Concrete ceiling element with concrete web

Abstract

In a ceiling element (1) with two shells (2, 3) and with at least one intermediate element running between the shells (2, 3), which is connected to the two shells (2, 3) by means of lugs (5) in such a way as to transmit forces in such a way that it forms a statically activated component of the ceiling element (1), wherein the shells (2, 3) each consist of reinforced concrete, the invention proposes that the intermediate element be designed as a web (4) made of reinforced concrete.

Description

[0001] The invention relates to a ceiling element according to the preamble of claim 1.

[0002] From DE 20 2022 105 282 U1, a generic ceiling element is known which is designed as a hybrid prefabricated element and has a wooden element between the two concrete shells, which can be designed as a web or beam with a correspondingly small cross-section, or which can be designed as a slab with a correspondingly larger cross-section.

[0003] The invention is based on the object of further developing a generic ceiling element so that it can be particularly easily recycled after its service life. Furthermore, it is intended to enable high force transmission between elements in a simple manner while using as few resources as possible.

[0004] This object is achieved by a ceiling element according to claim 1. Advantageous embodiments are described in the subclaims.

[0005] In other words, the invention proposes that the web, which is statically activated to absorb shear forces and connects to the two concrete shells and gives the ceiling element a high flexural rigidity, be manufactured as a reinforced concrete component, just like the two concrete shells. In this way, both the shells and the one or more webs arranged in a ceiling element are always made of the same base material, namely concrete, so that later processing of the ceiling element is facilitated by the ceiling element containing as few different materials as possible. The web can be made of fiber-reinforced concrete, with fibers made of different materials being considered, such as plastic, carbon or steel fibers, and each can be in the form of random fibers or fiber mats. However, the web can also contain, either exclusively or in addition to the fibers, rod-shaped reinforcement elements, such asthe well-known reinforcing steel bars.

[0006] In one design, both the shells, the web and the cleats are made of reinforced concrete, so that the materials used for the various components are as identical as possible.

[0007] The design of the web as a reinforced concrete component is surprising, given that long concrete components with a comparatively small cross-section are susceptible to fracture. The webs are narrow and can be, for example, 10 or 12 m long. However, the invention is based on the idea that the webs are handled exclusively at the ceiling element manufacturing plant and thus under controlled conditions. During transport and handling on a construction site, the webs do not need to be handled individually, but rather form part of the entire ceiling element and are protected accordingly.

[0008] In addition, the fracture sensitivity of the web can be significantly reduced by reinforcing material, and since the two shells are designed as reinforced concrete components anyway, typically as reinforced concrete components, it does not adversely affect the reprocessing of the ceiling element if the webs are also made of reinforced concrete, for example if reinforced concrete components contain steel reinforcement material.

[0009] The cleats serve to transfer shear forces between a shell and the adjacent web in a slab element subject to deflection. Therefore, elements that can transfer the shear forces occurring in the longitudinal direction of the web, acting between the web and an adjacent shell, to this adjacent shell or from the shell to the web are suitable as cleats. Furthermore, the cleats advantageously serve to transfer tensile forces from a first shell via the web into the second shell.

[0010] In one embodiment, the lugs are made of concrete, i.e., a similar or even the same material as the reinforced concrete elements. In another embodiment, the lugs are made of a material other than concrete, for example, steel, so that the lugs are made of a similar or even the same material as the reinforcement if the reinforced concrete components are designed as reinforced concrete components.

[0011] The design of the cleats made of concrete, with or without reinforcement, is considered particularly advantageous because, on the one hand, it enables particularly good connection and force transmission with adjacent concrete components, and, on the other hand, this design is advantageous from a production point of view and thus particularly economical. Therefore, unless expressly stated otherwise, the typical design of the web is assumed to be concrete cleats.

