DESCRIPTION
FIELD OF THE INVENTION
The present invention refers to prefabricated elements made
of insulating materials to be used in the construction of
floors, and in particular to a modular element made of sintered
expanded-polystyrene for building reinforced-concrete' floors.
The invention also relates to a reinforced-concrete floor built
by using a plurality of said modular elements, arranged one adjacent
to the other, which remain integrated in the floor.
STATE OF THE PRIOR ART
The technique of building floors made of reinforced concrete
using, for preparing the provisional casting plane, ele-
1 ments made of expanded plastic materials, preferably sintered
expanded-polystyrene, instead of the traditional brick elements,
has been known for a long time in the building industry.
The floor building technique is substantially identical in
both cases and provides to form said casting plane through a
plurality of self-supporting elements arranged side by side,
preferably with overlap or mutual joints, and resting at their
ends against perimeter walls or pillars. Before accomplishing
the casting, between pairs of adjacent elements made of expanded
polystyrene, and in correspondence of a longitudinal channel
formed in the same, reinforcing rods are arranged in a fully
conventional manner, so that, once the casting has occurred, the
floor embeds within itself both the expanded-polystyrene elements
and the reinforcing rods. In correspondence of the reinforcing
rods, longitudinal joists are hence formed, which provide
the mechanical strenght of the floor once the concrete has
hardened. With respect to the floors formed with brick elements,
the floor with expanded-polystyrene elements has - the mechanical
strenght being the same - a remarkably smaller weight and a
much greater thermal insulation coefficient.
WO-A-98/16703 is a representative document of the technique
illustrated above which discloses a prefabricated element made
of polystyrene wherein two Z-shaped longitudinal metal sections
are embedded, upon fabrication of said elements, which metal
sections provide a self-support feature thereto. The lower sides
of the L-shaped sections are in view and resting on the lower
face of the prefabricated element, so that they may be used to
fasten a metal reinforcing mesh thereto by welding. Such mesh is
5 meant to ease the anchoring of a lower covering such as plaster
and to guarantee the overall mechanical solidity of the construction
even in case of fire, in which situation the expandedpolystyrene
material might melt due to the high temperatures.
PROBLEM AND SOLUTION
10 The problem at the basis of the invention is to provide a
prefabricated polystyrene element of the type illustrated above
which allows, in addition to the reinforced-concrete longitudinal
joists described above, also building crosswise joists, so
that the mechanical strenght of the floor is identical in the
15 two directions forming a so-called plate floor with remarkably
better performances.
In fact the same problem has already been addressed in the
known art, as shall be seen in the following, however, with solutions
far from being satisfactory both due to the construction
20 complications which suc solutions entail and due to the insufficient
level of prefabrication which still requires a high degree
of skilled labour during laying.
WO-A-2005/121467 has a structure fully similar to the one
described above for WO-A-98/16703, of which it recalls all the
25 essential elements. However, the metal sections which make the
polystyrene element self-supporting have an L shape, wherein the
upper end of the section is folded on itself, hence causing a
slight thickening thereof. In a first embodiment the element is
conceptually identical to the one described above and it hence
30 allows building floors only provided with reinforced-concrete
joists having a longitudinal direction. In a second embodiment,
the metal sections are not provided during the manufacturing
process of the polystyrene elements, but are inserted later,
into respective seats formed in the polystyrene through a me-
35 chanical cutting process (for example by hot thread) of the element.
This separate-steps fabrication method hence allows to
form also a series of crosswise grooves in .the polystyrene element
into which reinforcing rods may then be arranged to thus
finally obtain a plate floor having reinforced-concrete joists
oriented in two perpendicular directions.
However, the solution proposed in WO-A-2005/121467, in addition
to the evident complication and to the greater costs of
the two-steps manufacturing, also has two remarkable technical
disadvantages. A first disadvantage is due to the fact that the
metal sections are no longer securely anchored to the expanded
material - as occurs instead in the simultaneous manufacturing
process in which said material penetrates, in the fluid state,
in the holes existing on the wings of said sections - but are
simply inserted in the same. That close connection between sections
and expanded material is hence lacking, which connection
being the only feature apt tp cause an even and correct distribution
of the mutual loads both during the transport and laying
operations and during the floor-building step. A second remarkable
operational disadvantage is furthermore connected to the
fact that the operation of laying the reinforcing rods in the
crosswise channels may of course be accomplished only after the
metal sections have been positioned, thus creating a plurality
of barriers within said channels. It is hence not possible to
arrange the rods in said channels from above, according to the
standard building site procedure, but the rods must instead be
inserted laterally introducing them one by one into the holes
provided on the wings of the different metal sections which interrupt
the continuity of said channels. Hence an operation
which is not always possible to be performed, due to the evident
need for a free space next to the floor under construction having
a size at least corresponding to that of the floor itself,
and in any case an extremely long, difficult and labourintensive
operation.
