Hybrid monopile and wind turbine

Abstract

The invention relates to a hybrid monopile (1, 14, 20, 28) for an offshore wind turbine, having a tubular pile (2, 15, 21, 29) which acts as a foundation, is produced from steel and can be introduced into the ground. The hybrid monopile (1, 14, 20) has a tubular concrete shaft (6, 16, 24, 30) having a lower section (7, 17, 27, 31) and an upper section (8, 25, 33), the concrete shaft (6, 16, 24, 30) being assembled from precast concrete parts which are braced together, and the lower section (7, 17, 27, 31) of the concrete shaft (6, 16, 24, 30) being fitted into or over an upper section (4, 23) of the pile (2, 15, 21, 29). The invention also relates to an offshore wind turbine having a hybrid monopile (1, 14, 20) of this kind.

Description

[0001] Hybrid monopile and wind turbine

[0002] The invention relates to a hybrid monopile, in particular for an offshore wind turbine, with a tubular pile made of steel serving as a foundation, which can be inserted into a subsoil.

[0003] Different types of foundations are used for offshore wind turbines. In addition to monopiles, the foundation can be designed as a tripod, jacket, bucket, triple pile, or a foundation anchored to the seabed. A connecting piece is typically placed on top of the foundation, supporting the tower and a turbine.

[0004] A monopile has the advantage of being less complex in technology than other offshore foundations. Monopiles have therefore become the preferred foundation type in waters with rock-free bottom structures up to approximately 45 m deep. The steel pile is manufactured from steel sheets onshore and transported by ship to the planned location. There, the pile is driven into the seabed using a ramming method.

[0005] In view of the currently planned expansion of offshore wind turbines, there is therefore a need for a hybrid monopile that can be manufactured and assembled economically and reduces the risk of bottlenecks in the supply chain.

[0006] The invention is therefore based on the object of providing a monopile which can be manufactured and assembled simply and economically.

[0007] To solve this problem, a hybrid monopile having the features of claim 1 is provided.

[0008] A hybrid monopile for an offshore wind turbine comprises a tubular steel pile serving as a foundation, which can be driven into the ground, particularly by ramming. The hybrid monopile has a tubular concrete shaft with a lower section and an upper section, with the concrete shaft composed of precast concrete elements braced together. The lower section of the concrete shaft is inserted into or over an upper section of the pile.

[0009] The hybrid monopile according to the invention is characterized in that it has a tubular concrete shaft with a lower section and an upper section, which is composed of prefabricated concrete elements or concrete tubes braced together, wherein the lower section of the concrete shaft is inserted into an upper section of the pile or over the upper section of the pile.

[0010] The invention is based on the discovery that a particularly cost-effective production of a hybrid monopile is possible by assembling it from two components that are comparatively simple to construct and manufacture. The lower part of the hybrid monopile is formed by the pile, which consists of a steel tube. The concrete shaft mounted on top can also be manufactured using established methods. After the pile has been driven into the seabed, for example by ramming, the concrete shaft is mounted on the pile, thus forming the hybrid monopile. The concrete shaft is either inserted into the upper section of the pile, or alternatively, the concrete shaft can be inserted over the upper section of the pile, so that the concrete shaft is located outside the pile.In both variants, the upper section of the pile and the lower section of the concrete shaft are shaped so that they can be inserted into or on top of each other.

[0011] Preferably, the upper section of the pile and the lower section of the concrete shaft are shaped in the same way in the sense that they abut one another at least in sections, preferably over an area extending completely around a central longitudinal axis of the monopile, in particular they abut one another in a form-fitting and / or force-fitting manner.

[0012] Terms such as "top", "bottom", "radially inward", "radially outward" and the like are to be interpreted with reference to a monopile which extends in a conventional manner over an axial length around a central longitudinal axis which is oriented in a vertical direction. A direction along or parallel to the central longitudinal axis is also referred to as the axial direction in the context of this disclosure. Accordingly, a direction perpendicular to the central longitudinal axis is also referred to as the radial direction. According to advantageous embodiments, the pile is designed to be sunk sectionally into the seabed such that the upper section of the pile is at least partially arranged above the seabed. The concrete shaft is preferably designed to extend from the upper section of the pile above a water surface.

[0013] In a preferred embodiment, the lower section of the concrete shaft is conical and inserted into the upper section of the pile, in particular such that the concrete shaft is inserted concentrically into the pile and aligned along the central longitudinal axis.

