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(11) | EP 4 390 002 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | CONCRETE ELEMENT, PROCESS FOR PRODUCING CONCRETE ELEMENT AND FORMWORK FOR CASTING CONCRETE ELEMENT |
| (57) The invention relates to a concrete element (10) delimited at least partially by
planar side surfaces (11), wherein the side surfaces (11) meet along edges (12), and
wherein the concrete element (10) comprises a metal frame (20) having edge profiles
(21) extending along the edges (12), which are fixed to each other and cast into the
concrete element (10). The invention also relates to process for producing a concrete element (10), wherein a formwork (100) is formed by: - providing a metal frame (20) with edge profiles (21) fixed to each other, and - releasably attached to the metal frame (20), from the outside of the metal frame (20), formwork elements (110) which together delimit a casting volume (200), then pouring castable concrete into the casting volume (200), thereby casting the metal frame (20) into the concrete, and after the concrete has set, removing the formwork elements (110) from the metal frame (20) and leaving the metal frame (20) in the concrete element (10). The invention also relates to a formwork (100) for casting a concrete element (10) according to the invention. |
[0001] The subject of the invention is a concrete element delimited at least partially by planar side surfaces, wherein the side surfaces meet along edges.
[0002] The invention also relates to a process for producing a concrete element. The invention further relates to a formwork for casting a concrete element.
[0003] Concrete elements are most often produced using casting forms or formwork. Conventional formwork consists of interlocking formwork elements, which can be made of wood, plastic or, preferably, for larger concrete elements, metal, which can withstand the higher pressures that occur during the casting of concrete. The metal formwork elements are usually joined by welding and/or bolting.
[0004] The formwork must be able to withstand with a small deformation the hydrostatic pressure created by castable concrete. For concrete elements used in radiation protection applications, there may be an additional requirement that the protective wall should allow disassembling and reassembling. In the case of such structures that can be disassembled and reassembled, it may also be necessary to protect the edges, among other things, so that small broken pieces of concrete and dust, which may also be activated or contaminated by radiation, do not arise during assembly and disassembly. In the prior art solutions the edge protection is usually made of steel sections (edge profiles) with L cross-section, which are arranged inside the formwork, in the corners of the formwork, during the pouring of the concrete. During the casting process, these steel sections are bonded into the concrete and become part of the concrete element. The main drawback of this method is that the dimensional accuracy of the resulting concrete elements will be determined by the dimensional accuracy of the formwork, i.e., how accurately the formwork elements are fitted together and how accurately they are sized. According to the state of the art, the dimensional accuracy achieved with standard formwork during the casting of prefabricated concrete elements of about a few meters size is approximately +/- 1 cm. In practice, however, it may often be necessary to produce concrete elements of a more precise size, for example for radiation protection walls, where the gaps between the concrete elements in the assembled structure must be less than 1 cm.
[0005] It was recognized by the inventors that the dimensional accuracy of the formwork produced by fixing the formwork elements together was not adequate for certain applications (e.g., the production of concrete elements for radiation protection).
[0006] The inventors have also recognized that edge profiles, which are also used for edge protection of concrete elements, could be used to create a metal frame with high dimensional accuracy by fixing the edge profiles together (e.g., by welding or bolting), with a dimensional error of no more than 1-2 mm even over several meters. It was also recognized that this metal frame could serve as a structural frame determining the size of the formwork, and that the formwork elements could be fixed to the metal frame instead of being fixed to each other. The dimensional accuracy of the formwork thus created is determined by the dimensional accuracy of the metal frame.
[0007] It is an object of the invention to provide a concrete element and a process for producing such a concrete element free from the disadvantages of prior art solutions. It is an object of the invention to provide a concrete element with a higher dimensional accuracy than hitherto possible and to provide a process for producing concrete elements with a higher dimensional accuracy than previously possible.
[0008] The invention also aims to create a formwork that can be used to produce concrete elements with high dimensional accuracy.
[0009] The problem according to the invention is solved by a concrete element delimited at least partially by planar side surfaces, wherein the side surfaces meet along edges, and which comprises a metal frame with edge profiles extending along the edges, which are fixed together and cast into the concrete element.
