EP2821562A2 - Composite wood-concrete structure - Google Patents

Abstract

A timber component (1) for a wood-concrete composite construction (100), with a load-bearing substructure (10) and an adjacent composite superstructure (20) for surface bonding to concrete (30). According to the invention, it is provided that the composite superstructure (20) for receiving shear and transverse tensile forces between the timber component (1) and concrete (30) and for redistributing the thrust forces within the timber component (1) at least two, preferably exactly two, crosswise to each other arranged layers of at least two laterally spaced webs, strips, slats, boards (21) o. The like. Has and compared to the base (20) is completed flat

Description

The invention relates to a wooden component for a wood-concrete composite construction, with a supporting substructure and an adjacent composite superstructure for surface bonding with concrete. The invention further relates to a wood-concrete composite construction with at least one such timber component and at least one concrete component.

Wood-concrete composite structures have long been known from the prior art and consist of wooden elements or wooden components, which are shear-resistant connected to a adjacent to a composite surface of the timber component concrete component. Wood-concrete composite structures are used in the construction industry in particular, where the advantages of the building material wood should be combined with the advantages of the building material concrete. Such a construction is based on the basic idea of assigning the compressive forces to the wood in the composite cross section, above all the tensile forces and the concrete.

Wood-concrete composite construction can be used as a supporting and / or raumabschließendes component both in new construction as well as in the upgrading of existing wood or wood material constructions.

In the context of the present invention, the term timber component is to be understood as meaning all load-bearing and / or space-enclosing wooden constructions which can be combined with concrete to form a wood-composite construction. These can be both ceiling and wall-forming constructions.

In the ceiling formation include the so-called beam construction, consisting of a beam layer and possibly arranged thereon wooden formwork, and the so-called board stack construction from side by side arranged, nailed or pegged side boards are used.

In addition, so-called cross-plywood or cross-ply constructions are increasingly being used. These are cross-glued layers of boards arranged side by side, similar to the construction of conventional plywood panels. Due to their areal structure, such wooden components are suitable for both ceiling and wall-forming constructions.

In order to exploit the advantages of a wood-concrete composite construction, it must be ensured that a permanent connection exists between the timber component and the concrete component, so that both longitudinal and lateral forces can be absorbed by the composite element and the composite element under all load situations static unit is to be regarded.

To absorb shear forces between the concrete and wooden component, it is known from the prior art to provide in the composite surface of the wooden component recesses, preferably so-called cervical, which are filled with concrete or are in engagement with the concrete. In order to introduce the thrust forces, which run essentially parallel to the composite surface, into the wooden component, the recesses have, as abutments for the concrete, substantially flanks aligned transversely to the composite surface. In the context of the present invention, the term transverse means not only a flank orientation perpendicular to the composite surface, but also any inclined flank orientation different from 0 ° or 180 °.

In order to prevent lifting of the concrete slab due to the Extensitätsmoments arising in the region of the recess or to absorb transverse forces between wood and concrete component, various connection means are known from the prior art, which are firmly connected on the one hand with the concrete and on the other hand with the timber component. In addition to adhesive joints are mainly mechanical fasteners such as screws, dowels, Nails u. Like. For use. For example, in the distributed over the wooden component recesses long wood screws or dowels are screwed in, which protrude perpendicular to the composite surface over the wood cross-section and anchor-like with the concrete engaged. In addition to single screws and dowels, composite systems of crossed pairs of screws or dowels inclined at 45 ° to the composite surface are also known.

Furthermore, it is off DE 298 24 534 U1 a board stack element known between the slats sheets or squared timbers are arranged, which protrude as webs in the concrete slab. The bond between wood and concrete takes place via so-called transverse force anchors, which are inserted into recesses of the webs.

However, such fasteners are usually associated with very high manufacturing and material costs and also allow only a low degree of prefabrication. In particular, there is a risk that the connecting means projecting beyond the wooden component will be damaged when transporting a plurality of stacked wooden elements. Even walking the wooden elements on the site and laying the concrete reinforcement is hampered by the protruding fasteners.

Out DE 298 16 002 U1 is a composite construction is known in which the simultaneous absorption of shear and shear forces is achieved by a positive connection between concrete and wood. For this purpose, the wood-concrete composite construction in the area of the composite surface reinforced concrete strips, glued profiled slats or milled depressions, which extend transversely to the clamping direction of the composite structure. The strips or recesses have in cross section a conical shape and thus an undercut, which serves to accommodate Querzugkräften.

