EP2734689A1

EP2734689A1 - Tower-shaped supporting structure

Info

Publication number: EP2734689A1
Application number: EP12728275.4A
Authority: EP
Inventors: Rolf J. WERNER
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-07-18
Filing date: 2012-06-18
Publication date: 2014-05-28
Also published as: DE102011079314A1; CN103732842A; WO2013010738A1; US20140150359A1; BR112014001152A2

Abstract

The invention describes a tower-shaped supporting structure (1), at least portions of which are hollow, with a plurality of interconnected prestressed concrete elements (2, 4), each of the prestressed elements (2) having a plurality of elongate prestressing means (10), more particularly wires or stranded cables, the majority of which are guided into an adjacent prestressed concrete element (4) and anchored there under tensile stress, characterised in that the prestressing means (10) have at least at one end a form-fitting means and the prestressing means (10) in the adjacent prestressed element (4) are anchored via at least one end anchoring element (12), which is connected to the prestressing means (10) via the form-fitting means.

Description

Tower-shaped structure

Technical area

The invention relates to a tower-shaped, at least

partially hollow structure with a plurality of interconnected prestressed concrete elements, wherein the

Prestressed concrete elements each having a plurality of elongate clamping means, of which the plurality are guided in an adjacent prestressed concrete element and there under

Tension is anchored.

State of the art

Tower-shaped structures of the type mentioned are used in particular in wind turbines widely used. The individual clamping elements are usually prefabricated, transported to the site and connected there or clamped together.

For example, EP 2 253 782 A1 discloses

generic tower-shaped structure in which the

Clamping the respective clamping elements out into an adjacent prestressed concrete element and there under tension

anchored. For this purpose, the

Prestressed concrete elements Through openings into which the clamping means are introduced. Subsequently, the free ends of the clamping means are anchored so that the individual prestressed concrete elements are braced together.

In addition to the suitability of the reaction vessel, the

To optimize thermal kinetics, the flexible walls 48 have a low thermal mass to provide a fast

To allow heat transfer. Fig. 3 shows a plan view of a reaction vessel 50 in direct contact with Heating elements 52 is and is surrounded by a cooling chamber 54. The thickness of each flexible wall is preferably between approximately 0.0001 to 0.020 inches, more preferably 0.0005 to 0.005 inches, and most preferably 0.001 to 0.003 inches. To achieve this small thickness, the wall may be a film, a sheet or a shaped, machined extruded or cast piece or other suitable thin and thin sheet

be flexible structure.

The material constituting the wall may be a polyalcohol such as polypropylene, polyethylene, polyester and other polymers, layered structures or homogeneous polymers, metals or

Metal sheet structures or other materials that are thin, flexible and adaptable and high

Allow heat transfer and preferably in the form of a film or sheet. If the scope of the

A vessel that holds the walls, is made of a particular material, such. Polypropylene, the walls are made

preferably of the same materials, e.g.

Polypropylene so that the thermal expansion and cooling rates of the walls are the same as those of the frame. Therefore, excessive stresses caused by heating or cooling in the materials are minimized, so that the

Sleeve walls the same

As anchoring means usually come so-called

Wedge anchors are used in which the free ends of the clamping means are clamped by wedges and thus anchored. However, these have the disadvantage that they are slippery. This causes the preload forces in the

Clamping means are relatively difficult to adjust, especially since first a comparatively large overvoltage must be applied in order to compensate for the slip occurring subsequently. Furthermore, a wedge anchoring requires a relatively large overhang of the respective clamping means. This means that the respective clamping means after the clamping process manually or with complicated tools must be disconnected. This is very laborious and sometimes dangerous and hinders the rest

Construction work on the structure.

It must be remembered that hundreds of such clamping devices are used on buildings of the type in question. Overall, thus far the usual wedge anchorage requires a high manual use and is hardly automated.

Presentation of the invention

It is therefore an object of the invention to provide a tower-shaped supporting structure of the type mentioned, which allows a precise and reliable clamping of the individual prestressed concrete elements together and an increased degree of automation in the manufacture of the tower-like structure.

This object is achieved by a tower-shaped supporting structure according to claim 1 and a method for producing a tower-shaped supporting structure according to claim 13.

Particularly preferred embodiments of the invention are specified in the dependent claims.

