FR2665721A1 - Shuttering based on stabilised timber elements, for the erection of pillars made of concrete - Google Patents

Abstract

Shuttering based on stabilised timber elements, for the erection of pillars or columns made of concrete, formed by two half-shells or shuttering halves comprising in each case an inner shuttering wall (2) designed as a function of the cross-section of the pillars or columns to be obtained, and an external stiffening framework consisting of a plurality of templates or half-templates (3) which are spaced apart, fixed on the said shuttering wall (2) and are distributed along the height of the latter, and two stiffening beams or uprights (12) joining the said half-templates (3) and fixed on the outer side of the latter, the two half-shells thus formed being assembled with the aid of clamping means (17a, 17b, 17c), characterised in that the templates or half-templates (3) are formed by a shaped plywood element having an inner cutout (4) closely matching the outer surface of the shuttering wall (2) against which they are fixed, and external cutouts or notches (11) in which the said stiffening beams (12) are engaged and fixed.

Description

Formwork based on stabilized elements in boSs, for erecting concrete posts.

 The present invention relates to a formwork based on humpback stabilized elements for the manufacture of concrete or reinforced concrete posts or pillars.

 We know (FR-A-2,474,569) formwork in boSs for the manufacture of concrete or reinforced concrete posts or columns, composed of two half-shells or formwork halves each comprising: - an internal vertical or paroli coating shuttering generally constituted by a plywood of suitable thickness and whose internal surface constitutes the shuttering face; - And an external stiffening frame executed in massive boSs and made up of a plurality of squares or dies of spaced angles, distributed along the height of the shuttering panel and two vertical beams joining the superimposed branches of said brackets and fixed on the outer side of said branches, near the free ends thereof; the half-shells or formwork halves thus produced being assembled by means of tie rods making it possible to press one against the other the adjacent vertical edges of their formwork walls, in order to ensure their tight junction.

 Such lightweight formwork and economical manufacturing, provide the advantage of great ease of installation and removal. It is enough, in fact, to put them in place, to arrange them around the frame of future posts, using a crane or other construction machine, then to join their two halves, by tightening the nuts on the threaded rods of the tie rods; removal is just as easy, by simply loosening the tie rods and removing the formwork from above, using the crane.

 To maintain the correct alignment and the tight junction of the vertical edges of the formwork walls of these forms, it is however essential to provide a relatively small distance between the superimposed belt brackets, the number and, consequently, the number tightening tie rods are a function of this requirement.

 On the other hand, the angle brackets or dies are executed using two solid wooden crosspieces assembled orthogonally by means of plywood gussets Although it is possible to give their internal support surface, at the time of their manufacture, a very precise configuration, as a function of that of the shuttering wall, the durability of this configuration is not guaranteed, so that their deformation, even slight, can have a harmful influence on the junction and the alignment vertical edges of the two halves of the shuttering wall and, therefore, on the sealing of this junction.We have made provision, to overcome this drawback, to place the ends of the brackets in contact and to equip these ends with complementary means centering formed by bosses and sockets reinforced with steel parts, which complicates the manufacture of said brackets and gives a more or less efficient result.

 In addition, the clamping rods must pass through holes made in the solid wood beams constituting the vertical beams, which constitutes a cause of weakening of the resistance of the latter to bending forces, which is remedied by using two beams. twinned between which said rods pass, which however increases the cost price and the weight of the formwork.

 The object of the invention is in particular to improve the performance of wooden formwork of the aforementioned kind.

 According to the invention, this objective is achieved thanks to a formwork composed of two half-shells or formwork halves each comprising an internal formwork wall shaped according to the section of the posts or columns to be produced, and an external stiffening frame consisting of a plurality of spaced-apart templates or half-hoops, fixed on said formwork wall and distributed along the height of the latter and two straightening beams or uprights joining said half-hoops and fixed on the outside of the latter , the two half-shells thus produced being assembled using clamping means, this formwork being in particular remarkable in that each jig or half-hoop is constituted by a single piece of swivel plywood having an internal cut closely following the surface external of the formwork wall against which it is fixed and external cutouts in which are engaged and f ixed the shooting beams; each half-hoop being thus constituted by a monobloc structure, as opposed to traditional structures composed of several pieces of solid wood and / or plywood.

 According to another characteristic arrangement of the invention, the junction ends of the half-hoops are provided with centering means of the type with conical or semi-conical engagement, these centering means being obtained by cutting the half-hoops.