All of the aforementioned connecting means have in common that they produce a rigid bond between the concrete and the wooden component. As a result, the webs, strips, recesses and / or connecting means for Anchorage of the concrete or fixation of the strips and / or webs according to the composite stress, ie according to the course of the shear forces on the composite structure, with varying distances from each other, otherwise fail the utilization ratio of the composite structure in a configuration with a constant distance significantly lower. Accordingly, the arrangement of the recesses and composites must be recalculated for each concrete composite construction. In addition, the rigid composite construction in the range of larger spans borders on their performance, since the power transmission potential in the region of the recesses is locally limited.

In order to allow at least an equidistant arrangement of the profile strip connecting means regardless of the course of the longitudinal thrust forces proposes DE102 54 043 B4 a wood-concrete composite structure, in which profiled for producing a non-positive composite wood ribs with a negative edge slope, ie with an undercut, are arranged on the composite surface to the concrete, but in contrast to the profiled slats in DE 298 16 002 U1 parallel to the main support direction of the composite cross section. For fixing the projecting into the concrete ribs on the wooden component pin or screw-shaped connection means or surface gluing are provided. Due to the multi-part construction of the manufacturing and manufacturing effort but also here correspondingly expensive. In addition, these as well as the aforementioned constructions allow only a uniaxial load transfer within the clamping level of the composite.

Object of the present invention is therefore to improve wood components and wood-concrete composite structures of the type mentioned in that a flat, durable and sustainable bond between concrete and wood regardless of the actual course of longitudinal thrust forces and beyond a multi-axis load transfer can be achieved , Furthermore, the cost and time compared to the known wood-concrete composite structures should be further reduced while achieving a high degree of prefabrication.

The object is achieved by a wooden component with the features of claim 1 and a wood-concrete composite structure with the features of claim 8. Advantageous embodiments of the invention are the subject of the dependent claims.

According to the invention, the timber component with load-bearing substructure and adjacent composite superstructure is characterized in that the composite superstructure for receiving shear and transverse tensile forces between the timber component and concrete and for redistributing the thrust forces within the timber component at least two, preferably exactly two, crosswise superimposed layers each has at least two laterally spaced webs, strips, slats, boards o. The like. And is closed to the base surface.

Under a crosswise arrangement is preferably a mutually perpendicular course of the webs, strips, slats, boards o. The like. To understand in mutually adjacent layers. Also conceivable, however, are orientations of adjacent layers deviating from 90 °. Furthermore, there are the webs, strips, slats, boards o. The like. Preferably made of wood and / or a wood material.

In accordance with the invention, it has been recognized that cavities with undercuts, which can be filled with concrete, are formed within the composite superstructure by the construction method described above between the crosswise arranged layers of spaced webs, strips, slats, boards or the like Curing positively engages the timber component. As a result, can be effectively removed by the thus created interlocking of the concrete with the upper board layer resulting from the composite effect between concrete and wooden component transverse tensile forces.

Accordingly, shear forces on the lateral flanks of the individual webs, strips, slats, boards o. The like. Included. The transverse, preferably perpendicular, aligned to the composite flanks serve as an abutment for the concrete. A particular advantage of the construction of the wood component according to the invention lies in the fact that the crosswise arrangement of at least two layers, in contrast to the known from the prior art constructions effectively a biaxial load transfer of shear forces within the wood-concrete composite construction is effected. Decisive for this is that the construction of at least two crosswise arranged web, ingot, slat or board layers in two mutually perpendicular directions flanks or flank sections, in which consequently the shear forces occurring parallel to the composite surface can be accommodated in two mutually perpendicular directions ,

For reasons of weight, the penetration depth of the wooden component with concrete in the direction perpendicular to the composite surface is just chosen so great that a sufficient bond between wood and concrete is ensured. The concrete is therefore only in direct engagement with the composite superstructure of the timber component. In order to limit the depth of penetration or to prevent the concrete from penetrating into the substructure, the composite superstructure according to the invention is completely flat with respect to the substructure.

Particularly preferably, the composite superstructure on exactly two mutually crosswise arranged layers, which are completed flat against the base. The cavity formed by two layers sufficient on the one hand to ensure adequate anchoring of the concrete with the composite superstructure and a biaxial load transfer, and on the other hand serves to limit the weight of the finished wood-concrete composite construction due to the limited concrete receiving volume in the composite superstructure ,

According to the invention, it was further recognized that by the spaced arrangement of the webs, strips, slats, boards o. The like. On the gap in combination with the wood or wood material material properties of the webs, strips, slats, boards o. The like sufficient compliance or deformability of the composite is given in the direction of the longitudinal thrust forces. It was recognized that wood components in the direction perpendicular to the wood fiber have a much lower modulus of elasticity as in parallel direction to the wood fiber. A smaller modulus of elasticity means that the wood component offers little resistance to its elastic deformation. Depending on the type of wood, the modulus of elasticity in the vertical direction can amount to only a few percent of the modulus of elasticity in a parallel direction. For example, the modulus of elasticity in the vertical direction may be 300 N / mm ² and in the vertical direction 10,000 N / mm ² .