The invention is based on the idea to eliminate the slippage in the region of the end anchorage when connecting or clamping the individual prestressed concrete elements. For this purpose, the invention provides that at a

generic tower-shaped structure, the clamping means

Form-fitting means, in particular have a thread at least at one end, and the clamping means are anchored in the adjacent prestressed concrete element via at least one Endverankerungselement which is connected via the positive locking means or thread with the clamping means. In this way it becomes possible the respective ones

To connect prestressed concrete elements virtually slip-free with each other and thus the forces and deformations occurring during clamping extremely precise and reliable

adjust. In addition, thanks to the design of the clamping means can be minimized with a positive locking means, in particular thread at least at the respective free end of the supernatant of this free end, as this free end

can be gripped positively by a suitable clamping device. Thanks to the short protrusion is after the

Do not require disconnecting the respective free end required, which the workload and the

Operational safety considerably increased.

Another important advantage of the invention

Embodiment is that the distortion of the adjacent prestressed concrete elements significantly stronger

automate than in the prior art. While known wedge anchors require multiple interventions, the anchoring type of the invention can be almost

completely by a suitable clamping machine

carry out. Considering that these works often at a tower-shaped structure at very high altitude

must be carried out, allows the increased

Degree of automation more important benefits, such as

in particular, an improved work safety for construction site personnel. Last but not least, the

inventive connection and anchoring with

Realize components that have a simple construction and are therefore available at low cost.

According to one embodiment of the invention it is provided that the Endverankerungselemente are accessible from the cavity in the interior of the tower-like structure. This not only results in a simplified construction process, but the

Final anchorages of the structure are also available

Weather conditions effectively protected, so that the Durability of the structure increased or decreased

Requirements for the corrosion protection of the components can be made.

Although it is possible in principle that the

End anchoring elements support directly on the respective concrete of the prestressed concrete elements, is according to a

Development of the invention provided that the

Support end anchoring elements in each case via a support element in the concrete, which is preferably concreted into the concrete. This results in a uniform introduction of high local forces in the concrete, which reduces stress peaks in the concrete and beyond creep and

Shrinking deformations reduced. In addition, the required Querzug- or split reinforcement may be reduced if necessary. Furthermore, the support element can a

Contribute to, Issues in the respective

To avoid clamping devices. In this case, the support element can be configured in various ways, with a dome-like shape being particularly advantageous

has proved.

According to a development of the invention is further

provided that the clamping means optionally at least

are anchored in some areas via a composite in the insertion channels. This results in a special

uniform introduction of anchoring and clamping forces. At the same time, the clamping devices are protected against environmental influences and in particular corrosion. In addition, the anchoring means may optionally be unscrewed and reused after curing of the composite mass, resulting in the extremely high number of clamping and

Anchoring means is not negligible.

On the other hand, the optionally also possible use of clamping devices without composite has the advantage that a

Disassembly of the structure is facilitated. When pressing the insertion channels in a composite mass, it is of crucial importance that the insertion channels are completely filled with the composite material in order to achieve the desired anchoring and protective effect. Against this background, according to a development of

Invention provided that the Endverankerungselernente having a through hole (for example, a slot) for the escape of composite material. In this way, the composite mass can be pressed in from the lower end of the insertion channels, and that until composite material from the

Through openings exits the provided at the upper end of the insertion end anchoring elements. The

Through opening in the Endverankerungselementen thus has a double function, namely on the one hand to facilitate the full filling, and on the other hand one

Control mechanism for complete filling

provided.

On the other hand, it may be advantageous in the context of the invention to work selectively at specific locations without bond between clamping means and prestressed concrete elements. Against this background, it is provided according to a development of the invention that the bond between the clamping means and the prestressed concrete elements at least adjacent to a

Connecting joint between prestressed concrete elements is weakened or canceled. As a result, the free stretch length of the respective clamping means can be significantly increased, so that significantly larger clamping forces can be applied without jeopardizing the concrete of the respective prestressed concrete elements. In addition, by the deliberate abandonment of the

Composite ("debounding") and adjust the clamping force distribution to the respective concrete cross section, for example in

Areas where the concrete section of the

Prestressed concrete elements is increased or decreased.

