FOUNDATION FOR A WIND TURBINE

Description

[0001] The invention relates to a foundation for a wind turbine, wherein the foundation comprises substantially prefabricated elements, preferably made of reinforced concrete, with a first, vertically extending, base-like section on which a tower of the wind turbine can be arranged, with a second, substantially horizontally extending section as a foundation body, which is in contact with the ground and which has at least two horizontal elements with at least one support section at its inner end, wherein the first section is arranged above the at least two support sections of the second section, and with a third section which is arranged below the at least two support sections of the second section.

[0002] Foundations for wind turbines are essentially constructed as in-situ concrete foundations. For this purpose, a pit is excavated at the construction site and covered with a blinding layer. The formwork and reinforcement are then erected and the entire structure is filled with concrete on site. This involves constructing a flat structure, possibly with a base, see, for example, US 20160369520 A1 or WO 2008 / 036934 A2. In addition to the transport costs associated with delivering the concrete, formwork, and reinforcement, this on-site construction is very labor-intensive. Quality assurance is also complex and, depending on the weather, can also be problematic. Furthermore, dismantling after the end of the wind turbine's service life is expensive and very time-consuming. This is particularly true for concrete towers for wind turbines, which ideally have a diameter-to-height ratio of approximately 1:10, making diameters of 8 to 15 m not uncommon.Foundations for such towers are currently cast in-situ. Furthermore, areas must be provided where the tower's prestressing elements can be attached to the foundation and prestressed. Prestressing is carried out using dedicated fixtures that must be placed in the prestressing areas. Complex cantilever structures are usually provided inside the foundation as abutments for prestressing or for attaching the prestressing elements (strands / cables), beneath which the fixtures are then placed. These structures are complex and in need of improvement.

[0003] Furthermore, there is a fundamental need to construct wind turbine foundations from prefabricated elements, which could reduce or eliminate the aforementioned problems. In principle, prefabrication offers the advantage of standardized production of components under defined conditions. It also reduces the labor required on-site. Various approaches have been described in the state of the art for this purpose.

[0004] For example, WO 2008 / 036934 A2 shows a combination of prefabricated elements and traditional formwork / reinforcement construction. This only marginally reduces the aforementioned disadvantages.

[0005] Further approaches to producing foundations for wind turbines from prefabricated components are shown in the prior art as follows: EP 1 058 787 B1 discloses a foundation for a wind turbine for erecting offshore wind turbines, which are transported fully pre-assembled - i.e., including the foundation - and placed in one piece on the seabed at the installation site. The foundation has individual prefabricated segments. These can be made of concrete. A flat section and a base section are disclosed. The base section consists of circular rings. The flat section consists of individual base elements with a trapezoidal base area, on which the base section, which has vertical passages, is mounted vertically at the inner end. The flat base sections are connected to one another by means of tongue and groove joints.The base section and the flat base section are connected with a diagonal brace for reinforcement. The circular segments of the base section also have vertical passages. Connecting cables / anchor rods are inserted into these passages. If the foundation elements are to be made of concrete, a flat steel abutment ring is provided below the base elements in the area of ​​the vertical passages. The foundation is assembled with the connecting cables / anchor rods and the wind turbine is attached to the foundation. In addition, horizontal passages are provided in the base elements and diagonal braces, in which connecting cables / anchor rods are also arranged, which are used to horizontally prestress the foundation elements. Only through horizontal prestressing is the foundation ready to bear loads.Thus, EP 1 058 787 B1 discloses a foundation made of individual prefabricated concrete parts, with a surface section and a base section, wherein at least these two sections are connected to each other vertically and horizontally.

[0006] The disadvantage here is that considerable costs and considerable labor are required to connect the elements and to create the statically load-bearing foundation.

