FR3057289B1 - BUILDING ELEMENT FOR STEEL-CONCRETE MIXED BEAM, BUILDING ASSEMBLY AND CONSTRUCTION KITS - Google Patents

Abstract

Structural member (1) for composite steel-reinforced concrete beam comprising a metal beam (10) of U-shaped cross section, formed by a bottom (11), two side walls (12) and two flanges upper ones (13) extending longitudinally outwards and, an armature cage (20) having longitudinal reinforcing elements (21), said reinforcing cage (20) being disposed inside said beam metal element (10), characterized in that said construction element (1) further comprises transverse metal elements (30) fixed to said upper flanges, at least some of said transverse metal elements (30) being fixed to said reinforcing cage ( 20).

Description

Structural element for steel-reinforced concrete composite beam, construction kit and construction kits

Field of the invention

The field of the invention is that of the reinforced concrete construction, in particular that of mixed steel-reinforced concrete structures. The invention more specifically relates to a construction element for a composite steel-reinforced concrete beam, a construction assembly and drifting construction kits.

Previous Art

Mixed steel-concrete structures exploit the favorable and complementary characteristics of steel and concrete. In particular, the steel withstands tensile stresses and has sufficient ductility allowing plastic deformations while the concrete is resistant to compressive forces and has good fire resistance. In addition, at equal lift, a purely steel structure is lighter and has a higher cost while a purely concrete structure is heavier and has a lower cost.

The mixed steel-reinforced concrete beams comprise two components: a first component of reinforced concrete, ie made of concrete and metal reinforcements, and a second component consisting of a metal section. To improve the fire resistance, this profile can be coated with a material such as an intumescent paint, flocking or be partially coated with the concrete of the first component.

Most composite steel-reinforced concrete beams of the prior art certainly allow to have beams advantageously combining the properties of steel and concrete but are difficult to implement. Indeed, the use of such beams generally involves the positioning of the metal section on at least two points of support, then the pouring of the concrete and finally the stripping after the setting of the concrete: this sequential sequence of steps has a negative impact direct on the duration of the works. According to other embodiments, the composite steel-reinforced concrete beam is prefabricated and is directly positioned on at least two support points: such prefabricated beams are very heavy which leads to additional difficulties or even unnecessary risk taking when their transport or when lifting them.

To overcome these problems, a construction element consisting of an elongate box, bounded by a metal wall having an upwardly open face, containing a metal reinforcement cage, may be used. Such a technique has notably been described in the patent application published under the number FR2925088 A1. The advantage of this technique is to have elements of short length constructions, notably avoiding the use of transport authorizations on the road network. , and to be able to connect end to end these in order to obtain beams of long reach. Such an end-to-end connection is made by welding or bolting metal plates on either side of the respective bottoms and the respective walls provided on such building elements, which increases the costs of implementation.

According to this technique, the concrete can be poured directly into the box by at least partially embedding the reinforcing cage so as to produce two coaxial beams, respectively an inner reinforced concrete beam and a metal outer beam. The caisson thus has a dual role: before pouring concrete, the caisson plays the role of concrete formwork; after the setting of the concrete, the box plays the role of frame elements of the composite steel-reinforced concrete beam thus formed.

The technique according to FR2925088A1 also has the disadvantage of requiring the use of stiffening gussets placed in the lower corners at the bottom of the box to ensure proper positioning of the metal reinforcement cage, in particular by allowing to maintain a distance between the lower part of the metal reinforcement cage and the bottom of the box. The use of these gussets increases the time of installation labor and has an almost zero interest for the mechanical properties of the composite steel-reinforced concrete beam. The building element according to this prior art further has on at least one side, a longitudinal plate fixed along the upper edge of a side wall of the box and extending outwardly so as to constitute a support for the less a horizontal formwork plate for the realization of a slab. This has the advantage of being able to cast in a single grip the useful concrete for the composite steel-reinforced concrete beam and for a slab above it. A plurality of anchor pins, including Nelson type rods, however, must be placed on each longitudinal plate fixed along the upper edge of at least one side wall to ensure good bonding between the steel-concrete composite beam. armed and the slab intended to overhang, which further complicates the implementation of this technique.

In addition, according to this technique, the upper edges of the walls may be caused to deform under the weight of the concrete during casting thereof.

Objectives of the invention The object of the invention is to overcome at least one of the disadvantages mentioned above. The object of the invention is, in particular, to propose an improved structural element for a composite steel-reinforced concrete beam that makes it possible to reduce the number of stages of implementation of a composite steel-reinforced concrete beam on a construction site and authorizing the implementation of easy, fast and safe work of the latter while maintaining a classic mode of pouring concrete

Another object of the invention is to provide an improved structural element for composite steel-reinforced concrete beam allowing the resumption of shear stresses between the concrete and the metal component of such a beam.

