[0001] The present invention concerns a laid monolithic ceiling out of cement reinforced
concrete and the relative process for realizing the same.
[0002] In particular, the present invention concerns a ceiling particularly suitable for
the realization of structures for plane or not plane covers, out of conventional reinforced
concrete and postcompressed reinforced concrete, for building works in civil, military
and industrial fields.
[0003] At present, the most widespread technique for realizing the cover of great spaces
for industrial sheds, civil buildings, public works, military works, mainly consists
in the prefabricated cover that may be realized in different ways: like covers with
precompressed reinforced concrete beams, with an Y-shaped section, or with big precompressed
reinforced concrete tiles, or with the less used solution of gable beams out of precompressed
reinforced concrete. Further solutions may consist of a metal structure, laminate
wood, tensostructures or however other techniques or materials that allow the increase
of the free cover spaces and consequently greater free exploited and at disposal surfaces.
A great space usually means the space between the resting points of the ceiling that
varies betwee 15 and 40 meters. Above mentioned realizatio techniques have one common
feature, i.e. the fact that most of the structural elements are prefabricated in places
different from the building yard, like e.g. prefabricated elements out of precompressed
reinforced concrete and metallic shapes etc. Such prefabricated elements determine
an increase in the realization costs, due to the particular transportation manner
requested for the transfer to the building yard with consequent problems for the use
of the roads. The moving of said elements in the building yard requires the use of
extraordinary lifting means, such that make the safety of the building yards precarious
or however difficult. But there are also other lack that characterize said technologies.
The cover of great spaces with the precompressed reinforced concrete technique, completed
with light element with the criterium of simple supports, does not form a monolithis
realization that may guarantee in time the absolutly static nature of said structure.
The dynamic actions caused by the wind, by the natural and artificial thermal expansion
due to fire, natural catastrophies, great snowfalls or seismis movements, determine
the arising of safety problems for the structure and for the workers that are working
inside the building, due to possible falls of secondary structural elements. Furthermore,
the insulation is not easy to be realized as it is applied without continuity, leaving
some areas uncovered and thus creating thermal gaps and thus great heat dispersion
or thermic ranges.
[0004] It is the aim of the present invention to eliminate above mentioned inconveniences.
[0005] A particular care has been deserved to the quality of the product and to a low cost
production. Infact great amounts of building work productions are requeste in Italy
and in Europe, and furthermore the client has become still more demanding in the request
of the finished product.
[0006] The aims set forth are reached by means of the object of the present invention which
consists of a laid monolithic ceiling out of cement reinforced concrete, characterized
in that it comprises extrados beams which cooperate as a monolyth with a slab laid
during realization.
[0007] Extrados beams are beams with any shape and section, placed at suitable distances
according to the structural calculations, and realized out of materials fit for resisting
to load actions; they are made monolithis with the slab by means of a cement cast
and at least one portion of the square section is projecting with respect to the extrados
of said slab.
[0008] For realization needs and economy the extrados beams may be out of cement reinforced
concrete with a slow or postcompressed reinforcing; with reticular iron beams or with
other materials that may solidarize with the cover slab by means of a cement cast.
[0009] The realization process for obtaining the laid monolithic ceiling out of cement reinforced
concrete, comprising a slab and extrados beams, is characterized in that it comprises
the following phases:
- the building of at least two carrying pillars;
- the realization of an intrados formwork supported by props;
- the formation of the iron reinforcing of the slab and of the extrados beams;
- the filling of the formworks with cement for the cast of the slab and of the portion
of the extrados beams inserted into said slab;
- the realization of the formwork projecting from the extrados of the slab for the finishing
cast of the extrados beams.
[0010] In the case of lightened ceilings, the realization phase of the slab consists in
a first cement cast inglobing the lower reinforcing iron, the laying of the perforated
blocks out of polystyrene and of the upper reinforcing iron, the completing cement
cast of the slab up to the extrados. The full ceilings as well as the lightened ones
are furthe protected with a waterproofing coating of known kind.
[0011] Many advantages derive from the product and process according to the present invention.
The finished structure is a monolithic one and is completely realized
in loco; thus, all problems linked to a special transport and to particular lifting systems
requested for prefabricated elements are eliminated, and a greater safety in the building
yards is obtained. This has been made possible, once the formworks have been laid,
by the new working process, with the final result that extrados beams and slab are
completely integrated into one single structural section, i.e. a monolithic section,
completely realized
in loco. This result improves the times and the realization safety of the works, thus allowing
to obtain a finished product with undiscussed better features that resists to possible
natural catastrophies and of other kind, seismic movements, great showfalls, fire.
