EP2377660B1 - Method for manufacturing prefabricated construction panels that combine wood and concrete and panels obtained via said method - Google Patents

Description

The present invention relates to the production of prefabricated building panels combining wood and concrete. It relates more particularly to a method for producing prefabricated structural elements to wood-concrete collaboration for the construction of buildings.

The invention is intended to apply for the realization of constructions that may be, but not exclusively, living quarters or professional buildings.

The evolution of modern building techniques has been dictated by a concern for both simplification and speed, but also costs, without compromising the insulation and modularity of buildings, as well as aesthetics. constructions.

The notion of prefabricated construction has thus been known for a number of years to be a boom in the building sector. According to this technique, elements or groups of elements that are manufactured in the factory and then assembled on site to form the complete structure of the building are used to construct a building. These solutions make it possible to pre-realize the constituent elements of the structure from previously prepared plans, and thus to limit the time of intervention on site as well as the footprint of the site. This technique is well known in the prior art. A typical example of prefabricated elements intended for the construction of a structure is for example described in the document FR2556761 .

However, these modalities were limited to the use of concrete as the sole material and other processes were therefore developed to allow to associate with raw concrete a more noble and aesthetic material, offering superior performance in terms of insulation, like wood.

The association between concrete and wood is not new in itself. Traditionally, panels were used that were pressed against the concrete structure once mounted, to form a cladding-type outer wall around the building. The panels thus positioned were generally placed in the vertical plane with connection points at the base and in the upper part, which could pose problems of resistance and resistance to stresses transmitted by the building structure.

To overcome these disadvantages, the known solutions of the prior art teach the use of wood panels that are associated with a concrete plate forming the building facade via metal connecting pieces, leaving a vacuum between the outer face of the concrete and the inner face of the wood panels for filling by means of an insulator.

For example, the document EP1555098 discloses a method for producing prefabricated timber-concrete construction panels associating a concrete base disposed inwardly of the wall of a building and a wooden frame disposed outwardly of this wall. This document describes a method according to the preamble of claim 1 and a panel according to the preamble of claim 5.

Another example of a prefabricated construction panel with wood / concrete collaboration is described in the patent application FR2673963 which illustrates a prefabricated panel in which a set of connecting pieces is provided for hooking a concrete slab to timber chords, the connecting pieces having connectors for transmitting the forces between the timber chords and the concrete slab in the plane of said plate. This modality certainly allows to achieve a combination of wood / concrete for the manufacture of prefabricated building panels. However, according to this document, the association between the wooden members and the concrete support is discontinuous, and is achieved by means of connector tubes which are connected by their respective ends, on the one hand to the concrete, on the other hand to the corresponding surface located on a wooden chord, which involves intermediate layout operations. One end of the connector tube must be embedded in the concrete of the panel and the other end is engaged by force in a groove which has previously been arranged in correspondence in the wooden frame.

To reinforce the strength of the association between the frames and the concrete, it is intended to use intermediate fasteners between each of the connectors, these fastening parts being constituted by screws or nails whose one end is embedded. in the concrete, and the other has a thread or notch engaging the wooden chords. The method described by this document of the prior art to produce prefabricated panels with wood-concrete collaboration therefore imposes many preparatory and intermediate operations, which, even if the result is satisfactory, is nonetheless expensive and complex . Moreover, the wood structure here is the supporting structure.

The principle of connector tubes to achieve a wood-concrete collaboration is also known from the document EP0580228 .

Finally, the document US5561957 describes a connection between a wooden floor and a concrete slab, by means of a metal strip, the lower part of which has a notch designed to penetrate the wooden beams constituting the floor, and the upper part of which has folds designed to be drowned in the concrete once the slab is poured. This modality prevents deformations only in the horizontal plane, and is not transposable to the realization of vertical walls.

The present invention therefore proposes to produce a wood / precast concrete association panel according to claim 5, as well as the method for producing such panels according to claim 1, by simplifying the execution methods while avoiding distribution problems. unequal constraints related to the presence of connection elements likely to move and cause deformation of the wood and concrete structures component panel, under the effect of weather or external phenomena, including weather.

