Note: Descriptions are shown in the official language in which they were submitted.
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PRE-FABRICATED WARPED PAVEMENT SLAB, FORMING AND PAVEMENT
SYSTEMS, AND
METHODS FOR INSTALLING AND MAKING SAME
BACKGROUND OF THE INVENTION
Technical Field
The present invention relates generally to roadway
construction and repair, and more particularly, to the formation;
installation and system for making and attaching a pre-fabricated
warped pavement slab, and the warped slab so formed.
Related Art
Heretofore, attempts have been made to construct and install pre-
fabricated or precast pavement slabs. However, most attempts
have been unsuccessful due to a combination of factors. For
example, it is difficult to prepare and maintain a perfectly
smooth sub-grade, which is necessary to uniformly support the
slab. It is even more difficult to prepare a subgrade that is
warped meeting profile and cross-slope changes normally
encountered in roadway construction. Attempts to make a pre-
fabricated pavement slab with an accurate and predictable warp
have been unsuccessful. Likewise, it is difficult to connect
adjacent slabs in a manner that uniformly transfers shear loading
from one slab to the next. Heretofore attempts to prefabricate
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such pavement slabs have been of an experimental nature and have been entirely
inadequate and inefficient. Accordingly, there exists a need in the industry
for a pre-
fabricated warped pavement slab and a method of installing the warped slab
that solves
these and other problems.
SUMMARY OF THE INVENTION
In a broad aspect, the present invention relates to a system for installation
of a
pre-fabricated pavement slab comprising: an interconnection system along edges
of the
slab and accessible from a top surface of the slab, wherein the
interconnection system
includes at least one interconnection slot, wherein the interconnection system
further
comprises: a plurality of reinforcement bars extending from a first end of the
slab; a
plurality of the at least one interconnection slots formed within the bottom
of the slab at a
second end thereof; and a plurality of at least one interconnection slots
formed within the
bottom of the slab at a first and second side thereof; and a binder
distribution system
formed for attachment of a bottom surface of the slab, wherein the binder
distribution
system includes at least one channel that is independent from and not parallel
with the at
least one interconnection slot, and wherein at least one port extends from the
at least one
interconnection slot to the top surface of the slab and at least one port
extends from the at
least one channel to the top surface of the slab.
In another broad aspect, the present invention relates to a system for
installation
of a pre-fabricated pavement slab comprising: a binder distribution system
formed for
attachment of bottom surface of the slab and accessible from a top surface of
the slab;
and an interconnection system along edges of the slab and accessible from the
top surface
of the slab, wherein the interconnection system comprises: a plurality of
reinforcement
bars extending from a first end of the slab; a plurality of mating
interconnection slots
formed within the bottom of the slab at a second end thereof; and a plurality
of
interconnection slots formed within the bottom of the slab at a first and
second side
thereof, wherein the interconnection slots comprise inverted holes having
rounded tops
and at least one shear pin formed along side of the holes.
In another broad aspect, the present invention relates to a system for
installation
of a pre-fabricated pavement slab comprising: an interconnection system along
edges of
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the slab and accessible from a top surface of the slab, wherein the
interconnection system
includes at least one interconnection slot; a binder distribution system
formed for
attachment of a bottom surface of the slab, wherein the binder distribution
system
includes at least one channel that is independent from and not parallel with
the at least
one interconnection slot, and wherein at least one port extends from the at
least one
interconnection slot to the top surface of the slab and at least one port
extends from the at
least one channel to the top surface of the slab; and a gasket formed along a
perimeter of
the bottom surface of the slab.
In another broad aspect, the present invention relates to a system for
installation
of a pre-fabricated pavement slab comprising: an interconnection system along
edges of
the slab and accessible from a top surface of the slab, wherein the
interconnection system
includes at least one interconnection slot; a binder distribution system
formed for
attachment of a bottom surface of the slab, wherein the binder distribution
system
includes at least one channel that is independent from and not parallel with
the at least
one interconnection slot, and wherein at least one port extends from the at
least one
interconnection slot to the top surface of the slab and at least one port
extends from the at
least one channel to the top surface of the slab; and a reinforcement mat
formed within
the slab substantially near the top surface of the slab.
In another broad aspect, the present invention relates to a system for
installation
of a pre-fabricated pavement slab comprising: an interconnection system along
edges of
the slab and accessible from a top surface of the slab, wherein the
interconnection system
includes at least one interconnection slot; and a binder distribution system
formed for
attachment of a bottom surface of the slab, wherein the binder distribution
system
includes at least one channel that is independent from and not parallel with
the at least
one interconnection slot, and wherein at least one port extends from the at
least one
interconnection slot to the top surface of the slab and at least one port
extends from the at
least one channel to the top surface of the slab; and a reinforcement mat
formed within
the slab substantially near the bottom surface of the slab.
In another broad aspect, the present invention relates to a system for
installation
of a pre-fabricated pavement slab comprising: an interconnection system along
edges of
the slab and accessible from a top surface of the slab, wherein the
interconnection system
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includes at least one interconnection slot, further wherein the
interconnection system is
post tensioned; and a binder distribution system formed for attachment of a
bottom
surface of the slab, wherein the binder distribution system includes at least
one channel
that is independent from and not parallel with the at least one
interconnection slot, and
wherein at least one port extends from the at least one interconnection slot
to the top
surface of the slab and at least one port extends from the at least one
channel to the top
surface of the slab.
In another broad aspect, the present invention relates to a system for
installation
of pre-fabricated pavement slabs comprising: at least one pavement slab,
wherein the at
least one pavement slab comprises a first interconnection on a first side for
attachment of
the first side of the slab and a second interconnection on a second side for
attachment of
the second side of the slab, and wherein one of the first interconnection and
the second
interconnection comprises a slot wherein a width of the slot on an exterior
surface of the
slab is narrower than a width of the slot at an interior portion of the slot.
In another broad aspect, the present invention relates to a method of
installing a
pre-fabricated pavement slab, comprising: providing the slab, wherein said
slab includes
an elongate horizontal binder distribution system formed along a bottom
surface of said
slab; placing the slab on a graded subbase; and distributing a curable binder
material
horizontally along the bottom surface of the slab through said distribution
system via at
least one access in a top surface of the slab.
