and Behaviour in Large Monopiles (Verbatim) project is due to be completed by early 2023 and is investigating the potential pile-tip buckling phenomena during installation and buckling instabilities of the embedded pile near the mud-line.
Objectives include conducting analysis of conditions for pile buckling, developing and validating a finite element model and benchmarking study, and developing a design procedure for pile embedment and stability checks.
It also aims to optimise pile design, consider economic and ecological aspects and develop technical design rules for piles.
The work is being conducted by BAM, German’s Federal Institute for Materials Research and Testing, the Technical University of Berlin and JBO with support from the Carbon Trust.
“Increasing understanding of how monopiles behave during installation, and the potential defects that may reduce the lifetime of an offshore wind asset, could result in reduced wall thickness allowing safe, optimised structures, whilst also lowering costs,” the project’s participants said.
BAM project coordinator Matthias Baessler said: “As turbine size and water depths increase, the dimensions of monopile foundations continue to grow and we are now dealing with diameters of 10 metres or more.
“To install them safely and cost-efficiently we need verified calculation models. Therefore, in Verbatim we are specifically investigating the conditions for pile buckling.”
Carbon Trust project manager for Verbatim James Sinfield said: “The Verbatim project comes at an important time for the offshore wind industry.
“With monopiles becoming ever larger, we need to ensure that turbines are installed on solid foundations; the involvement of the Offshore Wind Accelerator partners in this project will ensure that the impact of the results are maximised and that new guidelines and best practice will be implemented quickly.”
The majority funding for the project is coming from the German Federal Ministry of Economics and Energy.
Verbatim also further benefits from strong technical and financial industry support provided by the Offshore Wind Accelerator partners – EnBW, Equinor, RWE, Orsted, Scottish Power Renewables, Shell and Vattenfall.