EP1067254B1 - Casing for reinforcement connection box and reinforcement connection box with such casing - Google Patents

Abstract

The cover, designed for reinforcing elements used to connect two separate cast concrete structures in civil engineering, is in the form of a box with two main faces (2, 12), one of which has holes for the reinforcing elements, and two side faces (3, 4) joining the main faces. The box is made from twin-wall polypropylene with its channels running parallel to the longer dimensions of the main and side faces; it can also have additional panels (50, 51) against the side faces.

Description

Technical area

The invention relates to the field of public works and construction. It is more specifically a new box structure of waiting box. Of Generally speaking, a waiting box is a support device for reinforcements connection between two elements of reinforced concrete construction. A box of waiting encloses the folded ends of the reinforcements in the apparent part intended to be embedded in the concrete of one of the building elements.

Previous techniques

In known manner, during the construction of a building comprising several elements (walls or slabs) made of reinforced concrete, we put in place on the ends upper or side of these elements of metal reinforcements intended for ensure a metallic connection with adjacent elements. These frames have a part that is embedded in the first element, and a second part which will be embedded in the adjacent element.

In known manner, these frames must be held in place during the pouring concrete during the production of a wall or slab. These frames are usually partially contained inside a device called "box waiting ", and consists of a box that encloses the folded ends of the frames while leaving apparent the part of the frames that will be embedded in the concrete. After pouring the concrete, we eliminate the box waiting to appear the ends of the frames that have been isolated from the concrete. The folded ends reinforcements are then unfolded and then embedded inside the adjacent element.

Many structures and box geometries have already been proposed, but they all have multiple disadvantages.

Thus, it has been proposed in EP 0 152 015 to make a box of box waiting from a folded cardboard plate. The use of such a material is advantageous for ensuring easy folding, and in a geometry easily adaptable to the desired size.

Nevertheless, cartons, even selected from water-repellent boards have the essential disadvantage of poorly resisting moisture and especially so in contact with the concrete. Thus, to avoid a too rapid degradation of the cardboard, it is stripping is necessary rather quickly, which is to the detriment of quality of the concrete, and in particular causes the appearance of wrinkles or other irregularities on the entire surface of the concrete. In addition, the operation of eliminate the waiting box is relatively difficult because the tears on the damaged cardboard occur randomly, and the elimination is often by shreds.

A first problem that the invention proposes to solve is that of the resistance of the waiting box to the ambient humidity during storage, and contact of the water contained in the concrete during pouring. Another problem that proposes to solve the invention is that of the late stripping of the box of the box waiting period, that is to say the elimination of the caisson after a very long stay in the concrete contact.

Furthermore, another document FR 2 575 506, EP 0 252 996 has been proposed, and US 4 984 401, to make plastic waiting boxes, and in particular in polyvinyl chloride (PVC). Besides, the harmfulness of the chlorine produced during the combustion of these materials, such a solution has many disadvantages, and in particular a great difficulty in carrying out the operation of stripping. Indeed, the materials used have a certain elasticity which must allow the deformation of the waiting box during its extraction from the reservation created in the concrete element. However, to obtain sufficient rigidity of the entire box, it is necessary to use a material of a thickness important that is more difficult to distort, and virtually impossible to cut, at least with common tools. In addition, with the use of PVC, observed after a few weeks, a chemical reaction between the box and the concrete itself, which makes the formwork difficult, and may tearing of material.

US 4,984,401 discloses a box box according to the preamble of claim 1 can, among other things, be made of polypropylene.

Another problem that the invention proposes to solve is that of the incompatibility between the ease of dismantling and the rigidity of the box.

The invention therefore aims to solve all of these problems by proposing a box box waiting that is easy to manufacture, easily extractable from the reservation in which it is incorporated, while having a high rigidity and resistance to the pressure exerted by the concrete during casting.

Presentation of the invention

• deux faces principales parallèles, dont l'une est percée d'ouvertures de passage des armatures de liaison ;
• deux faces latérales reliant les faces principales.

The invention therefore relates to a box box waiting for the establishment of reinforcing links between two parts of concrete structure, made by folding a sheet of foldable material, and comprising:

• two parallel main faces, one of which is pierced with passage openings of the connecting armatures;
• two side faces connecting the main faces.