[0007] EP 1 074 663 A1 discloses a foundation for a wind turbine comprising a central body as a base with laterally extending, star-shaped ribs / projections / beams bolted to it. The ribs and central body are bolted together horizontally on site. The components are prefabricated from concrete, among other materials, and are delivered to the construction site by truck, positioned by crane, and connected horizontally on site via flanges and bolts. Furthermore, anchors are required on the outside of the ribs to ensure sufficient load transfer.

[0008] The disadvantage here is that connecting the elements and creating a structurally sound foundation requires considerable costs and labor. Furthermore, additional anchoring is necessary.

[0009] WO 2004 / 101898 A2 discloses a foundation for a wind turbine made of prefabricated concrete components, wherein either a central body is provided to which flat bodies are screwed horizontally, or the foundation consists exclusively of components which have both a flat section and a base-like section, which are then connected horizontally to one another by screwing against flanges.

[0010] The disadvantage here is that considerable costs and considerable labor are required to connect the elements and to create the statically load-bearing foundation.

[0011] EP 2 182 201 A1 discloses two different foundations for a wind turbine. In both cases, a foundation is constructed from prefabricated concrete components following on-site delivery. Both comprise a flat section and a base-like section. Variant 1 features a central body. The ribs / flat elements are attached to this. When assembled, the ribs form a polygonal body. The central body has a projection encompassed by a corresponding recess on the ribs. The ribs are additionally secured to the central body by means of a lashing ring. Anchor rods for mounting the tower are provided on the flat elements. In the second variant, the ribs feature horizontally projecting anchor elements which, when assembled, extend radially into the center of the foundation. Plates are provided below and above the anchors.In-situ concrete is poured into the resulting cavity to connect the anchors and form a central body. Both variants simplify horizontal connection. However, both the ribs and the central body have dimensions and masses that make transport complicated.

[0012] WO 2017 / 141095 A1 and WO 2017 / 141098 A1 also disclose a foundation for a wind turbine. This foundation is formed from prefabricated rib bodies, which have a base section at their inner end, on which the wind turbine tower is mounted. The ribs extend radially outward. In another embodiment, the sections between the ribs are filled with plate elements that are bolted to the ribs with flanges to create a plate. Instead of a central body, a steel sleeve is provided in the center, which is connected to reinforcements provided inside the ribs and reinforcing beams provided in the inner cavity. The ribs have a base plate on which a diagonal reinforcement element and the base section are arranged in one piece. The base sections are connected horizontally to one another via tongue and groove elements.Furthermore, the base sections have horizontal openings in which tensioning elements are provided for horizontally connecting the base sections. Furthermore, anchor rods for connecting the tower to the foundation are cast into the base sections. External ground anchors are also disclosed.

[0013] The disadvantage here is that considerable costs and considerable labor are required to connect the elements and to create the statically load-bearing foundation.

[0014] WO 2019 / 115622 A1 and WO 2019 / 201714 A2 disclose the first successful foundations for wind turbines made of precast concrete elements for a steel tower and for a concrete tower for a wind turbine. The foundations have two sections. Rib elements are provided, each having a central section on which a base section is provided. The tower of the wind turbine is then arranged on the base section. The base section consists of individual segments that are connected to one another. The rib elements and the base elements are braced together by means of tendons provided in openings in the central section and in the elements of the base section. Further developments of these foundations have resulted in surprising and particularly efficient improvements in the area of ​​the base. A foundation for a wind turbine according to the preamble of the claim is known from WO 2018 / 055446 A1.

[0015] The object of the invention is therefore to overcome the aforementioned disadvantages and to make foundations for wind turbines, in particular for wind turbines with concrete towers, economically erectable or more erectable from prefabricated elements.

[0016] The object of the invention is achieved in that a base is provided which is formed at least from the first, vertically extending, base-like section, from the at least two support sections of the second section and from the third, vertically extending, base-like section, in that the three sections form at least three layers arranged one above the other, of which the upper and lower layers are formed from at least two ring-like layers and the middle layer is formed from at least one ring-like layer, in that the height of the upper and / or lower layer is smaller than the height of the middle layer, and in that the layers are vertically braced to the second section by means of at least two vertical tendons.

