FR2739643A1 - COLLABORATING METAL BEAM - Google Patents

Abstract

The beam is made by the cold assembly of two sheet metal profiles (6,9). The inner profile (9) is attached to two vertical side walls (6A,6B) of the outer one. This forms a horizontal transverse partition (12) with a cavity (8) above it which can be filled with concrete. The side walls of the cavity have elements which engage with the cast concrete. The cast concrete is formed either by the in-turned upper edges of the inner profile or by the fixings (10) which join the two profiles together. The profiles are joined so that the cavity formed between them has a depth which allows the concrete to perform essentially under compression while the beam is under load.

Description

The invention relates to a metal beam

  collaborator for the construction of buildings, that is to say a composite beam comprising a metal part and a concrete part which collaborate between them to support a load. The invention relates more particularly to the metal part of a

such beam.

  We can for example use this type of beam to support a

  reinforced concrete floor, which can itself be of the "collaborating" type.

  We then proceed by casting a concrete slab on a ribbed sheet,

  which serves as formwork and resistant frame.

  The ribbed sheet panels are supported at their ends on beams, which form a network for supporting the floor such as

shown in Figure 1.

  Beams are usually made of I-shaped hot-rolled steel beams 1. When the concrete is poured, it is poured at the same time at the same time.

  ribbed sheets and on the upper faces 2 of the beams 1.

  To ensure effective mechanical collaboration between the beams 1 and concrete (not shown), is fixed on these faces 2 concrete connectors (or "connectors-concrete" 3), in the form of short stems; preferably, the end of these rods is prominent for

  ensure better bonding of the concrete.

  Thus, thanks to these connectors-concrete 3, cast concrete is no

  only solidarity with the ribbed sheets but also beams 1 themselves

  same through the connectors-concrete 3 and the beams as well

  formed are called "collaborating".

  Concrete therefore reinforces the beams 1 by this collaborative effect and works at this location essentially in compression; the part of the concrete slab that collaborates with the beam 1 is called "compression table". According to this conventional design of beam collaborante, the function of support of the beam is ensured by both the beam I in I and

  by the floor concrete slab (not shown).

  This collaborative floor construction method on a hot working beam has several disadvantages: - the connectors-concrete 3 are expensive and their installation is expensive - except to add additional formwork elements, it is not possible to choose the thickness of the compression table independently of that of the slab, nor to vary this thickness along the beam - to make beams of variable thickness profile. It is not possible either to obtain for sure a beam whose axes

  Neutrals present the ideal position.

  - on the same site, you need as many types of beams to hot as there are beams of different characteristics to ask and build.

  The object of the invention is to avoid these disadvantages.

  The subject of the invention is a collaborating metal beam made by assembling cold sections of metal sheets, characterized in that it is delimited at least by two approximately parallel vertical sheet metal side walls forming between them an opening from above to the interior of the beam, and in that said side walls are interconnected by an internal section such that the upper part of said side walls and said internal profile form the walls of a cavity intended to receive concrete through said opening. towards the inside of the beam, and in that the walls of said cavity are provided with

  means to collaborate with the concrete.

  Said cavity therefore forms a formwork for concrete.

  After casting and setting of the concrete, the beam comprises a purely metallic lower part which works essentially in traction and an upper part essentially made of reinforced and worked concrete which works

  in compression and called "compression table".

  The invention therefore also relates to the metal beam according to

  the invention containing concrete in said cavity.

  Depending on the load that the beam must be able to support, one can choose the thickness of the compression table by adapting the depth of the cavity, ie by adapting the height of fixing of the internal profile

  on the side walls at the time of assembly of the beam.

  It then becomes possible to optimize the beam according to the floors to be supported, and to easily obtain the ideal position of the neutral axes. On the same site, from the same profiles, we can realize

  beams of very different characteristics (range, maximum load).

  In the case of beams for supporting collaborating floors, it is possible to proceed as in the prior art, in particular by casting in a single operation the concrete in the beam and the concrete on ribbed sheets.

of the floor.

  In this case, the characteristics of the collaborating beam according to the invention can be determined independently of the thickness of the concrete slab forming the floor without adding additional formwork elements. Conversely, it is also possible to realize the beams quite independently of the floor itself, so not to pour concrete, at first, only in the beams; in a conventional arrangement, it is then possible to maintain reinforcements waiting in the beams. When the beams are made independently of the collaborating floor, it is advantageous to reduce the provisional shoring, since, on the one hand, when pouring into the beam, the beam only has to support its own weight, and that on the other hand, when pouring the floor, the beam - whose concrete is dry - is much more resistant. It is also possible, from the beams according to the invention, prefabricated collaborating beams, used for example to support

prefabricated floors.

