AU2014317440A1

AU2014317440A1 - Jacket for a wind turbine and method for the production of said jacket

Info

Publication number: AU2014317440A1
Application number: AU2014317440A
Authority: AU
Inventors: Peter Kelemen
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-09-04
Filing date: 2014-09-03
Publication date: 2016-03-17
Also published as: WO2015032495A3; WO2015032495A2; EP3042010B1; DE102013015299B4; DE202013012249U1; EP3042010A2; DE102013015299A1

Abstract

The invention relates to a jacket (1) for a wind turbine, said jacket having at least three legs (2), a length L and a plurality of struts (4), each strut extending between two legs (2) and struts (4) being provided between the legs (2) over at least a large part of the length L which do not cross any other struts (4). The jacket is characterised in that in different regions of the legs (2), there are only two respective struts (4) in contact with a leg (2) and running to only one adjacent leg (2).

Description

WO 2015/032495 - 1 - PCT/EP2014/002387 Jacket for a wind turbine and method for the production of said jacket Description 5 The invention relates to a jacket for a wind turbine which has at least three legs of a length L and multiple struts which each extend between two legs, wherein at least over the majority of the length L struts are arranged between the legs and do not cross 10 any other struts. A so-called jacket is a foundation structure for fastening in particular an offshore wind turbine on the sea bed. They often take the form of four-legged 15 framework-like steel constructions. Jackets with a different number of legs are of course also known. Sleeves which, for example, receive piles driven into the sea bed and thus ensure the anchoring of the jacket to sea bed, are often arranged at the lower ends of the 20 legs. A connecting element is situated at the upper end of the jacket which is usually arranged above the water level in the case of offshore wind turbines. The actual tower of the wind turbine, at the upper end of which the nacelle with the rotor is situated, is positioned 25 on said connecting element. Compared with other foundation structures, jackets have the advantage of ensuring sufficient stability even at relatively great water depths and at the same time of 30 presenting a relatively small surface to oncoming waves and sea currents such as, for example, high and low tides. Struts which are arranged crossing each other are 35 usually situated between the respective legs of the jacket. This results in good stability and very good torsional rigidity of the jacket, which is advantageous 2582577v1 WO 2015/032495 -2- PCT/EP2014/002387 in particular in the case of offshore wind turbines owing to the high loads placed on them by sea currents and/or swells. 5 Jackets are used, for example, in water depths of up to 60 meters and must have correspondingly large dimensions. The gap between two legs of the jacket can here easily exceed 25 meters. A disadvantage is that the production and construction of the jacket are 10 complex and hence expensive. During production, the crossed struts which are arranged between the legs of the jacket are usually delivered as a separate component already in the form of a cross and must be positioned between the respective legs between which 15 they are intended to extend. These struts too can consequently easily reach a length of 20 meters to 30 meters and nevertheless must be manufactured in such a way that all four ends of the two crossed struts can be fastened to the respective legs which are present as a 20 prefabricated component. This means that, despite the enormous dimensions of the struts and the legs of the jacket, very low manufacturing tolerances need to be observed. A deviation of just a few centimeters, for example in the length of one of the two struts, can 25 result in the need to manufacture and insert spacers in a complex fashion or in it being impossible to use the two crossed struts at all. There is furthermore a need for multiple complex 30 contour welds when crossed struts are used because both the legs and the struts are tubular in design. These welds often need to be made unprotected on the construction site (dockyard), which is complex and expensive and almost impossible in particular in the 35 event of bad weather. In addition, the points on the legs at which the individual struts are arranged need 2582577v1 WO 2015/032495 -3- PCT/EP2014/002387 to be reinforced separately. Thus four struts, which all need to be fastened by complicated contour welds at the same region of the leg which needs to be designed specially for this purpose, usually meet in a region of 5 a leg of the jacket. The crossed struts are thus often arranged so densely above one another between the legs that the upper ends of the lower cross and the lower ends of the upper cross meet the respective leg very closely to each other. However, this applies not only 10 for a leg adjacent, for example, to the first leg in a clockwise direction so that often four struts need to be arranged in a very small space in the region in which the struts meet the legs. This too complicates the production and makes the construction of the jacket 15 time-consuming, complicated and expensive. A support structure for offshore platforms for oil and gas exploration and/or production is known from DE 38 19 233 C2 which discloses all the features of the 20 preamble to claim 1, apart from the fact that it is not designed for wind turbines. In contrast, EP 2 067 913 A2 discloses lattice structures for offshore constructions in which the 25 individual node elements at which struts adjoin legs are designed as separate components. The object of the invention is therefore to further develop a jacket such that it can be produced more 30 simply and more cost-effectively and nevertheless meets all the requirements for an offshore foundation structure. In addition, the object of the invention is to propose a production and assembly method for such a jacket. 