EP3559364B1 - Permanent concrete formwork and method for manufacturing metal-concrete composite structure using such formwork - Google Patents

Description

Field of the invention

The present invention relates to a device forming a permanent metal formwork for pouring concrete, as well as to the method of manufacturing a metal-concrete composite structure in which such formwork is used.

More particularly, the invention relates to a permanent metal shuttering as well as to a manufacturing process making it possible to manufacture a metal-concrete composite structure with high mechanical strength, for example for a nuclear power station. However, the formwork and the method can be used for other constructions, such as for example for the construction of buildings, industrial buildings, or bridges.

State of the art

In order to manufacture a concrete structure, it is known to use a formwork delimiting a volume in which concrete is poured. When the concrete is dry, the formwork is removed and a concrete structure, such as for example a wall, is thus obtained.

In general, in order to manufacture a concrete structure having a high mechanical resistance, said structure is made of reinforced concrete.

Concrete is known for its compressive strength, but has low tensile strength. A typical example of concrete weakness is the case of a one-storey concrete floor which is supported only at its contour, the central part of said floor then having a good chance of collapsing under its own. weight of the fact that its lower part is taut and that the tensile forces are not taken up.

To make a reinforced concrete structure, a metal frame, generally formed of steel bars, is placed in the volume delimited by the formwork, then the concrete is poured around said frame, and once the concrete has hardened the formwork is removed, thus forming a concrete structure containing a metal frame. The metal bars forming the metal frame are placed in the strained areas of the structure in order to balance the internal forces and thus make it possible to ensure the stability of said structure.

In order to obtain a structure with very high mechanical strength, it is known practice to increase the density of the metal bars of the metal frame. For example, in reinforced concrete structures of nuclear power plants, the density of steel in reinforced concrete is about 4 times higher than in standard reinforced concrete structures.

However, this technique of increasing resistance with increasing reinforcement density is limited. Indeed, from a certain reinforcement density, it is no longer possible to properly place the reinforcements in the concrete because they interfere with each other.

In addition, other problems arise, such as the bad passage of aggregates between the bars of the reinforcement, or the difficulty of expelling air bubbles after the concrete has been poured.

In addition, as part of the construction of a nuclear power plant, the equipment or mechanical parts must be fixed to an anchoring plate in order to fix them to the reinforced concrete structure to be produced.

In order to fix this plate to the structure to be manufactured, the plate has anchor rods which are arranged so as to pass through the metal frame. However, because of the high density of the metal reinforcement, pass the anchor rods of the plate through the mesh of the reinforcement formed by the metal bars. component of the metal frame becomes complicated, and it is sometimes necessary to twist the anchor rods in order to pass said anchor rods through the metal frame. It may also be necessary to move the initial position of the plate to be able to pass the anchor rods through the metal frame.

Thus, the implementation of a plate is a very difficult task, and it is not uncommon to have to make repairs after the removal of the formwork. In addition, the installation of the plates greatly extends the duration of the work.

We know the documents US 2003/0029111 , EP 2617910 , and US 2010/0132291 . We also know the documents JP S6047140 , US 4,211,045 and JP 2012 087538 .

These documents describe an alternative solution to reinforced concrete, for the realization of concrete structures, which is the use of a permanent metal formwork which is an integral part of the concrete structure since it is not removed once the hardened concrete. The permanent metal formwork provides the concrete with tensile strength and thus fulfills the same function as the internal metal reinforcement of reinforced concrete.

In order to connect the metal walls to one another, the permanent formwork comprises spacers connecting said walls. The spacers also make it possible to ensure cohesion between the concrete and the permanent formwork.

However, the use of permanent formwork has several drawbacks. A first drawback is that it is necessary to ensure good cohesion between the formwork and the concrete poured inside in order to ensure that the structure has the desired resistance to mechanical forces.

Another disadvantage is that the anchoring of the plate remains problematic because the plate must be fixed on the formwork, which is done by welding, welding causing problems with deformation of the plate or the formwork.

An additional drawback is also the fact that the maximum load supported by the plate depends on its position on the structure relative to the spacers. Indeed, a plate fixed to the permanent formwork directly opposite a spacer can withstand a maximum load much greater than a plate which is not fixed directly opposite a spacer.

Thus, there is currently no solution making it possible to manufacture a reinforced concrete structure which has a high resistance to mechanical forces, without having any problem for the implementation in connection with the density of the metal reinforcement, on which can be easily fixed a plate whose resistance is certain.

General presentation of the invention

An object of the invention is to provide a permanent metal formwork for concrete making it possible to manufacture a composite metal and concrete structure which has a high resistance to mechanical forces, on which a plate can be easily fixed, and whose maximum load can be achieved. supporting the turntable is certain and important.