[0010] The problem is further solved by a process for producing a concrete element, comprising making a formwork by:
- providing a metal frame with edge profiles fixed to each other, and
- releasably attaching to the metal frame, from the outside of the metal frame, formwork elements which together delimit a casting volume,
[0011] The problem is further solved in accordance with the invention by a formwork comprising a metal frame having edge profiles fixed to each other and defining edges of the concrete element, and formwork elements releasably attached to the metal frame from the outside of the metal frame and together delimiting a casting volume.
[0012] According to the invention the concrete element is produced with a formwork in which the formwork elements are not fixed to each other, but to a metal frame made of edge profiles that are fixed to each other and define the edges of the concrete element, which becomes part of the concrete element when the casting is finished.
[0014] Further details of the invention are described by means of exemplary embodiments and drawings. In the drawing,
Figure 1a is a schematic perspective view of an exemplary embodiment of a concrete element according to the invention;
Figure 1b is a schematic perspective view of a further exemplary embodiment of a concrete element according to the invention;
Figure 1c is a schematic perspective view of a further possible embodiment of a concrete element according to the invention;
Figure 2a is a schematic A-A sectional view of the concrete element shown in Figure 1a;
Figure 2b is the schematic A-A sectional view of the concrete element shown in Figure 1b;
Figure 3 is a schematic perspective view of an exemplary embodiment of a metal frame according to the invention;
Figure 4 is a schematic perspective view of a possible embodiment of a formwork according to the invention containing the metal frame shown in Figure 3;
Figure 5 is a schematic top view of the formwork shown in Figure 4;
Figure 6a is a schematic view depicting a possible method of attaching the formwork elements to the metal frame according to the invention;
Figure 6b is a schematic view showing another possible method of attaching the formwork elements to the metal frame according to the invention;
Figure 7 is a schematic perspective view of an exemplary embodiment of a support structure according to the invention in its mounted state on the formwork.
[0015] Figure 1a shows a schematic perspective view of a possible embodiment of a concrete element 10 according to the invention. In the context of the present invention, the concrete element 10 is understood to be a concrete block produced by casting concrete, which is at least partially delimited by flat side surfaces 11 and which has edges 12 at the intersection of the side surfaces 11. Preferably, each of the side faces 11 of the concrete element 10 is planar, as can be seen, for example, in the embodiments illustrated in Figures 1a and 1b. However, the concrete element 10 may also include curved side faces 11 (for example, in the case of a cylindrical concrete element 10, the cylinder shell defines curved side faces 11). In this case, the edges 12 may also include curved portions.
[0016] Inside the concrete element 10, conventional reinforcing structures such as rebars (reinforcing rod or reinforcing bar) may be arranged, which may include iron bars, iron mesh, steel bars, steel mesh, etc., as known to the skilled person.
[0017] The concrete element 10 according to the invention comprises a metal frame 20 having edge profiles 21 extending along the edges 12, which are attached to each other and cast into the concrete element 10. The adjacent edge profiles 21 forming the metal frame 20 are directly attached to each other, for example by welding or bolting, i.e., the edge profiles 21 are not held together solely by the concrete of the concrete element 10. Thus, the metal frame 20 according to the invention forms a self-supporting structure by itself without the concrete of the concrete element 10, as shown, for example, in Figure 3. The edge profiles 21 are preferably straight metal sections having edges 21a. If the concrete element 10 also comprises curved side surfaces 11, then the corresponding edges 12 may also comprise curved sections, and accordingly the edge profiles 21 of the metal frame 20 may also be suitably curved.
[0018] In a possible embodiment, the edge profiles 21 may be formed, for example, as metal sections with an L-shaped cross-section, preferably made of steel, stainless steel or, for example, aluminum, i.e., L-profiles, as can be seen in Figures 6a and 6b. The edge profiles 21 are preferably joined together where the edges 12 meet, i.e., at the corners of the metal frame 20. This can be easily achieved, for example, by mitering the edge profiles 21 meeting at the corners and welding the mitered ends together, as will be apparent to the skilled person. In a particularly preferred embodiment, at least a portion of the edge profiles 21 of the metal frame 20 is provided with one or more projections 21' extending into the interior of the concrete element 10, two of which are shown in Figure 3 by way of example. The projections 21' can be formed, for example, as triangular tabs welded to the edge profiles 21, as can be seen in Figure 3. The projections 21' are bonded into the concrete of the concrete element 10 to enhance the connection between the concrete and the metal frame 20 and to prevent the edge profiles 21 from separating from the concrete under external forces, such as impact.
