EP3704324B1 - Construction method comprising the production of at least one slab made of concrete and non-prestressed wood, and a slab made of concrete and wood - Google Patents

Description

TECHNICAL AREA

The present invention relates to the technical field of building construction, and more particularly reinforced concrete construction.

PRIOR ART

• le coulé en place, c'est-à-dire sur un chantier, en utilisant des coffrages,
• l'utilisation de prédalles fabriquées généralement en usine, en dehors du chantier.

Several ways of treating a concrete floor are known from the state of the art. The two most common solutions are:

• casting in place, that is to say on a construction site, using formwork,
• the use of pre-slabs generally manufactured in the factory, outside the site.

Casting in place has the disadvantage of the time and labor required for its implementation. In particular, a significant amount of time is essential for the concrete to dry before construction of an upper floor can be started.

The existing hollow core slabs have an unattractive appearance. In addition, these hollow core slabs do not allow easy integration of reservations for water pipes, ventilation pipes, electrical cables, etc. As a result, the use of hollow core slabs is generally limited to industrial buildings or car parks. Thus, there is a need to adapt pre-slabs for use in housing and offices.

Ecological requirements are becoming more and more important in construction. Thus, CO ₂ emissions during construction must be limited. However, the cement necessary for the manufacture of concrete remains a significant source of CO ₂ emissions. We can therefore see that a reduction in the use of cement is desired. In addition, the introduction of bio-sourced insulating panels between the concrete ribs allows a further reduction in the CO ² footprint of the finished floor.

DE102004059590 describes a method of constructing a ceiling, comprising hollow bodies intended to lighten the construction. Hollow bodies are an inverted U shape or a wavy shape. Hollow bodies can be made of metal, plastic, wood, particle board or corrugated cardboard. Hollow bodies leave voids in the slab, which is not entirely satisfactory in terms of mechanical resistance, and acoustic and thermal performance. When workers walk on the site, they risk deforming the hollow bodies, before being covered by a compression slab.

GB1401439 describes a method of constructing a slab, comprising lightweight blocks aimed at lightening the construction. The blocks located at the ends of the slab are provided with a height lower than that of the blocks located between the ends. The blocks can be made of polystyrene, wood wool, metal or cardboard. Polystyrene is not entirely satisfactory in terms of mechanical resistance and ecological footprint. Metal is not entirely satisfactory in terms of cost, ecological footprint, and acoustic and thermal performance. Wood wool and cardboard are not entirely satisfactory in terms of mechanical resistance, and acoustic and thermal performance.

STATEMENT OF THE INVENTION

One of the aims of the invention is therefore to propose an improved construction method, the method comprising the production of at least one concrete and wooden slab. The slab resulting from the process must be aesthetic, resistant, easy to install, ecological to produce, and have good acoustic and thermal performance.

Another objective of the invention is to facilitate the integration of reservations for conduits and cables, and thus make it possible to use the method according to the invention in the construction of buildings, in particular housing.

• coulée d'une dallette de béton ;
• pose de raidisseurs métalliques dans la dallette de béton encore frais ;
• découpe d'au moins deux pains de bois ;
• pose des pains de bois entre les raidisseurs émergeant de la dallette de béton encore frais et en laissant un espace entre les pains de bois adjacents ;
• coulée de nervures de béton entre les pains de bois, en noyant les raidisseurs au moins en partie ; et
• séchage de la dalle non précontrainte constituée de la dallette de béton, des raidisseurs, des pains de bois et des nervures en béton.

To this end, the subject of the invention is a construction method, comprising the production of at least one slab according to the following steps:

• casting of a concrete slab;
• installation of metal stiffeners in the still fresh concrete slab;
• cutting of at least two blocks of wood;
• install blocks of wood between the stiffeners emerging from the still fresh concrete slab and leaving a space between the adjacent blocks of wood;
• casting of concrete ribs between the blocks of wood, drowning the stiffeners at least in part; And
• drying of the non-prestressed slab consisting of the concrete slab, stiffeners, wooden blocks and concrete ribs.