Another object of the invention is to provide a method of manufacturing a concrete structure having a high resistance to mechanical forces, the method being simple to implement, and making it possible to easily fix a plate to the structure, the load maximum that the said plate can withstand being certain and important.

• deux parois formées chacune d'au moins une plaque métallique, lesdites parois étant parallèles, situées en regard l'une de l'autre, et espacées l'une de l'autre de manière à délimiter un volume interne du coffrage ;
• des entretoises qui relient les deux parois et qui fixent lesdites deux parois entre elles, les entretoises traversant de part en part lesdites deux parois et faisant ainsi saillie de chaque côté du coffrage;
• des barreaux situés sur chacune des parois et qui font saillie dans le volume interne du coffrage ;

chaque plaque métallique est fixée à la plaque métallique opposée par au moins trois entretoises, une première entretoise étant située à une première extrémité de la plaque métallique, une deuxième entretoise étant située à une deuxième extrémité opposée à ladite première extrémité, et une troisième entretoise étant située dans une région centrale située entre ladite première extrémité et ladite deuxième extrémité, les entretoises comprennent des extrémités filetées, les entretoises étant fixées à la plaque métallique par boulonnage, caractérisé par le fait que les parois comprennent deux plaques métalliques mises bout à bout, ledit coffrage comprenant en outre une barre d'assemblage uniquement déposée sur les entretoises et/ou sur les barreaux, ladite barre d'assemblage comprenant une protubérance à chacune de ses extrémités et étant placée à l'intérieur du volume interne (40) du coffrage en regard de la liaison entre les deux plaques métalliques (50).For this purpose, a permanent concrete formwork is provided for the manufacture of a composite metal / concrete structure, said formwork comprising:

• two walls each formed of at least one metal plate, said walls being parallel, located opposite one another, and spaced from one another so as to delimit an internal volume of the formwork;
• spacers which connect the two walls and which fix said two walls to one another, the spacers passing right through said two walls and thus projecting from each side of the formwork;
• bars located on each of the walls and which protrude into the internal volume of the formwork;

each metal plate is secured to the opposite metal plate by at least three struts, a first strut being located at a first end of the metal plate, a second strut being located at a second end opposite to said first end, and a third strut being located in a central region between said first end and said second end, the spacers comprise threaded ends, the spacers being fixed to the metal plate by bolting, characterized in that the walls comprise two metal plates placed end to end, said formwork further comprising an assembly bar only deposited on the spacers and / or on the bars, said assembly bar comprising a protuberance at each of its ends and being placed inside the internal volume (40) of the formwork in sight of the connection between the two metal plates (50).

The fact of using a permanent formwork eliminates the need for internal metal reinforcements of the reinforced concrete to make a concrete structure.

In addition, the fact that the metal plate is connected to the metal plate located opposite it by at least three spacers distributed in the length of said metal plate makes it possible on the one hand to reinforce the resistance to the mechanical forces provided by the formwork to the concrete structure, and on the other hand ensures a constant spacing between the walls of the formwork.

In addition, the fact that the spacers are threaded bars which protrude from the walls of the formwork and which are fixed to the walls of the formwork by bolting allows on the one hand to be able to visualize the position of the spacers and therefore to easily calculate the maximum mechanical resistance that can support a plate fixed to the formwork, and on the other hand makes it possible to easily fix additional elements on the formwork, such as plates for finishing accessories.

• les barreaux situés en périphérie des plaques métalliques possèdent un diamètre supérieur au diamètre des barreaux situés au centre desdites plaques métalliques, et/ou le nombre de barreaux par unité de surface est supérieur en périphérie des plaques métalliques qu'au centre desdites plaques métalliques, la barre d'assemblage reposant sur les barreaux en périphérie des plaques métalliques ;
• le coffrage comprend une plaque d'étanchéité disposée sur le coffrage à l'extérieur du volume interne et fixée de manière amovible à des entretoises, la plaque d'étanchéité étant située aux extrémités de deux plaques métalliques adjacentes sur toute une hauteur des deux plaques métalliques, de sorte que la plaque d'étanchéité chevauche lesdites deux plaques métalliques adjacentes sur toute leur hauteur ;
• le coffrage comprend un longeron d'alignement disposé sur le coffrage à l'extérieur du volume interne et fixé de manière amovible à des entretoises, ledit longeron d'alignement étant fixé à deux plaques métalliques adjacentes sur au moins la moitié d'une longueur des plaques métalliques.

The device according to the invention is advantageously supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

• the bars located at the periphery of the metal plates have a diameter greater than the diameter of the bars located in the center of said metal plates, and / or the number of bars per unit area is greater at the periphery of the metal plates than in the center of said metal plates, the assembly bar resting on the bars on the periphery of the metal plates;
• the formwork comprises a sealing plate arranged on the formwork outside the internal volume and removably attached to spacers, the sealing plate being located at the ends of two adjacent metal plates over a whole height of the two metal plates , so that the sealing plate overlaps said two adjacent metal plates over their entire height;
• the formwork comprises an alignment spar disposed on the formwork outside the internal volume and removably attached to spacers, said alignment spar being attached to two adjacent metal plates over at least half of a length of the metal plates.