35 2582577v1 WO 2015/032495 -4- PCT/EP2014/002387 The invention achieves the stated object with a jacket for a wind turbine as claimed in the preamble to claim 1, which is characterized in that, the different region of the legs, in each case two struts meet the leg which 5 only extend to one of the adjacent legs. In the case of a jacket as claimed in claim 1, the struts and legs are consequently arranged such that, at least over the majority of the length L, struts are arranged between the legs which do not cross any other struts. As a 10 result of this simple measure, it is surprisingly achieved that the manufacturing tolerances which need to be observed during the production of the struts can be chosen to be considerably more generous. In particular the length of the struts does not need to be 15 worked so precisely. If, for example, one of the struts is not delivered to the precise desired length and instead its length deviates somewhat, the angle of inclination of the 20 relevant struts between the two relevant legs can be altered simply without this having any disadvantageous effects on the structural performance of the jacket. This is not possible when the struts are crossed. 25 According to the invention, the struts are intended to be arranged at least over the majority of the length L in such a way that they do not cross one another. The majority of the length L here means at least half, advantageously %, particularly preferably 4/5 of the 30 length L. Optimally, the struts are arranged accordingly over the whole length L of the legs so that they do not cross one another. For structural reasons, the respective bottom jacket segment which is connected to the piles in the sea bed can here form an exception 35 such that a jacket segment which has crossed struts can be present in the region of the sea bed. 2582577v1 WO 2015/032495 -5- PCT/EP2014/002387 In a particularly preferred embodiment, the jacket can, at least theoretically, be broken down into essentially K-shaped components at least over the majority of the 5 length L. As a result, not only are the already described advantages of the struts which do not cross one another realized but it is also achieved that, at the points of the legs of the jacket at which struts are arranged, the struts arranged at the respective leg 10 all lead away from the respective leg within the same plane. In the case of jackets with crossed struts, as already explained, in many regions of the legs four struts need 15 to be fastened to the respective leg in a very small space. Two of the struts here extend to the right-hand neighboring leg of the respective leg, and two of the struts extend to the left-hand neighboring leg. If the jacket, as claimed in this preferred embodiment, can be 20 broken down, at least theoretically, into essentially K-shaped components, this does not occur. At the points of the legs at which the struts are arranged, only two struts join the respective leg which are both connected to the right-hand neighboring leg or the left-hand 25 neighboring leg. As a result it is also considerably easier to produce and prefabricate the individual parts for the jacket and construction is made quicker. Advantageously, only inclined struts are present in 30 such a jacket. In this case, inclined means that they are arranged neither vertically, i.e. following the laws of gravity, nor horizontally, i.e. at right angles to the vertical. A high torsional and flexural rigidity of the jacket is achieved as a result. All the struts 35 in particular have an angle of inclination of more than 50 degrees to the vertical. 2582577v1 WO 2015/032495 -6- PCT/EP2014/002387 Advantageously, a vertical and/or a horizontal connection is arranged between in each case two struts. The torsional strength and stability of the jacket is 5 increased as a result. The connections between the individual struts are considerably shorter than the required segments of the legs or the length of the struts so that they can be produced considerably more simply with the low tolerances demanded. 