WO2009010994A1

WO2009010994A1 - Self-supporting panel for building floors, and floor resulting therefrom

Info

Publication number: WO2009010994A1
Application number: PCT/IT2007/000505
Authority: WO
Inventors: Maurizio Morandi
Original assignee: Metecno S.P.A.
Priority date: 2007-07-16
Filing date: 2007-07-16
Publication date: 2009-01-22

Abstract

The invention relates to a panel (1) for floors of civil and industrial buildings or the like, wherein a central core (2) made of plastic expanded material is interposed between two outer faces (3, 4); the latter are preferably made of metal or plastic sheet or another appropriate material, and allow to provide the panel with good mechanical properties, thus eliminating the need of inserting metal sections therein acting as reinforcing structural elements.

Description

Description of Invention: "Self-supporting panel for building floors , and floor resulting therefrom"

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The present invention relates to a panel for the construction of floors of civil and industrial buildings or the like.

In the building sector, as an alternative to the traditional hollow bricks it is known that filler elements can be used, the main function of which is to fill up the floor and to provide thermal insulation; the concrete which is then cast on these elements carries out the structural function of bearing the loads applied to the floor.

Generally, said elements are blocks having substantially a parallelepiped shape, made of a plastic expanded material such as polystyrene or the like, which are laid side by side on the framework of the load-bearing beams of the building; the side- by-side blocks thus create a sort of formwork on which concrete can be cast in the usual manner.

Since expanded materials like polystyrene do not have good mechanical properties, it is customary to reinforce the floor filler blocks with metal sections buried therein; some examples of this type of construction are described in the published European patent application EP 459 924 and International patent application WO 2005/121467.

From a structural point of view, these solutions seem to be appropriate because suitably sizing metal sections, they allow to reinforce the filler blocks so that they can bear the weight of the concrete.

However, the presence of metal sections within the expanded mass represents a material discontinuity factor that adversely affects the structure of the filler element. In fact, the expanded material gets deformed differently from the metal sections under load, and thus it seems inevitable that these two materials will become detached from each other in the long run, so that the block will de facto no longer behave as one body. In order to try to limit this drawback, apertures are made in the sections in order to ■ allow the polymeric material to expand, so as to obtain mutual interaction between the two materials; however, since the sections extend from one face to the other of the expanded block, their deformation is very different between the intrados and the extrados of the block, so that it is very difficult to prevent the expanded material to become detached, even with apertures in the sections.

This is probably the reason why, in the above-mentioned International application WO 2005/ 121467, holes are made in the expanded material which allow the concrete to penetrate and reach the sections, so that the latter are made to interact and improve the carrying capacity of the floor; in fact, the purpose of this is to anchor the concrete to the sections as it cures.

It is however apparent that, also due to these holes, the expanded material is weakened even more, so that its structural contribution within the floor is further reduced.

It can thus be understood, from what summarized above, that the current state of the art has limits which should desirably be avoided: this is the object that the present invention aims at attaining.

Namely, it aims at providing a floor filler element having improved mechanical properties compared with expanded blocks reinforced with metal sections, the size and weight thereof being equal, thus allowing to build floors having higher carrying capacity. The idea at the basis of this object is to provide a filler element in the form of a composite panel, i.e. having a configuration wherein a core made of plastic expanded material is interposed between two laminar outer faces integral therewith; said faces are preferably made of sheet metal, whereas the core is made of expanded polyurethane.

Further features of the invention are set out in the claims appended to the present description; the invention also relates to a floor comprising a plurality of filler elements, the features of which are also set out in the appended claims. Such features, the effects deriving therefrom, and the advantages attained by the invention will become apparent in the light of a non-limiting preferred example of embodiment thereof, which will now be described with reference to the annexed drawings, wherein:

- Fig. 1 is a perspective view of a composite panel for floors according to the invention; - Fig. 2 is a cross-sectional view of the above composite panel;

- Fig. 3 is a cross-sectional view showing the arrangement of a number of panels according to the invention in a floor before concrete is cast;

- Fig. 4 is a cross-sectional view of a floor built by using panels according to the invention. In the drawings, a composite panel according to the invention is designated as a whole by reference number 1; it comprises an insulating core 2 preferably made of polyurethane-based synthetic foam, which is interposed between two outer faces 3 and 4 made of sheet-metal. In this example, the top face 3 has ribs 5, whereas the bottom face 4 is flat; however, the latter may have cavities for housing pipes, ducts, wirings, etc. Furthermore, in accordance with this preferred embodiment, the ribs 5 have upward-diverging sides 6, thus forming undercuts which will be described in detail later on.