Such a low modulus of elasticity in the direction perpendicular to the wood fiber and the flexibility associated therewith result in a certain longitudinal displaceability between the concrete and the wooden component, which results in an effective redistribution of the thrust forces within the timber component. In particular, a failure of the connecting means with which the webs, strips, slats and boards are connected to each other and to the composite substructure can be avoided, since the redistribution of the shear forces the load capacity of the timber component is used in otherwise less stressed areas with. Due to the redistribution, furthermore, the arrangement of the individual webs, strips, slats, boards or the like can take place independently of the specific course of the longitudinal thrust forces. In particular, the boards or the like can be arranged substantially equidistantly. Due to the resilience of all composite materials and boards o. The like. Experiencing approximately the same stress, and the computational effort to determine the exact number and distribution of the individual boards o. The like. In composite superstructure in a concrete composite construction is significantly reduced. The wood component is therefore universally applicable for various applications and less prone to error in its manufacture. Since, in particular, a differentiated spacing arrangement of the boards or the like and composite means over the length of the carrier element is eliminated, a total of a fast and systematic production sequence can thus be ensured.

Since the required for redistribution of the longitudinal thrust forces compliance of the wood is given in the direction perpendicular to the wood fiber, is the longitudinal axes of the webs, strips, slats, boards o. The like. Conveniently selected in parallel to the wood fiber direction.

Furthermore, the flexibility and thus the property for redistributing the longitudinal thrust forces can be influenced by a suitable choice of the wood material or type of wood. Advantageously, the composite superstructure and substructure can also be made of different types of wood, wood materials or wood-based materials. While for the substructure wood types, wood materials or wood-based materials high load capacity can be used, wood types, wood materials or wood-based materials with special, vorzugsswiese bidirectionally different elasticity properties are selected for the composite superstructure. In principle, however, other materials are also conceivable for the composite superstructure, for example metal or concrete or combinations of wood, wood-based material, metal and / or concrete.

Since no connecting means protrude beyond the composite surface in the wood component according to the invention, a transport of several stacked wooden components and a walking of the timber components on the site is also easily possible.

For the construction of the timber component according to the invention is according to a first advantageous embodiment of the invention, the use of so-called cross-laminated timber or cross laminated wood constructions. These are cross-laminated boards analogous to the production of a conventional plywood. Accordingly, it may be provided in an advantageous manner that the substructure is designed as cross laminated wood or cross laminated timber, and / or that the entire wood component is designed as cross laminated wood or cross laminated timber, wherein the formation of the composite superstructure, the boards in the at least two upper layers on a Side of the cross laminated wood or cross laminated timber, in particular with the omission of every other board, are arranged laterally spaced from each other.

In order to realize the inventively provided extensive conclusion between supporting substructure and adjacent composite superstructure, it is provided according to a further advantageous embodiment of the invention that the substructure on the composite superstructure facing side has a closed surface and / or that between the substructure and composite superstructure, a flat separating layer, preferably made of wood, is provided. The closed surface or separating layer preferably serves as a formwork during the concreting process. To produce the closed surface or a separating layer, it may be provided, for example, in the cross laminated timber constructions used advantageously that only in the two upper cross layers each second board is omitted, whereas the other layers formed over the entire surface of directly adjacent boards are. It is also conceivable additionally or alternatively, a separate separation layer, for example, of a thin sheet or a thin film.

According to a further advantageous embodiment of the invention, the webs, strips, slats, boards o. The like. Glued in the composite superstructure and / or nailed and / or screwed. This can affect both the connection of the layers with each other and the connection between composite superstructure and substructure. Particularly preferred are screwing or nailing, since these types of connections always accompanied by a certain flexibility compared to gluing or gluing, so that the already given by the wood properties compliance and the associated redistribution of shear forces can be increased. It is also conceivable that the redistribution of the thrust forces is effected by the elasticity properties or flexibility of the compound alone or for the most part.

Furthermore, it can be provided according to a further advantageous embodiment of the invention that in the longitudinal direction of the webs, strips, slats, boards o. The like. At least every 50 cm, in particular at least every 40 cm, screw and / or nail connections are provided. Particularly advantageously, the invention allows an arrangement of the connecting means in substantially equal distances, regardless of the specific course of the longitudinal thrust forces.

