Semi-finished ceiling element as a prefabricated, transportable and installable ceiling element for the production of a composite ceiling by applying cast-in-place concrete to form a cast-in-place concrete layer

Abstract

Semi-finished ceiling element (1) as a prefabricated, transportable and installable ceiling element for the production of a composite ceiling (2) by applying cast-in-place concrete to form a cast-in-place concrete layer (40), wherein the semi-finished ceiling element (1) has a wooden panel support element (10) with a bottom (11) and a top (12), wherein the top surface (12) of the wood panel support element (10) is provided with a coating (20) as a separating layer which covers the top surface (12) of the wood panel support element (10) over a surface, preferably substantially completely, and is configured to prevent a surface material contact between the top surface (12) of the wood panel support element (10) on the one hand and an in-situ concrete and / or an in-situ concrete layer (40) on the other hand, wherein the upper surface (12) is provided with a plurality of composite anchors (30) anchored in the timber support element (10) and spaced apart from each other, wherein each composite anchor (30) has a timber anchoring section (31) anchored in the timber panel support element (10) and a concrete anchoring section (32) projecting from the top (12) of the timber panel support element (10), which is configured to be embedded in a cast-in-place concrete layer (40), wherein the composite anchors (30) penetrate the coating (20).

Description

[0001] The invention relates to a semi-finished ceiling element as a prefabricated, transportable and installable ceiling element for the production of a composite ceiling by applying cast-in-place concrete to form a cast-in-place concrete layer, and furthermore also to a composite ceiling produced by means of such a semi-finished ceiling element.

[0002] The present disclosure relates to the field of ceiling construction, in particular to precast or element ceiling systems for producing a load-bearing ceiling by applying cast-in-place concrete (topping concrete) onto a prefabricated ceiling element. Such systems have long been used in building construction because they combine industrial prefabrication with a monolithic ceiling effect produced on site.

[0003] In the current state of the art, precast concrete slabs, also known as element slabs, semi-precast slabs, or lattice girder slabs, are widely used. These involve the provision of a factory-manufactured semi-precast slab element made of reinforced concrete, typically in the form of a thin reinforced concrete slab with integrated reinforcement and lattice girders. This element is installed on-site and then completed by pouring cast-in-place concrete to form a finished reinforced concrete slab. The bond between the semi-precast slab element and the cast-in-place concrete is ensured, in the current state of the art, primarily through surface roughness and the lattice girders / diagonals or the reinforcement added on-site.

[0004] Precast concrete slabs offer the advantage of reducing formwork requirements and providing a largely smooth ceiling surface compared to cast-in-place concrete slabs. The cast-in-place concrete simultaneously serves to complete the load-bearing capacity and integrate additional reinforcement. However, the load-bearing capacity of the precast slab element in its installed state must be regularly considered during transport and assembly.

[0005] Furthermore, it must be considered that concrete as a building material involves a considerable amount of material and that the cement content in particular influences the CO2 balance of a building. In practice, therefore, criteria relating to life cycle assessment, resource efficiency, and CO2 balance are increasingly being used in the planning and selection of ceiling structures, in addition to structural and construction-related requirements.

[0006] Another aspect concerns deconstruction and reuse. While the recycling of concrete (e.g., as recycled aggregate) is quite established in practice, the reuse of entire concrete components is currently rather rare. In construction practice, this means that monolithic or strongly bonded ceiling structures are often only separable with considerable effort.

[0007] Against this technical and market background, when selecting a ceiling structure, aspects such as weight, transport logistics, CO2 balance, and deconstruction and recycling capabilities can play a role, depending on the project specifications, in addition to the structural and practical construction requirements.

[0008] Timber-concrete composite (TCC) slabs are also known in the prior art, in which a concrete layer is arranged on a timber load-bearing member and the composite action between timber and concrete is achieved by means of shear connectors to create a joint load-bearing capacity. Such systems are used in construction practice, particularly in connection with the strengthening of existing timber joist slabs, whereby the concrete layer is often produced as a topping on an existing timber slab and coupled to the timber load-bearing member via shear connectors, for example, screw connectors, dowels, or bonded anchors. Such composite structures are designed for the structural cooperation of the layers in their installed state. Subsequent dismantling can therefore involve separate separation and disassembly efforts, especially if, in the composite state, there are large-area adhesions, local penetrations, or similar structural conditions that complicate layer-by-layer separation.

[0009] Accordingly, the object of the present invention is to provide a semi-finished ceiling element that can be manufactured industrially in a simple manner as a prefabricated, transportable and installable ceiling element, which allows the production of a composite ceiling by applying cast-in-place concrete to form a cast-in-place concrete layer and takes into account requirements for handling, weight and deconstruction capability without impairing the load-bearing capacity and serviceability required for building construction.

[0010] This task is solved using the features of the independent claims. Advantageous embodiments are the subject of the dependent claims relating thereto.

