FR2833632A1 - Composite pillar for building construction has profiled cylindrical outer sleeve with inner frame fixed to it at ends - Google Patents

Abstract

The composite pillar for a building has an outer sleeve (2) which is hollow cylindrical and made as a steel profile. It has an axial metal frame extending longitudinally (12) inside the sleeve, with a fixing (4) at one end (3) for connection to a beam. An abutment plate (6) is positioned at the other end. the interior of the sleeve is divided by the frame to form compartments filled with cement.

Description

<Desc / Clms Page number 1>

 Prefabricated composite post for the construction of a vertical load-bearing structure of a building composed of at least one steel profile, hollow cylindrical.

 The present invention relates to a prefabricated composite post for the construction of a vertical load-bearing building structure, composed of at least one hollow cylindrical steel profile.

 Vertical load-bearing structures for buildings are subject to significant fire resistance constraints and, due to their complexity, pose problems of manufacture and assembly on site. In particular, posts based on hollow profiles and not protected against fire have a low intrinsic resistance during a fire. Different solutions make it possible to respond to fire constraints and thus increase the fire resistance of the columns of the supporting structures.

 One of these fire protection techniques is based on the installation of insulation on the external face of the post. Current methods consist either in fixing insulating plates, or in placing or spraying an insulating material on the surface. In both cases, the fire resistance of the post will depend on the thermal properties of the insulation used and the massiveness factor of the steel profile constituting the frame of the post. This type of protection is for example described in particular in the documents JP2000045418, JP54073415.

 In this configuration, the service loads at room temperature are taken up by the steel profile of the post. The same is true in the case of a fire, but when the steel loses its mechanical strength, the post can no longer withstand the corresponding service loads and its ruin occurs quickly.

 This type of protection is, in general, implemented on site in order to avoid, for example, a deterioration of the insulating layer during transport on site in the case of an implementation off the site. It should be noted that the effectiveness of the protection is directly linked to the quality of its implementation on the steel profile of the post. Consequently, a correct placement of the insulation, without defect, requires, under site conditions, a lot of care and attention as well as a certain qualification of the workers. These conditions penalize the yield and the cost of the supporting structure.

 Another fire protection technique for posts based on hollow sections consists in filling the steel section with concrete. The fire resistance of the composite steel-concrete post varies depending on whether the concrete is fitted with reinforcing bars or not.

<Desc / Clms Page number 2>

This type of protection is notably described in documents GB1507450, JP09041489, JP08129055.

 At room temperature, the steel profile constitutes the main load-bearing element.

On the other hand, during the fire, the participation of steel in the resistance of the post decreases over time and the rise in temperature. During this process, stress redistribution takes place between steel and concrete; the fire service charges are then taken up by the concrete core.

 In most cases, the mixed posts are assembled and then loaded with concrete on site. The implementation steps on site are as follows: the hollow sections are mounted on site, any reinforcement is placed inside the hollow sections and the post can then be filled with concrete. This manufacturing requires a series of different operations, resulting in a loss of time and money. In addition, it is also dependent on weather conditions which can also cause delays in construction.

 The two types of protection can be combined, for example, and in particular, in documents JP11303418, JP08284531.

 The object of the invention is to overcome the drawbacks mentioned above by proposing a prefabricated composite post for the construction of a vertical bearing structure of a building composed of at least one cylindrical steel section having a guarantee of fire resistance in accordance with the regulations and being able to be assembled and assembled mechanically with beams of the standard profile type, for example, in 1 or in H. In addition, this composite post, of aesthetic quality, is economically interesting thanks to an industrial factory prefabrication.

 The object of the invention is a prefabricated composite post for the construction vertical structure of a building composed of at least one hollow cylindrical steel profile, characterized in that it comprises, a cylindrical metallic profiled external envelope, a metallic core axial, longitudinal, a fixing means located at one of its ends to ensure a connection with at least one beam of the building structure, a support and connection plate located at the other end, the internal space of the the envelope being divided by the core, into separate zones, each of the zones being partially or completely filled with concrete and / or insulating material.