The invention also relates to an assembly comprising two permanent concrete forms according to any one of the characteristics stated above, in which said forms are assembled so that the assembly is L-shaped and that the internal volumes of said forms communicate with each other. , the assembly further comprising connecting bars for fixing said forms to each other, a first connecting bar comprising a first end fixed by bolting to a wall of a first formwork and a second end comprising a protuberance and located at the 'Inside the internal volume of a second formwork, a second connecting bar comprising a first end fixed to a wall of the second formwork and a second end comprising a protuberance and located inside the internal volume of the first formwork.

The invention also relates to an assembly comprising two permanent concrete forms according to any one of the characteristics stated above, in which said forms are assembled so that the assembly is T-shaped and that the internal volumes of said forms communicate with each other. , a first formwork comprising a first wall which comprises two metal plates situated opposite a metal plate forming a second wall of said first formwork, a second formwork being located between the two metal plates of the first wall of said first formwork, said assembly comprising furthermore connecting bars for fixing said formwork together, a first connecting bar comprising a first end fixed to the metal plate forming the second wall of said first formwork and a second end located inside the internal volume of the second formwork , a second connecting bar comprising two ends which each comprise a protuberance and which are located in the internal volume of said first formwork.

The invention also relates to an assembly comprising four permanent concrete forms according to any one of the characteristics stated above, in which said forms are assembled so that the assembly is cross-shaped and that the internal volumes of said forms communicate with each other. , said assembly further comprising connecting bars for fixing said formwork together, a first connecting bar comprising a first end comprising a protuberance and being located in the internal volume of a first formwork, and a second end comprising a protuberance and being located in the internal volume of a second formwork, a second connecting bar comprising a first end comprising a protuberance and being situated in the internal volume of a third formwork, and a second end comprising a protuberance and being situated in the internal volume of a fourth formwork.

• fournir un coffrage permanent à béton selon l'une quelconque des caractéristiques définies précédemment ;
• couler du béton à l'intérieur du volume interne du coffrage.

The invention also relates to a method of manufacturing a concrete structure, characterized in that it comprises the following steps:

• provide a permanent concrete formwork according to any one of the characteristics defined above;
• pour concrete inside the internal volume of the formwork.

• fixer une platine à au moins une entretoise du coffrage par boulonnage.

The method may include the following step:

• fix a plate to at least one spacer of the formwork by bolting.

The invention also relates to a composite metal / concrete structure obtained according to the manufacturing method according to any one of the characteristics stated above.

• deux parois formées chacune d'au moins deux plaques métalliques misent bout à bout, lesdites parois étant parallèles, situées en regard l'une de l'autre, et espacées l'une de l'autre de manière à délimiter un volume interne du coffrage ;
• des entretoises qui relient les deux parois et qui fixent lesdites deux parois entre elles ;
• des barreaux situés sur chacune des parois et qui font saillie dans le volume interne du coffrage ;
• une barre d'assemblage uniquement déposée sur les entretoises et/ou sur les barreaux en regard d'une liaison entre deux plaques métalliques d'une même paroi, ladite barre d'assemblage comprenant une protubérance à chacune de ses extrémités.

According to another aspect making it possible to easily assemble without welding the metal plates forming the walls of the formwork, the invention relates to a permanent concrete formwork for the manufacture of a metal / concrete composite structure, said formwork comprising:

• two walls each formed from at least two metal plates lie end to end, said walls being parallel, located opposite one another, and spaced from one another so as to define an internal volume of the formwork ;
• spacers which connect the two walls and which fix said two walls together;
• bars located on each of the walls and which protrude into the internal volume of the formwork;
• an assembly bar only deposited on the spacers and / or on the bars facing a connection between two metal plates of the same wall, said assembly bar comprising a protuberance at each of its ends.

Such a formwork can include the optional features described above.

