CA3091031A1

CA3091031A1 - Method for producing composite floors, and composite floor

Info

Publication number: CA3091031A1
Application number: CA3091031A
Authority: CA
Inventors: Klaus Engelhart
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-02-13
Filing date: 2019-02-12
Publication date: 2019-08-22
Also published as: AT520303B1; CN111712606A; EP3752688A1; EP3752688B1; WO2019157544A1; AT520303A4; CN111712606B

Abstract

The invention relates to a method for producing composite floors, in which timber elements (1) are placed directly next to one another on supports and connected to one another, and a composite floor is produced by applying a concrete layer (4). A low flexure is achieved according to the invention in that the connecting elements (2) are fastened to the timber elements (1) and then reinforcing elements (3) are placed on the connecting elements (3), wherein the reinforcing elements (2) are connected to the connecting elements (2) in a play-free manner.

Description

Method for producing composite floors, and composite floor The invention relates to a method for producing composite floors in which timber elements are placed directly next to each other on supports and connected to one another, wherein a composite floor is produced by applying a layer of concrete.
The present invention also relates to a composite floor, having several timber elements arranged side by side, on which connecting elements are mounted, and having a concrete layer which is arranged on the timber elements and which is provided with reinforcing elements.
Timber elements in the above sense are to include wooden beams, which can be constructed in one piece or glued from boards, but also plate-shaped elements, which for example can be constructed in several layers. In any case, a single timber element typically spans the area between two supports and there are usually several timber elements arranged next to each other.
It is already known to design building floors as so-called composite floors, where typically a lower section is made of wood and an overlying section of concrete. One advantage of such composite floors is that the wooden layer serves as a lost formwork and thus the production is simplified. The wooden layer represents a structural advantage for the space below the floor. In terms of strength and stiffness, composite floors make use of the high tensile strength of wood and the fact that the entire cross-section of the wood can take up tensile forces, which is in contrast to a pure concrete floor, where tensile forces can essentially only be taken up by the reinforcement. With a composite floor, the wood is essentially stressed in tension and the concrete is essentially stressed in compression, so that the advantageous properties of these building materials are optimally used.
DE 198 18 525 A discloses a wood-concrete composite element in which a wooden layer is composed of a plurality of squared lumber members, which is connected to a concrete layer via connecting elements. In addition, reinforcing elements are provided within the concrete layer. These are necessary if only to prevent cracks in the concrete layer caused by shrinkage during curing. The advantages described above can be achieved with such a composite floor. However, the strength and especially the stiffness of such a composite floor is insufficient for some applications. Therefore, in some cases a too large thickness of the material layers is necessary to meet the given requirements.
Similar variants are also known from WO 2009/150589 A, EP 0 352 566 A and DE
102 54 043 A.
Date Recue/Date Received 2020-08-12

- 2 -A particular disadvantage of the known solutions is that the wood layer, due to the inadequate bonding with the concrete layer, also leads to a compressive load on the wood, which can typically be absorbed only insufficiently compared to a tensile load.
It is the object of the present invention to avoid these disadvantages and to provide a method for producing a composite floor and a special composite floor so that the strength and stiffness of the composite floor can be increased under otherwise identical conditions.
According to the invention, this is achieved by a method in which connecting elements are fixed to the timber elements and then reinforcing elements are placed on the connecting elements, wherein the reinforcing elements are connected to the connecting elements without play.
The composite floor according to the invention is characterized in that the reinforcing elements are connected to the connecting elements without play, regardless of the concrete layer.
The essential advantage of the present invention is that the transmission of shear forces between wood and concrete is not only carried out by the connecting elements, as is the case with the prior art, but also by the reinforcing elements, with the connecting elements acting as intermediate members. An essential aspect of the invention is that the connecting elements and the reinforcing elements are directly connected to each other without any possibility of relative movement, so that the transmission of forces starts to take effect at a minimal deformation of the composite floor. In the case of an indirect connection via the concrete layer as in the prior art, a limited relative movement between wood and concrete can take place without significant shear forces being transmitted. As a result, at the beginning of a load, the wood layer and the concrete layer can deform without significant forces being transmitted between them, resulting not only in reduced strength but also in increased deflection under load.
In the solution according to the invention, such a transfer of shear forces at the boundary between concrete and wood takes place at minimal deflection and therefore at minimal load. In principle, the composite floor can therefore be treated like a homogeneous beam, except that the modulus of elasticity can vary in the direction of thickness.
It is also an important aspect of the invention that the forces are transferred from the wood layer via the connecting elements to the concrete layer over a large area.
This allows the materials to be used in the best possible way to optimize the load-bearing capacity. The wood layer is loaded exclusively or at least to a large extent Date Recue/Date Received 2020-08-12

- 3 -in tension, wherein the entire cross-section is available to absorb the load.
An unfavorable compressive stress is thus avoided.
It has proven to be particularly advantageous if one connecting element is used in each case to connect two adjacent timber elements. It is in itself possible to use connecting elements only to connect one timber element with the reinforcement.