[0012] If the cleats are designed as concrete components, excellent force transmission between the web and the shells is ensured, going beyond the purely mechanical interaction. Since in this case not only the cleats but also the web are made of concrete, the cleats can be designed as integral components of the web, which simplifies the manufacture of the slab element. The design of the reinforcement during web manufacture can influence whether the cleats are designed with or without reinforcement. A further simplification can be achieved by manufacturing the web in a standardized, always identical length, which allows for advantageous and therefore economical production in large quantities.Since the exact dimensions of the ceiling element and thus also the web length are individually determined by the respective dimensions of the structure to be erected, the webs must be cut to the individually required length anyway.

[0013] If the cleats are not made of concrete, they can also be designed as integral components of the web, for example in the form of so-called headed bolts, bars, (bar) loops, or the like, which protrude upwards and / or downwards from the web into the adjacent shell. For example, the headed bolts, bars, (bar) loops can be made of steel and be part of the web's reinforcement, although they protrude from the web in sections. Such cleats can be slanted, curved, or angled, e.g., U- or L-shaped, in order to be able to transfer not only the aforementioned shear forces, but also load-bearing or tensile forces between the web and the adjacent shell.

[0014] In an alternative design, the lugs connecting the web to the shells are formed not as integral, but rather as separate components of the web. This offers the possibility of individually determining the position and number of lugs to suit the respective static conditions and thus meeting the static requirements as economically as possible. In this case, too, the lugs can be made of concrete, steel, iron, or similar materials. Regardless of their material, the initially separate lugs can be glued, screwed, bolted, and / or similarly bonded to the web, thus permanently fixing them to the web to ensure the desired force transmission.

[0015] If the separate cleats are not made of concrete, they can be designed, for example, in the form of so-called washer screws, which are commercially available and therefore economical. In this case, the web can be manufactured in a closed mold, without any elements protruding beyond the mold. Instead, threaded sleeves can be cast into the web, so that after the web is completed, the aforementioned washer screws can be screwed into the threaded sleeves to form cleats that can absorb shear forces in the longitudinal direction of the web, as well as vertical load-bearing forces, and transfer them to the adjacent component.

[0016] In one embodiment, a number of lugs can be designed as headed bolts, each with at least one head section and one rod section, wherein a headed bolt is radially expanded in the head section.

[0017] Advantageously, the radial expansion in the head section can create a collar that engages behind a reinforcement arranged in a shell, allowing tensile forces from the shell to be transferred into the web. According to the invention, the bar can be round or polygonal. Furthermore, the radial expansion can be circumferential, resulting in an approximately T-shaped cross-section, or it can also be a partial radial expansion.

[0018] In this case, the term number can include one, several or all of the elements or objects mentioned.

[0019] The use of headed studs is advantageous because they are comparatively easy to produce and manufacture in large quantities. Such headed studs are typically created by forming, for example, by heating and compressing an end section of a reinforcing bar, creating a radial expansion in the head section. Forming a reinforcing steel can be particularly advantageous for creating a headed stud. Headed studs within the meaning of the present proposal preferably have a diameter of at least 6 mm in the bar section. In an advantageous embodiment, at least the head section protrudes vertically beyond the web.

[0020] The vertical projection of the head portion defines the depth of engagement of the headed stud into a shell. Initial tests have shown that the engagement depth is advantageously 40-80% of the shell thickness, preferably 50-60%, particularly preferably 60%. Taking these engagement depths into account, load transfer can be achieved particularly efficiently.

[0021] Preferably, a head bolt can have a head section at each end, thus two head sections, which each particularly preferably protrude in height beyond the web, so that a first head section of the head bolt engages in a first shell and a second head section of the same head bolt engages in a second shell.

[0022] In a further development, a number of lugs can be designed in a rod-shaped manner with a curved course at least in sections.

[0023] Advantageously, a metallic rod, such as a reinforcing bar or the like, can form a lug in the sense of the present proposal after being formed to create a curved profile. Such lugs are particularly simple to manufacture and can be easily adapted to the expected load situations, for example, by defining a specific bending radius and / or a required rod diameter.

[0024] Preferably, the curved path is essentially U-shaped, so that the bending radius is essentially 180°.

[0025] In one embodiment, the curved course and the web comprise an engagement opening which opens in the longitudinal direction of the web.

