EXPANSION JOINT WITH EASY RENOVATION FOR SYSTEM

CONCRETE SLAB FORMWORK

TECHNICAL AREA

The present invention relates to the technical field of formwork systems for concrete slabs providing an expansion joint between two adjacent slabs. The present invention relates more particularly to an improved expansion joint, in particular in terms of ease of renovation.

PRIOR ART

In the field of construction, and in particular that relating to the ground covering by concrete slabs, it is well known to use a formwork system including expansion joints between the slabs. Indeed, it is usual to divide the concrete slab into several parts, according to its surface and its thickness, to create an air space necessary for the absorption of the volume variations of a slab, for example under the action of withdrawal.

A known formwork system generally comprises an expansion joint comprising first and second longitudinal elements, arranged side by side on the same horizontal plane, and intended to each form an integral part with an upper and horizontal edge of a concrete slab. The first longitudinal element is made integral with a vertical separation plate intended to form the vertical border between the two adjacent concrete slabs. After a horizontal retraction of at least one concrete slab, the first and second longitudinal elements are separated from each other, each remaining integral with the concrete slab with which it forms an integral part.

At the end of life, or else when these formwork systems and expansion joints are incorrectly installed, the opening of the expansion joint after retraction of the concrete slabs can cause shocks or jolts leading to deterioration of the concrete and the longitudinal elements of said expansion joint.

Thus, only one solution which is sufficiently restrictive to renovate the joint consists in sawing or breaking with a jackhammer the concrete in order to be able to permanently remove the longitudinal elements from the expansion joint, and in pouring a filling material such as resin or concrete in the recess generated by the removal of joints and broken concrete.

STATEMENT OF THE INVENTION

One of the aims of the invention is therefore to remedy these drawbacks by proposing an expansion joint for a formwork system for concrete slabs, the renovation of which is simplified when damage to the longitudinal elements of the joint or of the concrete in contact with these elements have intervened.

To this end, and to solve the aforementioned problems, an expansion joint conforming to the prior art has been developed in that it comprises first and second longitudinal elements, arranged side by side on the same plane. horizontal, and intended to each form an integral part with an upper and horizontal edge of a concrete slab, preferably with the first longitudinal element made integral with a vertical separation means, such as a plate.

According to the invention, the first and second longitudinal elements comprise arrangements opening out at the level of the horizontal upper walls of said first and second longitudinal elements and making it possible to remove at least part of each of the first and second longitudinal elements for their replacement.

In this way, the damaged longitudinal elements, or poorly installed, can be removed by acting on the arrangements which are accessible after pouring and drying of the concrete slabs, and replaced. The heavy operations of breaking the concrete and the joints for their forced removal are eliminated. Renovation is quick and easy.

According to a particular embodiment, the second longitudinal element consists of at least two parts fixed to each other by fixing means

removable, so that only the removable part is removed and replaced during the renovation. The other part remains fixed and anchored in concrete.

According to particular embodiments, in order to be able to be removed and replaced, the first longitudinal element is either fixed to the vertical separation plate by removable fixing means, or it also consists of at least two parts fixed one on the other by removable fixing means, with a removable upper part and a lower part secured to the separation plate.

Preferably, the vertical plane defined by the separation plate is offset horizontally relative to the vertical plane defined between the first and second longitudinal elements. Thus, when the concrete slabs retract, the longitudinal elements move away from each other, but always remain in abutment on one of the concrete slabs. The joint stability is optimal and the appearance of disorders, such as cracks or breaks is reduced.

Advantageously, the first and second longitudinal elements comprise complementary means for fitting horizontally into one another. Thus, the horizontal nesting allows a transfer of vertical loads between the first and second longitudinal elements of the expansion joint.

For example, the first longitudinal element comprises a stack of three layers of material, with an intermediate layer which is narrower than the other two layers so as to have a U-shaped cross section, and the second longitudinal element comprises a stack of three layers of complementary material, with an intermediate layer wider than the other two layers so as to form a transverse projection capable of fitting into the hollow of the U-shape of the first longitudinal element.

