FR3101092A1 - Formwork element and method of constructing a concrete structure in a cavity - Google Patents

Abstract

The invention relates to a formwork element and a method of constructing a concrete structure in a cavity. The formwork element according to the invention is intended for the construction of a vertical wall of a concrete structure intended to contain a liquid. The shuttering element (100) includes a first shuttering panel (110) of perforated metal sheet, a second shuttering panel (120) of fiber cement, and a plurality of spacers (130). The formwork element (100) can be used reversibly in the construction process. The construction process makes it possible to obtain a one-piece, undeformable, reinforced concrete structure which does not risk cracking. In addition, the upper level of the walls can be easily widened to support the copings, without risk of cracks and / or breakage. In addition, the structure is scalable by being compatible with any finish coating. Figure to be published with the abstract: figure 7

Description

Formwork element and method of constructing a concrete structure in a cavity

The invention relates to a formwork element and a method for constructing a concrete structure in a cavity.

A classic poured concrete structure intended to contain a liquid, and in particular a swimming pool, comprises on the one hand a raft (which forms the bottom of the structure) and generally vertical walls. Given its purpose, such a structure must be perfectly waterproof.

Conventionally, such a structure can be sealed by applying a polyvinyl chloride (PVC) tarpaulin, known as a "liner". A liner completely covers the faces of the structure, called inner faces, facing the inside of the structure and is intended to be in contact with the liquid.

However, it is known that the liners have a very low tear resistance, which requires to replace them completely in case of damage.

Given this state of the art, the inventor has determined that it could be advantageous to have a method of constructing a concrete structure which is waterproof ab initio and does not require the use of liner to be waterproof.

The invention aims to overcome this drawback.

Thus, the invention relates to a formwork element.

The invention also relates to a method of constructing a concrete structure in a cavity.

To this end, the invention proposes a formwork element for the construction of a vertical wall of a concrete structure intended to contain a liquid.

The formwork element has internal faces and external faces which are respectively oriented towards the inside and the outside of the formwork element.

The formwork element includes:
- a first shuttering panel in perforated metal sheet,
- a second fiber cement formwork panel, and
- spacers fixed to the internal faces to keep the shuttering panels parallel to each other and at a distance from each other.

Furthermore, the formwork element comprises at its lower end, a lower opening made in one of the external faces, called the first external face, and through which the concrete can discharge when the formwork element is installed in position. vertical.

In addition to the characteristics mentioned in the previous paragraphs, the formwork element may have one or more additional characteristics among the following, considered individually or according to the possible technical combinations.

In a particular implementation, the lower opening extends over the entire width of the first external face.

In another particular implementation, the spacers are articulated between a folded transport position in which the internal faces are pressed against each other and a deployed position of use in which the internal faces are parallel to each other and to distance from each other.

According to a particular embodiment, the internal faces each comprise a plurality of stiffeners, into which the plurality of spacers fit.

According to another particular embodiment, the formwork element further comprises
- at its upper end, an upper opening made in the other of the external faces, called the second external face, and
- a third panel in perforated metal sheet, which is folded at least in two parts, called first part and second part, the first part and the second part each comprising an internal face and an external face.

Furthermore, the third panel is fixed on the second external face so that the external faces of the first part and of the second part are oriented towards the outside of the formwork element and so as to:
- flatten the internal face of the first part, substantially below the upper opening, and
- Arrange the second part, substantially at the level of the upper opening to form a predetermined acute angle between the internal face of the second part and a plane containing the upper opening.

Preferably, the upper opening extends over all or part of the width of the second external face.

According to one implementation, the formwork element further comprises a plurality of horizontal stiffeners fixed to the upper level of the second external face and to at least one side of the second part.

The invention also proposes a method of constructing a concrete structure in a cavity, the structure being intended to contain a liquid.

The method according to the invention comprises the following steps:
- providing a plurality of formwork elements according to the embodiments above,
- vertically juxtaposing the plurality of formwork elements on a seating surface of the cavity, so as to orient the first openings towards the interior of the cavity,
- arranging first reinforcements inside the plurality of formwork elements,
- arranging second frames on the seating surface of the cavity, so as to insert all or part of the ends of the second frames into the lower openings,
- pouring fresh concrete, first, inside the plurality of formwork elements, with a view to producing the walls of the structure, and
- Pouring fresh concrete, then, on the seating surface of the cavity, in order to make the slab, while the concrete inside the plurality of formwork elements is still fresh.