• une dallette de béton ;
• des raidisseurs métalliques intégrés à la dallette de béton ;
• des pains de bois disposés entre les raidisseurs émergeant de la dallette de béton, avec un espace entre les pains de bois adjacents ; et
• des nervures de béton coulées entre les pains de bois, en noyant les raidisseurs au moins en partie.

The invention also relates to a concrete and wooden slab, characterized in that it comprises:

• a concrete slab;
• metal stiffeners integrated into the concrete slab;
• blocks of wood placed between the stiffeners emerging from the concrete slab, with a space between the adjacent blocks of wood; And
• concrete ribs poured between the blocks of wood, drowning the stiffeners at least in part.

• Le procédé comprend, préalablement à la coulée de la dallette de béton, une étape d'identification de zones d'interférences entre, d'une part, les nervures, et d'autre part, des réservations prévues dans la dalle. Les raidisseurs métalliques associés aux nervures hors zones d'interférences sont posés avec un écart de référence entre elles. Les raidisseurs métalliques associés aux nervures dans les zones d'interférences sont posés en décalage avec l'écart de référence, pour éviter lesdites interférences.
• L'écart de référence entre les raidisseurs métalliques est de l'ordre de 60 cm, tandis que le décalage est de l'ordre de 10 cm d'un côté ou de l'autre.
• Le procédé comprend des étapes supplémentaires : pose de la dalle constituée de la dallette, des raidisseurs, des pains de bois et des nervures qui intègrent les raidisseurs et sont solidarisées à la dallette ; puis coulée d'une dalle de compression au-dessus de la dalle en recouvrant les pains de bois et les nervures.
• Les pains de bois ont une densité comprise entre 120 et 140 kg/m3.
• Les pains de bois p1-p3 ont une conductivité thermique comprise entre 0,038 et 0,044 W/(mK).
• Les pains de bois sont en fibres de bois.
• Les pains de bois sont découpés à partir de panneaux isolants monocouches en fibres de bois.
• Pendant l'étape de coulée des nervures de béton entre les pains de bois, les raidisseurs sont noyés seulement en partie dans le béton et émergent au sommet des nervures.
• La découpe des pains de bois peut être effectuée par jet d'eau ou par tout autre système.
• La dallette en béton a une épaisseur de 6 cm.
• La dalle a une longueur allant jusqu'à 7,5m.
• La dalle a une largeur allant jusqu'à 3,8m.
• Le plancher fini a une épaisseur de 23 centimètres pour les portées de 6m51 à 7m50.
• Le plancher fini a une épaisseur de 20 centimètres pour les portées jusqu'à 6m50.

According to other advantageous characteristics of the invention, taken individually or in combination:

• The method comprises, prior to the casting of the concrete slab, a step of identifying areas of interference between, on the one hand, the ribs, and on the other hand, reservations provided in the slab. The metal stiffeners associated with the ribs outside the interference zones are installed with a reference distance between them. The metal stiffeners associated with the ribs in the interference zones are installed offset with the reference gap, to avoid said interference.
• The reference gap between the metal stiffeners is of the order of 60 cm, while the offset is of the order of 10 cm on one side or the other.
• The process includes additional steps: installation of the slab consisting of the slab, stiffeners, blocks of wood and ribs which integrate the stiffeners and are secured to the slab; then pouring a compression slab on top of the slab, covering the wooden blocks and the ribs.
• The blocks of wood have a density of between 120 and 140 kg/m3.
• The p1-p3 wood blocks have a thermal conductivity of between 0.038 and 0.044 W/(mK).
• Wooden loaves are made of wood fibers.
• Wood blocks are cut from single-layer wood fiber insulation panels.
• During the stage of pouring the concrete ribs between the blocks of wood, the stiffeners are only partially embedded in the concrete and emerge at the top of the ribs.
• The cutting of blocks of wood can be carried out by water jet or by any other system.
• The concrete slab is 6 cm thick.
• The slab has a length of up to 7.5m.
• The slab has a width of up to 3.8m.
• The finished floor has a thickness of 23 centimeters for spans of 6m51 to 7m50.
• The finished floor has a thickness of 20 centimeters for spans up to 6m50.