At its base, the insulating core 2 has two edges 7, 8 protruding sideways and having complementary step-like profiles which overlap when the panels 1, 1', 1" are arranged side by side in the floor (see Figs. 2 and 3); advantageously, the ends of the sheet forming the bottom face 4 of the panel can be bent over these protruding edges 7, 8, thus securing said sheet firmly to the insulating core. From the protruding edges 7 and 8 of the panel, respective lower portions 9 and 10 of the sides of the insulating core 2 extend by diverging upwards as previously described for the sides 6 of the ribs 5; according to a preferred embodiment of the invention, the bent ends of the sheet 4 are juxtaposed to said lower portions 9 and 10. The remaining portions 1-1, 12 of the core sides are substantially vertical. From a dimensional point of view, it can be said that, in normal applications, the thickness S of the insulating core 2 in its central area, i.e. the area comprised between the side portions 9, 11 on one side and 10, 12 on the other side, may vary from about 10 to 30 cm; the base of the core 2, i.e. the layer adjoining the bottom face from which the edges 7 and 8 protrude, has a variable height H between 2 and 8 cm.

In general, it can be said that, in the floor panel according to the invention, the ratio S/H between the thickness S of the core and the height H of the base is between 2.5 and 8, preferably greater than 5. The panel 1 may be longer than 2 meters while still retaining its self-supporting property, i.e. it can be laid on a span of this length and carry loads without suffering any deformation beyond preset values; this is due to its composite structure, wherein the laminar faces 3 and 4 contribute to improving the mechanical properties of the expanded core 2 by cooperating with if as in similar panels used for other applications.

Within this context, it must be underlined that the ribs 5 being present on the top face 3 of the panel are projections a few millimeters high, generally 5-20 mm; they cannot therefore be compared to the frets of construction panels, manufactured by the same Applicant, which have a structural reinforcement function. Moreover, the panel 1 according to the invention may even have no ribs 5, resulting in the top face 3 being as flat as the bottom face 4.

For laying a floor in situ, the panels 1 are arranged side by side by overlapping their step-like edges 7 and 8 as shown in Fig. 3, which illustrates assembled panels 1, 1' and 1" (homologous elements of the panels 1 and 1" are designated with one or two apostrophes). The panels I, V, 1" are secured to the beams of the framework supporting the floor (not shown in the drawings) in a known manner, by using bolts, brackets or the like, or else by means of joints; advantageously, since the panels 1 may be longer than 2 meters, it will not be usually necessary to employ section breakers for spans exceeding said length. On the laid panels, between which reinforcing elements such as rods, latticework or the like may be inserted, concrete 15 is then cast; when the latter has taken shape, the above-mentioned usual finishings can be applied to the floor. The above description refers to laying a floor on site by using panels according to the invention; however, such a floor can also be obtained industrially as a pre-cast product, which is then laid on site as a simple construction element. In such a case, the composite panels 1, V, 1" are arranged in moulds within which concrete is then cast: when the concrete has taken shape, a pre-cast floor module will be obtained, which can subsequently be transported to the site for its installation. In both cases, i.e. whether the floor structure is laid on site or manufactured as a precast product, the properties obtained in terms of carrying capacity are very good.

In fact, the filler panels 1, 1', 1" have better mechanical, strength and flexional rigidity properties, in relation to their weight, than the simple polystyrene blocks reinforced with metal sections as described above.

This is due to the fact that the panels according to the invention are composite ones, i.e. instead of having a simple expanded core as used in the prior art, which needs to be reinforced internally with metal sections, they have real "sandwich" structures wherein the top face 3 and the bottom face 4 cooperate in synergy with the central core 2.