In another broad aspect, the present invention relates to a method comprising:
determining a theoretical plane on a surface for placement of a pre-fabricated
pavement
slab; grading the surface to the theoretical plane; providing the pre-
fabricated pavement
slab having at least one cavity along a bottom surface; placing the pre-
fabricated
pavement slab on the graded surface, wherein said at least one cavity along
the bottom
surface forms at least one sealed cavity between the bottom surface and the
graded
surface; and distributing a solidifiable binder material in said at least one
sealed cavity.
In another broad aspect, the present invention relates to a method comprising:
providing a roadway subbase; placing a pre-fabricated pavement slab on the
roadway
subbase, wherein a bottom surface of the slab includes a gasket which creates
a seal with
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the roadway subbase, thereby forming at least one sealed cavity, wherein said
seal is
adequate to prevent egress of a binder material from the bottom surface of the
slab.
In another broad aspect, the present invention relates to a method of
installing a
pre-fabricated pavement slab comprising: grading a subbase to within 1/8`h of
an inch
accuracy; placing the slab on the graded subbase, wherein a gasket material on
a bottom
surface of the slab engages, with and forms to seal with, the graded subbase;
and
distributing a binder material between the bottom surface of the slab and the
graded
subbase via at least one opening in a top surface of the slab.
In another broad aspect, the present invention relates to a method of
installing a
pre-fabricated pavement slab, said slab being at least about 10 feet wide and
at least about
feet long, comprising: placing the pre-fabricated slab on a graded subbase,
wherein a
compressible material on the perimeter of a bottom surface of the slab can
prevent the
escape of a binder material from below the slab; and distributing the binder
material in a
chamber between the bottom surface of the slab, the graded subbase, and the
compressible material via at least one opening in a top surface of the slab.
In another broad aspect, the present invention relates to a method of
installing a
pre-fabricated pavement slab, comprising: placing the slab on a graded
subbase; and
distributing a curable binder material along a plurality of voids on a bottom
surface of the
slab, wherein no void along the bottom surface extends either to an end nor to
a side of
said slab.
In another broad aspect, the present invention relates to a method of
installing a
pre-fabricated pavement slab, comprising: providing the slab, wherein said
slab includes
a binder distribution system formed along a bottom surface of said slab;
placing the slab
on a surface; and distributing a curable binder material along a bottom
surface of the slab
through said distribution system via at least one access in a top surface of
the slab,
wherein said distributed binder material does not extend beyond a perimeter of
the slab.
In another broad aspect, the present invention relates to a method of
installing a
pre-fabricated pavement slab, comprising: providing the slab, wherein said
slab includes
a binder distribution system formed along a bottom surface of said slab;
placing the slab
on a surface; distributing a curable binder material along a bottom surface of
the slab
through said distribution system via at least one access in a top surface of
the slab; and
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attaching at least one gasket on the bottom surface of the slab, wherein said
at least one
gasket is configured to form at least one scaled cavity with a portion of the
bottom
surface of the slab and the surface for placing.
BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments of this invention will be described in detail, with reference
to
the following figures, wherein like designations denote the like elements, and
wherein:
Fig. I depicts a plan view of a pre-fabricated pavement slab in accordance
with
the present invention;
Fig. 2 depicts a cross-sectional view of the pre-fabricated pavement slab in
accordance with the present invention;
Fig. 3 depicts a cross-sectional view of a transverse dowel bar in accordance
with
the present invention;
Fig. 4A depicts a cross-sectional view, taken along line 4-4 of Fig. 1, of a
connector slot in accordance with embodiments of the present invention;
Fig. 4B depicts Fig. 4A using an alternative connector slot in accordance with
embodiments of the present invention;
Fig. 4C depicts Fig. 4A using an alternative connector slot in accordance with
embodiments of the present invention;
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Fig. 5 depicts a cross-sectional view, taken along line 55
of Fig. 1, of a channel in accordance with embodiments of the
present invention;
Fig. 6 depicts a cross-sectional view, taken along line 6--6
of Fig. 1, of the channel in accordance with embodiments of the
present invention;
Fig. 7 depicts a cross-sectional view, taken along line E-E
of Fig. 1, of a connector slot in accordance with the embodiments
of the present invention;
Fig. 8A depicts a cross-sectional view, taken along line 8-8
of Fig. 1, of a connector slot in accordance with embodiments of
the present invention;
Fig. 8B depicts Fig. 8A using an alternative connector slot
in accordance with embodiments of the present invention;
Fig. 8C depicts Fig. BA using an alternative connector slot
in accordance with embodiments of the present invention;
Fig. 9 depicts a top mat in accordance with the present
invention;
Fig. 10 depicts a bottom mat in accordance with the present
invention;
Fig. 11 depicts a gasket in accordance with the present
invention;
Fig. 12 depicts Fig. 11 using additional sections of a
gasket in accordance with embodiments of the present invention;
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Fig. 13A depicts a cross-sectional view of a dowel and an
existing slab in accordance with embodiments of the present
invention;
Fig. 13B depicts a cross-sectional view of a two-piece
connector and an existing slab in accordance with embodiments of
the present invention;
Fig. 13C depicts a plan view of a slot cut in an existing
slab in accordance with the present invention;
Fig. 13D depicts a cross-sectional view of a slot cut in an
existing slab in accordance with the present invention;
Fig. 14 depicts a grading device used in accordance with the
present invention;
Fig. 15 depicts a form used to construct the slab in
accordance with the present invention;
Fig. 16 depicts a perspective view of a warped slab in
accordance with the present invention;
Fig. 17A depicts a side view of a side of a warped slab in
accordance with the present invention;
Fig. 17B depicts a side view of an end of a warped slab in
accordance with the present invention;
Fig. 18 depicts a perspective view of a portion of a forming
system in accordance with the present invention;
Fig. 19 depicts a side sectional view of a portion of a
forming system in accordance with the present invention;
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Fig. 20 depicts a perspective view of a moveable jacking
beam portion of a forming system in accordance with the present
invention;
Fig. 21A depicts a plan view of a portion of a forming
system in accordance with the present invention;
Fig. 21B depicts a plan view of a portion of a forming
system in accordance with the present invention;
Fig. 22A depicts a side view of a roller assembly portion of
a forming system in accordance with the present invention;
Fig. 22B depicts a side view of a roller assembly portion of
a forming system in accordance with'the present invention;
Fig. 23A depicts a side view of a mobile jacking trolley
portion of a forming system in accordance with the present
invention;
Fig. 23B depicts a side view of a mobile jacking trolley
portion of a forming system in accordance with the present
invention;
Fig. 24A depicts a side view of a portion of a forming
system in accordance with the present invention;
Fig. 24B depicts a side view of a portion of a forming
system in accordance with the present invention;
Fig. 25 depicts a plan view of a portion of a forming system
in accordance with the present invention; and
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Fig. 26 depicts a perspective view of a portion of a side
rail of a forming system in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
Although certain embodiments of the present invention will
be shown and described in detail, it should be understood that
various changes and modifications may be made without departing
from the scope of the appended claims. The scope of the present
invention will in no way be limited to the number of constituting
components, the materials thereof, the shapes thereof, the
relative arrangement thereof, etc. Although the drawings are
intended to illustrate the present invention, the drawings are
not necessarily drawn to scale.