According to a development of the invention is further

provided that the prestressed concrete elements insertion channels for Introducing clamping devices of adjacent prestressed concrete elements. The present invention thus does not work with "external bias", but preferably aims at the clamping means being passed through the respective prestressed concrete elements. This allows a uniform distribution of the clamping forces in a relatively small number of clamping devices. It is particularly preferred that the cross section of the insertion opposite to the

Insertion direction of the clamping means increases. As a result, the introduction of the clamping means in the insertion channels is much easier. In this case, the insertion channels can be produced, for example, by means of suitable die rods.

Alternatively, however, sheaths or the like can be provided, which is to achieve a good

Offer composite corrugated ducts.

The prestressed concrete elements may in principle have any basic shape in the context of the present invention.

According to a development of the invention, it is provided that the prestressed concrete elements are annular (for example as

rotationally symmetrical body such as cylinders, cones or

Paraboloid) are formed. This results in a particularly advantageous structural behavior and a simpler

Manufacturing process . Alternatively, according to a development of the invention, it is provided that the prestressed concrete elements

are formed ring segment-shaped. This results in a facilitated transport of prestressed concrete elements, and the

Prestressed concrete elements can be lying in a classic

Concrete bed to be concreted. This not only simplifies the production process, but also allows smooth contact surfaces on the later upper and lower sides of the prestressed concrete elements.

Furthermore, according to a development of the invention

provided that the clamping means in the respective

Prestressed concrete element are arranged in at least two layers. This makes it possible, with comparatively thin To work clamping devices, which in turn significantly simplifies the threading of the clamping means in the adjacent prestressed concrete elements and the tightening and anchoring of the clamping means. Furthermore, results in a particularly uniform

Tension distribution within the structure. Under

Clamping means layers are to be understood, which are parallel to the outer peripheral wall of the respective

Prestressed concrete element extend.

In the context of the present invention, in principle, the entire tower-like structure can essentially consist of

Consist of prestressed concrete elements. Likewise, the

However, the present invention also contemplates hybrid structures in which, for example, a lower portion of the tower-shaped structure is composed of prestressed concrete elements while an upper portion of the tower-shaped structure is formed by one or more sections of steel. Against this background, according to a development of

Invention provided that at least one prestressed concrete element with an adjacent tower section of steel such

connected is that the majority of elongated

Clamping in the adjacent tower section made of steel and anchored there under tension. Thus, the same basic principle of the connection is used, so that in principle the advantages described above can be achieved. Of particular importance, however, comes in this connection to a debounding of the clamping means, since in a connection with a tower section made of steel usually short tensioning or stretching paths are available, which can be extended by a targeted debounding in the corresponding prestressed concrete element, so without damaging the concrete high Tension forces can be applied. In addition, when connecting tower sections made of steel often even higher clamping forces are required than in a

Connection between prestressed concrete elements. In order to enable these high connection forces reliably, it is provided according to a development of the invention that additional anchoring means are provided which

anchored positively in the prestressed concrete element, guided to the adjacent tower section of steel and anchored there under tension. It comes thus a combination of clamping means on the one hand, at the same time for a

Provide bias of the respective prestressed concrete components, and anchoring means on the other hand, which are anchored only form-fitting manner in the prestressed concrete element used.

This makes it possible to achieve a targeted gradation of the clamping and anchoring forces with reliable connection of the components.

According to a development of the invention is further

provided that the adjacent tower section made of steel has a concrete section, in particular concrete ring, through which the elongated clamping means and optionally

An anchoring means are passed. By the

additional concrete section can be reduced surface pressure on the joint and at the same time increase the rigidity of the tower section made of steel. Furthermore, in particular in the case of a concrete ring, as a result of the transverse forces of the concrete ring caused by the tension forces, a suppression of the concrete surrounded by steel, which is the result

Introduction of very high loads allows. It is particularly preferred that the concrete section also

is positively connected to the steel of the adjacent tower section, so that there is a very stiff, sleek and reliable overall connection.

An inventive method for producing a

Tower-shaped structure is defined in claim 13. This allows, as already stated above, a highly automatable mode of operation and a low-slip and thus reliable connection between the respective

Prestressed concrete elements or tower sections. That's it particularly preferred that the prestressed concrete elements are concreted standing and are preferably made of self-compacting concrete.

However, in standing concreting, the problem may arise that the top surface of the prestressed concrete elements is uneven, since the top surface is flattened due to the protruding

Clamping is difficult to impossible. Before this

Background is provided according to a development of the invention that the prestressed concrete elements after concreting on its upper side with a self-leveling

Balance mass be provided. This results in a precise flat surface of the prestressed concrete elements, so that they can be stacked on the construction site without reliable reworking or compensation measures.

