Procedure for demolishing a pylon

Abstract

The invention relates to a method for demolishing a pylon, the pylon having a base body (10) as a reinforced concrete structure, which is provided with a tension cable reinforcement arrangement (20) comprising one or more tension cables (21n), comprising the following method steps: a) producing a drop jaw (30) by destroying the reinforced concrete structure in a wedge-shaped drop jaw zone (13) of the base body (10), Dividing the pylon into an upper section (11) and a lower section (12) by means of the drop jaw (30), Creating a hinge zone (14) by means of the drop jaw (30), which hingedly connects the upper section and the lower section at the level of the drop jaw (30) by means of at least one tensioning cable (21n), b) performing a gravity-induced or gravity-assisted downward pivoting movement of the upper section (11), wherein the upper section (11) performs a rotational movement around the hinge zone (14) and converts potential energy into kinetic energy c) Lateral impact of the upper section (11) positioned overhead after the downward pivoting movement on the lower section (12) and performing deformation work on the lower section (12) and upper section (11) by means of the kinetic energy of the upper section (11)

Description

[0001] The invention relates to a method for demolishing a pylon constructed as a reinforced concrete structure with tension cable reinforcement, in particular such a pylon of a wind turbine.

[0002] Various methods for demolishing tower-like structures are known from the state of the art. Particular problems arise when dismantling wind turbine pylons.

[0003] Explosive charges are often placed particularly on load-bearing sections of the building structure. The detonation of the explosive charges weakens the structure in the affected load-bearing sections to such an extent that the structure collapses. A particular disadvantage of such methods is the complex safety precautions required due to the specific hazards involved.

[0004] To limit the spatial area affected by a collapsing structure, attempts can be made to destroy the structure in small pieces using a particularly large number of explosive charges. Disadvantages include the complex preparation required due to the large number of blast holes that must be distributed across the entire structure, as well as the contamination and pollution of the surrounding area caused by stray debris. Furthermore, this is particularly difficult in the case of wind turbine pylons, as these structures are designed to be particularly stable due to the high dynamic loads they must absorb.

[0005] For this reason, it is also known to destroy only a wedge-shaped section in the base area of the pylons of such wind turbines, causing them to topple sideways along their entire length. Such wind turbines are usually located in agricultural areas. A fall bed is prepared in the zone of impact with the ground. For this purpose, the topsoil must be laboriously removed and stored, and earth for the fall bed must be added. Due to the increased spread of debris in the longitudinal axis of the fall direction, considerable length allowances are also required when constructing the fall bed. After the debris has been removed, the fall bed must also be laboriously dismantled and the area with the temporarily stored topsoil must be re-established. Another disadvantage is the soil compaction that remains down to deeper soil layers as a result of the pylon impact.

[0006] Another possible method is to demolish the structure in small pieces starting from the top and without using explosives. However, this is very time-consuming and costly and is particularly difficult given the existing high construction heights of such pylons.

[0007] The object of the invention is therefore to provide a time-saving, cost-effective and environmentally friendly demolition method for pylons, which is particularly suitable for pylons of wind turbines, while avoiding the disadvantages of the prior art.

[0008] The problem is solved by the features listed in patent claim 1. Preferred developments arise from the subclaims.

[0009] The method according to the invention for demolishing a pylon is based in particular on the fact that wind turbine pylons, which are constructed as reinforced concrete structures, commonly have tension cable reinforcement. A solution has surprisingly been found that, by exploiting this structural property, enables a particularly advantageous method for demolishing a pylon, hereinafter also referred to as the demolition method.

[0010] The demolition method according to the invention thus relates to a pylon having a base body as a reinforced concrete structure provided with a tension cable reinforcement arrangement. The tension cable reinforcement comprises one or more tension cables.

[0011] The base body is typically constructed from a multitude of reinforced concrete ring segments arranged one above the other, with diameters tapering towards the top. The reinforced concrete ring segments have tubular channels arranged along their longitudinal axis in their shell. The tubular channels are aligned in the assembled position and form continuous channels from the base to the top, into each of which a tensioning cable is inserted. The tensioning cables are coupled to a counterbearing at one end and tensioned at the other end with elastic elongation. This significantly improves the buckling strength of the pylons, enabling them to absorb permanent dynamic loads.