 The other characteristics of the invention are: - the cylindrical envelope is of polygonal section, preferably square or rectangular, or circular.

<Desc / Clms Page number 3>

 - the axial, longitudinal metallic core is a cylindrical hollow profile.

- The fixing means with at least one beam of the building structure is composed of quadrilateral plates joined by one of their side to form a star profile.

 - the star profile carries, at the end, a polygonal plate hollowed out in its central part.

- the plate is a square plate, pierced in its center, with a shaped hole corresponding to the section of the outer envelope.

- The fixing means, star profile, is a means of centering the metal core relative to the longitudinal axis of the envelope.

- the charge of concrete and / or insulating material is inserted in the area between the envelope and the hollow profile core.

the charge of concrete and / or of insulating material is introduced into the zone situated between the envelope and the hollow profile core and into the central zone of said hollow profile, the concrete and / or the material insulating from the two zones being able to be composition and different properties.

 The description which follows and the appended figures, presenting the nonlimiting exemplary embodiments, will make the invention better understood.

 Figure 1 shows an exemplary embodiment of the invention.

 Figures 2a and 2b show fixing means for ensuring a connection with at least one frame of the building.

 Figure 3 are two modes of construction of a pole according to the invention.

 Figures 4a and 4b show two other embodiments of the invention.

 It is known to use cylindrical sections of circular or quadrilateral cross section associated with floor supporting beams to form a metallic building structure.

 For example, the cylindrical profiles are mounted vertically, associated with each other, end to end, to form a column, the floor beams being fixed to the external wall of the profiles or also mounted passing through said profiles, the concrete being brought in for filling. profiles and formwork of the floor after mounting the structure. In this type of structure, the profile has only a formwork function. It then mechanically participates in the holding of the building as a metal frame for the column.

<Desc / Clms Page number 4>

 It is also known connection elements linking, during the assembly of the building structure, stacks with the floor beams. In this type of installation, the concrete load, intended to fill the piles to form the posts, is also brought to the site during the construction of the building.

 In the field of building construction, prefabricated elements are proposed, in particular posts, which are mounted on the site, which avoids construction by take-out and pouring of liquid concrete. Indeed, pouring of liquid concrete requires waiting a time for setting and obtaining its mechanical characteristics, time expressed in days.

 The post, according to the invention, is a prefabricated composite post for the construction of a vertical bearing structure of a building composed of at least one steel profile, cylindrical, hollow.

 The post 1, as shown in FIG. 1, is composed of at least one profiled steel casing 2, elongate, for example, cylindrical, comprising at one of its ends 3, a fixing means 4 for ensuring a connection with at least one building structure beam, and at the other end 5, a support and connection plate 6, all or part of the hollow profile being filled with concrete.

 According to the invention, the post comprises, an axial metal core 12, longitudinal and intended to ensure the bearing loads in the case where, by an effect of intense heating, the steel of the outer casing 2 lost these mechanical characteristics. Preferably, the core 12 is a hollow cylindrical profile.

 The fixing means 4, shown in FIGS. 2a and 2b, is made up of quadrilateral plates 7 joined by one of their sides 8 to form a star profile 9, the star profile 9 being able to bear at the end, a hollow polygonal plate 10.

 The fixing means 4 in part 3 of the post, in its star-shaped profiled part 9, consists of flat bars for example, welded at right angles, the profile forming a cross. The profile in the figures, in cross, aims to ensure a connection, for example, by bolting, at the level of the plates 7 with metal beams of the structure, placed horizontally, for example of type 1, or H .

 The plate 10 is a plate, for example, square, pierced in its center with a hole 11 of shape corresponding to the section of the section 2 elongated hollow. In this form, the star profile 9 is assembled to the envelope 2 coaxially, that is to say that the side 8 is placed in the longitudinal axis of the profile forming the envelope.

<Desc / Clms Page number 5>

 The plate 10, welded at the end of the cross section of the figure, is hollowed out to leave an opening for filling the concrete and / or thermal insulating material, in the internal space of the envelope 2. Its function is to ensure a preferably bolted connection through the floor, with the support plate 6 of the corresponding post of the upper floor of the building.

