WO2007079989A1

WO2007079989A1 - Formwork panel

Info

Publication number: WO2007079989A1
Application number: PCT/EP2006/065529
Authority: WO
Inventors: Pierre Messiqua; Régis Messiqua
Original assignee: Polyfinance Coffor Holding S.A.
Priority date: 2006-01-12
Filing date: 2006-08-21
Publication date: 2007-07-19

Abstract

The invention aims at reducing production costs and rationalizing factory mass production of formwork panels while providing maximum strength to the walls or slabs built with this type of formwork. This is achieved by a formwork panel (1) for concrete walls and slabs comprising a wire mesh metal sheet (2) reinforced with a plurality of stiffeners (3) consisting of rigid profiled metal bars secured to one side of said sheet arranged mutually parallel and spaced apart at predetermined intervals, and with ribs (4) integrated to the wire mesh of the sheet (2) spaced apart at predetermined intervals and intersecting the stiffeners. The wire mesh sheet (2) is fixed on the stiffeners (3) by crimping at least at one intersection between the ribs (4) and the stiffeners. The panel (1) is characterized in that the crimping is performed such that at least one portion of the metal of the rib (4) supports the stiffener (3) by passing through a corresponding hole (5) of the stiffener.

Description

PANEL FOR FORMWORK

Field of the invention

The present invention relates to the field of formwork for the construction of a wall or slab of concrete or similar material. More specifically, it refers to the formwork walls or shuttering panels that constitute the formwork itself. In the case of a wall, the form is formed by panels arranged vertically and parallel to each other. They can be connected by a connecting device creating a space to be filled with a material such as concrete.

A panel can be arranged vertically against a wall to form a simple formwork. It can also be used as a base for the construction of a slab.

A panel comprises a screen sheet extending on profiled vertical bars generally U integral with the mesh. These bars called stiffeners are spaced at predefined intervals on the sheet.

Such a formwork system is generally used as a formwork lost or integrated that is to say that it remains as an integral part of the wall after pouring the concrete in the space between the two panels.

Technical background

The documents EP0883719 and WO02 / 38878 disclose a formwork comprising an outer wall and an inner wall, these walls, called formwork walls, comprise vertical stiffeners consisting of generally U-shaped profiled bars. The formwork walls are connected by devices each consisting of a bent bar substantially zig-zag and articulated at the stiffeners. These devices maintain a determined space between the formwork walls in which the concrete is poured.

The document WO03 / 010397 describes the formwork of the documents cited above where reinforcement elements are introduced between the lateral sides of the U-shaped sections of two stiffeners placed opposite each wall. Each reinforcing element comprises at least one vertical bar and at least two sleepers horizontally adjusted to slide inside the profile of the stiffeners. This reinforcement element is added after the deployment of the formwork walls by sliding in the stiffeners which act as guide rails. The U-shape of these stiffeners ensures the maintenance and stability of this frame member while facilitating its insertion.

WO2005042864 discloses a high strength concrete wall formwork having two parallel formwork walls placed opposite each other provided with profiled bars forming vertical stiffeners. The walls are connected by an articulated connection device for maintaining the formwork walls at a spacing defining a space for receiving a filling material such as concrete. The articulation of the connecting device makes it possible to fold the formwork for storage and transport. The connecting device comprises a pair of horizontal straight bars parallel to the formwork walls. The bars placed one opposite the other through the stiffeners of the respective walls. The connecting device also comprises a plurality of connecting bars perpendicularly connecting the two horizontal bars around which they articulate.

The formwork with its two formwork walls equipped with stiffeners and assembled with the connecting devices are prefabricated at the factory. It is transported to the construction site in folded form thanks to the joints of the connecting elements on the stiffeners. The advantage of such a formwork is its maneuverability and speed of assembly on site with a minimum of tools and labor. In order to minimize the overall construction costs and to ensure a high quality of the erected walls, each step of the formwork manufacture must be optimized both in speed of execution and reliability of the components or the finished product. An important component here is the formwork wall or the formwork panel designed to withstand the deformations due to the pressure and weight of concrete poured into the formwork formed by these panels.

FR2712016 discloses a method of manufacturing formwork walls comprising an expanded metal plate provided with parallel ribs V-shaped. This mesh plate is attached to a plurality of stiffeners spaced at regular intervals and arranged perpendicularly to the ribs of the plate. The method comprises a stapling operation of the stiffeners on the plate, a first step consists in cutting legs by punching on one side of the stiffeners. In a second step, these tabs are folded over the ribs of the plate after passing through the mesh on each side of the ribs.