[0026] The aforementioned access opening can advantageously serve, in particular, to pass through rod-like reinforcement or the like, in order to create a statically activated, i.e., force-transmitting, connection between a shell and the web. For example, for an improved connection of a reinforcement to the cleat, it can be provided that the cleat and reinforcement are first bonded together using a wire or by means of a weld spot before the shell is cast, into which the cleat and reinforcement are at least partially embedded.

[0027] For a particularly advantageous further development, it can be provided that the curved course forms a loop such that sections of a cleat overlap and / or cross each other.

[0028] In the case of an overlapping design, the lug can, for example, be designed in the manner of two substantially U-shaped sections, wherein the free ends of the respective U-shaped sections are aligned with each other and partially overlap.

[0029] In an alternative embodiment, it can be provided that the cleat has only a substantially U-shaped section and one or both free ends are in turn formed, for example parallel to the plane of the U-shaped section and / or substantially orthogonal thereto.

[0030] In the case of a crossing design, the cleat can form a loop with an engagement opening, wherein this engagement opening is advantageously embedded at least in sections in the web, i.e. cast in concrete, so that the engagement opening is reduced in area by the web.

[0031] A lug with a curved profile, in particular in the manner of the loops presented and / or in the manner of the further embodiments presented with a curved profile, represents a particularly advantageous embodiment which, regardless of the features otherwise described herein, is based on a particularly inventive step.

[0032] In accordance with the present proposal, it can preferably be provided that different designs of a cleat can be provided for the same ceiling element. This allows situation-specific load cases to be taken into account and optimal load transfer within a particular structure to be achieved. Preferably, different cleats can be arranged in an alternating (irregular) manner within a web, whereby, in addition to the design of the cleat, its orientation can be varied alternatively or additionally.

[0033] Furthermore, it can be provided that the web of a proposed ceiling element is not designed as a single piece, i.e., a continuous one, but instead as a split web. A split web is particularly advantageous from a production-technical perspective, as fixed lengths for webs can be prefabricated and any incomplete web lengths can be replaced or supplemented using separate web sections. Likewise, split webs or any incomplete web lengths can be used to provide installation space within a ceiling element for a pipe and / or cable line or the like.

[0034] In one embodiment, a lug has a number of projections which are aligned so as to extend substantially parallel to a shell. Likewise, alternatively or additionally, it can be provided that projections are aligned substantially in the direction of a shell. An arrangement of projections serves, among other things, to be able to counteract tensile and / or shear forces acting in particular on the shell and webs. Preferably, the projections can be designed in the manner of a (partial) thread which extends, for example, along the rod section of a headed bolt or along a rod-shaped lug with a curved section. Alternatively or additionally, particle-like projections can be provided which increase the surface roughness and thus help to counteract relative movement between the shell and web. The above-described projections orIn this case, a surface roughening can be provided for a cleat and / or for the web.

[0035] In one embodiment, the lugs protrude laterally beyond the web, allowing them to transmit load-bearing forces directed transversely to the surface of the ceiling element or a shell, particularly uplifting tensile forces. For this purpose, the lugs can, for example, have an approximately T-shaped cross-section, so that they are held in the respective shell with a positive fit with respect to the load-bearing forces.

[0036] In one embodiment, the lugs protrude above the web in height so that they form thrust cams which can transfer thrust forces acting in the longitudinal direction of the web between the adjacent shell and the web.

[0037] In one embodiment, the lugs have transverse bores, i.e., bores that run perpendicular to the longitudinal direction of the web. Support struts extend through these transverse bores. These struts can be made of steel, for example, the same material as the reinforcing steel used. The support struts each extend laterally beyond the web and the lugs and each run within a shell. Therefore, similar to the aforementioned lugs that extend laterally beyond the web, they can transfer tensile forces between this shell and the web.

[0038] In a design considered advantageous, the support struts extend beyond the web and the lugs on both sides to ensure symmetrical load distribution. This extension on both sides allows for a large overall load-bearing length of the support struts while simultaneously keeping the lever arms relative to the lug as short as possible.