[0014] Preferably, the lower section of the concrete shaft is conical, and the upper section of the pile has the same taper as the lower section of the concrete shaft. The two conical sections of the pile and the concrete shaft have essentially the same taper, allowing the concrete shaft and the pile to be inserted into each other.

[0015] In one possible embodiment, in which the concrete shaft is located on the inside, in particular radially inward, and the upper section of the pile is located on the outside, in particular radially outward, the lower section of the concrete shaft tapers and thus forms a conical seat. The opening in the upper section of the pile widens upwards, in particular funnel-shaped. The conical connection gives the monopile the necessary stability. The connection, which is formed by the conical seat of the concrete shaft, which is inserted into the funnel-shaped widening of the pile and preferably rests against it over a full circumference around the central longitudinal axis, advantageously centers the acting loads in the direction of the central longitudinal axis of the monopile.

[0016] A variant of the invention provides that the concrete shaft is double-conical in a lower region and has a conical section with a conicity opposite to that of the lower section of the concrete shaft. In an exemplary embodiment of the invention, the lower region of the concrete shaft is thus particularly double-conical and has two conical sections with opposite conicities. The lower of the two conical sections, when assembled, forms the lower section of the concrete shaft, which is inserted into the upper section of the pile. The lower section of the concrete shaft and the upper section of the pile have the same conicity.

[0017] In advantageous embodiments of the invention, the upper section of the pile is designed to be opposite to the lower section of the concrete shaft.

[0018] Preferably, the pile and the concrete shaft are interlocked and connected to each other with a positive and / or non-positive fit. Therefore, additional connecting elements between the pile and the concrete shaft are generally not required; however, if necessary for a specific application, additional connecting elements can of course be used.

[0019] It can also be provided that the pile - apart from its upper section - has a constant diameter or tapers conically towards the top.

[0020] In possible designs, the pile has a constant diameter outside its upper section.

[0021] In possible configurations, the lower section of the concrete shaft is cylindrical and inserted over the upper section of the pile. Optionally, the pile tapers upwards outside its upper section, in particular to support an upper section with a substantially cylindrical shape, which can be inserted into the lower section of the concrete shaft.

[0022] Preferably, the precast concrete components of the concrete shaft which are clamped together comprise cylindrical and / or conical ring segments which, when assembled into rings and stacked on top of one another, provide the concrete shaft at least in sections.

[0023] Within the scope of the invention, it is therefore particularly preferred that the concrete shaft be composed of cylindrical and / or conical ring segments that are assembled into rings and, in particular, stacked on top of one another in a dry manner, i.e., without additional bonding agents. Alternatively or additionally, the concrete shaft can be composed of stacked rings, such as concrete tubes. Rings and ring segments can also be used simultaneously. For example, the lower region, which has a larger diameter, can contain ring segments assembled into rings, whereas the upper region, which has a smaller diameter, can be formed from rings.

[0024] According to a preferred variant of the invention, the upper section of the concrete shaft can be conical and taper upwards. Alternatively, the upper section of the concrete shaft can have a conically tapered section and a section of constant diameter arranged thereon.

[0025] A preferred embodiment of the invention provides that the ring segments and / or the rings and / or concrete tubes are braced together by means of tendons. Both the ring segments and the rings can be prefabricated and pre-assembled on land. Accordingly, the entire concrete shaft, consisting of stacked rings, can be pre-assembled and subsequently braced. Strands are preferably used as tendons, which extend either within the rings or ring segments or, alternatively, run inside the tower wall. Thus, in a preferred embodiment, the tower wall is provided by rings or ring segments which are provided with axially extending recesses for the tendons, in particular strands or strand bundles.The prefabricated and tensioned tubular concrete shaft is connected in this pre-assembled state to the pile driven into the seabed, forming the hybrid monopile.

[0026] In an advantageous embodiment, the precast concrete components of the concrete shaft, in particular the ring segments and / or rings and / or concrete tubes, which are clamped together, are axially clamped together by means of the tendons, wherein the tendons are arranged at least over an axial length inside a tower wall of the concrete shaft.

[0027] Preferably, a transition piece is arranged on the upper end of the concrete shaft. The transition piece forms the connection between the hybrid monopile and a structure. The transition piece is designed to support a tower, in particular a tower with a turbine.

[0028] Preferably, the tendons, in particular prestressing strands or prestressing strand bundles, are tensioned between the transition piece, which is arranged at an upper end of the concrete shaft, and a lower end of the concrete shaft. The tendons are preferably anchored to the transition piece.

