WO2014037421A1

WO2014037421A1 - Tower structure of a wind power plant and method for the production thereof

Info

Publication number: WO2014037421A1
Application number: PCT/EP2013/068318
Authority: WO
Inventors: Philipp Wagner
Original assignee: Philipp Wagner
Priority date: 2012-09-04
Filing date: 2013-09-04
Publication date: 2014-03-13

Abstract

A tower structure for a wind power plant which, at least in sections, is made of concrete and is stressed by carbon fibre tendons. This minimizes the construction effort.

Description

Tower construction of a wind turbine and process to his

manufacturing

The invention relates to a tower construction of a wind energy plant and method for its production. The wind turbines (WEA) with wind generators, to which the construction according to the invention relate, have a concrete tower and mounted on the top of the tower, heavy major components. These large components are transition elements, nacelle, electric generator, rotor with at least one rotor blade and, if present, a gearbox for the rotor, and in the case of hybrid towers additional steel tube segments, which are placed on the concrete tower and carry the wind generator.

Wind turbines of different size, power and different types are spreading more and more to generate electrical energy from the kinetic energy of the wind. The effectiveness of such a wind turbine depends inter alia on the fact that the wind is distributed as long as possible and evenly over the year.

It is well known that the higher the wind turbines are built, the higher the yield of wind turbines, because at higher altitudes the wind blows faster and more laminarly on average. This is particularly the case for offshore areas, hilly or mountainous areas.

In recent years, due to economic considerations, the trend is towards ever larger plant units, with the tower structure of the hybrid tower, consisting of a concrete shaft, a transition piece and other patched steel pipe segments on which the wind generator is mounted, have prevailed. In order to obtain the necessary rigidity within the concrete shaft section, this is suppressed with tendons. The resulting Prestressed concrete component has a significantly higher rigidity than a limp reinforced concrete tower.

To realize the prestressing, in particular two tensioning methods have been applied in the past, one of which is tensioning members which run along within the concrete shank cross section where they are connected to the concrete cross section with a generally mineral filling material (internally) or at the tensioning strands on the inner wall of the tower shank be guided along (externally without composite).

A disadvantage of these designs, the weight of the tendon elements, the tendon anchors, and therefore the amount of work to install them with heavy equipment in the vertical direction, and the necessary cost of materials for the tendon anchors. This disadvantage is particularly pronounced when it comes to vollüberdrückte tower designs that work with composite dry joints and therefore the entire leverage of the free-standing cantilever must be performed by the tendons to avoid joint gap.

It is the object of the invention to propose designs for the prestressing of tower structures for wind turbines, which are easier to handle, which are lightweight, and which are easy and faster to process.

The invention provides by claim 1 a new design for towers of wind turbines, in which the bias in the tower shaft of the concrete section of the tower construction is applied via carbon fiber tendons. The tendon anchoring at both ends is realized by a tensioning method which allows a quicker and easier installation and require less design effort and assembly effort, especially at the abutments, as conventional tendons of prestressing steel and their tensioning.

The transition elements are, for example, attached to the tower shaft in the region of its upper end intermediate flanges, in particular of metal, or directly steel masts or steel mast components or the like. Further But can also be placed on the transition elements, the nacelle or the steel mast.

The inventive method provides that the installation is carried out even in a one-man assembly with a small device. The arrangement and design of the biasing system also allows just as easy replacement of a defective tendon in case of need by a single person as their sorted disposal without the costly separation of building materials in the demolition of the tower at the end of its lifetime.

Carbon fiber components have long been used in the field of mobility to save weight. In the construction industry, they have been able to prevail little, because they are compared to the proven reinforced concrete construction on the one hand more expensive and on the other hand, no long-standing experience, as is the case with reinforced concrete. So far, carbon fibers in construction have been used almost exclusively in renovation cases, where factors such as the height of a rehabilitation layer decide to use the new building material for reinforcement purposes.

For prestressing tendons in prestressed concrete construction for bridge constructions and transmission masts, carbon fiber fins have also been tested in the recent past and generally classified as usable. However, the higher material costs compared to the tendons made of prestressing steels on the market are faced with a wide application.

