Development of a semi-structured database for back-analysis of the foundation stiffness of offshore wind monopiles

Abstract

Offshore wind turbines founded on monopiles are highly dynamic structures in which the stiffness of the soil adjacent to the monopile controls the natural frequency of the structure. As the loading regime and ground conditions surrounding the foundation are subject to considerable uncertainty, adaptable digital twins of the offshore structures are valuable as they allow the use of in-field monitoring data for model updating. As soil conditions and water depths are rarely uniform across a wind farm site, each structure is expected to behave differently. To back-analyse structural performance, geotechnical and structural data needs to be retrieved at every foundation location. A serverless cloud-based application was developed to allow quick and reliable storage and retrieval of geotechnical and structural data. The database was combined with an API layer to allow parametric data retrieval for back-analyses and digital twin updating across an entire wind farm. As the web application is hosted in the cloud, the data can be accessed through simple HTTP requests by authenticated users working offshore, in the office or remote. The performance of this solution is illustrated with a case study in which foundation stiffness across an entire wind farm site is parametrically calculated and updated.