Presentation of figures

• la figure 1 représente une vue en perspective d'un coffrage permanent à béton selon un mode de réalisation avant que du béton ne soit coulé à l'intérieur ;
• la figure 2 représente une vue en coupe du coffrage de la figure 1 au niveau d'une partie centrale d'une plaque métallique formant une paroi du coffrage ;
• la figure 3 représente une vue en coupe du coffrage de la figure 1 au niveau d'une partie périphérique de plaques métalliques formant une paroi du coffrage et montrant les barres de liaison réalisant le système d'assemblage permettant de se soustraire à la soudure «bout à bout » des tôles;
• la figure 4 représente une variante possible du coffrage de la figure 1 ;
• la figure 5 représente une structure en béton obtenue en utilisant le coffrage de la figure 1, ladite structure comprenant une première et une deuxième variantes possibles de platines fixées au coffrage ;
• la figure 6 représente une structure en béton obtenue en utilisant le coffrage de la figure 1, ladite structure comprenant une troisième variante possible de platines fixée au coffrage ;
• la figure 7 représente une vue en perspective d'un ensemble en forme de L formé par deux coffrages assemblés ensemble, avant que du béton ne soit coulé à l'intérieur ;
• la figure 8 représente une vue en coupe de l'ensemble de la figure 7;
• la figure 9 représente une vue en perspective d'un ensemble en forme de T formé par deux coffrages assemblés ensemble, avant que du béton ne soit coulé à l'intérieur ;
• la figure 10 représente une vision plus détaillée de l'ensemble de la figure 9 au niveau de la zone de liaison entre les coffrages ;
• la figure 11 représente une vue en coupe de l'ensemble des figures 9 et 10 ;
• la figure 12 représente une vue en perspective d'un ensemble en forme de croix formé quatre coffrages assemblés ensemble, avant que du béton ne soit coulé à l'intérieur ;
• la figure 13 représente une vue en coupe de l'ensemble de la figure 12 ;
• la figure 14 représente sous forme schématique une mise en possible du procédé de fabrication d'une structure en béton selon l'invention.

Other characteristics, aims and advantages of the invention will become apparent on reading the following description of different embodiments shown in the following drawings:

• the figure 1 shows a perspective view of a permanent concrete formwork according to one embodiment before concrete is poured inside;
• the figure 2 shows a sectional view of the formwork of the figure 1 at a central part of a metal plate forming a wall of the formwork;
• the figure 3 shows a sectional view of the formwork of the figure 1 at the level of a peripheral part of metal plates forming a wall of the shuttering and showing the connecting bars forming the assembly system making it possible to avoid “butt” welding of the sheets;
• the figure 4 represents a possible variant of the formwork of the figure 1 ;
• the figure 5 represents a concrete structure obtained using the formwork of the figure 1 , said structure comprising a first and a second possible variants of plates fixed to the formwork;
• the figure 6 represents a concrete structure obtained using the formwork of the figure 1 , said structure comprising a third possible variant of plates fixed to the formwork;
• the figure 7 shows a perspective view of an L-shaped assembly formed by two forms assembled together, before concrete is poured inside;
• the figure 8 shows a sectional view of the entire figure 7 ;
• the figure 9 shows a perspective view of a T-shaped assembly formed by two forms assembled together, before concrete is poured inside;
• the figure 10 represents a more detailed view of the whole figure 9 at the level of the connection zone between the formwork;
• the figure 11 shows a sectional view of all figures 9 and 10 ;
• the figure 12 shows a perspective view of a cross-shaped assembly formed by four forms assembled together, before concrete is poured inside;
• the figure 13 shows a sectional view of the entire figure 12 ;
• the figure 14 shows in schematic form a possible implementation of the method of manufacturing a concrete structure according to the invention.

Description of the invention

As shown on figures 1 , 2 and 3 , a permanent concrete formwork 10 for the manufacture of a composite metal / concrete structure comprises two walls 20 and 30 which are located opposite one another and which are mutually parallel. The two walls 20 and 30 are spaced so that the formwork 10 comprises internal volume 40 delimited by said two walls 20 and 30.

The two walls 20 and 30 each comprise at least one metal plate 50. In the example illustrated in the figures 1 to 3 , the walls 20 and 30 each comprise two metal plates 50 arranged one after the other in the same plane. The metal plates 50 can for example be made of steel.

In order to fix the walls 20 and 30 together, the formwork 10 comprises spacers 60. The spacers 60 pass right through said two walls 20 and 30 projecting from each side of the formwork 10. The spacers 60 are intended to be taken in the concrete once the concrete has been poured inside the volume 40 of the formwork 10.

A plurality of spacers 60 is distributed over the entire surface of the walls 20 and 30 of the formwork 10, preferably in a regular manner. The spacers 60 make it possible to withstand the mechanical forces of the formwork 10. The spacers 60 also make it possible to ensure that the spacing between the walls 20 and 30 is constant.

In order to provide the formwork 10 with good resistance to mechanical forces, each metal plate 50 is fixed to the metal plate 50 located opposite it by at least 3 spacers 60. A first spacer 60 is located at a first end of the metal plate 50, a second spacer 60 is located at a second end of said metal plate 50 opposite to the first end, and a third spacer 60 is located in a central area of said metal plate 50.