Brief description of the drawings

Fig. 1 shows schematically a partial sectional view of an embodiment of the tower-shaped supporting structure according to the invention;

Fig. 2 shows schematically the standing production of a

Prestressed concrete element for a tower-shaped supporting structure according to the invention;

Fig. 3 shows schematically a detail view of Fig. 2;

Fig. 4 shows schematically a compound of a

Prestressed concrete element with a steel tower section;

Fig. 5 shows schematically a further connection of a

Prestressed concrete element with a steel tower section.

Detailed description of preferred embodiments Preferred embodiments of the invention will now be described in detail with reference to the accompanying drawings.

A partial sectional view of a tower-like structure 1 according to the present invention is schematically illustrated in FIG. The tower-shaped supporting structure can serve in the context of the present invention for a variety of purposes,

for example, as a supporting structure for a wind turbine. The tower-shaped supporting structure 1 is constructed by stacking and clamping together a plurality of prestressed concrete elements 2, 4, the prestressed concrete elements 2, 4 each having a multiplicity of elongate tensioning means 10 in the form of tensioning wires or tensioning strands. As best seen in Fig. 1, are the clamping means 10 of the

Prestressed concrete element 2 at the top (right in Fig. 1) on this and are in the adjacent

Prestressed concrete element 4 out and anchored there under tension. In this case, all or only a majority of the respective clamping means may be anchored in the adjacent prestressed concrete element 4.

The clamping means 10 each have at their anchoring end a positive locking means, which in the present

Embodiment designed as a thread, for example, can also be performed in the manner of a ribbing, and the clamping means 10 are anchored in the adjacent prestressed concrete element 4 each have an end anchoring element 12, which is designed in the present embodiment as a clamping nut. This clamping nut is screwed onto the thread of the clamping means 10. However, it is also possible to use end anchoring elements which are pressed onto the positive locking means.

The bonding and bracing of the prestressed concrete elements 2 and 4 takes place, for example, as follows. The

Prestressed concrete element 2 is initially in a vertical position positioned so that the free ends of the clamping means 10 are vertically upwards and the region of the joint 32 is aligned horizontally. Subsequently, the

adjacent prestressed concrete element 4 by crane on the

Prestressed concrete element 2 placed on the clamping means 10 of the prestressed concrete element 2 are inserted into through holes within the adjacent prestressed concrete element 4 until finally the adjacent prestressed concrete element 4 is seated in the region of the joint 32 on the prestressed concrete element 2. In this state, the threaded, free ends of the clamping means 10 are slightly out of the through holes of the adjacent prestressed concrete element 4. Now, the Endverankerungselemente 12 on the clamping means 10th

screwed on, and the free ends of the clamping means 10 are gripped by a suitable clamping device, such as a hydraulic press. The thread of the clamping means 10 allows that only a very short

Projection of the clamping means 10 is required to grip them reliably by the clamping device.

Subsequently, the tensioning device applies a defined tensile stress to the tensioning means 10. After reaching the defined tension, the anchoring elements 12 and clamping nuts 12 are tightened so that they to the

Abut support elements 14. In this way, the bias state generated by the tensioner becomes

"Frozen". Now, the elasticity of the

Clamping device can be drained, with the

Anchoring elements 12 clearance ensures the maintenance of the bias state between the prestressed concrete elements 2 and 4.

Although this clamping operation can be performed by various separate devices, it is advantageously possible in the context of the invention, the steps described largely by an automated clamping and

Make screwing. The end anchoring elements 12 are accessible from a cavity 1 '(bottom in Fig. 1) in the interior of the tower-like structure 1, wherein the tower-shaped supporting structure, for example, as a hollow tower with a circular or other

Cross-section is executed.

The end anchoring elements 12 or clamping nuts are each supported by a supporting element 14 in the concrete, which is concreted in the present embodiment. The

Support member 14 may have different shapes, but is preferably formed in the manner of a dome or "bell", which ensures a uniform load transfer in the concrete.

