In particular, the invention relates to a floor beam, girder or the like for making floors in combination with beams of foam construction material.

Furthermore the invention relates to an element made of light material associated to a self-supporting element for spanning floors.

Background of the invention The need is felt to provide floors that are resistant and at the same time light, for bearing the least possible on the structures.

It is well known, for example, the use of beams of foam construction material, for example structural elements known with the trade name PLASTBAUO for making floors, alternatively to the traditional floors.

Such beams are of elongated shape, obtained for extrusion normally of foam polystyrene. In many cases they are reinforced with metal and/or concrete elements. After installing the beams it is possible directly to install the reinforcement and to carry out the concrete casting of the floor.

The advantages of floors made with these beams are many, among which: - the installation is easier since they are self- supporting elements and do not require scaffolding and wood stages; - lighter elements with respect to the heavy elements in tiles and concrete, such as concrete beams or girders in reinforced concrete, hollow tiles etc., may be handled;

- a high heat insulation is obtained along with a good resistance given by the foam construction material; - the floor is considerably lighter, thus being advantageous the use of these beams especially in the redevelopment of old buildings whose structures do not allow heavy loads; - they have a long duration.

In a type of boards, in particular, a longitudinal central recess is made oriented in use towards below, wherein a floor beam in reinforced concrete is housed, for allowing the beam to be self-supporting during the installation of the floor. The floor beam can be directly cast in the recess, or it can be made separately and mounted during the installation.

A drawback of this floor beam is its weight, which even if in a small part, affects the advantages of minor weights that are obtained with the use of these boards.

Another drawback is that these concrete beams cannot be drilled easily from below for application, for example, of plaster suspended ceilings, wood boards and similar.

Alternatively to the boards of polystyrene foam, like those called PLASTBAUO, other light elements are available, for spanning floors before the concrete casting. These elements normally must be self supporting and easy to be laid.

Another relevant aspect, is the possibility of finishing the ceilings under the floors with plaster suspended ceilings. In fact, the plaster suspended ceilings require metal brackets to which they are connected by means of self-tapping screws. The metal brackets are in turn connected to the floors by means of expansion bolts. In particular, is difficult to pierce girders or other structural elements, usually in reinforced concrete. Furthermore metal brackets for supporting plaster suspended ceilings are laborious to arrange.

Summary of the invention It is object of the present invention to provide a light element for spanning floors, that is self-supporting and that has not the drawbacks of the known art.

It is a particular object of the present invention to provide a self-supporting floor beam or the like that makes remarkably easier the installation of a floor associated to beams of foam construction material and is lighter than the existing concrete beams.

It is a further object of the invention to provide a self-supporting floor beam that allows the fastening of plaster suspended ceilings directly to the lower surface of the floor beam same.

According to a first aspect of the invention, a structural element has the characteristic that it comprises a hollow metal section filled inside with foam construction material.

Preferably, the structural element according to the invention is formed by two beam sections coupled to each other in order to define an inner volume that is then filled with the foam construction material.

The foam construction material can be chosen among cellular polyurethane, foam polystyrene, etc.

In particular, the self-supporting floor beam according to the invention can comprise a first metal section, substantially flat with folded side edges, and a second metal section formed by two wings that extend from a longitudinal axis and which, starting from a rest position, are approached elastically up to reaching the shape of the recess of the beam. The two metal sections are then combined so that the edges of the wings of the second metal section resiliently force in the folded edges of the first metal section. This way the resulting floor beam has substantially a"T"cross section. Then, it is

filled with foam construction material, preferably cellular polyurethane.

In particular, the addition of the foam construction material, in particular cellular polyurethane, causes the side surfaces of the second metal section to force against the first section, so that the floor beam is substantially steady and self-supporting.

The first metal section of the floor beam is oriented in use towards below and allows thus for example the easy application of self tapping screws for fastening plaster suspended ceilings. In fact, the screws penetrate the first lower face of the metal section and penetrate the foam construction material.

The self-supporting element according to the invention can replace the floor beam of concrete traditionally used in combination with the beams of the type PLASTBAU@.

In a first embodiment of the method according to the invention, the step of installation of the concrete beams is rather simple: an end of said floor beam is laid on an edge of the foundation or of a boundary wall to which it has to be previously fixed. Furthermore since the floor beam according to the invention can be perforated by the screws, it is possible screw it directly to principal steel structures of the building, such as for example to steel beams, or it can be connected by means of epoxy resins.

To the floor beams the PLASTBAUO elements are associated and possibly metal nets are laid to reinforce the floor. Then concrete is cast thus forming the casting of the floor.

The advantages in the use of the self-supporting

element according to the invention are many: - such a floor beam associated to the light foam construction material makes floors lighter than those traditionally made, but substantially with the same resistance; - the floor beam is light also when handled and it can be carried by hands; - the foam construction material combined with the floor beam according to the invention allow to obtain self- supporting elements stiff enough and capable of supporting the operations of installation of the floor without the use of wood stages; - a floor made in this way can be coated from below with plaster boards connected with screws directly on the lower metal sections of the beams self supporting beams.

- The savings for application of the plaster board relate to both minor laying time and less operative work; - better acoustic and heat insulation.

According to another aspect of the invention, a structural element has the characteristic that it comprises a stiff continuous plastics shell with concavity towards below, suitable for spanning floors.

Advantageously, the structural element is associated to a stiff continuous beam that is connected centrally at its concave side, in longitudinal direction.

The structural element, can be used for spanning floors before the concrete casting, and can either rest on the longitudinal sides of girders, as well as can be completely self-supporting without resting on the girders.