  An advantage of the invention lies in the ease of assembly of the beam directly on the construction site from cold sections of sheet metal cut to the required dimensions; the profiles are assembled, for example using self-tapping screws, nails or

rivets.

  Another advantage is to simplify the supply of the site; where it would have been necessary, using conventional solutions, to supply hot-profiled beams with different characteristics (height, thickness of steel), the same cold sections

  can be used for beams of very different characteristics.

  According to complementary features of the invention, the beam-concrete collaboration can be ensured in the following manner: by upper edges of said side walls and / or said

  internal profile, these flanges penetrating into the cavity.

  by means of assembly of said inner profile with said

  side walls that protrude inwardly of said cavity.

  These assembly means may be for example screws, nails or rivets that protrude into the cavity and, thus being embedded in the concrete after casting, also serve as means

collaboration.

  It can therefore be seen that, according to the invention, there is no longer any need to pose

additional connectors.

  According to a preferred embodiment of the invention, said inner profile is U-shaped or E whose opening is turned upwards; the side walls of the beam are then secured to the legs of the U or E. According to a particular embodiment of the invention, said inner profile has a suitable shape, particularly bent, to vary the

  depth of said cavity along the beam.

  It then becomes possible and easy, according to the invention, to obtain compression table beams of variable thickness along the beam,

  whose profile is adapted to the distribution of the efforts to be supported.

  The invention also makes it possible to solve a problem generally posed by the superposition of several networks of beams, illustrated here.

as following.

  We know that for a collaborating floor, the maximum reach

admissible is of the order of 4 m.

  To support this type of floor, it is necessary to have a network

  beams at least 4 m apart.

  If this is not the case, as indicated in FIG. 1, a network of secondary beams is installed on the existing network, or network of main beams 1, the secondary beams being less than 4 m apart.

  each other to be able to sink a collaborating floor.

  This solution, which involves two networks of superimposed beams, considerably increases the overall thickness of the floor, which is

often a disadvantage.

  This large thickness can, for example, annoy architects, who generally want to build the maximum number of floors in the minimum.

height.

  In order to avoid this drawback, it is then possible to proceed as shown in FIG. 2, fixing for example by angles 5 the end of the secondary beams (beams 1) on the side of the beams.

main 4.

  But this method of fixing the secondary beams on the beams

major is expensive.

  Another object of the invention is a beam of the secondary beam type which

  avoids the aforementioned drawbacks.

  The invention therefore also relates to the beam according to the invention described above, characterized in that it is further provided with means for collaborating with a support, in particular on a main beam, adapted to rest said internal profile directly on

said support.

  According to additional features of the invention, said means comprise, at at least one end of the beam, a longitudinal protrusion of said inner section with respect to said side walls, said overtaking being intended to rest directly on

  said support, in particular a main beam.

  said means comprise a notch made in the lower part of said side walls, said notch being adapted to allow said internal section to rest at this point directly on said

  support, including a main beam.

  This notch can also be made at the end of the beam, or

  any place where it is a matter of putting the beam on a support.

  The invention will be better understood on reading the description which will

  follow, given by way of example, and with reference to the appended figures in which: - Figure 1 is a perspective view of two superposed networks of beams to support a floor, the upper beams being

  equipped with connectors-concrete according to the prior art.

  FIG. 2 is a perspective view of a method of attachment according to

  the prior art of a secondary beam on a main beam.

  FIGS. 3A, 3B, 3C, 3D are respectively perspective, top, end and side views of a beam according to the invention. FIG. 4 is a side view of a beam according to the invention

  having a cavity of variable depth in the direction of the length.

  - Figures 5 to 12 are end views of beams according to other variants of the invention; the hatched portion of FIG. 11 further represents a section of a supported cooperating concrete floor

by the beam.

  FIGS. 13A, 13B, 13C are respectively perspective, top and end views of a beam according to the invention provided with means for resting the end of the beam on a support, here a

  longitudinal extension of the internal section.

  FIG. 14 describes how the beam of FIG. 10 can be laid

  at one end on a main beam.

  FIG. 15 represents a variant of the support means of the beam according to the invention, here an indentation practiced in the part

  lower side walls, and the implementation of this variant.

  Examples of embodiments and uses will now be described.

beams according to the invention.