 The cross section, as shown in the figures, is mounted welded, at the end 3 of the casing 2 by fitting into four notches arranged longitudinally in the hollow section forming the casing. Although a hollow profile, associated with the fixing means 4 and the support plate 6, constitute the simplest form of the invention, the post preferably comprises a casing 2 and a core 12 made up of two cylindrical profiles concentric defining separate areas.

 The post is then constituted by an outer casing 2, hollow profile, of transverse dimension greater than the inner profiled core 12, to form an annular zone allowing correct filling of concrete or cement grout and / or insulator ensuring thermal insulation. of the core 12 so that it retains all its resistance up to the limit of the time imposed by the fire regulations.

 The outer casing 2 is the same length as the profiled core 12. The two sections are mounted coaxially or centrally by means of a centering device 13 as shown in Figures 3a and 3b. For example, the simple centering device consists of rods 14 passing through the core 12 and now radially and coaxially, in a spacer, the outer casing 2. The outer casing, centered, has notches corresponding to the plates 7 of the cross section. It is not necessarily welded.

 As shown in FIGS. 4a and 4b, the post preferably comprises two concentric hollow profiles generating two zones, one cylindrical, the other annular, one or both zones that can be loaded with concrete or cement and / or insulation.

 The envelope and the core, in the form of hollow sections, can be the subject of different possible combinations in the fields of their envisaged sections. To gain in performance, the profile of the internal core 12 can be made of steel with very high elastic limit. Such a composite post allows the transmission of significant bending moments even in the case of overheating resulting from a fire.

 The outer casing 2 and the core 12 participate, at ambient temperature, in the resumption of the weighted service load which the post must ensure. In terms of

<Desc / Clms Page number 6>

 sudden heating in the event of fire, the outer casing 2 loses its mechanical properties, and the profile of the inner core 12 then ensures, alone, the resumption of the load.

 It is recalled that the weighted load at room temperature is approximately 40% higher than the fire weighted load. The advantage of the post, according to the invention, lies in industrial manufacturing in the factory making it possible to provide building builders with ready-to-use structural components with a quality guarantee and generating cost savings, time, and substantial manpower.

 Two techniques for prefabrication of the composite post are to be considered depending on the type of insulation considered.

 A first exemplary embodiment consists in assembling the composite post, before filling, with an insulator. We therefore begin by making the fixing means by assembling the cross by welding metal plates and the associated plate. This plate is hollowed out to facilitate the installation of the filling material of the annular created zones and possibly the bolting of the central core. Then, the fixing means is introduced into the hollow profile of the core and welded. The part thus obtained is slipped into the external envelope on which the internal plate is welded. Finally, the annular zones are filled with insulation and the hollow core can be filled with concrete.

 A second embodiment consists, first, in assembling the profile of the core. We therefore begin by making the connection device by assembling the cross by welding metal plates and the associated plate. This plate can be full or hollowed out in the event of a bolting on the axial profile. Then, the fixing means is introduced into the hollow profile of the core and welded.

The insulator is then placed around the core thus obtained. The composite post is made by sliding the core-insulator assembly into the external envelope on which the plate is welded. The internal core can then be filled with concrete. The support plate, at the base of the post, can be full or hollowed out. Composite posts can be the subject of several possible combinations between the shapes of the external sections and those of the internal sections.

 According to the invention, the use of concentric hollow sections of steel section, for example polygonal and preferably square or rectangular, or circular, allow the assembly to participate in the recovery of service loads. In the event of a fire, the service charge is ensured by replacing the hollow profile

<Desc / Clms Page number 7>

 the inner soul. This differential recovery of forces is directly linked to the fixing means provided for assembling the beams of the structure to the post, fixing means which ensures a connection with at least one beam of the building structure, the profiled outer envelope and the plate. support also linking, mechanically, the core of the post.