In a particular implementation, the method further comprises the following step, when the first external faces of the plurality of formwork elements are made of fiber cement:
- Applying a first layer of a first liquid sealing membrane on the outer faces of each of the plurality of shuttering panels, so that the first liquid membrane forms a first sealed shell on drying.

In another particular implementation, the method further comprises the following step:
- Applying a second layer of a second liquid sealing membrane to the first waterproof shell, so that the second liquid membrane forms a second waterproof shell on drying.

According to a particular embodiment, the first liquid membrane and the second liquid membrane are applied in crossed layers.

According to another particular embodiment, the first liquid sealing membrane is different from the second liquid sealing membrane.

According to yet another particular embodiment, a finishing coating is applied to the first sealed shell or to the second sealed shell.

Other aims, characteristics and advantages of the invention will appear on reading the following description, which refers to the appended figures which represent preferred embodiments of the invention, which are given solely by way of examples. not limiting.

FIG. 1 represents a formwork element according to the invention, in the installation position on a seating surface of a cavity.

Figure 2 shows the third formwork panel of the formwork element of figure 1.

Figure 3 shows a side view of the third formwork panel of Figure 2.

Figure 4 shows the shuttering panel of Figure 2 when it is installed on the shuttering element of Figure 1.

Figure 5 shows the arrangement of Figure 4 with the fixing of stiffeners on the top level of the formwork element.

Figure 6 shows the arrangement of figure 4 with the fixing of stiffeners on the third formwork panel of figure 2.

Figure 7 shows a method of constructing a concrete structure in a cavity.

Figure 8 shows a typical arrangement of a coping on a wall of a liquid retention basin.

FIG. 9 represents a conventional arrangement of a coping on a wall of a liquid retention basin obtained according to an implementation of the invention.

The figures do not necessarily respect the scales, in particular in thickness, and this for purposes of illustration.

The formwork element according to the invention is intended for the construction of a vertical wall of a concrete structure intended to contain a liquid.

In one example, the structure is a swimming pool and the liquid is water. However, the invention also covers any liquid retention basin and any liquid adapted to be contained in the liquid retention basin.

In the rest of the description, the terms "upper", "lower", "high" and "lower", refer to the layout of the formwork element in the figures, which generally corresponds to its installation layout on a seating surface of a cavity. By seating surface is meant the bottom of the cavity which is generally flat and horizontal.

In general, the formwork element is designed to be installed in a vertical position. In addition, it has internal faces and external faces which are respectively oriented towards the inside and the outside of the formwork element. In addition, the formwork element is configured to allow concrete to be poured into its interior from its upper part.

In figure 1, the formwork element 100 comprises a first formwork panel 110, a second formwork panel 120 and a plurality of spacers 130.

In the example of Figure 1, the first shuttering panel 110 is made of perforated metal sheet.

In another example, the first shuttering panel 110 is of the same type as those marketed under the brand Metal deployed, namely, a sheet perforated by the multiple incisions, in staggered rows, of a sheet of metal, then by extension in order to open these incisions.

In this example, the formwork panel 110 may have openings less than or equal to 16 mm by 7 mm for a thickness greater than or equal to 1 mm, or have openings less than or equal to 28 mm by 9 mm for a thickness greater than or equal to at 1.5mm. However, the invention also covers other dimensions without requiring modifications of the principles of the invention.

In a particular implementation, the first formwork panel 110 has an internal face and an external face which are respectively oriented towards the inside and the outside of the formwork element 100. Thus, the internal face and the external face of the first formwork panel 110 correspond respectively to one of the internal and external faces of the formwork element 100.

In another particular implementation, the first shuttering panel 110 is made of galvanized steel to protect the steel against oxidation.

The first shuttering panel 110 thus configured allows the concrete to spread and to transpire slightly through the openings so as to limit the thrust forces undergone by the second shuttering panel 120.

In the example of Figure 1, the second formwork panel 120 is made of fiber cement, namely, a prefabricated material consisting of very fine fibers held together by a cement binder.

This material is advantageous because it is water resistant and unalterable by the humidity and the laitance brought by the poured concrete during the construction of the structure, nor later by the liquid contained in the structure. Moreover, with the construction process that will be described below, it will be shown that this material does not need to be covered with a finishing coating, such as polyvinyl chloride (PVC) tarpaulins called "liners". in English, to make the structure waterproof.

In one example, the second formwork panel 120 is of the same type as those marketed under the Fibrociment brand and has a thickness of approximately 1 cm. However, the invention also covers other types of products and other dimensions without requiring modifications of the principles of the invention.