The spacers 60 are formed of a threaded bar at its two ends which are fixed to the walls 20 and 30 by bolting. The fact that the spacers are bars, at least the ends of which are threaded and fixed by bolting to the walls 20 and 30, it is possible to easily fix elements to the formwork 10 by screwing them to the threaded ends of the spacers 60 which protrude from the formwork 10.

As visible on the figures 2 and 3 , the bolts which fix the spacers 60 to the walls 20 and 30 of the formwork 10 can be formed by 2 nuts. A first nut 61 is located inside the internal volume 40, and a second nut 62 is located outside the internal volume 40 of the formwork 10.

In addition, the fact that the spacers 60 protrude from the formwork 10 makes it possible to know where the spacers 10 are located in the metal / concrete structure once the concrete has been poured inside the formwork 10 (as can be seen in figures 5 and 6 ), thus making it easy to estimate the resistance to mechanical loads that the equipment can withstand when it is attached to the metal / concrete structure.

The formwork also comprises bars 70 on each of the walls 20 and 30 and which protrude into the internal volume 40 of the formwork 10. The bars 70 are also called “studs” in the technical field of the manufacture of a metal / concrete composite structure. The bars 70 comprise a first end which is fixed to the walls 20 or 30, for example by welding, and a second end directed towards the inside of the internal volume 40 of the formwork 10. The bars 70 have the function of ensuring good cohesion between the walls 20 and 30 and the concrete which is poured into the internal volume 40. Once the concrete poured inside the formwork 10 has hardened, the bars 70 take up the shear forces between the walls 20 and 30 and the concrete. The bars 70 preferably include a protuberance at their second end.

As visible on the figure 3 , the formwork 10 comprises an assembly bar 80 located inside the internal volume 40 facing the connection between two metal plates 50 forming the walls 20 and 30. In the embodiment illustrated in FIG. figure 3 , the formwork 10 comprises a plurality of assembly bars 80. The assembly bar 80 is located at the level of the connection between two metal plates 50 forming the same wall 20 or 30, so as to be facing the two metal plates 50 forming said same wall 20 or 30. Thus, a part of the assembly bar 80 is located opposite a peripheral zone of a first metal plate 50 forming a wall 20 or 30, and a second part of said bar assembly 80 is located opposite a peripheral zone of a second metal plate 50 forming said same wall at 30.

The assembly bar 80 includes a first end 81 and a second end 82 which both include a protrusion. The protuberances at the ends 81 and 82 of the assembly bar 80 may be formed by nuts screwed on the ends 81 and 82 of said assembly bar 80. The function of the assembly bar 80 is to ensure that it is held in position. metal plates 50 forming the same wall 20 or 30. Indeed, when the concrete is poured inside the internal volume 40 and the latter has hardened, the presence of the assembly bar 80 makes it possible to create a mechanical connection of the metal plates 50 forming the same wall 20 or 30.

The assembly bar 80 is only deposited on the bars 70 and / or the spacers 60 so that its installation in the formwork 10 is particularly easy. The assembly bar 80 is therefore not fixed to the struts 60 to the bars 70. However, according to a possible variant, the assembly bar 80 can be fixed by a plastic insert to the bars 70, to the struts 60, or to the bars. walls 20, 30. The assembly bar 80 can also be fixed by a wire, for example a wire, to the bars 70, to the spacers 60, or to the walls 20,30 in order to hold it in position.

The assembly bar 80 makes it possible to assemble the metal plates 50 without welding. The fact of using the assembly bar 80 also makes it possible to reduce the positioning constraints of the metal plates 50, a slight offset being allowed with said assembly bar 80.

The bars 70 located on the periphery of the metal plate 50 preferably have a diameter greater than the diameter of the bars 70 located in the central part of said metal plate 50. Such a variant is advantageous because when the assembly bar 80 rests on the bars 70 located on the periphery of the metal plate 50, the mechanical forces taken up by the assembly bar 80 are transferred to the bars 70, thus subjecting the bars 70 to bending and shear stresses. According to a possible variant, the number per unit area of bars 70 located on the periphery of the metal plate 50 is greater than the number per unit area of bars located in the central part of said metal plate 50, so as to better absorb the forces of tension of the assembly bar 80.

According to a possible variant illustrated on figure 4 , the formwork 10 may include a sealing plate 90 which has the function of prevent concrete from flowing out of the internal volume 40 formwork 10 through the interstices which may exist between the metal plates 50 which form the same wall 20 or 30.

The sealing plate 90 is fixed to the ends of two adjacent metal plates 50 which form the same wall 20 or 30. The sealing plate 90 covers the end of the metal plates 50 over the entire height H of said metal plates 50.

The sealing plate 90 can be attached to the ends of the struts 60 which protrude from the walls 20 and 30, for example by bolting. The sealing plate 90 may for example be a wooden plate. The sealing plate 90 is removable, it is removed once the concrete which has been poured inside the internal cavity 40 has hardened.

