FR2923241A1 - Secondary support girder for casing concrete slab in building, has vertical support zone whose width is greater than width of upper bearing surface and laterally extending from both sides of bearing surface - Google Patents

Abstract

The girder (3a) has an elongated girder body (5) including an upper bearing surface (6) and two connecting structures (7, 10) fixed to respective beams. Each structure comprises a lower hooking structure (7a) vertically supported by simple downward displacement on a lateral receiving structure of one of the beams along a vertical support zone (70), and hooked to the receiving structure in a manner to oppose axial displacement and deviation of the beam. The vertical support zone has width greater than width of the bearing surface, and laterally extends from both sides of the bearing surface.

Description

The present invention relates to the field of building, and more particularly the support structures of a slab formwork or the like. In the manufacture of a concrete slab, a formwork must be made capable of supporting and containing a mass of pasty concrete for a sufficient period of time until it is set. It is therefore necessary to support the formwork by a robust support structure comprising struts and beams connected together to define a generally flat meshed frame.

In order to facilitate assembly, disassembly, handling and transport of the supporting structure, it has already been proposed modular support structures composed of the assembly of inserts, namely struts, primary beams and secondary beams. The props are capable of carrying the primary beams which themselves are capable of supporting two by two a plurality of secondary beams perpendicular to the primary beams. Such a modular support structure for slab formwork or the like is described, for example, in EP 1 234 929 A1. In this document, the secondary support beams are intended to be arranged between two parallel primary beams to form a flat modular framework. supported by props. Each secondary beam comprises an elongated beam body having an upper bearing surface and having at its ends two connecting structures adapted to be fixed to the respective primary beams. Each connection structure comprises a lower hooking structure shaped to come into vertical support by simple downward movement on a lateral structure for receiving the primary beam in a bearing zone, and to cling to this lateral receiving structure. so as to oppose any axial displacement towards and away from the primary beam. The secondary support beams, made of light metal alloy, thus constitute easily manipulable elements, the assembly is easily made by simply engaging up and down hooking structures in lateral receiving channels of the primary beams. The lower position of the hooking structures makes it possible to give them a sufficient thickness guaranteeing a good mechanical resistance to resume the support efforts of the slab formwork during and after the pouring of the concrete. Thus, such a structure meets the needs of maneuverability and robustness.

However, it appears that the secondary supporting beams thus formed exhibit a lack of stability when the workers walk on the

secondary beams of support before the completion of the formwork. In fact, the secondary support beams then undergo lateral forces likely to tilt around their longitudinal axis, thus rendering ineffective the lower hooking structure. In the event of a tilting, the secondary support beam can then become detached from the primary beams and fall, creating a

free space through which the body of the worker can also engage and fall.

It is not economically reasonable to have secondary support beams contiguously side-by-side to prevent them from tilting.

It has already been imagined to link several secondary beams of support

to each other to form a stable structure. This solution naturally avoids the tilting of the beams, but requires either to build sets of heavier beams and unwieldy, or to add connecting elements that must be put and remove during assembly and disassembly of the modular support structure , which complicates operations by making more

expensive and more dangerous the assembly and disassembly of the structure, and increasing the number of parts to assemble.

The problem proposed by the present invention is to design other means which, without additional parts, ensure both a high strength of the supporting secondary beam structure to support the

formwork support constraints, ensure good handling especially for the mounting and dismounting of the support structure, and effectively oppose the relative movements of successive secondary support beams likely to cause a fall of a user walking on the support structure.

To achieve these and other objects, the invention provides a secondary support beam for slab formwork or the like, intended to be disposed between two primary beams to form a modular support structure supported by struts, wherein:

the secondary supporting beam comprises an elongated beam body having a bearing upper face and having at its ends two connecting structures for attaching to the respective primary beams; each connecting structure comprises a lower structure of shaped hooking to come into vertical support simply by moving downward on a lateral structure for receiving the primary beam in a vertical support zone, and for hooking on the lateral receiving structure so as to oppose any axial displacement towards and away from the primary beam, - the vertical bearing zone has a width greater than the width of the upper side of the secondary beam and extends laterally on either side beyond of it. By maintaining the hooking structure in the lower position, it can be given a thickness sufficient to guarantee its robustness and resume the compression of the substantial support forces of a formwork, without the risk of breaking or deformation of the lower hooking structure. . Simultaneously, by laterally increasing its width, beyond the upper bearing surface of the secondary supporting beam, the stability of the secondary support beam is ensured by the fact that a more or less vertical force exerted by a user on the upper surface of secondary support beam generates, by the lower hooking structure, reaction forces which oppose the axial rotation of the secondary support beam. An improvement in stability can still be ensured by providing that the distance between the upper bearing surface and the lower hooking structure is less than or equal to the width of the vertical bearing zone. A good compromise between stability and mechanical bending strength of the secondary support beam is achieved by providing that the distance between the bearing upper face and the lower hooking structure is substantially equal to the width of the vertical support zone. In practice, the lower hooking structure may comprise two hooking members, laterally spaced apart from each other by a distance such that they occupy a width greater than the width of the bearing surface of the secondary beam, and adapted to engage in a side chute receiving the primary beam. The secondary support beam thus rests by four points of support on two main beams, achieving a stable support. Preferably, the connecting structure further comprises an upper axial bearing structure adapted to come bearing laterally against the primary beam. The axial support, exerted in the upper part of the connecting structure, also allows to oppose, by friction on the primary beam, the risks of rotation of the beam about its axis. This further promotes the stability of the secondary support beam. In practice, the upper axial bearing structure may comprise two bearing noses laterally spaced from each other, and coming directly above the hooking members 5 in the longitudinal direction of the secondary supporting beam. A recess can thus be made between the two axial support nose to lighten the secondary support beam. According to an advantageous embodiment, the beam body comprises a central cross-section with a generally I-shaped cross-section, with a vertical central branch, two lower lateral stiffening wings and a flared upper stiffening structure forming the load-bearing upper face of the beam. the secondary support beam, and comprises two attachments, each endpiece having a transverse plate supported in a first face against the end of the central section and provided with stabilizing gussets which are fixed to the lower lateral stiffening wings of the central section. on either side of the vertical central branch, the second transverse support plate face having the elements of the connecting structure. This facilitates the realization of secondary support beam body.

The end inserts must be fixed sufficiently rigidly and reliably to the ends of the central section, in particular avoiding any risk of deformation during impacts that the beam is likely to undergo during handling and transport. In particular, the fixing with stabilizing gussets avoids the risk of pivoting of the transverse plate around the edge formed by the vertical central branch of the central section. In order to further lighten the beam, it is advantageous to provide that the transverse end plate has: - in front view, a width which decreases regularly from the lower hooking structure to the upper axial bearing structure In a side view, a thickness which decreases steadily from the lower hooking structure to the junction with the protruding axial upper bearing structure. This ensures simultaneously a sufficient strength of the connecting structure of beams, and a significant lightening reported tips 35 constituting the connecting structure. According to a preferred embodiment, the central section is made of extruded aluminum alloy, while the end pieces are made of molded aluminum alloy 5208FDEP.ace 2923241 5. The cast alloy has a lower hardness, which promotes friction between each connecting structure and the primary beams. This further reduces the risk of displacement of the lateral support beam by lateral sliding with respect to a primary beam, sliding 5 likely to increase the spacing between two successive secondary support beams, spacing which would then be likely to leave the passage a member of the user. According to another aspect, the invention proposes a modular support structure for slab formwork or the like, comprising primary beams 10 supporting two by two secondary support beams as defined above, the secondary support beams being spaced apart. one of the other with a pitch such that the interval between the upper bearing surfaces of two successive secondary supporting beams is less than about 14 cm. This ensures, thanks to the natural stability of secondary support beams 15, a lightening of the modular support structure while ensuring the safety of use, the workers can walk on the modular support structure without the risk of tipping the beams. secondary support. Other objects, features and advantages of the present invention will become apparent from the following description of particular embodiments, with reference to the accompanying figures, in which: FIG. 1 is a general perspective view of a modular structure formwork support according to an embodiment of the present invention; FIG. 2 is a perspective view of a secondary support beam according to an embodiment of the present invention; FIG. 3 is a side view of the secondary support beam of FIG. 2; FIG. 4 is an end view of the secondary support beam of FIG. 2; FIG. 5 is a perspective view in FIG. transverse section of the secondary support beam of FIG. 2; - Figure 6 is a cross-sectional view of the secondary support beam of Figure 2; - Figure 7 is a cross sectional view of the central section forming the secondary support beam body of Figure 2; Figure 8 is a cross-section of a primary beam on which the secondary support beam of Figure 2 can be fitted; and FIG. 9 is a side view illustrating the assembly of one end of the secondary support beam of FIG. 2 on the primary beam of FIG. 8. As illustrated in FIG. modular support structure of a slab formwork or the like comprises a substantially planar meshwork 1 composed of a set of primary beams such as the beams 2a, 2b, 2c and 2d, some of which (the beams 2a, 2c and 2d ) are butted, and which support in pairs (beams 2a and 2b) supporting secondary beams such as beams 3a and 3b arranged perpendicularly to the primary beams 2a and 2b.