[0019] In the case of the concrete element 10 of the invention, the edge profiles 21 extend along the edges 12. This includes the case in which the edge profiles 21 are partially embedded in the concrete element 10 but are arranged on the outer surface of the concrete element 10 (see Figures 1a and 2a), and the case in which the edge profiles 21 are arranged parallel to the edges 12, inside the concrete element 10 (see Figures 1b and 2b).
[0020] In the embodiment of Figures 1a and 2a, at least a part of the edges 12 are formed by the metal frame 20. In a particularly preferred embodiment, all edges 12 of the concrete element 10 are formed by the metal frame 20 (see Figure 1a), but of course embodiments where certain edges 12 are not covered by the edge profile 21 are also conceivable where appropriate. The edge profiles 21 on the outer surface of the concrete element 10 act as edge protectors and the edges 12 coincide with the edges 21a of the edge profiles 21. In the embodiment shown in Figure 1a, the metal frame 20 is flush with the side surfaces 11, i.e., it does not protrude from the planes of the side surfaces 11. It is noted that the edge profiles 21 formed as L-profiles preferably extend parallel to the planes of the side surfaces 11, whereby a portion of the area of the side surfaces 11 is formed by the edge profiles 21, as can be seen in Figure 1a.
[0021] In a possible embodiment, the metal frame 20 comprises a metal plate forming at least one side surface 11 of the concrete element 10. This is particularly advantageous in the case of concrete elements 10 where it would be difficult to arrange formwork along some of the side surfaces 11 when casting the concrete. To overcome this problem, such side surfaces 11 are conveniently formed by a metal plate 13 as shown in Figure 1c, which also serves as a formwork element. The metal plate 13 may be formed integrally with one or more edge profiles 21 or may be connected thereto, for example by welding. Such metal sheets 13, after casting, remain within the concrete element 10, forming part thereof.
[0022] In the embodiment shown in Figures 1b and 2b, the edge profiles 21 are positioned inside the concrete element 10 such that the edges 12, 21a are parallel to each other. That is, the edges 12 run along the external side of the edges 21a, so that these edges 12 are indirectly defined by the edges 21a. It is noted that other embodiments can also be envisaged where edge profiles 21 are not arranged in the concrete block 10 along all edges 12.
[0023] The invention also relates to a formwork 100 for casting the concrete element 10, the formwork 100 comprising the metal frame 20 containing the edge profiles 21 fixed to each other which define the edges 12 of the concrete element 10, and formwork elements 110 releasably attached to the metal frame 20 from the outside of the metal frame 20 and together delimiting a casting volume 200. The casting volume 200 is not closed, for example it is open from above, in order to allow the castable concrete to be introduced into the casting volume 200. For example, the formwork elements 110 may preferably be metal plates, such as steel plates, which are fastened to the frame 20 by means of fastening elements 130, such as screws, from the outside, i.e., to the sides of the edge profiles 21 opposite to the casting volume 200. The formwork elements 110 are releasably secured to the frame 20 supporting them, that is, once the concrete has been poured and the concrete has set, the formwork elements 110 can be easily removed from the metal frame 20.
[0024] The shape of the formwork elements 110 is adapted to the shape of the side surfaces 11 to be created, preferably flat metal sheets for flat side surfaces 11, or suitably curved, molded metal or other rigid sheets for curved side surfaces 11.
[0025] In the embodiment shown in Figure 6a, the formwork elements 110 are fixed directly to the frame 20, i.e., contacting the edge profiles 21. As a result, the concrete poured into the casting volume 200 and set therein results in the concrete element 10 shown in Figures 1a and 2a, wherein at least part of the edges 12 are formed by the edges 21a of the frame 20, and wherein the side surfaces 11 and the portions of the edge profiles 21 forming the edges of the side surfaces 11 (e.g., the legs of the L-profile) lie in the same plane.
[0026] In the embodiment illustrated in Figure 6b, the formwork elements 110 are indirectly attached to the frame 20 by means of spacer elements 135 arranged between the edge profiles 21 and the formwork elements 110. The spacer element 135 may preferably be, for example, a piece of tubing. In order to ensure that the casting volume 200 is sealed at the lateral edges 12 and that the concrete does not leak there, the formwork elements 110 are fixed to the frame 20 at the edges 12 in contact with each other, as can be observed, for example, in Figure 6b. In this embodiment, the concrete setting in the formwork 100 results in the concrete element 10 shown in Figures 1b and 2b, wherein the edge profiles 21 are positioned inside the concrete element 10, parallel to the edges 12. In this case the 12 edges have no edge protection, and the 12 edges are formed by concrete.