Furthermore, the webs, strips, slats, boards o. The like. In the composite superstructure preferably a height in the range of 5 mm to 50 mm, in particular from 10 mm to 40 mm, and / or a width of 40 mm to 200 mm, in particular from 60 mm to 160 mm.

Accordingly, in a further advantageous embodiment of the invention, the distance between the webs, strips, slats, boards or the like in the composite superstructure between 0.5 times to 5 times, in particular 1 to 2 times, their width.

Of course, it is also conceivable that the boards of a single layer have different widths and / or different distances from each other. It is also conceivable that the boards of different layers have different heights.

An independent aspect of the invention relates to a wood-concrete composite construction with at least one concrete component and at least one timber component, in particular with at least one wooden component of the type described above, wherein the concrete component is engaged with at least one composite superstructure of the timber component, which is suitable for receiving thrust and Querzugkräften between wood component and concrete and redistributing the shear forces within the timber component at least two, preferably exactly two, crosswise arranged layers of at least two laterally spaced webs, strips, slats, boards o. The like., And against a supporting substructure Wooden component is completed flat.

Other objects, advantages, features and applications of the present invention will become apparent from the following description of an embodiment with reference to the drawings. All described and / or illustrated features alone or in any meaningful combination form the subject matter of the present invention, also independent of their summary in the claims or their dependency.

Fig. 1

perspektivische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen Holzbauteils für eine Holz-Beton-Verbundkonstruktion,

Fig. 2

Querschnitt durch ein Ausführungsbeispiel einer erfindungsgemäßen Holz-Beton-Verbundkonstruktion mit einem Holzbauteil gemäß Fig. 1, und

Fig. 3

Längsschnitt durch die Holz-Beton-Verbundkonstruktion gemäß Fig. 2.

Show it:

Fig. 1

perspective view of an embodiment of a wood component according to the invention for a wood-concrete composite construction,

Fig. 2

Cross section through an embodiment of a wood-concrete composite construction according to the invention with a timber component according to Fig. 1 , and

Fig. 3

Longitudinal section through the wood-concrete composite construction according to Fig. 2 ,

Fig. 1 shows a possible embodiment of a timber component 1 according to the invention for a wood-concrete composite construction, with a supporting base 10 and an adjacent composite superstructure 20 for surface bonding with concrete. While in Fig. 1 the sake of clarity no concrete is, the show Fig. 2 and 3 a possible embodiment of a finished wood-concrete composite construction 100 with a timber component 1 according to Fig. 1 and a concrete component 30, which is engaged with the composite superstructure 20 of the timber component 1 and is connected to this area.

According to the invention, the composite superstructure 20 for receiving longitudinal thrust and transverse tensile forces between the timber component 1 and concrete 30 and for redistributing the thrust forces within the timber component 1 at least two, in the present embodiment exactly two, crosswise superimposed layers of a plurality of laterally spaced apart boards 21st on.

The cavity formed by the two layers between the boards on the one hand sufficient to ensure a sufficient anchorage of the concrete 30 with the composite superstructure 20 and a biaxial load transfer, and on the other hand serves to the weight of the finished wood-concrete composite structure 100 due to the limited Concrete receiving volume in the composite superstructure 20 limit. To invade of the concrete 30 in the substructure 10 or to limit the penetration depth of the timber component 1 with concrete 30, the composite superstructure 20 according to the invention over the base 10 is completed flat.

The entire structure of the timber component 1 according to the embodiments of Fig. 1 to 3 is based on the so-called cross laminated timber construction, ie a wooden structure with crosswise arranged layers of wooden boards 11, 21 analogous to the production of a conventional plywood.

To form recesses 2 and corresponding undercuts 6, the two upper board layers of the cross-ply wood are not arranged over the entire surface. Rather, the individual boards 21 are set to gap, so that form between the boards 21 and board layers cavities that can be filled with concrete 30. Due to the toothing of the concrete 30 produced with the upper board layer, the transverse tensile forces arising from the composite effect can be effectively removed. The other full-surface layers of directly adjacent boards 11 form the opposite of the composite superstructure 20 surface finished substructure 10th

In order to absorb shear forces between concrete 30 and wooden component 1, the lateral flanks 5 of the boards 21 aligned substantially transversely to the composite surface 4 serve in the composite superstructure 20. A particular advantage of the construction of the timber component according to the invention lies in the fact that at least two are provided by the crosswise arrangement Board layers is effectively effected a biaxial load transfer of shear forces within the wood-concrete composite structure 100.

As a result, therefore, can be achieved with the timber component 1 according to the invention advantageously a combination effect for receiving longitudinal thrust and Querzugskräften.

