EP3856994A1

EP3856994A1 - Composite ceiling construction

Info

Publication number: EP3856994A1
Application number: EP19778980.3A
Authority: EP
Inventors: Benjamin KROMOSER
Original assignee: Universitaet fuer Bodenkultur Wien BOKU
Current assignee: Universitaet fuer Bodenkultur Wien BOKU
Priority date: 2018-09-28
Filing date: 2019-09-26
Publication date: 2021-08-04
Also published as: WO2020064899A1

Abstract

The invention relate to assembly which is formed as a self-supporting composite ceiling construction extending along at least one main extension-direction (1), comprising a first load-bearing layer (2) of an armoured and cured casting compound (3) that extends along the main extension direction (1) and, when loaded as intended, is loaded in compression, a second load-bearing layer (4) of at least one wooden board that extends at least along the main extension direction (1) and, when loaded as intended, is loaded in tension, wherein the first load-bearing layer (2) extends at a distance from the second load-bearing layer (4), and wherein a hollow space (6) between the first load-bearing layer (2) and the second load-bearing layer (4) is kept free.

Description

Composite ceiling construction

The invention relates to an arrangement according to the preamble of the independent claim. In particular, the invention relates to an arrangement which as

self-supporting composite ceiling construction, specifically designed as a wood-concrete composite ceiling construction.

Such designs are known and published in different embodiments. It is a known advantage of wood-concrete composite ceilings that wood has advantageous tensile properties and concrete has advantageous pressure properties. For this reason, combinations of these two materials can be used on the tension or compression side of a ceiling construction.

In known ceiling constructions, however, the building materials are often not used efficiently. In conventional systems, for example, a wood-concrete composite ceiling with an 8 m span requires approximately 180 mm thick cross-laminated timber and 90 mm thick concrete. Cross-laminated timber is already complex to manufacture and the degree of utilization of the raw material is less than 30%. The production of concrete and especially cement is also energy-intensive. This underlines the importance of an efficient and optimized use of building materials.

In conventional systems, a wooden ceiling supported with beam-shaped supports or with solid, flat wooden elements is usually formed, which is then cast from above with a reinforced casting compound. Through this direct If the concrete is in contact with the wood, there is a significant proportion of the material used in the area of the neutral fiber of the composite construction, in the area of which low forces occur.

In addition, composite structures are known in which elongated beams running along the direction of tension are at least partially embedded in a concrete ceiling.

With conventional precast concrete parts, the problem arises that pipes cannot be subsequently inserted into solid concrete parts or only with great effort. In the case of composite structures that are optimized in terms of strength, there can also be the problem that cast-in installation lines cover the entire

Weaken composite construction.

The object of the invention is now to provide an arrangement by which the disadvantages of the prior art are overcome. In particular, an arrangement is to be created which is resource-saving and yet permits a high load-bearing capacity with little deformation under a working load. In addition, an arrangement is to be created which is easy to handle, which includes that the

Making the arrangement can be done easily and efficiently, and that too

Installation lines simple and reliable - even after formation or

Completion of the arrangement - can be relocated.

The object of the invention is particularly characterized by the features of

Claims resolved.

The invention relates in particular to an arrangement which is designed as a self-supporting composite ceiling construction running along at least one main direction of extension, comprising:

- A running along the main direction of extension and at

Intended load on the first base layer made of a reinforced and hardened casting compound, - A running along the main direction of extension and at

Intended loading of tensile base layer from at least one wooden panel running along the main direction of extension,

the first base layer being spaced apart from the second base layer,

- And wherein a cavity is kept clear between the first base layer and the second base layer.

According to the invention it is provided that spacer elements are provided, that the spacer elements are firmly connected to the first support layer, that the

Extend spacer elements from the first base layer to the second base layer and thereby penetrate the cavity, and / or that the spacer elements are positively coupled to the second base layer to form a shear joint along the main direction of extension.