In a particular implementation, the second formwork panel 120 has an internal face and an external face which are respectively oriented towards the inside and the outside of the formwork element 100. Thus, the internal face and the external face of the second formwork panel 120 correspond respectively to one of the internal and external faces of the formwork element 100.

In practice, the external face of the second formwork panel 120 is solid, flat and smooth, which is not necessarily the case for the internal face of the second formwork panel 120.

In the example of Figure 1, spacers 130 are fixed to the internal faces of the formwork element 100 to maintain the first formwork panel 110 and the second formwork panel 120 parallel to each other and at a distance from each other. .

In one example, the struts 130 have a thickness of at least 15 cm to seal the structure. However, the invention also covers other dimensions without requiring modifications of the principles of the invention.

In a particular implementation, the spacers 130 are articulated between a folded transport position in which the internal faces of the formwork element 100 are pressed against each other and a deployed position of use in which the faces internal of the formwork element 100 are parallel to each other and at a distance from each other.

In this implementation, an articulation mechanism of a known type can be used.

In another particular implementation, spacers 130 include anchor heads to fit into stiffeners 103.

In this particular implementation, the internal faces of the formwork element 100 each comprise a plurality of stiffeners 103 in which the anchor heads of the plurality of spacers 130 fit.

In one example, the stiffeners 103 are formed by galvanized steel rails so that they have a U-shaped section. The stiffeners 103 comprise a web, two flanges which extend along the side edges of the web, and two wing returns that extend the wings so that the wing returns extend in a plane parallel to the plane of the web.

In this example, the stiffeners 103 are fixed to the internal faces of the formwork element 100 by screws and are arranged so as to extend vertically when the formwork element 100 is in the installation position.

The stiffeners 103 have a predetermined length so that they project from the bottom of the first shuttering panel 110 or from the second shuttering panel 120 and delimit a lower opening 101 which allows the passage of concrete.

In other words, the formwork element 100 comprises at its lower end, the lower opening 101 which is made in one of its external faces, called the first external face, and through which the concrete can discharge.

In one example, the lower opening 101 extends over the entire width of the first outer face.

This arrangement has the effect of making the formwork element 110 reversible, in particular in its use in the construction process which will be described below. Thus, the formwork element can be oriented in the direction that one wishes, as long as the lower opening 101 is provided at the bottom of the formwork element 100.

Indeed, in a first example, the first external face corresponds to the external face of the first shuttering panel 110. This configuration makes it possible to obtain a wall with good metal grip which is appropriate for certain types of coverings. These are, for example, coatings of the undercoat type (conventional mortar) or finishing coats applied in thickness (for example, about 2.5cm).

On the other hand, in a second example, the first external face corresponds to the external face of the second formwork panel 120. This configuration makes it possible to obtain a wall suitable for all types of finishing coating such as "liners", tiling or paint.

In an optional implementation, given the example of Figure 1, the formwork element 100 also comprises at its upper end, an upper opening 102 made in the other of the outer faces of the formwork element 100 , called the second external face.

Thus, due to the reversibility of the shuttering element 100, if the lower opening 101 is made in the first shuttering panel 110 then the upper opening 102 will be made in the second shuttering panel 120. On the contrary, if the opening opening 101 is made in the second shuttering panel 120 then the upper opening 102 will be made in the first shuttering panel 110.

In one example, the upper opening 102 extends over all or part of the width of the second outer face. For example, in figure 1, the upper opening 102 corresponds to a cutout of the second formwork panel around the stiffeners 103.

In this optional implementation, the shuttering element 100 also comprises a third shuttering panel 140 made of perforated metal sheet of the same type as the first shuttering panel 110. However, as illustrated in FIG. 2, the third shuttering panel 140 is substantially narrower than the first shuttering panel 110.

In a particular implementation, the width of the third formwork panel 140 is less than approximately one third of the width of the first formwork panel 110, preferably less than half the width of the first formwork panel 110.

Furthermore, as illustrated in Figure 3, the third formwork panel 140 is folded at least into two parts, called the first part 131 and second part 132. The first part 131 and the second part 132 each comprise an internal face and an external face. .

In this optional implementation, as illustrated in Figure 4, the third panel 140 is attached orthogonally to the second outer face, so that the outer faces of the first part 131 and the second part 132 face outwards. of the formwork element 100, so as to flatten the internal face of the first part 131, substantially below the upper opening 102 and so as to arrange the second part 132, substantially at the level of the upper opening 102 to form a predetermined acute angle α between the internal face of the second part 132 and a plane which contains the upper opening 102.