WO-A-2006/040624 addresses the same problem, however, offering
a solution of a different type, in which the polystyrene
elements are divided into two separate layers which are mounted
only during the installation on-site. A first base layer forms a
low-thickness continuous plane and embeds the metal sections
which provide a self -support feature thereto. A second layer
consists instead of individual parallelepiped elements which are
positioned one-by-one according to a grid-like pattern on the
base layer, forcedly inserting them on a portion of the metal
sections protruding from the base layer, so as to leave between
them both longitudinal channels and crosswise channels in which
the reinforcing rods are then arranged. Although this solution
removes the drawback shown above in connection with patent WO-A-
2005/121467, i.e. the lateral insertion of the reinforcing rods,
it still has instead the drawback of an insufficient anchoring
of the upper polystyrene layer to the metal sections and of a
remarkable installation complexity of such layer, the individual
parallelepiped elements of which must be accurately positioned
15 in a longitudinal direction, possibly using suitable templates,
to guarantee that the crosswise channels formed thereby have
constant width and perfect alignment.
The object of the present invention is hence that of providing
a prefabricated polystyrene element of the self-
20 supporting type which solves the above-described problem of allowing
building a plate floor comprising reinforced-concrete
joists in two orthogonal directions, however, without being af -
fected by the above-described drawbacks of the prior art.
In particular it is hence a first object of the present in-
25 vention to provide, a prefabricated polystyrene element of the
type described above in which the reinforcing metal sections are
perfectly embedded in the expanded material during the prefabrication
procedure.
A second object of the present invention 'is to provide a
30 prefabricated polystyrene element of the type described above,
already perfectly complete and available in modules extending in
a longitudinal direction at a desired length, so that such element
may be directly installed side by side to other similar
elements, without requiring any other further mounting or fin-
35 ishing operation or insertion of additional bodies, despite allowing
the desired creation of said crosswise channel's.
Such objects are achieved through a modular expandedpolystyrene
element having the features defined in the main
claim herewith enclosed. The dependent claims describe other
preferred features of the invention.
5 BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the invention will in
any case be more evident from the following detailed description
of a preferred embodiment thereof, given purely as a nonlimiting
example and illustrated in the attached drawings,
10 wherein :
fig. 1 is a schematic perspective view of a modular polystyrene
element according to the present invention:
fig. 2 is a crosswise section view in an enlarged scale of
the modular element of fig. 1; and
15 fig. 3 is a schematic perspective view of a plurality of
modular elements laid side by side to provide a casting plane
for the construction of a floor.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
As clearly illustrated in figs. 1 and 2, each modular ele-
20 ment E of the present invention consists of a single sintered,
expanded-polystyrene body, within which two metal sections A are
embedded which impart a self-support feature to the element, in
a fully similar way to the reference known art consisting of
above-described patent WO-A-98/16703, the full contents of which
25 are here considered included by reference. In particular the
polystyrene body has any length and a substantially rectangular
section from which lateral wings 4 project below, said wings 4
having a reduced thickness compared to the one of the main inner
portion 1 of said body.
30 The modular element of the present invention, however, is
characterised - compared to the prior art - by the fact that
metal sections A have an Q-shaped section, preferably comprising
edge-connected planar sides, as well as by the fact that the
overall height h of such sections is substantially equal to, or
35 slightly greater than, the thickness of the wings 4 of element
E. Due to this particular construction it is possible to provide
within each element E a series of crosswise recesses 2 being so
depth as to extend up to the upper part of the metal sections A.
