QC Management, QC Engineering and site supervision during construction of 5 Transition Pieces (TP’s).
Weldmij provided support in QC Management, QC Engineering, and site supervision during the construction of five transition pieces for the Blyth Project. Each steel foundation is 6,5 to 7 metres in diameter, 2 x 30 metres in length and weights around 2 x 300 tonnes.
Steel foundation (TP’s) are usually produced in one piece, but in the case of Blyth, each TP is comprised of two parts. For this project, a complete construction would be impossible to lift it into place, once in the UK.
For completion of the full steel foundation, the upper section of 30 metres length was lifted with cranes above the lower section of 30 metres, assembled with strict tolerances, and welded together from inside and outside.
What makes the Blyth project so innovative is that the transition pieces (TPs), the tubes on which the wind turbines will ultimately be positioned, will not be driven into the ground. They will be secured in enormous concrete containers, called caissons, which have a diameter of around 31 metres. The caissons will remain in place by the placement of sand ballast within the caisson and shaft once they are positioned on the seabed.
The upper part of the transition piece that will actually be above sea level, is equipped with additional steel structures such as a boat-landing, ladders and platforms. These allow the owner to do maintenance and survey, but are also used during the installation of the foundation. The TP is exposed to heavy marine environment and for this reason equipped with corrosion protection for the entire structure.
Above the transition piece, the tower will be installed with the nacelle, a so called wind turbine generator with all the functional equipment that will generate power. This power will eventually be transferred to shore through large cable’s under the seabed.