EP3752688B1 - Method for producing composite floors, and composite floor - Google Patents

Description

The invention relates to a method for producing composite ceilings in which wooden elements are placed directly next to one another on supports and connected to one another, a composite ceiling is produced by applying a concrete layer and connecting elements are attached to the wooden elements and then reinforcing elements are placed on the connecting elements.

The present invention also relates to a composite ceiling, with several wooden elements arranged next to one another, on which connecting elements are attached, and with a concrete layer which is arranged on the wooden elements and which is provided with reinforcing elements, wherein connecting elements are attached to the wooden elements.

As wooden elements in the above sense, wooden beams are to be included which can be constructed in one piece or also glued from boards, but also plate-shaped elements which can be constructed in multiple layers, for example. In any case, a single wooden element typically spans the area between two supports and, as a rule, several wooden elements are arranged next to one another.

It is already known to design building ceilings as so-called composite ceilings, in which a lower section is typically made of wood and a section above it is made of concrete. An advantage of such composite ceilings is that the wood layer serves as permanent formwork and thus the production is simplified. The wood layer represents an advantage in terms of building physics for the space below the ceiling. In terms of strength and rigidity, composite ceilings benefit from the high tensile strength of wood and the fact that the entire cross-section of the wood can absorb tensile forces, which is in contrast to a pure concrete ceiling , in which tensile forces can essentially only be absorbed by the reinforcement. In the case of a composite ceiling, the wood is mainly subjected to tension and the concrete is mainly subjected to pressure, so that the advantageous properties of these building materials are optimally used.

the DE 198 18 525 A discloses a wood-concrete composite element in which a wood layer is composed of a plurality of squared timbers, which is connected to a concrete layer via connecting elements. In addition, reinforcement elements are provided within the concrete layer. These are necessary to prevent cracks in the concrete layer from shrinking to avoid curing. The advantages described above can be achieved with such a composite ceiling. However, the strength and in particular the rigidity of such a composite ceiling is inadequate for some applications. Therefore, in some cases too great a thickness of the material layers is necessary in order to meet the given requirements.

Similar variants are also from the WO 2009/150589 A , the EP 0 352 566 A and the DE 102 54 043 A known.

the CH 694 945 A5 discloses a method for producing composite floors according to the preamble of claim 1 and a composite ceiling according to the preamble of claim 6.

A particular disadvantage of the known solutions is that the wood layer, due to the inadequate connection with the concrete layer, also results in a compressive load on the wood which, compared to a tensile load, can typically only be absorbed inadequately.

The object of the present invention is to avoid these disadvantages and to specify a method for producing a composite ceiling and a special composite ceiling so that the strength and rigidity of the composite ceiling can be increased under otherwise identical conditions.

According to the invention, this is achieved by a method in which the reinforcement elements are connected to the connecting elements without play and that a connecting element is used to connect two immediately adjacent wooden elements and that a connecting element is inserted into a groove that is formed between two immediately adjacent wooden elements .

The composite ceiling according to the invention is characterized in that the reinforcement elements are connected to the connecting elements without play, regardless of the concrete layer, and that one connecting element is used to connect two immediately adjacent wooden elements and that one connecting element is inserted into a groove between two immediately adjacent wooden elements is trained.

The main advantage of the present invention is that the transmission of shear forces between wood and concrete takes place not only through the connecting elements, as is the case in the prior art, but also through the reinforcement elements, the connecting elements acting as intermediate links. An essential aspect of the invention is that the connecting elements and the reinforcing elements are connected to one another directly and without the possibility of relative movement, so that the force transmission begins to take effect even with a minimal deformation of the composite ceiling. In the case of an indirect connection via the concrete layer as in the prior art, a Limited relative movement between wood and concrete take place without significant shear forces being transmitted. This can help you at the beginning of a Load deform the wood layer and the concrete layer without significant forces being transferred between them, which not only leads to reduced strength, but also to 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 with minimal deflection and therefore with minimal load. Therefore, the composite ceiling can in principle be treated like a homogeneous carrier, if one disregards the fact that the modulus of elasticity can vary in the direction of the thickness.

It is also an important aspect of the invention that the forces from the wood layer are introduced into the concrete layer over a large area via the connecting elements. As a result, the materials can be used as best as possible to optimize the load-bearing capacity. The wood layer is exclusively, or at least predominantly, subjected to tensile loads, with the entire cross-section being available to absorb the load. This avoids unfavorable compressive stress.