[0039] In one embodiment, the lugs are arranged offset from one another at the top and bottom of the web, namely towards the upper and lower, respectively adjacent shell of the ceiling element, in order to achieve the most even distribution possible of the forces acting on the web via the lugs.

[0040] The ceiling element according to the invention can be manufactured by first producing the web from reinforced concrete. If the lugs are provided as separate components, they are connected to the web. A shell made of reinforced concrete, for example the so-called upper shell, is cast lying flat with its future upper side facing downwards. The web is pressed into the not yet set, deformable concrete. The lugs and, if used, the supporting struts are encased in the concrete of the shell and ensure a positive connection between the web and the shell. A second shell made of reinforced concrete is also cast lying flat as the lower shell after the first, upper shell has set.This first, upper shell is lifted together with the web as a jointly manageable assembly, turned by 180° so that the web is located below the upper shell, and then this assembly is pressed into the not yet set, deformable concrete of the lower shell, so that here too the connection between the shell and the web is made when the concrete of the lower shell sets.

[0041] The ceiling element is designed to maintain a specific position during use, thus having a defined top and bottom surface and, accordingly, an upper and lower shell. In one embodiment, the ceiling element has a tensioning element in its lower half, i.e., in its lower shell, or in the lower area of ​​the web, or in the transition area between the web and the lower shell. The tensioning element is designed to generate compressive stress within the ceiling element. This counteracts downward deflection of the ceiling element.

[0042] In one embodiment of the ceiling element, the aforementioned tensioning element is prestressed, namely stretched. The tensioning element can be designed, for example, as a rod, a strand, or the like. In this prestressed state, it is cast in the concrete of the web and / or the lower shell during manufacture of the ceiling element, so that in the finished ceiling element, the concrete is in direct contact with the tensioning element. When the tensioning element is relieved of load after the concrete has set, it tends to contract. Due to the skin friction between the tensioning element and the concrete, the tensioning forces are transferred to the concrete via the skin friction, so that compressive forces act inside the concrete in the lower half of the ceiling element.

[0043] In an alternative embodiment, the tensioning element does not have direct contact with the concrete, but is instead arranged in a sheathing tube. Tensioning devices are arranged on the tensioning element and rest against the web and / or the lower shell. The tensioning element can be designed as a rod, in particular as a threaded rod, or also as a stranded wire, whereby in the area where the tensioning devices are located, the tensioning element can each have a section designed as a threaded rod. The tensioning devices can have contact plates that rest against the concrete, as well as a clamping nut that runs on the threaded rod on the side of the respective contact plate facing away from the concrete. The length of the sheathing tube is so short that it has no contact with the two contact plates.After the concrete has set, the tensioning devices are activated by screwing the nuts on the threaded rods against the support plates so that compressive forces are introduced into the concrete in the lower half of the ceiling element via the support plates.

[0044] Depending on the dimensions of the ceiling element, several webs are typically used to connect the upper and lower shells.

[0045] Embodiments of the invention are explained in more detail below using purely schematic representations. Fig. 1a perspective, partial view of a first embodiment of a ceiling element, Fig. 2a plan view of the web of the ceiling element of Fig. 1 , Fig. 3 a top view of the section of Fig. 1 , Fig. 4a vertical section through the section of the Fig. 3 along the line IV - IV, Fig. 5 - 8Views of a second embodiment similar to the Fig. 1 bis 4 , Fig. 9 a vertical section of a further embodiment of a ceiling element with headed bolts, Fig. 10 a vertical section of a further embodiment, and Figs. 11a-c views of different brackets.

[0046] In Fig. 1 A section of a ceiling element 1 is shown. The ceiling element 1 has an upper shell 2 and a lower shell 3, each made of reinforced concrete, which are connected to each other by a web 4 made of reinforced concrete running between them, which in the illustrated embodiment is also made of reinforced concrete. The designations "upper shell 2" and "lower shell 3" refer not only to the arrangement in the drawings, but also to the subsequent position that the ceiling element 1 will assume during use.