  The beam is made by assembling cold sections of metal sheets. The assembly of the profiles that form the beam according to the invention is designed to provide all along the upper portion of the beam a cavity for receiving concrete through an opening in the

upper side.

  The cavity is provided with collaboration means with the concrete, such as flanges of the profiles, assembly screws or bosses making

  protruding into the cavity.

  For example, reference is made to FIGS. 3A to 3D.

  There are two types of cold-rolled sections, generally made of steel: an "outer" section 6 of parallelepipedal cross-section having a U-shape with upper flanges 7A, 7B returning towards each other without joining one another: so we basically have a wall

  lower and two side walls 6A, 6B approximately parallel.

  On the upper part, the distance between the edges 7A, 7B household

  an opening 8 to the inside of the outer profile.

  an "internal" section 9, U-shaped, the width of which is adapted to be inserted into the outer profile 6 and to join the two walls

  6A, 6B of the external section 6.

  As shown in FIGS. 5, 6 and 7, the internal profile 9 comprises

  preferably reentrant upper flanges 10A, 10B.

  The two sections 6, 9 are cut to the required length of the beam.

  The inner profile 9 is inserted into the outer profile 6 as shown in FIGS. 3A and 3C, preferably with the U-shape facing upwards.

internal profile 9.

  The height of attachment of the internal profile 9 in the outer profile 6 determines the depth of an internal cavity 12, so the thickness of the

compression table of the beam.

  The desired thickness of the compression table of the beam is determined in a manner known per se, in particular as a function of the stresses to which the beam must be able to withstand and as a function of

  the desired position of the neutral axes of the beam.

  The two profiles 6 and 9 are made integral, by a method of fixing

  known in itself, for example by rivets 10.

  As shown in FIG. 5, it is preferable for the assembly of screws 11 which project towards the inside of the beam to

  contribute to the bonding of the concrete.

  In particular, self-tapping screws can be used.

  It is advantageous to assemble the beam on the site itself

of construction.

  Thus, a beam is provided in its upper part with an internal cavity 12 open on the upper face of the beam by

the opening 8.

  This cavity 12 is intended to receive concrete with its reinforcements,

  for which it will serve as formwork.

  Concrete is poured into the cavity 12.

  When the beam will be in use, the hardened concrete (not shown) in the cavity 12 will work essentially in compression and will constitute

therefore the compression table.

  The formwork formed by the cavity 12 then collaborates with the concrete.

  According to the invention, the cavity 12 comprises beam-concrete collaboration means. The means of collaboration of the beam with the concrete here comprise the reentrant upper flanges 7A, 7B of the external section 6 (FIGS. 3A to 3C, 5 and 6), and / or the flanges 10A, 10B of the internal section 9 (FIGS. 7) and / or the screws 11 which project towards the inside of the beam (FIGS. 5 and 7). According to other variants of the invention not shown here, the beam-concrete collaboration means may comprise bosses formed in the lateral walls 6A, 6B of the external section, or in the

internal profile 9.

  It was thus realized a collaborating beam, starting from cold sections

  and avoiding expensive installation of connectors-concrete.

  It is also very easy to obtain the required compression table thickness by adapting the fixing of the internal profile 9 in the external profile 6

  to obtain the required cavity depth 12.

  It is even possible to obtain a compression table beam of variable thickness along the beam by using an internal profile configured for this purpose: FIG. 4 represents an upwardly curved inner profile beam 9. It is also possible to assemble internal curved profile beams towards

the bottom.

  According to the invention, from the same sections 6, 9, it is possible to produce several types of beams on the same site, by varying

  the height of attachment of the internal profile 9 in the external profile 6.

  The beams according to the invention are advantageously used in

  construction for supporting floors.

  In the case where the beam is used to support a collaborating floor,

  can proceed as follows.

  Before pouring concrete into the beam, a network of

  support beams of the floor.

  Between the beams are placed ribbed sheets adapted to the

  construction of collaborating floors.

  The sheets rest at their ends on the upper flanges 7A, 7B of the beams without covering or masking the opening 8 towards the inside of the

  cavity 12 to fill with concrete of each beam.

  As needed, fittings and screens are available

  of reinforcement, including in cavity 12.

  Concrete is poured into both the beams and the sheets.

  After drying the concrete, we then obtain a collaborating floor

  supported by the collaborating parties according to the invention.

  Without departing from the present invention, it is possible to use other types of profiles for producing a beam according to the invention: FIG. 7 describes a beam identical to the beam previously described, with the difference that the external section 9 has outward edges therefore not collaborating; this provision facilitates the insertion of the

  internal profile in the external profile.