According to the invention, a connecting element is used to connect two immediately adjacent wooden elements. This dual use of the connecting elements is particularly advantageous.

In this context, it is according to the invention that a connecting element is inserted into a groove which is formed by two immediately adjacent wooden elements. As a result, a force is transmitted between a connecting element and the neighboring wooden elements not only through the nails or staples with which the connection is made, but also in a form-fitting manner via the flanks of the groove and the connecting element resting on it.

It is particularly preferred if the reinforcement elements are used in receiving grooves in the connecting elements. As a result, the connection can be established in a simple manner, particularly on the construction site, in that the reinforcing elements, typically in the form of customary structural steel grids, are placed on the connecting elements and hammered into the grooves. It is helpful if the receiving grooves of adjacent connecting elements are aligned accordingly, so that only a minimal deformation of the structural steel mesh is required to establish the connection.

A particularly rigid structure of the composite ceiling can be achieved in that one reinforcement element is connected to several connecting elements.

Particularly when using one-piece solid wood beams as wooden elements, there may be slight height deviations in the middle area of the ceiling after laying because the individual beams are not completely straight. A completely flat underside of the ceiling can in particular be guaranteed by aligning the wooden elements in the height direction before fastening the connecting elements. This can be done, for example, in such a way that individual bars that protrude downwards are placed under in the middle in order to push them slightly upwards.

It is preferably provided that the connecting elements are glued to the wooden elements.

The wooden elements are preferably provided with a hydrophobic protective layer before the concrete layer is applied. This enables a significant reduction in the water absorption of the wooden elements during manufacture, which reduces the risk of undesirable deformations.

It is preferable to build the composite ceiling largely on the construction site, i.e. first the wooden elements are placed on the supports, then the connecting elements are attached and then the reinforcing elements are connected to the connecting elements, after which the concrete layer is applied. It is, however, also possible to carry out some of these activities in a factory and to deliver the composite floor semi-finished or ready-made to the construction site. For example, several wooden elements can already be connected with connecting elements to form larger units when they are delivered to the construction site. If necessary, reinforcement elements or even the concrete layer can then also be applied. In this way, the work on the construction site can be simplified and accelerated.

It has been found to be particularly favorable if the wooden elements are designed as solid wooden beams. This enables a particularly cost-effective solution to be achieved.

A design variant of the invention that is particularly advantageous in terms of construction is characterized in that the wooden elements are beveled on their upper side, so that in each case two adjacent wooden elements form a V-shaped groove running in the longitudinal direction. As a result, a non-positive and positive connection with the connecting elements can be achieved. This is particularly advantageous when the connecting elements are designed as V-shaped profiles.

A statically particularly advantageous solution provides that the connecting elements are arranged parallel to the wooden elements. This allows shear forces to be transmitted to the concrete layer over the entire length of the wooden elements.

According to a preferred embodiment variant of the invention, the connecting elements are designed as profiles which have webs running in the longitudinal direction in which receiving grooves are provided. In addition to an optimal power transmission, the necessary distance between the reinforcement elements and the boundary of the concrete layer can also be ensured in this way. Particularly preferably, the webs running in the longitudinal direction have recesses between the receiving grooves. This also improves the frictional connection within the concrete.

The reinforcement elements are preferably designed as structural steel grids. As a result, the reinforcement can be produced easily and acting in all directions.

A particularly favorable embodiment variant of the invention provides that millings are provided in the wooden elements on a surface facing the concrete layer. In this way, the shear forces between the wooden elements and the concrete layer are not only transmitted via the connecting elements, but also directly on the boundary surface, so that an additional increase in strength and flexural rigidity can be achieved. It is particularly advantageous if the millings are wedge-shaped. The wedges are especially provided in the end areas in such a way that the floor rises towards the center in the position of use and a support surface is provided on the side facing the end which absorbs the shear forces from the concrete layer when the composite ceiling is loaded. This enables, in particular, increased safety in the event of fire, if the connecting elements should fail due to excessive heating.

The millings explained above also provide additional security in the event of a fire, if the connecting elements begin to fail due to extreme heating after prolonged exposure to fire, since the shear forces can then still be transmitted.

A sealing element is preferably provided between two adjacent wooden elements. This can prevent concrete water from seeping through the space between two wooden elements during production and creating unsightly discolorations on the soffit. As a sealing element, for example a bead of fire-retardant intumescent acrylic applied to the bottom of the V-shaped groove.

