Method for producing a connection of a flat wood concrete composite element with at least one part of a wood structure

Abstract

The present invention is based on the objective of providing a method for producing a connection between a planar wood-concrete composite element and at least a part of a load-bearing wood structure, in which the connection can be achieved in a planar manner. This objective is achieved according to the invention by a method for producing a connection between a planar wood-concrete composite element and at least a part of a preferably also load-bearing wood structure, which comprises the following steps: a) providing the prefabricated, planar wood-concrete composite element (4) with a first flush-mounted wood structure (8), b) applying an intermediate layer (12, 12a, 12b) to at least a part of the preferably also load-bearing wood structure (18) and / or at least a part of the flush-mounted wood structure (8), wherein the intermediate layer (12, 12a, 12b) either exhibits adhesive bonding forces through the action of temperature, i.e.,h) so-called adhesive effect, develops or consists entirely of cold-curing adhesive; c) forming a sandwich comprising at least the part of the preferably also load-bearing wooden structure (18), the intermediate layer (12, 12a, 12b) and the flush-mounted wooden structure (8); and d) connecting the at least part of the preferably also load-bearing wooden structure (18) with the flush-mounted wooden structure (8) by curing the adhesive. In this way, a comparatively simple and very large-area bond can be achieved between the flush-mounted wooden structure of the wood-concrete composite element and the wooden surface of the at least part of the wooden structure.

Description

[0001] The present invention relates to a method for producing a connection between a planar timber-concrete composite (HCV) element made of prefabricated individual parts and at least a part of a timber structure, in particular a load-bearing timber structure.

[0002] In the construction of new houses, industrial buildings, and in the renovation of existing buildings, there is a high demand for structurally sound connections between timber beams / frames and concrete elements and / or prefabricated timber / concrete composite elements. These composite elements are joined with the timber beams / frames to form so-called timber / concrete composite structures and are then used, for example, as walls, load-bearing ceilings, and / or (prefabricated) roof elements. Compared to pure timber construction, these timber / concrete composite structures have the advantage of being comparatively lightweight despite the concrete component and still possessing a sufficiently high thermal mass despite the timber content. Furthermore, such structures significantly improve the acoustic properties of a building and also offer good fire resistance.With their improved sound insulation properties, they also reduce noticeable floor vibrations and thus provide excellent structural rigidity for the building. Beyond these technical advantages, the exposed wooden beams also satisfy the aesthetic desires of the client.

[0003] Particular attention must be paid to the connection of timber / concrete composite elements to at least partially load-bearing timber structures, such as floor joists, ceiling joists, studs, and the like. The timber / concrete composite elements are generally delivered to the construction site pre-assembled. These elements are typically designed as flat panels with a surface area of ​​several square meters and therefore must be connected to the timber structure on-site. This connection is usually achieved by screwing or nailing. This places considerable demands on the structural integrity of these connections, which can only be guaranteed with appropriately robust metal fasteners.

[0004] Document WO2007 / 079739A2 discloses a method for producing a connection between a prefabricated planar timber-concrete composite element and at least a part of a preferably also load-bearing timber structure, comprising the following steps: a) Providing the prefabricated, planar wood-concrete composite element with a first flush-mounted wood structure; b) Applying an intermediate layer to at least a part of the preferably also load-bearing wood structure, wherein the intermediate layer consists essentially of adhesive and either develops adhesive bonding forces, i.e., so-called adhesive effect, through the action of temperature or consists entirely of cold-curing adhesive; c) Forming a sandwich consisting of at least the part of the preferably also load-bearing wood structure, the intermediate layer, and the flush-mounted wood structure; and d) Connecting the at least part of the preferably also load-bearing wood structure to the flush-mounted wood structure by curing the adhesive located in the intermediate layer.

[0005] The present invention is therefore based on the objective of providing a method for producing a connection between a planar wood-concrete composite element and at least a part of a load-bearing wood structure, in which the connection can be achieved in a planar manner.

