EP3868970A1 - Mixed prefabricated slab for construction, in particular for floors or walls, and manufacturing method - Google Patents

Abstract

The subject of the invention is a prefabricated composite slab (1) for the construction in particular of floors or walls, comprising a wooden frame (2) formed of a plurality of beams (3) and a concrete plate (4), connected to said framework (2) by assembly means, said beams (3) and said concrete plate (4) having an internal face (30, 40) and an external face (31, 41). It is characterized in that the assembly means comprise a plurality of profiles (5) substantially "I" made of wood or a material derived from wood, having two opposite side faces (6), and four longitudinal faces (7 , 8, 9, 10) in pairs, as well as means for bonding each section (5) on the one hand to the internal face (40) of the concrete plate (4) and on the other hand to the internal face (30) of a beam (3). The invention also relates to a method of manufacturing such a mixed wood-concrete slab (1).

Description

The present invention relates to a prefabricated composite slab for the construction in particular of floors or walls, comprising a wooden framework formed of a plurality of beams and a concrete plate connected to said framework by assembly means, said beams and said concrete plate having an internal face and an external face, while the assembly means comprise on the one hand a plurality of profiles substantially "I" made of wood or a material derived from wood, having two lateral faces opposites and four longitudinal faces two by two opposite, and on the other hand means for bonding each section to the internal face of a beam, the internal face of the concrete plate comprising a plurality of grooves extending parallel to each other , designed to accommodate a first end portion of a section, with an axis parallel to the axis of the section.

The invention also relates to a method of manufacturing such a slab.

At present, mixed slabs are used in the construction of all types of buildings and can be integrated in apartment buildings or in buildings for professional use, regardless of the nature of the primary structure or carrier, the latter of which are designed for both horizontal, vertical and inclined structures.

In a known manner, the fact of using mixed slabs makes it possible to benefit from the strong complementarity of the two materials used, resulting from their respective mechanical properties. Thus, since concrete exhibits very good compressive strength and low tensile strength, while wood exhibits opposite properties, such a solution makes it possible to use wood in the tensioned zone in gravity bending and concrete in the compressed zone with a mechanical and mass optimization.

In addition, mixed wood-concrete slabs are renowned for their excellent sound and thermal insulation properties and have the advantage of offering a good fire resistance allowing them to define an effective screen against the direct propagation of a possible fire from one area of a building to another.

Different manufacturing techniques for mixed wood-concrete slabs are currently practiced.

The traditional solution consists in pouring concrete directly on wooden beams already installed at the site level, then in mechanically connecting the two materials by means of connectors of variable geometries, types and methods of fixing, which will end up integrated into the thickness of the the slab.

However, it has been observed that the application of a wet process to wooden elements, linked to the pouring of concrete directly on the site, strongly penalizes the wooden structure on which moisture absorption problems have been observed. Aesthetic drawbacks due to the drying out of the concrete were also noted. In addition, the total duration of the site is impacted by the essential time it takes for the concrete to dry between each operation and by the need to solidly support the wooden frame of the floor until sufficient concrete strength is obtained. .

The second method currently used to manufacture mixed wood-concrete slabs consists of using prefabricated elements, assembled directly on site or in the workshop and then transported to their place of installation. This technique advantageously allows an assembly speed equivalent to that of entirely wooden structures, and to eliminate the problems of shoring and moisture uptake of the wood mentioned above. In addition, the use of prefabricated elements guarantees obtaining standard products, perfectly calibrated and controlled in terms of mechanical properties, easier to integrate into the design of buildings. The on-site assembly of prefabricated elements in the factory also allows better technical control of manufacturing. Thus, the industrialization of manufacturing processes makes it possible to guarantee a level of quality and to increase the level of finish of the elements, while reducing costs. The use of prefabrication also has the advantage of being able to avoid any bad weather on site.

However, it has been observed that the development of this method is currently leveling off, in particular due to the difficulties encountered during the step assembly, which is based on the implementation of appropriate assembly means.

In fact, the connectors used must have specific properties, allowing them in particular to ensure the most rigid connection possible between the wood and the concrete, so as to limit the sliding between the two materials, and thus guarantee a good composite action of the floor. The more effective this composite action, the greater the rigidity of the floor.

In this regard, various solutions for mechanically bonding prefabricated concrete slabs to wooden joists have been proposed. In practice, to date, conventional means such as screws or lag screws are generally used, which have the advantage of flexibility and simplicity of implementation. However, such connecting elements must be installed in large numbers to ensure a sufficient connection, which increases the time required to produce composite slabs and consequently their overall cost.

