Note: Descriptions are shown in the official language in which they were submitted.
2119296
MODULAR CONCRETE FLOOR SLAB
The present invention relates to building construction and more
particularly to the fabrication of floors of precast concrete slabs.
The three grade level floor systems most commonly in use are the
Slab-On-Grade system, the Structural Poured-ln-Place system and the Hollow
Core system.
In the Slab-On-Grade system, the building structure is supported
with a perimeter grade beam, usually 8 inches ~20 cm) wide by 24 inches
(60 cm) deep on cast-in-place or driven piles. The slab is of reinforced
concrete, poured in place, and supported on a compacted granular base. It
has been found that floors of this type often experience significant slab
heaving problems. This may cause extensive and costly damage in finished
areas of the building. The Structural Poured-ln-Place and Hollow Core systems
may be used to address this problem.
In the Structural Poured-ln-Place floor system, the building
structure and the floor slab are both supported on a perimeter grade beam,
usually 8 inches (20 cm) by 24 inches (60 cm) deep on cast -in-place or driven
piles. The slab is of reinforced concrete and is supported on the perimetér
grade beam and interior piles. The slab is poured in place over a void form
covered with hardboard. The slab is thickened over and on lines extending
between the supporting interior piles. This system is more expensive and less
convenient to install than the Slab-On-Grade system and consequently is not
always employed where it would be of benefit.
In the Hollow Core system, the building structure and the precast
hollow core slabs are supported with a perimeter grade beam, usually
2 1 1 9296
10 inches (25 cm) by 48 inches (120 cm) deep, on cast-in-place or driven
piles. The slabs are also supported by interior steel or concrete beams on
piles. The joints between slabs are grouted and a topping is poured over the
floor. This is another expensive and inconvenient system to install.
The present invention proposes a novel structural floor system
that does not suffer from the heaving problems of the slab-on-grade system
and that can be installed at less cost than the conventional structural
systems. According to one aspect of the present invention there is
provided a floor system comprising:
a plurality of piles installed in the ground and having coplanar
top surfaces;
a grade level floor comprising a plurality of reinforced concrete
floor slabs, each slab having:
a floor panel,
a polygonal periphery with at least three corners, and
a perimeter beam beneath the floor panel, at the
periphery of the slab,
the slabs being arranged side by side with their floor panels
substantially coplanar and with each slab supported solely at the corners of
the slab by direct engagement of the perimeter beam on the piles.
This structure requires no perimeter grade beam since the floor
slabs themselves have integral perimeter beams for supporting the floor.
Intermediate beams may be used on the bottom of the slab,
preferably radiating from the centre of the slab. The perimeter and
intermediate beams provide the support necessary to minimize slab
thickness and reinforcing. The reinforcement in the perimeter beam may be
used to fasten the slabs to one another and to the reinforcements in the
21 19296
piles. Joints between the slabs and voids at the corners over the piles may
then be grouted and leveled. Where the slabs are finished to finished floor
specifications, no topping or further finishing is required.
The intermediate beams under the slab allow the thinning of the
5 floor panel to reduce the overall amount of concrete used.
Preferred embodiments of the slab are square, with oblique
corners where the reinforcement in the perimeter beam is exposed. Side
faces of the slab taper slightly upwardly for ease of mold release and to
provide a grouting groove between the adjacent slabs.
The invention also relates to a method of forming a floor.
According to this further aspect of the present invention there is provided a
method of manufacturing a floor comprising:
providing a plurality of load-supporting piles in the ground;
providing a plurality of precast concrete floor slabs, each
having a polygonal peripheral shape with a plurality of corners and an
integral, peripheral perimeter beam; and
arranging the floor slabs side by side in an array, with each
corner of each slab being supported directly on a pile.
An exemplary embodiment of the present invention will be
described in the following with reference to the accompanying drawings
wherein:
Figure 1 is a top isometric of a slab according to the present
invention;
Figure 2 is a bottom isometric of the slab of Figure 1;
Figure 3 is a cross section of the slab; and
Figure 4 is a plan view of a floor constructed using the slab.
~",~
- 21 19296
Referring to the accompanying drawings, Figures 1 and 2
illustrate a precast concrete floor slab 10. The slab has a top floor panel 12
that is generally square in outline, with straight side edges 14 and oblique
corners 16. The slab is 12 feet by 12 feet in external dimensions.
Beneath the floor panel 12 is a perimeter beam 18. This
extends around the underside of the floor panel 12, at its periphery. The
perimeter beam has an outer side face 20 that tapers slightly upwardly on all
sides. The inner side face 22 of the perimeter beam slopes upwardly to the
underside of the floor panel 12 at a sharper angle so that the thickness of
the perimeter beam 18 increases upwardly from its bottom surface 24.
Extending across the bottom of the floor panel 12 are intermediate
beams 26. These beams are at right angles to one another and
.~
~ ...~
- 5 - 211yzg6
-
each extends from the centre of the slab to the centre of a respective side of
the perimeter beam. The bottom faces 28 of the intermediate beams are
parallel to the bottom face 24 of the perimeter beam.
The bottom face 30 of the floor panel 12 slopes upwardly
towards the centre from the perimeter beam 18, reducing the thickness of the
floor panel towards the centre.
As illustrated most particularly in Figure 3, the slab 10 is
reinforced using vertically spaced lattices of reinforcing strands 32 extending
across the floor panel 12 and into the perimeter beam 18. These are
conventional reinforcing steel bars. Additional reinforcing stands 34 are
embedded in the intermediate beams ~. Further reinforcing strands 36
extend around the perimeter beam and project from the oblique corner faces
38 of the perimeter beam as loops 40.
In making a floor using the slabs, an array of piles 42 is provided
on a 12-foot grid to match the dimensions of the slab. The piles are cast in
place and have their top surfaces 44 coplanar. The slabs are then arranged on
the piles with each corner of each slab supported on a pile. The slabs are
butted against one another to provide a complete floor separated by narrow
grooves between the upwardly-tapered side faces 20 of the perimeter beams.
The loops 40 of adjacent corners of the slabs are then connected to the
reinforcement of the pile, as by welding, and the grooves 46 and the voids 48
at the corners are grouted and leveled to complete the floor.
The completed floor uses no grade beam. The perimeter beams
are sufficient to support the structural load of the building. The top surface of
the floor panel 12 of each slab is finished to the finished floor specification so
,
- 6- 2119296
that no additional topping layer is required as is the case with other precast
floor types.
The slabs of the present invention may be used to construct
floors for various uses. They may be used, for example, as transformer and
equipment pads, for garage floors, for slab floors of residences and various
commercial buildings. They are expected to be most cost-effective for smaller
building sizes. Slab floors according to the invention may be constructed more
quickly than the conventional structural slab systems. They are not as readily
affected by adverse weather conditions or poor soil conditions.
While one embodiment of the present invention has been
described in the foregoing, it is to be understood that other embodiments are
possible within the scope of the invention. For example, the embodiment of
the slab described in the foregoing is essentially a square slab. Other
polygonal shapes that will assemble to form a floor area may also be used.
For example, triangular, hexagonal or octagonal shapes may be used where
desired. It is therefore to be understood that the invention is to be construed
as limited solely by the scope of the appended claims.