Referring to the drawings, Fig. 1 shows a plan view of a
pre-fabricated pavement slab 10. The slab 10 may be constructed
by pouring a pavement material, such as concrete, or other
similarly used material, into a form 60, having a plurality of
raised channel forming surfaces 62, raised slot forming surfaces
64, connector openings 66 and port forming surfaces 68 (refer to
Fig. 15). The raised channel forming surfaces 62 may be
independent from the raised slot forming surfaces 64. The slab
may be used in high traffic areas, such as highways, on/off
ramps, airport runways, toll booth areas, etc. The pavement slab
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can vary in length and width. The length of the pavement slab
10 can be in the range from 1 foot up to 18 feet. The width of
the pavement slab 10, likewise, can vary from a width of 2 feet
up to 12 feet wide. A typical pavement slab 10 for use in a
highway roadway may be approximately 10-12 feet (3.049-3.658 m)
wide W, as required by the New York State Department of
Transportation, and approximately 18 feet (5.486 m) in length L,
for example. Similarly, a pavement slab 10 which has dimensions
of approximately 2 feet in length by a full roadway lane (e.g.,
12 feet) wide can be installed to replace a damaged or
deteriorated roadway joint. Additionally, a pavement slab 10 may
have dimensions, for example, of approximately 2 feet in length
by 2 feet in width, which would be useful as a roadway
replacement patch. The slabs 10 may range in thickness T from
approximately 9-12 inches. These dimensions, L, W, T, however,
may vary as desired, needed or required and are only stated here
as an example.
The top surface 9 of the slab 10 is a roughened astroturf
drag finish, while the sides lla, lib, llc, lid, and bottom
surface 13 of the slab 10 have a substantially smooth finish
(refer to Fig. 2, which shows a cross-sectional view of a corner
of the slab 10). The bottom surface 13, the sides 11a, lib, 11c,
lid of the slab 10 come together to form a chamfer 15 around the
perimeter of the slab 10. The chamfer 15 prevents soil build-up
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between two mating slabs which may occur if the slab 10 is tipped
slightly during installation.
The slab 10 further includes a plurality of connectors 12
that may comprise transverse slippable connecting rods or dowelsõ
The plurality of connectors 12 may be embedded within an end of
the slab 10. In one embodiment, the connectors 12 are post
tensioned interconnections, as known and used in the industry,
wherein multiple slabs may be connected in compression. The
connectors 12 are spaced approximately 1 ft. apart along the
width W of the slab 10, and comprise steel rods, or other similar
material conventionally known and used. Each connector 12 is of
standard dimensions, approximately 14 inches in length and 1.25
inches in diameter. The slippable connectors 12 are mounted
truly parallel to the longitudinal axis L of the slab 10 to allow
adjacent slabs 10 to expand and contract without inducing
unwanted damaging stresses in the slabs 10. The connectors 12
[are preferentially] can be mounted such that approximately half
of the connector 12 is embedded within the pavement slab 10 and
half of the connector 12 extends from the side of the slab 10.
Fig. 3 shows a cross-sectional view (along line A-A of Fig.
1) of the slab 10 and a connector 12 extending therefrom. As
illustrated, the connectors 12 are embedded within the side lid
of the slab 10 at approximately the midpoint of the thickness T
of the slab 10. The connectors 12 aid in transferring an applied
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shear load, i.e., from traffic, evenly from one slab 10 to the
adjacent slab, without causing damage to the slab 10.
The slab 10 further includes a plurality of inverted
interconnection slots, 14 formed within the bottom surface 13 of
the slab 10 at a side 11c thereof. Each interconnection slot 14
is sized to accommodate the connectors 12 extending from the side
of an adjacent slab 10, thereby forming an interconnection
between adjacent slabs once the slot 14 is filled around the
connectors 12 with a binder material. Fig. 4A shows a cross-
sectional view (along line B-B of Fig. 1) of an interconnection
slot 14, wherein the slot 14 is wider at the top of the slot.14
than at the bottom of the slot 14. This wedged shape prevents
the slab 10 from moving downward with respect to the adjacent
slab with the application of a load once the binder material has
reached sufficient strength.
In the alternative, the interconnection slots 14 may take
the form of a "mouse hole" having a pair of cut-outs or holes 17
formed on both sides thereof, as illustrated in Fig. 4B. In this
case, when the slots 14 are filled with a binder material, the
holes 17 form shear pins on the sides of the mouse hole that
would have to be sheared in order for the slab 10 to move
downward with respect to the adjacent slab. In the alternative,
the slots 14 may have vertically oriented sides, as illustrated
in Fig. 4C. In this case the sides of the slot 14 are
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sandblasted to provide a roughened surface, thereby frictionally
limiting the ability of the slab 10 to move downward with respect
to the adjacent slab.