More sophisticated systems, such as those described in the publications FR 2,584,758 and EP 2 377 660 were also imagined. Nevertheless, their structure is generally complex and supposes a specific implementation for which the workers must first acquire the corresponding gestures.

In addition, whatever the known assembly means employed, it has been observed that the desired properties, linked to the composite nature of wood-concrete slabs, are not equivalent to those obtained through solutions based on the casting of the concrete. concrete on site. In particular, none of the available assembly systems makes it possible to maintain optimum slab rigidity, nor to preserve the recommended “diaphragm” effect.

Thus, to the knowledge of the present applicant, none of the means currently proposed for assembling a prefabricated concrete plate to wooden beams is entirely satisfactory, both from the point of view of their implementation and that of the product obtained.

The aim of the present invention is to provide a solution making it possible to overcome all of the drawbacks mentioned above, in order to promote the commercial development of mixed wood-concrete slabs. To this end, it aims more particularly to remedy the drawbacks inherent in prefabricated products, through a easy to implement assembly method, which relies on simple structural means while guaranteeing the preservation of the properties linked to the composite nature of the slab. Another goal is to provide a mixed wood-concrete slab, designed to be used both in a horizontal position for making floors, as well as in a vertical or inclined position to make partition walls, load-bearing exterior walls, cages. 'elevators or stairs, etc.

To this end, the present invention relates to a slab of the type indicated in the preamble, characterized in that at least the first end portion of the profile has two chamfers, symmetrical with respect to the axis of the profile, and s' each extending between two adjacent longitudinal faces of the section and in that the assembly means also comprise means for bonding each section to the internal face of the concrete plate.

In a preferred embodiment of the slab according to the invention, it can also be provided that the beams each have on their internal face a groove of complementary shape to a second end portion of a section, of parallel axis. to the axis of the profile, and opposite the first end portion.

In addition, such a groove preferably has a depth extending over at least 1/3 of the height of the beam.

The bonding means are for their part preferably chosen from the group comprising a two-component epoxy resin adhesive and a polyurethane adhesive.

In some cases, mechanical assembly means may further be provided to secure the profiles to the concrete plate and to the plurality of beams in addition to the bonding assembly means.

The subject of the invention is also a method of manufacturing a slab as described above, in which a concrete plate having an internal face and an external face is manufactured by molding and said concrete plate is connected by means. of assembly to a wooden frame formed of a plurality of beams comprising an internal face and an external face, characterized in that one uses as assembly means, a plurality of profiles substantially in "I", made of wood or a material derived from wood, and in that each section is glued on the one hand to the internal face of the concrete plate and on the other hand to the internal face of each of the beams.

As part of a preferential implementation of this method, provision is made to provide on the one hand in the internal face of the concrete plate a plurality of grooves extending parallel to each other, designed to accommodate a first portion. end of a section, with an axis parallel to the axis of the section, and on the other hand, in the internal face of each of the beams, a groove designed to accommodate a second portion of the section, with a parallel axis to the axis of the profile, opposite to the first portion.

Alternatively, the step of manufacturing the plurality of grooves can be carried out either by machining the concrete plate previously manufactured by molding, or concomitantly with the manufacture by molding of the concrete plate, using a mold. of appropriate shape.

In addition, according to a specific feature of the method according to the invention, it is advantageously possible to use profiles of which at least the first end portion has two chamfers, symmetrical with respect to the axis of the profile, and each extending between two adjacent longitudinal faces of the profile.

To assemble the concrete plate to the plurality of beams, a step is then preferably provided in which to manufacture the slab according to the invention, the first end portion of a profile is housed and fixed by gluing respectively in a groove of the concrete plate and the second end portion in the groove of a beam.

• [Fig.1] correspond à une vue en coupe transversale d'une dalle mixte selon l'invention conforme à une première variante de réalisation envisageable,
• [Fig.2] correspond à une vue agrandie du détail D de la figure 1,
• [Fig.3] illustre une vue en perspective de la dalle de la figure 1,
• [Fig. 4] est à une vue semblable à celle de la figure 2, correspondant à une seconde variante de réalisation de la dalle selon l'invention,
• [Fig. 5] est à une vue semblable à celle de la figure 2, correspondant à une troisième variante de réalisation de la dalle selon l'invention, et
• [Fig. 6] est à une vue semblable à celle de la figure 2, correspondant à une quatrième variante de réalisation de la dalle selon l'invention.