[0011] According to the invention, a semi-finished ceiling element is proposed for the production of a composite ceiling by applying cast-in-place concrete to form a cast-in-place concrete layer, wherein the semi-finished ceiling element comprises a timber panel support element with a bottom and a top surface. The top surface of the timber panel support element is provided with a coating as a separating layer, which covers the top surface of the timber panel support element over its entire area, preferably substantially completely, and is configured to prevent any material contact between the top surface of the timber panel support element on the one hand and cast-in-place concrete and / or a cast-in-place concrete layer on the other.Furthermore, the top surface is provided with a plurality of composite anchors spaced apart and anchored in the timber panel support element, each composite anchor having a timber anchorage section embedded in the timber panel support element and a concrete anchorage section projecting from the top surface of the timber panel support element, configured to be embedded in a layer of cast-in-place concrete. The composite anchors also penetrate the coating.

[0012] The solution according to the invention thus provides a semi-finished ceiling element as a prefabricated, transportable, and installable ceiling element, which, in contrast to concrete filigree slabs, uses a timber panel support element as the load-bearing semi-finished element and thus forms a "timber filigree slab" as a semi-finished component for the production of a composite slab. This results in a prefabricated ceiling element that is designed as a complete, transportable, and installable ceiling component and whose handling and installation logic is similar to the established handling of concrete filigree slabs in building construction.

[0013] Furthermore, by designing the semi-finished ceiling element as a wooden panel load-bearing element, a weight reduction can be achieved compared to a similar semi-finished ceiling element made of reinforced concrete, thereby facilitating transport, handling and installation on the construction site and at the same time making larger element dimensions possible under given transport and assembly conditions.

[0014] By designing the timber panel support element with a defined underside and a defined top side, a clear functional assignment of the surfaces is ensured. The underside can be used as the ceiling soffit, while the top side serves as a bearing and working surface for the subsequent application of the cast-in-place concrete. This allows the prefabricated ceiling element to be used in construction practice as a support for the applied cast-in-place concrete layer without additional formwork, while the final load-bearing capacity of the composite ceiling is achieved by adding the cast-in-place concrete to complete the cast-in-place concrete layer.

[0015] The coating applied to the top surface, acting as a separating layer, ensures that the top surface of the timber panel support element is completely, and preferably substantially entirely, shielded from the cast-in-place concrete and the subsequent cast-in-place concrete layer. This prevents any surface-level material contact between the cast-in-place concrete or layer and the timber panel support element. As a result, the formation of a surface-level adhesion or a surface-level bond between the wood and concrete on the top surface is avoided, so that the bond is not achieved through surface contact, but rather through the structurally defined bond anchors provided for this purpose.Simultaneously, the coating provides a defined, flat separation plane on the top surface of the timber panel support element. This plane allows the cast-in-place concrete layer to be separated from the timber panel support element during deconstruction, without having to overcome any extensive material contact between the wood and concrete. This facilitates the separation of the cast-in-place concrete layer from the timber panel support element, where the separation process is not hampered by large areas of adhering concrete residue or extensive bond zones. As a result, the timber panel support element remains in a condition that facilitates reuse or material recycling after separation. Furthermore, the flat covering of the top surface reduces the exposure of the wood to cement grout that may occur during the placement of the cast-in-place concrete.with moisture from the cast-in-place concrete, which reduces the penetration of concrete components into surface pores, joints or wood structure and further supports the separability along the separation plane.

[0016] The coating can be single-layered or multi-layered, whereby in the case of multi-layered construction several, in particular superimposed, layer layers together form the separating layer to prevent the surface material contact between the top of the wooden panel support element and the cast-in-place concrete and / or cast-in-place concrete layer.

[0017] By designing each composite anchor with a timber anchorage section embedded in the timber panel support element and a concrete anchorage section projecting from the top of the timber panel support element, a mechanical connection is established between the timber panel support element and the cast-in-place concrete layer. The timber anchorage section provides the anchorage of the composite anchor within the timber panel support element, while the concrete anchorage section is embedded in the cast-in-place concrete layer after the concrete has been poured. Thus, the force transfer between the cast-in-place concrete layer and the timber panel support element occurs via the majority of the composite anchors, similar to the process in timber-concrete composite slabs. Accordingly, the present teaching also provides a composite action similar to that of a timber-concrete composite slab between the timber panel support element and the cast-in-place concrete layer via composite anchors.However, the timber panel support element is designed as a load-bearing component of a semi-finished ceiling element, which is industrially prefabricated, with the coating and the arrangement of the bonded anchors also preferably carried out during the manufacturing process of the timber filigree ceiling. This allows, in particular, the consistent quality of the surface-wide formation of the separation layer and the execution of the penetrations by the bonded anchors, thus simplifying assembly on the construction site and supporting the functional reliability of the separation layer in its installed state.

[0018] Although it is generally possible to apply the coating as a separating layer to the timber panel support element on-site and / or to insert the bonded anchors into the timber panel support element on-site, a significant advantage of the present teaching lies in preparing the coating and / or the bonded anchors at the factory. Accordingly, a first particularly preferred embodiment provides for the coating to be applied to the timber panel support element at the factory. This provides the semi-finished ceiling element as a prefabricated component in a defined, reproducible state, so that the separating layer on the top surface of the timber panel support element is already functionally present before transport and installation, thus eliminating on-site work steps.Alternatively, but preferably additionally, a design in which the majority of the composite anchors are factory-installed in the timber panel support element ensures that the fasteners crucial for the subsequent composite action are already provided in a defined arrangement and embedment depth before transport and installation, thus saving time-consuming on-site work steps. The insertion of the composite anchors can also be carried out robotically or automatically, which is virtually impossible on-site.

