Abstract

Offshore wind turbines offer promising alternative of harnessing the wind power in coastal regions where high population density and associated economic and social factors obstruct use of suitable sites on land. High construction and grid connection costs of the offshore facilities are offset by the higher quality of wind resources over sea and the installation of large capacity turbines which, consequently, result with higher and cheaper energy production.

Despite the advances and developments of quick and efficient offshore installation procedures market pressures to reduce turbine cost and increase of long-term reliability continue unabated. This particularly applies to the cost of supporting structure which may account for up to 30% of the total cost of the offshore facility. With the rising price of steel in response to the construction boom around the world there is a desire on the part of generation companies to diversify wind turbine construction market by improving massive concrete gravity support structures.

This presentation discusses geotechnical challenges associated with the construction and operation of concrete gravity support structures. Various aspects of the engineering design are discussed: scour protection, seabed stability, limit state based optimisation of the support structure and the effect of supporting structure on the dynamic properties of a wind turbine.