• le matériau utilisé pour réaliser les caissons est du polypropylène alvéolaire dont les alvéoles, au moins au niveau des faces principales et latérales, sont parallèles à la plus grande direction du caisson ;
• il comporte des éléments additionnels également en polypropylène alvéolaire, au moins en regard des faces latérales.

This box is characterized in that:

• the material used to make the boxes is cellular polypropylene whose cells, at least at the main and lateral faces, are parallel to the largest direction of the box;
• it comprises additional elements also in cellular polypropylene, at least facing the lateral faces.

In other words, the invention consists in using a material which presents a very good resistance, which gives a very high rigidity to the box waiting while facilitating the extraction of the box by manual cutting from tears made very simply by a tool such as a knife or the like.

Indeed, the cellular polypropylene has the advantage of tearing easily only when a primer or precut has been made in parallel with a cell. Inversely, cellular polypropylene is particularly difficult to tear when no area of weakness has been formed.

The cells of the main and lateral faces are parallel to the largest dimension of the box. In this way, the rigidity of the box is optimal, and the stripping operations are facilitated, since a simple cutting primer to one end of the box allows the tearing of the constituent leaf of the box over its entire length. The presence of additional elements at the level of the faces side rails provides sufficient rigidity to prevent crushing phenomena which are exercised essentially perpendicular to the main face of the caisson. It is therefore possible to use cellular polypropylene sheets of relatively low surface density while maintaining excellent resistance to pressure.

In practice, the box is such that one of the main faces is made by two flaps adjacent to the side faces. Advantageously, at least one of the flaps can extend by a flap which is folded towards the inside of the box to form a reinforcing element substantially parallel to a lateral face. In other words, such a box then comprises a spacer element placed between these faces which improves its resistance to the forces exerted by the concrete during the casting.

The additional elements have cells that can adopt different orientations. Thus, when the cells of the additional elements are parallel to those of the box, it facilitates the possible folding of these elements additional and thus the manufacture of the box. Conversely, when the elements additional cells have cells that are perpendicular to those of the box, the stiffness of the side faces in one direction is very significantly increased perpendicular to the main face of the box, so we get a box of waiting to withstand particularly high pressures while being extremely light.

The additional elements may also adopt forms and architectures very varied.

Thus, the additional elements may be present only in relation to the faces side. The additional elements can also come in front of the flaps forming one of the main faces. They can also come to the eye the central reinforcing element, when it is present.

In a particularly advantageous form, the additional elements can be connected to each other by a common face which is located in look at the main face pierced with openings. In other words, the box comprises a second structure substantially similar to the outer structure, and which constitutes in a way a second internal box.

In practice, the flaps forming one of the main faces can be secured by an adhesive tape, or even by welding.

In practice, the main face on which are formed the openings of passage of the frames may have slots connecting these openings to facilitate the setting up of the frames.

In this case, it may be advantageous for the adhesive tape present on the Opposite face is extended on the face presenting the openings. The adhesive tape can then close the slot located closest to the end of the box, avoiding thereby even the passage of liquid concrete.

In the variant embodiments in which the casings do not have any slot, the frames are introduced into boxes by the ends of the arms waiting.

Brief description of the figures

La figure 1 est une vue de dessus d'un caisson conforme à l'invention montré déplié.

La figure 2 est une vue en coupe transversale de caisson montré en figure 1 une fois replié.

Les figures 3 et 4 sont des vues en coupe transversale des variantes de réalisation du caisson de la figure 2.

La figure 5 est une vue en perspective sommaire du caisson illustré à la figure 4.

La figure 6 est une vue en perspective sommaire du caisson illustré à la figure 5 dans lequel les éléments de renforcement apparaissent de façon distincte du reste du caisson.

La figure 7 est une vue de dessus d'un caisson réalisé conformément à une variante de réalisation comprenant trois volumes distincts, correspondants à des boítes d'attente de plus grande dimension.

La figure 8 est une vue en coupe transversale du caisson de la figure 7.

La figure 9 est une vue en coupe longitudinale médiane de l'extrémité d'une boíte d'attente réalisée conformément à l'invention.

Les figures 10, 11 et 12 sont des vues schématiques en perspective illustrant l'opération d'extraction de la boíte d'attente conforme à l'invention.