FR2497857 discloses a prefabricated panel comprising a frame formed of profiled stiffeners covered by a perforated metal sheet and at least one layer of coating material such as concrete. The stiffeners comprise tabs, issuing from one of the faces of the profile, passing through the perforated sheet to be folded on the outer face thereof so as to hook said sheet to the stiffeners.

Brief description of the invention

The object of the present invention is to reduce production costs and to rationalize the mass production of factory-made formwork panels while guaranteeing maximum strength for walls constructed with this type of formwork.

This object is achieved by a panel for formwork of walls or concrete slabs comprising a mesh metal sheet reinforced on the one hand by a plurality of stiffeners formed of profiled rigid metal bars integral with one face of said sheet arranged parallel to each other relative to one another. the others and spaced at predefined intervals, and secondly by ribs embedded in the mesh of the sheet spaced at predetermined intervals and crossing the stiffeners, the mesh sheet being fixed on the stiffeners, by means of a crimping performed at the level of At least one intersection between the ribs and the stiffeners, said panel is characterized in that the crimping is performed so that at least one metal portion of the rib maintains the stiffener through a corresponding orifice of said stiffener.

In practice, during the construction of a wall, the formwork is placed on a substantially horizontal surface (floor or floor slab) so that the stiffeners of the panels are arranged in the vertical direction. The ribs of the grid sheet perpendicularly cross the stiffeners and are therefore arranged horizontally and preferably at regular intervals over the entire height of the panel. The notions of vertical and horizontal are relative because the whole of the shuttering can be rotated at an angle of 90 °. Thus the vertical elements at the beginning become horizontal and vice versa.

A panel can be used as a single wall and placed either vertically against a wall to form a simple formwork, or horizontally for the realization of slabs.

The ribs are elongated profiled portions made of solid metal integrated in the mesh of the sheet used to stiffen it like stiffeners.

The grid sheet is attached at each intersection of a rib with a stiffener to minimize deformations caused by the weight of concrete poured into the formwork using these panels. This fixing is performed by crimping in which at least one tongue of the metal of the rib is cut by stamping and bent in a corresponding hole of the stiffener.

Brief description of the figures

The invention will be better understood from the detailed description which follows and which refers to the appended drawings which are given by way of non-limiting example, namely:

- Figure 1 illustrates a schematic overview of a formwork panel comprising a grid sheet provided with ribs fixed on the stiffeners by means of crimping.

- Figure 2 shows an enlarged view of the intersection between a rib of the grid sheet and a stiffener of the panel of Figure 1 with crimping the grid sheet on the stiffener.

- Figure 3 shows a cross section of the intersection of Figure 2 showing the crimping where tabs stamped into the rib hold the mesh sheet on the stiffener.

FIG. 4 represents a section diagrammatically along a horizontal axis of the panel of FIG. 1 showing the U-shaped section of the stiffeners - Figure 5 shows a section diagrammatically along a vertical axis of the panel of Figure 1 showing the profile of the U-shaped ribs.

- Figure 6 schematically illustrates the step of stamping an orifice at the intersection of a rib and a stiffener by pushing tabs on either side of the orifice.

- Figure 7 schematically illustrates the step of folding the tabs stamped against the inner face of a stiffener.

- Figure 8 schematically illustrates the result obtained after curvature of the tongues with a first variant of the crimping tool.

- Figure 9 schematically illustrates the result obtained after folding and flattening of the tongues with a second variant of the folding tool.

- Figure 10 schematically illustrates a variant of crimping in which the orifice has tabs on one side. They are held alternately on each side of the orifices stamped along a rib.

detailed description

The formwork panel (1) of FIG. 1 comprises a wire mesh sheet (2) extending over a plurality of stiffeners (3) arranged parallel to one another at regular intervals preferably. The grid sheet (2) has a plurality of parallel ribs (4) crossing the stiffeners (3), perpendicular preferably, and also arranged at regular intervals on the surface of the sheet (2). The grid sheet (2) is preferably crimped at each intersection between the ribs (4) and the stiffeners (3) in order to minimize the deformations due to the pressure of the concrete and ensure perfect attachment.

The stiffeners (3) consist of profiled steel bars generally U-shaped as shown in the horizontal section of the panel in Figure 7. The mesh sheet (2) is applied against the lower sides of the U-shaped sections and maintained by the ribs (4) at each crossing with these profiles. According to a preferred embodiment, the ribs (4) are U-shaped with the flat bottom portion placed on the stiffeners (3) as schematically illustrated by the vertical section of the panel in Figure 5.

