WIND TOWER CONNECTION SYSTEM

Abstract

The invention introduces a connection system for connecting a shaft of a wind tower to a support surface, by means of a shaft, a foundation cage and a plurality of pairs of tendons wherein each tendon has a lower anchoring adapted for the placement thereof inside the foundation, an upper anchoring, at least one strand with a first end and a second end, the strand extending from the upper anchoring to the lower anchoring, a pair of sleeves for each strand, a sleeve fixed to the upper anchoring and a sleeve fixed to the lower anchoring, each sleeve housing a segment of the strand. Additionally, the system introduces a method for connecting a shaft of a wind tower to a support surface.

Claims

1. A connection system for connecting a shaft of a wind tower to a support surface comprising a foundation , said system comprising: a shaft comprising: a post with a first face (A) and a second face (B), and a fixing end (C), the post being configured to be placed vertically on the support surface, a plurality of pairs of bolts distributed such that each bolt of each pair of bolts is fixed on either the first face (A) or second face (B) of the post, a flange located in the fixing end (C) of the post and adapted for being fixed on the support surface, a plurality of pairs of tendons, each tendon comprising: a lower anchoring adapted for the placement thereof inside the foundation, an upper anchoring, at least one strand with a first end (D) and a second end (D′), the strand extending from the upper anchoring to the lower anchoring, a pair of sleeves for each strand, a sleeve fixed to the upper anchoring and a sleeve fixed to the lower anchoring, each sleeve housing a segment of the strand, and a foundation cage covering at least a part of each strand and of the upper anchoring, embedding the pairs of bolts.

2. The system according to claim 1, wherein at least one upper anchoring or lower anchoring comprises: at least one distribution plate comprising a perforation for each strand, the sleeve being housed in said perforation, at least one wedge plate comprising at least one hole housing the first end or second end (D, D′) of the strand, the wedge plate being located on the at least one distribution plate such that each perforation coincides with each hole, at least one wedge housed in the hole which allows fixing the end (D, D′) of the strand to the wedge plate, at least one retention plate located on the at least one wedge plate, which has projecting therefrom the end (D, D′) of the strand and which retains the at least one wedge, and at least one sealing gasket which allows fixing the at least one retention plate to the at least one wedge plate.

3. The system according to claim 2, wherein at least one upper anchoring or lower anchoring further comprises: a cap covering the end (D, D′) of the strand projecting from the at least one retention plate.

4. The system according to claim 1 further comprising a mortar bed adapted for being located between the fixing end (C) of the flange and the support surface.

5. The system according to claim 1, wherein the tendon further comprises a helix partially surrounding a strand.

6. The system according to claim 5, wherein the helix is fixed to the at least one distribution plate on a face opposite the face where the at least one wedge plate is fixed.

7. The system according to claim 1, wherein the post is a metal post.

8. The system according to claim 1, wherein the bolts are metal bolts.

9. The system according to claim 1, wherein the bolts and the flange are welded to the post.

10. The system according to claim 1, wherein each strand is formed by a plurality of wires.

11. A method for connecting a shaft of a wind tower to a support surface, comprising: providing an excavation on the support surface adapted for making a foundation, providing a system according to claim 1, fixing the lower anchoring of the at least one tendon into the excavation, pouring concrete into the excavation, the foundation being obtained, locating the shaft on the foundation, locating the upper anchoring together with the end (D, D′) of the strand in their final position of connection, making the foundation cage, and stressing the at least one tendon.

12. A method for connecting a shaft of a wind tower to a support surface according to claim 11, wherein after the step of locating the shaft on the foundation the following step is performed: making a mortar bed between the flange and the support surface.

13. The method for connecting a shaft of a wind tower to a support surface according to claim 11, wherein the step of locating the upper anchoring together with the end (D, D′) of the strand comprises: placing the tendon and the at least one distribution plate, and placing the at least one wedge plate and the at least one wedge.

14. The method for connecting a shaft of a wind tower to a support surface according to claim 11, wherein the foundation comprises a rebar, and the at least one upper anchoring or lower anchoring is fixed to the rebar of the foundation.

15. The system according to claim 1, wherein each strand is made of steel.

Description

DESCRIPTION OF THE DRAWINGS

[0092] The foregoing and other features and advantages of the invention will be more clearly understood based on the following detailed description of a preferred embodiment given only by way of illustrative and non-limiting example in reference to the attached drawings.

[0093] FIG. 1 shows a section in perspective view of a shaft of a wind tower connected to a support surface by means of a connection system according to one embodiment.

[0094] FIG. 2 shows a longitudinal section of a pair of tendons of a connection system according to the preceding figure.

[0095] FIG. 3 shows a section of an upper anchoring or a lower anchoring according to one embodiment.