The fire resistance of the structures according to the present invention is highly
improved: according to the needs, the structural stability may last two hours or even
longer, against the 20-30 minutes of the precompressed reinforced concrete or steel
structures, which undergo greater structural damage with the risk of an immediate
collapse of said structures.
[0012] The safety degree of the works realized by means of the new process greatly respects
all building laws of the national and European market.
[0013] The new building process allows a reduced time for preparing the formwork structures
in the building yard, thus improving the productivity or the work, and therefore reduced
costs. It favours a more careful analysis of the project and of the realization drawings
of the structures, creating maximum safety conditions for the workers in the building
yard.
[0014] Furthermore, the new working process may be used for building any kind of conventional
plane structures out of reinforced concrete, concerning the building production of
industrial sheds, civil buildings, public works, military works, however with a special
reference to the improvement of the building process by simplifying the mounting of
the supporting bracing of the work
in loco and the course of the building process.
[0015] Other features and advantages of the object of the present invention will appear
more clearly from the detailed specification following hereinbelow, with reference
to the enclosed drawings in which a prefered embodiment is shown.
Figure 1 shows a perspective view of a ceiling according to the present invention.
Figure 2 shows a square section parallel to the extrados beams of the ceiling according
to figure 1.
Figure 3 shows a square section perpendicular to the extrados beams of an enlarged
detail of the ceiling with a full slab.
Figure 4 shows the ceiling of figure 3 with a tightened slab.
Figure 5 shows an enlarged detail of the perimetric jutting out eaves for the collection
of the rain.
Figure 6 shows the same detail of figure 5, with non jutting out eaves.
Figure 7 shows a square section perpendicular to the extrados beams, of an enlarged
detail of the ceiling with a lightened slab, with formworks and props for supporting
the cast of the slab 1 and of the extrados beams 2.
[0016] In the case of small spaces - between 3 and 5 meters - said slab 1 has an advantageously
full section, comprising reinforcing irons or nets 3 englobed in a monolithic cement
cast 4.
[0017] In this case, the insulation material of the ceiling is placed above the full section
slab.
[0018] In the case of great, spaces - between 15 and 40 meters - due to reasons of structural
weight and insulation, polystyrene blocks 5 are advantageously provided in said slab
1, between the upper and lower iron reiforcing.
[0019] The extrados beams 2 comprise a portion of their section inserted inside said slab
1 and a portion projecting above the extrados of said slab.
[0020] Advantageously, said beams are realized with cement concrete and reinforcing irons
6. The reinforcing irons may be of the conventional kind (slow) or postcompressed.
[0021] In a variant according to the present invention, said beams are realized out of iron,
with a full or reticular section, possibly protected with anticorrosive surface treatments.
[0022] The extrados beams 2 are resting onto at least two rows of pillars 7, which determine
the span of the ceiling. Said pillars 7 are advantageously realized out of reinforced
concrete.
[0023] Along the circumference of the ceiling, or at least along one side of the same, eaves
8 are advantageously provided.
[0024] Such eaves may be jutting up or not with respect to the row of pillars 7 and is limited
by a containing wall 9. Furthermore, said eaves comprise holes 10 conected to discharge
down pipes 11. The wall 9 is provided with overflow holes 12 for discharging the water
not discharged by the downpipes 11 due to possible obstructions caused by leaves or
dirt accumulated inside the eaves, and that will prevent with absolute certainty the
water from penetrating the building.
[0025] The process for the realization of a ceiling according to the present invention,
specially with a full slab, is the following:
[0026] The first phase provides the building of rows of carrying pillars 7 out of reinforced
concrete onto plinths 15 or beams or foundation slabs.
[0027] Then the formwork is realized for supporting the slab during the cast and cement
maturation phase.
[0028] Such formwork may be advantageously realized with reusable formworks 13 and props
14, easily available on the market.
Now the conventional reinforcing with a metal net and reinforcing iron rods 6 of said
slab 1 and of said extrados beams 2 is placed.
[0029] Then the cement cast of said slab 1 and of the portion of the extrados beams 2 inserted
inside said slab is performed. The extrados of said slab may be advantageously shaped
with an inclined surface that favours the running of the water towards eaves 8.
[0030] A few days later the frameworks are realized onto said slab, projecting for the completing
of the extrados beams and of the eaves wall in correspondence with the respective
reinforcing projecting from said slab, already provided before the cast of the slab.
[0031] The finishing cast of the portions of the extrados beams external to the slab and
to the eaves wall is performed.