The screen (2) is made by a known method, by stretching or deployment of a punched steel sheet with a plurality of blades. The ribs (4) are formed by stamping at predefined intervals of the sheet prior to deployment. They thus constitute integral parts of the screen sheet (2) without being reported on the screen as additional parts.

Figure 2 shows an enlarged view of an example of crimping at the intersection of a rib (4) and a stiffener (3). The stiffener (3) is pierced with a hole (5) for receiving tabs (6) stamped in the rib (4). The latter are bent, for example, on two opposite edges of the orifice (5) of the stiffener (3) towards the inside of the U-shaped section so as to bear against the inner face of the U of the stiffener (3). In the example, the rib (4) is stamped to create tongues (6) of sufficient length for their folding in the orifice (5) formed in the stiffener (3). In a practical embodiment the width of the U ribs (4) is 1.5 to 2 cm with a width of the U stiffeners of about 5 cm.

It should be noted that the profile of the ribs may have a different shape without flat portion applied against the stiffener, such as V-shaped where the edge is placed on the stiffener. In this case, the crimping tool locally deforms the rib so as to flatten it in the vicinity of the tongues. This deformation is considered acceptable both in terms of the strength of the crimping and the surface of the panel where the concrete coating compensates for irregularities.

An advantage of such crimping is that it can be done quickly with a suitable machine tool allowing at first to stamp the rib (4) and the stiffener (3) and in a second time fold the tabs respectively

(6) the rib (4) and the tongues (6 ') of the stiffener (3) in the orifice (5) of the stiffener (3). In order to maintain a precise alignment of the tongues (6) with the corresponding holes (5), stamping and bending operations of the tongues (6, 6 ') are performed simultaneously when the ribs (4) and the stiffeners (3) are kept in their final position on the machine. Figure 3 shows a section, along the axis AA, crimping a rib (4) U on a stiffener (3). During crimping, the tongues (6, 6 ') are formed both in the metal of the rib (4) and in that of the stiffener (4) and then curved one on the other at the edge of opposite sides of the metal. orifice (5) created during the stamping of the rib (4) and the stiffener (3).

According to one variant, the orifices (5) of the stiffeners (3) can be stamped during a preliminary stage. In this case, only the tabs (6) from the ribs are folded towards the inner face of the profile of the stiffener (3) during crimping.

Another advantage of this crimping is that it can be achieved with automated tools, regardless of external conditions and without altering the surface treatment of steel which is generally galvanized. In addition, any fixing defects are visible immediately and can be corrected before the exit of the formwork of the factory. These advantages do not occur when the mesh sheet is welded to the stiffeners requiring more expensive tools with higher energy consumption. In addition, in the case of welding, the surface treatment of the steel is degraded resulting in oxidation of the fixing points of the screen sheet adversely affecting the life of the wall built with the integrated formwork. This operation is only feasible in a dust-free environment, which implies expensive manufacturing conditions to implement and respect.

Fastening with screws or other fastening means adds additional parts to the panel, which is undesirable when the manufacturing needs to be maximally rationalized especially for large series.

The shape of the rib profile (4) and the dimensions thereof may vary depending on the strength requirements of the shuttering panel (1).

Tests have shown that the mode of crimping according to the invention offers better resistance when it is subjected to a pressure exerted by the concrete. Indeed, when the panels are used as formwork walls of a formwork for the construction of a wall, concrete poured into the space between the two walls exerts pressure against the inner faces of the walls. Crimping having tabs (6) bent inwardly of the formwork will have a gap resistance higher because the pressure of the concrete is exerted so as to apply the tabs (6) against the stiffeners by preventing them from leaving their orifices.

On the contrary, when the tongues of the crimping are folded over the outer face of the walls as in the crimping described in the document FR2712016, a spacing of the formwork walls under the pressure of the concrete can cause a recovery of the tongues. The latter can therefore be released mesh of the mesh causing the stall of the formwork wall and undesirable bulges on the faces of the wall. The attachment of the formwork wall stiffeners as presented in the document FR2497857 also has the same drawback.

The present invention also relates to a formwork comprising two panels (1), as described above, placed facing each other and connected by connecting elements articulated to the panels by means of the stiffeners (3). . These connecting elements to maintain the panels (1), either at a gap defining a gap for receiving concrete or similar material, or folded for storage and transport.