Another object of the invention is to provide an improved structural element for a solid and non-deformable steel-concrete composite beam, particularly during the transport or pouring phases of concrete.

Another object of the invention is to provide an improved structural element for composite steel-reinforced concrete beam in which the use of material has been optimized.

Another object of the invention, at least in some embodiments, is to provide an improved building element having increased fire resistance.

Another object of the invention, at least in certain embodiments, is to provide an improved structural element for a composite steel-reinforced concrete beam that can be connected end-to-end with other elements of the same type.

Another object of the invention is to provide a construction kit and construction kits comprising at least one element and or assembly for a composite steel-reinforced concrete beam according to the invention.

SUMMARY OF THE INVENTION The invention relates to a construction element for a composite steel-reinforced concrete beam comprising a U-shaped cross-section metal beam formed of a bottom, two lateral walls and two upper flanges. extending longitudinally outwards and, a reinforcing cage having longitudinal reinforcing elements, said reinforcing cage being disposed inside said metal beam, characterized in that said building element further comprises transverse metal members attached to said upper flanges, at least some of said transverse metal members being attached to said reinforcing cage. Unless otherwise specified, within the meaning of the present invention, "longitudinal" or "longitudinally" refers to the direction in which the beam is elongated. Conversely, "transverse" or "transversely" refers to a direction substantially orthogonal to both side walls. In addition, "inside" or "internally" refer to the space substantially delimited by the bottom and the two side walls of the beam in the case where the latter was fictitiously closed at its ends and on its upper part. Conversely, "outside" or "outside" refers to the complementary space of the interior space.

For the purposes of the present invention, the expression "composite beam" designates a "composite steel-reinforced concrete beam".

The bottom and the two side walls of the metal beam are not only intended to form concrete form walls of a composite beam but also intended to form frame elements of the composite beam. This metal beam of U-shaped cross section may be obtained by welding side and bottom walls or by folding.

The two upper flanges extending longitudinally outward allow in particular to rest thereon elements for the formwork of a slab, including reinforced concrete slabs or cooperating bins. During the implementation of the composite beam and the overhanging slab, the concrete can then be poured in a single take, which has the dual interest of ensuring a saving of time for the implementation and ensuring the continuity of the mechanical properties of the concrete between the composite beam and the overhanging slab by the resumption of the longitudinal shear between the beam and the slab. The reinforcing cage is intended to form all of the metal reinforcements of the reinforced concrete of the composite beam. The reinforcement cage comprises longitudinal reinforcement elements, the role of which is to take up the tensile forces on the composite beam.

The transverse metallic elements have a multiple role. Being fixed to said two upper flanges of the metal beam, they prevent deformation of the metal beam, especially during the transport and pouring phases of the concrete. After pouring the concrete, and thus once the mixed beam implemented, they allow to take the shear stress between the concrete component and the metal component of the beam.

It will be noted that these transverse metal elements will be provided spaced apart by a variable spacing distance according to the constraints that the composite beam, which will be made by association of several building elements according to the invention, will be subjected to. On the same beam, this distance may vary from one building element to another. It may also be envisaged to provide variable spacings between the transverse elements on the same building element.

Preferably, said transverse metal elements have at least one horizontal surface fixed to said two upper flanges and at least one vertical surface.

They facilitate the anchoring of the composite beam in the overhanging slab, particularly when they have such a horizontal surface.

Said said transverse metal elements fixed to said reinforcement cage make it possible to ensure a good positioning of the metal cage and to overcome the additional use of gussets. Preferably, said transverse metal elements are chosen from the group consisting of: solid metal bars of rectangular cross-section, solid metal bars of square or circular cross section, U-shaped metal profiles, "L" shaped profiles ". The elements of this group have the advantage of having a simple geometric shape, to have a low cost, and to be easily machinable / commercially accessible.

According to a preferred embodiment of the invention, said construction element further comprises a flame retardant material disposed on at least a portion of the bottom and / or on at least a portion of the side walls inside said metal beam. The flame retardant material makes it possible to protect at least some critical elements of the reinforcement cage against the high temperatures during a fire and thus to preserve the mechanical properties of the reinforced concrete of the composite beam.

