U.S. patent application number 10/638809 was filed with the patent office on 2005-02-17 for monolithic pour joint.
Invention is credited to Shaw, Lee A., Shaw, Ronald D..
Application Number | 20050036834 10/638809 |
Document ID | / |
Family ID | 34135738 |
Filed Date | 2005-02-17 |
United States Patent
Application |
20050036834 |
Kind Code |
A1 |
Shaw, Lee A. ; et
al. |
February 17, 2005 |
Monolithic pour joint
Abstract
There is provided a monolithic pour joint interposed between
adjacent concrete slabs disposed on a substrate. The pour joint
comprises a plurality of elongate forms interconnected with
splices. Each one of the forms has a substantially planar, vertical
panel with upper and lower edges and opposing ends respectively
defining a form width and a form length. The forms are arranged
such that the form lengths are generally aligned end to end. The
lower edge of the vertical panel has a base flange extending
generally laterally therefrom. A plurality of stakes are disposed
in transverse relation to the form width and are secured to a side
of the vertical panel at spaced intervals to fixedly maintain the
forms in relation to the substrate. The pour joint may include a
plurality of dowel holes extending through the vertical panel such
that a dowel placement system may be installed in the pour
joint.
Inventors: |
Shaw, Lee A.; (Newport
Beach, CA) ; Shaw, Ronald D.; (Corona Del Mar,
CA) |
Correspondence
Address: |
Kit M. Stetina, Esq.
STETINA BRUNDA GARRED & BRUCKER
Suite 250
75 Enterprise
Aliso Viejo
CA
92656
US
|
Family ID: |
34135738 |
Appl. No.: |
10/638809 |
Filed: |
August 13, 2003 |
Current U.S.
Class: |
404/47 |
Current CPC
Class: |
E01C 11/14 20130101 |
Class at
Publication: |
404/047 |
International
Class: |
E01C 011/14 |
Claims
1. A monolithic pour joint interposed between adjacent concrete
slabs disposed on a substrate, the pour joint comprising: an
elongate form having a planar, vertical panel with upper and lower
edges and opposing ends respectively defining a form width and a
form length, the lower edge having a base flange extending
generally laterally therefrom; and a plurality of elongate stakes
disposed in transverse relation to the form width and secured to a
side of the vertical panel opposite that from which the base flange
extends, the stakes being disposed at spaced intervals along the
form length; wherein the stakes are configured to fixedly maintain
the form in relation to the substrate.
2. The pour joint of claim 1 further comprising a plurality of
dowel holes extending through the vertical panel.
3. The pour joint of claim 1 further comprising: a plurality of
splices configured to be complementary to the form; and a plurality
of the forms being arranged such that the form lengths are
generally aligned end to end; wherein each one of the splices is
secured to and interconnects adjacent ones of the forms at the
lower edges thereof.
4. The pour joint of claim 1 wherein the splices are secured to the
vertical panel with mechanical fasteners.
5. The pour joint of claim 1 wherein the stakes are secured to the
vertical panel with mechanical fasteners.
6. The pour joint of claim 1 wherein the upper edge includes a
folded-over portion extending downwardly therefrom.
7. The pour joint of claim 1 further comprising a layer of
resilient joint filler disposed along a side of the vertical
panel.
8. The pour joint of claim 7 wherein the joint filler is fabricated
from foam material.
9. The pour joint of claim 1 further comprising an elongate edge
cap extending along the upper edge.
10. The pour joint of claim 9 wherein the edge cap is fabricated
from plastic material.
11. A monolithic pour joint interposed between adjacent concrete
slabs, the pour joint comprising: an elongate form having a planar,
vertical panel with upper and lower edges and opposing ends
respectively defining a form width and a form length, the upper
edge having an upper flange of inverted generally U-shaped
cross-section including a horizontal section extending laterally
from the upper edge and terminating in a downwardly extending
vertical section that is spaced apart from the vertical panel; and
a plurality of elongate stakes disposed in transverse relation to
the form width and secured to a side of the vertical panel opposite
that from which the base flange extends, the stakes being disposed
at spaced intervals along the form length, each one of the stakes
having a stake body with upper and lower ends; wherein the upper
flange is configured to receive the upper end of the stake body
such that the stakes may support the form in relation to the
substrate.