The formwork 10 can also include an alignment spar 91 which has the function of ensuring that the metal plates 50 forming the same walls 20 or 30 are indeed in the same plane. The formwork 10 advantageously comprises at least one alignment spar 91 on each of its walls 20 and 30.

The alignment spar 91 is attached to two adjacent metal plates 50 which form the same wall 20 or 30 outside the internal volume 40. The alignment spar 91 is removably attached, it is removed once the concrete which has poured inside the internal cavity 40 has hardened. The alignment spar 91 is fixed to the struts 60 which protrude out of the walls 20 and 30, for example by bolting.

The alignment spar 91 covers at least half of the length L of each metal plate 50 on which said alignment spar 91 is fixed. Such a size of alignment spar 91 makes it possible to ensure better alignment of the two adjacent metal plates 50 in the same plane.

The variant illustrated on figure 4 includes both sealing plates 90 and alignment rails 91, however formwork 10 may include only sealing plates 90, or may include only alignment spars 91.

To the figures 5 and 6 shown is a composite metal / concrete structure 100 which was fabricated with the permanent concrete formwork 10 according to the invention.

The metal / concrete structure 100 comprises a concrete layer B which is surrounded by the walls 20 and 30 of the formwork 10. The fact that the concrete layer B is surrounded by the formwork 10 allows the structure 100 to have a high resistance to weathering. mechanical forces without being in reinforced concrete.

To the figures 5 and 6 Illustrated is a plate 110a, 110b, 110c which is fixed to said concrete structure 100. This plate 110a, 110b, or 110c makes it possible to attach elements of the finishing work to said concrete structure. As illustrated in these figures, the use of the formwork 10 makes it possible to easily fix the plates 110a, 100b, 110c to the structure 100 by fixing them by bolting to the ends of the spacers 60 which protrude out of the concrete structure 100. In addition , it is easy to estimate the maximum resistance of the plates 110a, 110b, 110c, with the number of spacers 60 to which said plates 110a, 110b, 110c are fixed.

Such formwork 10 allows modular use of said formwork 10, so as to easily assemble formwork 10 in the desired manner to form a metal / concrete structure 100 of the desired shape.

To the figures 7 and 8 is shown a possible variant in which a first formwork 11 and a second formwork 12 are assembled to form an L-shaped assembly 200. So that the assembly 200 has an L-shape, the forms 11 and 12 are fixed together by one of their ends and are inclined between them so as to form an angle. On the illustrated variant figure 7 and 8 , the angle is 90 °. The first formwork 11 and the second formwork 12 conform to the embodiment described in figures 1 to 4 .

The forms 11 and 12 are assembled so that the internal volumes 40 of said forms 11 and 12 communicate with one another, and thus the assembly 200 has a single internal volume. Concrete is poured within this single internal volume of assembly 200 to form the desired concrete structure.

The assembly 200 comprises connecting bars 81 and 82 for fixing the formworks 11 and 12 together. A first connecting bar 81 comprises a first end which is fixed to a wall 20 of the first formwork 11, and a second end comprising a protuberance and which is located inside the internal volume 40 of the second formwork 12. A second bar. link 82 comprises a first end which is fixed to a wall 20 of the second formwork 12, and a second end comprising a protuberance and which is located inside the internal volume 40 of the first formwork 11.

The protuberance located at the second end of the connecting bars 81 and 82 may for example be formed of a nut which is screwed on said second end.

The first end of the connecting bars 81 and 82 can be fixed to the wall 20 of the formwork 11 and 12 by bolting. Such fixing by bolting makes it possible to easily fix the connecting bars 81 and 82 to the formworks 11 and 12.

Thus preferably the connecting bars 81 and 82 are bars similar to the connecting bars 80 described in figures 1 to 4 , said connecting bars 81 and 82 being metal bars, generally steel, the 2 ends of which are threaded in order to be able to screw a nut thereon.

The assembly 200 may include a plurality of first tie bars 81 and a plurality of second tie bars 82. The number of connecting bars 81 and 82 is chosen in order to obtain the desired mechanical strength.

We have illustrated figures 9 , 10 and 11 , a possible variant in which a first formwork 13 and a second formwork 14 are assembled to form a T-shaped assembly 210. The first formwork 13 and the second formwork 14 conform to the embodiment illustrated in figures 1 to 4 .

In order for the assembly 210 to have a T-shape, the first formwork 13 and the second formwork 14 are inclined relative to each other, and the second formwork 14 is fixed by one of its ends to a central region of the first formwork 13. The internal volumes 40 of the forms 13 and 14 communicate with each other. In the variant illustrated in figures 9 , 10 and 11 , the forms 13 and 14 are inclined at an angle of 90 °.