For this purpose, the prefabricated panel according to the present invention is characterized in that its production method comprises a step in which the wood structure is pressed onto the concrete structure during setting of the concrete to ensure optimum positioning and prevent any movement or subsequent removal of the wood part, in the horizontal plane or the vertical plane, and the concrete is simultaneously vibrated.

• la figure 1 est un diagramme représentant les différentes étapes du procédé selon l'invention,
• la figure 2 est une vue en coupe verticale partielle d'un panneau préfabriqué obtenu par la mise en oeuvre du procédé selon l'invention,
• la figure 3 est une vue en élévation du panneau représenté à la figure 2,
• la figure 4 est une vue de détail illustrant l'assemblage du bois et du béton dans le panneau selon la présente invention, et
• la figure 5 est une vue partielle en éclaté montrant un mur de bâtiment réalisé au moyen de panneaux selon l'invention.

The invention will be better understood through the description given below of an embodiment by way of non-limiting example, and with reference to the appended drawings in which:

• the figure 1 is a diagram representing the different steps of the process according to the invention,
• the figure 2 is a partial vertical sectional view of a prefabricated panel obtained by implementing the method according to the invention,
• the figure 3 is an elevational view of the panel shown in figure 2 ,
• the figure 4 is a detail view illustrating the assembly of wood and concrete in the panel according to the present invention, and
• the figure 5 is an exploded partial view showing a building wall made by means of panels according to the invention.

• on dispose sur une table métallique en usine les armatures parasismiques en acier, les coffrages pour les ouvertures, et les réseaux,
• on coule une dalle en béton à plat sur le banc métallique ainsi préparé,
• on pose une ossature en bois sur la base en béton ainsi obtenue,
• on pose une contre-table sur l'ossature en bois pour presser l'ossature en bois contre la base en béton, après calibrage de la distance et en fonction de l'épaisseur prédéfinie pour le panneau avant bardage,
• simultanément, on vibre le béton,
• on relève le panneau après prise du béton.

With reference to the appended figures and in particular the figure 1 , the realization of a prefabricated building panel according to the present invention involves the implementation of a method which comprises the following successive steps:

• steel seismic reinforcements, formwork for openings, and networks are arranged on a metal table at the factory,
• a concrete slab is poured flat on the metal bench thus prepared,
• we put a wooden frame on the concrete base thus obtained,
• a counter-table is placed on the wooden frame to press the wooden frame against the concrete base, after calibrating the distance and according to the predefined thickness for the cladding front panel,
• simultaneously, we vibrate the concrete,
• the panel is lifted after setting concrete.

It is also possible, but not necessarily, one or more of the following complementary steps: installation of a wooden cladding, insufflation of an insulator in the residual spaces, installation of a wooden exterior cladding.

The basic configuration of a prefabricated panel according to the invention is more particularly represented on the figures 2 and 3 .

The panel according to the invention combines a concrete base (1) with a wooden frame (5). The concrete base (1) will be disposed towards the inside of the building wall and the wooden frame (5) outwards.

The wooden frame (5) is composed of a plurality of identical frame members arranged parallel to each other along the length of the concrete base (1). More specifically, each of the frame members consists of a beam (5 ') whose length is slightly greater, of the order of 20 cm, to the width of the concrete base (1), so that once the panel is raised upright, the upper part of the beam (5 ') is above the upper part of the concrete base (1) and acts as a slab formwork.

The beam (5 ') has a first portion, said internal, which is intended to be positioned against the outer surface of the concrete base (1), and has a U-shaped section with two side walls (51). interconnected by a bottom wall (52), said bottom wall forming a 90 ° angle with said side walls. The side walls (51) of the inner part of the beam are identical in size, so that they are each placed in a plane perpendicular to that of the concrete base (1) when the beam (5 ') is pressed against said concrete base (1), the bottom wall (52) of the inner part of the beam connecting the two side walls (51) then being in a plane parallel to that of the concrete base (1).

The inner part of the beam (5 ') thus forms a form around the empty zone delimited by the surface of the concrete base (1) and its bottom walls (52) and side walls (51).

The beam (5 ') further comprises a second portion, said external, consisting of a wooden plank (53) extending opposite the concrete base (1) from the bottom wall (52) the inner part of the beam (5 '), over its entire length. The plank (53) is arranged perpendicular to the bottom wall (52), equidistant from each of the side walls (51) of the inner portion of the beam (5 ').