The advantages resulting from the present invention will become apparent on reading the description which follows relating to embodiments illustrated in the accompanying drawings in which:

• [ Fig. 1 ] corresponds to a cross-sectional view of a composite slab according to the invention in accordance with a first possible variant embodiment,
• [ Fig. 2 ] corresponds to an enlarged view of detail D of the figure 1 ,
• [ Fig. 3 ] illustrates a perspective view of the slab of the figure 1 ,
• [ Fig. 4 ] is at a similar view to that of the figure 2 , corresponding to a second variant embodiment of the slab according to the invention,
• [ Fig. 5 ] is at a similar view to that of the figure 2 , corresponding to a third variant embodiment of the slab according to the invention, and
• [ Fig. 6 ] is at a similar view to that of the figure 2 , corresponding to a fourth variant embodiment of the slab according to the invention.

With reference to the figures, the present invention relates to a prefabricated mixed slab 1 for the construction in particular of floors or walls, comprising a wooden frame 2 formed of a plurality of beams 3 and a concrete plate 4 connected to said frame 2 by assembly means. Conventionally, the beams 3 and the plate 4 have an internal face 30, 40 facing each other and an external face 31, 41 which constitute the external faces of the slab 1.

In the illustrated embodiment, the assembly means comprise a plurality of profiles 5, of axis X, substantially "I", made of wood or a material derived from wood, for example plywood or any equivalent material, having two opposite side faces 6, perpendicular to the X axis, and four longitudinal faces two by two opposite, parallel to the X axis. More precisely, the latter have opposite upper faces 7 and lower 8 and opposite left faces 9 and right 10.

With reference to the figure 2 , each section 5 has two chamfers 11, symmetrical with respect to the axis X, and connecting the upper face 7 with respectively the left face 9 and the right face 10. The two chamfers 11 and the upper face 7 of the section together form a first end portion 12 of the profile 5, a second end portion 13 of which comprises the lower face 8 and the respective lower end zones of the left 9 and right 10 faces. As illustrated in figure 2 , the first and second end portions 12, 13 extend along an axis parallel to the X axis of the profile 5.

Furthermore, it should be noted that in this illustrated embodiment, the concrete plate 4 comprises a plurality of grooves 14, extending parallel to each other, on its internal face 40, and which are designed to accommodate each the first. end portion 12 of a section 5. Likewise, each beam 3 is provided with a longitudinal groove 15, formed on its internal face 30, designed to accommodate the second end portion 13 of a section 5.

The grooves 14 are preferably obtained during the manufacture by molding of the concrete plate 4, but can also result from a subsequent machining of the latter previously dried. The grooves 15 are for their part obtained by appropriate machining of the beams 3.

In terms of dimensions, the composite slab illustrated in the figures has a width of approximately 1.2 m. It consists of a concrete plate 4 with a thickness e of approximately 70 mm, each groove 14 of which has a depth p substantially equal to 25 mm. Furthermore, each beam 3 of the wooden frame 2 has a height h of about 30 mm and a width l of about 100 mm, while the groove 15 with which it is provided has a depth p1 substantially equal to 5 mm. It should also be noted that each groove 14 has opposite inclined walls 16 forming an angle α of between 85 ° and 95 °, preferably 94 °, with the internal face 40 of the concrete plate 4. This angle α corresponds to the angle of inclination of the chamfers 11 included in each section 5. Of course, these values are only given by way of non-limiting example. In practice, the composite slab according to the invention and its constituent elements can of course have any other dimensions, specifically adapted to the applications and to the needs of the corresponding sites.

As indicated above, the profiles 5 make it possible to connect the concrete plate 4 to the beams 3 of the wooden frame 2. For this purpose, the first and second end portions 12, 13 of each profile 5 are respectively inserted into a groove 14 of the plate 4 and the groove 15 of a beam 3. They are fixed in their respective housings by means of an adhesive, for example of the polyurethane type or of the two-component epoxy resin type allowing the both to achieve the assembly characteristics required by the standards in force in the construction industry, and to guarantee a total absence of slippage between the wood of the profiles 5 and the concrete of the plate 4. Thus, the implementation of 'An assembly based on wooden profiles 5 and an adhesive makes it possible to preserve a perfect composite action of the constituent materials of the composite slab 1 according to the invention.

Of course, in accordance with the present invention, mechanical assembly means can also be used in addition to the glue, if necessary.

Although the invention has been described with regard to a particular embodiment, it is understood that it is in no way limited thereto and that various types can be made to it. modifications of form, materials and combinations of these various elements, without departing from the scope and spirit of the invention.