[0047] In Fig. 1 Hidden edges of the individual components are shown in dashed lines. It can therefore be seen that the web 4 forms a plurality of lugs 5 as integral components of the web 4 on its upper side, towards the upper shell 2, and also forms lugs 5 on its underside, towards the lower shell 3. The lower lugs 5 are arranged offset from the upper lugs 5 in the longitudinal direction of the web 4. Although the lugs 5 can be designed from the same material as integral components of the web 4, which is also the case in the illustrated embodiment, a linguistic distinction is made between the web 4 and the lugs 5, since the lugs 5 can also be manufactured as separate components, unlike the illustrated embodiment, and possibly, likewise unlike the illustrated embodiment, can be made of a material other than concrete.

[0048] Fig. 2 shows the bridge 4 of Fig. 1 as a single component from above. The lugs 5 are wider than the web 4, so that the upper lugs 5 conceal the web 4. Between two adjacent upper lugs 5, the web 4 can be seen, and below it the overhang with which the lower lugs 5 protrude laterally beyond the web 4. In the longitudinal direction of the web 4, the gaps between the adjacent lugs 5 on the upper side are just as large as the lugs on the underside, and vice versa, so that in the top view, the upper and lower lugs do not overlap, but alternate.

[0049] Fig. 3 shows the section of Fig. 1 of the ceiling element 1 in a plan view. Hidden edges are drawn visibly here, so that the web 4 offers the same view as in Fig. 2 and the lower shell 3 is covered by the upper shell 2.

[0050] Fig. 4 shows a cross-section of the situation of Fig. 3 along line IV - IV in Fig. 3 The lugs 5 project not only laterally beyond the web 4, but also vertically, so that they can transmit shear forces acting as thrust cams in the longitudinal direction of the web 4. This creates an almost castle-battlement-like contour of the web 4 on both the upper and lower sides. Due to the offset arrangement of the upper and lower lugs 5, the section runs through an upper lug 5, while from the adjacent lower lug 5 in Fig. 4 the front view can be seen.

[0051] Fig. 5 shows a perspective view of a section of a second embodiment of a ceiling element 1. This embodiment corresponds in its basic features to the embodiment of the Fig. 1 bis 4 The upper and lower lugs 5, which are also formed from the same material on the web 4 in this embodiment, project upwards and downwards above the web 4, as in the first embodiment. However, the lugs 5 do not project laterally beyond the web width, which is evident from the Fig. 6 und 7 becomes clear and simplifies the production of web 4.

[0052] Instead, some of the lugs 5 are provided with through holes which run as transverse holes 6 transverse to the longitudinal direction of the web 4.

[0053] The Fig. 7 und 8 make it clear that support struts 7 are inserted into the cross holes 6. Fig. 8 It can be seen that the transverse bores 6 are arranged at such a height in the lugs 5 that the support struts 7 guided therein lie in the shells 2 and 3 and are completely surrounded by the material of the respective shell 2, 3, so that they can transmit shear and load-bearing forces.

[0054] Fig. 9 shows a vertical section of another embodiment of a ceiling element 1. It is essential that the cleat 5 is designed as a headed bolt 8, each with a head section 9 at its end and a rod section 10 connecting the head sections 9, wherein the headed bolt 8 is radially expanded in the head sections 9. The radial extensions form a collar 11, which engages behind support struts 7 in the upper and lower shells 2, 3. Thread-like projections 12 on the rod section 10 counteract tensile forces that occur, particularly under load.

[0055] Fig. 10 shows a vertical section of another embodiment of a ceiling element 1 with a bracket 5, which is rod-shaped with at least partially curved profile 13 and, in particular, is essentially U-shaped on two sides. The curved profile 13 and the web 4 comprise an engagement opening 14, which opens in the longitudinal direction of the web 4. First support struts 7a extend through the engagement opening 14 and increase the shear and tensile strength of the composite of the ceiling element 1. Second support struts 7b are aligned orthogonally to the first support struts 7a and connected to them.