 According to another characteristic arrangement of the invention, the beams for distributing force are advantageously constituted by beams with a lamellar structure of the kind described in document WO 86/06315.

 According to another characteristic arrangement of the invention, each drawing stiffening beam comprises a surface for receiving a clamping force disposed in a plane oriented in the same direction as that of a surface for receiving a clamping force which the dem; -ces on which it is fixed, and the clamping means comprise force distribution plates making it possible to exert pressure on these two surfaces as; can between oriented parallel or coplanar, these plates being provided with a hole for the passage of the rod of the clamping means.

 The formwork according to the invention offers the advantage of being entirely produced by means of stabilized wooden elements; it is light and practically non-deformable, both under the pressures resulting from the pouring of concrete, and under variations due to atmospheric conditions.

 In this way, it is not necessary to place clamping means at each hoop or belt element; material savings are thus achieved at the same time as the time usually required for setting up and removing comparable formwork is reduced. Savings are also achieved by reducing the number of vertical stiffening beams used individually without drilling for the passage of the rods of the tie rods, while these beams are usually drilled and twinned.

 The invention also makes it possible to obtain better alignment and a better ensured junction of the vertical surfaces in contact with the shuttering wall halves and, consequently, to obtain better sealing at this junction.

The aims, characteristics and advantages above, and others still, will emerge more clearly from the description which follows and from the appended drawings in which:
Figure 1 is an elevational view of a column formwork, executed according to the invention.

Figure 2 is a plan view of this formwork
Figure 3 is an enlarged view in cross section along line 3-3 of Figure 1 showing a formwork for the manufacture of posts or columns of circular section.

 Figure 4 is a view similar to Figure 3 and showing a formwork for the execution of posts or pillars of square section.

 FIG. 5 is a detail view on a larger scale of FIG. 3.

 FIG. 6 is a detail view on a larger scale of FIG. 4.

 FIG. 7 is a partial side view of a formwork produced according to the embodiment illustrated in FIGS. 3 and 5.

Reference is made to said drawings to describe examples of interesting execution, bSen that in no way limitative, of the formwork according to; nventionz
This formwork consists of two half-shells or formwork halves 1, the length of which is a function of the maximum height of the posts or columns that it is desired to be able to erect using said formwork.

 Each of the dem-shells 1 includes a vertical coating or shuttering wall 2 qu; may be formed by a solid preformed plywood or by boards of boards assembled longitudinally, and the internal face or formwork face is treated in the usual manner.

 Depending on the destination of the mold, the shuttering panel may be constituted by a dem; -cylinder, by two adjacent sides of a parallelepiped of square or other section, etc., so as to allow a mold of circular, square or other, after assembling the two formwork halves.

 On the external face of the formwork wall 2 and perpendicular to the axis of the latter, are fixed, for example by nailing, screwing or gluing, of the half-holes 3 distributed, preferably at regular intervals (for example every 30 cm), over the entire height of said shuttering panel.

 According to the invention, each of these dem; -ces 3 (also called brackets, or jigs, or pairs) is constituted by a single piece of a solid plywood fretwork having an interior cutout 4 whose shape or configuration closely matches the shape or configuration of the external surface of the half of shuttering form 2 or dem; -couchis 2 against which said half-hoops are fixed. Dem; -cerces 3 are, for example, fretted with a router bit with numerical control controlled by computer what; allows to obtain, in an economical way, high precision parts.

 After assembly of the dem; -shells, the dem; -ces constitute complete hoops or superimposed belt elements.

 The joining surfaces of the dem; -ces are cut by framing so as to allow their self-centering during the assembly of the formwork halves.

More specifically, these surfaces are contoured to allow their junction by conical or semi-conical engagement, one of the junction surfaces of each half-hoop 3 having a tongue with a curved edge 5 while its other junction surface has a notch curved profile 6 so as to cooperate with an identical notch and tongue, respectively, of the homologous half-hoop 3.

 Each surface or junction end of the half-hoops 3 can also advantageously include, in its internal edge, a notch 7 of substantially rectangular section, in which is embedded a cleat extending over the entire length or height of the formwork wall. The surface 8a of this cleat which is placed in contact with the external surface 2a of the shuttering wall 2 has a conformation allowing it to closely match the latter. The junction surface of the cleats 8 has a longitudinal groove 9 in which is housed a seal 10. These cleats are made of stabilized wood such as laminated wood veneer. They ensure the continuity of the junction and the tightening of the shuttering wall 2, between the hoops 3-3.