However, the double use of connecting elements is particularly advantageous.
In this context, it is particularly advantageous if a connecting element is inserted into a groove formed by two adjacent timber elements. In this way a force transmission between a connecting element and the adjacent timber elements is not only effected by the nails or staples with which the connection is made, but also by the flanks of the groove and the adjacent connecting element in a positive locking manner.
It is particularly preferred if the reinforcing elements are inserted in receiving grooves of the connecting elements. In this way, the connection can be made in a simple manner, especially on the construction site, by placing the reinforcing elements, typically in the form of standard structural steel meshes, on the connecting elements and hammering them into the grooves. It is helpful if the receiving grooves of adjacent connecting elements are aligned accordingly so that only minimal deformation of the reinforcing steel meshes is required to make the connection.
A particularly stiff structure of the composite floor can be achieved by connecting one reinforcing element with several connecting elements.
Especially when using integral solid wooden beams as timber elements, slight height deviations in the central area of the floor may occur after placement because the individual beams are not completely straight. A completely level floor soffit can be ensured in particular by aligning the timber elements in the height direction before fixing the connecting elements. This can be carried out, for example, by placing individual beams that project downwards underneath in the middle to push them slightly upwards.
Preferably, the timber elements are provided with a hydrophobic protective layer before the concrete layer is applied. This allows a significant reduction in the water absorption of the timber elements during production, which reduces the risk of undesirable deformations.
It is preferable to carry out the construction of the composite floor to a large extent on the construction site, i.e. first the timber elements are placed on the supports, then the connecting elements are attached and then the reinforcing elements are Date Recue/Date Received 2020-08-12

- 4 -connected to the connecting elements, after which the concrete layer is applied.
However, it is also possible to carry out parts of these activities in a factory and to deliver the composite floor to the construction site semi-finished or finished. For example, several timber elements can already be connected to connecting elements to form larger units when they are delivered to the construction site.
Optionally, reinforcing elements or even the concrete layer may already have been applied. In this way, the work on the construction site can be simplified and accelerated.
It has proved to be particularly advantageous if the timber elements are designed as solid wooden beams. This allows a particularly cost-effective solution to be achieved.
An embodiment variant of the invention which is particularly advantageous in terms of design is characterized in that the timber elements are beveled on their upper side so that two adjacent timber elements form a V-shaped groove extending in the longitudinal direction. In this way a non-positive and positive connection with the connecting elements can be achieved. This is particularly advantageous if the connecting elements are designed as V-shaped profiles.
A statically particularly advantageous solution is to arrange the connecting elements parallel to the timber elements. This allows shear forces to be transmitted to the concrete layer over the entire length of the timber elements.
According to a preferred embodiment variant of the invention, the connecting elements are designed as profiles with longitudinal webs in which receiving grooves are provided. In addition to an optimal transmission of force, the necessary distance of the reinforcing elements from the boundary of the concrete layer can be ensured in this way. The webs extending in the longitudinal direction comprise recesses between the receiving grooves in a particularly preferred manner.
This additionally improves the frictional connection within the concrete.
Preferably, the reinforcing elements are designed as structural steel meshes.
This allows the reinforcement to be produced easily and in all directions.
A particularly advantageous embodiment variant of the invention provides that milled grooves are provided in the timber elements on a surface facing the concrete layer. In this way, the shear forces between the timber elements and the concrete layer are not only transmitted via the connecting elements, but also directly at the boundary surface, so that an additional increase in strength and bending stiffness can be achieved. It is particularly advantageous if the milled grooves are wedge-shaped. The wedges are provided in particular in the end areas and in such a way that the floor rises towards the middle in the position of use and a support surface Date Recue/Date Received 2020-08-12

- 5 -is provided on the side facing the end to absorb the shear forces from the concrete layer when the composite floor is loaded. In particular, this provides increased safety in the event of fire, if the connecting elements should fail due to excessive heating.
The milled grooves described above also provide additional safety in the event of fire, should the connecting elements begin to fail due to extreme heating after prolonged exposure to fire, as the shear forces can still be transmitted then.
A sealing element is preferably provided between two adjacent timber elements.