12. The pour joint of claim 11 wherein the upper flange is
configured to be resiliently flexible and is spaced away from the
vertical panel such that the upper flange may grippingly engage the
upper end of the stake body.
13. The pour joint of claim 11 wherein each of the stakes includes
at least one stake clip of generally U-shaped cross-section
extending from the stake body, the stake clip being configured to
receive the lower edge of the form.
14. The pour joint of claim 13 wherein the stake clip is configured
to be resiliently flexible such that the stake clip may grippingly
engage the lower edge.
15. The pour joint of claim 11 further comprising a plurality of
dowel holes extending through the vertical panel.
16. The pour joint of claim 11 further comprising: a plurality of
splices configured to be complementary to the form; and a plurality
of the forms being arranged such that the form lengths are
generally aligned end to end; wherein each one of the splices is
secured to and interconnects adjacent ones of the forms at the
lower edges thereof.
17. The pour joint of claim 16 wherein the splices are secured to
the vertical panel with mechanical fasteners.
18. The pour joint of claim 11 further comprising a layer of
resilient joint filler disposed along a side of the vertical
panel.
19. The pour joint of claim 18 wherein the joint filler is
fabricated from foam material.
20. The pour joint of claim 11 further comprising an elongate edge
cap extending along the upper edge.
21. The pour joint of claim 20 wherein the edge cap is fabricated
from plastic material.
22. A monolithic pour joint interposed between adjacent concrete
slabs disposed on a substrate, the pour joint comprising: an
elongate form having a planar, vertical panel with upper and lower
edges and opposing ends respectively defining a form width and a
form length, the vertical panel having a plurality of dowel holes
extending therethrough; a plurality of elongate stakes disposed in
transverse relation to the form width and secured to a side of the
vertical panel at spaced intervals along the form length and being
configured to fixedly maintain the form in relation to the
substrate; at least one sleeve mounted through one of the dowel
holes and extending laterally outwardly from the vertical panel and
into one of the concrete slabs; an elongate, tubular
dowel-receiving sheath sized and configured to be insertable into
and joinable to the sleeve; and an elongate dowel rod extending
laterally across the pour joint and being freely slidable within
the sheath embedded within one of the concrete slabs and fixedly
captured within the adjacent one of the concrete slabs.
23. The monolithic pour joint of claim 22 wherein the lower edge
has a base flange extending generally laterally therefrom.
24. The monolithic pour joint of claim 22 wherein: the sleeve
includes a sleeve flange disposed on an end thereof and having at
least one dimple disposed on an exterior of the sleeve; the sleeve
flange extending laterally outwardly from the sleeve and being
configured for mounting the sleeve to the vertical panel; the
dimple being disposed in spaced relation to the sleeve flange and
being positioned such that the vertical panel is capturable between
the sleeve flange and the dimple.
25. The monolithic pour joint of claim 24 wherein the sleeve flange
includes fastener holes spaced therearound, the fastener holes
being sized and configured to permit the passage of a fastener
therethrough for attachment of the sleeve to the vertical
panel.
26. The monolithic pour joint of claim 22 wherein the sleeve
includes a plurality of dimples disposed in spaced relation around
the exterior of the sleeve, each one of the dimples having a
wedge-shaped configuration.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] (Not Applicable)
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
[0002] (Not Applicable)
BACKGROUND OF THE INVENTION
[0003] The present invention relates generally to concrete forming
equipment and, more particularly, to a uniquely configured
monolithic pour joint specifically adapted to prevent shear
cracking of adjacently disposed concrete slabs. The pour joints are
configured to facilitate the placement of dowel rods within
adjacent concrete slabs.
[0004] During construction of concrete pavement such as for
sidewalks, driveways, roads and flooring in buildings, cracks may
occur due to uncontrolled shrinkage or contraction of the concrete.
Such cracks are the result of a slight decrease in the overall
volume of the concrete as water is lost from the concrete mixture
during curing. Typical contraction rates for concrete are about
one-sixteenth of an inch for every ten feet of length. Thus, large
cracks may develop in concrete where the overall length of the
pavement is fairly large. In addition, the cracks may continue to
develop months after the concrete is poured due to induced stresses
in the concrete.