In particular, other variant embodiments have already been imagined by the present applicant, in which the second end portion 13 of the section 5, intended to interact with the groove 15 of a beam 3, has a structure making it possible to further strengthen the bonding bond. Thus, an alternative embodiment is for example envisaged in which the second end portion 13 of the profile has a structure similar to that of the first end portion 12. In other words, in this example the second end portion also has two chamfers then extending respectively between the faces 8 and 10 and the faces 8 and 9 (cf. fig. 4 ), the groove 15 then being shaped correspondingly.

In the same spirit, the lower face 8 of the section 5 can be shaped so as to include a series of teeth extending parallel to each other over its entire length (cf. fig. 5 ).

Also, another variant (cf. fig. 6 ) in which the groove of the beams 3 has a depth substantially equivalent to the height h of the latter has been imagined.

Claims (11)

Prefabricated composite slab (1) for the construction in particular of floors or walls, comprising a wooden frame (2) formed of a plurality of beams (3) and a concrete plate (4) connected to said frame (2) by assembly means, said beams (3) and said concrete plate (4) having an internal face (30, 40) and an external face (31, 41), while the assembly means comprise on the one hand a plurality of profiles (5) substantially "I" made of wood or a material derived from wood, having two opposite side faces (6) and four longitudinal faces (7, 8, 9, 10) two by two opposite, and on the other hand means for bonding each section (5) to the internal face (30) of a beam (3), the internal face (40) of the concrete plate (4) comprising a plurality of grooves (14 ) extending parallel to each other, designed to accommodate a first end portion (12) of a section (5), with an axis parallel to the axis (X) of the section (5), characterized in that at least the first end portion (12) of the profile (5) comprises two chamfers (11), symmetrical with respect to the axis (X) of the profile (5), and each extending between two faces longitudinal (7, 9, 7, 10) adjacent to the section (5) and in that the assembly means also comprise means for bonding each section (5) to the internal face (40) of the plate (4) of concrete. Slab (1) according to Claim 1, characterized in that the beams (3) each have on their internal face (30) a groove (15) of complementary shape to a second end portion (13) of a section ( 5), with an axis parallel to the axis (X) of the profile (5), and opposite to the first end portion (12). Slab (1) according to Claim 2, characterized in that the groove (15) has a depth p1 extending over at least 1/3 of the height h of the beam (3). Slab (1) according to any one of the preceding claims, characterized in that the bonding means are chosen from the group comprising a two-component epoxy resin adhesive and a polyurethane adhesive. Slab (1) according to any one of the preceding claims, characterized in that the assembly means further comprise mechanical assembly means. A method of manufacturing a slab (1) according to any one of claims 1 to 5, in which a concrete plate (4) having an internal face (40) and an external face (41) is produced by molding, and connects said concrete plate (4) by assembly means to a wooden frame (2) formed of a plurality of beams (3) comprising an internal face (30) and an external face (31), characterized in that which is used as assembly means, a plurality of profiles (5) substantially "I", made of wood or a material derived from wood, and each profile (5) is glued on the one hand to the internal face (40) of the concrete plate (4) and on the other hand to the internal face (30) of each of the beams (3). Method according to Claim 6, characterized in that a plurality of grooves (14) extending parallel to each other, designed to accommodate a first portion, are provided in the internal face (40) of the concrete plate (4). (12) end of a section (5), with an axis parallel to the axis (X) of the section (5), and in that it is housed in the internal face (30) of each of the beams (3) a groove (15) designed to accommodate a second portion (13) of the profile (3), opposite to the first portion (12). Method according to Claim 7, characterized in that during the step of manufacturing by molding the concrete plate (4), a mold is used which makes it possible to produce the plurality of grooves (14) concomitantly. Method according to Claim 7, characterized in that the plurality of grooves (14) are produced by machining the concrete plate (4), previously produced by molding. Method according to any one of claims 7 to 9, characterized in that one uses profiles (5) of which at least the first end portion (12) has two chamfers (11), symmetrical with respect to the axis (X) of the profile (5), and each extending between two adjacent longitudinal faces (7, 9 and 7, 10) of the profile (5). Method according to any one of claims 7 to 10, characterized in that in order to assemble the concrete plate (4) to the plurality of beams (3), the first portion (12) is housed and fixed by gluing respectively. end of a profile (5) in a groove (14) of the concrete plate (4) and the second end portion (13) in the groove (15) of a beam (3). :

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