Against the prejudice of the art, the invention proposes, despite the supposedly higher cost of using carbon fiber tendons for the construction of prestressed concrete shafts for wind turbines. The characteristics in detail:

The design of tendons in towers of wind turbines (WEA), which proposes the invention consist of low-weight carbon fiber fins with easily mounted tendon anchors, which are attached to designated abutments. There is no corrosion in carbon fiber tendons, which control and maintenance is significantly reduced. Preferably, the proposed tendons made of carbon fiber fins with specially provided anchoring systems externally or internally connected without a connection, that is, without casting in the guide or in the cavity, which is particularly in the case of externally composite version in one of the proposed embodiments, a very easy installation, a very easy replacement in case of damage over the entire operating period and a very easy disassembly allow. Not to mention that retightening in case of need can also be done easily. According to the abutment of the tendon anchors are designed so that both the assembly, as well as the disassembly of the abutment can be done very easily and the components are easy to install, easy to maintain and easy to disassemble.

According to the invention, the tendons are preferably equipped at their ends with tendon heads after the system collator (voltage-dependent wedge anchorage) or with the system LAP (alligator clip) and fixed in the abutments.

The abutments are preferably mounted flat on the concrete surface, which makes concreting the abutment just as superfluous as complicated formwork geometries for receiving the abutment especially in the clamping cellar of the tower structure of conventional biasing systems of towers of wind turbines. This is especially true when the abutment presses with a normal force on the concrete surface.

According to the invention, the carbon fiber tensioning lamellae are guided in several layers along the wall of the tower construction, spacer elements holding the individual lamellae of a tensioning element stack at a distance from one another and thus preventing the individual lamination from hitting each other and against the wall. The spacers are permanently fixed or shaped so that they can not slip out of the space. According to the invention can be provided in the shaft wall of the concrete tower recesses in which run along the tendons or along which they are guided along. According to the invention wrapping or holding elements may be provided which secure the tendons on the skirt wall and in this way prevent swinging, warping or hitting against the wall and each other. This is particularly advantageous because the lateral deflections and vibrations of a WEA tower compared to prestressed concrete bridges are many times greater, occur several orders of magnitude more often and the impact resistance of the slats is significantly lower, especially compared to prestressing steels, which over the operating period feared fatigue or degradation of the material by striking or against the wall beating.

According to the invention, the tendon is preferably prefabricated at one end provided with a tendon anchoring delivered to the site and with a free end on the other side. Preferably, the prefabricated end is installed at the lower end and the free end at the upper clamping point with the necessary tensile stress applied by a clamping press against the abutment or an abradable point and then attached. In this way, advantageously eliminates the clamping cell, or the clamping cellar can be dimensioned considerably smaller than previously was the case in particular for the equipment cost of prestressing presses for conventional tensioning strands. The foundation can be made flatter by this. The clamping presses used for carbon fiber laminations can be used, which require considerably less space than prestressing presses for prestressing steels. These clamping presses can also be used on the confined space of the transition piece at the upper end of the concrete shaft, which was previously not possible with the conventional clamping presses in the tightly packed tendons along the inner wall of the transition element, especially for vollüberdrückte designs.

The "free end" of the tendon does not necessarily consist of loose ends of carbon fiber fins or wires, it merely means that this end of the tendon is designed so that it can be tensioned and then fixed, while the other end is preferably formed so that you no longer have to process it with a clamping press, but This end is merely hung, looped in, screwed or otherwise secured.

The invention proposes that the tendons are mounted and secured in the tower foundation only on a designated abutment device, which preferably also mitvorspannt large parts of the tower foundation and in this way enables an improved force curve in the area of the tower base, the foundation and the tower foundation.

According to the invention allows this assembly that can be dispensed heavy equipment and large cranes for picking up and lifting tension strands of prestressing steel and their heavy tendon anchorages. Rather, the tendons can be retracted in case of need even with a simple motor winch from bottom to top in the tower. The tensioning presses for tendons made of carbon fiber, which are known from the building renovation, are lightweight, compact, easy to transport and can be used due to their very small footprint optionally at the upper or lower clamping point. You do not need lifting gear to move and transport.

In the case of externally compositeless embodiments with tendon anchors bolted directly to the abutment (and not performed), the entire tendon is only retained from the front, i. laterally, brought into position, fastened and prestressed. The design effort on all components necessary for this reduces considerably.

The tendons made of carbon fiber are called in particular bands, also lamellae.