[0019] Overall, this results in a semi-finished ceiling element that, as a fully transportable and installable ceiling element, corresponds in its deployment logic to a precast concrete slab, because the essential functions for the construction site are already prefabricated in the factory and, on site, essentially only the installation and the application of the cast-in-place concrete to form the in-situ concrete layer need to be carried out. This makes the solution according to the invention usable in construction practice as a 1:1 substitute for a precast concrete slab, without the execution of coatings and bonded anchors on the construction site influencing or slowing down the process.

[0020] The invention thus primarily provides a semi-finished system designed for prefabrication and on-site addition, which in terms of handling and logistics is similar to established filigree slab practices, but significantly reduces the use of concrete material.

[0021] According to a particularly preferred embodiment, the timber panel support element is formed by a cross-laminated timber (CLT) panel, preferably a multi-layer CLT panel, or by a laminated timber ceiling, preferably a glued or doweled laminated timber ceiling. This design provides the timber panel support element as a plate-shaped, load-bearing component with a defined underside and a defined top surface, making it suitable as a prefabricated, transportable, and installable ceiling element. A multi-layer CLT panel promotes high dimensional stability and reproducible geometry, while a laminated timber ceiling, especially in a glued or doweled configuration, provides robust, large-area load-bearing capacity as a timber panel support element.In both cases, this creates a panel structure that forms a defined anchoring base for the composite anchors embedded in the wooden panel support element, thereby supporting the production of the semi-finished ceiling element as a ceiling part that can be installed as a whole.

[0022] A timber panel load-bearing element within the meaning of this disclosure is understood to be a planar, panel-like timber component that forms a continuous slab surface and extends across a ceiling span. The timber panel load-bearing element is thus not designed as a mere beam, frame, or lattice structure, but rather provides a self-contained, large-area load-bearing element that can form a ceiling soffit across its surface and provides a continuous bearing surface on its upper surface for the application of cast-in-place concrete. In particular, the timber panel load-bearing element is designed such that, as a semi-prefabricated ceiling element, it assumes a planar load-bearing and installation function in its assembled state, whereby the load transfer is not exclusively via linear or point load-bearing elements, but rather via the slab action of the timber panel load-bearing element.In a cross-laminated timber (CLT) panel configuration, this panel effect is achieved through the interconnected, preferably crosswise arranged, layers of wood. In a plank-stacked ceiling configuration, the panel effect is achieved by combining the adjacent boards into a single, continuous panel component, with the gluing or doweling creating a load-bearing connection between the boards, so that the wood panel element acts as a cohesive, load-bearing ceiling element.

[0023] According to a particularly preferred embodiment, the bonded anchors are designed to penetrate the coating, preferably in a transition area between the concrete anchoring section and the timber anchoring section, in a substantially tight manner. Specifically, the coating is configured to seal around the bonded anchors in the penetration area, effectively preventing the ingress of cement paste and / or cast-in-place concrete beneath the coating and thus onto the top surface of the timber support element. This design ensures that the coating reliably maintains its separating function on the top surface, even in the area of ​​the bonded anchor penetrations. In particular, it prevents cement paste, as a finely divided, flowable phase of the cast-in-place concrete, from entering the area beneath the coating and causing undesirable material contact between the cast-in-place concrete and / or the timber support element.The seal forms a barrier between the in-situ concrete layer and the top surface of the timber support element. This ensures that the separation plane remains functionally effective not only across the entire surface but also locally at the penetration points, preventing any localized or ring-shaped undercutting along the coating. The preferred arrangement of the tight penetration in the transition area between the concrete anchorage section and the timber anchorage section is particularly advantageous from a technical standpoint because this area is typically located directly on or near the top surface, and therefore a sealing effect is needed precisely where undercutting of the coating would otherwise begin.

[0024] For the purposes of this disclosure, "essentially tight penetration" of the coating means that a sealing effect is provided in the penetration area between the respective bonded anchor and the coating, such that cement paste and / or cast-in-place concrete do not penetrate under the coating, or only to an extent that is technically negligible for the separation function. In particular, this does not require absolute tightness in the sense of a fluid-tight seal under every conceivable load condition, but rather a sealing effect that is appropriate to the injection and flow processes that typically occur during the application, distribution, and hardening of cast-in-place concrete and prevents any significant seepage under the coating.The coating preferably surrounds the bonded anchor tightly, in particular in a ring shape, whereby the enclosure can be realized, for example, by a material design of the coating that conforms to the bonded anchor, by a locally compacted or deformed edge zone of the coating, by an additional sealing zone or by another design that provides the sealing effect.

