Composite connection for a wind turbine tower structure

1. A tower section for a wind turbine tower structure comprising:

at least two shell segments defining, in an assembled condition, a substantially hollow structure, and including a first connecting means for mutually joining two adjacent shell segments along a joint, wherein

the first connecting means comprise a column of concrete arranged overlapping at least part of the joint between the adjacent shell segments,

the first connecting means further comprising a formwork shaped to define an inner volume to be filled with concrete to form the column of concrete joining the adjacent shell segments,

the formwork comprises a first plate associated with a first shell segment and a second plate associated with a second adjacent shell segment, the first and second plates of the formwork are secured by a bolt fitted in a common hole of both plates, and

the first and second plates are bent and the first plate is attached through one edge thereof to the first respective shell segment and the second plate is attached through one edge thereof to the second respective shell segment, while another edge of the first plate substantially overlaps the corresponding other edge of the second plate.

2. The tower section as claimed in claim 1 , wherein the column of concrete is arranged in the interior of the hollow structure.

3. The tower section as claimed in claim 1 , wherein the column of concrete is arranged outside the hollow structure.

4. The tower section as claimed in claim 1 , wherein the column of concrete is arranged both in the interior of the hollow structure and outside the hollow structure.

5. The tower section as claimed in claim 1 , wherein at least one of the shell segments is provided with shear connectors protruding therefrom and embedded in the column of concrete in the assembled condition.

6. The tower section as claimed in claim 1 , wherein the formwork is integral with at least one of the shell segments.

7. The tower section as claimed in claim 1 , wherein the formwork is removable from at least one of the shell segments.

8. The tower section as claimed in claim 1 , wherein the column of concrete of the first connecting means is made of steel reinforced concrete.

9. The tower section as claimed in claim 1 , wherein it further comprises a second connecting means for mutually joining two adjacent tower sections one above the other.

10. The tower section as claimed in claim 9 , wherein the second connecting means comprise a flange adapted for receiving and joining an adjacent tower section, the flange being arranged, in the assembled condition, adjacent a peripheral edge of the shell segments.

11. The tower section as claimed in claim 10 , wherein the flange is discontinuous.

12. The tower section as claimed in claim 10 , wherein the flange has outwardly protruding portions formed in correspondence to the column of concrete.

13. The tower section as claimed in claim 1 , wherein the shell segments are made of metal.

14. A method for building a tower section for a wind turbine tower structure comprising the steps of:

providing at least two shell segments,

placing the shell segments in an assembled condition such that a substantially hollow structure is defined for forming a column of concrete arranged overlapping at least part of a joint between adjacent shell segments, and

providing a formwork shaped to define an inner volume to be filled with concrete so as to form with the concrete a vertical connecting member joining the adjacent shell segments, wherein

the formwork comprises a first plate associated with a first shell segment and a second plate associated with a second adjacent shell segment, the first and second plates of the formwork are secured by a bolt fitted in a common hole of both plates, and

the first and second plates are bent and the first plate is attached through one edge thereof to the first respective shell segment and the second plate is attached through one edge thereof to the second respective shell segment, while another edge of the first plate substantially overlaps the corresponding other edge of the second plate.

15. The method as claimed in claim 14 , wherein it further comprises the step of mutually joining two adjacent tower sections one above the other.

16. A wind turbine comprising a nacelle having rotatable blades and a vertical tower, said tower comprising at least one tower section, the tower section comprising at least two shell segments defining, in an assembled condition, a substantially hollow structure, and including a first connecting means for mutually joining two adjacent shell segments along a joint, wherein

the first connecting means comprise a column of concrete arranged overlapping at least part of the joint between the adjacent shell segments,

the first connecting means further comprising a formwork shaped to define an inner volume to be filled with concrete to form the column of concrete joining the adjacent shell segments,

the formwork comprises a first plate associated with a first shell segment and a second plate associated with a second adjacent shell segment, the first and second plates of the formwork are secured by a bolt fitted in a common hole of both plates, and

the first and second plates are bent and the first plate is attached through one edge thereof to the first respective shell segment and the second plate is attached through one edge thereof to the second respective shell segment, while another edge of the first plate substantially overlaps the corresponding other edge of the second plate.