FOUNDATION FOR AN OFFSHORE STRUCTURE

Abstract

A foundation for an offshore structure, more particularly an offshore wind turbine structure, comprising: at least one tower-like foundation structure with a circumferential foundation wall extending in the longitudinal direction, the foundation wall being delimited at the lower end by a lower-end end face, the foundation wall being formed from a mineral construction material; and at least one binding element, which is formed from a metal material and is arranged on the lower-end end face, the length of the binding element from the lower-end end face to a lower end of the binding element being at least 0.5 m.

Claims

1-15. (canceled)

16. A foundation, comprising: at least one tower-shaped foundation structure with a circumferential foundation wall extending in a longitudinal direction, the foundation wall being bounded on an underside by an underside end face and the foundation wall formed of a mineral building material; at least one binding element formed of a metallic material and arranged on the underside end face; wherein a length of the binding element from the underside end face to a lower end of the binding element is at least 0.5 m; and wherein the binding element comprises a longitudinally extending circumferential tie-in wall and a cross-sectional shape of the binding element corresponds to a cross-sectional shape of the foundation wall.

17. The foundation according to claim 16, wherein: the length of the binding element from the underside end face to the lower end of the binding element is between 1 m and 9 m.

18. The foundation according to claim 16, wherein: the foundation wall is bounded at a top by a top end face; and a wall thickness of the foundation wall is substantially constant from the top end face to the underside end face.

19. The foundation according to claim 16, wherein: a wall thickness of the foundation wall is at least greater than a wall thickness of the tie-in wall.

20. The foundation according to claim 16, wherein: a wall thickness of the foundation wall is between 150 mm and 400 mm; and a wall thickness of the tie-in wall is between 10 mm and 100 mm.

21. The foundation according to claim 16, wherein: the tie-in wall comprises a free end portion, a bound end portion and a connecting portion connecting the free end portion to the bound end portion; and the bonded end portion is incorporated in the foundation wall.

22. The foundation according to claim 21, wherein: a wall thickness of the connecting portion is constant from the free end portion to the bound end portion.

23. The foundation according to claim 21, wherein: a wall thickness of the free end portion is different from a wall thickness of the connecting portion.

24. The foundation according to claim 23, wherein: the wall thickness of the free end portion tapers from the connecting portion to a lower end of the free end portion.

25. The foundation according to claim 23, wherein: the wall thickness of the free end portion is greater than the wall thickness of the connecting portion.

26. The foundation according to claim 21, wherein: an inner diameter of the connecting portion substantially corresponds to an inner diameter of the tower-shaped foundation structure.

27. The foundation according to claim 21, wherein: an outer diameter of the connecting portion substantially corresponds to an outer diameter of the tower-shaped foundation structure.

28. The foundation according to claim 21, wherein: an inner diameter of the free end portion is substantially constant from the connecting portion to a lower end of the free end portion; and an outer diameter of the free end portion tapers from the connecting portion to the lower end of the free end portion.

29. The foundation according to claim 21, wherein: an outer diameter of the free end portion is substantially constant from the connecting portion to a lower end of the free end portion; and an inner diameter of the free end portion tapers from the connecting portion to the lower end of the free end portion.

30. The foundation according to claim 16, wherein: the mineral building material has a compressive strength of more than 150 N/mm.sup.2.

31. The foundation according to claim 16, wherein: the mineral building material has a water-cement ratio less than 0.25 in a bonding region of the tower-shaped foundation structure in which one end of the binding element is bonded in the tower-shaped foundation structure.

32. The foundation according to claim 16, wherein: the foundation supports at least one offshore device.

33. The foundation according to claim 32, wherein: the at least one offshore device comprises an offshore device to generate electrical energy.

34. The foundation of claim 16, wherein: the foundation is an offshore structure foundation.

35. The foundation of claim 34, wherein: the offshore structure foundation is an offshore wind power structure foundation.

36. A method to produce the foundation according to claim 16, comprising: providing on-shore a formwork, wherein the formwork has an annular gap from a first, upper end towards a second, lower end which remains constant; casting the formwork with a liquid concrete; curing the concrete such that the cured concrete forms the tower-shaped foundation structure; and securing the binding element formed of the metallic material to the cured tower-shaped foundation structure.