The wall erected with integrated formwork as described above is also an object of the present invention. The gap between the two panels (1) is filled with concrete or similar material.

A concrete slab made with a panel (1) described above is also an object of the present invention. The slab is made by placing the panel (1) generally horizontally with the face having the stiffeners (3) directed upwards. Reinforcing reinforcements are generally placed on the stiffeners before pouring a layer of concrete preferably uniform on this face. The quantity of reinforcement and the thickness of the concrete layer are determined according to the slab range, the loads, the concrete quality, etc.

The invention also relates to a method for producing a panel (1) for formwork of concrete walls or slabs comprising a wire mesh sheet (2) reinforced by ribs (4) with a profile comprising a flat part, said ribs (4) being integrated with the wire mesh of the sheet (2) and spaced at predefined intervals, and a plurality of u-shaped profiled rigid metal bars, called stiffeners (3), comprising the following steps:

arranging, on a suitable support, the stiffeners (3) parallel to one another, leaving predefined intervals between them, the lower side of the U of each stiffener (3) being directed upwards,

- Apply on the stiffeners (3) the wire mesh sheet (2) so that the ribs (4) perpendicularly cross the stiffeners (3) and that the flat portions of the profile of said ribs (4) bear against the lower side the U of each stiffener (3) at each intersection between the ribs (4) and the stiffeners (3),

- stamping an orifice (5) at least at an intersection between the stiffeners (3) and the ribs (4) by driving a suitable tool (10) so as to push back a portion of the metal of the rib (4) and the stiffener ( 3) towards the inside of the U-profile of the stiffener (3), fold down the metal portions, pushed previously, against the inner face of the stiffener profile (3) in order to crimp the wire mesh sheet (2) on the stiffeners (3).

FIG. 6 shows a schematic form of a stamping tool (10) for making an orifice (5) both through the rib (4) and the stiffener (3) while retaining metal portions attached to two sides of the orifice (5). In a practical embodiment, in a first step, the orifice (5) is stamped in the form of a rectangle so as to create tabs (6, 6 ') attached to the two opposite small sides. In a second step, the tongues (6, 6 ') directed towards the inner face of the profile of the stiffener (3) are folded against this face in an area adjacent to the short sides of the rectangle.

Figure 7 illustrates the intervention of a crimping tool (11) from the underside of the panel (1) after removal of the stamping tool (10). A support portion (10 ') of the stamping tool (10) remains resting on the rib (4) on an area around the orifice (5) in order to maintain the rib assembly (4) stiffener (3) when the folding tool (11) folds the tabs (6, 6 '). This tool (11) has an end of a shape dimensioned and adapted so as to curl the tongues (6, 6 ') against the inner face of the stiffener (3) as illustrated in FIG. 8.

According to one variant, the end of this tool (11) can deviate as it moves forward in order to completely flatten the tongues (6, 6 ') against the stiffener (3) in order to obtain a crimping as illustrated by FIG. figure 9.

According to a variant of the crimping illustrated in FIG. 10, the tongues (6, 6 ') are attached to a single small side of the rectangle of the orifice (5). In order to prevent the mesh sheet (2) from being stalled by an offset movement of the stiffeners (3), the stamping of the tongues is carried out so that they are retained alternately on the right and left sides of the orifices (5). aligned along the same rib (4). In addition, the tabs can also be alternately attached to the right and left sides of each hole (5) along each stiffener (3). They thus have a staggered configuration on all the intersections between the ribs (4) and the stiffeners (3) of the panel (1)

The manufacture of a panel is performed by a machine on which the grid sheet (2) is held temporarily flat on stiffeners by means of clamping devices.

The stamping and folding steps of the tongues (6, 6 ') are generally performed simultaneously on a plurality of intersections between at least one rib (4) and stiffeners (4) by a plurality of stamping tools. (10) and folding (11). These tools, aligned on at least one support parallel to the ribs (4) and arranged opposite said intersections advance along the interval between the ribs to crimp the mesh sheet (2) at each crossing of the ribs with the stiffeners.

Claims

1. Panel (1) for formwork of concrete walls or slabs comprising a mesh metal sheet (2) reinforced on the one hand by a plurality of stiffeners (3) formed of shaped rigid metal bars integral with one face of said sheet disposed parallel to each other and spaced at predetermined intervals, and secondly by profiled ribs (4) integrated into the mesh of the sheet (2) spaced at predetermined intervals and crossing the stiffeners (3), the mesh sheet ( 2) being fixed on the stiffeners (3), by means of a crimping performed at at least one intersection between the ribs (4) and the stiffeners, said panel (1) is characterized in that the crimping is carried out so that at least one metal portion of the rib (4) maintains the stiffener (3) through a corresponding orifice (5) of said stiffener (3).