10 It has proven to be advantageous if the vertical and/or horizontal connections are arranged in the middle of the respective struts. A connection arranged in the middle of the struts is consequently situated half way 15 along the strut from one leg to the other leg of the jacket. If vertical connections are arranged in each case between all the struts which are situated between two 20 neighboring struts, a vertical structure results which extends almost over the entire length L of the legs of the jacket. In contrast, horizontal connections which are arranged between individual struts create, depending on the number of legs of the jacket, polygons 25 which are arranged horizontally and considerably increase the torsional rigidity of the jacket. If the jacket has, for example, three legs, triangles are created by horizontal connections between the individual struts and, in addition to increasing the 30 torsional rigidity, also ensure that oscillations of the struts are also damped or prevented altogether which can occur, as a result of the length of the struts and the intersection points which are missing in comparison with the crossed struts, under the action of 35 wind, waves and tides and in particular as a result of the operation of the wind turbine. In this way, not 2582577v1 WO 2015/032495 -7- PCT/EP2014/002387 only is the stability of the jacket increased but the lifetime of the jacket too because the mechanical loads which occur as a result of the oscillations are prevented or at least reduced. 5 According to the invention, in each case two struts consequently meet the respective leg at different regions of the respective legs of the jacket but always extend to only one of the neighboring legs. If the two 10 struts to be arranged are in a first region for example connecting struts to the right-hand neighboring leg, the struts to be arranged in an adjoining region are connections to the left-hand neighboring leg. 15 The legs of the jacket can, in a manner known in principle from the prior art, be connected to piles of the wind turbine in the sea bed. A transition piece which forms the transition between the jacket and a tower for the wind turbine, to be arranged on the end 20 of the jacket, can be arranged on that end of the legs opposite this connection. The legs themselves can be arranged parallel to one another or slightly inclined to one another so that the jacket tapers upward. The jacket advantageously has three or four legs. However, 25 jackets with a greater number, for example six, eight or ten legs, are also possible. The invention achieves the stated object with a method for producing such a jacket in a lying position which 30 is characterized in that the method has the following steps: a) positioning a first leg and a second leg at a predetermined distance from each other, b) positioning multiple struts between the first leg 35 and the second leg, 2582577v1 WO 2015/032495 -8- PCT/EP2014/002387 c) connecting the struts to the first leg and the second leg to make a first part structure, d) positioning at least one third leg above the first part structure, 5 e) positioning multiple struts between the first part structure and the at least one third leg, f) connecting the struts to the first part structure and the at least one third leg. 10 In this way, in particular jackets with three legs can be produced in a particularly simple, quick and hence cost-effective manner. The first leg and the second leg are first positioned at a predetermined distance from each other. This can take place on work benches, work 15 tables or the floor of the production hall. The first leg and/or the second leg can here be assembled from multiple leg segments which were, for example, produced and prepared separately and in advance. The regions in which struts are intended to be arranged on the 20 respective leg can here be designed, for example, with a thicker wall in order to achieve the required stability in this region and make savings in material between these so-called node regions. The individual leg segments can here have a length of 10 to 25 meters 25 and be assembled for the method step a). The struts which are positioned between the legs are advantageously likewise delivered ready-to-fit. They can, for example, consist of a middle region and two 30 end pieces arranged at its ends, wherein the middle region can, for example, have a length of 18 meters. In the middle region, the strut is a steel tube with a predetermined wall thickness which is adapted to the loads which are to be expected and the length of the 35 strut. An end piece, which is welded on one side to the respective end of the middle region, can be placed on 2582577v1 WO 2015/032495 -9- PCT/EP2014/002387 each of the ends of this middle region. The weld here is an orbital weld which can be produced simply, quickly and cost-effectively. The other end of the respective end piece has been prepared in advance for a 5 contour weld and has the corresponding structure. The struts are positioned in method step b) between the two legs to which they are intended to be fastened. Manufacturing tolerances of up to 20 mm can here be 10 compensated easily by the angle of inclination at which the strut is arranged on the respective leg being adapted to the length of the strut. The struts positioned in this way are held securely in position and are then connected by a contour weld to the first 15 leg and the second leg to make a first part structure. If it is intended to produce a jacket with only three legs, the third leg is then arranged above this first produced part structure, it being held in position, for 20 example, by supporting frames. The struts are then arranged in the same way between this first part structure and the at least one third leg, and manufacturing tolerances are compensated accordingly. 