EP1067254A1 - 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 aimed at a new structure of a waiting box box. Of in general, a waiting box is a support device for frames of connection between two reinforced concrete construction elements. A waiting box therefore contains the folded ends of the reinforcements in the exposed part intended to be embedded in the concrete of one of the construction elements.

Previous techniques

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

In known manner, these reinforcements must be kept in place during the pouring concrete during the construction of a wall or slab. These frames are generally partially contained inside a device called "box ", and made up of a box which encloses the folded ends of the reinforcements while leaving visible the part of the reinforcements which will be embedded in the concrete. After pouring the concrete, we eliminate the waiting box to make it appear the ends of the reinforcements which have been isolated from the concrete. The folded ends reinforcements are then unfolded and then embedded inside the adjacent element.

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

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

However, cartons, even selected from water-repellent cartons have the essential drawback of poorly resisting humidity and in particular therefore on contact with concrete. To avoid too rapid degradation of the cardboard, it is necessary to proceed with formwork fairly quickly, which is done at the expense of the quality of the concrete, and in particular causes the appearance of spallings or other irregularities over the entire surface of the concrete. In addition, the operation of eliminating the waiting box is relatively difficult because the tears on the damaged cardboard occurs randomly, and disposal is often done by tattered.

A first problem which the invention therefore proposes to solve is that of the resistance of the waiting box to ambient humidity during storage, and to contact of the water contained in the concrete during pouring. Another problem proposes to resolve the invention is that of the late shuttering of the box casing waiting time, i.e. the elimination of the box after a very long stay at the concrete contact.

Furthermore, another document FR 2 575 506, EP 0 252 996 has been proposed, and US 4,984,401, to produce plastic waiting boxes, and in particular in polyvinyl chloride (PVC). In addition, 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 formwork. 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 whole box, it is necessary to use a material with a thickness important which is more difficult to deform, and practically impossible to cut, at least with common tools. In addition, with the use of PVC, observe after a few weeks, a chemical reaction between the box and the concrete itself, which makes formwork difficult, and can cause material tearing.

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

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

Statement 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 waiting box box for the establishment of connecting reinforcements between two parts of concrete work, produced by folding a sheet of foldable material, and comprising:

• two parallel main faces, one of which is pierced with openings for the passage of the connection fittings;
• 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 includes additional elements also in cellular polypropylene, at least opposite the side faces.

In other words, the invention consists in using a material which has a very good resistance, which gives a very high rigidity to the waiting box 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 being easily torn only when a primer or precut has been made in parallel with a cell. Conversely, 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 box dimension. In this way, the rigidity of the box is optimal, and the formwork removal operations are facilitated, since a simple cutting initiation one end of the box allows tearing of the sheet constituting the box over its entire length. The presence of additional elements on the faces side provides sufficient rigidity to prevent crushing phenomena which are exerted essentially perpendicular to the main face of the box. It is therefore possible to use alveolar polypropylene sheets of relatively low basis weight while retaining excellent resistance to pressure.

In practice, the box is such that one of the main faces is produced 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 reinforcement element substantially parallel to a lateral face. In other words, such a box then comprises a spacer element placed between these faces main, which improves its resistance to the forces exerted by concrete during casting.

The additional elements have cells which 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 therefore the manufacture of the box. Conversely, when the elements additional have cells which are perpendicular to those of the box, the rigidity of the lateral faces is greatly increased in one direction perpendicular to the main face of the box, so we get a box waiting able to withstand particularly high pressures while being extremely light.

Additional elements can also take forms and very varied architectures.

Thus, the additional elements may only be present with regard to the faces side. Additional elements can also come next to the flaps forming one of the main faces. They can also come in addition to the look of the central reinforcement element, when the latter 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 of the main face pierced with openings. In other words, the box comprises a second structure substantially similar to the external structure, and which in a way constitutes a second internal box.

In practice, the flaps forming one of the main faces can be secured either by 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 installation of reinforcements.

In this case, it may be advantageous if the adhesive tape on the opposite side extends over the side with the openings. The adhesive tape can then close the slot located closest to the end of the box, thereby avoiding even the passage of liquid concrete.