Recesses 2 can thus have a fully equivalent size, both in width
and in depth, to the longitudinal cavities 3 which are formed in
5 the junction area between two adjacent elements E, according to
the teachings of the prior art, said recesses 2 and cavities 3
thereby defining the inner portions 1 of modular element E which
have a square or rectangular shape depending on whether the
pitch of recesses 2 is equal to or different from the width of
10 portions 1:
When multiple elements E are arranged one adjacent to the
other, a network of orthogonal channels 2 or 3 is thus formed,
within which it is easy and immediate to arrange, from above,
reinforcing rods F while, where desirable, a metal reinforcement
15 mesh R may simply be rested above the inner portions 1 of elements
E. At this point a concrete cast C, above the casting
plane consisting of elements E positioned side by side, builds
the desired plate floor provided with reinforced-concrete joists
both in a longitudinal direction and in a crosswise direction,
20 thus reaching the object of the invention.
As stated above, metal sections A have an Q-shaped section,
to be precise consisting of five edge-connected planar sides.
The two terminal sides and the central one of the section are
parallel to the lower face of element E while the two intermedi-
25 ate sides are perpendicular or moderately inclined with respect
to such face. Moreover, one of said terminal sides is positioned
adjacent to and outside the expanded-polystyrene body, so as to
be able to be used for the anchoring of a metal reinforcing
mesh, in a manner known per se, while the other terminal side is
30 embedded in the expanded-polystyrene body.
As will be clear from the preceding description, the modular,
lar, e~~anded-~ol~st~erleemnenet E of the present invention has
fully achieved the set objects. As a matter of fact it is an
element which is completely prefabricated in all its details in
35 the desired length and which may hence be installed in a fast
and easily automatable way. In such element El the metal sections
A which provide the self-support feature thereof are entirely
embedded in the expanded-polystyrene body and hence perfectly
integral with the same. The arrangement of multiple adjacent
elements E hence allows to obtain - with no further opera-
5 tions but the simple laying, from above, of reinforcing rods F
in a conventional manner - a casting plane already prepared with
orthogonal channels for building a plate floor with bidirectional
reinforced joists.
However, it is understood that the invention must not be
10 considered limited to the particular arrangement illustrated
above, which represents only an exemplifying emb~diment thereof,
but that a number of variants are possible, all within the reach
of a person skilled in the field, without departing from the
scope of protection of the invention, which is defined by the
15 attached claims.
We CLAIM:
1) Modular, sintered, expanded-polystyrene element for
building reinforced-concrete floors, of the type comprising a
polystyrene body within which metal sections (A) are embedded
which impart a self-support feature to said element, and wherein
said polystyrene body has any length and a substantially rectangular
section from the bottom portion of which lateral, lowthickness
wings (4) project, characterised in that said metal
sections (A) have an overall height (h) equal to or slightly
above the height of said lateral wings (4) and in that one or
more recesses (2) are furthermore provided in said polystyrene
body in a crosswise direction with respect to the one of said
metal sections (A).
2) Modular, sintered, expanded-polystyrene element as
claimed in claim 1, wherein said metal sections (A) have an Rshaped
section with edge-connected planar sides .
3) Modular, sintered, expanded-polystyrene element as
claimed in claim 1 or 2, wherein said crosswise recesses (2)
have substantially the same size of the cavities (3) which are
formed, above said lateral wings (4), in correspondence of the
junction area of two adjacent elements (E) .
4) Modular, sintered, expanded-polystyrene element as
claimed in claim 3, wherein said crosswise recesses (2) have a
direction perpendicular to said metal sections (A).
5) Modular, sintered, expanded-polystyrene element as
claimed in claim 4, wherein the distance between two adjacent,
crosswise recesses (2) is equal to the width of the inner portions
(1) of said elements (E) .
6) Modular, sintered, expanded-polystyrene element as
claimed in anyone of the preceding claims, wherein said metal
sections (A) having an Q-shaped section with edge-connected planar
sides have the two terminal sides parallel to the bottom
surface of said element (E), said sides being positioned, adjacent
to and outside and inside, respectively, the expandedpolystyrene
body.
7) Reinforced-concrete floor comprising: a casting plane
consisting of a plurality of modular, expanded-polystyrene ele-
I ments as claimed in any one of claims 1 to 6, arranged mutually 1 adjacent; reinforcing rods (F) arranged within said longitudinal
recesses (3) and said crosswise recesses (2) ; and, possibly, re-
5 inforcing meshes (R) arranged above the inner portions (1) of
I
the polystyrene body of said elements (E).