The first formwork 13 comprises a first wall 20 which comprises two metal plates 50 which are located opposite a metal plate 50 forming a second wall 30 of said first formwork 13. The second formwork 14 is fixed between the two metal plates 50 of the first wall 20 of the first formwork 13.

The assembly 210 includes connecting bars 83 and 84 for fixing the formwork 13 and 14 together. A first connecting bar 83 comprises a first end fixed to the second wall 30 of the first formwork 13, and a second end comprising a protuberance and located in the internal volume 40 of the second formwork 14. A second connecting bar 84 comprises a first end and a second end each comprising a protuberance, and which is located inside the internal volume 40 of the first formwork 13. The second connecting bar 84 may only be deposited on the bars 70 and / or on the spacers 60 of the first. formwork 13.

The assembly 210 may include a plurality of first tie bars 83 and a plurality of second tie bars 84. The assembly number of connecting bars 83 and 84 is chosen in order to obtain the desired mechanical strength.

Preferably, the first connecting bar 83 is fixed to the second wall 30 of the first box 13 by bolting. The protuberances formed at the ends of the link bars 83 and 84 may be formed by nuts screwed to the ends of said link bars 83 and 84. The link bars 83 and 84 may be similar to the link bars 81 and 82 illustrated in figures 7 and 8 .

According to a possible variant, the T-shaped assembly 210 can also be formed from at least three shuttering, this variant comprising two shuttering instead of the first shuttering 13.

We have illustrated figures 9 , 10 and 11 , a possible variant in which a first formwork 15, a second formwork 16, a third formwork 17, and a fourth formwork 18 are assembled to form an assembly 220 in the form of a cross (also called an X form). The forms 15, 16, 17, and 18 are in accordance with the embodiment illustrated in figures 1 to 4 . The internal volumes 40 of the forms 15, 16, 17 and 18 communicate with each other.

In order for the assembly 220 to have a cross shape, the forms 15, 16, 17 and 18 are all assembled at one end.

The assembly 210 includes connecting bars for fixing the forms 15, 16, 17 and 18 together.

A first connecting bar 85 comprises a first end comprising a protuberance which is located in the internal volume 40 of the first formwork 15, and a second end comprising a protuberance which is located in the internal volume 40 of the second formwork 16.

A second connecting bar 86 comprises a first end comprising a protuberance which is located in the internal volume 40 of the third formwork 17, and a second end comprising a protuberance which is located in the internal volume 40 of the fourth formwork 18.

The assembly 210 may include a plurality of first tie bars 85 and a plurality of second tie bars 86. The number of tie bars 85 and 86 is chosen in order to obtain the desired mechanical strength.

The protrusions formed at the ends of the link bars 85 and 86 may be formed by nuts screwed at the ends of said link bars 85 and 86. The link bars 85 and 86 may be similar to the link bars 81 and 82 illustrated in figures 7 and 8 .

• 1000: fournir un coffrage permanent à béton selon l'une quelconque des variantes de l'invention. Le coffrage à béton peut être une des variantes décrites dans les précédentes figures.
• 2000 : couler du béton à l'intérieur du volume interne du coffrage. À la suite de cette étape, et une fois le béton durci, une structure composite métal/béton selon l'invention est obtenue.
• 3000 : fixer une platine à au moins une entretoise du coffrage par boulonnage. Cette étape est toutefois optionnelle, car une platine est fixée au coffrage uniquement lorsqu'un équipement doit être fixé à la structure en béton.

As shown on the figure 14 , the method according to a possible implementation of the invention comprises the following steps:

• 1000: provide a permanent concrete formwork according to any one of the variants of the invention. The concrete formwork can be one of the variants described in the previous figures.
• 2000: pour concrete inside the internal volume of the formwork. Following this step, and once the concrete has hardened, a metal / concrete composite structure according to the invention is obtained.
• 3000: fix a plate to at least one spacer of the formwork by bolting. This step is however optional, because a plate is fixed to the formwork only when an equipment has to be fixed to the concrete structure.

The method can also include a step in which formworks are assembled in order to form an assembly comprising several forms, as for example in the variants illustrated in figures 9 to 13 . The number of forms assembled and the shape of the assembly are adapted according to the shape of the desired metal / concrete structure. The concrete is poured once the forms are assembled.