[0006] This problem is solved according to the invention by a method, according to claim 1, for producing a connection between a prefabricated planar wood-concrete composite element and at least a part of a preferably also load-bearing wood structure, which comprises the following steps: a) Providing the prefabricated, planar wood-concrete composite element with a first flush-mounted wood structure; b) Applying an intermediate layer to at least a part of the preferably also load-bearing wood structure and / or at least a part of the flush-mounted wood structure, wherein the intermediate layer either develops adhesive bonding forces through the action of temperature, i.e., so-called adhesive effect, or consists entirely of cold-curing adhesive; c) Forming a sandwich comprising at least the part of the preferably also load-bearing wood structure, the intermediate layer, and the flush-mounted wood structure; and d) Connecting the at least part of the preferably also load-bearing wood structure to the flush-mounted wood structure by curing the adhesive.

[0007] In this way, a relatively simple and highly effective connection can be achieved between the flush-mounted wood structure of the timber-concrete composite element and the wood surface of at least part of the timber structure. Here, the term "at least part" is always used to refer to the preferably load-bearing timber structure, because, in the context of this application, it generally refers to larger, at least partially load-bearing timber structures, such as roof beams, floor joists, studs, and entire building skeletons of timber-framed buildings.

[0008] According to the present invention, it is provided that i) a metallic conductive structure with at least two electrical contacts is associated with the intermediate layer, wherein this metallic conductive structure may already have been integrated into the intermediate layer before the association; ii) the sandwich is formed, comprising at least the part of the preferably also statically load-bearing wooden structure, the intermediate layer and the flush-mounted wooden structure; iii) an electrical voltage is temporarily applied to the electrical contacts in order to induce a current flow with resistance heating through the metallic conductive structure to liquefy at least part of the adhesive present in the intermediate layer; and iv) the at least part of the preferably also statically load-bearing wooden structure is connected to the flush-mounted wooden structure by the curing of the adhesive.

[0009] In this way, all the advantages associated with the use of co-polyamide hot melt adhesive, including the favorable viscosity of the adhesive in its liquid state, can be achieved.

[0010] To favorably influence the wood-to-wood joint, it may be intended that at least part of the wood structure and / or the flush wood surface exhibits topological features such as grooves, notches, holes, or other surface-structuring elements. For example, it is also possible to leave the surfaces of the wood parts to be glued rough-sawn, so that the roughness created during sawing alone promotes the penetration of the adhesive, which is liquefied by the electric resistance heating. This, in turn, can positively influence the stability of the adhesive bond after the adhesive has cured. The joint can also be reinforced by metallic fasteners or components such as cams, screws, or dowels.

[0011] According to the present invention, the metallic conductive structure is embedded in the intermediate layer as thin filaments. The metallic conductive structure can thus be completely embedded in the intermediate layer (except for the externally projecting electrical connections), resulting in simple application of the intermediate layer as well as a uniform distribution of the heat generated by the resistance heating.

[0012] Alternatively or additionally, the metallic conductive structure can also be glued onto the intermediate layer, whereby a one-sided or a two-sided application to the adhesive layer can be provided.

[0013] Preferred embodiments of the present invention are explained in more detail with reference to a drawing. The drawing shows: Figure 1 schematically shows a cross-section through a timber / concrete composite element; Figure 2 schematically shows a top view of the timber / concrete composite element with an applied adhesive layer; Figure 3 schematically shows a longitudinal section through a timber / concrete composite element connected to a load-bearing timber structure; and Figure 4 schematically shows a cross-section of a timber / concrete composite element connected to a load-bearing timber structure according to Figure 3 .

[0014] Figure 1 The figure shows - without claiming to be to scale - a cross-section through a wood / concrete composite element 2, which can be produced in a concrete plant.