25 Anchoring sleeves, which make it possible for the jacket to be connected later to piles situated in the sea bed, can, for example, be arranged at the lower end of the respective legs at the beginning or at the end. 30 In method step d) a second part structure consisting of a third leg, a fourth leg and multiple struts which are connected to the third leg and the fourth leg is advantageously positioned above the first part structure. In this way, a jacket with four legs can be 35 produced simply. The second part structure is here produced in a similar fashion to the first part 2582577v1 WO 2015/032495 -10- PCT/EP2014/002387 structure and then fastened in the desired position, for example by supporting frames or from cranes suspended from the ceiling. The subsequent positioning of the struts and connecting of the struts to the two 5 part structures functions in a similar fashion to the already described method. It has proven to be particularly advantageous if multiple connecting pieces are arranged on the first 10 leg and on the second leg and if the first leg and the second leg are arranged in method step a) at a distance from each other that is so great that the struts can be threaded onto the connecting pieces in method step b). 15 In this embodiment of the method too, leg segments can again be delivered ready-to-fit. Here too the legs consist of node regions at which they are intended to be connected to struts, and intermediate regions which can have a smaller wall thickness compared with the 20 node regions. The delivery length of corresponding leg segments can again be between 10 and 25 meters. Connecting pieces which are arranged with contour welds in the respective desired angle on the respective leg 25 segment are situated in the node regions of the leg segments. The struts themselves can in this case take the form of simple tubes which do not need to have special end 30 pieces. The struts advantageously take the form of welded hollow tubes, the internal diameter of which is large enough to allow the respective hollow tube which forms the strut to be threaded onto the connecting piece. This threading onto the connecting pieces forms 35 method step b) in which the struts are positioned relative to the first leg and the second leg. The 2582577v1 WO 2015/032495 -11 - PCT/EP2014/002387 connecting pieces opposite each other on the first leg and on the second leg, which are intended to together form the same strut, advantageously have different lengths so that it is possible to thread the strut on 5 easily in such a way that it, in the form of a hollow tube, surrounds each one of the connecting pieces at both ends and is thus positioned between the two legs of the jacket. However, the strut can here be displaced in its longitudinal direction and can be brought into 10 the desired position. In method step c), before the struts are connected to the first leg and the second leg, the first leg and the second leg are preferably moved toward each other. The 15 distance between the two legs is thus reduced so much that the struts can no longer be detached from the connecting pieces. In method step c), the struts are then connected to the connecting pieces and thus also to the leg segments and the legs of the jacket. In this 20 way, manufacturing tolerances in the length of the struts can be compensated particularly simply because there is no longer any need for a precise contour weld between the strut and the leg segment or the leg of the jacket. Instead, the respective strut is welded at both 25 its ends to the respective connecting piece of the leg by an orbital weld which can take place at almost any position along the length of the connecting piece. Multiple connecting pieces are advantageously arranged 30 on the at least one third leg, wherein the at least one third leg and the first part structure are arranged in method step d) at a distance from each other that is large enough to allow the struts to be threaded onto the connecting pieces in method step e). 35 2582577v1 WO 2015/032495 -12- PCT/EP2014/002387 It has in addition proved advantageous if, before the struts are connected to the first part structure and to the at least one third leg, in method step f) the at least one third leg and the first part structure are 5 moved toward each other. The threading and connecting of the struts to the connecting pieces or the respective leg here happen in a similar fashion to the abovedescribed procedure. This 10 is of course also possible if a second part structure, which is preferably produced like the already described first part structure, is used instead of a third leg. The legs of the second part structure consequently also have the already described connecting pieces. 