Also, said faces are panel components located at the greatest distance from the neutral axis, so that they provide the utmost effect on mass distribution for the moment of inertia of the resistant section. In other words, this means that the outer faces 3, 4 of the composite panel 1 can provide, with less weight, the same reinforcement effect as that provided by metal sections incorporated in expanded material as described in the above-mentioned European patent application EP 459 924 and International patent application WO 2005/121467. In addition, diverging surfaces 6 may be provided in the ribs 5 on the laminar top face 3, thus promoting cooperation between the panel 1 and the concrete as the latter shrinks due to hardening. It can be easily understood, in fact, that the undercut produced by said diverging surfaces acts as an anchorage point for the concrete, which while shrinking exerts an upward pulling action on the panel, thus compensating for the deformation of the latter caused by the mass of concrete. In this frame, it should be noted that the lamina forming the top face 3 (whether made of sheet metal or any other appropriate material) prevents the expanded material of the core 2 from suffering any damage caused by tension induced by the concrete on the diverging surfaces 6. The same concrete anchoring effect is also provided by the lower side portions 9 and 10 of the insulating core 2, to which the lamina of the bottom face 4 is juxtaposed; consequently, in this embodiment of the invention, the interaction between the concrete and the panels occurs both on the top face 3 and along the sides thereof, thus improving the overall behaviour of the floor. The above description has clearly explained how the panels according to the invention achieve the expected object.

As a matter of fact, they carry out the same functions as analogous polystyrene blocks known from European patent application EP 459 924 and International patent application WO 2005/ 121467, without however suffering from any drawbacks due to the presence of reinforcing sections within the expanded material.

Thus, for example, the composite panels 1, V, 1" laid in the floor act as a framework for the concrete casting, while at the same time facilitating the work since they are self-supporting and people can therefore walk on them; furthermore, the panels 1, 1', 1" can be easily moved because they are not heavy; also, they can be coupled to one another very quickly, by virtue of the protruding edges 7 and 8. The composite panels according to the invention have also very good thermoinsulating properties, due to the core 2 being made of synthetic polyurethane foam.

However, as mentioned, unlike prior-art floor blocks, the composite panels 1 according to the present invention do not need any internal reinforcing sections. It follows that they are not affected by any problems due to the sections becoming detached from the expanded material, which typically weaken the structure of known floor elements. This achievement derives from the particular configuration wherein the expanded core is interposed between the two outer faces 3 and 4 which, as described, cooperate therewith to improve the mechanical properties of the panel. A further advantage of the composite panel 1 according to the invention is that it may be manufactured through a continuous in-line process, just like the insulating panels manufactured by the present Applicant; in this case, it is therefore advantageous that the outer faces 3, 4 are made of sheet-metal, since this material can be fed continuously from a coil. Nevertheless, other materials may also be used as mentioned below.

In this frame, it is however necessary to point out that the composite configuration of the floor panels according to the invention also allows to use different materials for the insulating core.

Thus, for example, it will be possible to manufacture floor panels wherein, in addition to polyurethane-based foam or the like, the insulating core also includes a . layer of mineral wool: in fact, the two outer faces 2 and 3 allow to keep these heterogeneous materials together sandwich-wise, providing a multi-layer composite panel as a result. By the way, it must be pointed out that mineral wool improves the fire-resistance property of the panels.

Of course, the invention may be subject to many variations with respect to the description provided so far. As already mentioned, the outer faces 3, 4 of the panel 1 are preferably made of sheet-metal; this solution combines the possibility of profiling the sheet during a continuous in-line production process with the possibility of ensuring good performance in terms of mechanical properties of the finished panel. Alternative solutions may nonetheless be taken into account depending on different requirements; thus, for example, the outer faces may also be obtained from sheets made of a plastic material, such as polycarbonate, PVC, polyethylene, fiberglass (fiberglass reinforced plastic), or other laminar materials like laminated wood or the like. Variations are also possible as regards the shape of the panels; for example, the lamina (sheet metal or another material) of the top face 3 may also extend along the sides 11, 12 of the insulating core 2, as may do the lamina of the bottom face 4: in the example shown in the drawings, the latter ends at the diverging surfaces 9 and 10 of the panel sides, but it may even extend past said surfaces. Also, said sides may be protected by strips or films made of an elastomeric material (rubber or the like), similar to a gasket.