.As illustrated in Figs. 4A-4C, each interconnection slot 14
further includes an opening, access or port 16. In particular, a
binder material such as structural grout or concrete, a polymer
foam material, or other similar material, may be injected within
each port 16 thereby filling the interconnection slot 14
receiving the inserted connector 12 (not illustrated) to secure
adjacent slabs end to end.
It has been previously noted that the connectors 12 are
preferentially mounted as described above with approximately half
of the connector 12 embedded in an adjacent slab while the other
half is engaged and embedded in the interconnections slots 14 of
slab 10. Alternatively, the same connector 12 may be preplaced
on the subgrade, not shown, such that interconnections slots 14
in both slabs engage the connectors 12, such interconnection
slots 14 being subsequently filled with binder material in the
same manner described in the foregoing.
The slab 10 further includes a plurality, in this example
three, channels 18 running longitudinally along the length L of
the slab 10. The channels 18 formed within the bottom surface 13
of the slab 10 facilitate the even dispersement of a bedding
material, such as bedding grout or concrete, a polymer foam
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material, or other similar material, to the underside of the slab
10. As shown in Fig. 5, which depicts a cross-sectional view of
the slab 10 (along line 5-5 of Fig. 1), each channel 18 includes
a port 20 at each end of the channel 18 (one end shown in Fig.
5). Each port 20 extends from the top surface 9 of the slab 10
to the channel 18, thereby providing access to the channel 18
from the top surface 9 of the slab 10. This facilitates the
injection of bedding material beneath the bottom surface 13 of
the slab 10 via ports 20 which are accessible from the top
surface 9 after the slab 10 has been installed.
As illustrated in Fig. 6, which shows a cross-sectional view
of the channels 18-along a line 6-6 of Fig. 1, the channels 18
are in the shape of half round voids. The rounded shape aids in.
the uniform distribution of bedding material along the bottom
surface 13 of the slab 10 to fill any gaps between the slab 10
and the subbase (not shown). In the alternative, the channels 1.8
.may take other shapes, such as rectangles, etc. Furthermore,
instead of using channels 18 to facilitate the even dispersement
of the bedding material beneath the slab 10, a pipe system may be
used. For instance, the pipe system (not shown) may comprise a
plurality of pipes, approximately one inch in diameter, having
holes or continuous slots formed therein.
The slab 10 further includes a plurality of interconnection
slots 24, shown in this example within a first side Ila of the
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}
slab 10 (Fig. 1). The slots are illustrated more clearly in
Figs. 7 and 8A-8C. In particular, Fig. 7 shows a cross-sectional
view of an interconnection slot 24 taken along a line 7-7 of Fig.
1. As illustrated, each interconnection slot 24 comprises a pair
of openings, accesses or ports 26 at each end of the slot 24
which extend from the top surface 9 of the slab 10 to the
interconnection slot 24 thereunder.
The slab 10 further includes a plurality of connectors 69
that may comprise longitudinal connectors, non-slippable
connecting rods or dowels embedded within a second side llb of
slab 10 along the length L of the slab'10. As with the
connectors 12, the connectors 69 may be post tensioned
interconnections. The connectors 69 may be one-piece, where
approximately half of the connector 69 is embedded within the
pavement slab 10 and half of the connector 69 extends from the
second side lib of the slab 10. Alternatively, the connector 69
may be of a two-piece design comprising a first connector 54 and
a second connector 56 as shown in Fig. 13B. The two-piece design
would be used if it is desirable to keep shipping width of slab
to a minimum.
Fig. 8A depicts a cross-sectional view of the
interconnection slot 24 and port 26 along line 8-8 of Fig. 1.
Similar to the interconnection slots 14 along the sides 11c, lid
of the slab 10 (shown in Figs. 4A-4C), the interconnection slots
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24 along the sides lla, lib of the slab 10 may alternatively take
the form of a mouse hole 24 having cut-outs or holes 25 .(Fig.
8B), or a slot 24 having vertically oriented sandblasted sides
(Fig. 8C). The interconnection slots 24 receive connectors 69
that may comprise non-slippable connecting rods or dowels located
within and extending from an adjacent new slab 10 or from an
existing slab 50, such has been described embedded in the second
(i.e., other) side llb of slab 10.
After the slab has been installed and the connectors are in
their final location, a binder material, such as structural
cement-based grout, a polymer foam, etc., is then injected into
the interconnection slots 24, having the rods inserted therein,
from the top surface 9 of the slab 10 via the ports 26. This
aids in rigidly interconnecting adjacent slabs of the roadway and
facilitates a relatively even load transfer between lanes.
The slab 10 further includes a top mat 32 and a bottom mat
34 (Figs. 9 and 10, respectively). Both mats 32, 34 comprise
reinforcing bars, or in the alternative reinforced steel mesh.
The top mat 32, comprising longitudinal bars 31 and at least two
transverse or cross bars 29, is formed within the slab 10
substantially near the top surface 9 of the slab 10.- The top mat
32 aids in minimizing the slab 10 from "curling" or bending at
the edges as a result of cyclic loading produced by temperature
differentials. Likewise, the bottom mat 34 comprises
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longitudinal bars 33 and transverse or cross bars 35 formed
within the slab 10 substantially near the bottom surface 13 of
the slab 10. The bottom mat 34 provides the slab 10 with
additional reinforcement and stability during handling.
A seal or gasket 36, comprising a compressible closed cell
foam material, such as neoprene foam rubber or other similar
material, is attached to the bottom ,surface 13 of the slab 10
around the perimeter of the slab 10, as illustrated in Fig. 11.
In one embodiment, the gasket 36 is approximately 18 mm thick and
25 mm wide, and is soft enough to fully compress under the weight
of the slab 10. The gasket 36 forms a chamber or cavity 38
thereby sealing the boundary of the slab 10. This allows for the
application of pressure to the bedding material during
installation to ensure that all voids between the bottom surface
13 of the slab 10 and the subbase are filled.