According to a particular embodiment, the arrangements are in the form of orifices vertically passing through at least the removable part of each of the first and second longitudinal elements, and of rods inserted into said orifices with lower ends integral with a fixed part expansion joint and

threaded upper ends capable of receiving clamping members for the removable fixing of said removable part of each of the first and second longitudinal elements.

Preferably, the removable parts of the first and second longitudinal elements have facing faces comprising complementary sinusoidal profiles to ensure continuity at the level of the separation between two concrete slabs. Thus, during the passage of a wheeled vehicle, said wheels always remain supported by the surface of one of the adjacent slabs. This characteristic makes it possible to limit shock and wear of the concrete slabs near the expansion joints.

According to another characteristic of the invention, at least the removable part of each of the first and second longitudinal elements is made of a polymer material, or of a composite material made from a polymer material, such as plastic, resin, etc. This characteristic allows, when the longitudinal elements of the expansion joint have a vertical offset, causing shocks and jolts during the passage of vehicles, to be able to sand said longitudinal elements to achieve optimal planimetry. The renovation is very quick and simply consists of a sanding step.

Of course, the sandable nature of the longitudinal elements is independent of the removable nature so that it may be envisaged to develop a remarkable expansion joint in that it comprises first and second longitudinal elements made of a polymer material, or in a composite material produced from a polymer material, without, however, having a removable character.

SUMMARY DESCRIPTION OF FIGURES

Other advantages and characteristics will emerge more clearly from the description which follows of several variant embodiments, given by way of nonlimiting examples, of the expansion joint according to the invention, with reference to the appended drawings in which:

Figure 1 is a perspective view illustrating an embodiment of the expansion joint according to the invention, before shrinking the concrete slabs;

Figure 2 is a perspective view similar to that of Figure 1, after retraction of the concrete slabs;

Figure 3 is a cross-sectional representation of the embodiment of the expansion joint illustrated in Figure 1, before shrinking the concrete slabs;

- Figure 4 is a cross-sectional representation of the embodiment of the expansion joint illustrated in Figure 2, after shrinking the concrete slabs.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to an expansion joint (1) for a concrete slab formwork system which employs at least one means of vertical separation of two adjacent concrete slabs, for example a plate, and which is used when it is necessary, for pouring concrete, to divide the concrete slab into several parts, according to its surface and its thickness, to create an air space necessary for the absorption of the variations in volumes of a slab, for example under the action of withdrawal.

Referring to Figures 1 to 4, the expansion joint (1) comprises first and second longitudinal elements (2, 3), arranged side by side on the same horizontal plane, and intended to each form an integral part with an upper edge and horizontal view of a concrete slab.

The first longitudinal element (2) is preferably made integral with a vertical separation means (4) of the two adjacent slabs, for example a plate. The vertical separation means can be directly fixed, for example welded, under the first longitudinal element, or else the first longitudinal element (2) can come to rest on a vertical separation element already present between the two slabs.

The first and second longitudinal elements (2, 3) can be made of metal, or else of a material suitable for being sanded, such as a polymer or a composite material made from a polymer, for example plastic or resin.

Thus, when the expansion joint is damaged or improperly installed, and the longitudinal elements (2, 3), which form the upper edges of the slabs, are offset

vertically, shocks and jolts occur during the passage of wheeled vehicles, causing disorders in the concrete and accelerated deterioration of the concrete and the expansion joint (1).

The sandable nature of the longitudinal elements (2, 3) makes it possible to be able to level said longitudinal elements (2, 3) by a sanding operation and to obtain an optimal planimetry of the expansion joint (1) and of the concrete slabs. Thus, the renovation of the expansion joint (1) is facilitated.

The invention also makes it possible to remedy this problem by the following characteristics, taken alone or in combination with the sandable nature of the longitudinal elements (2, 3), according to which said longitudinal elements (2, 3) include arrangements, opening out at the level horizontal upper walls of said first and second longitudinal elements (2, 3), and making it possible to remove at least one part (2a, 3a) from each of the first and second longitudinal elements (2, 3) for their replacement.