In addition, the tensioning means 10 in the area between the joint 32 and the end anchoring elements 12 are optionally anchored in the prestressed concrete element 4 via a composite mass 16 (for example a composite mortar). This compound compound, for example, by subsequent compression in the corresponding cavities in the prestressed concrete element 4th

The end anchoring elements 12 preferably have a through hole (e.g., slot) for the escape of composite 16, for ease of compression and to ensure complete compression. In addition to a uniform anchoring, this composite compound also ensures reliable corrosion protection, alternatively or additionally other corrosion protection measures can be taken, such as greasing, coating, etc. Furthermore, the end anchoring elements 12 can be provided with a suitable cover to further improve the corrosion protection.

In contrast, in the region shown by "a" in FIG. 1, the bond between the clamping means 10 and the

Prestressed concrete element 2 adjacent to the connecting joint 30th weakened or even canceled ("debounding"). As a result, the stretching of the clamping means can be extended and thus avoid damage to the concrete when tightening the clamping means 10.

As can be seen in Fig. 1, the clamping means 10 are arranged in the present embodiment in two layers in the respective prestressed concrete element 2, 4. As a result, high clamping forces can be applied in the tower-shaped supporting structure 1, with the tower-shaped supporting structure 1 being able to be designed in the region of the end anchoring of the clamping means 10, as shown in FIG. 1, each with an enlarged cross section. In order to ensure a centered biasing force even in these areas, one or more clamping means 10 can be "debounded" as needed.

A possible method for producing the prestressed concrete elements 2, 4 is shown schematically in FIG. In this

Method are the prestressed concrete elements 2, 4 standing

concreted, usually in first a

large-format, for example cylindrical outer and

Built inside formwork and beyond suitable

Flange plates 40 are provided, between which the

Clamping means 10 are clamped. Subsequently, the

Formwork with suitable concrete, preferably

self-compacting concrete filled. Once the concrete has reached a sufficient strength, the clamping means 10 can be released from the flange plates 40, so that the

Clamping force is introduced into the prestressed concrete elements 2.

Furthermore, the support elements 14 are already set in concrete in this phase. The cross section of the

Through openings 20 preferably down to.

Furthermore, a self-leveling leveling compound 8 can be provided on the top of the prestressed concrete elements 2, 4 after concreting. This balancing mass is extreme

thin and therefore self-leveling, so without additional measures also in the field of protruding from the concrete clamping means 10 an exactly horizontal

Surface yields. This allows a precise

Facing the respective prestressed concrete elements 2, 4.

The detail I shown in FIG. 2 is shown enlarged in FIG. Fig. 3 shows that when manufacturing the

Prestressed concrete elements 2 through holes 20 are provided, in the later the tensioning means 10 can be introduced. These passage openings 20 can be provided for example by cladding tubes, but also by suitable die rods, wherein the die rods can be pulled after a first solidification de concrete to form the through holes 20. In order to be able to align the die bars (not shown) cleanly, auxiliary tubes 20 'can be provided (see Fig. 3).

The connection of a prestressed concrete element 2 with a

adjacent tower cutout made of steel, is shown in Fig. 4th

schematically shown in a partial sectional view. This compound operates on the same basic principle as a connection between two prestressed concrete elements, namely in which the clamping means 10 of the prestressed concrete element 2 is guided in the adjacent tower section 6 made of steel and anchored there under tension. To be sufficient

Dehnweg allow for the clamping of the clamping means 10, the clamping means 10 are in this embodiment in the region of the joint 34 over the "a" marked length "debounded", wherein the length a can be up to 1 m and more. Furthermore, additional anchoring means 30 are provided in this embodiment, which positively anchored in the prestressed concrete element 2, to the adjacent

Tower section 6 made of steel and there are also anchored under tension. Also these additional

Anchoring means 30 are debounded in the upper area. They can be formed by threaded rods with clamping nuts or the like. A further embodiment of a connection between a prestressed concrete element 2 and an adjacent steel tower section 6 is shown schematically in FIG. This corresponds to the basic principle of that shown in Fig. 4

Embodiment. However, in FIG. 5, the adjacent steel tower cutout 6 has a concrete section 6 ',

in particular concrete ring, through which the clamping means 10 and optionally anchoring means are passed. For manufacturing reasons, the mold section 6 is rotated by 180 °, aligned vertically and the concrete ring, preferably made of self-compacting concrete, concreting from above onto the steel ring. In addition, a

self-leveling leveling compound 8 applied, which automatically ensures the parallelism between the flange of the tower section 6 and stone surface of the concrete ring 6 '. In this case, the concrete ring 6 '(under the welded steel ring) is also form-fitting with the steel of the tower section 6

connected, for example by head bolts (right in Fig. 5) or by a corrugated or fluted inner surface of the tower section 6 (left in Fig. 5). This results in a particularly rigid connection of the adjacent

Tower sections and a high durability.