The enveloping elements may also be paints, coatings or foams.

The tendons are held at least at one point of their free length, ie between their attachment ends, which tendon can be frictionally held by retaining elements or by abutment against the wall or against a wall-mounted contact element. The fasteners and the Spanngliedwiderlager the tendons can be designed so that the bands or wires of the tendon can be individually retracted and fixed.

Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. In the drawings show:

Figure 1 describes by way of example the prior art with respect to tendons in tower structures for wind turbines and sketchy indicated their installation tool, a clamping press. The tension strands 10 for overpressing the concrete shaft or the finished parts 08 are guided from above through an opening 12 in the steel flange of a transition element 14 and a possible tension channel 16 into the foundation 20 of the tower structure. There, the tendons are biased below a clamping channel 22 with a clamping press 24 against the abutment 28 and secured with clamping anchors 32 against the abutment.

For this step, a suitably trained, optionally available clamping cell 26 is provided.

Shown are two different versions of the prior art, right with a separate adapter piece of steel and left with a hybrid adapter piece of steel and reinforced concrete. The plan view 40 shows that the tendon heads 42 are very close at the top and no maneuvering surface for the attachment of conventional clamping presses for tendons of prestressing steel longer exists. 06 denotes further possible patch steel tubular elements on the concrete tower 04, provided that the transition element does not connect directly to the nacelle.

FIG. 2 shows the construction according to the invention with tendons of carbon fiber lamellae or wires 50. These are guided through the openings 52 provided on the steel flange of a transition piece 54, if necessary also by a partial or through the entire shaft reaching clamping channel 56th At the lower end of the tendons 50 are guided by a clamping channel 62 in the foundation 60 to the lower abutment 68, and there provided with an anchorage in the form of tendon heads 72.

The foundation 60 can be made much simpler and in particular flatter, due to the much smaller footprint of the clamping press 70.1, as in the prior art.

Optionally, the clamping press 70.2 can also be attached at the upper end in the region of the transition piece 54. The tendon head 72 also requires much less space in the region of the transition piece, as a principal plan view 80 shows, so that clamping presses can also easily find space there and can do their job.

Figure 3 shows the construction according to the invention with tendons made of carbon fiber fins or wires 50 using the example of a downwardly oriented transition piece 54 with a clamping channel section 56. In the embodiment, the wires or fins 50 are passed through openings 52 in the transition piece and then with an anchoring system with tendon heads 72.2 on clamped a compact carbon fiber tendon tensioning press 70.2. The step can be done analogously at the lower end of the tendon with a tendon head 72.1, which presses against the abutment 68, which is preferably only glued.

Figure 4 shows the construction according to the invention with tendons of carbon fiber fins or wires 50 using the example of a radially inwardly jumping transition piece 54 to which the clamping system with tendon heads 72.2 for the carbon fiber fins (or wires) can be easily attached. This advantageous embodiment eliminates openings, holes and clamping channels for the backfilling of steel flanges and the like. And allows easy attachment, such as tightening, the tendon heads 72.2, which can additionally push against an offset 54.2, which serves as an additional abutment to relieve the fittings. The working step can be carried out analogously also at the lower end of the tendon with a tendon head 70.1, which is attached to a reinforcing element 67 and in which the reinforcing element 67 also geometrically so may be formed such that the tendon head 72.2 is additionally mounted against an offset 67.1 of the reinforcing element.

This offset can also be used by the clamping press as an abutment. Through this embodiment, any iteration and passing through tendons through openings, holes, clamping channels, etc., which greatly simplifies the processing step of biasing concrete sections of wind turbines and the replacement of defective tendons on the one hand very simplistic and to which hardly any tools are necessary, since the Tendons in case of damage and on the day of demolition simply forward, ie laterally, can be taken away.

The tendons are thus only from the front, i. attached laterally against the shaft wall and from the front against the inside of the foundation or provided there recesses.