Advantageously, the structural element has stiffening ribs extending towards below.

According to a further aspect of the invention, a structural element has the characteristic that it comprises a continuous foam stiff spanning element.

Brief description of the drawings Further characteristics of the self-supporting element for making floors in combination with beams of foam construction material according to the present invention will be made clearer with the following description of an embodiment thereof, exemplifying but not limitative, with reference to the attached drawings, wherein: - figures 1A and 1B show respectively a cross sectional view and a perspective partially cross sectioned view two hollow tiles next to each other combined to self- supporting beam elements to which plaster suspended ceilings are connected; - figure 2 shows a cross sectional view of a beam of foam construction material associated to the structural self- supporting element according to the invention; - figure 3 shows two metal sections that form the floor beam according to the invention, coupled to each other with inside a casting of foam construction material; - figures 4A, 4B and 4C show the steps of assembling two metal sections for making the structural self-supporting element of figure 3; - figures 5A, 5B and 5C show respectively in side, front and top plan view a self-supporting floor beam according to the invention combined to a beam of foam construction material and connected by means of screws to a structural element, such as for example a beam of steel; - figures from 6 to 13 show various views of an embodiment of a self-supporting element according to the invention; - figures 14 and 15 show a further embodiment of the self-supporting element according to the invention for casting floors.

Description of a preferred embodiment

Figures 1A and 1B show diagrammatically a cross sectional view of a floor 1 made with a structural element or floor beam 2 according to the invention associated to extruded beams 3 of foam construction material for example of the type PLASTBAU@. In figure 2 the beam 3 is shown resting on a floor beam 2, which is formed by a hollow metal section filled with foam construction material 10.

More precisely, with reference to figure 3, the floor beam 2 consists in two sections 4 and 5, coupled to each other, in order to define inside a hollow space 9 (figure 4C) filled with foam construction material 10, which can be chosen among cellular polyurethane, foam polystyrene, etc.

The first metal section 4 is substantially flat with side edges 8 folded towards the inner, in order to form a hook; second metal section 5 is formed by two wings 6 that extend from a line longitudinal fold 5a which, starting from a rest position (figure 4A), are approached elastically (figure 4B) to each other for reaching the shape of recess 3a of beam 3 of figure 2, substantially with T cross section. Two metal sections 4 and 5 are then combined (figure 4C) so that the edges 7 of the wings 6 of the second metal section 5 force against the folded edges 8 of the first metal section 4. In particular, second metal section 5 reacts elastically whereby it can be put in the first metal section 4 easily and quickly.

The union of the two metal sections 4 and 5 defines its inner hollow volume 9 (figure 4C) that is filled with foam construction material 10 (figure 3). This way, the addition of the foam construction material 10 causes the edges 7 of wings 6 of second metal section 5 to force

against the side folded edges of the first metal section 4, so that floor beam 2 is substantially stiff and steady.

Edges 7 and 8 are shaped in order to provide a steady hooking that becomes steadier when the resilient action of wings 6 and expansion forces of the foam construction material 10 add to each other.

The beams 3 combined with floor beam 2 according to the invention provides self-supporting elements light and strong that can support heavy loads, so that the floor thus obtained is capable of supporting the operations of installation of the floor same without the use of wood stages.

More precisely, the step of installation of floor beams 2 according to the invention provides the following steps: - firstly, it is necessary to lay, either on a groundwork, or on boundary walls or on structural beams, the end of beam 2; in the case of steel beams 12, for example T or H shaped, since metal section 4 can be perforated by screws 15, it is possible to fix the floor beam 2 in a steady way to beam 12 (see figure 5A, 5B and 5C); - Immediately after, to concrete beams 2 thus laid beams 3 are associated that form the basis for casting the floor; in fact, as above said, floor beam 2 is such that its external shape fits with the recess of beam 3 (see figure 2), whereby their combination forms a single and compact body; screw anchors 14 for fastening floor beam 2 to hollow tile 3 may be used; - then, the reinforcement of the floor, not shown, is carried out and then the concrete casting 13 (figure 1A and 1B) ;

- finally plaster suspended ceilings 40 (figure 1A and 1B) may be attached from below; this step is easy and quick, since it is possible (figure 2) to use self tapping screws 11 that cross metal section 4 and penetrate the foam construction material 10.

The possibility of applying plaster suspended ceilings 40 to the lower surface of the floor connected with screws 11 is particularly advantageous, since the traditional beams in reinforced concrete cannot be drilled or screwed.

The savings are not only related to a quicker installation but also to less operative work, with a subsequent reductions of the costs of construction.

With reference to figures from 6 to 13, a structural element 21 according to an embodiment of the invention has the characteristic that it comprises a shell 23 of continuous plastic stiff material with concavity towards below, suitable for spanning floors.

Advantageously, the structural element is associated to a stiff continuous beam 22 that is connected centrally at its concave side, in longitudinal direction. This beam, at its lower edge, may be connected to a metal section that can be perforated 24 for application of plaster suspended ceilings.

The structural element, can be used for spanning floors before the concrete casting, and can either rest on the longitudinal sides of girders 20 (figure 7), as well as can be completely self-supporting without resting on the girders (figure 9).

Advantageously, the structural element 21 has stiffening ribs 28 extending towards below (fig. 10 and 11), and provides covering plugs 27 at the ends (fig. 12) as well as abutting anchorages 30 (fig. 13).

According to a further aspect of the invention, a structural element 41 has the characteristic that it

comprises a continuous foam stiff spanning element (figures 14 and 15).

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.