37. Use of a binding element formed of a metallic material and having a length of at least 0.5 m arranged on an underside end face of a foundation wall of a tower-shaped foundation structure formed of a mineral building material of a foundation of an offshore structure, wherein the binding element comprises a longitudinally extending circumferential tie-in wall and a cross-sectional shape of the binding element corresponds to a cross-sectional shape of the foundation wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] There are now a multitude of possibilities for designing and further developing the foundation according to the application, the offshore structure according to the application, the use according to the application and the methods according to the application. For this purpose, reference is made on the one hand to the claims subordinate to the independent claims, and on the other hand to the description of embodiments in connection with the drawing. The drawing shows:

[0075] FIG. 1 is a schematic view of an embodiment of an offshore structure according to the present application with an embodiment of a foundation according to the present application;

[0076] FIG. 2 is a schematic sectional view of a further embodiment of a foundation according to the present application;

[0077] FIG. 3 is a schematic sectional view of a further embodiment of a foundation according to the present application;

[0078] FIG. 4 is a schematic sectional view of a further example of a foundation according to the present application;

[0079] FIG. 5 is a schematic sectional view of a further embodiment of a foundation according to the present application; and

[0080] FIG. 6 is a diagram of an embodiment of a method according to the present application.

DETAILED DESCRIPTION

[0081] In the following, the same reference signs are used for the same elements. Here, Z refers to the vertical axis and x and y to horizontal axes. Furthermore, in the present application the expressions “bottom”, “lower” etc. and “top”, “upper” etc. refer in particular to the vertical axis z and in particular to the installation state of the foundation.

[0082] FIG. 1 shows a schematic view of an embodiment example of an offshore structure 102 according to the present application with an embodiment example of a foundation 100 according to the present application.

[0083] As an offshore structure 102, an offshore wind power structure 102 in the form of an offshore wind turbine 102 is exemplarily shown in the present application. The offshore structure 102 and thus the foundation 100 are shown in an installation state. The following embodiments can be transferred in a simple manner to other offshore structures.

[0084] The offshore structure 102 comprises at least one foundation 100 and at least one offshore device 116 (e.g. tower, rotor, generator, etc.). The foundation 100 comprises a tower-shaped foundation structure 104. The tower-shaped foundation structure 104 comprises a circumferential foundation wall 105 extending in the longitudinal direction (i.e. along the longitudinal axis).

[0085] The foundation wall 105 is bounded at the lower end 108 of the tower-shaped foundation structure 104 by a lower end face 106. At the upper end 112 of the tower-shaped foundation structure 104, the foundation wall 105 is bounded by an upper-side end surface 110.

[0086] Preferably, the tower-shaped foundation structure 104 is formed as a hollow structural element 104, preferably with a circular cross-sectional area. In particular, the tower-shaped foundation structure 104 may be formed as a hollow pile 104 having an interior 132.

[0087] As described above, FIG. 1 shows the foundation 100 in an installation state in which a tie-in end 118 of the tower-shaped foundation structure 104 is founded in the subsea soil 130 or subsea subsoil 130 (reference mark 128 denotes the subsea soil surface), i.e. is tied into the subsea soil 130 with a depth 122 or tie-in length 122 (e.g. between 7 m and 20 m). The tower-shaped foundation structure 104 protrudes above the water surface 133. The tower-shaped foundation structure 104 may be connected to a transition piece, for example via a grout connection, which is conventionally known.

[0088] The foundation wall 105 is preferably made of concrete (as has been described previously), in particular cast from concrete.

[0089] As can be seen from FIG. 1, the wall thickness 107 or wall thickness 107 remains constant or unchanged in the longitudinal direction (z) along the entire length of the tower-shaped foundation structure 104. The inner diameter 126 of the tower-shaped foundation structure 104 remains constant over the entire length of the tower-shaped foundation structure 104. Furthermore, the outer diameter 124 of the tower-shaped foundation structure 104 is constant along the entire length of the tower-shaped foundation structure 104.

[0090] In other variations of the application, the wall thickness of the foundation structure may change. For example, the wall thickness may taper from the top end face 110 to the bottom end face, for example by increasing the inner diameter and keeping the outer diameter constant, or by decreasing the outer diameter and keeping the inner diameter constant.