If appropriate, it is provided that the spacer elements are formed from the casting compound of the first base layer and in particular are formed in one piece with the first day layer.

It is optionally provided that the spacer elements are each finger-shaped and / or prism-shaped.

If necessary, it is provided that the transition region between the first base layer and the spacing elements is in each case rounded in order to avoid stress peaks.

If necessary, it is provided that the first base layer runs above and the second base layer below the neutral fiber of the composite ceiling construction.

If necessary, it is provided that the first base layer extends over several

Wood panels of the second base layer extends.

If necessary, it is provided that the first base layer has a continuous plane-shaped outer surface. If necessary, it is provided that the second base layer has a continuous, planar outer surface, which is optionally composed of several wooden panels.

If appropriate, it is provided that at least one form-locking element is provided, which is fixedly connected to the second support layer and is different from the second

Base layer extends in the direction of the first base layer and projects into a spacer element and / or is cast into a spacer element.

If necessary, it is provided that a plurality of interlocking elements are provided, each of which extends from the second base layer into one of the spacer elements

extend.

If appropriate, it is provided that the casting compound of the first base layer is formed from concrete or mortar or the like, and / or that a pourable and subsequently curing casting compound, such as concrete, mortar, is used for the first base layer.

If necessary, it is provided that the at least one wooden panel of the second base layer is made of glulam, stacked timber or cross-laminated timber, and / or that the second base layer or the at least one wooden panel is made of a material with good tensile properties, of solid wood, of composite and / or glued wood products , such as glulam, cross laminated timber, plywood,

Laminated veneer lumber, or other wood-based materials exists or is formed.

If appropriate, it is provided that at least one formwork is provided which extends along the inside of the first base layer and remains in the composite ceiling construction as lost formwork, even after the casting compound has hardened.

It is optionally provided that the formwork runs along a plurality of spacer elements and in particular forms the casting mold for the spacer elements. It is optionally provided that the formwork runs between the casting compound and the cavity in such a way that the cavity is kept clear during the casting and curing of the first base layer and the spacer element.

It is optionally provided that the cavity is formed or delimited by the inside of the second base layer and the formwork sealingly connected to the second base layer.

It is optionally provided that the formwork on at least one

Spacer and abuts the inside of the first base layer.

It is optionally provided that the formwork is positively coupled to the second base layer along the at least one main direction of extension, the coupling taking place in particular via means for centering the position of the formwork relative to the second base layer.

If necessary, it is provided that the formwork is constructed in several parts and is preferably composed of several identical formwork parts.

If necessary, provision is made for positive-locking openings, such as milled pockets, to be provided on the inside of the second base layer, into which at least one spacer element and possibly a part of the

Formwork body engages or intervenes.

If appropriate, it is provided that the formwork for the manufacture of the

Form-fit between the first base layer and the second base layer extends into or up to the edge of the form-fitting openings.

If appropriate, it is provided that the formwork to form the

Spacer elements extend in a nozzle-like manner up to the second base layer. If necessary, it is provided that the formwork is formed from a solid, dimensionally stable material such as, for example, from pressed natural fibers, from plastic, from a mineral-bound material such as fiber concrete or from metal.

If necessary, it is provided that the formwork is open in the direction of the second base layer.

If appropriate, it is provided that the cavity is delimited on one side by the second base layer and on the other side by the formwork.

The arrangement according to the invention relates to a self-supporting

Composite ceiling construction. This composite ceiling construction comprises a first base layer which is subjected to pressure when used as intended and a second base layer which is subjected to tensile load when used as intended.

The wooden plate of the second base layer preferably extends — at least along its support direction (s) — across the entire span of the arrangement, ie

in particular from a support of the arrangement to the opposite support of the arrangement in order to be able to absorb tensile forces. If several wooden panels are lined up along the course of the supporting direction in the second base layer, these wooden panels must be connected to one another in order to be able to absorb tensile forces.