15 If the connecting pieces described here are used in order to receive the struts and are introduced into the struts in the form of hollow tubes, the two connecting pieces, which are present for each strut, can have an 20 identical design. It is, however, also possible for them to be designed, for example, with different lengths or with a different inclination of the end face. It is thus in particular possible to design one of the two connecting pieces with a retaining bracket, 25 the end face of which is in particular inclined on one side in order thus to facilitate the threading of the strut onto the respective connecting piece. The invention achieves the stated object in addition by 30 a method for producing a jacket described here in an upright position, wherein the jacket tapers upward and the jacket is produced from multiple annular segments with different diameters, which in each case have at least one leg segment of each of the at least three 35 legs and in each case of the at least one strut 2582577v1 WO 2015/032495 -13- PCT/EP2014/002387 arranged between two neighboring legs, wherein the method has the following steps: A) positioning the annular segments to be assembled in such a way that each of the annular segments 5 surrounds the annular segments with a smaller diameter, B) lifting up the respective largest unassembled annular segment of the annular segments positioned in this way, 10 C) depositing the respective lifted-up annular segment on the respective previous annular segment, and D) repeating steps b) and c) until all the annular segments are arranged one on top of the other. 15 This manner of producing the jacket is advantageous in particular when erecting, for example, wind turbines on land. The individual annular segments are placed one on top of the other so that the individual leg segments 20 which are contained inside the different annular segments can be fastened to one another in such a way that they together form the legs of the jacket. Because the jacket tapers upward, all the annular segments have different diameters so that they can be nested one 25 inside the other. Thus each annular segment surrounds the annular segments which have a smaller diameter and hence need to be arranged at a higher position of the erected jacket. 30 In this way, a space-saving arrangement of the individual annular segments can be obtained, wherein the segments are additionally arranged in the correct order. In order to erect the respective jacket, in each case the largest of these annular segments which 35 consequently surrounds all the other as yet unassembled 2582577v1 WO 2015/032495 -14- PCT/EP2014/002387 annular segments must now be lifted up and positioned and fastened on the previous annular segment. In a preferred embodiment, the annular segments to be 5 assembled are arranged inside a base annular segment. This base annular segment, which is for example arranged on concrete piles embedded in the ground, consequently has the largest diameter of the individual annular segments. The next largest annular segment, 10 which needs to be lifted up first, is then lifted up from its storage place, which is situated inside the base annular segment, and positioned with its leg segments on the leg segments of the base annular segment. To do this, it may need to be turned a little 15 in order to be able to move the individual leg segments of the different annular segments past each other. By virtue of a jacket according to an exemplary embodiment of the present invention, an easy-to 20 assemble, easily dismantlable solution for a jacket which is cost-effective to install is consequently proposed. In a particularly preferred embodiment, for example the connections which are arranged between the individual struts can be connected to these struts not 25 only rigidly but also, for example, via a joint. In this way, the oscillations, of the often long struts, which are caused in particular also by the operation of the wind turbine itself are considerably better reduced and thus the mechanical stress on the weld seams is 30 also considerably reduced. An exemplary embodiment of the present invention is explained in detail below with the aid of drawings, in which: 2582577v1 WO 2015/032495 -15- PCT/EP2014/002387 Figure 1 shows the schematic view of a 3-legged jacket according to a first exemplary embodiment of the present invention, Figure 2 shows the schematic view of a leg segment, 5 Figures 3a and 3b show two different embodiments of a connecting piece, Figures 4a to 4d show the schematic view of different states in the threading of a strut onto the connecting pieces, 10 Figure 5 shows the schematic view of threaded struts between two legs, Figures 6a and 6b show the schematic view of a jacket before and after the lowering of the third leg, Figures 7a and 7b show the schematic view of a leg 15 segment and a strut, Figure 8 shows the schematic view of struts arranged between two legs, Figures 9a to 9d show different stages in the positioning of a strut between two legs, 20 Figure 10 shows the schematic view of a base annular segment, and Figure 11 shows the schematic view of a partially constructed jacket. 25 Figure 1 shows a jacket 1 according to a first exemplary embodiment of the present invention. The jacket has three legs 2 between which multiple struts 4 are arranged. It can be seen that in each case 30 there are always just two struts 4 connected to the respective leg 2 in a node region 6 in which struts 4 are connected to the respective leg 2. These two struts 4 connect the leg 2 in which the node region 6 is situated to either the right-hand or the left-hand 35 neighboring leg 2, but never to different neighboring legs 2. 