According to a preferred embodiment, the first longitudinal element (2) comprises a stack of three layers of material, including an upper layer (2a), an intermediate layer (2b), and a lower layer (2c). The intermediate layer (2b) has a width less than that of the upper (2a) and lower (2c) layers so that the first longitudinal element (2) has a U-shaped cross section.

Similarly, the second longitudinal element (3) comprises a stack of three layers of complementary material, including an upper layer (3a), an intermediate layer (3b), and a lower layer (3c) whose width is greater. than that of the upper (3 a) and lower (3 c) layers so as to form a transverse projection capable of fitting into the hollow of the U shape of the first longitudinal element (2) and allowing the transfer of vertical loads.

The upper layers (2a) and (3a) may each comprise a surface layer of a polymeric material as mentioned.

The first and second longitudinal elements (2, 3) include orifices (5) formed in their thickness so as to pass vertically through all of the three layers (2a, 2b, 2c, 3a, 3b, 3c). These orifices (5) are capable of receiving insertion rods (6) fixed at their lower ends to fixed parts of the expansion joint (1). For example, the lower ends of the rods (6) are welded to the lower layers (2c, 3c) of the first and second longitudinal elements (2, 3). The lower ends of the rods (6) can also be fixed to fixed parts of the formwork system on which the expansion joint is mounted without departing from the scope of the invention. The upper ends of the rods (6) do not project from the first layers (2a, 3 a) of the first and second longitudinal elements (2, 3), and are, for example, threaded to cooperate with clamping members (7) for locking in position, at least the upper layers (2a, 3a) of the first and second longitudinal elements (2, 3). Conversely, when these clamping members (7) are unscrewed, the upper layers (2a, 3 a) of said first and second longitudinal elements (2, 3) can be removed and replaced, in particular when they are damaged or else when a vertical offset generating shocks and jolts is felt when a vehicle passes. Of course, the threaded rods (6) can be replaced by threaded sockets to cooperate with threaded clamping members (7) without departing from the scope of the invention. at least the upper layers (2a, 3a) of the first and second longitudinal elements (2, 3). Conversely, when these clamping members (7) are unscrewed, the upper layers (2a, 3 a) of said first and second longitudinal elements (2, 3) can be removed and replaced, in particular when they are damaged or else when a vertical offset generating shocks and jolts is felt when a vehicle passes. Of course, the threaded rods (6) can be replaced by threaded sockets to cooperate with threaded clamping members (7) without departing from the scope of the invention. at least the upper layers (2a, 3a) of the first and second longitudinal elements (2, 3). Conversely, when these clamping members (7) are unscrewed, the upper layers (2a, 3 a) of said first and second longitudinal elements (2, 3) can be removed and replaced, in particular when they are damaged or else when a vertical offset generating shocks and jolts is felt when a vehicle passes. Of course, the threaded rods (6) can be replaced by threaded sockets to cooperate with threaded clamping members (7) without departing from the scope of the invention. 3 a) of said first and second longitudinal elements (2, 3) can be removed and replaced, in particular when they are deteriorated or when a vertical offset generating shocks and jolts is felt when passing a vehicle. Of course, the threaded rods (6) can be replaced by threaded sockets to cooperate with threaded clamping members (7) without departing from the scope of the invention. 3 a) of said first and second longitudinal elements (2, 3) can be removed and replaced, in particular when they are deteriorated or when a vertical offset generating shocks and jolts is felt when passing a vehicle. Of course, the threaded rods (6) can be replaced by threaded sockets to cooperate with threaded clamping members (7) without departing from the scope of the invention.

The width of the upper layer (2a) of the first longitudinal element (2) is greater than the width of the upper layer (3 a) of the second longitudinal element (3), and the lower layer (2c) of the first longitudinal element ( 2) is made integral with the vertical separation plate (4), for example by welding, so that the vertical plane defined by the separation plate (4) is offset horizontally relative to the vertical plane (P) defined between the first and second longitudinal elements (2, 3). Thus, with reference to Figures 2 and 4, when the concrete slabs retract, the longitudinal elements (2, 3) move away from each other but always remain in abutment on one of the concrete slabs. The stability of the joint is optimal and the appearance of disorders,

The invention therefore describes an expansion joint (1) comprising first and second longitudinal elements (2, 3) each having removable parts, constituted in particular by the upper layers (2a, 3 a).