If several wooden panels are strung together in the second base layer transversely to the course of a first supporting direction, these wooden panels can be connected to one another so that tensile forces can also be absorbed in the transverse direction, that is to say along a second main direction of extension. This enables a two-axis load-bearing action to be achieved, for example along two main directions of extension.

The first base layer is preferably made of a reinforced and hardened one

Casting compound formed. The second base layer is preferably formed from at least one wooden plate or from another tensile material. Between the two Base layers are kept free at least one cavity. As a result, the first base layer is on one side of the neutral fiber and the second base layer is on the other side of the neutral fiber. This spacing of the two base layers takes place over several spacer elements. These spacer elements are arranged between the first and the second base layer. In order to nevertheless create a shear bond between the first base layer and the second base layer, the spacer elements are connected to both base layers. The spacer elements are preferably fixed to the first at least along the main direction of extension

Base layer and the second base layer connected. This means in particular that the spacer elements connect the first and the second support layer to one another in a form-fitting and / or material-fitting manner in the main direction of extension.

This enables a shear link to be formed.

The invention is based on an exemplary, not

limiting embodiment of the invention further discussed, wherein Fig. 1 shows a schematic sectional view of a possible embodiment of the invention and Figures 2a, 2b and 2c show three steps for producing an arrangement according to the invention.

Unless otherwise stated, the reference symbols correspond to the following

Components:

Main direction of extension 1, first base layer 2, casting compound 3, second base layer 4, wooden plate 5, cavity 6, reinforcement 7, spacer element 8, transition area 9, neutral fiber 10, planar outer surface (of the first base layer) 1 1,

planar outer surface (of the second base layer) 12, form-fit element 13, formwork 14, formwork part 15, form-fit opening 16.

Fig. 1 shows a schematic sectional view of part of an arrangement which is designed as a self-supporting composite ceiling construction. The

Composite ceiling construction runs along a main direction of extent 1, which in the conventional installation position is aligned horizontally as a ceiling. Depending on the use, the main direction of extension 1 can be inclined. As a self-supporting construction, the arrangement does not require any additional supports or columns Unfolding their effectiveness. Rather, it is sufficient if the arrangement rests on supports at the edge or at its ends.

Fig. 1 shows only a part of an arrangement, which is shortened on both sides for reasons of illustration. Depending on the span, this part can be repeated along the main extension direction 1 or along the line by repeating the features shown

Carrying direction can be extended. The arrangement can also be widened transversely to the main direction of extent 1. As a rule, wooden panels 5 are used, which extend from one support to the opposite support. Alternatively, several wooden panels 5 are connected to one another so that they can absorb tensile forces over the entire span. If the length of the arrangement is increased, more spacer elements 8 are generally also used. In all embodiments, the spacer elements 8 can be regularly distributed over the course of the arrangement.

If necessary, further support elements, such as intermediate columns or supports, can also be provided for further support. However, the basic arrangement can be formed as a self-supporting arrangement without further support.

The arrangement comprises a first base layer 2 made of a casting compound 3, which in the standard case has a reinforcement 7. This reinforcement 7 is only shown schematically and can be designed as a conventional reinforcement, for example as a bar reinforcement, mesh reinforcement, basket reinforcement, mesh reinforcement or as a fiber reinforcement.

Furthermore, the arrangement comprises a second base layer 4. The second base layer 4 is preferably formed from a wood material and therefore comprises a wood plate 5 made from wood or from a wood material.

A cavity 6 is kept free between the first base layer 2 and the second base layer 4. Installation lines can be laid in this cavity 6, for example. In addition, this cavity 6 can also serve as insulation. The cavity 6 is penetrated by spacers 8. These spacer elements 8 extend from the first base layer 2 to the second base layer 4.

In particular, these spacer elements 8 are connected or coupled to the first base layer 2 and the second base layer 4 such that the two base layers 2, 4 form a shear bond.