In the variant embodiments in which the box does not include slot, the reinforcements are introduced into boxes by the ends of the arms waiting.

Brief description of the figures

The manner of carrying out the invention as well as the advantages which flow therefrom will emerge clearly from the description of the embodiments which follow, in support 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 a box shown in Figure 1 once folded.

Figures 3 and 4 are cross-sectional views of the variants of realization of the box of figure 2.

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

Figure 6 is a summary perspective view of the box illustrated in Figure 5 in which the reinforcing elements appear distinct from the rest of the box.

FIG. 7 is a top view of a box produced in accordance with a variant embodiment comprising three separate volumes, corresponding to larger waiting boxes.

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

FIG. 9 is a view in median longitudinal section of the end of a waiting box produced in accordance with 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 said, the invention relates to a waiting box equipped with a box produced by folding a sheet made of cellular polypropylene.

The geometry of such a sheet (1) is illustrated in Figure 1. Thus, such sheet includes several flaps intended to form the different faces of the box. The central flap (2) is intended to form one of the main faces of the box standby, through which the connection fittings are placed. This component central (2) is framed by two side flaps (3, 4) each intended to form a side faces of the box. These side flaps (3, 4) are adjacent to two additional flaps (5, 6) each intended to form half of the face main opposite the main face (2). These components (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, to form a reinforcing element constituting a spacer (13) between the main faces (2, 12) of the box, as shown in figure 2.

Jumpers (22) passing through the central flap (2) hold the spacer (13) upright.

The central flap (2), forming one of the main faces, extends at the level on its short sides, by two rectangular flaps (14, 15), intended to close the ends of the box to seal it. These components (14, 15) include 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 includes elements additional (50, 51) located on the side faces (5, 6) of the box, on the side interior. These additional elements (50, 51) can be either free bands placed inside the box during its folding, or even strips glued or welded to the sheet (1) before folding. Figure 1 illustrates the sheet (1) free from these additional items. 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 resistance to stresses exerted 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). Generally, the cells of the rest of the box, except additional elements are parallel to the main direction of the main face (2, 12) to ensure good rigidity of the waiting box while retaining a minimum weight and great ease of extraction from the box.

The cellular polypropylene used has a thickness ranging from one to eight millimeters, preferably between 1.5 and 4 millimeters. Density can be variable depending on the size of the waiting box, and may vary between 150 and 1,200 grams per square meter, and preferably be between 150 and 600 grams per square meter. It is possible to use polypropylenes alveolar with different characteristics between the rest of the box and the elements additional (50, 53). Thus, additional elements made up 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 around 500 grams per square meter. The type of cells can be variable, and their section can be indifferently square, slightly rectangular or even oblique, or in inverted chevrons.

According to another characteristic of the invention, the main phase which comprises the openings (22, 23) intended to receive the metal reinforcements, may have slots (25) connecting the openings (23, 24) of the same frame, in order to facilitate its implementation. In this case, when the case is completely folded, the two flaps (5, 6) are secured by means of a long adhesive tape (28) which can advantageously extend at the level of the end (14) of the box, and further still, at the most located slot near the end of the case, as shown in Figure 9. This prevents the slot (25) in question to open under the effect of the elasticity of the feet (29) made at level of the ends of the box.

Of course, the structure of the box according to the invention can be adapted to many types of reinforcements, and in particular U-shaped reinforcements (30) comprising two arms (31) passing through the main face (2) of the box, but also the single-armatures. In this case, the reinforcement through holes are distributed also regularly, and arranged on either side of the plane of symmetry central of the box.

Depending on the desired stiffness constraints, it is possible to make vary the shape of the additional elements as illustrated for example in FIG. 3, in this case, the additional elements are in the form of a strip comprising two folds (55, 56) defining three segments (57, 58, 59). The first segment (57) comes to the side face (3). The second segment (58) comes before 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 stiffening of the box in a direction perpendicular to the main face (2), while the second segment (58) stiffens the waiting box with respect to the forces exerted perpendicular to the side 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 production of the folds (55, 56). In the case where the different segments (57, 58, 59) are produced independently, they can each be welded or glued to the faces corresponding to the box, possibly with a different orientation from their alveoli. For reasons of symmetry, two identical elements (54) are placed place in the same box.