[0012] The demolition method according to the invention comprises the following process steps. a) Creating a drop jaw by destroying the reinforced concrete structure in a wedge-shaped drop jaw zone of the base body, Dividing the pylon into an upper section and a lower section using the drop jaw, Creating a hinge zone by means of the drop jaw, which connects the upper section and the lower section at the level of the drop jaw by means of at least one tensioning cable. b) performing a gravity-induced or gravity-assisted downward pivoting movement of the upper section, whereby the upper section performs a rotational movement around the hinge zone and converts potential energy into kinetic energy. c) Lateral impact of the upper section positioned overhead after the downward pivoting movement on the lower section and performing deformation work on the lower section and upper section by means of the kinetic energy of the upper section

[0013] In process step a), a drop jaw is created by directly destroying the reinforced concrete structure in a wedge-shaped zone.

[0014] The wedge-shaped zone can be described as a section formed by two oppositely angled and intersecting cutting planes across the main body. This zone is physically part of the main body and is referred to herein as the wedge-shaped drop zone. The wedge tip defines a drop zone center plane that is substantially orthogonal to the main longitudinal axis of the pylon. The drop zone center plane preferably intersects the main longitudinal axis at a height above ground that corresponds to at least half the total height of the pylon and more preferably between 55% and 65% of the total height.

[0015] The local destruction of the reinforced concrete structure can preferably be achieved by explosives introduced into previously drilled holes. A work platform can be advantageously used for this purpose, which is raised to the desired working height by a crane. The crane can use a load-bearing crane platform that is usually reserved for maintenance work on the wind turbine. The spatial clearance created as a result of the destruction of the reinforced concrete structure of the wedge-shaped drop zone is hereinafter referred to as the drop zone.

[0016] By installing the drop jaw, the pylon is divided into an upper section and a lower section at the drop jaw zone center plane. The upper section and lower section meet at a hinge zone, which provides a hinged connection. The hinge zone is the remaining section of the reinforced concrete structure that was not removed by demolition during the creation of the drop jaw. The hinge zone center plane lies essentially in the same plane as the drop jaw center plane. The hinge zone therefore represents a weakened zone.

[0017] According to the invention, at least one of the tensioning cables remains in the hinge zone, thus providing the articulation and thereby ensuring the downward pivoting movement around this axis of rotation in the subsequent work step.

[0018] In process step b), the gravity-induced or gravity-assisted downward pivoting movement of the upper section occurs. Gravity-induced means that after the drop jaw is created, the upper section tilts sideways due to gravity alone, thus initiating the downward pivoting movement. Gravity-assisted means that the downward pivoting movement is initiated by an additional force input, for example, via a pull rope, and then continues automatically due to gravity.

[0019] During the downward pivoting movement, the upper section and the lower section remain connected in the hinge zone via at least one tensioning cable, so that this forms an axis of rotation of a rotational movement of the upper section.

[0020] During the downward pivoting movement, the potential energy of the previously vertical upper section is converted into kinetic energy. This process continues until the upper section is positioned overhead, with the former upper end of the pylon pointing downward.

[0021] In process step c), the upper section, positioned overhead after the downward pivoting movement, laterally impacts the lower section. Immediately before impact, the upper section and lower section are thus arranged essentially parallel to each other. The arrangement of the hinge center plane at at least half the total height of the pylon, and particularly preferably between 55% and 65% of the total height, ensures that the upper end of the upper section does not touch the ground at the end of the downward pivoting movement and is therefore not decelerated.

[0022] The impact causes deformation work to be performed on both the lower and upper sections simultaneously, using the kinetic energy of the upper section. In both collision partners, the forces during the impact act radially on the respective tubular structure, thus leading to its destruction along the entire length of both collision partners.

[0023] The method according to the invention has in particular the following advantages.

[0024] A solution was found that advantageously utilizes the special design of reinforced concrete pylons with tensioning cables, thus saving any additional resources.

[0025] Advantageously, virtually the entire potential energy of the upper section of the demolition structure is utilized to perform deformation work. This eliminates the need to apply the energy otherwise required for the fragmented destruction of the structure by other means, such as explosives or demolition tools. Furthermore, the potential energy is converted in a manner that does not harm the surrounding environment. In particular, a surprisingly simple and reliable way was found to avoid the soil compaction that would otherwise occur with state-of-the-art technology: by simultaneously utilizing the upper section and the lower section as mutual counterbearings for the force input for the deformation work.

[0026] Furthermore, the spatial area affected by demolition is significantly reduced. In particular, it is advantageous that complex measures such as the construction of a fall bed can be eliminated.

[0027] According to an advantageous development, the method for demolishing a pylon is characterized in that, in method step a), the reinforced concrete structure in the wedge-shaped drop jaw zone is destroyed using an explosive to create the drop jaw. The explosive is designed as a blasting agent or a pyrotechnic agent. In contrast to an explosive, a pyrotechnic agent is understood to be an explosive whose initial expansion velocity V0 is less than 1,000 m / s. An explosive with an initial expansion velocity V0 of 1,000 m / s or more is understood to be an explosive.