[0096] FIG. 4 shows a plan view of a connection system according to one embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0097] FIG. 1 shows a connection system (15) for connecting a shaft (3) of a wind tower to a support surface (1) according to a preferred embodiment.

[0098] Said support surface (1) comprises a foundation (2) made of concrete and a metal rebar (not shown in the drawing).

[0099] A mortar bed (14) is arranged on the foundation (2) and a flange (6) belonging to the shaft (3) of the wind tower is arranged thereon.

[0100] The flange (6) is located in the fixing end (C) of the post (4), both the post (4) and the flange (6) being metal post and flange.

[0101] The post (4) defines a first face (A) and a second face (B), in this case the second face (B) being the inner face of the post (4) and the first face (A) the outer face of said post (4) as seen in FIG. 1.

[0102] The shaft (3) also comprises a series of pairs of bolts (5) distributed in the lower area of the post (4). These bolts (5) are metal bolts and are distributed in pairs on both faces (A, B) in a segment of the post (4) according to the longitudinal direction thereof. Each of the pairs of bolts (5) is in turn arranged on a plane transverse to said longitudinal direction of the post (4), thereby being located along the entire perimeter of the post (4), in this case circular.

[0103] Each of the bolts (5) is welded to the post (4), as well as the flange (6).

[0104] As seen in FIG. 1, the connection system (15) has about a total of 60 tendons (7), uniformly distributed throughout the section of the post (4).

[0105] In this preferred example, the tendons (7) are completely embedded in concrete, either in the foundation (2) like the case of the lower anchorings (8) and part of the strands (9) or in the foundation cage (13) like the case of another part of the strands (9) and of part of the upper anchorings (8′).

[0106] In this case, the upper anchorings (8′) are not completely embedded in the concrete.

[0107] As seen in FIG. 1, both the lower anchorings (8) and the upper anchorings (8′) have associated therewith a helix (12) surrounding the strand (9) in a segment.

[0108] FIG. 2 shows a pair of tendons (7) which are already mounted such that the connection between the shaft (3) and the support surface (1) is established.

[0109] In this case, the two lower anchorings (8) are embedded in the concrete of the foundation (2), and anchored to the rebar thereof (not shown in the drawings).

[0110] The strands (9) are in turn embedded in the concrete of the foundation (2) as well as in the concrete of the foundation cage (13).

[0111] At the other end of each tendon (7), the upper anchorings (8′) are fixed to the rebar of the foundation cage (not shown in the drawings), and partially covered by the concrete thereof. The segment of said upper anchorings (8′) outside the foundation cage (13) is covered by a seal (11) protecting the end of the tendon (7) from external aggressions.

[0112] In this case, the strands (9) are made of steel and are non-adherent strands, so they are sheathed and greased throughout their entire length. They are furthermore surrounded by helixes (12) at their ends.

[0113] FIG. 3 shows a detail of one of the upper and lower anchorings (8, 8′), comprising a distribution plate (8.1, 8′.1) and a wedge plate (8.2, 8′.2) as well as wedges (8.3, 8′.3).

[0114] Each of the strands (9) is sheathed and greased or waxed in the sleeves (10, 10′) protecting same. Said sleeves (10, 10′) are in turn surrounded by a helix (12) fixed on the distribution plate (8.1, 8′.1).

[0115] Both the distribution plate (8.1, 8′.1) and the wedge plate (8.2, 8′.2) located thereon have holes (8.1.1, 8′.1.1) axially coinciding in the mounting with the strands (9) going therethrough.

[0116] Each of the strands (9) is fixed to the wedge plate (8.2, 8′.2) through metal wedges (8.3, 8′.3) maintaining the position of the ends (D, D′) of said strands (9).

[0117] A retention plate (8.5, 8′.5) preventing the wedges (8.3, 8′.3) from changing their position is arranged on the wedge plate (8.2, 8′.2) and protecting the segment protruding from the ends (D, D′) of said strands (9).

[0118] A sealing gasket (8.4, 8′.4), allowing said retention plate (8.5, 8′.5) to maintain its position is arranged between the retention plate (8.5, 8′.5) and the wedge plate (8.2, 8′.2).

[0119] The excess segment of each strand (9) projecting from the retention plate (8.5, 8′.5) is covered by a plastic cap (8.6, 8′.6) protecting it.

[0120] This segment is covered once the tendons (7) have been stressed through each of their strands (9) and the excess has been cut.

[0121] FIG. 4 shows the plan view of a lower or upper anchoring (8, 8′) illustrating therein a distribution plate (8.1, 8′.1) and a tendon (7) arranged thereon made up of 4 strands (9), each strand (9) being made up of 7 wires (9.1).

[0122] These strands (9) are sheathed in their sleeves (10, 10′), and all of them are housed inside the helix (12).