OFFSHORE WIND TURBINE FOUNDATIONS - THE COWI EXPERIENCE

摘要

This paper presents the experience gained and the lessons learned over the last decade within the numerous offshore foundation projects undertaken by COWI in European waters. This experience derives from the close collaboration with, and interaction between the owners, contractors, and engineers in the various stages of project development. In turn, the experience draws on COWI's vast experience within foundation of large bridges world wide over half a century. Focus is on two pioneering gravity base foundation projects: 1. Nysted in Denmark, currently the largest offshore windfarm worldwide with 72 Nos Bonus 2.3 MW turbines in water depths up to 10 m in the relatively benign inner Danish waters2. Thornton Bank in Belgium, where the first phase -comprising 6 Nos Repower 5MW-turbines of a total of 60 - are planned to be built in the rough North Sea in water depths exceeding 25 m. The two projects illustrate the speed at which the structural concept must keep pace with increases in turbine size. The projects exemplify how a tailor made design is made fit for purpose. The latter case uses state-of-the-art designs for thin-walled reinforced concrete shell structures.