[0025] According to a particularly preferred embodiment, the top and / or bottom of the timber panel support element is essentially flat. This provides the timber panel support element as a planar component with defined, large-area functional surfaces. An essentially flat top surface particularly facilitates the uniform application of the coating as a separating layer, as well as the uniform application and distribution of the cast-in-place concrete for forming the concrete layer, because local depressions, raised areas, or profile-like structures that could contribute to local material accumulation, uneven layer thicknesses, or local undercutting of the coating are reduced.In contrast, a substantially flat underside facilitates the creation of a uniform ceiling soffit and supports the use of the semi-finished ceiling element as a ready-to-install ceiling element that can provide a defined soffit without additional measures. For the purposes of this disclosure, "substantially flat" means that the respective surface of the wood panel support element is designed in such a way that it provides a flat surface in a practical construction sense across the relevant area of ​​the wood panel support element. This does not exclude manufacturing and material-related tolerances, minor unevenness, wood grain, joint patterns, or minor steps, particularly in the area of ​​panel joints, as long as these do not impair the function of the top surface as a substrate for coatings and cast-in-place concrete, or the function of the underside as a ceiling soffit, in a technically relevant way.

[0026] According to a particularly preferred embodiment, the underside of the wood panel support element is configured to form a ceiling soffit and / or the wood panel support element has a planed or sanded surface on its underside as a visible surface. This ensures that the semi-finished ceiling element provides a defined underside in its installed state, which can be used directly as a ceiling soffit. In particular, a planed or sanded surface achieves a uniform and visually homogeneous visible surface, so that after the semi-finished ceiling element has been installed, no additional cladding or subsequent processing is required to provide a suitable underside.The design of the underside as a ceiling soffit is particularly important for its character as a semi-finished ceiling element, because it allows the function of "permanent formwork" and a finished ceiling soffit to be combined in a single component. For the purposes of this disclosure, an "underside configured as a ceiling soffit" means that, in its installed state, the underside forms the ceiling surface facing the room and can either be left directly visible or at least used as a soffit without structural modifications. A "visible surface" includes, in particular, surfaces that have been post-processed by planing and / or sanding to achieve a defined surface quality with reduced roughness and a defined appearance.

[0027] According to a particularly preferred embodiment, the coating is detachably and / or removablely bonded to the top surface of the timber panel support element. This provides the separating layer not only as a separating plane during the manufacture and use of the composite slab, but also in a way that allows for the subsequent removal of the coating as a separate component. In particular, this allows for the separation of the cast-in-place concrete layer from the timber panel support element along the separation plane during deconstruction, without the coating necessarily having to remain permanently attached to the timber panel support element. Additionally, the detachability or removability of the coating can facilitate handling during the manufacturing or assembly process, because, for example, on-site renewal, partial repair, or adjustment of the coating is possible without having to replace the timber panel support element itself.A removable connection thus enables a defined degree of disassembly of the coating. For the purposes of this disclosure, "removably connected" or "detachably connected" preferably means that the coating is connected to the top surface of the wood panel support element in such a way that it can be detached from the top surface using a suitable separating or peeling process, without necessarily causing irreversible damage to the coating and / or the wood panel support element. This includes the possibility that local damage may occur during removal, as long as the connection is not designed from the outset as a permanent, non-detachable bond.

[0028] According to a particularly preferred embodiment, the coating is formed by a protective layer that is bonded to the top surface by means of an adhesive, preferably an adhesive, and most preferably an adhesive layer arranged on the protective layer. It is preferably provided that the protective layer is bonded to the top surface over its entire area. This results in a structurally manageable protective layer that can be reliably applied to the top surface of the timber panel support element and provides a defined separation and shielding function. The bonding by means of an adhesive, in particular an adhesive, enables reproducible fixation of the protective layer to the top surface, so that the protective layer remains securely in place during transport, installation, and the application of the cast-in-place concrete, and retains its full-surface coverage.An adhesive layer applied to the protective layer allows for particularly easy application, because the protective layer can be provided as a prefabricated, ready-to-use semi-finished product and can be attached to the top surface of the wood panel support element by pressing it into place. The preferably full-surface bond particularly promotes a uniform adhesion of the protective layer across the entire surface, reduces local voids or areas of delamination, and can thus further reduce the risk of local infiltration of the protective layer by cement grout and / or cast-in-place concrete. For the purposes of this disclosure, an "adhesive" is understood to be a material suitable for fixing the protective layer to the top surface of the wood panel support element, in particular by adhesion and / or cohesion.An “adhesive layer arranged on the protective layer” includes in particular factory-applied, continuous or discontinuous adhesive layers, whereby the full-surface bond represents a preferred special case and other application methods of the adhesive may still be included in the scope of protection.

[0029] According to a particularly preferred embodiment, the protective layer is formed by a nonwoven fabric or a plastic film, preferably with a material thickness of 0.1 mm to 3.0 mm. This allows the coating to function as a separating layer in the form of a technically easy-to-handle, flat protective layer that can be reliably applied to the top surface of the wooden panel support element and simultaneously provides a defined separation effect against the applied cast-in-place concrete or the subsequent cast-in-place concrete layer. A nonwoven fabric is particularly suitable because it provides a flexible, adaptable surface structure that can conform to surface contours and simultaneously form a robust, mechanically resilient separating layer across its surface.A plastic film is particularly suitable because it provides a substantially closed, planar barrier that can offer a particularly pronounced separation effect against cast-in-place concrete components and cement paste. The material thickness, ranging from 0.1 mm to 3.0 mm, allows for sufficient mechanical stability of the protective layer for transport, installation, and concrete placement, while simultaneously enabling a low overall thickness, so that the protective layer only minimally affects the geometry of the precast slab element. For the purposes of this disclosure, a "nonwoven layer" is understood to be a planar, fiber-based layer, which may be formed from synthetic and / or natural fibers and is designed as a self-contained, manageable roll.For the purposes of this disclosure, a "plastic film" is to be understood as a planar, preferably substantially closed film made of a plastic material, which can be supplied as a roll and can be arranged as a separating layer on the top side of the wooden board support element.