[0091] According to the application, at least one binding element 114 made of a metallic material (preferably steel) with a length 120 (measured from the underside end face 106 to the lower end 134) of at least 0.5 m is arranged on the underside end face 106. The lower end 134 means in particular the point of the foundation 100, in particular of the binding element 114, which is bound deepest (in vertical direction z) in the underwater bottom in the installation state of the foundation structure.

[0092] The binding element 114 made of metal, in particular steel, supports the installation process and in particular the displacement of soil material during the installation process.

[0093] In particular, due to the metal design, the wall thickness 152 of a tie-in wall 138 of the tie-in element 114 may be less (e.g. less than 90%, preferably less than 70%, more preferably less than 50% (and more than 10%) of the wall thickness 107 of the foundation wall 105) than the wall thickness 107 of the foundation wall 105.

[0094] FIGS. 2 to 5 show schematic (sectional) views of various embodiments of foundations 200 to 500 according to the present application, in particular with other forms of embedment elements 214 to 514. In order to avoid repetition, essentially only the differences from the preceding embodiment example are described below and otherwise reference is made to the comments on FIG. 1.

[0095] A circumferential binding wall 238 of a metallic binding element 214 can preferably be divided into a (single) bound end portion 244, a free end portion 240 and a connecting portion 242 connecting the bound end portion 244 and the free end portion 240. Preferably, the binding wall 238 is integrally formed.

[0096] As can be seen from FIG. 2, the bound end section 244 is bound, in particular firmly anchored, in the mineral material, in particular the concrete, in a binding region 248 at the lower end 208 of the foundation wall 205. Preferably, a face hole and a dowel anchorage may be used to anchor the bound end portion into the foundation wall.

[0097] Preferably, the mineral building material used in the embedment region 248 of the tower-shaped foundation structure 204, in which the embedded end portion 244 is presently embedded in the tower-shaped foundation structure 204, may be a mineral building material having a compressive strength of greater than 150 N/mm.sup.2 and a w/c ratio of at least less than 0.25.

[0098] In other words, in the area 248 where the incorporated end section 244 extends in the foundation wall 204, in particular an ultra high performance concrete (UHFB; also referred to as Ultra High Performance Concrete) can be used as a mineral building material, while in the remaining section 249 a mineral building material with a lower strength can be used. This can provide sufficient strength, particularly in the tie-in area 248 or connection area between the foundation wall 208 and the tie-in element 214.

[0099] The connecting section 242 adjoining the bound-in end section 244 has, in particular, a wall thickness 252 which is constant in the longitudinal direction (z). The wall thickness 252 is at least less than the wall thickness 207 of the foundation wall 205. The length of the connecting section 242 in the longitudinal direction (z) from the underside end face 206 to the beginning of the free end section 240 may be between 0.2 m and 5.8 m.

[0100] In the preferred embodiment shown, an inner diameter 256 of the connection section 242 substantially corresponds to an inner diameter 226 of the tower-shaped foundation structure 204 (in the region of the underside end face 210). In particular, this means that, as shown in FIG. 2, the respective inner sides of the walls 205, 238 are substantially in line. The outer diameter 260 of the connecting section 242 is smaller than the outer diameter 224 of the foundation wall 205.

[0101] The free end portion 240 has a wall thickness 254 which is modified with respect to the wind force 252, in the present preferred embodiment example a continuously reducing wall thickness 254. As can be seen from FIG. 2, the free end portion 240 has a triangular cross-sectional area in the x-z sectional view. In other words, the free end portion 240 may in particular form a pointed lower end 234 of the binding element 214.

[0102] An inner diameter 258 of the free end portion 240 remains substantially the same or constant from the connecting portion 242 to the lower end 234 of the free end portion 240 in the illustrated preferred embodiment. In particular, an outer diameter 262 of the free end portion 240 (between the end of the connecting portion 242 and the lower end 234 of the free end portion 240) tapers steadily.

[0103] Tests have shown that this embodiment supports the displacement of soil material particularly well and thus makes the installation process particularly easy. In particular, the risk of grafting is reduced, especially when the diameter of the tower-shaped foundation structure is small.

[0104] The embodiment example according to FIG. 3 differs from the embodiment example according to FIG. 2 in particular in that an outer diameter 360 of the connecting section 342 substantially corresponds to an outer diameter 324 of the tower-shaped foundation structure 305 (in the region of the underside end face 310).