[0028] The construction of the drop jaw using explosives can be advantageously prepared by drilling blast holes. This allows a work platform to be set up, for example, with minimal equipment expenditure and using the regularly available crane area. The blast holes initially weaken the reinforced concrete structure only slightly, allowing safe work. The explosive is detonated in a conventional manner from a safe distance.

[0029] The advantage of this advanced version is that, compared to an explosive, the use of pyrotechnics requires significantly fewer formal and safety regulations. Furthermore, the scattering of pyrotechnics, and thus the contamination and danger to the surrounding area, is significantly reduced.

[0030] According to a next advantageous development, the method for demolishing a pylon is characterized in that a method step b0) is carried out as follows, b0) Arranging a pull rope on the upper section and triggering the downward pivoting movement by pulling on the pull rope on the drop jaw side.

[0031] This further development makes it possible to dimension the drop jaw in such a way that the pylon is only weakened to such an extent that the upper section does not immediately begin to pivot downwards without further measures. Only when a tensile force is applied to the pull rope will the reinforced concrete structure also fail in the hinge zone. This further development advantageously enables the use of non-explosive techniques such as a demolition robot with hammer tools for the local destruction of the reinforced concrete structure in the wedge-shaped drop jaw zone, as these tools can be removed from the danger zone after the work has been carried out. Only then, by pulling on the pull rope, is the downward pivoting movement and thus the further destruction of the pylon initiated.

[0032] According to an advantageous further development, the method for demolishing a pylon is characterized in that a method step a0) is carried out as follows, a0) Cutting one or more tensioning cables and leaving at least one tensioning cable in the hinge zone.

[0033] Advantageously, this refinement allows the potential axis of rotation of the upper section in the hinge zone to be precisely adjusted for the downward pivoting movement and, in particular, prevents lateral deflection of the downward pivoting movement. This ensures that the upper section impacts the lower section laterally over its entire length in method step c). In particular, for example, tensioning cables that run through the wedge-shaped drop jaw zone can be cut. Furthermore, the tensioning cables that are arranged opposite one another in the hinge zone near the wedge tip of the wedge-shaped drop jaw zone can be left in place, and the other tensioning cables in the hinge zone can be cut. This promotes structural failure after the creation of the drop jaw in the hinge zone, and the tensioning cables arranged opposite one another around the circumference provide a defined axis of rotation near the wedge tip of the drop jaw.

[0034] According to a further advantageous development, the method for demolishing a pylon is characterized in that a method step a1) is carried out as follows, a1) Destruction of the reinforced concrete structure in a tension side zone opposite the wedge-shaped drop zone at the level of the hinge zone.

[0035] In this refinement of the process, the reinforced concrete structure is further pre-weakened on the tensile side formed by the drop jaw. The tensile side zone is located opposite the drop jaw. Thus, the hinge zone, now consisting of two sections, is bounded on one side by the drop jaw and on the opposite side by the damage area in the tensile side zone.

[0036] Particularly advantageously, the tensioning cables running in the tension side zone are simultaneously cut. This creates a defined hinge line that provides a rotation axis for the subsequent downward pivoting movement. Furthermore, initiating the downward pivoting movement is facilitated. The order of the optional process steps a0) and a1) as well as process step a) is arbitrary. However, all process steps a), a0) and a1) mentioned precede process step b).

[0037] The invention is illustrated by way of example with reference to Fig. 1 Side view of a pylon before the start of the procedure Fig. 2 Sectional view of a pylon before the start of the procedure (enlarged) Fig. 3 Side view of a pylon with hinge zone weakening Fig. 4 Sectional view of a pylon with hinge zone weakening (enlarged) Fig. 5 Side view at the beginning of process step b) Fig. 6 Side view during process step b) Fig. 7 Side view at the beginning of process step c) explained in more detail.

[0038] Identical reference symbols in the various figures refer to identical features or components. These reference symbols are used in the description even if they are not shown in the respective figure.

[0039] Fig. Figure 1 shows an exemplary embodiment of the pylon to be demolished, at a height of approximately 90 m and a diameter of approximately 3 m at the upper end, with its base body 10 and the tension cable reinforcement arrangement 20, which is concealed within the reinforced concrete shell and is therefore shown in dashed lines. The tension cable reinforcement arrangement comprises several tension cables 21n.

[0040] The wedge-shaped drop jaw zone 13 shows the area where the drop jaw 30 is inserted during the demolition process. The drop jaw zone 13 is located in its central plane at approximately 60% of the total height of the pylon. The upper section 11 is located above the drop jaw zone 13, and the lower section 12 is located below. At the same height, the drop jaw zone 13 defines the hinge zone 14. The drop jaw zone central plane is also the hinge zone central plane. This plane is shown as a dash-dot line and, in the present example, is at a height of approximately 50 m.

