FOUNDATION FOR A WIND TURBINE WITH FIBER REINFORCED CONCRETE

Abstract

A foundation for a wind turbine tower includes a base slab, a pedestal provided on the base slab, the pedestal including attachment means for attaching the wind turbine tower; and a plurality of radial walls extending from the pedestal towards an outer edge of the base slab, wherein at least one of the base slab, the pedestal and at least one of the plurality of radial walls is made of or includes fiber reinforced concrete.

Claims

1. A foundation for a wind turbine tower, the foundation comprising: a base slab; a pedestal provided on the base slab, the pedestal comprising an attachment means for attaching the wind turbine tower; and a plurality of radial walls extending from the pedestal towards an outer edge of the base slab; wherein at least one of the base slab, the pedestal and at least one radial wall is made of or comprises fiber reinforced concrete.

2. The foundation according to claim 1, wherein at least one of the base slab, the pedestal and at least one radial wall is at least partially free of rebars.

3. The foundation according to claim 1, wherein the plurality of radial walls have a prismatic-triangular or prismatic-trapezoidal shape.

4. The foundation according to claim 1, wherein the base slab has a circular or polygonal shape.

5. The foundation according to claim 1, wherein the fiber reinforced concrete comprises steel microfibers.

6. The foundation according to claim 1, wherein the fiber reinforced concrete comprises polymeric microfibers.

7. The foundation according to claim 6, wherein the polymeric microfibers are polyvinylalcohol microfibers.

8. The foundation according to claim 1, wherein the fiber reinforced concrete comprises crushed recycled wind turbine blades.

9. The foundation according to claim 1, wherein the fiber reinforced concrete comprises synthetic microfibers and/or glass fibers.

10. The foundation according to claim 9, wherein the synthetic microfibers are extruded microfibers.

11. The foundation according to claim 1, wherein the fiber reinforced concrete comprises fibers and/or microfibers having a density of at least 4 kg/m.sup.3.

12. A method for constructing a foundation for a wind turbine tower, the method comprising: providing foundation comprising a base slab, a pedestal provided on the base slab, the pedestal comprising an attachment means for attaching the wind turbine tower, and a plurality of radial walls extending from the pedestal towards an outer edge of the base slab; wherein at least one of the base slab, the pedestal and at least one radial wall is made of or comprises fiber reinforced concrete.

13. The method according to claim 12, wherein the method further comprises: admixing concrete and fibers to obtain fiber reinforced concrete; pouring the fiber reinforced concrete in a framework defining a shape and dimensions of at least one of the slab, the pedestal and at least one radial wall forming the foundation; and curing the fiber reinforced concrete.

14. The method according to claim 12, wherein the fiber reinforced concrete is obtained by admixing fibers and concrete at a workshop, during transportation or at a construction site of the foundation.

15. The method according to claim 12, wherein at least one of the base slab, the pedestal and at least one radial wall is obtained by additive manufacturing of fiber reinforced concrete.

Description

BRIEF DESCRIPTION

[0046] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0047] FIG. 1 shows a perspective view of a foundation of a wind turbine according to a first aspect of the invention;

[0048] FIG. 2 shows an enlarged view of a fiber reinforced concrete piece;

[0049] FIG. 3 shows a diagram to illustrate a method according a second aspect of the present invention; and

[0050] FIG. 4 shows a rebars mesh of a foundation of a wind turbine according to the state of the art.

DETAILED DESCRIPTION

[0051] The illustration in the drawing is schematic. It is noted that in different figures, similar or identical elements or features are provided with the same reference signs or with reference signs, which are different from the corresponding reference signs only within the first digit. In order to avoid unnecessary repetitions elements or features which have already been elucidated with respect to a previously described embodiment are not elucidated again at a later position of the description.

[0052] Further, spatially relative terms, such as “front” and “back”, “above” and “below”, “left” and “right”, et cetera are used to describe an element's relationship to another element(s) as illustrated in the figures. Thus, the spatially relative terms may apply to orientations in use which differ from the orientation depicted in the figures. Obviously all such spatially relative terms refer to the orientation shown in the figures only for ease of description and are not necessarily limiting as an apparatus according to an embodiment of the invention can assume orientations different than those illustrated in the figures when in use.

[0053] FIG. 1 shows a perspective view of a foundation 10 having a circular shape.

[0054] The foundation 10 comprises a base slab 11, on which a pedestal 12 is placed. The pedestal 12 comprises attachment means, here not shown, for attaching or anchoring a wind turbine tower to the foundation 10. The pedestal 12 is placed in the middle of the base slab 11.

[0055] A plurality of radial walls 13 extends from the pedestal 12 towards the edge 111 of the base slab 11. In the embodiment according to FIG. 1, the radial walls 13 do not reach the edge 111. It may however be the case, that the radial walls 13 reach the edge 111.

[0056] The radial walls 13 have a prismatic-triangular shape. It may however also be the case, that the radial walls 13 have a prismatic-trapezoidal shape or that they have another shape. The thickness t of the radial walls is constant in the embodiment according to FIG. 1, although it may vary along the length of the radial wall 13. For example, it may be possible that the radial walls 13 are thicker at the joint with the pedestal 12 and thinner at the slab edge 111.

[0057] Every second radial wall 13 has a void space 131 a void space between the radial wall 13 self and both the pedestal 12 and the base slab 11.

[0058] In the embodiment according to FIG. 1, the foundation 10 is monolithic, meaning that it has been fabricated in only one production run, and it is completely made of fiber reinforced concrete, thus allowing complex forms, such as the radial walls 13 with the void 131, without the need of designing, fabricating and placing a complex rebars mesh, such as the one shown in FIG. 4. In other words, all of the elements of the foundation 10 according to FIG. 1 have no rebars.

[0059] It might however also be the case that more than one concreting phase (production run) is implemented. For example, in a first concreting phase the slab 11 is produced and in a second concreting phase the radial walls 13 and the pedestal 12 are produced.

[0060] FIG. 2 shows an enlarged view of a fiber reinforced concrete piece 20 belonging to the foundation 10 according to FIG. 1. In the fiber reinforced concrete piece 20 there is a multitube of (micro)fibers 21, which are admixed to the concrete in order to give it resistance and strength. The fibers 21 can be of different kinds. For example, they can be steel microfibers, polymeric microfibers or synthetic microfibers and/or glass microfibers. They can be extruded microfibers.

[0061] The fibers 21 can all have the same orientation. However, it is more advantageous for the fibers 21 to have different orientation for guaranteeing a higher resistance and load capacity to the concrete piece 20.

[0062] In the fiber reinforced concrete piece 20 there are also pieces of crushed turbine blade 22, which are recycled after the turbine blades are no longer fit for being used in the wind turbine.

[0063] FIG. 3 shows a diagram to illustrate a method according a second aspect of embodiments of the present invention.

[0064] In a first step S30, the fibers 21 and concrete are admixed to obtain a fiber reinforced concrete. The admixing can happen at the construction site of the foundation 10 or in a production workshop before transporting the concrete to the construction site of the foundation 10. It might however also be the case, the fibers 21 and the concrete are admixed during transportation to the construction or in a workshop prior to transportation to the construction site.

[0065] In a second step S31, the fiber reinforced concrete obtained in step S30 is poured in a cage defining the shape and dimensions of the foundation 10. Alternatively, in step S31 the fiber reinforced concrete obtained in step S30 is used by a 3D-printer for 3D-printing of the foundation 10.

[0066] In a third an final step S32, the poured or printed fiber reinforced concrete is cured to obtain the foundation 10.

[0067] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0068] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.