In the present embodiment, the spacer elements 8 are essentially formed by the potting compound 3. In this embodiment, the spacer elements 8 are formed in one piece with the first base layer 2 and preferably cast simultaneously with this first base layer 2. The spacer elements 8 thus also consist at least partially of the casting compound 3 of the first base layer 2.

The spacer elements 8 are positively coupled to the second support layer 4 along the main direction of extent 1. A relative movement of the first base layer 2 with respect to the second base layer 4 along the main direction of extent 1 is thereby blocked. The first base layer 2 and the second base layer 4 are also spaced apart from the neutral fiber 10 by this spacing by the spacer elements 8. This makes the first one when the load is as intended

Base layer 2 under pressure and the second base layer 4 under tension. The

For this purpose, spacer elements 8 penetrate the cavity 6 and engage in the second base layer 4.

In particular, in the present embodiment, a form-fitting opening 16 is provided in the second support layer 4 for each spacer element 8, which

present embodiment is designed as a pocket-shaped recesses or openings.

In addition to the connection described, a form-locking element 13 can also be provided, as also in this embodiment. At least one positive locking element 13 is provided for each positive locking opening 16 or for each spacing element 8. The interlocking elements 13 each extend from the second base layer 4 to a spacer element 8 and, if appropriate, to the first base layer 2 Form-fit elements 13 can be designed, for example, as screws screwed into the wooden plate 5 in the area of the form-fit opening 16, screwed-in bolts, or as headed studs. The connection of the first base layer 2 to the second base layer 4, in particular via the spacer elements 8, can be further improved by means of these positive locking elements 13.

In order to further improve the strength of the arrangement, the transition region 9 between the spacer element 8 and the first base layer 2 can be rounded.

As already described, the first base layer 2 and preferably also the

Spacer elements 8 are formed by a hardened casting compound 3, such as mortar or concrete. In order to obtain the desired shape, formwork 14 is preferably provided. The formwork 14 delimits the cavity 6 on the one hand and the first base layer 2 and the spacer elements 8 on the other hand. The formwork 14 is thus arranged between the casting compound 3 and the cavity 6. On the other hand, the cavity 6 is delimited by the second base layer 4 or the wooden plate (s) 5. In order to prevent the not yet cured casting compound 3 from entering the cavity 6, the formwork 14 is preferably connected to the second base layer 4 in a sufficiently sealing manner, so that the cavity 6 is kept free during casting. A planar outer surface 11 of the first base layer 2 is formed by or during the casting. In the present case, the second base layer 4 also has a planar outer surface 12.

In the present embodiment, the formwork 14 extends over

nozzle-shaped bulges into the form-fitting openings 16. As a result, the formwork 14 is already in its position in relation to the second one before the casting

Base layer centered.

After the casting compound 3 has been cast and hardened, the form-fitting holder or connection is provided in any case via the spacer elements 8 projecting into the form-fitting openings 16 and, if appropriate, via the form-fitting elements 13. The arrangement according to the invention can be carried out as in FIGS. 2a to 2d.

In a first step, FIG. 2a, the second base layer 4 is provided. This is essentially formed by a wooden plate 5 made of a wooden material. The second base layer 4 comprises, on the side facing the first base layer, form-fit openings 16 in the finished arrangement. In these form-fit openings 16, form-fit elements 13 can be provided to further increase the strength of the composite.

In a second step, the formwork 14 is attached, as shown in FIG. 2b. For this purpose, a first formwork part 15 is brought into contact with the second base layer 4 in one step. In the present embodiment, the formwork 14 is designed as a multi-part formwork 14, which is formed by a plurality of formwork parts 15

is composed. Alternatively, a one-piece formwork 14 can also be used.

The first formwork part 15 or the formwork 14 has a special shape which enables the cavity 6 to be kept free. The formwork 14 is not designed as a solid body, such as, for example, as a wooden body or as a foam body, but rather as a thin-walled body that extends, for example, in a vaulted manner, over the cavity 6.