According to a particular embodiment of the invention, said construction element comprises at least one of its ends connecting means fixed on the bottom and / or on the side walls inside the metal beam, said connecting means being able to make contact with the bottom and / or the side walls of any other element of construction according to the invention. The connecting means allow easy interlocking by guiding the construction element on which they are attached to another construction element according to the invention. No fixation of the connecting elements is necessary on the other construction element: indeed, once the mixed beam implemented, the concrete ensures adhesion between the fixing means and the bottom and / or the side walls of the other building element. Advantageously, said connecting means are chosen from the group consisting of: metal bars, in particular high-adhesion metal bars, "U" -shaped profiles, "L" shaped profiles. The elements of this group have the advantage of having a simple geometric shape, to have a low cost, and to be easily machinable / commercially accessible. The invention also relates to a building assembly comprising a construction element as described above, and a metal formwork for a possibly reinforced concrete post, said metal formwork being fixed to said bottom of said building element and communicating with said building element. thanks to an opening disposed on said bottom. The advantage of such a construction set is that concrete can be poured in a single take to form a mixed beam - mixed post assembly. In addition, it ensures a continuity of mechanical properties of concrete between the composite beam and the mixed post. The invention further relates to a construction kit comprising at least two building elements according to the invention, capable of being assembled end to end by covering at least some of said longitudinal reinforcing elements of their respective reinforcing cage or by coaxial insertion of a small additional reinforcement cage between their respective cages. The invention furthermore relates to a construction kit comprising at least one construction element according to the invention and at least one building assembly according to the invention, the at least one building element being able to be assembled end-to-end by overlap at least some of the longitudinal reinforcing elements of said at least one construction element with some of said longitudinal reinforcing elements of said at least one building assembly.

List of Figures Other features and advantages of the invention will emerge more clearly on reading the following description of particular embodiments, given as simple illustrative and non-limiting examples, and the appended drawings, in which: Figure 1 shows a cross-sectional view of a building element according to the invention; FIG. 2A shows a perspective view of the construction element of FIG. 1, according to an embodiment using transverse metal elements being solid metal bars of square section; FIG. 2B shows a perspective view of the construction element of FIG. 1, according to an embodiment using transverse metal elements being "L" shaped profiles; - Figure 3 shows a cross-sectional view of a composite beam implemented using a construction element according to the invention, comprising a fireproof element, on which has been placed pre-slabs; - Figure 4 shows a cross-sectional view of a building assembly consisting of a building element according to the invention and a metal formwork for composite steel-concrete post; FIG. 5A represents a perspective view of a construction element according to the invention having connecting means capable of making contact with the bottom and / or the walls of any other construction element according to the invention; - Figure 5B shows a construction element according to Figure 5 A and a construction element according to Figure 2B.

Description of Detailed Embodiments of the Invention

With reference to FIGS. 1, 2A, 2B and 3, the construction element 1 for a steel-reinforced concrete composite beam 5 comprises a metal beam 10 of "U" -shaped cross-section, a reinforcement cage 20 and elements transverse metal 30.

The metal beam 10 is formed of a bottom 11, two side walls 12 and two upper flanges 13 extending longitudinally outwardly. The upper flanges 13 make it possible to base the pre-slab elements 65. Concrete 60 can then be cast in a single plug filling on the one hand the construction element 1 to form a composite steel-reinforced concrete beam 5 and a slab of concrete 6 overlooking it.

The reinforcing cage 20 comprises metal rods 21 extending longitudinally and metal frames 22 extending transversely. It is shaped to meet the criteria according to standard NF-EN 10080. The metal rods 21 allow in particular the recovery of bending moments of the composite beam 5. The metal frames 22 allow in particular the recovery of shear forces of the composite beam 5. The upper part of the reinforcement cage 20 protrudes outside the metal beam 10, which allows part of the slab to participate in the bending of the beam.

Two embodiments of the transverse metal elements 30 are shown in FIGS. 2A and 2B. The transverse metal elements 30 are attached to the beam 10 to the reinforcement cage 20 by welding. The reinforcing cage 20 is welded to certain vertical surfaces 32 of the metal elements 30 so as to leave a minimum distance between, on the one hand, the bottom 11 of the construction element 1 and the metal armature 20, and on the other hand the side walls 12 of the construction element 1 and the metal armature 20, such that the armature 20 has a good lower and lateral coating in the composite beam 5.

Figure 2A shows transverse metal members being solid square bars of square section. The solid metal bars of square section have a horizontal surface 31 fixed to the two upper flanges 13 to prevent deformation of the metal beam 10. Once the construction elements associated with each other to form a composite beam as shown in FIG. 4, the metal bars will allow to take up the longitudinal shear between the metal component and the reinforced concrete component of this beam and thus optimize the mixed behavior of this beam. The bars being full they have the advantage of having excellent resistance to bending in the direction of their length.