A metal anchor (3) is arranged and fixed on the inner face of the bottom wall (52) of the inner part of the beam (5 '), parallel to the side walls (51) and in the extension of the plank (53). The metal anchor (3) has a greater width dimension than the side walls (51).

The successive operations carried out to produce a prefabricated building panel according to the present invention by means of the elements described above will now be described.

In a first step, the steel elements (11) intended to stiffen the concrete and the various networks that will be destined subsequently to supply the building once it is built, such as electrical outlets, are arranged in a horizontal table on a horizontal table. or connections to the cable or telephone network. At this stage, reservations are provided that correspond to the openings that are desired, such as doors or windows and the corresponding formwork. Reinforcing elements corresponding to earthquake pillars (2) are also available.

According to an advantageous embodiment, provision can be made for placing at least one heating mat (15) in the lower part of the concrete base (1) to be produced. The heating mat (15) is positioned about 4 centimeters from the outer edge of the inner wall of the prefabricated building element. The heating mat is managed by a progressive warm-up room thermostat (not shown). A probe (not shown) embedded in the concrete veil allows in use not to exceed the maximum temperature of 26 ° C in the concrete panel. The heating sheet (15) is limited in height, to a maximum of 1 m20 from the lower limit of the concrete base, in order to avoid any risk of deterioration if the users or inhabitants wish subsequently to proceed with piercings in the wall walls, for example to hang decorative elements. A copper ground wire (14) is also provided for interconnecting the steel elements of the concrete veil and subsequently grounding the building structure.

In a second step, a concrete base (1) is cast on this metal table. This operation is in itself conventional and has no particularity with regard to the object of the present invention.

In a third step, after casting of the fresh concrete, will be available on the concrete base (1) a wooden frame (5) of corresponding dimensions, constituted as previously said a series of identical beams (5 '), each comprising an inner U-shaped part and a projecting outer part, extended inwards by a metal anchor (3) fixed over the entire height of the bottom wall of said inner part, between the lateral branches. The wood frame includes the reservations for openings corresponding to those provided on the concrete veil that has been poured. At this stage, the wood frame is arranged on the concrete veil so that the projecting metal anchors (3) come into contact with the surface of the concrete base (1). The dimensions of the wood frame (5) are predefined according to the dimensions of the concrete base (1), so that they can be superimposed exactly on one another.

In a fourth step, distance elements (not shown) are placed on the metal table, the height of which is a function of the predefined front thickness of the panel.

In a fifth step, there is generally a metal counter-table of the same size as the metal table, to press the wood frame (5) against the concrete base (1), and simultaneously, one proceeds to a operation, which is in itself conventional, vibrating concrete.

Because of its weight, the counter-table maintains a constant pressure on the wood structure throughout the duration of the vibrating phase of the concrete and will descend to position itself on the spacers. The vibrating operation consists in applying a sequence of vibrations to the fresh concrete once poured. Since concrete consists of a mixture of cement or sand, chippings and other additives, as well as air bubbles, we obtain a better grip and a greater resistance if we promote the mixing of the various components. and we expel the air bubbles.

The main purpose of the vibrating is therefore to optimize the mechanical strength of the concrete by eliminating any bubbles and air pockets present in the concrete that has just been poured. The vibration applied to the assembly lowers the counter-table, which causes, to a depth of about 15 mm, penetration into the fresh concrete of the side walls (51) of the respective inner walls of each of the beams (5 ' ) constituting the timber frame (5),

At the same time, the metal anchoring elements (3) extending the bottom wall of the inner part of each of the beams (5 '), which are longer than the corresponding side walls (51), penetrate more deeply into the fresh concrete from the base (1), about 100 mm.

The counter-table will descend until it comes into abutment against the calibration elements previously mentioned.

As already mentioned above, the side walls (51) of the internal portions of the beams (5 ') form, with the bottom walls (52) corresponding thereto, wood formwork for earthquake pillars (2). The reinforcements of these earthquake pillars (2) were put in place in the first step of the process according to the invention. It should be noted that the seismic pillars (2) whose future right-of-way is at this stage defined by the formings formed by the side walls (51) and bottom (52) of the respective internal parts of the beams (5 '), do not will be sunk only on site. The penetration of the side walls of the internal parts of each of the beams (5 ') in the fresh concrete to a depth of about 15 mm ensures that no deformation of the formwork will occur during the subsequent pouring of the seismic pillars on the site .