This can prevent concrete water from seeping through the gap between two timber elements during production and causing unsightly discoloration on the soffit.
As a sealing element, for example, a bead of fire-resistant intumescent acrylic is applied to the bottom of the V-shaped groove.
The fire resistance can be increased in particular by providing a fire protection element between two adjacent timber elements. This is particularly formed in an intumescent manner, i.e. it foams up when heated and prevents fire from burning into the gap between two timber elements and prematurely destroying the wooden beams or exposing the connecting elements to heating that leads to failure.
In the following, the present invention will be explained in more detail by means of the exemplary embodiments shown in the figures, wherein:
Fig. 1 schematically shows a first embodiment variant of a composite floor according to the invention in an oblique view with partially broken off components;
Fig. 2 shows a detail of the embodiment variant of Fig. 1;
Fig. 3 shows a further detail with a partially depicted concrete layer;
Fig. 4 shows a top view of the composite floor of Fig. 1 to Fig. 3;
Fig. 5 schematically shows a composite floor of Fig. 1 to Fig. 4, in accordance with the invention, in an oblique view with supports;
Fig. 6 shows another detail;
Fig. 7 shows an oblique view of a second embodiment variant from below;
Fig. 8 shows the embodiment variant of Fig. 7 in a frontal view; and Fig. 9 shows a detail of another embodiment variant.
Date Recue/Date Received 2020-08-12

- 6 -Fig. 1 shows a section of a composite floor according to the invention with partially omitted components.
The composite floor consists of several timber elements 1, which are designed as wooden beams arranged parallel to each other. In each case between two timber elements 1, a connecting element 2 is provided on the upper side, which is designed as a profile extending parallel to the timber elements 1.
Reinforcing elements 3 in the form of structural steel meshes are connected to the connecting elements 2 in such a way that the reinforcing elements 3 extend parallel to the timber elements 1 just above them.
As can be seen in Fig. 3, a concrete layer 4 is provided above the timber elements 1, surrounding the reinforcing elements 3. In the illustration of Fig. 3, this layer is broken away at the front in order to be able to show the other components.
The timber elements 1 have an essentially rectangular cross-section, wherein the upper two corners are beveled so that two adjacent timber elements 1 each form a V-shaped groove 5 with a triangular cross-section. A V-shaped profile with legs 6a, 6b is fitted into this groove to form a connecting element 2. At each end of the profile, a web 7 is formed in each case, which has sections 7a projecting upwards alternately in the longitudinal direction and horizontally projecting fastening sections 7b in between.
The connecting elements 2 are connected to the timber elements 1 by nails 8, which are driven diagonally into the V-shaped groove 5 on one side and vertically through the fastening sections 7b into the timber elements 1 on the other side.
Alternatively, screws or clamps are also possible. In addition to this, a gluing of the fastening elements 2 to the timber elements 1 can be provided.
In an alternative embodiment variant not shown here, a connecting element 2 can also be placed flat on top of a timber element 1 to ensure the intimate connection of the timber element 1 with the concrete layer.
On the upper side of the upwardly projecting sections 7a, receiving grooves 9 are provided in which the reinforcing elements 3 are clamped so that they are connected to the connecting elements 2 and thus to the timber elements 1 without play even before the concrete is placed. Essential for the invention is that due to the close fit there is always a frictional and positive fit between the reinforcing elements 3 and the connecting elements 2, so that a direct transmission of force is guaranteed.
Date Recue/Date Received 2020-08-12

- 7 -The reinforcing elements are typically driven into the receiving grooves 9 during production.
The timber elements 1 have milled grooves 10, which are incorporated in end areas 12 of the timber elements 1 on the upper sides 11 facing the concrete layer 4.
The milled grooves 10 are wedge-shaped and have a bottom 13 rising to the middle of the timber elements 1, so that a supporting surface 14 is formed in the direction of the ends 5, to which shear forces from the concrete layer 4 can be transferred.
In this way, the concrete layer 4 can also support itself on the timber elements 1 when loaded via the sections protruding into the milled grooves 10 and thus transfer additional shear forces. These shear forces act outwards so that the supporting surfaces 14 can effectively transfer them.
Typically, the composite floor according to the invention is supported at its ends on supports 15 only shown in Fig. 5.
In the embodiment variants shown in Fig. 7 and Fig. 8, a fire protection element 17 in the form of a spring is inserted between two adjacent timber elements 1, which prevents a fire from spreading rapidly upwards from the soffit 16 between the two timber elements 1. Preferably, the fire protection element 17 has an intumescent design.
Alternatively or in addition, a sealing element 18 can be provided in the area of the bottom of the groove 5, which prevents concrete water from seeping down between the two timber elements 1 when the concrete is applied and impairs the soffit 16 by discoloration. This sealing element 18 can also have an intumescent section to provide additional fire protection. Alternatively, the sealing element 18 can be arranged in the form of a bead of sealing material at the bottom of the groove 5.
The embodiment variant shown in Fig. 9 differs only in the design of the connecting elements 2, which is why only one is shown. Only the sections 7a protruding upwards are designed, but not horizontally protruding fastening sections.
Thus, there are recesses 19 between the upwardly projecting sections 7a and thus also between the receiving grooves 9, which ensure a continuous frictional connection in the concrete, also transversely to the connecting elements 2.
The composite floor can be made by placing the timber elements 1 individually on supports 15 and then applying the connecting elements 2 and the reinforcing elements 3, after which the concrete layer 4 is made. However, prefabrication can also be carried out so that several interconnected timber elements 1 are already placed on the supports 15 and then the connecting elements 2 and the reinforcing Date Recue/Date Received 2020-08-12