Figures 4 to 6 illustrate an alternative embodiment in which the element additional (60) extends over the entire internal surface of the box. More specifically, the additional element (60) comprises a first segment (64) which comes to look at the main face (2) of the rest of the box. This segment (54) has openings for the passage of reinforcement, located in the same places as those provided on the main face (2). The additional element (60) includes also two lateral segments (63, 65) coming respectively with regard to the lateral faces (3, 4) of the rest of the box. Element (60) also includes two segments (62, 66) coming into contact with 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 positioning of the jumper (2) maintains contact between the segments (61, 67) of the additional element and the flaps (7, 8) of the rest of the box.

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

However, the resistance of the assembly remains satisfactory 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 reduce strongly the thickness of the cellular polypropylene used and therefore its cost price while maintaining a particularly high crush resistance.

Depending on the applications and the size, and in particular the width of the waiting box, another geometry can be adopted as illustrated in 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 FIG. 7, so as to constitute two reinforcing elements (41, 42) forming a spacer, and thus increasing the stiffness and pressure resistance of concrete during pouring.

In this case, and as illustrated in Figure 8, the box can have three additional elements (72, 73, 74). The additional elements (72, 74) are set place respectively between the lateral faces (33) and (34), and the flaps forming part of the spacer element (41, 42). The element (73) is in turn set up at the interior of the additional chute (40), and its lateral segments (75, 76) make part of the spacer elements (41, 42). We understand that the rigidity of such a box waiting is particularly important.

As already said, the orientation of the cells of the internal faces (33, 34) and of the reinforcing elements (41, 42) can be chosen to provide resistance optimal 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 adapted according to desired dimensions of the waiting box. Thus, in practice, it is possible to make boxes one to five centimeters thick and wide between five and twenty five centimeters. The step between the openings (23, 24) of reception of the reinforcements can be chosen according to the constraints of construction-specific standardization.

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

As seen in Figures 10 to 12, the extraction operation of the box after the formwork is carried out as follows. When the formwork on which was arranged the waiting boxes, has been removed, the main face of the box is flush. Just cut the adhesive tape (28) secured in the two flaps (5, 6) forming the main face (12) to unfold and separate the two flaps (5, 6), and reveal the connecting reinforcements.

After having cut the main face (2) with a sharp tool level of the reservation front, it exerts an action on the flaps (5, 6) to extract the box.

The elimination of the waiting box is extremely easy and all the more that the 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 appears from the above that the waiting box according to the invention has multiple advantages and in particular:

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

Claims (10)

Box of waiting box for the establishment of connecting reinforcements between two parts of concrete work, produced by folding a sheet (1) of foldable material, and comprising: two parallel main faces (2, 12), one of which is pierced with openings (23, 24) for the passage of the connecting reinforcements; two lateral faces (3, 4) connecting the main faces (2, 12); characterized in that: the material used to make the box is cellular polypropylene, the cells of which, at least at the main (2, 12) and lateral (3, 4) faces, are parallel to the greatest direction of the box; it includes additional elements (50, 51) also made of cellular polypropylene, at least opposite the side faces (3, 4). Box according to claim 1, characterized in that one of the main faces (12) is produced by two flaps (5, 6) of the sheet adjacent to the lateral faces (3, 4). Box according to claim 1, characterized in that at least one of the two flaps is extended by a flap (7, 8) which is folded inside the box to form a reinforcement element (13) substantially parallel to one face lateral (3, 4). Box according to claim 1, characterized in that the cells of the additional elements (50, 51) are parallel to those of the box. Box according to claim 1, characterized in that the cells of the additional elements (50, 51) are perpendicular to those of the box. Box according to claim 1, characterized in that the additional elements (50, 51) come only opposite the side faces (3, 4). Box according to claim 2, characterized in that the additional elements (54) also come opposite the flaps (5, 6) forming one of the main faces (12). Box according to claim 3, characterized in that the additional elements (54) also come opposite the reinforcing element (13). Box according to claim 8, characterized in that the additional elements (60) are connected to each other by a common face (64), located opposite the main face pierced with openings. Waiting box including a box according to one of claims 1 to 9.

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