In addition, in this embodiment, both ends of the tendon can be prefabricated with tendon heads more. In this case, one end of the tendon is attached to the abutment and the other pulled by the pretensioning press behind the tendon head in its final position and then also attached to the abutment there. Shown in dashed lines in the isometric view is an additional security 69. FIG. 5 shows the invention in section through the tower shaft 04 and possible

(A) shows in grooves provided preferably glued blades 92. (b) shows a variant for internally composite carbon fiber wires 94, (c) shows an embodiment in which the carbon fiber fins with an adhesive 104 on (d) shows an embodiment in which the inner wall of the lateral surface of the concrete pipe holds recesses, see enlarged portion of Figure 5, in which the tendons 96 are guided along, (e) shows a variant in which the tendons 98 be attached to the inside of a smooth surface. The enlargements show schematically possible attachments by brackets, rings or other fasteners or enveloping elements. FIG. 6 shows, in two embodiments, possible spacers, that is to say separating elements 102 between the carbon fiber lamellae 100 for preventing clashing, abrading, wear and abrasion as a result of the vibrations of the lamellae with one another and the tensioning members against the wall of the tower shaft. Preferably, these spacers are continuously present over the entire free length of the carbon fiber fins. An analogue feed is also provided for wires.

The tendons may also be enclosed by Hüllelementen, which may be plastic coatings, plastic sheaths, or even paints, coatings or foams.

In general, the tendons will be at least at one point of their free length, i. held between their attachment ends, wherein the clamping member can be held by holding elements or by engagement with the wall or on a wall-mounted contact element over friction. If the inside of the tower shaft bulges inward at one point, the tendons will contact the wall of the tower shaft at this point and bear against it, in which case a considerable contact pressure is exerted. The resulting friction prevents the tendons from lateral displacement, i. held. Alternatively, between wall and tendons there may also be a contact part, e.g. Wall or tendon spares. Also fasteners such as clamps, clamps, guides can hold the tendons on the tower shaft against lateral displacement.

The tendons are brought without crane to the transition element on the tower shaft, in particular by means of a light winch.

Claims

claims

1 . Prestressed concrete tower structure for a wind turbine with a tower base, a tower shaft, a transition element (54) and a foundation (60), wherein the tendons (50) for applying the bias of carbon fiber, wherein at least three tendons (50) at least from the tower above of the foundation (60) extend at least to a transition element (54), wherein the tendons are fixed with tendon heads (72, 72.1 and 72.2).

2. tower construction according to claim 1, characterized in that the individual clamping lamellae or wires in the tendons by separating elements

(102) are separated from each other.

3. tower construction according to claim 1 or 2, characterized in that individual clamping lamellae or wires in the tendons of Hüllelementen, in particular paints, coatings or foams, are enclosed.

4. The method according to any one of the preceding claims, characterized in that the tendons run without passages and clamping channels.

5. The method according to any one of the preceding claims, characterized in that the clamping members are attached only from the front against the skirt wall and from the front against the inside of the foundation or provided there recesses.

6. tower construction according to one of the above claims, characterized in that the skirt wall is geometrically formed so that on its inside recesses are present, in which run through the tendons against lateral displacement.

7. tower construction according to one of the above claims, characterized in that a clamping cell is present in the foundation.

8. tower construction according to one of the above claims, characterized in that the tendons are formed as bands.

9. tower construction according to one of the above claims, characterized in that the tendons are formed as wires.

10. tower construction according to one of the above claims, characterized in that the transition element carries a tower crown on which the wind generator is mounted.

1 1. Tower structure according to one of the above claims, characterized in that the tendons are held at least at one point of their free length.

12. tower construction according to claim 1 1, characterized in that the tendons at least by a holding element or by contact with the

Wall or be held on a wall-mounted contact element.

13. A method for producing a tower structure according to one of the preceding claims, characterized in that the tendons are brought without crane to the transition element on the tower shaft, in particular by means of a winch.

14. A method for producing a tower structure according to one of claims 1 to 12, in particular according to the method of claim 13, characterized in that the tendons are pulled from below into the tower by a present at the tower end wind pulls the tendons upwards.

15. A method for producing a tower structure according to any one of claims 1 to 12, in particular according to the method of claim 13 or 14, the tendons are delivered prefabricated and mounted and secured only in the process of biasing in an abutment.

16. The method according to any one of the preceding claims, characterized in that the fastening elements of the tendons are formed so that the bands or wires of the tendon are individually retracted and fixed.

17. The method according to any one of the preceding claims, characterized in that for the installation of the tendons carbon fiber presses are used, preferably wherein the presses are also used at the upper clamping point.