Thanks to the invention, the slab can support the weight of the concrete poured on site (compression slab), giving the floor complex (concrete from the slab, blocks of wood, concrete from the compression slab (cast on site)) good acoustic and thermal performance, and have a very favorable balance in terms of CO2 emissions.

Workers can walk on the slab on site, without risking deformation, before the compression slab is poured. Blocks of wood can support the weight of workers without deforming, which would not be the case with hollow elements or lightweight materials. This facilitates the installation of networks (electrical, fluids, etc.).

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 est une vue en coupe de la dalle obtenue par le procédé selon l'invention ;
• la figure 2 est une représentation schématique en perspective de la dallette avec les raidisseurs, avant la pose des pains de bois ;
• la figure 3 est un plan de calepinage comportant des zones d'interférences entre nervures et réservations, lesdites interférences pouvant être évitées par l'utilisation de la dalle selon l'invention ;
• la figure 4 est un plan similaire à la figure 3, mais avec les nervures déplacées pour éviter les interférences ;
• la figure 5 est un plan de calepinage représentant une zone dans laquelle une dalle avec l'écart de référence entre nervures peut être utilisée ;
• la figure 6 est un plan de calepinage montrant une zone dans laquelle le décalage de nervures ne permet pas d'éviter les réservations.

Other characteristics and advantages of the invention will emerge clearly from the description given below, for information only and in no way limiting, with reference to the appended figures, in which:

• there figure 1 is a sectional view of the slab obtained by the method according to the invention;
• there figure 2 is a schematic perspective representation of the slab with the stiffeners, before the installation of the wooden blocks;
• there Figure 3 is a layout plan comprising areas of interference between ribs and reservations, said interferences being able to be avoided by the use of the slab according to the invention;
• there figure 4 is a plan similar to the Figure 3 , but with the ribs moved to avoid interference;
• there figure 5 is a layout plan representing an area in which a slab with the reference spacing between ribs can be used;
• there Figure 6 is a layout plan showing an area in which the offset of ribs does not allow reservations to be avoided.

For the purposes of simplification, the same elements bear the same numerical references in the different figures.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a construction method, comprising the production of at least one slab 1 in reinforced concrete and wood, called slab BB.

As shown in Figures 1 and 2 , slab 1 is composed of a slab 2, metal stiffeners 3 embedded in concrete, ribs n1 and n2 projecting from slab 2, and blocks of wood p1 to p3 arranged between ribs n1 and n2 . Once slab 1 has been placed on its supports, an upper layer of concrete, called a compression slab (not shown), is poured onto slab 1.

The p1-p3 blocks of wood have a density of between 120 and 140 kg/m3. The blocks of wood p1-p3 have a thermal conductivity preferably between 0.036 and 0.046 W/(mK), preferably between 0.038 and 0.044 W/(mK).

The p1-p3 wooden blocks are preferably made of wood fibers. Still preferably, the p1-p3 wooden blocks are obtained from single-layer insulating panels, rigid or semi-rigid, made of wood fibers. The panels can have a thickness of between 3 and 22 cm, preferably equal to 9 or 12 cm. The panels have a fire behavior corresponding to class E, according to standard EN 13501-1.

A significant problem with existing hollow core slabs is their lack of adaptability. Indeed, they are difficult to use for building housing or offices whose plans are very diverse, and require accepting a significant number of reservations for water, gas and ventilation pipes, as well as for electrical cables. , telecommunications, etc.

According to the invention, the offset of the ribs makes it possible to adapt the slab 1 to the specific needs of each construction project.

To implement the method according to the invention, a preliminary step consists of identifying on the layout plan areas where a (virtual) “collision” occurs between the ribs and the reservations.