Other embodiments can be imagined without departing from the scope of the invention. For example, the intermediate (2b, 3b) and lower (2c, 3c) layers of the first and second longitudinal elements (2, 3) can form a monobloc assembly, or else the first longitudinal element (2) can be made in one part fixed removably directly, by the same means as above, on the vertical separation plate (4) provided for example with an upper flange at right angles.

In order to ensure continuity at the level of the separation between the two concrete slabs, the removable parts of the first and second longitudinal elements (2, 3), in particular the upper layers (2a, 3a), have facing faces comprising complementary sinusoidal profiles. Thus, during the passage of a vehicle, the wheels always remain supported by the surface of one of the adjacent slabs. This characteristic makes it possible to limit shock and wear of the concrete slabs near the expansion joints.
CLAIMS

1 - Expansion joint (1) for a concrete slab formwork system, said joint comprising first and second longitudinal elements (2, 3), arranged side by side on the same horizontal plane, and intended to each form an integral part with an upper and horizontal edge of a concrete slab, the first and second longitudinal elements (2, 3) comprise arrangements (5, 6, 7) opening out at their horizontal upper walls and making it possible to remove at least part ( 2a, 3a) of each of the first and second longitudinal elements (2, 3) for their replacement, characterized in that the first longitudinal element (2) comprises a stack of three layers of material (2a, 2b, 2c), with a intermediate layer (2b) comprising a width less than that of the other two layers (2a,2c) so that the first longitudinal element (2) has a U-shaped cross section, and the second longitudinal element (3) comprises a stack of three layers of complementary material (3a, 3b, 3c), with a intermediate layer (3b) comprising a width greater than that of the other two layers (3a, 3c) so as to form a transverse projection capable of fitting into the hollow of the U-shape of the first longitudinal element (2) .3 c) so as to form a transverse projection capable of fitting into the hollow of the U-shape of the first longitudinal element (2).3 c) so as to form a transverse projection capable of fitting into the hollow of the U-shape of the first longitudinal element (2).

2 - Expansion joint (1) according to claim 1, characterized in that the second longitudinal element (3) consists of at least two parts (3a, 3b, 3c) fixed to one another by means removable fasteners (6, 7).

3 - Expansion joint (1) according to claim 2, characterized in that the first longitudinal element (2) is fixed to a means (4) of vertical separation (4) between the concrete slabs.

4 - Expansion joint (1) according to claim 2, characterized in that the first longitudinal element (2) consists of at least two parts (2a, 2b, 2c) fixed to one another by means removable fasteners (6, 7).

5 - Expansion joint (1) according to claim 3, characterized in that the vertical plane defined by the separation means (4) is horizontally offset from the vertical plane (P) defined between the first and second longitudinal elements (2 , 3).

6 - Expansion joint (1) according to one of the preceding claims, characterized in that the arrangements are in the form of orifices (5) vertically passing through at least the removable part (2a, 3a) of each of the first and second longitudinal elements (2, 3), and rods (6) inserted in said orifices (5) with lower ends secured to a fixed part of the expansion joint (1) and upper threaded ends capable of receiving organs of clamping (7) for the removable fixing of said removable part (2a, 3a) of each of the first and second longitudinal elements (2, 3).

7 - Expansion joint (1) according to one of the preceding claims, characterized in that the removable parts (2a, 3 a) of the first and second longitudinal elements

(2, 3) have facing faces comprising complementary sinusoidal profiles.

8 - Expansion joint (1) according to one of the preceding claims, characterized in that at least the removable part (2a, 3a) of each of the first and second longitudinal elements (2, 3) is made of a polymer material , or in a composite material made from a polymer material.