[0017] Such foundations according to the invention are suitable for both concrete and steel towers. The advantage of this foundation is that horizontal connecting elements can be completely dispensed with, while maintaining sufficient stability even under extreme load conditions. This is surprisingly achieved in particular by the upper and lower layers of at least two ring-shaped layers in conjunction with the bracing by prestressed tendons.

[0018] A further teaching of the invention provides that the combined height of the upper and lower layers is smaller than the height of the middle layer. This surprisingly allows for optimal load distribution in the foundation.

[0019] A further teaching of the invention provides that at least one of the layers consists of at least one prefabricated element, preferably of reinforced concrete. Alternatively, at least one of the layers consists of at least two prefabricated elements, preferably of reinforced concrete. Furthermore, it is provided that at least two adjacent layers consist of at least two prefabricated elements, preferably of reinforced concrete. This facilitates the standardized construction of the foundation and reduces the necessary number of transports to the construction site, particularly for in-situ concrete.

[0020] It is advantageous that the at least two elements are arranged butt-jointed and form the ring-shaped layer without horizontal fastening means in the vertical joints between the at least two elements. It is advantageous that the vertical joints are provided in a stress-free manner and / or that the at least two elements are arranged without contact in the vertical joints. This in turn facilitates the standardized construction of the foundation and at the same time keeps costs low because the prefabricated components in the area of ​​the vertical butt joints, for example at distances of up to 3 cm, can be worked with tolerances during production that are usual in concrete construction. Surprisingly, it has also been shown that with this type of arrangement, sufficient stability is guaranteed in the foundation even under extreme load situations.

[0021] Another advantage is that the joints or vertical joints between two layers directly above each other are not aligned. Surprisingly, it has been shown that it is possible to break down the individual ring-like layers into individual elements while simultaneously achieving sufficient stability in the foundation, even under extreme load conditions.

[0022] A further teaching of the invention provides that the prefabricated elements of the first and / or second section are arranged so as to be connected to one another essentially without horizontal connecting means, preferably with a vertical distance between the prefabricated elements.

[0023] A further teaching of the invention provides that the prefabricated elements of the lower and / or upper layer have reinforced reinforcement in the normal direction (tensile / compressive reinforcement) and / or that the prefabricated elements of the middle layer have at least one reinforced reinforcement for dissipating shear loads, in particular in the radial direction. The provision of the reinforcements in the manner described above enables a cost-effective construction of the foundation.

[0024] A further teaching of the invention provides that at least one horizontal joint between the prefabricated elements of the first and / or second section is arranged on top of one another without in-situ concrete and / or mortar. It has been shown that providing horizontal contact between the prefabricated elements with sufficiently precise manufacturing (small tolerances in the horizontal direction of the prefabricated elements) creates sufficient friction in the horizontal joints through the prestressing, thus ensuring sufficient stability in the foundation even under extreme load conditions.

[0025] A further teaching of the invention provides that the prestressing by the at least two tendons is designed such that all horizontal joints between the layers are under pressure in every operating condition and under every extreme load condition of the wind turbine. This creates sufficient friction between the prefabricated elements, particularly in the horizontal joints between the prefabricated elements, in a particularly simple manner, so that the foundation, even without integral joints, provides sufficient stability at the horizontal joints, even under extreme load conditions.