[0005] One of the most effective ways of controlling the location
and direction of the cracks is to include longitudinal control
joints or contraction joints in the concrete. Contraction joints
are typically comprised of forms having substantially vertical
panels that are positioned above the ground or subgrade and held in
place utilizing stakes that are driven into the subgrade at spaced
intervals. The forms act to subdivide or partition the concrete
into multiple sections or slabs that allow the concrete to crack in
straight lines along the contraction joint. By including
contraction joints, the slabs may move freely away from the
contraction joint during concrete shrinkage and thus prevent random
cracking elsewhere.
[0006] In one system of concrete construction, forms are installed
above the subgrade to create a checkerboard pattern of slabs. A
first batch of wet concrete mixture is poured into alternating
slabs of the checkerboard pattern. After curing, forms may be
removed and the remaining slabs in the checkerboard pattern are
poured from a second batch of concrete. Although effective in
providing longitudinal contraction joints to prevent random
cracking, the checkerboard system of concrete pavement construction
is both labor intensive and time consuming due to the need to
remove the forms and due to the waiting period between the curing
of the first batch and the pouring of the second batch of
concrete.
[0007] In another system of concrete construction known as
monolithic pour technique, the pour joints are installed above the
subgrade in the checkerboard pattern. However, all of the slabs of
the checkerboard pattern are poured in a single pour thereby
reducing pour time as well as increasing labor productivity. An
upper edge of the forms then serves as a screed rail for striking
off or screeding the surface of the concrete so that the desired
finish or texture may be applied to the surface before the concrete
cures. The pour joints, comprised of vertically disposed forms,
remain embedded in the concrete and provide a parting plane from
which the slabs may move freely away during curing. The pour joints
additionally allowing for horizontal displacement of the slabs
caused by thermal expansion and contraction of the slabs during
normal everyday use.
[0008] Unfortunately, vertical displacement of adjacent slabs may
also occur at a joint due to settling or swelling of the substrate
below the slab or as a result of vertical loads created by
vehicular traffic passing over the slabs. The vehicular traffic as
well as the settling or swelling of the subgrade may create a
height differential between adjacent slabs. Such height
differential may result in an unwanted step or fault in a concrete
sidewalk or roadway or in flooring of a building creating a
pedestrian or vehicular hazard. Furthermore, such a step may allow
for the imposition of increased stresses on the corner of the
concrete slab at the joint resulting in degradation and spalling of
the slab. In order to limit relative vertical displacement of
adjacent slabs such that steps are prevented from forming at the
joints, a form of vertical load transfer between the slabs is
necessary.
[0009] One system for limiting relative vertical displacement and
for transferring loads between slabs is provided by key joints. In
key joint systems, the form is configured to impart a tongue and
groove shape to respective ones of adjacent slabs. Typically
preformed of steel, such a key joint imparts the tongue and groove
shape to adjacent slabs in order to allow for contraction and
expansion of the adjacent slabs while limiting the relative
vertical displacement thereof due to vertical load transfer between
the tongue and groove. The tongue of one slab is configured to
mechanically interact with the mating groove of an adjacent slab in
order to provide reactive shear forces across the joint when a
vertical load is place on one of the slabs. In this manner, the top
surfaces of the adjacent slabs are maintained at the same level
despite swelling or settling of the subgrade underneath either one
of the slabs. Additionally, edge stresses of each of the slabs are
minimized such that chipping and spalling of the slab corners may
be reduced.
[0010] Although the key joint presents several advantages regarding
its effectiveness in transferring loads between adjacent slabs, key
joints also possess certain deficiencies that detract from their
overall utility. Perhaps the most significant of these deficiencies
is that the tongue of the key joint may shear off under certain
loading conditions. Furthermore, the face of the key joint may
spall or crack above or below the groove under load. The location
of the shearing or spalling is dependent on whether the load is
applied on the tongue side of the joint or the groove side of the
joint. If the vertical load is applied on the tongue side, the
failure will occur at the bottom portion of the groove. Conversely,
if the vertical load is applied on the groove side of the joint,
the failure will occur near the upper surface of the slab upon
which the load is applied.
[0011] Shear failure of the tongue and groove may also occur due to
opening of the key joint as a result of shrinkage of the concrete
slab. As the key joint opens up over time, the groove side may
become unsupported as the tongue moves away. Vertical loading of
this unsupported concrete causes cracking and spalling parallel to
the joint. Such cracking and spalling may occur rapidly if
hard-wheeled traffic such as forklifts are moving across the joint.