[0030] According to a particularly preferred embodiment, the composite anchors are arranged in a defined grid, preferably with a first grid dimension in a longitudinal direction of the timber panel support element and a second grid dimension in a transverse direction of the timber panel support element. This provides the majority of the composite anchors in a reproducible, structurally defined arrangement, so that the composite action between the timber panel support element and the cast-in-place concrete layer can be precisely and uniformly adjusted across the surface. A defined grid particularly promotes a uniform distribution of the forces introduced into the composite anchors across the surface area of ​​the precast slab element and thus supports a defined, predictable load-bearing capacity of the subsequent composite slab.By specifying a first grid dimension in the longitudinal direction and a second grid dimension in the transverse direction, a two-dimensional grid definition is provided, which simplifies the design and manufacturing process and supports the prefabrication of the semi-finished ceiling element because the positions of the composite anchors are clearly defined in both main directions of the timber panel load-bearing element. At the same time, a grid arrangement can facilitate simplified coordination with other structural boundary conditions, such as element dimensions, joint areas, bearing zones, or reinforcement arrangements, without requiring an irregular, difficult-to-reproduce positioning of the composite anchors.For the purposes of this disclosure, a “defined grid” preferably means that the composite anchors are arranged at recurring intervals, which are described by grid dimensions in at least two different directions of the timber panel support element. This includes the possibility that deviations from the basic grid may be provided in edge areas, support areas, or functional areas, as long as the grid arrangement as such structurally determines the positioning of the composite anchors in the surface.

[0031] According to a particularly preferred embodiment, the concrete anchoring section of the bonded anchor projects obliquely from the top surface of the timber panel support element. This provides a geometry for the bonded anchors in which the concrete anchoring section to be embedded in the cast-in-place concrete layer does not run perpendicular to the top surface, but rather extends from it at an oblique angle. Due to the inclined arrangement of the concrete anchoring section, both vertical and horizontal shear force components can be absorbed and transferred into the structure via the bonded anchors in the composite action between the timber panel support element and the cast-in-place concrete layer, thereby promoting a particularly effective, shear-resistant mechanical connection between the timber panel support element and the cast-in-place concrete layer.At the same time, by selecting an inclined angle, an advantageous balance can be achieved between high shear transfer in the cast-in-place concrete layer on the one hand and sufficient embedment depth or anchorage length in the timber panel support element on the other. For the purposes of this disclosure, "inclined angle" means that the concrete anchorage section projects at an angle other than 90° to the plane of the top surface of the timber panel support element, the angle being chosen such that the concrete anchorage section can be embedded within the cast-in-place concrete layer.

[0032] According to a particularly preferred embodiment, the angle of inclination of the concrete anchorage sections is 30° to 60°, preferably 40° to 50°, and most preferably 45°. Within this angle range, a particularly high force absorption capacity can be achieved while simultaneously ensuring high connection stability. In particular, an angle of inclination of 45° promotes a uniform distribution of forces across tension and compression zones and simultaneously ensures a deep embedment depth of the composite anchors in the timber panel support element. By selectively choosing the angle of inclination, a higher load-bearing capacity of the composite system can be achieved, while at the same time increasing the fatigue resistance of the connection. This contributes to increased service life and reliability, especially in dynamically loaded components such as ceiling elements.

[0033] According to a particularly preferred embodiment, the composite anchor has an anchor shaft with an end-mounted anchor head serving as a tool attachment. Viewed along the longitudinal direction of the anchor shaft, this attachment is followed by the concrete anchoring section, which, in the installed state, runs within a layer of cast-in-place concrete. Adjoining this concrete anchoring section is the timber anchoring section, which, in the installed state, can be anchored in the timber support element. It is preferably provided that the timber anchoring section is at least partially provided with a timber thread, by means of which the timber anchoring section, and thus the composite anchor, can be screwed into the timber support element. This provides a composite anchor that can be installed as a one-piece connecting element in a defined orientation, with the anchor head serving as a tool attachment enabling targeted torque transmission to the anchor shaft.By positioning the timber anchoring section at the end downstream of the concrete anchoring section in the longitudinal direction of the anchor shaft, the composite anchor is designed such that, when screwed into the timber panel support element, the timber anchoring section penetrates or engages directly with the timber panel support element, while the concrete anchoring section protrudes from the top of the timber panel support element, ready for subsequent integration into the cast-in-place concrete layer. The timber thread, provided at least in some areas, creates a defined positive fit in the wood material, allowing the composite anchor to be anchored in the timber panel support element without additional fasteners. This facilitates reproducible, assembly-oriented anchoring of the majority of composite anchors, similar to a factory-prepared, semi-finished ceiling element.