In another embodiment, the gasket 36 can be made from a
material selected of such a softness so that the slab 10 is held
up a predetermined amount so as to create a design space for
grout or other bedding material to be inserted. The softness of,
the selected material for the gasket 36 in this embodiment will
conform so that the top surface 9 and bottom surface 13 of the
slab 10 is held generally parallel to the surface of the prepared
subgrade. This embodiment is useful when the subgrade, rather
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than compacted stone dust, is a dense graded base, as discussed
below.
Optionally, additional sections of the gasket 36, having the
same or similar width and thickness, may be applied to the bottom
surface 13 of the slab 10 to form a plurality of individual
chambers or cavities 38, as illustrated in Fig. 12. The
additional sections of the gasket 36 forming the cavities 38.
reduce the amount of upward pressure exerted on the slab 10
during the injection of the bedding material as compared to that
experienced by the slab 10 using one large sealed cavity (as
illustrated in Fig. 11). Forming at least 3 to 4 cavities 38
effectively reduces the lift force produced from below the slab
as the bedding material is being forced thereunder.
In an alternative embodiment (not shown) of the present
invention, a different binder distribution system is employed.
In lieu of gasket material 36, a geotech fabric, or the like, is
used to hold the binder material. For example, two layers of.a
geotech fabric is attached to the slab 10 in various-locations.
The layers of geotech fabric may be additionally attached to each
other in selective locations thereby forming pockets between the
fabric layers which receive the pumped in grout. In addition,
the bottom surface 13 of the slab 10 may be flat. The geotech
fabric thus acts as a series of chambers to hold and distribute
the grout, or similar binder material. In another embodiment, a
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single layer of geotech fabric is attached to the slab 10. Thus,
the grout,.or binder material, is pumped between the geotech
fabric and the bottom surface 13 of the slab 10.
To install the slab 10, connectors 12 may first need to be
installed along the transverse end of the existing slab 50,. and
connectors 69 may need to be installed along the longitudinal
side of the existing slabs 50, to match interconnection slots 14
and 24, respectively. If so, a hole may be drilled within the
existing slab 50, using carbide tipped drill bits, or other
similar tools. Thereafter, the connector 12 or the connector 69
is inserted within each hole, along with a binder material, such
as a cement-based or epoxy grout, polymer foam, etc., such that
approximately one half of the connector 12 or the connector 69
extends therefrom, as illustrated in Figs. 3 and 13A,
respectively. Slab 10 and existing slab 50 may be the same
structurally and., both slab 10 and existing slab 50 may have
interconnect slots and/or connectors.
Alternatively to installing connectors 12 and connectors 69
in the existing slab to mate with the interconnection slots 14
and 24 in the slab 10, the same connectors 12 and connectors 69
may be embedded in the slab 10 such that they extend from the
slab 10 as described above. In this case,.a vertical slot 70 is
cut in the existing slabs 50 using a diamond blade concrete saw,
or other similar tool, in locations corresponding to the extended
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j
connectors 12 and connectors 69 in slab 10 (refer to Figs. 13C
and 13D). The sawing operation would be done ahead of the slab
installation operation. The slots 70 would be opened up and
burrs removed using a light-weight pneumatic chipping hammer, or
other similar tool. This option would be chosen to avoid the
above described drilling process that should be done during the
night-time grading operation.
In preparation for slab installation, the replacement area
(the area in which the slab 10 will be placed) is cleaned of all
excess material to:provide a subbase or sub-grade approximately
25 mm below the theoretical bottom surface 13 of the slab 10.
The subbase is graded with conventional grading equipment such as
a grader, backhoe, skid steer loader, etc., and fully compacted
with a vibratory roller or other similar device. The compacted
subgrade is subsequently overlaid with approximately 30mm of
finely graded material such a stone dust that can be easily
graded with the precision grading equipment described below.
The stone dust is then graded with a grading device, such as
the Somero Super GraderTM (Somero Enterprises of Jafrey,New
Hampshire), as illustrated in Fig. 14. The Somero Super Grader TM
is controlled by a rotating laser beam, or 3-D total station,
that is continuously emitted by a laser transmitter 42, located
at a remote location and at least 6-8 feet above ground level-
The transmitter is adjusted to emit a beam of unique cross-slope
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and grade corresponding to the plane required for the slab 10.
The cross-slope allows for water run-off and the grade represents
the longitudinal slope required for vertical alignment of the
roadway.
For straight highways, where the cross-slope and the grade
are constant, the rotating laser beam set as described above will
serve to set multiple slabs. For both horizontally and
vertically curved highways the rotating laser beam will have to
be set to a distinct plane for each slab. This continuous
adjustment may be done manually or automatically with software
designed for that specific purpose. Alternatively, the screed
may by controlled by other electronic means unique to the Somero
Super GraderTM
Specific to the Somero Super GraderTM, laser receivers 44,
mounted on posts 46 above the screed 48, receive and follow the
theoretical plane emitted from the transmitter 42 as the grading
screed 48 is pulled over the. replacement area leaving the stone
dust approximately 3/4" high. After the first grading pass, the
stone dust layer is damped with water and fully compacted with a
vibratory roller or other similar device and a second, and final,
grading ("shaving") pass is made in which the subbase is brought
to within 1/16th of an inch (or "Super-Graded") of the required
theoretical plane. The stone dust layer is dampened with water,
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as needed for the subsequent grouting process, in final
preparation for installation of the slab 10.
In an alternative embodiment, the layer of finely grade
material such as stone dust is omitted. In lieu of the stone
dust, a dense graded base is placed in two lifts. The first lift
is placed about 1" lower than theoretical elevation. It is then
wetted and rolled such that its final average elevation is
slightly lower than the required final elevation of the bottom
surface 13 of the slab 10. The second lift is super graded in a
similar fashion to an elevation slightly higher (e.g., 1/4") than
theoretical elevation and wetted and rolled as required in final
preparation for installation of the slab 10. The second lift of
dense graded base typically cannot be supergraded ("shaved")
after is has been wetted and rolled because unlike the stone dust
the dense graded base has variable size and larger stone that
would get pulled up from the subgrade. Thus, when dense graded
base is used as a subbase material, the finished surface is more
apt to be slightly rougher in that there will exist larger stone
that sticks up above the surface of the rest of the field of
dense graded base. It is because of these projecting stones,
that the embodiment for the gasket 36 material discussed above
that is not fully compressible is used. The non-fully
compressible gasket 36 is able to mold around and conform to the
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projecting stones in the final graded dense graded base without
changing the final average elevation of the placed slab 10.