At this stage, the timber frame (5) is integral with the concrete base (1). Once the setting of the concrete has been completed, the end part of the formwork defined by the lateral (51) and bottom (52) walls of the internal portions of the beams (5 ') is trapped in the concrete base (1), which will prevent any deformation, which may cause bursting of the formwork during the subsequent pouring of the seismic pillars on the site.

In a sixth step, the panel is raised and ready for use.

The process followed according to the steps described above may comprise complementary steps.

• on pose un bardage (6) en bois sur l'ossature en bois (5),
• on insuffle un isolant (4) dans les espaces résiduels,

According to a first variant, it is possible, after taking up the panel, the following complementary steps:

• a cladding (6) of wood is placed on the wooden frame (5),
• an insulation (4) is blown into the residual spaces,

The cladding (6) is advantageously composed of oriented thin wood slat panels, said OSB, which will be fixed on the edge of each of the planks (53) perpendicular beams (5 ') forming the wooden structure (5). These so-called OSB panels consist of resin-like wood particles, which are glued in several layers, which gives them excellent mechanical performance and ease of use.

• on pose un isolant en plaques sur les panneaux une fois en place sur site.
• on pose un film pare pluie (7) sur l'ossature bois

Alternatively, the following additional steps can be provided instead after the panel is raised:

• plates are insulated on the panels once in place on site.
• we put a rain film (7) on the wood frame

According to a second variant, which can be stacked with the previous one, the outer face of the panel is made by fixing an external covering (10) made of wood on cleats (8) previously put in place on the wooden frame, said cleats permitting then create a ventilation space between the exterior cladding and the wooden frame.

The above description makes it possible to appreciate the advantages provided by the invention. The described method allows the realization of prefabricated construction panels ready for use, perfectly scalable in size and configuration and does not require adjustment operations or adaptation of the various elements that compose it. The wood-concrete collaboration obtained is stable and reliable. Thus, the wooden frame is perfectly inseparable from the prefabricated element when the concrete of the base has taken and dried.

Claims (5)

1. Method for manufacturing prefabricated construction panels that combine wood and concrete, involving associating a concrete base (1) inwardly arranged in a wall of a building and a wood frame (5) outwardly arranged in the wall of the building, in which the wood frame is pressed on the concrete base (1) during the hardening of the concrete by simultaneously performing the concrete vibration.
2. Method according to claim 1 in which the following steps are additionally performed in turn :

   - the earthquake-resisting steel armatures, the forms for the openings and the supply network are arranged on a metal table,

   - a concrete slab is poured horizontally on the metal table,

   - a wood frame is arranged on the concrete base as obtained,

   - spacers are arranged on the metal table,

   - the panel is raised after the hardening of the concrete.
3. Method according to claim 2 in which the step during which the wooden frame is pressed on the concrete base while vibrating simultaneously the concrete, takes place after the step in which the spacers are arranged on the metal table and before the step in which the panel is raised.
4. Method according to claim 2 or claim 3, in which the wood frame (5) is pressed on the concrete base (1) using a metal counter-table having the same size than the metal table to maintain constant pressure on the wood frame during the duration of the concrete vibration phase.
5. Panel obtained via said method according to claims 1 to 4, associating a wood frame (5) and a concrete base (1), and formed by a plurality of parallel identical frame members arranged alongside the concrete base (1), each of said frame members being formed by a girder (5') the length of which is slightly larger than the concrete base (1), the girder (5') having a first inner part intended to be positioned against the surface of the concrete base (1), and having a U shaped section with two side walls (51) joined by a back wall (52), said back wall and said side walls being at a 90 -degree angle, and a second outer part formed by a wood lumber (53) extending opposite to the concrete base (1) from the back wall (52) of the inner part of the girder (5'), and arranged at right angle with the back wall (52), at an equidistant point from each side walls (51) of the inner part of the girder (5'),
   characterized in that the inner part of the girder (5') forms a formwork around the empty zone between the surface of the concret base (1) and its back wall (52) and side walls (51).

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