Figure 2B shows transverse metal members 30 being "L" shaped profiles, also referred to as "90 ° corner angles". The transverse metal elements 30 have a horizontal surface 31 fixed to the two upper flanges 13 to prevent deformation of the metal beam 10. The transverse metal elements 30 also have a vertical surface 32. Once the construction elements associated with each other for to form a composite beam as shown in Figure 4, these brackets will resume the longitudinal shear between the metal component and the reinforced concrete component of the beam and optimize the mixed behavior of the beam. The 90 ° angle angles have the advantage of having a low cost for an optimized amount of material.

According to the embodiment of Figure 3, the construction element 1 has on its bottom 11 and partially at its walls 12 a flame retardant material 60 (plaster, plate of limestone or silico-limestone, cement ...) . The fire-retardant material 60 particularly protects against fire the lower part of the reinforcing cage 20, this part playing an essential role for the resistance of the composite beam 5 at the bending moment.

With reference to FIGS. 5A and 5B, the construction element 1 comprises at one of its ends connection means 40 fixed to the bottom 11 and to the lateral walls 12 inside the metal beam 10. The means connecting members 40 are able to make contact with the bottom 11 and the walls 12 of another construction element 1. The connecting means 40 are fixed to the first construction element 1 by welding or by bolting and allow easy interlocking by guiding. of the first construction element 1 to which they are attached to the other construction element 1. No fixation of the connecting elements is necessary on the other construction element: in fact, once the composite beam has been implemented, the concrete ensures the transfer of forces between the fastening means 40 and the bottom 11 and the side walls 12 of the other construction element 1. At the interface between the first element e construction 1 fitted end-to-end with the other construction element 1, the composite beam once implemented has a mechanical behavior of reinforced concrete.

With reference to FIG. 4, the building assembly 2 comprises a building element 1 according to the invention, and a metal formwork 5 for a steel-concrete composite post.

The metal form 5 may be circular, rectangular, square or any other suitable form. It is fixed to the bottom 11 of the construction element 1 by bolting or welding and communicates with the construction element 1 through an opening 14 disposed on the bottom 11 of the construction element 1. The advantage of using the building assembly 2 is that concrete can be poured in a single tap to form a mixed beam-mixed column assembly. In addition, it ensures a continuity of mechanical properties of concrete between the composite beam and the mixed post.

Claims (7)

1. Construction element (1) for composite steel-reinforced concrete beam comprising a metal beam (10) of U-shaped cross section, formed by a bottom (11), two side walls (12) and two upper flanges (13) extending longitudinally outwardly, and one reinforcing cage (20) having longitudinal reinforcing elements (21), said reinforcing cage (20) being disposed within said metal beam (10), characterized in that said building element (1) further comprises transverse metal elements (30) fixed to said upper flanges, at least some of said transverse metal elements (30) being fixed to said cage of armature (20), said transverse metal members having a horizontal surface (31) attached to said two upper flanges (13) and a vertical surface (32) and forming "L" shaped profiles. 2. Construction element (1), according to any one of the preceding claims, comprising a flame retardant material (50) disposed on at least a portion of said bottom (11) and / or on at least a portion of said side walls (12) inside said metal beam (10). 3. Element of construction (1) according to any one of the preceding claims, comprising at least one of its ends connecting means (40) fixed on said bottom (11) and / or on said side walls ( 12) inside said metal beam (10), said connecting means (40) being able to make contact with the bottom and / or the side walls of any other element or assembly of construction according to one of the preceding claims . 4. Element of construction (1) according to claim 3, characterized in that said connecting means (40) are selected from the group consisting of: metal bars, U-shaped profiles, shaped profiles. "L". 5. Construction assembly (2) comprising a construction element (1) according to any one of claims 1 to 4, and a metal formwork (5) for possibly reinforced concrete post, said metal formwork (5) being fixed to said bottom (11) of said building element (1) and communicating with said building element (1) through an opening (14) disposed on said bottom (11). 6. Building kit comprising at least two building elements (1) according to any one of claims 1 to 5, characterized in that said at least two building elements (1) are capable of being assembled end-to-end by overlap at least some of said longitudinal reinforcing elements (21) of their respective said reinforcing cages (20) or by coaxial insertion of a small additional reinforcing cage between their respective cages (20). 7. Construction kit comprising at least one building element (1) according to any one of claims 1 to 5 and at least one building assembly (2) according to claim 7d, characterized in that said at least one element of construction (1) is capable of being assembled end-to-end by overlapping at least some of said longitudinal reinforcing elements (21) of said at least one building element (1) with some of said longitudinal reinforcing elements (21) of said at least one building set (2).