 The half-hoops 3 also include notches or lateral cutouts 11 cut by fretwork, in their outer edge, in the vicinity of their junction ends, these notches preferably having a rectangular shape and their long side 11a entering oriented perpendicular to the plane. junction has half-shells or formwork halves 1.

 In these notches or cutouts 11 are wedged and fixed, the vertical rails or shooting beams 12 assembled to the half-hoops by screwing or otherwise.

 These vertical beams can advantageously be constituted by beams with a lamellar structure and, preferably, by beams with a lamellar structure of the kind which are described in document WO 86/06315 and which are remarkable in that they are provided equidistant transverse holes 12b passing right through them, in the direction of their thickness and distributed over their entire length.

 Such elements with a lamellar structure are light, robust and non-deformable and they allow, in addition, the attachment of various equipment such as stabilizers S, concreting consoles s, etc. (Figures 1 and 2).

 These beams have a rectangular section and have faces or facings and longitudinal sides or sections of narrower width than that of said faces. Preferably, they are positioned so that they are applied, via one of their faces, against the long side 11a of the notch 11, while their edges and in particular their outer edge 12a is disposed parallel to the junction plane aa of the half-shells.

 Each half-hoop 3 has, near the notches 11, a force receiving surface 13 disposed in a plane pp oriented in the same direction as the plane p'-p 'in which the lateral force receiving surface is located. or external edge 12a of the shooting beam 12 wedged in said notches.

 According to the embodiment illustrated in FIGS. 3 and 5, the surfaces 12a and 13 are parallel, the surface 13 being withdrawn therefrom relative to the surface 12a, while according to the exemplary embodiment represented in FIGS. 4 and 6, these surfaces are coplanar.

 According to the embodiment illustrated in FIGS. 3 and 5, a wooden skid shoe is fixed, flat, by nailing or otherwise, against each surface 13 of the half-hoops 3, the external surface 14a of these skids being arranged in the same plane p'-p 'as that where the lateral force-receiving surface or external section 12a of the beams 12 is located. The beams 14 extend over the entire length or height of the formwork halves and a space e is reserved between each of them and the adjacent shooting beam 12 (FIG. 7).

 At each half-hoop 3, or at a certain number of them only distributed over the entire height of the two formwork halves, force distribution plates 15 are fixed, resting on the surfaces 12a and 14a (Figures 3 and 5) or on surfaces 12a and 13 (Figures 4 and 6).

 These force distribution plates can be cut out of a sturdy plywood and fixed, by nailing or otherwise, on the shooting beams 12 and on the shooting pads (Figures 3 and 5) or on the shooting beams 12 and on the half-hoops 3 (Figures 4 and 6). They have a dimension (height) significantly greater than the thickness of the half-hoops 3 and they are fixed so as to extend above and below the latter.

 The force distribution plates 15 have a hole 16 for the passage of the rod of the clamping means, the axis of this hole being placed above or below the upper or lower faces, respectively, of the half-hoop around 3 and, close to said faces.

According to the embodiment illustrated in FIGS. 3, 5 and 7, the axis of the hole 16 is arranged in the space "e" reserved between the shooting beams 12 and the shooting pads 14.

 The clamping means 17 are, for example, constituted by conventional tie rods or tensioners comprising a threaded rod 17a with rapid pitch on the ends of which are mounted a support plate 17b and a wing nut 17c axially movable.

 It can be seen that a single drawing stiffening beam 12 is housed in each external cutout 11 of the half-hoops 3 and that this shooting beam does not have any holes for the passage of the rod 17a of the tie rods 17, this rod 17a passing, in effect, outside of said shooting beam.

 Thanks to the invention, it is not necessary to place tie rods at the level of all the forms of the formwork, for the tightening of the latter, as shown in FIG. 1, while obtaining a good tightening of the two half-shells and good sealing of the junction edges thereof.

 According to the invention, the clamping forces resulting from the use of the clamping means 17 are exerted perpendicularly to the junction plane (aa) of the two half-shells 1, corresponding to the junction surfaces of the latter, these surfaces comprising : the vertical edges 2a of the shuttering walls 2, the external surface 8a of the brackets 8 and the end surface 3a of the half-hoops 3.

 On the other hand, the clamping forces resulting from the implementation of the clamping means 17 is exerted in the width direction of the stiffening beams 12, that is to say in the direction where they have the greatest resistance to crushing.