[0029] In one possible design, the tendons are anchored at the lower end of the concrete shaft. Alternatively, the tendons can be deflected at the lower end of the concrete shaft and braced at the upper end of the concrete shaft. The hybrid monopile can therefore be designed so that tendons bracing the ring segments and / or the rings and / or the concrete tubes are anchored at their upper end to the transition piece and at their lower end to the concrete shaft, or are deflected at the lower end of the concrete shaft and braced at the upper end of the concrete shaft. In the latter design, the transition piece can also be pre-assembled on land as part of the concrete shaft.

[0030] It is particularly preferred that a tower, preferably a tubular steel tower or a concrete tower, be arranged on the transition piece. The tower can have a turbine with a nacelle in which a generator is arranged. The turbine also includes a hub and rotor blades.

[0031] The invention is explained below using exemplary embodiments with reference to the drawings. The drawings are schematic representations and show:

[0032] Fig. 1 shows a first embodiment of a hybrid monopile in a sectional view;

[0033] Fig. 2 is a perspective view of the hybrid monopile shown in Fig. 1;

[0034] Fig. 3 shows a second embodiment of a hybrid monopile in a sectional view;

[0035] Fig. 4 shows a third embodiment of a hybrid monopile in a sectional view;

[0036] Fig. 5 is a perspective view of the monopile shown in Fig. 4; Fig. 6 is a sectional view of a fourth embodiment of a hybrid monopile; and

[0037] Fig. 7 is a perspective view of the monopile shown in Fig. 6.

[0038] The hybrid monopile 1 shown in Figs. 1 and 2 comprises a tubular, steel-made pile 2 serving as a foundation, which is driven into a seabed 3. An upper section 4 of the pile 2 tapers downwards, i.e., the diameter of the pile 2 is larger at its upper, open end than in a lower section 5, which has a constant diameter. In the illustrated embodiment, the lower section 5 is approximately five times as long as the upper section 4. This ratio of the length of the lower section 5 to the length of the upper section 4 is merely an example.

[0039] A tubular concrete shaft 6 is inserted into the pile 2, which is composed of prefabricated concrete elements that are braced together. These are rings 37 or ring segments 36 that are assembled to form rings 37 and stacked on top of one another. After stacking, the rings 37 and / or ring segments 36 are braced together by means of tendons. In the illustrated embodiment, the tendons (not shown) run inside the ring segments 36 or rings 37, which provide the tower walls of the concrete shaft 6. The tendons thus extend over the axial length of the concrete shaft 6 along the central longitudinal axis L, with the tendons being arranged inside the tower wall of the concrete shaft 6.

[0040] The concrete shaft 6 comprises a lower section 7 and an upper section 8. The lower section 7 of the concrete shaft 6 is conical, in particular in the form of a conical seat, and is inserted into the upper section 4 of the pile 2. The lower section 7 of the concrete shaft 6 has the same conicity as the upper section 4 of the pile 2 and tapers downwards. In the assembled state, which is shown in Fig. 1 and 2, the lower section 7 is practically completely inserted into the upper section 4 of the pile 2, so that these sections 4, 7 abut one another, in particular in an area which extends completely around a longitudinal axis L of the concrete shaft 6 or monopile 1. The upper section 8 of the concrete shaft has a conicity that is the opposite of that of the lower section 7, ie it tapers upwards. In the illustrated embodiment, the upper section 8 is approximately five times as long as the lower section 7.This length ratio is also intended only as an example, and other designs are also possible. At the upper end 39 of the concrete shaft 6 is a ring 9 with a constant diameter.

[0041] A transition piece 10 is arranged on the uppermost ring 9, which forms the connection between the hybrid monopile 1 and a steel tube tower 11, which is only indicated in Fig. 1 and 2. A working platform 12 is attached above the transition piece 10 to the steel tube tower 11. The tendons, which can in particular be designed as prestressing strands or prestressing strand bundles, are tensioned between the transition piece 10 arranged on the upper end 39 of the concrete shaft 6 and a lower end 40 of the concrete shaft 6. In the embodiment shown, the tendons are each anchored at the end to the transition piece and at the lower end 40. In an alternative embodiment, the tendons are deflected at the lower end of the concrete shaft 6 and tensioned at the upper end 39 of the concrete shaft 6.

[0042] The hybrid monopile 1 described in this embodiment is designed such that, in the assembled state, approximately one quarter of the length of the concrete shaft 6 protrudes above the sea surface 13.

[0043] Fig. 3 shows a second embodiment of a hybrid monopile 14, which is designed similarly to the hybrid monopile 1 shown in Figs. 1 and 2. Identical components will therefore not be explained again in detail.