2582577v1 WO 2015/032495 -16- PCT/EP2014/002387 The struts 4 are arranged such that they do not cross one another over the whole length L of the legs 2. As a result, the manufacturing tolerances can be compensated 5 considerably better. Anchor sleeves 8, through which the piles 10 can be driven into the sea bed 12, are arranged in the lower region of the legs 2. A connecting element 14, which 10 establishes a connection of the jacket 1 to a tower 16 (just the beginning of which is shown in dashed lines) of the wind turbine, is situated at the upper end of the legs 2. 15 The jacket 1 shown in Figure 1 can in theory be disassembled into multiple K-shaped individual parts. Figure 2 shows a leg segment 18 which consists of node regions 6 and intermediate regions 20. The internal 20 diameter of the respective node regions 6 or intermediate regions 20 is shown by dashed lines. It can be seen that the leg segment 18 has a lower wall thickness in the region of the intermediate regions 20 than in the region of the node regions 6. However, if 25 it is structurally adequate, the node regions 6 and the intermediate regions 20 can also be produced with the same wall thickness, preferably the thin wall thickness of the intermediate regions 20. The production process is simplified as a result. 30 In each case two connecting pieces 22, which are connected via in each case a contour weld to the node region 6 of the leg segment 18, are arranged in the node regions 6. 35 2582577v1 WO 2015/032495 -17- PCT/EP2014/002387 Two different connecting pieces 22 are shown in Figures 3a and 3b. Whilst the connecting piece 22 shown in Figure 3a has an inner collar 24 which projects from the connecting piece 22, the connecting piece 22 shown 5 in Figure 3b, as well as the inner collar 24, additionally has a retaining bracket 26 which has an inclined end face 28, which can have an annular design. In a preferred embodiment, the connecting pieces 22 10 shown in Figures 3a and 3b are used in order to receive the two ends of a strut 4 and be connected to these ends. Different stages of this connection are shown in Figures 4a to 4d. 15 Two legs 2, each with a connecting piece 22 arranged thereon, can be seen in Figure 4a, wherein the left hand connecting piece 22 corresponds to the connecting piece 22 shown in Figure 3a and has a protruding inner collar 24, whilst the right-hand connecting piece 22 20 shown in Figure 4a additionally has the retaining bracket 26 and corresponds to the connecting piece 22 shown in Figure 3b. A strut 4, which is first threaded obliquely onto the 25 retaining bracket 26 of the right-hand connecting piece 22, is positioned between the two connecting pieces 22. The point in time shortly before this threading is shown in Figure 4b. 30 Figure 4c shows that the strut 4 bears on both inner collars 24 or the retaining bracket 26. The strut 4 is threaded onto the retaining bracket 26 and pushed onto the inner collar 24 of the right-hand connecting piece 22 until a left-hand end 30 of the strut 4 can slide 35 past the inner collar 24 of the left-hand connecting piece 22. The strut 4 is then, as shown in Figure 4c, 2582577v1 WO 2015/032495 -18- PCT/EP2014/002387 pushed to the left and then bears on the inner collar 24 of the left-hand connecting piece 22. The two legs 2 are then pushed toward each other so that the distance between the two legs 2 is reduced and the strut 4 then 5 bears on both inner collars 24 of both connecting pieces 22. In this state, the strut 4 is connected to the respective inner collar 24 by a simple orbital weld. Because the actual position of this weld seam plays almost no part in the stability of the device, 10 manufacturing tolerances, in particular for the length of the strut 4, can be compensated simply in this way. Figure 5 shows the decisive step in a different view. Two leg segments 18 can be seen, with in each case two 15 connecting pieces 22 arranged thereon. A strut 4 is shown in dashed lines, situated between the left-hand leg segment 18 and the right-hand leg segment 18, its connecting pieces 22 also being shown in dashed lines. In this position, the two leg segments 18 have been 20 positioned in method step a) . This distance is great enough to allow the strut 4, as shown in Figures 4a to 4d, to be threaded onto the connecting pieces 22 or their inner collars 24. 25 The leg segments 18 or the legs 2 are then moved toward one another so that the leg segment 18 shown on the right-hand side in Figure 5 is now arranged in the position moved to the right, in which its connecting pieces 22 are shown in solid lines. On the strut 4, 30 which is now welded to the connecting pieces 22, is shown in solid lines. In this way, a first part structure 32 can be created which consists of two legs 2 and struts 4 arranged between them. This first part structure 32 is shown lying on the floor in Figure 6a. 35 A third leg 36 is held in a position above the first part structure 22 via two schematically shown supports 2582577v1 WO 2015/032495 -19- PCT/EP2014/002387 34. This distance too is great enough to allow struts 4 to be threaded onto connecting pieces 22 which are situated on the legs 2 of the first part structure 32 and on the third leg 36. The elevated holding position 5 of the third leg 36 and of the corresponding struts 4 is shown here in solid lines. The final desired position of both the third leg 36 and the struts 4 is shown in dashed lines. 