[0034] According to a particularly preferred embodiment, the composite anchor is made at least partially, and preferably entirely, from an unhardened steel material, preferably comprising an unhardened concrete anchoring section and an unhardened wood anchoring section. It is particularly advantageous that the unhardened wood anchoring section is provided, at least partially, with a wood thread produced by cold forming, by means of which the wood anchoring section, and thus the composite anchor, can be screwed into the wood panel support element. This provides a composite anchor that exhibits ductility suitable for screwing into a wood panel support element, so that the installation stresses during screwing, in particular when applying the screwing torque via the anchor head, can be reliably absorbed.The formation of the wood thread through cold forming enables a geometrically defined thread shape to create a positive connection in the wood material. This wood thread simultaneously improves the screwability of the wood anchoring section and promotes consistent anchoring quality for the majority of composite anchors in the timber panel load-bearing element. This facilitates the robust, process-reliable production of a semi-finished ceiling element with factory-installed composite anchors, while the concrete anchoring section remains an integral part of the composite anchor, ready for embedding in the cast-in-place concrete layer.Particularly preferred is a design in which the unhardened wooden anchoring section having the wooden thread has a tensile load-bearing capacity that is a maximum of 0.5 kN to 10.0 kN greater than the tensile load-bearing capacity of this wooden anchoring section in defined screw-in timbers with a wood density of 310 kg / m³. 3 up to 500 kg / m² 3 , based on a screw-in angle in the wood of 40° to 50°, wherein it is preferably provided that the concrete anchoring section is designed with a larger shaft diameter at least in the transition area to the wood anchoring section than a shaft area of ​​the wood anchoring section defining the thread core diameter.

[0035] According to a particularly preferred embodiment, the semi-finished ceiling element has a width of 2.0 m to 2.60 m, preferably 2.30 m to 2.55 m, and / or a length of 5.0 m to 12.0 m, preferably 6.0 m to 10.0 m. This provides element dimensions that allow the semi-finished ceiling element to be used as a prefabricated, transportable, and installable ceiling element in a format suitable for transport on, for example, a standard semi-trailer without special permits. This facilitates logistically simple provision of the semi-finished ceiling element as a "fully installable" ceiling section, because the element geometry is selected to be manageable under typical transport conditions, without requiring project- or route-specific special transport requirements to be the norm.This also promotes standardized prefabrication and a recurring installation practice with large-format elements, comparable to the handling logic of filigree concrete ceilings.

[0036] According to a particularly preferred embodiment, the timber panel support element has a material thickness of 40 mm to 120 mm, preferably 50 mm to 100 mm, and most preferably 60 mm to 80 mm. This provides a material thickness for the timber panel support element that, on the one hand, is comparable to the typical thicknesses of precast concrete slabs, which are usually in the range of approximately 50 mm to 70 mm, and, on the other hand, takes into account the material and structural differences between timber and concrete. In particular, timber has a lower density and exhibits different structural mechanics than reinforced concrete, so that a potentially greater thickness range for the timber panel support element compared to typical precast concrete slabs facilitates a practical design of the prefabricated slab element as a load-bearing element that can be installed as a single unit.At the same time, specifying the material thickness in the aforementioned areas supports compatibility with existing ceiling structures, because the semi-finished ceiling element's structural height can be linked to established system heights, thus facilitating replacement or substitution without a fundamental system change. Furthermore, the installation logic of the composite ceiling to be constructed is maintained, as reinforcement can still be incorporated and cast-in-place concrete is applied to form the in-situ concrete layer. Therefore, in practice, the semi-finished ceiling element can be integrated as a timber filigree slab using a process comparable to that of concrete filigree slabs.

[0037] The invention further relates to a composite ceiling with at least one semi-finished ceiling element as described above and with a layer of cast-in-place concrete applied to the at least one semi-finished ceiling element, in which the concrete anchoring sections of the composite anchors are embedded, wherein the coating of the top of the at least one semi-finished ceiling element forms a separating layer between the cast-in-place concrete layer and the top of the timber support element, in particular for a clean-up deconstruction by separating the cast-in-place concrete layer from the timber support element of the at least one semi-finished ceiling element.This creates a defined, planar separation plane in the completed composite slab between the cast-in-place concrete layer and the top surface of the timber panel support element. This allows the cast-in-place concrete layer to be separated from the timber panel support element along this separation plane during deconstruction, without having to overcome a planar material contact between the concrete and the timber on the top surface. At the same time, the composite action of the slab remains structurally defined by the concrete anchorage sections embedded in the cast-in-place concrete layer and the timber anchorage sections embedded in the timber panel support element. This ensures both a load-bearing connection between the cast-in-place concrete layer and the timber panel support element, and prevents the separability from being limited by an uncontrolled planar bond mechanism.This supports a deconstruction concept in which the cast-in-place concrete layer and the wooden panel support element are each available as separate material fractions after separation.

[0038] According to a particularly preferred embodiment, the cast-in-place concrete layer comprises reinforcement, preferably mesh reinforcement and / or bar reinforcement, arranged above the coating. This allows the reinforcement to be positioned within the cast-in-place concrete layer in the manner customary for reinforced concrete or cast-in-place concrete additions, without impairing the function of the coating as a separating layer. In particular, the coating remains as a continuous separating plane directly at the top of the timber panel support element, while the reinforcement is arranged above it and thus lies entirely within the cast-in-place concrete layer. This enhances the load-bearing capacity of the cast-in-place concrete layer through the reinforcement, while the separating layer continues to prevent full-surface material contact between the cast-in-place concrete layer and the timber panel support element.