• Dans le premier type de zone, il n'y a pas de collisions (cf. Figure 5) entre les nervures n8 à n11 et les réservations r4 à r7. Ainsi, une dalle 1 avec l'écart de référence de 60 cm entre nervures n8 à n11 peut être utilisée.
• Le deuxième type de zone, dite zone d'interférences ZI, présente des collisions (cf. Figure 3). On identifie une première zone d'interférences ZI entre la nervure n1 et la réservation r1, et une seconde zone d'interférences ZI entre la nervure n5 et la réservation r3. Le déplacement des nervures de maximum 10 cm par rapport à l'écart de référence permet d'échapper aux réservations (cf. Figure 4). Ainsi, une dalle 1 avec des nervures n1 et n5 décalées par rapport à l'écart de référence peut être mise en oeuvre.
• Le troisième type de zone (cf. Figure 6) désigne les zones de conflit ZC, où le déplacement de nervures de 10 cm maximum ne permet pas d'éviter les collisions. C'est le cas de la collision entre la nervure n12 et la réservation r8, dont le déplacement provoquerait une collision avec la réservation r9. Ainsi, dans cette zone ZC, un plancher doit être coulé en place, ou être formé de prédalles classiques, sans nervures ni isolant intégré.

Thus, three different types of zones can be identified.

• In the first type of zone, there are no collisions (cf. Figure 5 ) between ribs n8 to n11 and reservations r4 to r7. Thus, a slab 1 with the reference distance of 60 cm between ribs n8 to n11 can be used.
• The second type of zone, called the ZI interference zone, presents collisions (cf. Figure 3 ). We identify a first interference zone ZI between the rib n1 and the reservation r1, and a second interference zone ZI between the rib n5 and the reservation r3. Moving the ribs by a maximum of 10 cm compared to the reference distance allows reservations to be avoided (cf. Figure 4 ). Thus, a slab 1 with ribs n1 and n5 offset relative to the reference distance can be implemented.
• The third type of zone (cf. Figure 6 ) designates ZC conflict zones, where moving ribs by a maximum of 10 cm does not prevent collisions. This is the case of the collision between the rib n12 and the reservation r8, the movement of which would cause a collision with the reservation r9. Thus, in this ZC zone, a floor must be poured in place, or be formed from classic pre-slabs, without ribs or integrated insulation.

1. 1) Coulée d'une dallette 2 de béton. De préférence, la dallette 2 a une épaisseur de 6 cm. Grâce à l'invention, sa longueur peut atteindre 7,5 m, et sa largeur peut atteindre 3,8 m.
2. 2) Pose de raidisseurs 3 métalliques dans la dallette 2 de béton encore frais, à des positions qui sont fonction des réservations et des zones d'interférences ZI, comme décrit au-dessus. Les raidisseurs comprennent des éléments verticaux 3a et des éléments horizontaux 3b. Les éléments 3a dépassent de la dallette 2, tandis que les éléments 3b sont entièrement intégrés à la dallette 2. Les éléments verticaux 3a des raidisseurs 3 sont posés soit avec l'écart de référence entre eux (de préférence 60 cm), soit avec un écart supérieur ou inférieur à l'écart de référence, pour éviter les zones d'interférences ZI.
3. 3) Découpe des pains de bois p1 à p3, de préférence par jet d'eau, aux bonnes dimensions. De préférence, les pains de bois p1 à p3 découpés peuvent avoir une largeur de 48 cm, et une hauteur de 9 ou 12 cm. La longueur des pains de bois p1 à p3 découpés dépend en particulier de la longueur de la dalle 1 à réaliser.
4. 4) Des ouvertures traversantes sont formées dans les pains de bois p1 à p3 pour faire office, par exemple, de passages de câbles. Bien entendu, d'autres conduits et tuyaux peuvent être passés dans ces ouvertures.
5. 5) Pose des pains de bois p1 à p3 entre les éléments verticaux 3a des raidisseurs 3 émergeant de la dallette 2 de béton encore frais. Ainsi, les pains de bois p1 à p3 sont solidarisés avec la dallette 2 par adhérence entre le bois et le béton frais, puis lors du séchage du béton.
6. 6) Coulée des nervures n1 et n2 entre les pains de bois p1 à p3, en noyant les éléments verticaux 3a des raidisseurs 3 en totalité ou en partie.
7. 7) Pose sur site de chaque dalle 1 constituée de la dallette 2, des raidisseurs 3, des pains de bois p1 à p3 et des nervures n1 et n2, qui intègrent les éléments verticaux 3a des raidisseurs 3 et sont solidarisées à la dallette 2.
8. 8) Coulée d'une dalle de compression (non représentée), de préférence d'une épaisseur de 5 cm, au-dessus de chaque dalle 1.