10 This view is reversed in Figure 6b. It can be seen that the supports 34 are lowered so that the effect shown in Figure 4d occurs and the struts 4 now end flush with the connecting pieces 22 and in this state can be connected to the connecting pieces 22. 15 Instead of the third leg 36 shown in Figures 6a and 6b, a second part structure can of course also be used, which for example likewise consists of two legs 2 and struts 4 arranged between them. 20 Figure 7a and Figure 7b show a leg segment 18 and a strut 4 for a different exemplary embodiment of a method for constructing a jacket 1 described here. The leg segment 18 again consists of node regions 6 and 25 intermediate regions 20, wherein the intermediate regions 20 again have a smaller wall thickness than the node regions 6. The struts 4, however, consist of a middle region 38 and two end pieces 40 arranged at its ends. The end pieces 40 and the middle region 38 are 30 connected by an orbital weld seam which is easy to produce. The end pieces 40 are prepared at their end 42 furthest from the middle region 38 so as to be arranged by a contour weld at the node region 6 of the leg segment 18. 35 2582577v1 WO 2015/032495 -20- PCT/EP2014/002387 This situation is shown in Figure 8. The two leg segments 18 with node regions 6 and intermediate regions 20 can be seen. A strut 4, the end pieces 40 of which are connected to the respective node region 6, is 5 arranged between two node regions 6 of the two leg segments 18. Dashed lines show how manufacturing tolerances can be compensated in this case. Whilst the strut 4 shown in solid lines has the optimum length to be fastened between the two leg segments 18, the strut 10 4 shown in dashed lines has a somewhat longer design. In this highly exaggerated example, it can be seen that such manufacturing tolerances can be readily compensated by simply changing the angle of inclination of the strut 4. 15 By virtue of a jacket 1 according to an exemplary embodiment of the present invention described here, it is possible to achieve an angle of inclination of at all times more than 500 to the vertical. 20 The different stages in the positioning of the strut 4 between the legs 2 are shown in Figures 9a to 9d. As shown in Figure 9a, the two legs 2 are first positioned at a desired distance from each other. In this case, 25 this distance corresponds to the final distance so that the two legs 2 do not need to be moved toward each other at a later stage of the method. A movable lug 44 is arranged at the desired points at which it is intended to make a connection between a strut 4 and the 30 leg 2. A strut 4 is then placed against the upper lug 44 in Figure 9b and, as shown in Figure 9b, past the lower lug 44, leaning against the leg 2. As shown in Figure 9c, the ends of the strut 4 are then fixed in position on the lugs 44 by a retainer 46. After the 35 lugs 44 have been removed, the ends of the strut 4 can 2582577v1 WO 2015/032495 -21 - PCT/EP2014/002387 be fastened to the legs 2 and the retainer 46 then removed. The finished state is shown in Figure 9d. Figure 10 shows a first portion of a jacket 1 that is 5 intended to be produced on land, i.e. onshore. It has eight legs 2, one leg segment 18 of which is shown in each case. The leg segments 18 are connected to piles 48 which are embedded firmly in the ground. A base annular segment 50 is shown in Figure 10 which consists 10 in each case of a leg segment 18 for each of the legs 2 and in each case two struts 4 arranged between these leg segments 18. Figure 11 shows schematically how an onshore jacket 1 15 of this type is produced. The piles 48 on which the base annular segment 50 stands can be seen. Further annular segments 52 are first arranged next to the base annular segment 50, to the right of it in Figure 11. The individual annular segments 52 here stand one 20 inside the other, which is readily possible because the jacket 1 tapers upward and thus each of the annular segments 52 has a different diameter. In order to construct the jacket 1, in each case the outermost of the as yet unassembled annular segments 52 is then 25 lifted up and placed on the respective last assembled annular segment 52, in other words firstly on the base annular segment 50, and fastened to it. In this way, the complete jacket can be erected simply without there being any need for a large floor area or a large 30 storage space for the different components and in particular the annular segments 52. In another embodiment of this method, all the annular segments 52 are arranged inside the base annular 35 segment 50. As a result, the space required to carry out the method is further reduced. 2582577v1 WO 2015/032495 -22- PCT/EP2014/002387 List of reference numerals 1 jacket 2 leg 5 4 strut 6 node region 8 anchor sleeve 10 pile 12 sea bed 10 14 connecting element 16 tower 18 leg segment 20 intermediate region 21 connecting piece 15 24 inner collar 26 retaining bracket 28 end face 30 left-hand end 32 first part structure 20 34 support 36 third leg 38 middle region 40 end piece 42 end 25 44 lug 46 retainer 48 pile 50 base annular segment 52 annular segment 30 2582577v1

