Jacket Type Wind Turbine Foundation and Methods for Construction Thereof

A jacket type wind turbine foundation (jacket) for supporting a wind turbine tower, wherein the jacket comprises:

• a jacket support structure configured to transfer loads from the tower to a seabed, wherein the jacket support structure comprises legs supported by a bracing system built of cross members;
• and
• a transition piece constituting a top part of the jacket, wherein the transition piece is configured to transfer the loads and weight of the tower to the jacket support structure,
• wherein the legs are bolted to the transition piece, wherein the transition piece comprises:
• a floor;
• a centrally arranged entrance arranged and configured to allow access to the transition piece for staff and/or equipment;
• and
• one connection portion for each of the legs, wherein each connection portion is attached to one of the legs by a joint,
• wherein the joint is arranged at a level below a level of the floor of the transition piece, wherein the transition piece comprises one or more cast transition piece segments, wherein the entrance is an opening provided in the floor of the transition piece.

A method for constructing a jacket type wind turbine foundation (jacket) for supporting a wind turbine tower, wherein the method comprises:

• providing a jacket support structure configured to transfer loads from the tower to a seabed, wherein the jacket support structure comprises legs supported by a bracing system built of cross members;
• providing a transition piece constituting a top part of the jacket, wherein the transition piece is configured to transfer the loads and weight of the tower to the jacket support structure, the transition piece comprising:
• a floor;
• a centrally arranged entrance arranged and configured to allow access to the transition piece;
• and
• one connection portion for each of the legs;
• and
• attaching each of the connection portions to one of the legs via a joint,
• wherein the joint is arranged at a level below a level of the floor of the transition piece, wherein the transition piece comprises one or more cast transition piece segments, and wherein the entrance is an opening provided in the floor of the transition piece.