- 8 -elements 3 are already installed. The concrete layer 4 may also already have been applied and cured.
Date Recue/Date Received 2020-08-12

Claims

C LAI M S

1. Method for producing composite floors, in which timber elements (1) are placed directly next to one another on supports and are connected to one another, wherein a composite floor is produced by applying a concrete layer (4), characterized in that connecting elements (2) are fastened to the timber elements (1) and then reinforcing elements (3) are placed on the connecting elements (2), wherein the reinforcing elements (3) are connected to the connecting elements (2) without play.

2. Method according to claim 1, characterized in that a connecting element (2) is used in each case for connecting two adjacent timber elements (1).

3. Method according to claim 2, characterized in that a connecting element (2) is inserted into a groove (5) which is formed between two adjacent timber elements (1).

4. Method according to one of claims 1 to 3, characterized in that the reinforcing elements (3) are inserted into receiving grooves (9) of the connecting elements (2).

5. Method according to one of claims 1 to 4, characterized in that a reinforcing element (3) is connected to a plurality of connecting elements (2).

6. Method according to one of claims 1 to 5, characterized in that the timber elements (1) are aligned in the height direction before the fastening of the connecting elements (2).

7. Method according to one of claims 1 to 6, characterized in that the connecting elements (2) are glued to the timber elements (1).

8. Method according to one of claims 1 to 7, characterized in that the timber elements (1) are provided with a hydrophobic protective layer before the concrete layer (4) is applied.

9. Method according to one of claims 1 to 8, characterized in that the connecting elements (2) are attached to the timber elements (1) after being placed on the supports (15).

10. Method according to one of claims 1 to 9, characterized in that a sealing element is inserted between the timber elements (1).

11. Method according to one of claims 1 to 10, characterized in that a flre protection element is inserted between the timber elements (1).
Date Recue/Date Received 2020-08-12

12. Composite floor, having several timber elements (1) arranged next to each other, having a concrete layer which is arranged on the timber elements (1) and which is provided with reinforcing elements (3), characterized in that connecting elements (2) are mounted on the timber elements (1), and in that the reinforcing elements (3) are connected to the connecting elements (2) without play independently of the concrete layer (4).

13. Composite floor according to claim 12, characterized in that several timber elements (1) are connected to each other by at least one connecting element (2).

14. Composite floor according to one of claims 12 or 13, characterized in that the timber elements (1) are formed as solid wooden beams.

15. Composite floor according to one of claims 12 to 14, characterized in that the timber elements (1) are beveled on their upper side so that in each case two adjacent timber elements (1) form a V-shaped groove (6) extending in the longitudinal direction.

16. Composite floor according to claim 15, characterized in that the connecting elements (2) are designed as V-shaped profiles.

17. Composite floor according to one of claims 12 to 16, characterized in that the connecting elements (2) are arranged parallel to the timber elements (1).

18. Composite floor according to one of the claims 12 to 17, characterized in that the connecting elements (2) are designed as profiles which have webs (7) extending in the longitudinal direction in which receiving grooves (9) are provided.

19. Composite floor according to claim 18, characterized in that the webs (7) extending in the longitudinal direction have recesses (19) between the receiving grooves (9).

20. Composite floor according to one of claims 12 to 19, characterized in that the reinforcing elements (3) are designed as structural steel meshes.

21. Composite floor according to one of claims 12 to 20, characterized in that milled grooves (10) are provided in the timber elements (1) on a surface (11) facing the concrete layer (4).

22. Composite floor according to claim 21, characterized in that the milled grooves (10) are wedge-shaped.
Date Recue/Date Received 2020-08-12

23. Composite floor according to one of claims 21 to 22, characterized in that the milled grooves (10) are provided in each case in end regions (12) of the timber elements (1).

24. Composite floor according to one of claims 12 to 23, characterized in that the connecting elements (2) are glued to the timber elements (1).

25. Composite floor according to one of claims 12 to 24, characterized in that the connecting elements (2) are connected to the timber elements (1) by nails, staples or screws.

26. Composite floor according to one of claims 12 to 25, characterized in that the timber elements (1) are provided with a hydrophobic protective layer.

27. Composite floor according to one of claims 12 to 26, characterized in that a sealing element (18) is provided between two adjacent timber elements (1).

28. Composite floor according to one of claims 12 to 27, characterized in that a fire protection element (17) is provided between two adjacent timber elements (1).

Ba Date Recue/Date Received 2020-08-12