Longitude was instructed by Rampion Offshore Wind to investigate the causes of monopile oscillation during the pile lowering operation experienced on site. The aim of the analysis was to understand the nature of the oscillation and then predict the relationship between pile dimensions and environmental conditions that could lead to unacceptable oscillations. Numerical modeling validated with both model and full-scale measurements gave the Developer and Installation Contractor (MPI) increased operability allowing the challenging installation schedule to be met.
Longitude’s Scope of Work
- Model the full instillation scenario in OrcaFlex
- Develop scripts to process large batches of piles, conditions and seed numbers to give statistically useful results
- Support the development of a control system for dynamic tugger winches to damp pile oscillation
- Support model tests and full-scale pile motion measuring to validate numerical model
- Interface with developer, contract and Marine Warranty Surveyors to ensure practical operational limits could be set
The output of the analysis was a spreadsheet tool for use onboard and ashore to allow detailed combinations of environmental conditions including wind wave, swell, wind and current to determine the likely maximum oscillation. This gave a much larger window of operability compared to the previous blanket exclusion of certain wave periods.