Another deficiency associated with key joint systems is related to
the size, configuration and vertical placement of the tongue and
groove within the key joint. If excessively large key joints are
formed in adjacent slabs or if the tongue and groove are biased
toward an upper surface of the slabs instead of being placed at a
more preferable midheight location, spalls may occur at the key
joint. Such spalls occurring from this type of deficiency typically
run the entire length of the longitudinal key joint and are
difficult to repair.
[0012] Furthermore, key joints suffer from an additional deficiency
in that slip dowel systems may not be compatible for use with
preformed metallic key joint forms due to interference thereof with
a flanged base member of the slip dowel system. Slip dowels are
typically configured as smooth steel dowel rods that are placed
within edge portions of adjacent concrete slabs in such a manner
that the concrete slabs may slide freely along the slip dowels
thereby permitting expansion and contraction of the slabs while
simultaneously maintaining the slabs in a common plane and thus
prevent unevenness or steps from forming at the joint. Because slip
dowels are typically located near the midheight of a contraction
joint, the tongue and groove of the metal form may interfere with
the installation of the flanged base member of the slip dowel
system.
[0013] As can be seen, there exists a need in the art for a joint
system capable of minimizing relative vertical displacement of
adjacent concrete slabs caused by settling or swelling of the
subgrade or by vertical loads that may be imposed by vehicular
traffic. Furthermore, there exists a need for a joint system
capable of resisting shear failures at respective faces of adjacent
concrete slabs. Finally, there exists a need for a joint system
that is compatible with slip dowel systems such that slip dowels
may be placed within adjacent concrete slabs to aid in maintaining
the slabs in a common plane.
BRIEF SUMMARY OF THE INVENTION
[0014] The present invention specifically addresses and alleviates
the above-referenced deficiencies associated with contraction
joints of the prior art. More particularly, the present invention
is an improved, monolithic pour joint that is specifically adapted
to prevent shear cracking of adjacently disposed concrete slabs
while accommodating slip dowel systems for aiding in the placement
of slips dowels within edge portions of adjacent concrete
slabs.
[0015] The pour joint is comprised of at least one elongate form or
a plurality of forms arranged in end-to-end alignment with a splice
interconnecting the forms and a plurality of elongate stakes
secured to a side of the forms to fixedly maintain or support the
forms above the substrate. Each of the elongate forms includes a
substantially planar, vertical panel having an upper edge and a
lower edge to define a form width and opposing ends that define a
form length. The lower edge of the form has a base flange that
extends laterally from the vertical panel such that the form
defines an L-shaped configuration.
[0016] The forms, splices and stakes may be fabricated of metal
such as galvanized sheet metal. A plurality of the stakes are
secured to the vertical panel and are disposed in transverse
relation to the form width at spaced intervals along the form
length. Each one of the stakes has a stake body with an upper end
and a lower end. The upper end of the stake body is adapted to abut
against the vertical panel. The lower end of the stake body may be
provided with a point such that the stake may be driven into a
substrate of soil.
[0017] The splices are configured to interconnect adjacent ones of
the forms at the lower edges and may be secured to the vertical
panel with mechanical fasteners such as self-tapping screws. The
splices may be configured in a shape that is complementary to the
form such as in an L-shaped configuration matching the L-shaped
configuration of the form. The stakes for supporting the form may
also be secured to the vertical panel with self-tapping screws.
Additionally, the stakes may be secured to the lower edge of the
vertical panel with at least one stake clip that may be integrally
formed with and extensible from the stake body such that the form
may be rigidly held at a preset height above the substrate.
[0018] The pour joint of the present invention is configured to be
compatible with dowel placement systems due to the inclusion of
dowel holes in the forms and due to the generally planar
configuration of the vertical panel. Such dowel placement systems
may be provided at spaced intervals in the pour joints as a means
of preventing buckling or relative angular or vertical displacement
of the slabs. A sleeve of the dowel placement system may be mounted
on the form by insertion through the dowel hole. A sleeve flange of
the sleeve is abutted against and secured to the planar vertical
panel with fasteners. A sheath may be inserted into the sleeve with
steel or iron dowel rods being advanced into the sheath prior to
the pouring of concrete slabs such that the slabs may slide freely
during expansion and contraction of the slabs to maintain the slabs
in a common plane and thus prevent unevenness or steps from forming
at the pour joint.
