Support structure for use in the offshore wind farm industry

Abstract

A support structure for use in the offshore wind farm industry, and a method of manufacturing and installing same, including a foundation for installation on a seabed below a body of water and a tower connected to and extending upwards from the foundation and being capable of supporting at least an equipment unit. The foundation includes a bottom slab and a wall extending upwards from the bottom slab, thereby defining a first cavity for holding ballast and for providing buoyancy during tow-out and installation. The foundation further includes a circumferential skirt extending downwards from the bottom slab, thereby defining at least one compartment underneath the foundation.

1 - 19 . (canceled) 
     
     
         20 . A support structure for use in the offshore wind farm industry, comprising:
 a foundation for installation on a seabed below a body of water; and   a tower connected to and extending upwards from the foundation and being capable of supporting at least an equipment unit,   wherein the foundation further comprises: a bottom slab element and a wall extending upwards from the bottom slab element, thereby defining a first cavity wherein the foundation comprises a circumferential skirt extending downwards from the bottom slab, thereby defining at least one compartment underneath the foundation.   
     
     
         21 . The support structure of  claim 20 , wherein the tower is connected to the foundation via a lower part of the tower being attached to the bottom slab element. 
     
     
         22 . The support structure of  claim 20 , wherein the tower is connected to the foundation via fixing elements connected to at least an upper wall portion. 
     
     
         23 . The support structure of  claim 20 , wherein the at least one compartment is subdivided into compartments by means of skirts extending downwards from the bottom slab and preferably extending radially from a center portion of the bottom slab to respective areas of the circumferential skirt. 
     
     
         24 . The support structure of claim wherein the foundation comprises a roof structure, extending between an upper wall portion and the tower, thereby enclosing the first cavity. 
     
     
         25 . The support structure of  claim 24 , wherein the roof structure comprises an outer shell and an inner shell defining at least one second cavity there between, said inner shell facing the first cavity. 
     
     
         26 . The support structure of  claim 25 , wherein the second cavity is filled with a material such as concrete. 
     
     
         27 . The support structure of  claim 24 , wherein the roof structure is formed by concrete cast in conventional formwork, or by single shell metal plates. 
     
     
         28 . The support structure of  claim 20 , wherein the bottom slab and the wall comprise an outer shell and an inner shell defining at least one second cavity there between, said inner shell facing the first cavity. 
     
     
         29 . The support structure of  claim 28 , wherein the upper wall is formed by slipform casting or by single shell metal plates. 
     
     
         30 . The support structure of  claim 24 , further comprising a buoyant stabilizing device releasably and slidably connected to the foundation, whereby the stability of the structure is maintained during installation when the roof structure is moved from a position above the water to a fully submerged state. 
     
     
         31 . The support structure of  claim 30 , wherein the buoyant stabilizing device comprises a recessed portion having upper and lower end stops for cooperation with a flange on the foundation, whereby the buoyant stabilizing device slidable movement is restricted by said upper and lower end stops. 
     
     
         32 . The support structure of  claim 30 , wherein the buoyant stabilizing device comprises at least one inner cavity for selective addition and extraction of a ballasting fluid, such as water. 
     
     
         33 . A method of manufacturing the support structure of  claim 20 , comprising the providing of a bottom slab having downwardly extending skirts to an onshore fabrication site, comprising the steps of:
 a) extending a circumferential lower wall from the bottom slab to form a foundation lower part, said lower wall having a vertical extension dimensioned according to the buoyancy requirements for the completed support structure;   b) placing the foundation lower part in a floating position on the body of water;   c) extending an upper wall portion; and   d) connecting the tower to the foundation by attaching a lower part of the tower to the bottom slab and by connecting a part of the tower via fixing elements to at least the upper wall portion of the foundation.   
     
     
         34 . The method of  claim 33 , wherein a roof structure is extended between the upper wall and the tower, thereby enclosing the first cavity. 
     
     
         35 . A method of installing a support structure for use in the offshore wind farm industry, comprising a foundation for installation on a seabed below a body of water and a tower connected to and extending upwards from the foundation and being capable of supporting at least an equipment unit, comprising the steps of:
 a) towing the structure in a floating state to the installation location while controlling the buoyancy and center of gravity of the support by means of a controlled addition of a ballast material into a cavity defined by structural elements of the support structure, whereby the need for separate buoyancy elements and/or specialized vessels during transport is eliminated or significantly reduced, and   b) transferring the structure from a floating state to an installed state, by filling a ballast material into the cavity until the structure is installed on the seabed, whereby the need for separate buoyancy elements and/or specialized vessels and cranes during installation is eliminated or significantly reduced.   
     
     
         36 . The method of  claim 35 , wherein the support structure is moved into a substantially level state on the seabed by injecting a grouting material into selected compartments confined by skirts below a bottom slab element of the support structure. 
     
     
         37 . A method of installing a support structure for use in the offshore wind farm industry, comprising a foundation for installation on a seabed below a body of water and a tower connected to and extending upwards from the foundation and being capable of supporting at least an equipment unit, comprising the steps of:
 a) towing the structure in a floating state to the installation location while controlling the buoyancy and center of gravity of the support by means of a cavity defined by structural elements of the support structure, whereby the need for separate buoyancy elements and/or specialized vessels during transport is eliminated or significantly reduced,   b) transferring the structure from a floating state to an installed state, by filling a ballast material into the cavity until the structure is installed on the seabed, whereby the need for separate buoyancy elements and/or specialized vessels and cranes during installation is eliminated or significantly reduced; and   c) moving the support structure into a substantially level state on the seabed by injecting a grouting material into selected compartments confined by skirts below a bottom slab element of the support structure.   
     
     
         38 . The method of  claim 35 , wherein the filling in step b comprises the filling, at least partly, of water or a solid material or a combination of both. 
     
     
         39 . The method of  claim 37 , wherein the filling in step b comprises the filling, at least partly, of water or a solid material or a combination of both.