The slab 10 is placed within the replacement area such that
the slab 10 contacts the subbase uniformly so as not to disrupt
the subbase or damage the slab 10. During placement, the slab 10
is lowered vertically to the exact location required to match the
adjacent existing slabs 50. Care is taken to insure the
interconnection slots 14 and 24, within the sides and end (if an
adjacent slab is present at the end of the slab 10) of the slab
are lowered over the connectors 12 and connectors 69 extending
from the ends and sides of the adjacent slabs 50 respectively.
In the case where connectors 12 and connectors 69 extend from the
slab 10, the slab 10 is also lowered vertically and carefully to
insure the connectors 12 and connectors 69 are set within the
slots 70 of the adjacent existing slabs 50. At this time, the
slab 10 should be within 6+/- mm of the theoretical plane emitted
from the rotating laser transmitter 42. In the event the surface
9 of the slab 10 is out of the required tolerance it is planed
with a conventional diamond grinder until it is brought within
tolerance.
The interconnection slots 14, 24 or 70, as the case may be
are filled from the top surface 9 of the slab 10 with a binder
material such as structural grout, or in. the alternative, a
polymer foam material, thereby fastening the slab 10 to the
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connectors 12, 54, 56, 69 or the slot 70 of the adjacent existing
slabs 50. In particular, the binder material is injected under
pressure into a first port 16, 26 of the interconnection slots
14, 24, respectively, until the binder material begins to exit
the port 16, 26 at the other end of the interconnection slot 14,
24. It is desirable for the binder material within the slots 14,
24 to reach sufficient strength to transfer load from one slab to
the other before opening the slab 10 to traffic.
The chamber(s) 38 formed by the gasket 36 on the bottom
surface 13 of the slab 10 is/are then injected from the top
surface 9 of the slab 10 with bedding material, such as grout
including cement, water and fly ash, or in the alternative with a
polymer foam material. In particular, starting from the lowest
or downhill region, bedding material is injected into the port. 20
at one end of the channel 18 until the bedding material begins to
exit the port 20 at the other end of the channel 18. The bedding
material is injected into the channels 18 to ensure that all
voids existing between the bottom surface 13 of the slab 10 and
the subbase, regardless of size, are filled. The slab 10 should
be monitored during injection of the bedding material to ensure
the slab 10 is not vertically displaced due to the upward
pressure created thereunder. It is desirable for the bedding
material under the slab 10 to reach a minimum strength of
approximately 10.3 MPa before opening the slab 10 to traffic.
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It should be noted that due to the precision of the Super
Graded subbase, the channels 18 may not need to be filled prior
to exposure of the slab 10 to traffic. Rather, the channels 18
may be filled within 24-48 hours following installation of the
slab 10 without damaging the slab 10 or the subbase. In other
words, if required, vehicular traffic can be allowed on the slabs
immediately after the placement of the'slabs 10. This is
particularly useful due to time constraints.
A warped slab is defined as a slab that has a warped
surface. A slab being a body of uniform thickness in which the
sides are substantially perpendicular to both the top and bottom
surfaces. A warped surface being a surface in which all the
points of the surface are not in a single plane. That is, the
slab is not entirely planar, but warped. For example, with a
rectangular-shaped warped slab, three of the four corners of the
slab could be in a single plane. The fourth corner conversely
would not reside in this same single plane. This fourth corner
would be either "higher" or "lower" in relationship to the plane
in which the other three corners reside. With the warped slab,
typically both the top and bottom surfaces are parallel and
warped. Thus, the warped slab's top and bottom surfaces will
both match and be substantially parallel to the surface of the
subgrade on which the warped slab is placed. A warped slab is
further defined wherein all the edges are straight, wherein an
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edge is the intersecting line between any side and either the top
or bottom surface of the slab. Further, with a warped slab, when
any cross section is taken that is perpendicular to a
longitudinal side, the resultant edges (i.e., the lines at the
top and bottom surface of the cross-sectional "cut") will
likewise be straight lines. Conversely, if a diagonal (i.e.,
non-perpendicular) cross section is taken of the warped slab, the
resultant edges (i.e., the lines at the. top and bottom surface of
the cross-sectional "cut") will not be straight, but non-linear.
The use of a warped slab in roadway construction is
typically called for when the cross-sectional slope of a road
lane changes over the longitudinal length of the roadway slab.
Similarly, a warped slab in roadway construction could also be
used when the roadway lane is both curved over the longitudinal
length of the roadway slab and has a change in elevation over the
longitudinal length (i.e., profile change) of the roadway slab.
Prefabricated warped pavement slabs could be used, for example,
both over subgrade in a roadway as well as in an elevated
condition such as bridge, viaduct, or parking garage
construction.
The present invention is able to make precision pre-
fabricated warped pavement slabs with precision tolerances
throughout the whole plan area of the slab. The device is able
to thus make prefabricated pavement slabs either in a flat slab
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configuration or a warped slab having a total warp in the range
from 3-4 mm to approximately 3 inches. Although the shape, in
plan, of the warped slab can be rectangular, other non
rectangular shapes are readily attainable with the present
invention. Another advantage of the present invention is the
ability to construct a pre-fabricated warped pavement slab
wherein the warp in the slab matches precisely and uniformly
throughout the whole area of the slab a predetermined warp
required for the specific roadway section being built, as well
as, precisely matching the warp of the entire subgrade in the
location where the slab will be placed. Another advantage of the
present invention is the ability to quickly install prefabricated
pavement slabs in their final.location and to allow vehicular
traffic use the installed pavement shortly after the
installation.