The diverging surfaces may also be conceived as having profiles other than the above-described inclined undercut surface; thus, for example, curved or square profiles may be employed, provided that they are adapted to promote the ^" interaction between the concrete and the panel as explained above. It is even conceivable that the upper side portions 11 and 12 of the insulating core 2 are inclined like the lower portions 9 and 10, thus configuring the cross-section of the core 2 as a single dovetail with which the concrete 15 cooperates in accordance with the same principle set out above.

A further possible variation of the floor according the invention from the above- described example consists in providing channels or seats in the insulating core 2 for laying cables, pipes or the like.

Said channels are similar to those used in known floor elements,¹ and can be obtained by applying sheaths, pipes or the like during the production process, which are then incorporated into the polymeric insulating matrix as the liquid base resin expands. Finally, a further possible variant of the panel according to the invention may be obtained by having only one edge 7 or 8 protrude from the base of the insulating core 2; for this purpose, it is sufficient that the edge is as large as both edges (7 and 8) of the preceding example, so that when the panels 1, 1', 1" are laid, the respective insulating cores 2 will turn out to be spaced by a distance D as shown in Figs. 3 and 4.

To this end, it is in fact necessary to remember that the space between the insulating cores 2, 2', 2" of the panels is used for casting the joists^of the floor, i.e. those parts of the structure which have carrying functions. In the single-edge variant of the panel, a seat may be provided in that portion of the core abutting against said single edge when the panels are laid, in order to allow adjacent panels to be coupled together in much the same way as the step- like profiles of the edges 7 and 8. All of these variants still fall within the scope of the following claims.

Claims

1. Panel for floors of civil and industrial buildings or the like, comprising a core (2) made of insulating material, characterized in that said core is interposed between a top face (3) and a bottom face (4), with reference to the laid condition, which are laminar or substantially flat, and that the insulating core (2) comprises at least one protruding edge (7, 8) near the bottom face (4), so that in the laid condition the insulating core (2) is located at a predetermined distance (D) from that of an adjacent panel.

2. Panel according to claim 1, wherein at least a portion (9, 10) of the sides (11) of the insulating core (2) has a substantially diverging shape extending from the bottom face (4) to the top face (3).

3. Panel according to claims 1 or 2, wherein the laminar bottom face (4) has ends bent onto the edges (7, 8) of the insulating core (2).

4. Panel according to claim 3, wherein the bent ends of the bottom face (4) extend along the diverging portion (9, 10) of the sides of the insulating core (2).

5. Panel according to any of the preceding claims, comprising edges (7, 8) protruding from respective opposite sides of the core (2) which are complementary to homologous edges (7', 8'; 7", 8") of other adjacent homologous panels (1', 1") in the floor.

6. Panel according to claim 5, wherein the edges (7, 8) have a step-like profile.

7. Panel according to any of the preceding claims, wherein the top (3) and bottom (4) faces are made of sheet-metal.

8. Panel according to any of the preceding claims, wherein the top face (3) has ribs (5).

9. Panel according to claim 8, wherein the ribs (5) have upward-diverging sides (6), thus forming undercuts.

10. Panel according to any of the preceding claims, wherein the insulating core (2) comprises a layer of plastic expanded material.

11. Panel according to claim 10, wherein the plastic expanded material is of the polyurethane type.

12. Panel according to claim 10 or 11, wherein the insulating core comprises a layer of mineral wool.

13. Panel according to any of the preceding claims, wherein the insulating core (2) comprises a central area delimited laterally by respective sides (9, 11; 10, 12), the ratio between the thickness (S) of said central area and the height (H) of the core base from which the edges (7, 8) protrude being comprised between 2.5 and 8.

14. Panel according to claim 13, wherein the ratio between the thickness (S) of the central area of the insulating core (2) and the height (H) of the base is greater than 5.

15. Panel according to any of the preceding claims, wherein the top face (3) extends partially along the sides (9, 11; 10, 12) of the insulating core (2).

16. Floor structure for civil and industrial buildings or the like, characterized by comprising a plurality of panels (1, 1% 1") in accordance with claims 1 to 15.