[0026] A further teaching of the invention provides that at least two ring-shaped abutments, preferably in the form of at least one abutment ring, are provided against which the tendons act, with at least one abutment being arranged on the upper side of the first section and at least one abutment on the lower side of the third section. This provides the necessary load abutment for the tendons and the prestressing introduced via them in a simple manner. It is advantageous that at least one abutment and / or at least one abutment ring consists of at least two prefabricated elements that are arranged abutting to form the ring-shaped abutment and / or abutment ring. This facilitates the transport of the prefabricated elements. It is also advantageous that at least one abutment has at least two layers arranged one above the other.This makes it possible to construct the foundation in a standardized manner, depending on the applied prestressing. Another advantage is that each layer has at least two elements arranged in a butt joint, whereby the joints between two layers directly above one another are not aligned. This avoids complex welding work on site and reduces the foundation construction time. Furthermore, it is easy to adequately transfer the prestressing loads via the abutment constructed in this way, depending on the foundation design.

[0027] A further teaching of the invention provides that the second section is formed from at least three horizontal elements, and that the horizontal elements can be arranged depending on the parameters of the tower to be erected, in particular the tower radius. It is advantageous for the horizontal elements to be arranged laterally spaced from one another, or for the horizontal elements to be arranged laterally parallel and spaced from one another. This makes it particularly easy to provide a foundation depending on the dimensions of the tower to be erected. In particular, it is possible to create foundations for different tower radii with one type of horizontal element by shifting the horizontal elements in parallel accordingly.

[0028] A further teaching of the invention provides that the elements of the at least three layers of the first section have at least two substantially vertical openings, in each of which a tendon, preferably a threaded rod or an anchor bolt with counter elements, is arranged. This makes it particularly easy to provide the foundation quickly and cost-effectively. When providing the openings, precise work with only minor deviations is necessary to ensure that the tendons can be inserted and, at the same time, to ensure that the prefabricated elements can be assembled. This is facilitated in a particularly simple way by the vertical spacing of the elements.

[0029] The invention is explained in more detail below using exemplary embodiments in conjunction with a drawing. The drawings show: Fig. 1 a sectional view of a preferred embodiment of a foundation according to the invention Fig. 2 a spatial view of Fig. 1 , Fig. 3 a top view of Fig. 1 , Fig. 4a to 4eViews of a horizontal element according to the invention, Fig. 5a a plan view of arranged surface elements of the foundation according to the invention, Fig. 5b a detailed view of Fig. 5a , Fig. 6a to 8bViews of base segments according to the invention in plan view and as a spatial view, Fig. 9a plan view of an upper abutment ring according to the invention as upper and / or lower connection for the tendons of the foundation according to the invention, Fig. 10, an abstract spatial detail view of Fig. 11 , Fig. 11 a sectional view through your embodiment of upper and lower abutment ring according to Fig. 9with mounted tendons, Fig. 12a, 12b a top view and a side view of a cover plate according to the invention, and Fig. 13a to 13d different arrangement possibilities for Fig. 5a .

[0030] In the Fig. 1 In a sectional view, a foundation 10 according to the invention is arranged in a pit 101 in the ground 100, possibly on a compacted subgrade layer 102. The foundation 10 has a first section 11, which is arranged on a second section 12. Furthermore, a third section 12a is provided below the second section 12, which is located in a depression 105 of the excavation pit 101.

[0031] The three sections 11, 12, 12a form a base 20, which in turn is constructed from several layers 13, 16, 17. Layers 13, 16, 17 here, for example, are constructed from five layers 13a, 13b, 16a, 17a, 17b. If necessary, additional layers can be provided.

[0032] The layers 13a, 13b, 17a, 17b are made up of closed base sections 14, which in turn are made up of individual base segments 33, 34, 35 (see Fig. 6a to 8b ). The base sections 14 are preferably designed as circular rings, so that the base section 11 has an interior space 15. An alternative structure, e.g., a polygonal structure, is possible.