Subsequently, the formwork 14 can be completed, several formwork parts 15 being put together for this purpose in the present embodiment. To form the spacer elements 8, the formwork 14 has a plurality of neck-shaped extensions which extend as far as the second base layer 4 and preferably up to the

Form-fit openings 16 extend.

When or after the formwork 14 is provided, the reinforcement 7, not shown here, can be arranged, if necessary with suitable spacers to provide the concrete cover. In particular, the reinforcement 7 can be placed on the formwork 14. If necessary, the reinforcement 7 with the Form-locking elements 13 are connected. In particular, the reinforcement 7 can be designed in accordance with the prior art.

If the arrangement of the second base layer 4, the formwork 14 and the reinforcement 7 is now complete, the sealing compound 3 can be introduced. For this purpose, the casting compound 3 is poured onto the formwork 14. The reinforcement 7 is poured into the casting compound 3. The potting compound 3 also penetrates into the nozzle-shaped extensions of the formwork 14 in order to form the spacer elements 8 and around

if necessary, pour the form-locking elements 13. If the casting compound 3 has hardened, the spacer elements 8 engage in a form-fitting manner

Form-fitting openings 16 and the arrangement according to the invention is formed.

In principle, the arrangement can either be prefabricated in the factory or cast or manufactured on site, i.e. at the intended installation location.

Figures 2a to 2d show a rectangular section of an arrangement according to the invention. Such arrangements are preferably elongated or flat and can form a ceiling, for example the ceiling of a building. Usual spans of such constructions can be about 5 to 12 m. The width of the arrangement or individual sections of the arrangement can be limited to 2.5 m in order to enable transportability on a conventional truck. However, elements that are more than 2.5 m wide can also be transported by tilting the elements or by moving them upright.

If the arrangement is formed on site, the first base layer 2 can be formed as a single flat base layer which extends over the entire floor. If necessary, however, the first base layer 2 can also be produced in sections.

The reinforcement 7 can preferably rest directly on the formwork 14, if appropriate with suitable spacers to provide the concrete cover. Fastening to the form-locking elements 13 is not absolutely necessary. In all embodiments, the formwork 14 can be fixed or held in a predetermined position by means of position centering with respect to the second base layer 4. An example of such a means for centering the position are nozzle-shaped extensions which extend into the form-fitting openings 14. Another example of a means for centering the position is a shoulder at the end of a nozzle-shaped extension of the formwork 14, which on the outer edge of a

Form-fit opening 16 rests. Another example is a combination between a shoulder and a section of the nozzle-shaped extension projecting into a form-fitting opening, as shown for example in FIG. 1.

An example of an arrangement for a payload of 2-5 kN / m ² and a span of 5-12m can have the following dimensions, for example:

Overall construction height: 200-350mm

Wood panel thickness: 100-200mm (spruce glulam)

Concrete thickness: 60-100 mm (concrete strength class C16 / 20 to C50 / 60)

Grid distance of the spacing elements: 0.4-1 m

Claims

1. Arrangement that as along at least one main extension direction (1)

running and self-supporting composite ceiling construction is formed, comprising:

- A along the main direction of extension (1) and at

first load-bearing layer (2) made of a reinforced and hardened casting compound (3) which is subjected to the intended load under pressure,

- A along the main direction of extension (1) and at

Intended load on the second base layer (4) from at least one wooden panel (5) running along the main direction of extension (1),

- The first base layer (2) being spaced apart from the second base layer (4),

- A cavity (6) is kept free between the first base layer (2) and the second base layer (4),

- wherein spacer elements (8) are provided,

- The spacer elements (8) are firmly connected to the first base layer (2),

- The spacer elements (8) extending from the first base layer (2) to the second base layer (4) and thereby penetrating the cavity (6),

- characterized in that the spacer elements (8) to form a shear joint along the main direction of extension (1) are positively coupled to the second base layer (4).

2. Arrangement according to claim 1, characterized in that the spacer elements (8) from the sealing compound (3) of the first base layer (2) are formed and in particular are integrally formed with the first day layer.