The mesh structure 1 is held horizontally and is carried by vertical struts 4. FIGS. 2 and 3 show, in perspective and in side view, a secondary support beam structure such as the beam 3a of the Figure 1, according to one embodiment of the invention.

This secondary support beam 3a comprises an elongated beam body 5 having a bearing upper face 6 and having at its ends two connecting structures 7 and 10 for attaching to the respective primary beams 2a and 2b (FIG. 1). The two connecting structures 7 and 10 are identical. Thus, only the connecting structure 7 will be described. The connecting structure 7 has a lower hooking structure 7a and an upper axial bearing structure 7b. The lower hooking structure 7a comprises two hooking members 7c and 7d, laterally spaced from each other by a distance D (FIG. 4) such that the hooking members 7c and 7d occupy a width LI which is more large than the width LH of the upper bearing surface 6 of the secondary support beam 3a. The hooking members 7c and 7d define a vertical support zone 70 (FIGS. 4 and 6) which extends along said width LI. As can be seen in these FIGS. 4 and 6, the vertical support zone 70 has a width L1 greater than the width LH of the bearing upper face 6, and it extends laterally on either side of the bearing upper face 6 beyond it. The upper axial bearing structure 7b comprises two bearing noses 7e and 7f, spaced laterally from one another, and which occupy a width substantially equal to the width LH of the upper bearing surface 6.

In the illustrated embodiment, the two support noses 7e and 7f come in line with the hooking members 7c and 7d in the longitudinal direction of the secondary supporting beam 3a.

FIG. 5 is a perspective view seen from the rear of a section of the secondary support beam 3a with the connecting structure 7. In this embodiment, the beam body 5 comprises a central section 8 with cross-section generally shaped in 1, with a vertical central branch 8a, two lower lateral stiffening wings 8b and 8c, and a flared upper structure 8d of stiffening forming the upper bearing surface 6 of the beam secondary support 3a. The upper flared structure 8d comprises a lower box 8e with 10 generally triangular section which widens since its connection to the central branch 8a and is connected to two parallel upper lateral wings 8f and 8g defining an upper groove 8h (FIG. 7), open upwards, and intended to receive and hold a wood insert 8i (Figures 5 and 6) to form, with the upper edge of the two upper lateral wings 8f and 8g, the upper bearing surface 15 of beam. The upper edges of the upper lateral wings 8f and 8g comprise two lateral sidewalks 8j and 8k horizontal whose ends delimit the upper bearing surface 6 of beam. Thus, the outer edges of the lateral sidewalks 8j and 8k are spaced apart by the distance LH and define the width LH of the load-bearing upper face 6 of the beam. The upper lateral wings 8f and 8g also have on their external faces, horizontal stiffening ribs such as the rib 8m (Figures 6 and 7). Sidewalks 8j and 8k have longitudinal striations to form a non-slip surface.