[0039] According to a further particularly preferred embodiment, at least one additional layer is arranged between the coating and the cast-in-place concrete and / or the cast-in-place concrete layer, preferably being formed by a fleece. This clarifies that the separating effect of the coating is not limited to direct contact with the cast-in-place concrete or the cast-in-place concrete layer, but that the layer structure above the coating can be supplemented by one or more intermediate layers. Furthermore, this enables a robust design in practical construction, in which an additional layer, for example as a fleece, can act as a protective, separating, and / or leveling layer between the coating and the cast-in-place concrete without altering the basic structure consisting of the timber panel support element, the coating as a separating layer, and the bonded anchors penetrating the coating.In particular, the coating continues to act as a separating layer on the top side of the wooden panel support element, while the additional layer is arranged above the coating, thus maintaining the functional assignment of the separating layer and the composite effect achieved structurally via the bonded anchors unchanged.

[0040] It should therefore be explicitly clarified once again that at least one additional layer can be placed between the coating (which may consist of multiple layers) and the cast-in-place concrete and / or the cast-in-place concrete layer. This means that the separating effect of the coating as a separating layer is not limited to a layer structure where the coating directly abuts the cast-in-place concrete or the cast-in-place concrete layer, but that the layer structure in the area above the coating can also be supplemented by one or more intermediate layers. Such intermediate layers may be included for practical construction reasons without altering or compromising the basic structure consisting of the timber panel support element, the coating as a separating layer, and the bonded anchors penetrating the coating.

[0041] A method for manufacturing an industrially produced semi-finished ceiling element as described above preferably comprises the following steps: a) Providing a timber panel support element with a bottom and a top, b) Applying, preferably factory-applying, a coating as a separating layer to the top surface of the wood panel support element, wherein the coating covers the top surface of the wood panel support element over a surface area, preferably substantially completely, c) Anchoring, preferably factory anchoring, a plurality of bonded anchors in the timber panel support element such that the bonded anchors penetrate the coating and a timber anchoring section is anchored in the timber panel support element and a concrete anchoring section projects from the top of the timber panel support element, d) optionally, transporting the formed semi-finished ceiling element to a construction site.

[0042] The invention is explained in more detail below with reference to a drawing, using an example and a schematic diagram.

[0043] They show: Fig. 1 a schematic exploded and sectional view of an exemplary assembly of a semi-finished ceiling element according to the invention, Fig. 2 the semi-finished ceiling element of the Fig. 1 in the assembled state, in which the semi-finished ceiling element forms a prefabricated, transportable and installable ceiling element, and Fig. 3 a schematic detailed representation of a composite slab with at least one semi-finished slab element according to Fig. 2.

[0044] Fig. Figure 1 shows a schematic exploded and sectional view of the basic structure of an exemplary semi-finished ceiling element 1 according to the invention. The semi-finished ceiling element 1 comprises a wooden panel support element 10 with a bottom surface 11 and a top surface 12. Both the bottom surface 11 and the top surface 12 are, by way of example, essentially flat. Furthermore, the bottom surface 11 of the wooden panel support element 10 can form a ceiling soffit and, for example, have a planed or sanded surface that creates a visible surface. This allows the bottom surface 11 of the semi-finished ceiling element 1 to serve directly as a finished ceiling soffit in the installed state, without the need for additional coverings or suspended ceilings.

[0045] The timber panel support element 10 can be formed here by a multi-layered cross-laminated timber panel or alternatively by a cross-laminated timber ceiling and can further, for example, have a material thickness of 60 mm to 80 mm.

[0046] Above the top surface 12, a coating 20 is shown as a separating layer, which in the exemplary embodiment shown is designed as an adhesive protective film and protects the top surface 12 of the wooden panel support element 10 in the Fig. The protective film, made of plastic, can have a thickness of 0.5 mm, covering the entire surface of the connected or assembled parts shown in the 2nd shown state.

[0047] Furthermore, a plurality of composite anchors 30 are shown schematically, which in the assembled state, which in particular the Fig. 2 and Fig. 3, which can be clearly seen, are each anchored in the wooden panel support element 10 and essentially penetrate the coating 20 completely. Each composite anchor 30 has, as is particularly evident from the Fig. As can be seen in Figure 3, a timber anchoring section 31 and a concrete anchoring section 32 are provided, wherein the timber anchoring section 31 is anchored in the timber panel support element 10 in a manner to be described below, while the concrete anchoring section 32 projects from the top 12 of the timber panel support element 10 to be embedded in a cast-in-place concrete layer 40 in a manner to be described below. Fig. 3) to be integrated. The penetration of the coating 20 by the respective bonded anchor 30 takes place in a transition area 33 between concrete anchoring section 32 and timber anchoring section 31. The coating 20 is configured to seal around the respective bonded anchors 30 in the area of ​​penetration in such a way that the penetration of cement grout and / or cast-in-place concrete under the area of ​​the coating 20 and thus onto the top surface 12 of the timber panel support element 10 is essentially prevented.