[0033] The layers 13, 16, 17 are preferably composed of the individual layers 13a, 13b, 16a, 17a, 17b, wherein the layers 13a, 13b, 17a, 17b themselves are composed of base segments 33, 34, 35 that match the layers. The uppermost layer 13 has two layers 13a, 13b. The upper layer 13a is composed of base segments 33, for example, according to Fig. 6a, 6bwith a height H. On the upper side 36, for example, a recess 37 is provided, into which a connecting flange for the tower of the wind turbine or directly the lowest segment of the tower of the wind turbine is placed (not shown). In the recesses 37, the openings 18a for tendons (not shown) of the tower of the wind turbine are provided. Furthermore, openings 18 are provided for the tendons 19. In the area of ​​the openings 18, abutment flanges 51, for example according to Fig. 9 against which the tendons 19 are tensioned via the counter elements 21.

[0034] Below this, a layer 13b is provided, which consists of base segments 34 ( Fig. 7a, 7b) with a height I, which are also provided with openings 18 for the tendons 19 and openings 18a. The height I can be identical to the height H of the base segments 33 and is preferably the same.

[0035] Below this is layer 16a as the middle layer 16. This is formed from the bodies 30 of the support sections 25 of the horizontal segments 22. These have the height K. The bodies 30 are also provided with openings 18 for the tendons 19.

[0036] Provided below this, and thus below the horizontal elements 22, is the lower layer 17 with the layers 17a, 17b, which are formed from base segments 35 with a height J. The base segments 35 are also provided with openings 18 for the tendons 19.

[0037] The base segments 33, 34, 35 and the bodies 30 of the horizontal element 22 are preferably designed very precisely with regard to the height H, I, J, K, i.e. with the smallest possible height deviations, in order to achieve the largest possible contact surface of the base segments 33, 34, 35 and the body 30 on each other when they are mounted on the base 20 and arranged one above the other and are prestressed.

[0038] The heights H, I, and J of the base segments 33, 35 are designed such that, when installed, they are essentially subjected to tension / compression loading, i.e., loading in the normal direction. The reinforcement (not shown) is also designed for this purpose, consisting primarily of reinforcement in the normal direction. Preferably, the heights H, I, and J are equal.

[0039] The height K of the body 30 is designed so that, when installed, it is essentially subjected to shear loads only. The reinforcement (not shown) can also be designed for this purpose; it essentially consists of reinforcement in the radial direction, particularly preferably in the form of stirrups.

[0040] The arrangement of the segments 33, 34, 35 and the body 30 to form ring-like layers 13a, 13b, 16a, 17a, 17b and the arrangement of layers 13a, 13b, 16a, 17a, 17b one above the other to form the layers 13, 16, 17, which then form the base 20, is shown in Fig. 2shown spatially. The base segments 33, 34, 35 and the bodies 30 are provided butted next to one another, so that vertical joints 38, 40 exist between them. These are preferably designed as gaps, for example, with a thickness of several millimeters, e.g., 30 mm. These vertical joints 38, 40 are preferably not filled with mortar or in-situ concrete. Furthermore, horizontal connecting elements are preferably not provided.

[0041] Furthermore, the vertical joints of the individual layers 13a, 13b, 16a, 17a, 17b are preferably provided such that the vertical joints 38, 40 of adjacent layers 13a, 13b, 16a, 17a, 17b are not aligned, i.e., are not arranged one above the other. As in Fig. 2 As shown, it is advantageous if the vertical joints 38 are always arranged offset clockwise or counterclockwise by substantially the same amount.

[0042] Between the layers 13a, 13b, 16a, 17a, 17b there are horizontal joints 39, which are preferably not filled with mortar or in-situ concrete.

[0043] The base segments 33, 34, 35 and the bodies 30 have vertical openings 18, in which tendons 19, for example, anchor or reinforcement bars 19 with counter elements such as nuts 21 in conjunction with washers 21a, are provided during the assembly of the foundation 10 to prestress the foundation 10. These, together with abutments 51 composed of flange plates 52, form an anchor cage (not shown). The connection adapter 53 for the tower can also be a component of the upper abutment 51, for example, if the tower is a steel tower.