[0105] This means in particular that, as shown in FIG. 3, the respective outer sides of the walls 305, 338 are essentially in line. The inner diameter 356 of the connecting section 342 is smaller than the outer diameter 326 of the foundation wall 305.

[0106] The embodiment example according to FIG. 4 differs from the embodiment example according to FIG. 3 in particular in that an outer diameter 462 of the free end portion 440 in the embodiment example shown remains substantially the same or constant from the connecting portion 442 to the lower end 434 of the free end portion 440. In particular, an inner diameter 458 of the free end portion 440 (between the end of the connecting portion 442 and the lower end 434 of the free end portion 440) tapers steadily.

[0107] FIG. 5 differs from the embodiments according to FIGS. 2 to 4 in particular in that a wall thickness 570 (at least immediately adjacent to the connecting portion 542) of the free end portion 540 is greater than the wall thickness 552 of the connecting portion 542. Preferably, the wall thickness 570 of the free end portion 540 may substantially correspond to the wall thickness 507 of the foundation wall 505.

[0108] In particular, the free end portion 540 may be divided into two sub-portions 540.1, 540.2. A first sub-section 540.1 (directly) adjoins the connecting section 542 and in particular has a constant or uniform wall thickness 570, which in particular is greater than the wall thickness 552 of the connecting section 542.

[0109] The second subsection 540.2 (directly) adjoins the first subsection 540.2 and in particular has a (continuously) reducing wall thickness 572. The second subsection 540.2 has in particular the lower end 534. In the x-z sectional view, the second subsection 540.2 has in particular a triangular cross-sectional area.

[0110] As can also be seen from FIG. 5, the inner diameter 526 of the foundation wall 505 preferably corresponds to the inner diameter of the connecting section 542 and in particular to the inner diameter 558 of the free end section 540.

[0111] Furthermore, it can be seen that preferably the outer diameter 560 of the connecting section 542 (with constant wall thickness of the connecting section 542) is smaller than the outer diameter 524 of the foundation wall 505.

[0112] The outer diameter 562.1 of the first sub-section 540.1 is at least larger than the outer diameter 560 of the connecting section 542 and may preferably be substantially equal to the outer diameter 524 of the foundation wall 505. The outer diameter 562.2 of the second sub-section 540.2 preferably reduces steadily.

[0113] Tests have shown that the special design of the binding element 514 according to the embodiment example in FIG. 5 can significantly reduce the sheath friction in the area of the foundation wall 505 and thereby significantly facilitate the installation process.

[0114] FIG. 6 shows a diagram of an embodiment example of a method according to the present application for producing a foundation, in particular a foundation according to one of the embodiment examples according to FIGS. 1 to 5.

[0115] In a step 601, a formwork is provided on-shore, wherein an annular gap in the formwork from a first end of the formwork to a second end of the formwork remains the same or is constant. The annular gap is radially circumferential and extends in the axial direction or in the longitudinal direction over the entire formwork.

[0116] In a step 602, the formwork is poured with a liquid concrete.

[0117] Then, in step 603, the liquid concrete is cured in such a way that the cured concrete forms a tower-shaped foundation structure.

[0118] For example, the tower-shaped foundation structures are cast from concrete using slipform and jumpform methods and are dried in an upright position.

[0119] In step 604, a tie-in element formed of a metallic material is attached to the underside face of the cured tower-shaped foundation structure. In a variant of the application, an insertion of a bound end portion of a binding element formed of a metallic material into the annular gap at the lower end may take place, which may in particular comprise the lower side end face.

[0120] Optionally, in step 605, shipping of the formed tower-shaped foundation structure to an offshore installation location may be performed. In particular, after curing, a formed tower-shaped foundation structure may be rotated once by 180° and loaded onto a vessel 26.

[0121] In step 606, the tower-shaped foundation structure may optionally be rammed or vibrated into the seabed at the installation location.

[0122] In particular, tower-shaped foundation structures may be shipped upright on a vessel to an installation site and founded there using a suitable foundation tool. The tower-shaped foundation structures can already be stored on the ship in such a way that the lower face is at the bottom and the upper face is at the top, so that during foundation the lower face is placed on the underwater bottom and the tower-shaped foundation structure is rammed or vibrated into the underwater bottom by means of the foundation tool.