The manner of carrying out the invention as well as the advantages which result therefrom will emerge from the description of the embodiments which follow, in support of the appended figures, in which:

Figure 1 is a top view of a box according to the invention shown unfolded.

Figure 2 is a cross-sectional view of the box shown in Figure 1 when folded.

Figures 3 and 4 are cross-sectional views of the variants of the housing of Figure 2.

FIG. 5 is a brief perspective view of the box illustrated in FIG. 4.

Figure 6 is a brief perspective view of the box shown in Figure 5 in which the reinforcing elements appear distinctly from the rest of the box.

Figure 7 is a top view of a box made according to an alternative embodiment comprising three separate volumes, corresponding to waiting boxes of larger size.

Figure 8 is a cross-sectional view of the box of Figure 7.

Figure 9 is a longitudinal longitudinal sectional view of the end of a waiting box made according to the invention.

Figures 10, 11 and 12 are schematic perspective views illustrating the extraction operation of the waiting box according to the invention.

Way of realizing the invention

As already stated, the invention relates to a waiting box equipped with a box made by folding a sheet made of cellular polypropylene.

The geometry of such a sheet (1) is illustrated in FIG. sheet comprises several flaps for forming the different faces of the box. The central flap (2) is intended to form one of the main faces of the box waiting, through which are set up binding frames. This component central (2) is framed by two lateral flaps (3, 4) intended to each form a side faces of the box. These side flaps (3, 4) are adjacent to two additional flaps (5, 6) each to form half of the face main opposite to the main face (2). These shutters (5, 6) extend laterally by flaps (7, 8), of a width substantially equal to that of a lateral face (3, 4), and intended, after folding, when the two extreme edges (9, 10) flaps (5, 6) come into contact, forming a reinforcing element forming a spacer (13) between the main faces (2, 12) of the box, as shown in Figure 2.

Riders (22) passing through the central flap (2) hold the spacer (13) in a vertical position.

The central flap (2), forming one of the main faces extends to the level its small sides, by two rectangular flaps (14, 15), intended to close the ends of the box to ensure tightness. These flaps (14, 15) comprise two tabs (17, 19) intended to penetrate inside the box during the flap of the rectangular flap (14, 15). These two legs (17, 19) are separated by a slot central (20, 21) corresponding to the location of the reinforcing element central (13) forming a spacer.

According to the invention, the box also comprises elements (50, 51) located on the side faces (5, 6) of the box, on the side inside. These additional elements (50, 51) can be either free bands placed inside the box during its folding, or even strips glued or welded on the sheet (1) before folding. Figure 1 illustrates the sheet (1) exempt from these additional elements. These additional elements (50, 51) are also in cellular polypropylene. In the form illustrated in Figure 2, the cells of the additional elements (50, 51) are oriented perpendicular to the cells of the rest of the box, which increases the resistance to the forces perpendicular to the main face (2).

As illustrated in FIG. 2, an additional additional element (53) can also be provided to be placed between the flaps (7, 8) forming the spacer (13). In general, the cells of the rest of the caisson, with the exception additional elements are parallel to the large direction of the main face (2, 12) to ensure a good rigidity of the waiting box while maintaining a minimum weight and ease of extraction of the box.

The cellular polypropylene used has a thickness ranging from one to eight millimeters, preferably between 1.5 and 4 millimeters. The density can vary depending on the size of the waiting box, and can vary between 150 and 1200 grams per square meter, and preferentially be between 150 and 600 grams per square meter. It is possible to use polypropylenes cells with different characteristics between the rest of the box and the elements additional (50, 53). Thus, additional elements consisting of strips made from polypropylene with a thickness of around 4 millimeters, and whose density is between 100 and 600 grams per square meter, preferably close to 500 grams per square meter. The type of cells can be variable, and their section can be indifferently square, slightly rectangular or oblique, or inverted chevrons.

According to another characteristic of the invention, the main phase which comprises the openings (23, 24) intended to receive the metal reinforcements, may have slots (25) connecting the openings (23, 24) of the same frame, to facilitate its implementation. In this case, when the box is totally folded, the two shutters (5, 6) are secured by means of a long adhesive tape (28) which can advantageously extend to the level of the end (14) of the box, and further still, at the slot located the most near the end of the box, as shown in Figure 9. This avoids the slot (25) in question to open under the effect of the elasticity of the feet (29) made in level of the ends of the box.