[0044] A pile 15 made of steel, unlike in the previous embodiment, has a constant conicity in the sense of a substantially cylindrical configuration. The concrete shaft 16 has a conical lower section 17 that tapers downwards. In this case, therefore, there is not a positive fit over the entire axial length of the lower section 17. Only in the area of ​​the upper opening of the pile 15 does it touch a section 18 of the concrete shaft 16 in an area extending completely around the central longitudinal axis. The diameter of the concrete shaft 16 is at its largest in the area of ​​section 18.

[0045] Unlike in the previous embodiment, in the area of ​​the upper

[0046] Section 18 of the pile 15, ie where the concrete shaft 16 and the pile 15 are inserted into each other, there is an additional ring-segment-shaped reinforcement 19 on the inside of the concrete shaft 16.

[0047] Figs. 4 and 5 show another embodiment of a hybrid monopile 20, with Fig. 4 being a sectional view and Fig. 5 being a perspective view. The monopile 20 comprises a pile 21 driven into the seabed. The lower section 22 of the pile 21 has a constant circular cross-section. An upper section 23 of the pile 21 is conical and widens upwards.

[0048] The monopile 20 further comprises a tubular concrete shaft 24 which is inserted into the upper, conical end of the pile 21. The tubular concrete shaft 24 has an upper section 25 with a constant diameter, i.e. the upper section 25 is cylindrical. Below this is a conical section 26 whose diameter increases from top to bottom. The drawings show that the diameter of the upper section 25 of the tubular concrete shaft 24 is smaller than the diameter of the pile 21. The conical section 26 thus forms a transition between the upper section 25 of the concrete shaft 24 and the pile 21. Below the conical section 26 of the tubular concrete shaft 24 is a lower section 27 which is inserted into the conical upper section 23 of the pile 21. The lower section 27 of the concrete shaft 24 and the upper section 23 of the pile 21 have the same conicity. As best shown in Fig.4, the conicity of the lower section 27 of the concrete shaft 24 is inverse to the conicity of the conical section 26 located above it. In the lower section 27, the diameter increases from bottom to top, while in the conical section 26 it decreases from bottom to top.

[0049] In accordance with the previous embodiment, a transition piece is located at the upper end of the concrete shaft 24. A tubular steel tower 11 with a working platform 12 is arranged on the transition piece.

[0050] 6 and 7 show a further embodiment of a hybrid monopile 28, wherein Fig. 6 is a sectional view and Fig. 7 is a perspective view. The monopile 28 comprises a pile 29 which has a constant circular cross-section. A tubular concrete shaft 30 is inserted over the upper section of the pile 29. In the illustrated embodiment, the tubular concrete shaft 30 has a lower section 31 with a constant diameter. In other words, the lower section 31 of the concrete shaft 30 is cylindrical. This lower section 31 of the concrete shaft 30 is slipped or inserted over the upper section 34 of the pile 29. Above the lower section 31 of the concrete shaft 30 is a conical section 32 of the concrete shaft 30, the diameter of which decreases towards the top. An adjoining uppermost section 33 of the concrete shaft 30 has a constant diameter.At the upper end of the monopile 28 there is a transition piece 10 in accordance with the previously described embodiments.

[0051] List of reference symbols

[0052] 1 hybrid monopile

[0053] 2 posts

[0054] 3 Seabed

[0055] 4 upper section (pile)

[0056] 5 lower section (pile)

[0057] 6 concrete shaft

[0058] 7 lower section (concrete shaft)

[0059] 8 upper section (concrete shaft)

[0060] 9 top ring

[0061] 10 Transition piece

[0062] 11 steel tube tower

[0063] 12 work platforms

[0064] 13 Sea surface

[0065] 14 hybrid monopiles

[0066] 15 post

[0067] 16 concrete shaft

[0068] 17 lower section (concrete shaft)

[0069] 18 Section (Pillar)

[0070] 19 reinforcements

[0071] 20 hybrid monopiles

[0072] 21 Post

[0073] 22 lower section (pile)

[0074] 23 upper section (pile)

[0075] 24 concrete shaft

[0076] 25 upper section (concrete shaft)

[0077] 26 conical section (concrete shaft)

[0078] 27 lower section (concrete shaft)

[0079] 28 hybrid monopiles

[0080] 29 Post

[0081] 30 concrete shaft

[0082] 31 lower section (concrete shaft)

[0083] 32 conical section (concrete shaft)