The method of manufacturing the slab 1 according to the invention, described in detail below, comprises the following steps:

1. 1) Casting of a concrete slab 2. Preferably, the slab 2 has a thickness of 6 cm. Thanks to the invention, its length can reach 7.5 m, and its width can reach 3.8 m.
2. 2) Installation of metal stiffeners 3 in the slab 2 of still fresh concrete, at positions which depend on the reservations and the ZI interference zones, as described above. The stiffeners include vertical elements 3a and horizontal elements 3b. The elements 3a protrude from the slab 2, while the elements 3b are entirely integrated into the slab 2. The vertical elements 3a of the stiffeners 3 are placed either with the reference distance between them (preferably 60 cm), either with a deviation greater or less than the reference deviation, to avoid ZI interference zones.
3. 3) Cutting blocks of wood p1 to p3, preferably by water jet, to the right dimensions. Preferably, the cut pieces of wood p1 to p3 can have a width of 48 cm, and a height of 9 or 12 cm. The length of the cut pieces of wood p1 to p3 depends in particular on the length of the slab 1 to be made.
4. 4) Through openings are formed in the blocks of wood p1 to p3 to act, for example, as cable passages. Of course, other conduits and pipes can be passed through these openings.
5. 5) Installation of blocks of wood p1 to p3 between the vertical elements 3a of the stiffeners 3 emerging from the slab 2 of still fresh concrete. Thus, the blocks of wood p1 to p3 are secured to the slab 2 by adhesion between the wood and the fresh concrete, then during the drying of the concrete.
6. 6) Casting of the ribs n1 and n2 between the blocks of wood p1 to p3, embedding the vertical elements 3a of the stiffeners 3 in whole or in part.
7. 7) Installation on site of each slab 1 consisting of slab 2, stiffeners 3, blocks of wood p1 to p3 and ribs n1 and n2, which integrate the vertical elements 3a of stiffeners 3 and are secured to slab 2.
8. 8) Casting a compression slab (not shown), preferably 5 cm thick, above each slab 1.

Of course, a floor can be composed of a plurality of neighboring slabs 1, and thus the casting of the compression slab can be carried out simultaneously for several slabs 1.

Steps 1) to 6) are preferably carried out off-site, for example in the factory, while steps 7) and 8) are carried out on site.

The number of operations carried out on site is minimized.

Alternatively, it may be considered to carry out steps 1) and 2) in the factory, while steps 3) to 8) are carried out on site.

The invention makes it possible to improve the CO ₂ balance of slab 1. This improvement is made possible thanks to the reduction of slab 1, which is no longer a solid slab. The p1-p3 blocks of wood make it possible to reduce the use of primary materials by more than 35%, while retaining the original lift, according to the experiments which led to the invention.

By lightening the floors, it is possible to also reduce the size of the concrete structure made up of posts, beams, foundations, etc.

The p1-p3 blocks of wood, consuming CO ₂ throughout their lifespan, make it possible to further improve the CO2 balance of slab 1, which, potentially, can be zero or even positive. The p1-p3 wooden blocks also increase the thermal and acoustic insulation of slab 1.

The p1-p3 blocks of wood have good fire resistance properties, compared to polystyrene, wood wool or cardboard. The p1-p3 wood blocks also have good moisture resistance properties, compared to wood wool or cardboard.

The use of slag is advantageously possible, to further improve the CO ₂ balance.

Preferably, electric pots can be integrated directly into the slab 2, by being put in place before the casting of the slab 2.

Due to the fact that the reservations, passages and pots are already integrated into the slab 1, the construction method according to the invention is particularly quick and simple to implement, minimizing the operations necessary on the site.

