A huge increase in the size of wind turbines being installed and a move to installations in deeper water have led to the design and installation of huge subsea structures.
One location for such installations is the Trianel Wind Farm Borkum West II, situated 45 km off the German coast. Its huge steel tripod bases each have to support a combined tower and nacelle weight of over 500 tonnes.
Connecting the tripod bases by way of bolted flanges almost 6 m in diameter is a huge task and as critical as any part in the offshore wind installation process. In particular, achieving the required bolt design tension and clamping force to ensure structural stability is paramount to the security of the wind turbine.
James Walker RotaBolt® tension measurement fastener technology is being used on the project as a reliable method of achieving the design clamp load for these flanges.
Each RotaBolt fastener’s locking cap technology provides an accurate measurement and a visual or tactile indication that the required design tension has been achieved and is being maintained.
Under the lead management of Trianel GmbH, 33 municipal and regional energy supply companies are involved in the construction of Trianel Wind Farm Borkum West II. The installation will eventually have 80 Areva MultiBrid M5000 turbines, delivering a total of 400 megawatts.