[0044] The second section 12 is flat. Alternatively, it can also be realized in a star shape. A top view of the foundation 10 is shown in Fig. 3 shown. Fig. 2shows a spatial view of the foundation 10. The second section 12 is made of horizontal elements 22 in the form of rib elements. These are shown in the Fig. 4a to 4e These extend radially outward from the interior 15.

[0045] They have a base plate 23 which is, for example, trapezoidal in shape, so that all assembled base plates form a polygonal surface (see Fig. 3 , 5a ), which approximates a circle. Alternatively, circular segments or a hybrid of circular segments and trapezoidal shapes are also possible. Distances B can preferably be provided between side walls 44 of the base plates 23, which distances depend on the diameter of the tower to be erected.

[0046] At the inner end 24 of the base plate 23, a support section 25 with a body and side walls 29 is provided, which preferably essentially corresponds to the base 20 of the first section 11. Openings 18 can also be provided in the support section 25. Alternatively, reinforcing bars or anchor rods 19 can be installed in the support section 25, aligned with the openings 18 in the first section 11, and extend outward from the concrete of the base-like section 25 of the horizontal element 22. The base 20 with its at least one base element 14 is arranged on the support section 25.

[0047] If a tower is erected using prestressing elements (not shown) and tensioned accordingly, then, as shown here, it is advantageous to provide a recess 30a in the body 30 to inspect the counter elements of the tower prestressing and re-tension them if necessary. The openings 18a preferably open into the area of ​​the recess, as shown here. Furthermore, the openings 18a are preferably inclined so that the tower's prestressing elements can be passed directly through.

[0048] The stiffening wall 26 is arranged at right angles to the base plate, the height of which decreases, for example, towards the outer end 27 of the base plate 23.

[0049] The base plate 23 is designed with a parallel taper relative to the side surfaces 29 of the body 30 of the support section 25. The parallel taper 31 is in Fig. 4crepresented by the arrow D. This preferably achieves a reduction in material. The body 30 has a transition region 32 with which the stiffening wall 26 is reinforced and connected to the support section 25.

[0050] Between the side surfaces 29 of the support sections 25, as shown in Fig. 5b as section E to Fig. 5a As shown, a distance C is preferably provided as a vertical joint 40 when the horizontal elements 22 are arranged, which is preferably designed as an air gap. This creates vertical joints 40, which are also preferably not filled with mortar or in-situ concrete. Furthermore, no horizontal connecting means are preferably provided.

[0051] Between two adjacent stiffening walls 26, an upwardly open cavity 28 is formed, into which fill soil 104 can be introduced, whereby a load can be applied to the second section 12 of the foundation 10.

[0052] In order to fill the cavities 28 with fill soil 104 and to prevent this from entering the interior space 15, blocking elements (not shown) can be placed against the body 30 of the support section 25 or the transition area 32.

[0053] Furthermore, cover plates 48 ( Fig. 12a, 12b ) are provided, which are placed on two adjacent base plates 23 to cover the distance B between two side surfaces 44 so that the soil 104 cannot penetrate into or through the distance B. The cover plates 48 have a tapered section 49 that is adapted to the transition area 32. The cover plate 48 allows the full load of the fill soil 104 to be applied to the second section 12 by introducing it into the cavity 28.

[0054] After completion of the foundation 10, the interior space 15 can be filled with fill soil 104 and covered with a cover element (not shown).

[0055] As in Fig. 13a to 13d As shown, it is possible to form a second section with a horizontal element 22, which has different sized interior spaces 15, by moving the horizontal elements 22 inwards or outwards along a ray emanating from the center, as shown in Fig. 13d is represented by the double arrow A. Inwards, this is limited by the fact that the side surfaces 44 of the base plates 23 of the horizontal elements 22 touch each other. Outwards, this depends on the radius 45 of the tower to be erected, which is in the Fig. 14a to 14drepresented by a circle 46. The distance B is preferably the same over the entire length of the side surfaces 44 from the inner end 24 to the outer end 27, so that two side surfaces 44 are arranged parallel to each other. This allows foundations for towers with different diameters to be constructed in a simple manner, preferably with a single horizontal element 22.