The wood insert 8i may be secured by self-tapping screws, or by any other means such as gluing. It is used for the subsequent fixing of the shuttering plates on the secondary supporting beams 3a. In the preferred embodiment which has been illustrated in the figures, the beam body 5 comprises the central cross-section section 8 with a generally 1-shaped cross-section and two pointed end-pieces 9 and 11 respectively constituting the two connecting structures 7 and 10. Thus, the tip 9 is attached to a first end of the central section 8, and the tip 11 is attached to the other end of the central section 8. The tips 9 and 11 are identical, and we will therefore describe only the tip 9, in connection with Figures 4 to 6. The tip 9 comprises a transverse plate 9a, having a first face resting against the end of the central section 8 and provided with two gussets of 5208FDEP.doc 2923241 8 stabilization 9b and 9c that can be attached to the lower lateral stiffening wings 8b and 8c respectively of the central section 8 on either side of the vertical central branch 8a. A second opposite face of the transverse support plate 9a 5 comprises the elements of the connecting structure 7 previously described. The central section 8 is advantageously made of extruded aluminum alloy, giving it a relatively high hardness and rigidity, and easily achievable at a lower cost. On the other hand, the ends 9 and 11, of more complex shape, are advantageously made by molding an aluminum alloy. They thus have a lower hardness, which promotes a better coefficient of friction with the primary beams 2a and 2b on which they come to engage. In a front view, illustrated in FIG. 4, the transverse plate 9a of the tip 9 has a width which decreases regularly from the lower hooking structure 7a to the upper axial bearing structure 7b, as represented by FIG. Figure, the contour of each side edge generally being S. Thus, the width of the lower portion of the transverse plate 9a of the nozzle 9 is equal to the width LI defined by the hooking members 7c and 7d. The width of the upper part of the transverse plate 9a of the end piece 9 is equal to the width LH of the upper bearing face 6 of the secondary supporting beam 3a. In side view, illustrated in FIG. 9, the transverse plate 9a of the tip 9 has a thickness E which decreases steadily from the lower hooking structure 7a to the junction with the prominent axial bearing structure 7b. . This defines a generally triangular front recess 9d which widens upwards until it reaches the upper axial bearing structure 7b, while the thickness E of the transverse plate 9a is reduced upwards while retaining a large thickness in the lower part of plate, part occupied by the lower hooking structure 7a. As a result, the lower hooking structure 7a, of greater thickness, is robust to resume the compression of the mechanical support forces of a formwork. In front view, that is to say in Figure 4, the hooking members 7c and 7d are separated by a recess 9e, which promotes the lightening of the workpiece. The end pieces 9 and 11 are advantageously fixed by welding to the central section 8. In use, the secondary support beam 3a engages, by its connecting structure 7, on a primary beam 2a as illustrated on the 5208PDEP.doc For this, the primary beam 2a may for example be as described in EP 1 234 929 A1, and as shown in cross section in Figure 8. The primary beam 2a is a profile forming a body 12a with lower box 12b and upper box 12c, with 12d and 12th lateral chutes at the central height, and with lateral fins 12f and 12g at the upper end. The lateral chutes such as the trough 12d are open upwards over the entire length of the primary beam. The lateral chute 12d is delimited by a flat bottom 12h, an inner face 12i constituted by the wall of the upper box 12c, and an outer face constituted by an oblique rib 12k. In this way, the lateral chute 12d is flared upwards. Referring again to Figure 9, we see that the hooking member 7c is a thick tongue pointing downwards, shaped to engage low clearance in the lateral chute 12d.

Thus, the hooking member 7c is separated from the transverse plate body 9a by a transverse lower groove 9n into which the oblique rib 12k of the primary beam 2a engages. Simultaneously, while the hooking member 7c is engaged in the lateral chute 12d, the bearing nose 7e of the upper support structure 7b bears against the lateral face of the primary beam 2a. In practice, with a primary beam as illustrated in Figure 8, the support nose 7e abuts on the outer edge of the lateral fin 12f of the primary beam 2a. In practice, the secondary supporting beam 3a may have the following dimensions: its upper bearing surface 6 may have a width LH of between about 5 and 7 cm, advantageously about 6 cm; the vertical support zone 70 of the secondary beam, occupied by the hooking members 7c and 7d, may have a width L1 of between approximately 9 and 12 cm, advantageously of approximately 10 cm; in this case, the vertical distance H between the upper bearing surface 6 of the beam and the lower hooking structure 7a can be between 8 and 12 cm, preferably about 10 cm, that is to say substantially equal to the value of the width LI at the base. In this way, the width L1 at the base, which is clearly greater than the width LH at the top of the secondary supporting beam 3a, ensures the self-stability of the secondary supporting beam 3a which itself has a good mechanical strength.

Such secondary support beams 3a according to the invention may have appropriate lengths corresponding to the selected centers of the primary beams 2a and 2b. Thus, lengths of 110 cm, 150 cm, 180 cm can be used to define a range of beams that can be used in the current conditions of making slab formwork. In use, such secondary support beams 3a can be arranged as illustrated in FIG. 1, in a pitch P such that the space between two successive secondary support beams at the level of the upper bearing surfaces 6 is less than About 14 cm. The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof within the scope of the claims below.