Of course, the structure of the box according to the invention can be adapted to numerous types of reinforcement, and in particular U-shaped frames (30) comprising two arms (31) passing through the main face (2) of the box, but also the single-sided armatures. In this case, the passage holes of the reinforcements are distributed also on a regular basis, and arranged on both sides of the plane of symmetry central of the box.

Depending on the desired rigidity constraints, it is possible to vary the shape of the additional elements as illustrated for example in Figure 3, in this case, the additional elements are in the form of a band comprising two folds (55, 56) defining three segments (57, 58, 59). The first segment (57) comes opposite the side face (3). The second segment (58) comes opposite the flap (5) forming half of the main face (12). The third segment (59) comes into contact with the flap (7) forming a part of the spacer. In this case, the rigidity of the box is further improved since the first and third segments (57, 59) provide a stiffening of the box in a direction perpendicular to the main face (2), while the second segment (58) ensures the stiffening of the waiting box with respect to the forces exerted perpendicular to the lateral faces (3, 4). The orientation of the alveoli of the additional element (54) can be chosen either perpendicular to the orientation of the cells of the rest of the box, to greatly increase the rigidity of the assembly, or still parallel to the orientation of the cells of the rest of the box to facilitate the realization of the folds (55, 56). In the case where the different segments (57, 58, 59) are made independently, they can each be welded or glued on the faces cores, possibly with a separate orientation of their alveoli. For reasons of symmetry, two identical elements (54) are set place in the same box.

Figures 4 to 6 illustrate an alternative embodiment in which the element additional (60) extends over the entire inner surface of the box. More specifically, the additional element (60) comprises a first segment (64) which comes in front of the main face (2) of the rest of the box. This segment (54) has openings for the passage of reinforcements, located in the same places as those formed on the main face (2). The additional element (60) comprises two lateral segments (63, 65) coming respectively with respect to side faces (3, 4) of the rest of the box. The element (60) also includes two segments (62, 66) engaging the flaps (6, 5) forming the main face (12). Finally, the additional element (60) can also comprise two segments (61, 67) coming into contact with the flaps (7, 8) forming the spacer. In this case placement of the jumper (22) maintains contact between the segments (61, 67) of the additional element and the shutters (7, 8) of the rest of the box.

In this way, an internal structure substantially similar to that of the external box, which greatly increases the rigidity of the box, and all this more than the cells can be chosen by being oriented perpendicular to the big direction of the box.

Nevertheless, the resistance of the whole remains satisfactory by using a additional element which has cells parallel to the main direction of the box, which also has the advantage of facilitating the folding of such an element additional (60). Thanks to this particular structure, it is possible to decrease strongly the thickness of the cellular polypropylene used and therefore its cost price while maintaining a particularly high crush strength.

Depending on the application and size, especially the width of the waiting box, another geometry can be adopted as illustrated in the FIGS. 7 and 8, in which the flaps (35, 36) adjacent to the lateral faces (33, 34) have a width less than half of the main face (32).

In this case, the remaining surface is occupied by an additional chute (40) set up as illustrated in Figure 7, so as to constitute two reinforcing elements (41, 42) forming a spacer, and thus increasing the stiffness and compressive strength of the concrete during casting.

In this case, and as illustrated in FIG. 8, the box may comprise three additional elements (72, 73, 74). The additional elements (72, 74) are place respectively between the lateral faces (33) and (34), and the shutters forming part of the spacer element (41, 42). Element (73) is put in place at the interior of the additional trough (40), and its lateral segments (75, 76) part of the spacer elements (41, 42). It is conceivable that the rigidity of such a box waiting is particularly important.

As already stated, the orientation of the cells of the internal faces (33, 34) and the reinforcing elements (41, 42) can be chosen to provide resistance optimal for crushing. In this case, the flaps (46) at the end of the box are each equipped with three legs (37, 38, 39) separated by slots (44, 45) corresponding to the locations of the reinforcing elements (41, 42) forming spacer (see Figure 7).