Claims

1. A jacket (1) for a wind turbine which has at least three legs (2) of a length L and multiple struts 5 (4) which each extend between two legs (2), wherein at least over the majority of the length L struts (4) are arranged between the legs (2) and do not cross any other struts (4), characterized in that in each of different 10 regions of the legs (2) two struts (4) meet the leg (2) which only extend to one of the adjacent legs (2).

2. The jacket (1) as claimed in claim 1, 15 characterized in that the jacket (1) can, at least theoretically, be broken down into essentially K-shaped components at least over the majority of the length L. 20

3. The jacket (1) as claimed in claim 1 or 2, characterized in that a vertical and/or horizontal connection is arranged between in each case two struts (4). 25

4. The jacket (1) as claimed in claim 3, characterized in that the vertical and/or horizontal connections are arranged at the middle of the respective struts (4). 30

5. A method for producing a jacket (1) as claimed in one of the preceding claims in a lying position, characterized in that the method has the following steps: a) positioning a first leg (2) and a second leg (2) 35 at a predetermined distance from each other, 2582577vl WO 2015/032495 -24- PCT/EP2014/002387 b) positioning multiple struts (4) between the first leg (2) and the second leg (2), c) connecting the struts (4) to the first leg (2) and the second leg (2) to make a first part structure 5 (32), d) positioning at least one third leg (36) above the first part structure (32), e) positioning multiple struts (4) between the first part structure (32) and the at least one third 10 leg (36), f) connecting the struts (4) to the first part structure (32) and the at least one third leg (36). 15

6. The method as claimed in claim 5, characterized in that in method step d) a second part structure consisting of the third leg (36), a fourth leg (2) and multiple struts (4) which are connected to the third leg (36) and the fourth leg (2) is 20 positioned above the first part structure (32).

7. The method as claimed in claim 5 or 6, characterized in that multiple connecting pieces (22) are arranged on the first leg (2) and on the 25 second leg (2), and in that the first leg (2) and the second leg (2) are arranged in method step a) at a distance from each other that is large enough to allow the struts (4) to be threaded onto the connecting pieces (22) in method step 30 b).

8. The method as claimed in claim 7, characterized in that, before the struts (4) are connected to the first leg (2) and the second leg (2), in method 35 step c) the first leg (2) and the second leg (2) are moved toward each other. 2582577vl WO 2015/032495 -25- PCT/EP2014/002387

9. The method as claimed in one of claims 5 to 8, characterized in that multiple connecting pieces (22) are arranged on the at least one third leg 5 (36), and in that the at least one third leg (36) and the first part structure (32) are arranged in method step d) at a distance from each other that is large enough to allow the struts (4) to be threaded onto the connecting pieces (22) in 10 method step e).

10. The method as claimed in claim 9, characterized in that, before the struts (4) are connected to the first part structure (32) and to the at least 15 one third leg (36), in method step f) the at least one third leg (36) and the first part structure (32) are moved toward each other.

11. The method for producing a jacket (1) as 20 claimed in one of claims 1 to 4 in an upright position, wherein the jacket (1) tapers upward and the jacket (1) is produced from multiple annular segments (52) with different diameters, which in each case have at least one leg segment 25 (18) of each of the at least three legs (2) and at least one strut (4) arranged between two neighboring legs (2), wherein the method has the following steps: A) positioning the annular segments (52) to be 30 assembled in such a way that each of the annular segments (52) surrounds the annular segments (52) with a smaller diameter, B) lifting up the respective largest unassembled annular segment (52) of the annular segments (52) 35 positioned in this way, 2582577vl WO 2015/032495 -26- PCT/EP2014/002387 C) depositing the lifted-up annular segment (52) on the respective previous annular segment (52), D) repeating steps B) and C) until all the annular segments (52) are arranged one on top of the 5 other.

12. The method as claimed in claim 11, characterized in that the annular segments (52) to be assembled are positioned inside a base 10 annular segment (50). 2582577vl