Based on the realization that wood components in the direction perpendicular to the wood fiber have a significantly lower modulus of elasticity than in the direction parallel to the wood fiber, is by in the Fig. 1 to 3 shown Ausführungsbespiel a wooden component 1 according to the invention also achieves effective redistribution of shear forces within the timber member 1 and thus co-exhaust the carrying capacity of the timber member 1 in otherwise less stressed areas. In particular, a failure of the connecting means, with which the boards 21 are connected to each other and to the substructure 20, can be avoided. Due to the redistribution, furthermore, the arrangement of the individual boards 21 can take place independently of the specific course of the longitudinal thrust forces. In particular, the boards 21 can be arranged at substantially equal intervals. Due to the resilience of all composite means and boards 21, which experience approximately the same stress, the computational effort to determine the exact number and distribution of the individual boards 21 is also significantly reduced in a concrete composite construction. The wooden component 1 is thus universally applicable for various applications and less prone to error in its production. In particular, since a differentiated spacing arrangement of the boards 21 and composite means over the length of the support element is eliminated, thus a total of a fast and systematic production process can be ensured. Since the desired compliance of the wood is given in the direction perpendicular to the wood fiber, the longitudinal axes of the boards 21 are selected parallel to the wood fiber direction.

According to the present embodiment Fig. 1 to 3 the individual boards 21 and board layers of composite superstructure 20 are screwed together. Conceivable, however, are other connecting means such as, for example, nailing, bonding and / or gluing. Bolting or nailing in comparison to bonding or gluing the advantage that they are always associated with a certain flexibility, so that the already given by the wood properties compliance and the associated redistribution of shear forces is supported supportive. The individual boards 11 of the substructure 10 are glued together in the present embodiment.

LIST OF REFERENCE NUMBERS

1

timber member

2

recess

4

composite surface

5

flank

6

undercut

10

substructure

11

Board in the substructure

20

composite superstructure

21

Board in composite superstructure

30

Concrete component / concrete

100

Wood-concrete composite structure

Claims (8)

Timber component (1) for a wood-concrete composite structure (100), comprising a supporting substructure (10) and an adjacent composite superstructure (20) for surface bonding to concrete (30), characterized in that the composite superstructure (20) for receiving Push and Querzugkräften between wood component (1) and concrete (30) and for redistribution of shear forces within the timber component (1) at least two, preferably exactly two, crosswise arranged layers of at least two laterally spaced ridges, strips, slats, boards (21) o. The like. Has and compared to the substructure (20) is completed flat. Wood component (1) according to claim 1, characterized in that the substructure (10) is designed as cross laminated wood or cross laminated timber and / or that the entire wooden component (1) is designed as cross laminated wood or cross laminated timber, wherein for forming the composite superstructure (20). the boards (21) in the at least two upper layers on one side of the cross laminated wood or cross laminated timber, in particular with the omission of every other board, laterally spaced from each other are arranged. Wood component (1) according to claim 1 or 2, characterized in that the substructure (10) on the composite superstructure (20) facing side has a closed surface and / or that between substructure (10) and composite superstructure (20) has a two-dimensional release layer ( 40), preferably made of wood, is provided. Wood component (1) according to one of the preceding claims, characterized in that the webs, strips, slats, boards (21) o. The like. In the composite superstructure (20) are glued and / or nailed and / or screwed. Wood component (1) according to claim 4, characterized in that in the longitudinal direction of the webs, strips, slats, boards (21) o. The like. At least all 50 cm, in particular at least every 40 cm, screw and / or nail connections are provided. Wood component (1) according to any one of the preceding claims, characterized in that the webs, strips, slats, boards (21) o. The like. In the composite superstructure (20) has a height in the range of 5 mm to 50 mm, in particular from 10 mm 40 mm, and / or a width of 40 mm to 200 mm, in particular from 60 mm to 160 mm. Wood component (1) according to one of the preceding claims, characterized in that the distance between the webs, strips, slats, boards (21) o. The like. In the composite superstructure (20) between 0.5 times to 5 times, in particular 1-fold to 2-fold, their width is. Wood-concrete composite construction (100) with at least one concrete component (30) and at least one timber component (1), in particular at least one timber component (1) according to one of the preceding claims, wherein the concrete component (30) is provided with at least one composite superstructure (20) of the Wooden component (1) is engaged, which for receiving shear and transverse tensile forces between the timber component (1) and concrete (30) and for redistributing the thrust forces within the timber component (1) at least two, preferably exactly two, crosswise arranged layers of each has at least two laterally spaced webs, strips, slats, boards (21) o. The like. And over a supporting substructure (20) of the timber component (1) is completed flat.

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