The fire resistance can in particular be increased in that a fire protection element is provided between two adjacent wooden elements. This is especially designed to be intumescent, i.e. it foams up when heated and prevents fire from burning into the gap between two wooden elements and prematurely destroying the wooden beams or exposing the connecting elements to heating that leads to failure.

Fig. 1

schematisch eine erste Ausführungsvariante einer erfindungsgemäßen Verbunddecke in einer Schrägansicht mit teilweise weggebrochenen Bauteilen;

Fig. 2

ein Detail der Ausführungsvariante von Fig. 1;

Fig. 3

ein weiteres Detail mit teilweise dargestellter Betonschicht;

Fig. 4

eine Draufsicht auf die Verbunddecke der Fig. 1 bis Fig. 3;

Fig. 5

schematisch eine erfindungsgemäße Verbunddecke der Fig. 1 bis Fig. 4 in einer Schrägansicht mit Auflagern;

Fig. 6

ein weiteres Detail;

Fig. 7

eine Schrägansicht einer zweiten Ausführungsvariante von unten;

Fig. 8

die Ausführungsvariante von Fig. 7 in einer Stirnansicht; und

Fig. 9

ein Detail einer weiteren Ausführungsvariante.

The present invention is explained in more detail below with reference to the exemplary embodiments shown in the figures. Show it:

Fig. 1

schematically a first embodiment of a composite ceiling according to the invention in an oblique view with partially broken away components;

Fig. 2

a detail of the variant of Fig. 1 ;

Fig. 3

another detail with partially shown concrete layer;

Fig. 4

a top view of the composite deck of FIGS. 1 to 3 ;

Fig. 5

schematically a composite ceiling according to the invention of FIGS. 1 to 4 in an oblique view with supports;

Fig. 6

another detail;

Fig. 7

an oblique view of a second embodiment variant from below;

Fig. 8

the variant of Fig. 7 in a front view; and

Fig. 9

a detail of another embodiment.

In Fig. 1 shows a section of a composite ceiling according to the invention with partially omitted components.

The composite ceiling consists of several wooden elements 1, which are designed as wooden beams arranged parallel to one another. In each case between two wooden elements 1, a connecting element 2 is provided on the upper side, which is designed as a profile running parallel to the wooden elements 1.

Reinforcement elements 3 in the form of structural steel grids are connected to the connecting elements 2 in such a way that the reinforcement elements 3 run parallel to them just above the wooden elements 1.

How out Fig. 3 As can be seen, a concrete layer 4 is provided above the wooden elements 1, which surrounds the reinforcement elements 3. In the representation of Fig. 3 this is broken away at the front to show the other components.

The wooden elements 1 have an essentially rectangular cross-section, the two upper corners being bevelled so that two adjacent wooden elements 1 each form a V-shaped groove 5 with a triangular cross-section. An equally V-shaped profile with legs 6a, 6b, which forms a connecting element 2, is fitted into this groove. A web 7 is formed on each of the two ends of the profile, which has in the longitudinal direction alternately upwardly protruding sections 7a and horizontally protruding fastening sections 7b in between.

The connecting elements 2 are connected to the wooden elements 1 by nails 8, which are driven obliquely into the V-shaped groove 5 on the one hand and perpendicularly through the fastening sections 7b into the wooden elements 1 on the other hand. Alternatively, screws or clamps are also possible. In addition, the connecting elements 2 can be glued to the wooden elements 1.

In an alternative embodiment variant, not shown here and not according to the invention, a connecting element 2 can also be placed flat on the top of a wooden element 1 in order to ensure the intimate connection of the wooden element 1 with the concrete layer.

On the upper side of the upwardly protruding sections 7a, grooves 9 are provided in which the reinforcement elements 3 are clamped so that they are connected to the connecting elements 2 and thus to the wooden elements 1 without play even before the concrete is introduced. It is essential for the invention that the tight fit ensures that there is always a force fit and form fit between the reinforcement elements 3 and the connecting elements 2, so that a direct transmission of force is guaranteed.

The reinforcement elements are typically hammered into the receiving grooves 9 during manufacture.

The wooden elements 1 have millings 10 which are incorporated in the end regions 12 of the wooden elements 1 on the upper sides 11 facing the concrete layer 4. The millings 10 are wedge-shaped and have a bottom 13 that rises towards the center of the wooden elements 1, so that a support surface 14 is formed in the direction of the ends 5, to which shear forces from the concrete layer 4 can be transmitted. In this way, under load, the concrete layer 4 can also extend over the sections protruding into the millings 10 on the wooden elements 1 and thus transfer additional shear forces. These shear forces act outwards so that the support surfaces 14 can effectively transfer them.