  - Figure 8 describes a beam made by the assembly of four profiles also more easily assembled: two L-shaped profiles for the side walls, the base of the L serving as upper edge, connected by two U-shaped profiles, one 9 internal, the other 13 at the base of the beam. - Figures 9 and 10 describe a beam made from two sections S, 14A and 14B, connected by an inner section 9 U. The ends 15 of the S-shaped are slightly folded on themselves to hang on the lower part of the beam of the elements,

  in particular ceiling construction elements.

  FIG. 11 represents a variant of the beam of FIG. 9, where an additional U-shaped profile has been added to the lower face of the beam to reinforce the beam in the portion subjected to stress in FIG.

  traction and to prevent buckling of the side walls.

  FIG. 11 also partially shows: ribbed plates 16 resting on the upper flanges 7A, 7B of the beam, leaving the opening 8 open in the beam; and, in shaded area, concrete 17 filling the cavity of the beam and covering the

  sheets 16 to form a collaborating floor.

  FIG. 12 shows a variant of the beam of FIG. 11, where the two U-shaped profiles are replaced by S-shaped profiles 9 '. The advantages of fixing which the beam according to FIG. invention, especially for the realization of networks

secondary beams.

  Advantageously, the beam is rested on a support by

  via the internal profile itself.

  It suffices, for example, to provide, at the time of cutting of the profiles 6, 9, a length of the inner profile 9 greater than that of the outer profile 6, so that after assembly, the inner profile 9 protrudes at at least one end. 18 with respect to the end of the outer profile 6,

  as shown in FIGS. 13A, 13B and 13C.

  In this way, it is possible to base the end of the beam according to the invention by means of the protruding end 18 of the internal profile 9, as represented in FIG. 14; the beam according to the invention is

  here supported by a main beam 4 identical to that of Figure 1.

  Thanks to this arrangement made possible by the actual structure of the beam according to the invention, it is possible to limit the overall thickness of the floors even when it is necessary to mount several superposed networks of beams to support a floor, and while maintaining ease of assembly by simply removing the beams on each other; there is no need to resort to complex fastening systems and

  expensive, as in the prior art (Figure 2).

  Other variants relating to the support means of the beams according to the invention offer the same advantages, as that shown in FIG. 15, where an indentation 19 has been made in the side walls 6A, 6B, here at the end. of the beam, to also make it possible to rest the beam by means of the internal section,

  in particular to limit the overall thickness of a floor.

Claims (9)

  1I.- Collaborative metal beam made by assembling cold sections of metal sheets (6, 9), characterized in that it is delimited at least by two approximately parallel vertical sheet metal side walls (6A, 6B) between them opening (8) from the top to the inside of the beam, and in that said side walls (6A, 6B) are interconnected by an inner profile (9) so that the upper part of said side walls (6A , 6B) and said inner profile (9) form the walls of a cavity (12) for receiving concrete through said opening (8) towards the inside of the beam, and in that the walls of   said cavity (12) is provided with means for collaborating with the concrete.   2. Beam according to claim 1 characterized in that said means for collaborating with the concrete comprise upper flanges of said side walls (7A, 7B) and / or said inner section (10A, 10B),   said flanges penetrating inwardly of the cavity (12).   3. Beam according to claim 1 or 2 characterized in that said means for cooperating with the concrete comprise means for assembling said inner section (9) with said side walls (6A, 6B).   protruding inwardly of said cavity (12).   4. Beam according to any one of the preceding claims   characterized in that said inner section (9) is U-shaped or E-shaped   whose opening (8) is turned upwards.   5. Beam according to any one of the preceding claims   characterized in that said inner profile (9) has a suitable shape, particularly bent, to vary the depth of said cavity (12) the along the beam.   6. Beam according to any one of the preceding claims   characterized in that it is provided with means for collaborating with a support, in particular on another beam (4), adapted to rest   said internal profile (9) directly on said support.   7. A beam according to claim 6 characterized in that said means comprise, at at least one end of said beam, a longitudinal extension (18) of said inner section (9) relative to said side walls (6A, 6B), said exceeding (18) being intended to rest directly on said support, in particular a main beam (4). 8.Butter according to claim 6 characterized in that said means comprise a notch (19) formed in the lower part of said side walls (6A, 6B), said notch (19) being adapted to allow said inner section (9) of to rest at this place   directly on said support, in particular a main beam (4).   9. Beam according to any one of the preceding claims   characterized in that said cavity (12) contains concrete.