Claims (10)

1. A permanent concrete formwork (10) for the manufacture of a metal-concrete composite structure (100), said formwork (10) comprising:

   • two walls (20, 30) each formed of at least one metal plate (50), said walls (20, 30) being parallel, located facing each other and spaced apart from each other so as to delimit an internal volume (40) of the formwork (10);

   • struts (60) connecting the two walls (20, 30) and securing said two walls (20, 30) together, the struts (60) passing right through said two walls (20, 30) and thereby protruding from each side of the formwork (10);

   • bars (70) located on each of the walls (20, 30) and protruding in the internal volume (40) of the formwork (10),

   each metal plate (50) is secured to the opposite metal plate (50) by at least three struts (60), a first strut (60) being located at a first end of the metal plate (50), a second strut (60) being located at a second end opposite said first end, and a third strut (60) being located in a central region located between said first end and said second end, and the struts (60) comprise threaded ends, the struts (60) being secured to the metal plate (50) by bolting, characterized in that the walls (20, 30) comprise two metal plates (50) placed end-to-end, said formwork (10) further comprising an assembly rod (80) only deposited on the struts (60) and/or on the bars (70), said assembly rod (80) comprising a protrusion at each of its ends and being placed inside the internal volume (40) of the formwork facing the connection between the two metal plates (50).
2. The permanent concrete formwork (10) according to claim 1, wherein the bars (70) located at the periphery of the metal plates (50) have a diameter greater than the diameter of the bars (70) located in the center of said metal plates (50) and/or the number of bars (70) per unit area is greater at the periphery of the metal plates (50) than in the center of said metal plates (50), the assembly rod (80) resting on the bars (70) at the periphery of the metal plates (50).
3. The permanent concrete formwork (10) according to claim 1 or 2, wherein the formwork (10) comprises a sealing plate (90) disposed on the formwork (10) outside the internal volume (40) and removably secured to struts (60), the sealing plate (90) being located at the ends of two metal plates (50) adjacent over an entire height (H) of the two metal plates (50), so that the sealing plate (90) overlaps said two metal plates adjacent (50) over their entire height (H).
4. The permanent concrete formwork (10) according to any one of claims 1 to 3, wherein said formwork (10) comprises an alignment beam (91) disposed on the formwork (10) outside the internal volume (40) and removably secured to struts (60), said alignment beam (91) being secured to two metal plates (50) adjacent over at least half a length (L) of the metal plates (50).
5. An assembly (200) comprising two permanent concrete formworks (11, 12) according to any one of claims 1 to 4, wherein said formworks (11, 12) are assembled so that the assembly (200) is L-shaped and that the internal volumes (40) of said formworks (11, 12) communicate with each other, the assembly (200) further comprising connection rods (81, 82) for securing said formworks (11, 12) together, a first connection rod (81) comprising a first end secured to a wall (20, 30) of a first formwork (11) and a second end comprising a protrusion and located inside the internal volume (40) of a second formwork (12), a second connection rod (82) comprising a first end secured to a wall of the second formwork (12) and a second end comprising a protrusion and located inside the internal volume (40) of the first formwork (11).
6. The assembly (210) comprising two permanent concrete formworks (13, 14) according to any one of claims 1 to 4, wherein said formworks (13, 14) are assembled so that the assembly (210) is T-shaped and that the internal volumes (40) of said formworks (13, 14) communicate with each other, a first formwork (13) comprising a first wall (20) that comprises two metal plates (50) located facing a plate metal (50) forming a second wall (30) of said first formwork (13), a second formwork (14) being located between the two metal plates (50) of the first wall (20) of said first formwork (13), said assembly (210) further comprising connection rods (83, 84) for securing said formworks (13, 14) together, a first connection rod (83) comprising a first end secured to the metal plate (50) forming the second wall (30) of said first formwork (13) and a second end located inside the internal volume (40) of the second formwork (14), a second connection rod (84) comprising two ends that comprise each a protrusion and that are located in the internal volume (40) of said first formwork (13).
7. The assembly (220) comprising four permanent concrete formworks (15, 16, 17, 18) according to any one of claims 1 to 4, wherein said formworks (15, 16, 17, 18) are assembled so that the assembly (220) is cross-shaped and that the internal volumes (40) of said formworks (15, 16, 17, 18) communicate with each other, said assembly (220) further comprising connection rods (85, 86) for securing said formworks together, a first connection rod (85) comprising a first end that comprises a protrusion and that is located in the internal volume (40) of a first formwork (15), and a second end that comprises a protrusion and that is located in the internal volume (40) of a second formwork (16), a second connection rod (86) comprising a first end that comprises a protrusion and that is located in the internal volume (40) of a third formwork (17), and a second end that comprises a protrusion and that is located in the internal volume (40) of a fourth formwork (18).
8. A method for manufacturing a metal-concrete composite structure (100) characterized in that it comprises the following steps:

   - (1000): providing a permanent concrete formwork (10) according to any one of claims 1 to 4;

   - (2000): casting concrete inside the internal volume (40) of the formwork (10).
9. The manufacturing method according to claim 8, wherein said method comprises the following step:

   - securing a platen (110a, 110b, 110c) to at least one strut (60) of the formwork (10) by bolting.
10. A metal-concrete composite structure (100) obtained according to the manufacturing method according to claim 8 or 9.

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