[0084] 33 uppermost section (concrete shaft) lower section (pile) upper section (pile) ring segment ring

Claims

Patent claims 1. Hybrid monopile (1, 14, 20, 28) for an offshore wind turbine, with a tubular pile (2, 15, 21, 29) made of steel and serving as a foundation, which can be inserted into a subsoil, characterized in that the hybrid monopile (1, 14, 20) has a tubular concrete shaft (6, 16, 24, 30) with a lower section (7, 17, 27, 31) and an upper section (8, 25, 33), wherein the concrete shaft (6, 16, 24, 30) is composed of prefabricated concrete parts braced together, wherein the lower section (7, 17, 27, 31) of the concrete shaft (6, 16, 24, 30) is inserted into or over an upper section (4, 23) of the pile (2, 15, 21 , 29) is plugged in.

2. Hybrid monopile according to claim 1, wherein the lower portion (7, 17, 27) of the concrete shaft (6, 16, 24) is conical and is inserted into the upper portion (4, 23) of the pile.

3. Hybrid monopile according to claim 2, wherein the upper portion (4, 23) of the pile has the same conicity as the lower portion (7, 17, 27) of the concrete shaft (6, 16, 24).

4. Hybrid monopile according to claim 2 or 3, wherein the concrete shaft (6, 16, 24) has in a lower region a conical section with a conicity opposite to the lower section (7, 17, 27) of the concrete shaft (6, 16, 24).

5. Hybrid monopile according to one of the preceding claims, wherein the upper section (4, 23) of the pile (2, 15, 21, 29) is formed opposite to the lower section (7, 17, 27, 31) of the concrete shaft (6, 16, 24, 30).

6. Hybrid monopile according to one of the preceding claims, wherein the pile (2, 15, 21, 29) and the concrete shaft (6, 16, 24, 30) are inserted into one another in a form-fitting and / or force-fitting manner.

7. Hybrid monopile according to one of the preceding claims, wherein the pile (2, 15, 21, 29) has a constant diameter outside its upper section (4, 23).

8. Hybrid monopile according to one of the preceding claims 2 to 7, wherein the lower section (31) of the concrete shaft (6, 16, 24) is cylindrical and is placed over the upper section (4, 23) of the pile (29), wherein optionally the pile (2, 15, 21, 29) tapers conically upwards outside its upper section (4, 23).

9. Hybrid monopile according to one of the preceding claims, wherein the prefabricated concrete components of the concrete shaft (6, 16, 24) which are braced together comprise cylindrical and / or conical ring segments (36) which, when assembled into rings (37) and stacked one on top of the other, provide the concrete shaft (6, 12, 24) at least in sections.

10. Hybrid monopile according to one of the preceding claims, wherein the prefabricated concrete components of the concrete shaft (6, 16, 24, 30) which are braced together comprise rings (37), in particular concrete tubes, which provide the concrete shaft (6, 12, 24, 30) at least in sections.

11. Hybrid monopile according to one of the preceding claims, wherein the upper section (8) of the concrete shaft (6) is conical and tapers upwards or that the concrete shaft (24) has an upwardly tapering conical section (26) and an upper section (25) of constant diameter arranged thereon.

12. Hybrid monopile according to one of the preceding claims, wherein the precast concrete components of the concrete shaft (6, 16, 24, 30), in particular ring segments (36), rings (37) and / or concrete tubes, which are clamped together, are axially clamped together by means of tendons, wherein the tendons are arranged at least over an axial length inwardly in a tower wall of the concrete shaft.

13. Hybrid monopile according to one of the preceding claims, wherein a transition piece (10) is arranged on the upper end of the concrete shaft (6, 16, 24, 30), wherein the tendons, in particular prestressing strands or prestressing strand bundles, are tensioned between a transition piece (10) which is arranged at an upper end of the concrete shaft (6, 16, 24, 30) and a lower end (40) of the concrete shaft (6, 16, 24, 30), wherein the tendons are anchored to the transition piece (10).

14. Hybrid monopile according to claim 13, wherein the tendons are anchored at the lower end (40) of the concrete shaft (6, 16, 24, 30) or wherein the tendons are deflected at the lower end of the concrete shaft (6, 16, 24, 30) and tensioned at the upper end (39) of the concrete shaft (6, 16, 24, 30).

15. Offshore wind energy plant, with a hybrid monopile (1, 14, 20) according to one of the preceding claims with a tower, preferably a steel tube tower (11), arranged on the concrete shaft (6, 16, 24, 30), in particular a transition piece (10), and a turbine arranged on the tower.

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