52O8FDEP.doc

Claims (5)

1 û Secondary support beam (3a) for slab formwork or the like, intended to be arranged between two primary beams (2a, 2b) to form a modular support planar framework supported by struts (4), in which: secondary supporting beam (3a) comprises an elongate beam body (5) having a bearing upper face (6) and having at its ends two connecting structures (7, 10) for fixing to the respective primary beams (2a, 2b each connecting structure (7, 10) comprises a lower hooking structure (7a) shaped to bear vertically by simply moving downward on a receiving side structure (12d) of the primary beam (2a) according to a vertical support zone (70), and for hooking onto the lateral receiving structure (12d) so as to oppose any axial displacement towards and away from the primary beam (2a), characterized in that what the prop zone (70) has a width (LI) greater than the width (LH) of the bearing upper surface (6) of secondary beam (3a) and extends laterally on either side thereof. 2 û secondary support beam (3a) according to claim 1, characterized in that the distance (H) between the upper bearing surface (6) and the lower hooking structure (7a) is less than or equal to the width (LI) of the vertical support zone (70). 3 û secondary support beam (3a) according to one of claims 1 or 2, characterized in that the lower hooking structure (7a) comprises two hooking members (7c, 7d) spaced laterally one of the other a distance (D) such that they occupy said width (LI) greater than the width (LH) of the upper bearing surface (6) of the secondary beam (3a), and able to engage in a chute lateral (12d) receiving the primary beam (2a). 4 û secondary support beam (3a) according to any one of claims 1 to 3, characterized in that the connecting structure (7) further comprises an upper axial bearing structure (7b) adapted to bear bearing laterally against the primary beam (2a). 5 û secondary support beam (3a) according to claim 4, characterized in that the upper axial bearing structure (7b) comprises two bearing noses (7e, 7f) spaced laterally from each other, and coming directly above the hooking members (7c, 7d) in the longitudinal direction of the secondary supporting beam (3a). 520REDEI'.doc 2923241 12 6 û secondary support beam (3a) according to any one of claims 1 to 5, characterized in that the beam body (5) comprises a central section (8) with a generally shaped cross-section at I, with a vertical central branch (8a), two lower lateral stiffening wings (8b, 8c) and a stiffened upper flaring structure (8d) forming the upper bearing surface (6) of the secondary supporting beam (3a). ), and comprises two attachments (9, 11), each end (9, 11) having a transverse plate (9a) resting in a first face against the end of the central profile (8) and provided with stabilizing gussets ( 9b, 9c) being attached to the lower lateral stiffening wings (8b, 8c) of the central section (8) on either side of the vertical central branch (8a), the second face of the transverse plate (9a) support having the elements of the connection structure (7). 7 û secondary support beam (3a) according to claim 6, characterized in that the transverse plate (9a) of the tip (9) has: - in front view, a width which decreases regularly from the lower structure of hooking (7a) to the upper axial support structure (7b), - in side view, a thickness (E) which decreases regularly from the lower hooking structure (7a) to the junction with the upper structure protruding axial bearing (7b). 20 8 - secondary support beam (3a) according to one of claims 6 or 7, characterized in that the upper flared structure (8d) of the central section (8) comprises a lower box (8e) generally triangular section that s widens since its connection to the central branch (8a) and is connected to two upper lateral wings (8f, 8g) defining an upper groove (8h) open upwards and intended to receive and retain a wood insert (8i) to form the supporting upper face (6) of beam. 9 û secondary support beam (3a) according to any one of claims 6 to 8, characterized in that the central section (8) is extruded aluminum alloy, and the ends (9, 10) are made of aluminum alloy cast aluminum. 30 10 û secondary support beam (3a) according to any one of claims 1 to 9, characterized in that the upper bearing surface (6) of secondary beam has a width (LH) of between 5 and 7 cm, preferably of about 6 cm, the vertical support zone (70) of secondary beam has a width (L1) of about 9 to 12 cm, preferably about 10 cm, and the vertical distance (H) of the lower structure of hooking (7a) and the upper bearing surface (6) is between 8 and 12 cm, preferably about 10 cm. 8 A modular support structure for slab formwork or the like, characterized in that it comprises primary beams (2a, 2b) supporting two by two secondary support beams (3a) according to any one of the following: Claims 1 to 10, the secondary support beams (3a) being spaced apart from one another with a pitch (P) such as the gap between the upper bearing surfaces (6) of two secondary beams (3a) of successive support is less than 14 cm.