[0041] Fig. 2 shows the inner tensioning cables 21n in an enlarged section through the drop jaw zone and hinge zone center plane, whereby for reasons of clarity only one of the tensioning cables 21n is provided with a reference line. Fig. 2 shows that the reinforced concrete structure remaining during the later creation of the drop jaw 30 with some tensioning cables 21n in the hinge zone 14 weakens the statics of the base body so considerably that failure of the remaining structure in the hinge zone 14 will occur due to the effect of gravity alone.

[0042] Fig. 3 and Fig. 4 essentially correspond to the Fig. 1 and Fig. 2 with the addition that in this embodiment the zone of weakening of the reinforced concrete structure is additionally shown in the tension side zone 15. As in particular the sectional view in Fig. As shown in Figure 4, in this embodiment, the hinge zone 14 is now formed in two sections. The dashed line shows the approximate course of the axis of rotation generated by the hinge zone 14 for the subsequent downward pivoting movement.

[0043] Fig. Figure 5 shows the state at the beginning of process step b), where a pull rope 40 is additionally attached to the upper section 11, and the downward pivoting movement is initiated by pulling on the pull rope as process step b0). The hinge zone begins to tear open, with the remaining tensioning ropes ensuring that the upper section does not detach and cannot slip over the drop jaw 30. The pylon is in Fig. 3 shown in simplified form without the prestressing cable reinforcement arrangement 20.

[0044] Fig. Figure 6 shows the pylon during process step b). The upper section 11 approaches an inclination of 90 degrees under sustained acceleration in the downward pivoting movement, which is represented by the curved arrow. Here, the tensioning cables 21n secure the hinge zone 14 - for simplification, Fig. 4 only one tensioning cable 21n is shown - the flexibility of this section and its function as a rotation axis and prevent the upper section 11 from slipping.

[0045] Fig. Figure 7 shows the pylon in process step c). The upper section 11 strikes the lower section 12 in an overhead position, causing the desired small-scale destruction of both collision partners 11 and 12. The immediate impact zone is schematically represented by the hatched area. After completion, the upper section 11 and the lower section 12 are largely fragmented, so that the remaining small-scale debris can be picked up and removed using excavators and possibly demolition tongs. Reference symbols used 10 basic bodies 11 Upper Section 12 Subsection 13 Drop mouth zone 14 Hinge zone 15 Train side zone 20 Spannseilbewehrungsanordnung 21n Spanner 30 Fallmaul 40 Pull rope

Claims

[1] Procedure for demolishing a pylon wherein the pylon has a base body (10) as a reinforced concrete structure, which is provided with a tension cable reinforcement arrangement (20) comprising one or more tension cables (21n), comprising the following process steps, a) producing a drop jaw (30) by destroying the reinforced concrete structure in a wedge-shaped drop jaw zone (13) of the base body (10), Dividing the pylon into an upper section (11) and a lower section (12) by means of the drop jaw (30), Creating a hinge zone (14) by means of the drop jaw (30), which hingedly connects the upper section and the lower section at the level of the drop jaw (30) by means of at least one tensioning cable (21n), b) performing a gravity-induced or gravity-assisted downward pivoting movement of the upper section (11), wherein the upper section (11) performs a rotational movement around the hinge zone (14) and converts potential energy into kinetic energy c) Lateral impact of the upper section (11) positioned overhead after the downward pivoting movement on the lower section (12) and performing deformation work on the lower section (12) and upper section (11) by means of the kinetic energy of the upper section (11) [2] Method for demolishing a pylon according to claim 1, characterized by that in method step a) the destruction of the reinforced concrete structure in the wedge-shaped drop jaw zone (13) for producing the drop jaw (30) is carried out by means of an explosive, wherein the explosive is designed as an explosive or as a pyrotechnic agent. [3] Method for demolishing a pylon according to one of the preceding claims, characterized by that a process step b0), which precedes process step b), is carried out as follows, b0) Arranging a pulling rope (40) on the upper section (11) and triggering the downward pivoting movement by pulling on the pulling rope (40) on the jaw side. [4] Method for demolishing a pylon according to one of the preceding claims, characterized by that a process step a0) is carried out as follows, a0) Cutting one or more tensioning cables (21n) and leaving at least one tensioning cable (21n) in the hinge zone (14). [5] Method for demolishing a pylon according to one of the preceding claims, characterized by that a process step a1) is carried out as follows, a1) Destruction of the reinforced concrete structure in a tension side zone (15) opposite the wedge-shaped drop zone (13) at the level of the hinge zone (14).

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