 As shown, the internal space of the envelope is divided into zones partially or totally filled with concrete and / or insulating material. The filling of the annular zone, created between the profiled cylindrical envelope and the core, by means of a chosen material, delays the transmission of the temperature towards the interior core and possibly participates in the mechanical resistance. The possible filling of the internal area of the profiled core with concrete can contribute to the structural resistance and / or to the fire resistance of the composite post. As a result, the thermal transmission to the internal axial core is delayed thanks to the material, for example, insulating material placed in the zone situated between the envelope and the profiled core and, possibly, thanks to the increase in thermal inertia. due to the filling of the internal area of the core with concrete.

 The fixing means, to ensure a connection with at least one frame of the building, involves the external envelope and the core in the resumption of the service loads.

 In the event of a fire, above a certain temperature, the envelope no longer participates in the mechanical resistance of the composite post and, in this case, only the core, protected, insulated, and still at a relatively low temperature. , takes over the so-called fire service charges. In the case where the envelope forming the core is filled with concrete, it is the steel-concrete compound of the core which takes up the service loads and no longer the outer envelope of the post.

 The external envelope is a formwork which, depending on the heating in the event of a fire, loses all load-bearing function, but it does participate, in normal use, at room temperature, in the resumption of the weighted service load that must secure a composite post. The composite post and its fixing means, to ensure a connection with at least one frame of the building, ensure an adequate transmission of the forces of the beams of the structure to the post by a cross connection. On site, the connection between the reinforcement beams and the post is simple to make because the said connection is integrated into the post and only the beams are to be linked to the post. In other words, the post is prefabricated so that it does not

<Desc / Clms Page number 8>

 it is not necessary to associate in the assembly of the supporting structure, a joint or intermediate connection piece.

 The prefabrication of the post, according to the invention, opens up the possibility of taking advantage of the advantages offered by new steels with high mechanical characteristics.

The advantage of the composite post, according to the invention, lies in particular in industrial factory manufacturing, making it possible to make available to manufacturers, ready-to-use structural components with a guarantee of product quality and generating savings. cost, time and manpower. The post allows the service loads to be taken up in a differential and complementary manner. This differential recovery of forces is directly linked to the fixing means provided for assembling the structural beams with said post.

Claims (9)

 CLAIMS 1. Prefabricated composite post (1) for the construction of a vertical bearing structure of a building, composed of at least one steel section (2), cylindrical, hollow, characterized in that it comprises, an outer casing (2 ) cylindrical metal profile, an axial metal core (12), longitudinal, a fixing means (4) located at one of its ends (3) to ensure a connection with at least one beam of the building structure, a plate of support and connection (6) located at the other end (5), the internal space of the envelope (2) being divided by the core (12), into separate zones, each of the zones being partially or completely filled concrete and / or insulating material. 2. Post according to claim 1 characterized in that the cylindrical envelope (2) is of polygonal section, preferably square or rectangular, or circular. 3. Post according to claim 1 characterized in that the axial metallic core, (12) longitudinal, is a cylindrical hollow profile. 4. Pole according to claim 1 characterized in that the fixing means (4) with at least one beam of the building structure is composed of quadrilateral plates (7) joined by one of their side (8) to form a star profile (9). 5. Post according to claim 4 characterized in that the star profile (9) carries, at the end, a polygonal plate (10) hollowed out in its central part. 6. Post according to claim 5 characterized in that the plate (10) is a square plate, pierced in its center, with a hole (11) of shape corresponding to the section of the outer casing (2). 7. Post according to claim 4 characterized in that the fixing means (4), star profile (9), is a means of centering the metallic core (12) relative to

 the longitudinal axis of the envelope (2). i <Desc / Clms Page number 10>  8. Post according to claim 1 characterized in that the load of concrete and / or insulating material is inserted in the area between the envelope (2) and the hollow profile core (12). 9. Post according to claim 1 characterized in that the load of concrete and / or insulating material is introduced into the area between the envelope (2) and the hollow profile core (12) and in the central area of said profile hollow (12), the concrete and / or the material insulating the two zones which may be of different composition and properties.