[0056] To provide the necessary tension between the layers 13, 16, 17 of the first, second and third sections 11, 12, 12a, an anchor cage (not shown) is formed, which consists of an upper and a lower abutment 51, which in Fig. 9 shown, which are connected to tendons 19, for example in the form of anchor rods or reinforcement rods and counter elements 21, for example nuts.

[0057] The upper and lower abutment elements 51 are composed, for example, of a 51a. The abutment ring 51a can be provided from individual flange plates 52, which are arranged butted against each other, as shown in Fig. 10 as indicated anchor cage section. Furthermore, several flange plates 52 can be arranged one above the other, as shown in Fig. 10 and Fig. 11 is shown. These are then preferably arranged such that their vertical joints 56 do not overlap in adjacent layers of flange plates 52. Preferably, the flange plates 52 are not welded to one another, but rather lie on top of or against one another. The flange plates 52 have openings 57 and can be provided with different widths and different numbers of rows of openings 57 per flange plate 52, 55.

[0058] Preferably, the abutment ring 51b can be designed integrally with the connection adapter 53 as a flange plate 52. List of reference symbols 10 foundation 34 middle base segment 11 first section 35 Base segment 12 second section 36 Top 12a third section 37 Deepening 13 upper layer 38 vertical joint 13a layer 39 horizontal joint 13b layer 40 vertical joint 14 Base section 44 side surface 15 Interior 45 radius 16 middle position 46 Circle 16a layer 48 cover plate 17 lower layer 49 tapered section 17a layer 51 abutment 17b layer 52 flange plate 18 breakthrough 56 vertical joint 19 Tendon / anchor rods 100 Floor 20 base 101 Excavation pit 21 Locking element / nut 102 Subsurface layer 21a washer 104 Backfill soil 22 Horizontal element / rib element 105 Deepening A Shift direction 23 Base plate B Distance 24 Inner end C Distance 25 Support section D Parallel taper arrow 26 stiffening wall E Excerpt 27 outer end H Height 28 cavity I Height 29 side surface J Height 30 Body K Height 30a recess 31 Parallel taper 32 Transition area 33 upper base segment

Claims

1. Foundation for a wind turbine, wherein the foundation (10) has substantially prefabricated elements, preferably composed of reinforced concrete, having a first, vertically extending pedestal-like section (11), on which a tower of the wind turbine is able to be arranged, having a second, substantially horizontally extending section (12) as a foundation body, which is in contact with the ground (100) and has at least two horizontal elements (22) with at least one bearing section (25) at the inner end thereof, wherein the first section (11) is arranged above the at least two bearing sections (25) of the second section (12), and having a third section (12a), which is arranged below the at least two bearing sections (25) of the second section (12), characterized in that provision is made of a pedestal (20) which is formed at least from the first, vertically extending pedestal-like section (11), from the at least two bearing sections (25) of the second section (12) and from the third, vertically extending pedestal-like section (12a), in that the three sections (11, 12, 12a) form at least three tiers (13, 16, 17) which are arranged one above the other and of which the upper and lower tiers (13, 17) are formed from at least two ring-like layers (13a, 13b, 17a, 17b) and the middle tier (16) is formed from at least one ring-like layer (16a), in that the height (H+I, 2x J) of the upper and / or lower tier (13, 17) is smaller than the height (K) of the middle tier (16), and in that the tiers (13, 16, 17) are vertically braced with the second section (12) by means of at least two vertical clamping members (19).

2. Foundation according to Claim 1, characterized in that the sum of the heights (H+I, 2x J) of the upper and lower tiers (13, 17) is smaller than the height (K) of the middle tier (16).