[0032] Finally, the thermic insulating and the waterproof sheeth of known kind may be laid.
[0033] In the case of lightened slab, the realization process of the same initially provides
the realization of a first cement cast englobing the lower reinforcing iron, then
the laying of perforated blocks (shaped blocks) out of polystyrene (or other equivalent
material) and of the upper reinforcing iron, and finally the completing cement cast
of the slab up to the extrados.
[0034] In both kinds of ceiling, openings may be made in the slab for realizing windows
and skylights, as requested by higienic laws.
[0035] According to the present invention, once the project of a monolithic industrial shed
has been studied, the project of the carrying structure of formwork and props for
the slab and the extrados beams must be worked out. This project is necessary for
improving the future safety of the building yard and for reducing the time for assembling
the panels for formworks and props and therefore also improving productivity and reducing
the assembling cost, which is a contributing factor for the final cost of the work.
Once the building yard has been prepared, at first the perimetric pillars 7 are realized
with the relative foundation plinths 15, or beams or slabs, which will carry the whole
monolithic structure. The pillars will have an indicative pitch comprised between
a minimum of 3 meters and a maximum of 15 meters, and for a span of the ceiling in
the other direction, between a minimum of 5 meters to a maximum of 40 meters. The
next phase - once the pillars have been freed from the formwork - is the realization
of the carrying formwork structure 13 and of the props 14 for supporting the full
or lightened slab which, due to building needs, is housed inside the polystyrene blocks
5.
[0036] For the full slab or ceiling, the renforcing 6 is laid and then the cast in one single
solution.
[0037] For the lightened slab, the lower reinforcing is laid and a first cast of 5 cm is
made. Then the polystyrene blocks are laid, with a height variable according to the
work to be performed. After this phase, the upper net may be placed on the polystyrene
and the reinforced concrete cast may be made up to 2.5 cm above the iron, for assuring
the thickness for hiding the iron.
[0038] During the operation of reinforcing the lightened slab (with iron rods and lower
and upper net), the reinforcing for the future realization of the extrados beams may
be prepared, which will remain linked to the reinforcing of the full or lightened
slab.
[0039] Once the worker has completed the formwork of the extrados beams, the third cement
reinforced concrete cast is made for completing the portions projecting beyond the
extrados of the slab of the extrados beams, thus reaching the aim of the present invention,
to realize a monolithic reinforced concrete structure. After a technic time period,
the last phase to be performed in the building yard is the process of removing the
formworks, i.e. removing all formwork panels and all props of the lightened slab of
full celing as well as of the extrados beams.
1. A laid monolithic ceiling out of cement reinforced concrete, characterized in that it comprises extrados beams (2) that cooperate like a monolyth with a cast slab (1).
2. A ceiling according to claim 1, characterized in that the extrados beams (2) comprise a portion of their section inserted inside said slab
(1) and a portion projecting above the extrados of said slab.
3. A ceiling according to claim 1, characterized in that the extrados beams. (2) are out of cement reinforced concrete with conventional low
or post compressed
4. A ceiling according to claim 1, characterized in that the extrados beams (2) are out of iron.
5. A ceiling according to claim 1, characterized in that said slab (1) has a full section comprising reinforcing irons (3) or nets englobed
in a monolithic cement cast (4).
6. A ceiling according to claim 1, characterized in that said slab (1) has a light section comprising blocks (5) of polystyrene placed between
the upper and lower irdon reinforcing.
7. A ceiling according to claim 1, characterized in that at least along one side of the ceiling an eaves (8) is realized that juts out with
respect to row of pillars (7), and which is limited by a containing wall (9) comprising
holes (10) connected to discharge downpipes (11) and overflow holes (12).
8. A realization process for a laid monolithic ceiling out of cement reinforced concrete
comprising a slab and extrados beams,
characterized in that it comprises the following phases:
- the building of at least two carrying pillars;
- the realization of an intrados formwork supported by props;
- the formation of the iron reinforcing of the slab and of the extrados beams;
- the filling of the formworks with cement for the cast of the slab and of the portion
of the extrados beams inserted into said slab;
- the realization of the formwork projecting from the extrados of the slab for the
finishing cast of the extrados beams.
9. A realization process according to claim 8, characterized in that it provides initially the realization of a first cement cast englobing the lower
reinforcing iron, then the laying of lihtening perforated block and of the upper reinforcing
iron, and finally the completing cement cast of the slab up to the extrados.
10. A building characterized in that it comprises a ceiling realized according to the preceding claims.