FIG. 16 shows a perspective view of a pre-fabricated warped"
pavement slab, designated as 100. The top,9 of the warped slab
100 is shown as are some of the sides 11. A rectangular pre-
fabricated warped pavement slab 100 is shown. However, pre-
fabricated warped pavement slabs 100 can be made with different
footprint shapes (i.e., non-rectangular). The pre-fabricated
rectangular warped pavement slab 100 has four corners 102 (i.e.,
102A, 102B, 102C, 102D). The first corner 102A, or non-planar
corner, is shown lifted above the planar surface of the other
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three corners 102B, 102C, 102D. Thus, the first corner 102A is
out of plane with the other three corners 102B, 102C, 102D. A
flat slab with all four corners 102 in the same plane is shown in
phantom. Although in FIG. 16 the first corner 102A is shown
above the other three corners 102B, 102C, 102D, the first corner
102A could conversely be lower than the other three corners 102B,
102C, 102D. Similarly, the non-planar corner could be any one of
the other three corners of the pre-fabricated warped pavement
slab 100 instead of just the first corner 102A, since any three
corner define a plane.
FIGS. 17A and 17B show side views of a pre-fabricated warped
pavement slab 100. The non-planar corner 102A is shown higher
than the rest of the warped slab 100. The top and bottom edges
(i.e. intersecting line between sides 11 and top surface 9 and
bottom surface 13) of all the sides 11 of the pre-fabricated
warped pavement slab 100 are straight. Similarly, if a cross-
section was taken of the warped slab 100 at any location along
the warped pavement slab 100, wherein the cross-section is taken
perpendicular to a side 11, the resultant edges will similarly be
straight-
In order to create a pre-fabricated warped pavement slab 100
a portion of the formwork must be placed out of the plane of the
remaining planar portion of the formwork. This is done by
lifting, or lowering, the corner, or area of the formwork which
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must be moved out of plane from the remaining planar portion of
the formwork. The formwork for making the pre-fabricated warped
pavement slabs 100 have an advantage.of.being at a remote
location. That is the formwork can be adjacent, or on the
applicable construction project, or at a remote location wherein
additional quality controls and assurances can more readily take
place.
FIG. 18 depicts a perspective view of a portion of a pre-
fabricated warped pavement form system 110. In this embodiment,
there are five individual form sections 170 (e.g., 170A, 170B,
170C, 170D, 170E) each made up, in part, of three vertical
stiffeners 172 spaced uniformly extending the length of the form
sections 170. The stiffeners 172 of adjacent form sections 170
are mated together and attached to each other via a series of
four bolts 173 spaced evenly along the stiffeners 172. At either
end of the form section 170 are end caps 175. A device for
adjusting 120 is shown adjusting one corner of the form system
110 out of plane with the other three corners, thus creating a
warped form system 110. The form system 110, now warped, will
then be able to construct a pre-fabricated warped pavement slab
100. The warp-adjusting device 120 can either lift, or lower,
the form system 110 out of plane with the other three corners.
Although this embodiment depicts a form system 110 with five form
sections 170, any quantity of form sections 170 can be employed
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such that adequate flexure is accomplished throughout the form
system 110 upon the placement of the adjusting device 120 to the
form system 110. Similarly, although four bolts per mated
stiffener 172 is depicted, any quantity of connection means and
any type of connection means can be employed to effectively
connect the plurality of form sections 170 together.
Beneath the plurality of form sections 170 is equipment
which, in part, comprise the device for adjusting 120 the warp of
the form system 110. FIG. 19 shows a sectional side view of a
portion of the form system. A device for adjusting a warp of the
form system, such as the mobile jacking trolley 120 is shown
which lifts a jacking beam 140 which in turn lifts the plurality
of form sections 170. On top of the form sections 170 are a
plurality of side rails 160, between which the hardenable,
flexible material (e.g., concrete) is placed. Underneath the
form sections 170 are two support beams 150, a first support beam
150A, and a second support beam 150B. The support beams 150 rest
on a plurality of concrete bases 190. On top of the first
support beam 150A is a half round 153 which mates with one, of
two, pivot plates 178. The first support beam 150A is moveable
and thus, depending on the width of the warped slab 100 desired,
can be moved to various locations on the concrete base 190. The
half round 153, depending on the location of the first support
beam 150A, engages with one of the pivot plates 178. The other
FORT-3365 29
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end of the form sections-170 rest on.a second support beam 150B.
The second support beam 150B, similarly, rests on a concrete base
190. In an embodiment, the second support beam 150B is located
at a lower elevation (e.g., approximately 2-3 inches) than the
first support beam 150A. The second support beam 150B serves as
a support for the form sections and side rails 160 while the
jacking beam 140 is being rolled into position.. The side rails
160 are moved into a desired configuration of the shape of the
desired warped slab 100. Then the jacking beam 140 is moved into
place via the jacking trolleys 120 so that it is underneath and
aligns with the edge of the desired warped slab 100 which will
receive the warp adjustment. Thus, the jacking beam 140 will be
underneath and aligned under one of the side rails 160 where in
the warping will take place. The jacking beam 140 is lifted to
the desired elevation such that the form sections 170 and side
rails 160 are out of level (level is shown in phantom). Once the
form sections 170 and side rails 160 are moved to the correct
elevation, the threaded rod 151, clevis 154, and wing nut 152
combination located at the second support beam 150B are tightened
thereby lashing down the warped end of the form sections 170 to
insure they conform to the straight-line definition at the
jacking beam 140 and to prevent any unwanted uplift on the form
sections 170 and the second support beam 150B. In other words,
the threaded rod 151, clevis 154 and wing nut 152 combination
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keep, in part, the form system 110 at the predetermined, exact
amount of warp. The form sections 170 can be either raised or
lowered out of level, thus creating the desired warped condition.
A perspective view of a typical jacking, or floating, beam
140 is depicted in FIG. 20. This particular embodiment of the
jacking beam 140 has a half round 141 on the top of the jacking
beam 40. The half round 141 assists in providing a narrower
point of contact between the jacking beam 140 and the bottom of
the form sections 170, to which the jacking beam 140 will provide
the adjusting force. Although a square tube shape is shown for
the jacking beam 140, other shapes and configurations can be
employed.
FIGS. 21A and 21B shows a plan view of a portion of the
forming system 110. A portion of the form sections 170 are shown
in phantom. The plurality of mobile jacking trolleys 120A, 120B
can move within trolley tracks 128A,.128B respectively.