In one example, the first part 131 is fixed on the second external face by screws on the stiffeners 103 mounted on the first shuttering panel 110.

In another example, the acute angle α is between approximately 0° and approximately 90°, preferably between approximately 30° and approximately 50°.

This optional implementation has the effect of allowing the widening of the upper level of the concrete wall according to the desired dimension L so that it can support copings, often in natural or reconstituted stone, without risk of cracks and/or breakage. This wider upper level can be reinforced by arranging reinforcements in the space created.

Indeed, the circumference of a liquid retention basin generally includes copings which separate the basin from a terrace formed around the swimming pool. As illustrated in FIG. 8, in the prior art, a coping 300 rests partly on the upper level of a wall 400 of the liquid retention basin and partly on the embankment 500 which is on the side of the ground in place 600, because the width of the 300 coping is greater than that of the 400 wall. Indeed, the width of a 300 coping is generally from twenty-five to thirty-five centimeters, while the width of the 400 wall is l order of 15 cm. However, over time, the embankment 500 sags and the coping 300 is then cantilevered with the risk of cracking and/or breaking. Thus, as illustrated in figure 9, the solution according to the invention makes it possible to better support copings of the coping type 300.

In an example of this optional implementation, as illustrated in FIGS. 5 and 6, the formwork element 100 further comprises a plurality of horizontal stiffeners 104 fixed to the upper edge of the second external face and to at least one side of the second part 131.

In one example, the horizontal stiffeners 104 are fixed to the upper level of the second external face and to one of the sides of the second part 131 by screws. For example, one of the sides of the second part 131 can be the upper side and/or a side side.

The invention also covers a method of constructing 200 a concrete structure in a cavity.

In one example, the cavity is an excavation made in the ground.

In another example, the cavity is a reservoir of an existing impoundment. This arrangement has the effect of allowing the renovation of the existing damaged retention pond without requiring excavation or the removal or dismantling of the existing retention pond.

In step 210, called supply, a plurality of formwork elements 100 as described above are supplied.

In step 220, called juxtaposition, the plurality of formwork elements are vertically juxtaposed on a seating surface of the cavity, so as to orient the first openings 101 towards the interior of the cavity.

In step 230, called the first arrangement step, first reinforcements are arranged inside the plurality of formwork elements 100.

In step 240, called second arrangement, second frames are arranged on the seating surface of the cavity, so as to insert all or part of the ends of the second frames into the lower openings 101.

The arrangement of the first frames and the second frames is of the type known in the field of civil engineering. Furthermore, the two arrangements can be made at the same time.

In step 250, called the first pour, fresh concrete is first poured inside the plurality of formwork elements 100, with a view to producing the walls of the structure.

By fresh concrete, we mean the state of the concrete when it has not begun its process of setting and hardening.

The first casting has the effect that the concrete disgorges through the lower openings 101.

In step 260, called second pouring, fresh concrete is then poured onto the seating surface of the cavity, with a view to making the slab, while the concrete inside the plurality of elements formwork is still fresh.

The second casting has the effect that the concrete poured on the seating surface mixes with the concrete which flows out of the openings 101, to form a one-piece shuttered reinforced concrete structure, non-deformable and which does not risk cracking.

Conventionally, the concrete is pulled over the upper face of the slab to obtain a flat and smooth surface.

In one example, the slab is made to have a thickness of at least 15 cm to ensure the watertightness of the structure. However, the invention also covers other dimensions without requiring modifications of the principles of the invention.

In a particular implementation, the method further comprises a step 270, called first application, in which, when the first external faces of the plurality of formwork elements 100 are made of fiber cement, a first layer of a first liquid sealing membrane on the outer faces of each of the plurality of shuttering panels 100, so that the first liquid membrane forms a first watertight shell on drying.

In this particular implementation, the method further comprises a step 280, called second application, in which a second layer of a second liquid sealing membrane is applied to the first waterproof shell, so that the second liquid membrane forms a second watertight shell as it dries.

In one example, the first liquid membrane and the second liquid membrane are applied in crossed layers, namely, alternately in one direction, then in a perpendicular direction.

The application of a liquid membrane reinforces the tightness of the structure, because it adheres to the fiber cement material by blocking all or part of the pores of the material.

The application in cross layers is suitable to allow the longitudinal and transverse placement of the fibers of the second formwork panel 120.

In another example, the first liquid sealing membrane is different from the second liquid sealing membrane.