[0048] Fig. Figure 2 shows the semi-finished ceiling element 1 of the Fig. 1 in the preferred assembled state, in which the semi-finished ceiling element 1 can be provided as a prefabricated, transportable and installable ceiling element and delivered from the factory. The coating 20, formed by a protective film, is arranged on the top surface 12 of the timber panel support element 10, preferably detachably and removablely bonded. The composite anchors 30 are anchored in the timber panel support element 10 and penetrate the coating 20 in the transition area 33, such that the concrete anchorage sections 32 of the composite anchors 30 project from the top surface 12 of the timber panel support element 10 above the coating 20.

[0049] Fig. Figure 3 shows a schematic detail representation of a composite slab 2 with at least one semi-finished slab element 1 according to Fig. 2, in which cast-in-place concrete is applied to the semi-finished ceiling element 1 and supplemented or hardened to form a cast-in-place concrete layer 40. The cast-in-place concrete layer 40 lies above the coating 20, while the coating 20 is arranged on the top surface 12 of the timber panel support element 10 and forms a separating layer between the cast-in-place concrete layer 40 and the top surface 12 of the timber panel support element 10. A composite anchor 30 is shown as an example and penetrates the coating 20 in the transition area 33. The timber anchorage section 31 of the composite anchor 30 is anchored in the timber panel support element 10, while the concrete anchorage section 32 is embedded in the cast-in-place concrete layer 40, so that the composite action between the timber panel support element 10 and the cast-in-place concrete layer 40 is structurally provided by the composite anchor(s) 30.

[0050] The composite anchors 30 have an anchor shaft 35 and an end-end anchor head 34 as a tool attachment point. Furthermore, the wood anchoring section 31 is provided, at least in part, with a wood thread 36, by means of which the wood anchoring section 31, and thus the composite anchor 30, can be screwed into the wood panel support element 10. The in Fig. The selected representation serves to illustrate the basic integration of the composite anchor 30 into the timber panel support element 10 and the cast-in-place concrete layer 40, as well as the arrangement of the coating 20 as a separating layer, and is not to scale.

[0051] The Fig. 1 and Fig.Figure 2 also schematically and in principle shows a preferred arrangement of the bonded anchors 30 in the semi-finished ceiling element 1. With reference to a span center 37, shown here only as an example, the bonded anchors 30 are arranged to the left and right of the span center 37 at the same angle of inclination, here for example approximately 45°, but in opposite directions. This provides a shear-resistant bond between the cast-in-place concrete layer 40 and the timber panel support element 10.

[0052] Under a vertical load on the composite slab 2, the force distribution in the cast-in-place concrete layer 40 is dominated by compressive forces with a load peak in the area of ​​the span 37, while the force distribution in the timber panel support element 10 is dominated by tensile forces with a corresponding load peak. The oblique arrangement of the composite anchors 30 enables an effective transfer of these tensile and compressive forces between the cast-in-place concrete layer 40 and the timber panel support element 10, thus forming a load-bearing composite component.

[0053] The composite anchors 30 can be arranged in a defined grid on the top surface 12 of the wood panel support element 10, e.g. by a first grid dimension in a longitudinal direction of the wood panel support element 10 and by a second grid dimension in a transverse direction of the wood panel support element 10, which is not explicitly shown here.

[0054] In conclusion, the figures as a whole illustrate that the inventive design of the semi-finished ceiling element 1, comprising the timber panel support element 10, the coating 20 arranged on the upper surface 12 as a separating layer, and the bonded anchors 30 penetrating the coating 20, provides a composite structure in which the bond between the timber panel support element 10 and the cast-in-place concrete layer 40 is achieved structurally exclusively via the bonded anchors 30 and not via a surface-level material contact between wood and concrete. The surface-level material contact between the upper surface 12 of the timber panel support element 10 and the cast-in-place concrete or the cast-in-place concrete layer 40 is specifically prevented by the coating 20 as a separating layer, thus avoiding the formation of an uncontrolled surface bond between wood and concrete.

[0055] In the event of dismantling, this design allows the cast-in-place concrete layer 40 to be selectively separated from the timber panel support element 10 without having to overcome large areas of adhering concrete residue or extensive bonded composite zones. The separation process is instead limited to releasing the structural bond via the composite anchors 30, while the coating 20 facilitates separation along a substantially flat and defined separation plane. This promotes controlled, minimally destructive dismantling of the composite slab 2.

[0056] After separation, the timber panel support element 10 remains in a state that facilitates reuse as a building component or at least separate material recycling, while the cast-in-place concrete layer 40 can also be treated separately. The figures thus illustrate that the structure according to the invention not only ensures the load-bearing capacity and composite action required for building construction in its service state, but also creates the conditions for improved separability and deconstruction of the ceiling system. Reference symbol list 1 semi-finished ceiling element 2 Composite ceiling 10 wooden panel support elements 11. Bottom 12 Top 20 Coating / protective film 30 composite anchors 31 Timber anchoring section 32 Concrete anchoring section 33 Transition area 34 Anchor head 35 Anchor shaft 36 wood threads 37 Field Center 40 layers of cast-in-place concrete

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