3. Foundation according to Claim 1 or 2, characterized in that at least one of the layers (13a, 13b, 16, 17a, 17b) consists of at least one prefabricated element (30, 33, 34, 35), preferably composed of reinforced concrete.

4. Foundation according to Claim 1 or 2, characterized in that at least one of the layers (13a, 13b, 16, 17a, 17b) consists of at least two prefabricated elements, preferably composed of reinforced concrete.

5. Foundation according to Claim 1 or 2, characterized in that at least two adjacent layers (13a, 13b, 16, 17a, 17b) consist of at least two prefabricated elements (30, 33, 34, 35), preferably composed of reinforced concrete.

6. Foundation according to Claim 4 or 5, characterized in that the at least two elements (30, 33, 34, 35) are arranged in a butting manner and form the ring-like layer (13a, 13b, 16, 17a, 17b) without horizontal fastening means in the vertical joints (38) between the at least two elements (30, 33, 34, 35).

7. Foundation according to Claim 6, characterized in that the vertical joints (38) are provided in a stress-free manner.

8. Foundation according to Claim 6 or 7, characterized in that the at least two elements (30, 33, 34, 35) are arranged without contact in the vertical joints (38).

9. Foundation according to one of Claims 5 to 8, characterized in that the butting means or vertical joints (38) of two layers (13a, 13b, 16, 17a, 17b) situated directly one above the other are not arranged in an aligned manner.

10. Foundation according to one of Claims 1 to 9, characterized in that the prefabricated elements (22, 33, 34, 35) of the first and / or second section (11, 12) are arranged in a manner interconnected without any horizontal connecting means.

11. Foundation according to one of Claims 1 to 10, characterized in that the prefabricated elements (22, 33, 34, 35) of the first and / or second section (11, 12) are arranged in a stress-free manner and / or without contact in the vertical joints (38, 40).

12. Foundation according to one of Claims 1 to 11, characterized in that the prefabricated elements (33, 35) of the lower and / or upper layer (13a, 13b, 17a, 17b) have a strengthened reinforcement in the normal direction (tensile / compressive reinforcement), and / or in that the prefabricated elements (34) of the middle layer (16a) have at least one strengthened reinforcement for diverting shear loads, in particular in the radial direction.

13. Foundation according to one of Claims 1 to 12, characterized in that at least one horizontal joint (38, 40) is arranged between the prefabricated elements of the first and / or second section (11, 12) in a manner in-situ-concrete-free and / or mortar-free one on top of the other.

14. Foundation according to one of Claims 1 to 13, characterized in that the prestressing by the at least two clamping members (19) is configured in such a way that all the horizontal joints (39) between the layers (13a, 13b, 16, 17a, 17b) are subjected to pressure in any operating state and in any extreme load state of the wind turbine.

15. Foundation according to one of Claims 1 to 14, characterized in that provision is made of at least two ring-like abutments (51), preferably in the form of at least one abutment ring (51a), against which the clamping members (19) act, wherein at least one abutment (51) is arranged on the top side of the first section (11) and at least one abutment (54) is arranged on the bottom side of the third section (12a).

16. Foundation according to Claim 15, characterized in that the at least one abutment (51) and / or abutment ring (51) consists of at least two prefabricated elements (52) which are arranged in an manner abutting for completion of the ring-like abutment (51) and / or the abutment ring (51a).

17. Foundation according to Claim 15 or 16, characterized in that at least one abutment (51) and / or abutment ring (51a) has at least two layers arranged one above the other.

18. Foundation according to Claim 17, characterized in that the layers have in each case at least two elements (52) which are arranged in a butting manner, wherein the butting means of two layers situated directly one above the other are not arranged in an aligned manner.

19. Foundation according to one of Claims 1 to 18, characterized in that the elements of the at least three tiers of the first section (11) have at least two substantially vertical apertures (18) in which in each case one clamping member (19), preferably a threaded rod or an anchor bolt with locking elements (21), is arranged.