One can use, as it is, the structure thus obtained without the application of a liner, because it is sealed ab initio .

Indeed, the combination of a veil of concrete, a fiber cement panel and a liquid membrane prevents the migration of water from the exterior of the structure to its interior. This migration water is usually rainwater that migrates into the fill that surrounds the structure. This phenomenon of migration corresponds to more than 50% of water retention basin claims. However, the use of a liner as a waterproofing system does not prevent this phenomenon. On the contrary, in this case, unsightly pockets of water tend to form.

Furthermore, with the structure according to the invention, the impoundment is immediate, unlike structures which require the use of a liner, for which the liner must first be manufactured in the factory according to the measurements of the structure.

In yet another example, a finishing coating is applied to the first waterproof shell or to the second waterproof shell, such as "liners", tiling or paint. In this way, the structure according to the invention is scalable, because any finishing coating can be applied later. For example, years later after applying the liquid membrane.

Claims (13)

Formwork element (100) for the construction of a vertical wall of a concrete structure intended to contain a liquid, the formwork element having internal faces and external faces which are respectively directed towards the interior and the exterior of the formwork element, the formwork element comprising:
- a first shuttering panel (110) in perforated metal sheet,
- a second formwork panel (120) in fiber cement, and
- spacers (130) fixed to the internal faces to maintain the formwork panels parallel to each other and at a distance from each other,
in which the formwork element comprises at its lower end, a lower opening (101) made in one of the external faces, called the first external face, and through which the concrete can discharge when the formwork element is installed in a vertical position. Formwork element according to Claim 1, in which the lower opening (101) extends over the entire width of the first external face. Formwork element according to any one of Claims 1 to 2, in which the spacers (130) are articulated between a folded transport position in which the internal faces are pressed against each other and a deployed position for use in which the internal faces are parallel to each other and at a distance from each other. Formwork element according to any one of Claims 1 to 3, in which the internal faces each comprise a plurality of stiffeners (103), into which the plurality of spacers (130) fit. Formwork element according to any one of Claims 1 to 4, further comprising
- at its upper end an upper opening (102), made in the other of the outer faces, called the second outer face, and
- a third panel (130) in perforated metal sheet, which is folded in at least two parts, called the first part and the second part, the first part and the second part each comprising an internal face and an external face,
in which the third panel is fixed on the second external face so that the external faces of the first part and of the second part are oriented towards the outside of the formwork element and so as to:
- flatten the internal face of the first part, substantially below the upper opening, and
- Arrange the second part, substantially at the level of the upper opening (102) to form a predetermined acute angle between the internal face of the second part and a plane containing the upper opening. Formwork element according to Claim 5, in which the upper opening (102) extends over all or part of the width of the second external face. Formwork element according to any one of Claims 5 to 6, further comprising a plurality of horizontal stiffeners (104) fixed to the upper edge of the second external face and to at least one side of the second part. A method (200) of constructing a concrete structure in a cavity, the structure being intended to contain a liquid, the method comprising the following steps:
- providing (210) a plurality of formwork elements according to any one of claims 1 to 7,
- vertically juxtaposing (220) the plurality of formwork elements on a seating surface of the cavity, so as to orient the lower openings (101) towards the interior of the cavity,
- arranging (230) first reinforcements inside the plurality of formwork elements,
- arranging (240) second frames on the seating surface of the cavity, so as to insert all or part of the ends of the second frames into the lower openings (101),
- pouring (250) fresh concrete, first, inside the plurality of formwork elements, with a view to producing the walls of the structure, and
- Pouring (260) fresh concrete, then, on the seating surface of the cavity, with a view to producing the slab, while the concrete inside the plurality of formwork elements is still fresh. A method according to claim 8, further comprising the following step, when the first outer faces of the plurality of formwork elements are of fiber cement:
- applying (270) a first layer of a first liquid sealing membrane on the outer faces of each of the plurality of shuttering panels, so that the first liquid membrane forms a first watertight shell on drying. A method according to claim 9 further comprising the following step:
- applying (280) a second layer of a second liquid sealing membrane on the first sealed shell, so that the second liquid membrane forms a second sealed shell on drying. Process according to Claim 10, in which the first liquid membrane and the second liquid membrane are applied in crossed layers. A method according to any one of claims 10 to 11 wherein the first sealing liquid membrane is different from the second sealing liquid membrane. Process according to any one of Claims 10 to 12, in which a finishing coating is applied to the first sealed shell or to the second sealed shell.