[0027] In a preferred embodiment, the formwork 100 includes a support structure 300 arranged outside the casting volume 200 and attached to one or more formwork elements 110 to prevent deformation of the form work elements 110 during concrete casting. The elements of the support structure 300 are attached to the formwork elements 110 in a known manner, for example by means of bolts, and preferably also to the ground. Embodiments may also be possible where the support structure 300 is releasably attached to the metal frame 20 in addition to the formwork elements 110. In this way, the support structure 300 may also hinder possible deformation of the frame 20. In another possible embodiment, the formwork 100 comprises one or more connecting elements 400 arranged in addition to or instead of the support structure 300 within the casting volume 200 and fixed to the formwork elements 110. The one or more connecting elements 400 may be, for example, an anchor bolt or a threaded stem attached to the opposing formwork elements 110 (see Figure 5). The one or more connecting elements 400 internally stiffen the formwork 100 so that it can better withstand the hydrostatic pressure of the concrete poured into the casting volume 200.
[0028] The invention also relates to a process for casting the concrete element 10. During the process a formwork 100 is formed by:
- providing a metal frame 20 with edge profiles 21 fixed to each other, and
- releasably attaching to the metal frame 20, from the outside of the metal frame 20, formwork elements 110 which together delimit a casting volume 200.
[0029] The edge profiles 21 are preferably formed as metal sections with an L-shaped cross-section having edges 21a, i.e., L-profiles, and are preferably fixed to each other at the corners where the edges 21a meet, as can be seen in Figure 3. The fixing of the edge profiles 21 may be achieved, for example, by welding, as is known to the skilled person. It is noted that the stiffness and structural strength of the metal frame 20 may be further enhanced, where appropriate, by metal stiffeners (not shown in the figures) connecting and securing the edge profiles 21. The metal frame 20 is shaped according to the shape of the concrete element 10 to be created, with the edge profiles 21 extending along the future edges 12 of the concrete element 10.
[0030] After the metal frame 20 has been assembled, formwork elements 110 are attached to the outer sides of the metal frame 20, for example by means of fasteners 130 formed as bolts. Together, the formwork elements 110 define the casting volume 200 into which the castable concrete can be poured, i.e., the formwork elements 110 define the side surfaces 11 of the concrete element 10 to be created.
[0031] In the next step of the process, the castable concrete is poured into the casting volume 200, thereby casting the metal frame 20 into the concrete, and after the concrete has set, the formwork elements 110 are removed from the metal frame 20, and the metal frame 20 is left in the concrete element 10. If, for example, the formwork elements 110 are fixed directly to the frame 20, i.e. in contact with the edge profiles 21, as shown in Figure 6a, the concrete poured into the casting volume 200 and set there results in the concrete element 10 shown in Figures 1a and 2a, where the edges 21a of the frame 20 coincide with the edges 12 of the concrete element 10, and where the side surfaces 11 and the parts of the edge profiles 21 extending along the side surfaces 11 (e.g. legs of the L-profile) lie in the same plane. In other words, the edge profiles 21 are only partially embedded in the concrete element 10, and the edge profiles 21 are visible in the concrete element 10 (see Figure 2a). If, on the other hand, the formwork elements 110 are fixed to the frame 20 indirectly, for example by means of the spacer elements 135 described above, the concrete that sets in the formwork 100 results in the concrete element 10 shown in Figures 1b and 2b, where the edge profiles 21 also extending along the edges 12, but are inside the concrete element 10, so that they do not coincide with the edges 12, but parallel to them. In this case, the edge profiles 21 are not visible in the concrete element 10 (see Figure 2b).
[0032] In one possible embodiment, prior to casting, reinforcing bars, such as reinforcing mesh (not shown in the figures), are arranged in the casting volume 200 within the metal frame 20, as known to the skilled person.
[0033] When casting small concrete elements 10, the stiffness of the metal frame 20 may be sufficient to hold the formwork elements 110 in place. However, in the case of larger formwork 100 for larger concrete elements 10, prior to casting the castable concrete into the casting volume 200, one or more formwork elements 110 are supported from outside the casting volume 200 by means of a support structure 300 attached to one or more formwork elements 110 and/or the metal frame 20. In this way, the displacement and deformation of the formwork elements 110 under the pressure of the castable concrete is prevented. According to a possible embodiment the support structure 300 fixed to the metal frame 20 may also be used to correct the shape of the metal frame 20, either before casting or immediately after casting, but before the concrete has set.