As can be seen, the geometry of the invention can be broken down according to desired dimensions of the waiting box. So, in practice, it is possible to make boxes that are one to five centimeters thick and wide between five and twenty five centimeters. The pitch between the openings (23, 24) reception of reinforcements can be chosen according to the constraints of standardization specific to construction.

Preferably, the waiting boxes according to the invention will show a length of the order of one meter, compared with conventional waiting boxes which have a length corresponding to a standard wall height, substantially 2.40 m to 2.50 m. Thus, when setting up waiting boxes according to the invention, two elements will be necessary to cover a space of 2.40 meters. The space between the two waiting boxes as well as the volumes located at the ends of the waiting boxes being intended to receive the concrete during casting. This originality remains consistent with the rules of concrete construction armed.

As can be seen in FIGS. 10 to 12, the extraction operation of the box after the formwork is carried out as follows. When the formwork on which was placed the waiting boxes, was removed, the main face of the box is flush. Simply cut the adhesive tape (28) secured in both shutters (5, 6) forming the main face (12) to unfold and spread the two shutters (5, 6), and show the binding frames.

After cutting with a sharp tool the main face (2) level of the front of the reservation, it exerts an action on the shutters (5, 6) for extract the box.

The elimination of the waiting box is extremely facilitated and all the more that contact between polypropylene and concrete is not the seat of any reaction chemical, and therefore parasitic adhesion, even after a few months.

• une grande facilité de fabrication par une technique simple de pliage,
• une grande rigidité permettant le transport et le stockage de telles boítes d'attente,
• une grande résistance à l'écrasement grâce notamment à la présence d'éléments de renforcement, d'éléments additionnels, et au choix des orientations relatives des alvéoles de ces différents éléments,
• une totale inertie chimique vis à vis du béton et donc une possibilité de conserver le coffrage en place pendant de nombreuses semaines, voire des mois,
• un poids extrêmement faible,
• un faible prix de revient.

It follows from the foregoing that the waiting box according to the invention has multiple advantages and in particular:

• a great ease of manufacture by a simple technique of folding,
• high rigidity for transporting and storing such waiting boxes,
• a high resistance to crushing thanks in particular to the presence of reinforcing elements, additional elements, and the choice of the relative orientations of the cells of these different elements,
• a total chemical inertness with respect to the concrete and thus a possibility of keeping the formwork in place for many weeks, or even months,
• extremely low weight,
• a low cost price.

Claims (10)

1. Preparatory box caisson made of polypropylene for installing linking braces between two parts of a concrete structure, made by bending a sheet (1) of pliable material, and comprising:

   two main parallel faces (2, 12), one of which is pierced with openings (23, 24) for the linking braces to pass through;

   two side faces (3, 4) connecting the main faces (2, 12);

   characterized in that:

   the material used to produce the caisson is honeycomb polypropylene whose cells, at least at the main faces (2, 12) and side faces (3, 4), are parallel to the largest direction of the caisson;

   it comprises additional elements (50, 51) also made of honeycomb polypropylene, at least opposite the side faces (3, 4).
2. Caisson according to Claim 1, characterized in that one of the main faces (12) is produced by two rebates (5, 6) of the sheet adjacent to the side faces (3, 4).
3. Caisson according to Claim 2, characterized in that at least one of the two rebates is extended by a flap (7, 8) which is folded inside the caisson to form a reinforcement element (13) substantially parallel to a side face (3, 4).
4. Caisson according to Claim 1, characterized in that the cells of the additional elements (50, 51) are parallel to those of the caisson.
5. Caisson according to Claim 1, characterized in that the cells of the additional elements (50, 51) are perpendicular to those of the caisson.
6. Caisson according to Claim 1, characterized in that the additional elements (50, 51) come only opposite the side faces (3, 4).
7. Caisson according to Claim 2, characterized in that the additional elements (54) also come opposite the rebates (5, 6) forming one of the main faces (12).
8. Caisson according to Claim 3, characterized in that the additional elements (54) also come opposite the reinforcement element (13).
9. Caisson according to Claim 8, characterized in that the additional elements (60) are connected to one another via a common face (64) situated opposite the main face pierced with openings.
10. Preparatory box including a caisson according to one of Claims 1 to 9.

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