[0056] The Fig. 11a-c show views of different cleats 5. In Fig. 11a a bracket with a curved profile 13 is shown, with further angled free ends 15. In particular, the bending radius of the curved profile 13, as well as the alignment of the free ends 15 can be designed specifically for the load case in order to achieve an optimal load introduction into the ceiling element 1. In Fig. 11b und 11c Rod-shaped lugs are shown with at least partially curved profile 13, wherein the curved profile 13 forms a loop in each case. In Fig. 11b the loop is designed in such a way that sections of the lug 5 overlap each other and, in contrast, Fig. 11c Sections that cross each other. Reference symbol:

[0057] 1 Ceiling element 2 Upper shell 3 Lower shell 4 Web 5 Cleat 6 Cross hole 7 Support strut 7a First support strut 7b Second support strut 8 Head bolt 9 Head section 10 Bar section 11 Collar 12 Projection 13 Curved section 14 Access opening 15 Free end

Claims

1. Ceiling element (1) comprising two shells (2, 3) and at least one intermediate element extending between the shells (2, 3), which is connected to the two shells (2, 3) by means of lugs (5) in a force-transmitting manner in such a way that it forms a statically activated component of the ceiling element (1), wherein the shells (2, 3) each consist of a reinforced concrete, characterized by that the intermediate element is designed as a web (4) made of reinforced concrete.

2. Ceiling element according to claim 1, characterized by that the lugs (5) are formed as integral components of the web (4).

3. Ceiling element according to claim 1, characterized by that the lugs (5) are designed as separate components and are in particular glued and / or bolted to the web (4).

4. Ceiling element according to one of the preceding claims, characterized by thata number of lugs (5) are designed as head bolts (8) each having at least one head section (9) and one rod section (10), wherein a head bolt (8) is radially expanded in the head section (9).

5. Ceiling element according to claim 4, characterized by that at least the head section (9) protrudes in height above the web (4).

6. Ceiling element according to one of the preceding claims, characterized by that a number of lugs (5) are designed in a rod-shaped manner with a curved course (13) at least in sections.

7. Ceiling element according to claim 6, characterized by that the curved course (13) is essentially U-shaped.

8. Ceiling element according to claim 6 or 7, characterized by that the curved course (13) and the web (4) comprise an engagement opening (14) which opens in the longitudinal direction of the web (4).

9. Ceiling element according to one of claims 6 to 8, characterized by thatthe curved course (13) forms a loop such that sections of a lug (5) overlap and / or cross each other.

10. Ceiling element according to one of the preceding claims, characterized by that a lug (5) has a number of projections (12) which are aligned to extend substantially parallel to a shell (2, 3).

11. Ceiling element according to one of the preceding claims, characterized by that the lugs (5) are made of reinforced concrete.

12. Ceiling element according to claim 11, characterized by that the shells (2, 3), the web (4) and the lugs (5) are made of reinforced concrete.

13. Ceiling element according to one of the preceding claims, characterized by that the lugs (5) protrude laterally beyond the web (4).

14. Ceiling element according to one of the preceding claims, characterized by thatthe lugs (5) protrude in height above the web (4) in such a way that they form thrust cams.

15. Ceiling element according to one of the preceding claims, characterized by that the lugs (5) have transverse bores (6) through which support struts (7) extend, each of which projects laterally beyond the web (4) and beyond the lugs (5).

16. Ceiling element according to one of the preceding claims, characterized by that the lugs (5) at the top and bottom of the web (4) are arranged offset from one another relative to the adjacent shell (2, 3).

17. Ceiling element according to one of the preceding claims, characterized by that one of the two shells (2, 3) forms the lower shell (3) in use and the ceiling element (1) has a tensioning element in its lower half which generates a compressive stress within the ceiling element (1).

18. Ceiling element according to claim 17, characterized by thatthe tensioning element is cast in a prestressed state by the concrete of the web (4) and / or the lower shell (3) in such a way that after the tensioning element is relieved, the tensioning forces are transferred to the concrete via the skin friction.

19. Ceiling element according to claim 17, characterized by that the tensioning element is arranged in a sheathing tube, and that tensioning means are arranged on the tensioning element, which rest against the web (4) and / or the lower shell (3) in such a way that, after the concrete has set, compressive forces can be introduced into the lower half of the ceiling element (1) by actuating the tensioning means.

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