UCL Department of Civil, Environmental and Geomatic Engineering


Scour around the foundations of marine structures

Offshore wind farm arrays are being constructed in countries all around the world to meet the unprecedented expansion in demand for renewable energy.

20 September 2017

In the UK, arrays of wind turbines are being built in deeper waters, at sites where the structures are based on complex soils, and where they are required to operate under extreme environmental conditions. The design of foundations for the wind farms developed for these locations is presenting a series of new challenges.

Working closely with industry, researchers in the CEGE Coastal Group are carrying out a series of investigations to understand and predict how seabed sediment is scoured from around the foundations of wind turbine support structures. This is of critical importance in the design process, because excessive scour can lead to structural failure, whilst conservative design can add massively to costs.

Recent projects have examined the effects of waves and currents on different forms of marine foundation in a variety of seabed sediments under a range of environmental conditions. This work has led to:

  • publication of a new formula which allows designers to predict the scour around marine structures with complex geometries such as gravity-based structures which are suitable for deployment in deeper waters
  • identification of conditions under which scour in mixed or layered sediments can exceed the values predicted by conventional design methods
  • measurement of changes in scour depth through a full spring-neap tidal cycle and in the presence of combined waves and currents
  • identification of the effects of structural vibration on the depth of scour in cohesive and non-cohesive sediments and on the performance of scour protection.

The CEGE Coastal Group’s research into seabed scour around marine structures is helping designers to understand the effects of waves and currents on foundations with complex shapes. This will help to improve design procedures, particularly in the UK, where wind farms are being built in deeper waters, at sites which are often subject to extreme environmental conditions.