Advantageously, the length of slab 1 can be less than or equal to 7.5 m. Thus, slab 1 can be installed over a maximum span of 7.5 m.

Choosing a width of 3.8 m reduces the number of joints to be treated. Thus, the installation of the slabs 1, obtained by the process according to the invention, is simpler and faster than with the existing pre-slabs.

When installing slab 1, there is no need to position stabilizing props on the underside, saving time, material and effort.

Furthermore, the slabs 1 and the construction can be shaped differently from the Figures 1 to 6 without departing from the scope of the invention. In addition, the technical characteristics of the different embodiments and variants mentioned above can be, in whole or for some of them, combined with each other. Thus, panel 1 can be adapted in terms of cost, functionality and performance.

Claims (10)

1. Construction method, comprising the production of at least one slab (1) according to the following steps:

   - casting a thin slab (2) of concrete;

   - laying of metal stiffeners (3) in the thin slab (2) of freshly cast concrete;

   - cutting at least two blocks of wood (p1-p3), said blocks of wood (p1-p3) being solid, consisting of wood fibres, with a density of between 120 and 140 kg/m³;

   - placing the blocks of wood (p1-p3) between the stiffeners (3) emerging from the thin slab (2) of freshly cast concrete and leaving a space between the adjacent blocks of wood (p1-p3);

   - casting concrete ribs (n1-n6) between the blocks of wood (p1-p3), by at least partly embedding the stiffeners (3); and

   - drying the non-prestressed slab (1) consisting of the thin slab (2) of concrete, stiffeners (3), blocks of wood (p1-p3) and concrete ribs (n1-n6).
2. Construction method according to claim 1, characterised in that it comprises, prior to the casting of the thin slab (2):

   - a step of identifying interference zones (ZI) between, on the one hand, the ribs (nl-n16) and, on the other hand, recesses (r1-r11) provided in the slab (1);

   and in that:

   - the metal stiffeners (3) associated with the ribs (n2-n4, n8-n11) out of interference zones (ZI) are placed with a reference deviation between them; and

   - the metal stiffeners (3) associated with the ribs (n1, n5) in the interference zones (ZI) are placed offset with the reference deviation to avoid said interference.
3. Construction method according to claim 2, characterised in that the reference deviation between the metal stiffeners (3) is of 60 cm, while the offset is of 10 cm on one side or the other.
4. Construction method according to any one of the preceding claims, characterised in that it comprises the following additional steps:

   - placing the slab (1) consisting of the thin slab (2), stiffeners (3), blocks of wood (p1-p3) and ribs (n1, n2) which integrate the stiffeners (3) and are secured to the thin slab (2); and

   - casting a compression slab above the slab (1), covering the blocks of wood (p1-p3) and the ribs (n1, n2).
5. Construction method according to any one of the preceding claims, characterised in that during the step of casting the concrete ribs (n1, n2) between the blocks of wood (p1-p3), the stiffeners (3) are embedded only partially in the concrete and emerge at the top of the ribs (n1, n2).
6. Construction method according to any one of the preceding claims, characterised in that the cutting of the blocks of wood (p1-p3) is carried out by water jet.
7. Construction method according to any one of the preceding claims, characterised in that the thin slab (2) has a thickness of 6 cm.
8. Construction method according to any one of the preceding claims, characterised in that the slab (1) has a length of up to 7,5 m.
9. Construction method according to any one of the preceding claims, characterised in that the slab (1) has a width of up to 3,8 m.
10. Concrete and wooden slab (1), characterised in that it comprises:

    - a thin slab (2) of concrete;

    - metal stiffeners (3) integrated into the thin slab (2) of concrete;

    - solid blocks of wood (p1-p3), made of wood fibres, with a density of between 120 and 140 kg/m³, and disposed between the stiffeners (3) emerging from the thin slab (2) of concrete, with a space between the adjacent blocks of wood (p1-p3); and

    - concrete ribs (n1-n6), cast between the blocks of wood (p1-p3), by at least partly embedding the stiffeners (3).

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