Claims

1. Tower-shaped, at least partially hollow support structure (1) having a plurality of interconnected

Prestressed concrete elements (2, 4), wherein the prestressed concrete elements (2) each having a plurality of elongated tensioning means (10), in particular wires or strands, of which the majority in an adjacent prestressed concrete element (4) out and anchored there under tension, characterized in that the tensioning means (10) are at least at one end

Have positive locking means, in particular a thread, and the clamping means (10) in the adjacent

Prestressed concrete element (4) over at least one

End anchoring element (12) are anchored, which is connected via the positive locking means with the clamping means (10).

2. Tower-shaped supporting structure according to claim 1, characterized

in that the end anchoring elements (12) are accessible from a cavity (1 ') in the interior of the tower-shaped supporting structure (1).

3. Tower-shaped supporting structure according to claim 1 or 2, characterized in that the Endverankerungselemente (12) each support via a support element (14) in the concrete, which is preferably concreted into the concrete.

4. Tower-shaped structure according to one of the preceding

Claims, characterized in that the clamping means (10) are optionally additionally anchored in the prestressed concrete element (4) at least in regions via a composite mass (16).

5. Turtnförmiges structure according to claim 4, characterized

in that the end anchoring elements (12) have a passage opening for the escape of

Compound (16) have.

6. Tower-shaped structure according to one of the preceding

Claims, characterized in that the composite between the clamping means (10) and the

Prestressed concrete elements (2, 4) at least adjacent to a joint between prestressed concrete elements (2, 4) is weakened or canceled.

7. Tower-shaped structure according to one of the preceding

Claims, characterized in that the

Prestressed concrete elements (2, 4) insertion channels (20) for

Inserting clamping devices (10) adjacent

Have prestressed concrete elements (2, 4), wherein preferably the cross section of the insertion channels (20) opposite to

Insertion direction of the clamping means (10) increases.

8. Tower-shaped structure according to one of the preceding

Claims, characterized in that the

Prestressed concrete elements (2, 4) annular or

are formed ring segment-shaped.

9. Tower-shaped structure according to one of the preceding

Claims, characterized in that the clamping means (10) in the respective prestressed concrete element (2, 4) are arranged in at least two layers.

10. Tower-shaped structure according to one of the preceding

Claims, characterized in that at least one prestressed concrete element (2) with an adjacent

Tower section (6) made of steel is connected such that the plurality of elongated clamping means (10) in the adjacent tower section (6) made of steel and anchored there under tension.

11. Tower-shaped supporting structure according to claim 10, characterized

characterized in that additional anchoring means (30) are provided, which form-fit in the

Prestressed concrete element (2) anchored, led to the adjacent tower section (6) made of steel and there under

Tension are anchored.

12. Tower-shaped supporting structure according to claim 10 or 11, characterized in that the adjacent tower section (6) made of steel, a concrete section (6 '), in particular

Concrete ring through which the elongated

Clamping means (10) and possibly anchoring means (30) are passed and preferably also

positively connected to the steel of the tower section (6).

13. A method for producing a tower-shaped supporting structure (1) according to one of the preceding claims, with the steps:

Producing prestressed concrete elements (2, 4), each having a plurality of elongated tensioning means (10), in particular wires or strands,

Connecting a prestressed concrete element (2) with a

adjacent prestressed concrete element (4) such that the majority of the tensioning means (10) of the prestressed concrete element (2) are guided into the adjacent prestressed concrete element (4),

Tensioning in the adjacent prestressed concrete element (4) guided tensioning means (10), and Tightening the anchoring elements (12) such that the tensioning means (10) are anchored under tension in the adjacent prestressed concrete element (4).

14. The method according to claim 13, characterized in that the prestressed concrete elements (2, 4) are concreted standing and preferably made of self-compacting concrete.

15. The method according to claim 14, characterized in that the prestressed concrete elements (2, 4) after concreting on its upper side with a self-leveling

Balance mass (8) are provided.