[0034] In another possible embodiment, before the castable concrete is poured into the casting volume 200, at least two formwork elements 110 are fixed to each other by the connecting element 400 arranged in the casting volume 200, as can be observed for example in Figure 5. The connecting elements 400 passing through the casting volume 200 can be, for example, metal rods, for example anchor bolts, which are screwed to the formwork elements 110. The connecting elements 400 stiffen the formwork 100 from the inside by preventing the connected formwork elements 110 from moving away from each other due to the hydrostatic pressure of the castable concrete. The connecting elements 400 are preferably left in the concrete element 10 after casting and setting of the concrete, increasing its structural rigidity. If it is not wished to leave the connecting elements 400 in the concrete element 10, the connecting elements 400 can be arranged in plastic pipes, for example (not shown in the figures) and after the concrete solidifies and the formwork elements 110 have been removed, the connecting elements 400 can simply be pulled out of the pipes, i.e., only the plastic pipes remain in the concrete element 10.
1. A concrete element (10) delimited at least partially by planar side surfaces (11),
wherein the side surfaces (11) meet along edges (12), characterized in that the concrete element (10) comprises a metal frame (20) having edge profiles (21)
extending along the edges (12), which are fixed to each other and cast into the concrete
element (10).
2. The concrete element (10) according to claim 1, characterized in that at least a part of the edges (12) is formed by the metal frame (20).
3. The concrete element (10) according to claim 1 or 2, characterized in that the metal frame (20) comprises a metal plate (13) forming at least one side surface
(11) of the concrete element (10).
4. The concrete element (10) according to any one of claims 1 to 3, characterized in that all edges (12) of the concrete element (10) are formed by the metal frame (20).
5. The concrete element (10) according to any one of claims 1 to 4, characterized in that the edge profiles (21) are fixed to each other at the junctions of the edges (12).
6. The concrete element (10) according to any one of claims 1 to 5, characterized in that the edge profiles (21) are L-profiles.
7. A process for producing a concrete element (10), characterized by making a formwork (100) by:
- providing a metal frame (20) with edge profiles (21) fixed to each other, and
- releasably attaching to the metal frame (20), from the outside of the metal frame (20), formwork elements (110) which together delimit a casting volume (200), pouring castable concrete into the casting volume (200), thereby casting the metal frame (20) into the concrete, and after the concrete has set, removing the formwork elements (110) from the metal frame (20) and leaving the metal frame (20) in the concrete element (10).
8. The process according to claim 7, characterized in that, prior to casting the castable concrete into the casting volume (200), supporting
one or more formwork elements (110) from outside the casting volume (200) by means
of a support structure (300) fixed to the one or more formwork elements (110) and/or
to the metal frame (20).
9. The process according to claim 8, characterized by correcting the shape of the metal frame (20) by means of the support structure (300)
fixed to the metal frame (20).
10. The process according to any one of claims 7 to 9, characterized in that, prior to casting the castable concrete in the casting volume (200), fixing at least
two formwork elements (110) to each other by means of a connecting element (400),
preferably an anchor bolt, arranged in the casting volume (200) and fixed to the at
least two formwork elements (110).
11. A process according to any one of claims 7 to 10, characterized by providing rebar within the metal frame (20).
12. A formwork (100) for casting a concrete element (10) according to any one of claims
1 to 6, characterized in that it comprises a metal frame (20) having edge profiles (21) fixed to each other and
determining edges (12) of the concrete element (10), and formwork elements (110) releasably
attached to the metal frame (20) from the outside of the metal frame (20) and together
delimiting a casting volume (200).
13. The formwork (100) according to claim 12, characterized in that it comprises a support structure (300) arranged outside the casting volume (200)
and releasably attached to one or more formwork elements (110) and/or to the metal
frame (20).
14. The formwork (100) according to any one of claims 12 to 13, characterized in that it comprises a connecting element (400), preferably an anchor bolt, arranged in the
casting volume (200) and fixed to the formwork elements (110).
15. The formwork (100) according to any one of claims 12 to 14, characterized in that the formwork elements (110) are attached to the metal frame (20) via spacer elements
(135).