Typically, the composite ceiling according to the invention is at its ends on only in the Fig. 5 bearings 15 shown.

In the case of the Fig. 7 and Fig. 8 In the embodiment variants shown, a fire protection element 17 in the form of a spring is inserted between two adjacent wooden elements 1, which prevents a fire from spreading rapidly upwards from the soffit 16 between the two wooden elements 1. The fire protection element 17 is preferably designed to be intumescent.

As an alternative 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 wooden elements 1 when the concrete is applied and impairing the underside 16 by discoloration. This sealing element 18 can also have an intumescent section in order to offer 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 one in the Fig. 9 The embodiment variant shown differs only in the design of the connecting elements 2, which is why only one such is shown. Only the upwardly protruding sections 7a are executed, but not horizontally protruding fastening sections. Thus, between the upwardly protruding sections 7a and thus also between the receiving grooves 9, there are recesses 19, which ensure a continuous frictional connection in the concrete also transversely to the connecting elements 2.

The composite ceiling can be produced by placing the wooden 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 produced. However, prefabrication can also take place, so that several wooden elements 1 connected to one another are already placed on the supports 15 and then the connecting elements 2 and the reinforcing elements 3 have already been mounted. The concrete layer 4 can also be applied and cured if necessary.

Claims (15)

1. Method for producing composite floors, in which timber elements (1) are placed directly adjacent to one another on supports and are connected to one another, wherein a composite floor is produced by applying a concrete layer (4), and wherein connecting elements (2) are fastened to the timber elements (1) and then reinforcing elements (3) are placed on the connecting elements (2), characterised in that the reinforcing elements (3) are connected to the connecting elements (2) without play, and in that a connecting element (2) is used in each case for connecting two directly adjacent timber elements (1) and in that a connecting element (2) is inserted into a groove (5) which is formed between two directly adjacent timber elements (1).
2. Method according to claim 1, characterised in that the reinforcing elements (3) are inserted into receiving grooves (9) of the connecting elements (2).
3. Method according to claim 1 or 2, characterised in that the timber elements (1) are aligned in the height direction before the fastening of the connecting elements (2).
4. Method according to one of claims 1 to 3, characterised in that the connecting elements (2) are attached to the timber elements (1) after being placed on the supports (15).
5. Method according to one of claims 1 to 4, characterised in that a sealing element is inserted between the timber elements (1), and/or in that a fire protection element is inserted between the timber elements (1).
6. Composite floor, having several timber elements (1) arranged directly adjacent to each other, having a concrete layer which is arranged on the timber elements (1) and which is provided with reinforcing elements (3), wherein connecting elements (2) are attached to the timber elements (1), characterised in that the reinforcing elements (3) are connected to the connecting elements (2) without play independently of the concrete layer (4), and in that a connecting element (2) is used in each case for connecting two directly adjacent timber elements (1), and in that a connecting element (2) is inserted into a groove (5) which is formed between two directly adjacent timber elements (1).
7. Composite floor according to claim 6, characterised in that the timber elements (1) are formed as solid wooden beams.
8. Composite floor according to claim 6 or 7, characterised 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 and preferably the connecting elements (2) are designed as V-shaped profiles.
9. Composite floor according to one of claims 6 to 8, characterised in that the connecting elements (2) are arranged parallel to the timber elements (1).
10. Composite floor according to one of the claims 6 to 9, characterised in that the connecting elements (2) are designed as profiles which comprise webs (7) extending in the longitudinal direction in which receiving grooves (9) are provided and preferably the webs (7) extending in the longitudinal direction have recesses (19) between the receiving grooves (9).
11. Composite floor according to one of claims 6 to 10, characterised in that milled grooves (10) are provided in the timber elements (1) on a surface (11) facing the concrete layer (4) and preferably the milled grooves (10) are of wedge-shaped design.
12. Composite floor according to claim 11, characterised in that the milled grooves (10) are provided in each case in end regions (12) of the timber elements (1).
13. Composite floor according to one of claims 6 to 12, characterised in that the connecting elements (2) are glued to the timber elements (1).
14. Composite floor according to one of claims 6 to 13, characterised in that the connecting elements (2) are connected to the timber elements (1) by nails, staples or screws.
15. Composite floor according to one of claims 6 to 14, characterised in that a sealing element (18) is provided between two adjacent timber elements (1).

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