2. Panel according to claim 1, characterized in that the stiffeners (3) consist of profiled U-shaped bars whose lower sides are applied against one side of the grid sheet (2), said stiffeners (3) being arranged at regular intervals on the grid sheet (2) and perpendicular to the ribs (4) of said sheet.

3. Panel according to claims 1 and 2, characterized in that the profile of the ribs comprises a flat portion applied against the stiffeners (3).

4. Panel according to claims 1 to 3, characterized in that at least one intersection with a stiffener (3) the ribs (4) are crimped so that a tongue (6), resulting from said rib (4) , through the corresponding orifice (5) of the stiffener (4) and is folded against the inner face of the stiffener (3) at the edge of said orifice (5) so as to bear against the inner face of the stiffener (3).

5. Panel according to claims 1 to 4, characterized in that the tabs are alternately attached to the right and left sides of the orifices (5) aligned along the same rib (4).

6. Panel according to claims 1 to 5, characterized in that the tongues are alternately attached to the right and left sides of each orifice (5) along each stiffener (3).

7. Panel according to claims 1 to 3, characterized in that at least one intersection with a stiffener (3), the ribs (4) are crimped so that two tongues (6) opposite one with respect to the other, issuing from said rib (4), pass through the corresponding orifice (5) of the stiffener (4) and are each folded against the inner face of the stiffener (3) at the edge of opposite sides of said orifice (5) so as to lean against the inside of the stiffener (3).

8. Formwork characterized in that it comprises two panels (1), according to any one of claims 1 to 7, placed opposite each other and connected by articulated connecting elements audits panels (1) by the stiffeners (3), these connecting elements to maintain the panels (1), either at a gap defining a gap for receiving concrete or similar material, or folded for storage and transport.

9. Wall characterized in that it comprises an integrated formwork according to claim 8, the gap separating the two panels (1) being filled with concrete or similar material.

10. Slab characterized in that it comprises an integrated panel (1), according to any one of claims 1 to 7, placed generally horizontally with the face comprising the stiffeners (3) directed upwards, reinforcing reinforcements and a layer of concrete or similar material is deposited on said face.

11. Method of producing a panel (1) for formwork of concrete walls or slabs comprising a mesh metal sheet (2) reinforced by ribs (4) with a profile comprising a flat part, said ribs (4) being integrated in the mesh of the sheet (2) and spaced at predefined intervals, and a plurality of U-shaped profiled rigid metal bars, called stiffeners (3), comprising the following steps:

- Apply on the stiffeners (3) the wire mesh sheet (2) so that the ribs (4) perpendicularly cross the stiffeners (3) and that the parts planes of the profile of said ribs (4) rest against the lower side of the U of each stiffener (3) at each intersection between the ribs (4) and the stiffeners

(3),

- stamping an orifice (5) at least at an intersection between the stiffeners (3) and the ribs (4) by driving a suitable tool (10) so as to push back a portion of the metal of the rib (4) and the stiffener ( 3) towards the inside of the U-profile of the stiffener (3),

- Fold down the metal portions, previously pushed, against the inner face of the stiffener profile (3) for crimping the wire mesh sheet (2) on the stiffeners (3).

12. Method according to claim 11, characterized in that the orifice (5) is stamped in a generally rectangular shape so as to create tabs (6, 6 ') held on at least one small side of the rectangle both in the metal of the rib (4) and in that of the stiffener (3).

13. Method according to claims 11 and 12, characterized in that the tongues (6, 6 ') are folded against the inner face of the stiffener (3) in an adjacent area of the orifice (5) stamped with a crimping tool (11) operating from the inner face of the stiffener (3), a support portion (10 ') of the stamping tool (10) resting on the rib (4) in the vicinity of the orifice (5).

14. The method of claim 11 characterized in that the steps of stamping and crimping of the stamped metal portions are performed simultaneously on a plurality of intersections between at least one rib (4) and stiffeners (4) by a plurality of tools (10, 11) aligned on at least one support parallel to the ribs (4) and arranged opposite said intersections, said tools advance according to the intervals separating the ribs on the mesh sheet (2) and perform crimping at least an intersection.

15. Machine for producing a panel (1) for formwork walls or concrete slabs implementing the method according to claims 11 to 14.