 At its upper part, the formwork is provided, in a manner known per se, with lifting brackets (not shown) enabling it to be suspended from a crane or other site handling machine.

Claims (8)

1. - Formwork based on stabilized wooden elements, for the erection of concrete posts or columns, composed of two half-shells (1) or halves of formwork each comprising an internal formwork wall (2) shaped as function of the section of the posts or columns to be obtained, and an external stiffening frame made up of a plurality of templates or dem ;; - spaced hoops (3), fixed on said formwork wall (2) and distributed along the height of the latter and two straightening beams or uprights (12) joining said half-hoops (3) and fixed on the outer side thereof, the two half-shells (1) thus arranged being assembled using clamping means (17), characterized in that the jigs or half-hoops (3) are formed by a plywood with an outline having an internal cutout (4) closely matching the external surface of the formwork wall (2) against which they are fixed and cutouts or enta outer islands (11) in which are engaged and fixed said stiffening beams (12). 2. - Formwork based on stabilized wooden elements according to claim 1, characterized in that the junction ends of the half-hoops (3) are provided with self-centering means (5, 6) of the engagement type conical or semi-conical, obtained by fretwork. 3. - Formwork based on stabilized wooden elements according to one of claims 1 and 2, characterized in that the drawing stiffening beams (12) consist of beams with lamellar structure, preferably provided with a plurality equidistant holes (12b) passing right through them, in the direction of their thickness and distributed over their entire length. 4. - Formwork based on stabilized elements in boSs, according to any one of claims 1 to 3, characterized in that a single drawing stiffening beam (12) is housed in each external notch (11) and in that that the rods (17a) of the clamping means (17) pass outside this single shooting beam (12) * 5. - Formwork based on stabilized wooden elements, according to any one of claims 1 to 4 , characterized in that each stiffening shooting beam (12) comprises a surface (12a) for receiving the clamping force disposed in a plane (p'-p ') oriented in the same direction as that (pp) of a surface (13) for receiving the clamping force presented by the half-hoops (3) on which it is fixed, and in that the clamping means comprise plates (15) for distributing force making it possible to exert a pressure on these two surfaces (12a, 13) and provided with a hole (16) for the passage of the rod (17au of said hubs tightening ns. 6. - Formwork based on stabilized wooden elements, according to claim 5, characterized in that the force-receiving surfaces (12a, 13) of the drawing stiffening beams (12) and of the half-hoops are coplanar, and in that the force distribution plates (15) are directly fixed on said surfaces (12a, 13). 7. - Formwork based on stabilized wooden elements, according to claim 5, characterized in that the force-receiving surfaces (12a, 13) of the drawing stiffening beams (12) and half-hoops (3) are arranged in parallel planes (pp, p'-p '), the force receiving surface (13) of the half-hoops (3) being set back relative to the force receiving surface (12a) stiffening shooting beams (12), and in that a wooden spinning shoe (14) is fixed against the force-receiving surfaces (13) of the half-hoops (3), these shoes having an external surface ( 14au arranged in the same plane (p'-p ') as that where the force-receiving surface (12a) of the stiffening shooting beams (12) is placed, the force distribution plates (15) being fixed on the coplanar surfaces of the sliding shoes (14) and the shooting beams (13) 8. - Formwork based on stabilized wooden elements according to any one of the resellers ications 5 to 7, characterized in that the force distribution plates (15) are fixed at the level of the half-hoops (3) or of some of them only distributed over the entire height of the half-shells (1) , the axis of the hole (16) for passage of the rods (17) of the clamping devices being placed above or below the upper or lower faces, respectively, of said neighboring half-hoops (3), and near said faces. 9. - Formwork based on stabilized wooden elements according to any one of claims 1 to 8, characterized in that threaded battens (8) extending over the entire height of the half-shells (1) are embedded and fixed in notches (7) formed in the internal edge of the surfaces or junction ends of the half-hoops (3), these cleats resting against the external surface of the vertical edges of the formwork walls (2). 10. - Formwork based on stabilized wooden elements according to claim 9, characterized in that the junction surface of the battens (8) is provided with a longitudinal groove (9) in which is housed a seal (10) .  11. - Formwork based on stabilized elements in boSs, according to any one of claims 1 to 10, characterized in that the clamping forces resulting from the use of the clamping means (17) are exerted perpendicularly at the junction plane of the two dem; -shells (1) or at the junction surfaces (2a, 8a, 3a) of these ;.