Similarly, the jacking beam 140 is moved laterally into place via
a plurality of roller assemblies 130A, 130B which ride on roller
tracks 138A, 138B respectively. When the jacking beam 140 is not
in contact with the form sections 170, the jacking beam 140 can
be moved to the desired placement location, via the pair of
roller assemblies 130A, 130B. The roller assemblies 130A, 130B
operate along the pair of roller tracks 138A, 138B. Similarly,
the mobile jacking trolleys 120A, 120B operate along a pair of
FORT-3365 31
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trolley tracks 128A, 128B. Thus, the jacking beam 140 can be
moved into a plurality of locations under the form sections 170,
only two of which are shown in FIGS. 21A and 21B, depending on
the desired plan view dimensions of the slab 100. This is done
by moving the roller assemblies 130A, 130B along the roller
tracks 138A, 138B. Once the jacking beam 140 is in the desired
location, at least one of the series of mobile jacking trolleys
120A, 120B can be employed to adjust the jacking beam 140 out of
level, thereby causing the forming system 110 to become warped.
FIGS. 22A and 22B depict side views of a typical roller
assembly 130 operating along the roller track 138. The roller
assembly 130 includes a roller assembly 130, for example made by
Hilman (Hilman Rollers of Marlboro, NJ), and a plurality of
extensions 131 which assist in keeping the jacking beam 140 in
place over the roller assembly 130 during its movement along the
roller track 138. Although a wide flange beam 138 is depicted,
other various shapes and items can be used for the roller track
138.
FIGS. 23A and 23B similarly depict side views of the mobile
jacking trolleys 130. The mobile jacking trolleys 130 are used
to adjust a portion of the jacking beam 140 out of level, either
by lowering or raising the jacking beam 140 out of level. The
out of level jacking beam 140, in turn, via its contact through
the half round 141 can adjust the forming sections 170 such that
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it becomes warped. The mobile jacking trolleys 120 includes a
plurality of spring-loaded casters 125 attached to a trolley base
122 on which resides a plurality of devices. On the trolley base
122 are a plurality of hydraulic cylinders 123 and screw jacks
121. The hydraulic cylinders 123 can provide lifting means to
the jacking beam 140. The screw jacks 121 can hold the jacking
beam 140 in place, once the hydraulic cylinders 123 have lifted
the jacking beam 140 to the appropriate elevation. The beam
followers 126 assist in keeping the jacking beam 140 over the
jacking trolleys 120. The mobile jacking trolleys 120 operates
within the trolley track 128. Although a straight C-section is
shown as the trolley track 128, other shapes and configurations
can be employed for the device which the mobile jacking trolleys
120 travel on. Likewise, various devices can be used on the
jacking trolley 120. For example, in lieu of hydraulic cylinders
123, mechanical jacks could be employed to provide lifting forces
to the jacking beam 140.
FIGS. 24A and 24B show cross-sectional views of a portion of
the forming system 110. FIG. 24A shows a side view of the first
support beam 150A. FIG. 24B shows a side view of the second
support beam 1508. The first support beam 150A is connected to
the plurality of form sections 170. Adjacent form sections 170
(e.g.,.170A, 170B) are connected via bolts 173 at the stiffeners
172. A series of spacers 174 are placed between adjacent form
FORT-3365 33
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' 1 1
sections 170. The spacers 174 provide a space between form
sections 170 in which is inserted a nailing strip 176 for
attaching grout channel formers (not shown) to form sections 170.
The nailing strips 176 may be made from wood strips or light gage
steel tubes or other similar material. The spacers 174 also
provide flexibility, in part, between form sections 170 and allow
the form sections 170 to warp. The stiffeners 172, which are L-
shaped, have attached to their shorter leg a plurality of clamp
tubing 155. The clamp tubing 155, which can be square tubes, are
in turn attached via a plurality of bolts 151 to the support beam
150A. Thus, the first support beam 150A is attached to the
plurality of form sections 170 via the system of bolts 151 and
clamp tubing 155.
FIG. 24B shows the connecting details of the second support
beam 150B to the plurality of form sections 170. Between each
form section 170, is a clevis 154, threaded rod 151, and wing nut
152 arrangement. Because the second support beam 150B is at the
end of the forming system 110 which will be placed out of level
(i.e., raised or lowered) the clevis 154 configuration allows for
angulation of the end of the forming system 110 which resides
nearer the second support beam 150B.
FIG. 25 depicts a plan view of the forming system 110. On
the top of the form sections 170 is a casting deck 180. Residing
on the top of the casting deck 180 are a plurality of movable
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side rails 160. The side rails 160 are movable, as denoted by
directional arrow "B", so that they can match both the shape 'of
the desired warped slab 100 and the location of the jacking beam
140 below. As the perspective view in FIG. 26 shows, each side
rail 160 is L-shaped in cross section. A vertical face 163 is
connected to a horizontal base 164A and a horizontal top rail
164B. Additional vertical gussets 162 provide additional
strength to the side rail 160. The vertical faces 163 of all the
side rails 160 are perpendicular, at all points, to the casting
deck 180. Located on the base 164 are a plurality of magnets
161, such as the "EZY-STRYP" Button Magnet made by Spillman
(Spillman Inc. of Columbus, OH). The magnets 161 provide a
simple, quck and non-penetrating attachment to form sections 170.
Other types of clamping devices may clamp abutting side rail 160
sections together to form a more positive connection. Within the
space between the side rails 160 is placed a hardenable, flowable
material, such as concrete for forming into the final warped slab
100.
It should be apparent to one skilled in the art that the
form system 110, while able to make warped pavement slabs 100,
can be used just as readily make a flat (i.e., non-warped)
pavement slab 10. Similarly, the various devices, appurtenances,
methods, and pavement systems disclosed above for use with a flat
FORT-3365 35
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pavement slab 10, can readily by applied as well in making and
installing the warped pavement slab 100.
While this invention has been described in conjunction with
the specific embodiments outlined above, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, the embodiments of the
invention as set forth above are intended to be illustrative, not
limiting. Various changes may be made without departing from the
spirit and scope of the invention as defined in the following
claims.
FORT-3365 36