3. Arrangement according to claim 1 or 2, characterized in that the

Spacer elements (8) are each finger-shaped and / or prism-shaped.

4. Arrangement according to one of claims 1 to 3, characterized in that the transition region (9) between the first base layer (2) and

Spacer elements (8) are each rounded to avoid voltage peaks.

5. Arrangement according to one of claims 1 to 4, characterized in that the first base layer (2) above and the second base layer (4) below the neutral fiber (10) of the composite ceiling construction.

6. Arrangement according to one of claims 1 to 5, characterized in that the first base layer (2) extends over a plurality of wooden panels (5) of the second base layer (4).

7. Arrangement according to one of claims 1 to 6, characterized in that the first base layer (2) has a continuous plane-shaped outer surface (1 1).

8. Arrangement according to one of claims 1 to 7, characterized in that the second base layer (4) has a continuous plane-shaped outer surface (12), which is optionally composed of several wooden plates (5).

9. Arrangement according to one of claims 1 to 8, characterized in that at least one form-locking element (13) is provided, which is firmly connected to the second base layer (4) and from the second base layer (4) towards the first base layer (2) extends and protrudes into a spacer element (8) and / or is cast into a spacer element (8).

10. Arrangement according to claim 9, characterized in that several

Interlocking elements (13) are provided, each extending from the second base layer (4) to one of the spacer elements (8).

11. Arrangement according to one of claims 1 to 10, characterized in that the casting compound (3) of the first base layer (2) is formed from concrete or mortar.

12. Arrangement according to one of claims 1 to 1 1, characterized in that the at least one wooden plate of the second base layer (4) made of solid wood or of a composite or glued wood product, such as glulam, cross laminated timber, plywood or laminated veneer lumber.

13. Arrangement according to one of claims 1 to 12, characterized in that at least one formwork (14) is provided which extends along the inside of the first base layer (2) and as lost formwork (14), even after the casting compound has hardened (3), remains in the composite ceiling construction.

14. Arrangement according to claim 13, characterized in that the formwork (14) runs along a plurality of spacer elements (8) and in particular forms the casting mold for the spacer elements (8).

15. Arrangement according to one of claims 13 or 14, characterized in that

- That the formwork (14) between the casting compound (3) and the

The cavity (6) runs in such a way that the cavity (6) is kept free during the casting and curing of the first base layer (2) and the spacer element (8),

- And / or that the cavity (6) is formed by the inside of the second base layer (4) and the formwork (14) sealingly connected to the second base layer (4).

16. Arrangement according to one of claims 13 to 15, characterized in that the formwork (14) on at least one spacer element (8) and on the inside of the first base layer (2).

17. Arrangement according to one of claims 13 to 16, characterized in that the formwork (14) along the at least one main direction of extension (1) is positively coupled to the second base layer (4), the coupling in particular via means for centering the position of the formwork (14) relative to the second base layer (4).

18. Arrangement according to one of claims 13 to 17, characterized in that the formwork (14) is constructed in several parts and is preferably composed of several identical formwork parts (15).

19. Arrangement according to one of claims 1 to 18, characterized in that on the inside of the second base layer (4) positive locking openings (16)

are provided, in which, for the form-fitting coupling of the first base layer (2) and the second base layer (4), at least one spacer element (8) and possibly a part of the formwork body engage or engage.

20. The arrangement according to claim 19, characterized in that the formwork (14) for producing the positive connection between the first base layer (2) and the second base layer (4) extends into or up to the edge of the form-fitting openings (16).

21. Arrangement according to one of claims 13 to 20, characterized in that the formwork (14) to form the spacer elements (8) extends at several points in a nozzle shape up to the second base layer (4).

22. Arrangement according to one of claims 13 to 21, characterized in that the formwork (14) is formed from a solid, dimensionally stable material such as, for example, from pressed natural fibers, from plastic, from a mineral-bound material such as fiber concrete or from metal.