[0015] The wood / concrete composite element 2 is a planar load-bearing element that can have an area of ​​several square meters and a thickness of up to a few tens of centimeters. The wood / concrete composite element 2 comprises an inserted wood profile 4, here, for example, with a trapezoidal profile and dome-shaped topological structures 6, which is bonded to the liquid concrete during concreting and, after the liquid concrete has hardened, is ready for transport with a wood surface 8 flush with the concrete 10 surrounding this wood surface 8.

[0016] An adhesive layer 12, shown here as two adhesive strips 12a, 12b, can be applied to this wooden surface 8 either at the concrete plant or later on the construction site. Naturally, only one sufficiently wide strip can be used. The adhesive strips 12a, 12b are adhered to the wooden surface 8, for which adhesive patches and / or staples are suitable. Wire filaments 14a, 14b have also been applied to the adhesive strips 12a, 12b. During the subsequent assembly of the wood / concrete composite element 2 with a supporting structure, an electric current can flow through these filaments, causing them to heat up due to their corresponding electrical resistance. To facilitate the current flow, two electrical contacts 16a, 16b project beyond the dimensions of the wood / concrete composite element 2, to which an electrical voltage V+, V- can be connected.

[0017] For example, a co-polyamide hot melt adhesive can be used as the adhesive embedded in the adhesive strips 12a, 12b. After heating, these hot melt adhesives melt and then harden – possibly with the application of further heat via resistance heating (hot curing). In the present embodiment, a thickness of 2 mm is chosen for the adhesive strips 12a, 12b to bond the wood surface 8 to a wooden supporting structure. Depending on the application, however, the thickness can also be less or more. The adhesive strips 12a, 12b can also be made of cold-curing adhesive systems (e.g., 1-component, 2-component, and 3-component epoxy resin adhesives, polyurethane adhesives).

[0018] The Figure 3Figure 1 now shows a schematic representation of the formed sandwich of the wood surface 8 of the wood / concrete composite element 2 and the surface of a wooden support beam 18 intended as a load-bearing structure. The adhesive strips 12a, 12b are embedded between them. After the application of an electrical voltage to the filaments 14a, 14b, these strips first melt and then harden in their final state, thus bonding the wood surface 8 and the surface of the support beam 18 over a large area, resulting in a very stable and durable connection. The side view is shown in Figure 2. Figure 4 The topological design of the surface of the inserted wooden profile 4, surrounded by the concrete 10, is also very clearly visible.

Claims

1. Method for producing a connection between a premanufactured flat wood-concrete composite element and at least one part of a preferably also statically load-bearing wood structure, comprising the following steps: a) providing the premanufactured flat wood-concrete composite element (4) with a first surface-flush wood structure (8), b) applying an intermediate layer (12, 12a, 12b) to at least one part of the preferably also statically load-bearing wood structure (18) and / or at least one part of the surface-flush wood structure (8), wherein the intermediate layer (12, 12a, 12b) substantially consists of adhesive and either develops binding forces that are adhesive due to the effect of temperature, i.e. what is known as the adhesive effect, or entirely consists of colder-hardening adhesive, and wherein a metallic conductive structure (14a, 14b) in the form of thin filaments with at least two electric contacts (16a, 16b) is inlaid in the intermediate layer (12a, 12b) or is adhesively bonded to the intermediate layer (12a, 12b); c) forming a sandwich, consisting of at least the part of the preferably also statically load-bearing wood structure (18), the intermediate layer (12, 12a, 12b) and the surface-flush wood structure (8); and d) connecting the at least one part of the preferably also statically load-bearing wood structure (18) to the surface-flush wood structure (8) through the curing of the adhesive located in the intermediate layer, wherein an electrical voltage is temporarily applied to the electrical contacts, in order to induce a current flow with resistance heating through the metallically conductive structure (14a, 14b) for temporary liquefaction of at least one part of the adhesive that is present in the intermediate layer (12, 12a, 12b).

2. Method according to claim 1, characterised in that the cutout from the wood structure (18) and / or the surface-flush wood structure (8) have topological structures (6), such as grooves, notches, holes or other elements that structure the surface, on their surfaces.

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