[0019] A layer of resilient joint filler may be included along a
side of the vertical panel. The joint filler may be configured to
alternately compress and expand during relative lateral movements
of the concrete slabs such as may occur during thermal expansion
and contraction. The joint filler prevents the entrapment of
stones, debris or other material between the slabs that may
otherwise interfere with thermal expansion of the slabs. The joint
filler may be fabricated from foam material such as fiber board,
closed-cell foam rubber or low density, closed-cell polyethylene
foam. An edge cap may also be mounted upon and extend along the
upper edge of the form in order to provide protection against water
infiltration and particle entrapment within the pour joint. The
edge cap may be formed as an extrusion of relatively flexible,
elastomeric material such as a plastic material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] These as well as other features of the present invention
will become more apparent upon reference to the drawings
wherein:
[0021] FIG. 1 is a perspective view of a pour joint of the present
invention illustrating a pair of forms arranged in end-to-end
alignment with a splice interconnecting the forms;
[0022] FIG. 2 is a cross-sectional view of the pour joint taken
along line 2-2 of FIG. 1 illustrating an embodiment of the form
wherein a base flange extends laterally from a lower edge of a
vertical panel of the form and wherein the splice is configured to
be complementary to the form;
[0023] FIG. 3 is a cross-sectional view of the pour joint
illustrating the form wherein a folded-over portion extends
downwardly from an upper edge of the vertical panel;
[0024] FIG. 4 is a cross-sectional view of the pour joint
illustrating the form wherein a U-shaped upper flange extends from
the upper edge of the vertical panel with a slip dowel system being
installed therein and further illustrating the placement of the
pour joint above a subgrade using a stake;
[0025] FIG. 5 is an elevational view of the form of FIG. 4
illustrating a dowel hole extending through the vertical panel for
receiving the slip dowel system;
[0026] FIG. 6 is a cross-sectional view of the pour joint
illustrating the form wherein the upper flange in configured to be
resiliently flexible such that the upper flange may grippingly
engage the upper edge; and
[0027] FIG. 7 is an elevational view of the form of FIG. 6
illustrating stake clips secured to the lower edge of the vertical
panel.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Referring now to the drawings wherein the showings are for
purposes of illustrating preferred embodiments of the present
invention and not for purposes of limiting the same, FIG. 1
illustrates a monolithic pour joint 10 of the present invention
wherein the pour joint 10 may be interposed between concrete slabs
12 that are disposed above a subgrade or a substrate 14. The
substrate 14 may be soil underlying the slab. Alternatively, the
substrate 14 may be a metal decking or other underlying surface
adapted to support concrete slabs 12. The pour joint 10 is
comprised of at least one elongate form 16 or a plurality of forms
16 arranged in end-to-end alignment with a splice 60
interconnecting the forms 16 and a plurality of elongate stakes 48
secured to a side of the forms 16 to fixedly maintain or support
the forms 16 above the substrate 14.
[0029] Each of the forms 16 includes a substantially planar,
vertical panel 18 having an upper edge 20 and a lower edge 22 to
define a form 16 width. Each of the forms 16 also has opposing ends
24 that define a form 16 length. In one embodiment of the form 16
shown in FIGS. 1 and 2, the lower edge 22 of the form 16 has a base
flange 26 that extends laterally from the vertical panel 18 such
that the form 16 defines an L-shaped configuration. However, the
form 16 may be configured in any number of alternative
configurations wherein an upper flange 30 or a folded-over portion
28 extends from the upper edge 20 of the vertical panel 18, as will
be described in greater detail below.
[0030] The forms 16, splices 60 and stakes 48 may be fabricated of
metal such as sheet metal. The sheet metal may be a steel sheet
material. A galvanized coating on the steel sheet may be included
in order to provide maximum protection of the metal from exposure
to concrete which may other wise result in corrosion. Other
coatings for the sheet metal are contemplated and may include
powder coating and epoxy coating. In addition, the forms 16,
splices 60 and stakes 48 may be fabricated of fiber glass, carbon
fiber, Kevlar, or a polymeric material such as plastic or any
combination thereof. However, it is contemplated that the forms 16,
splices 60 and stakes 48 may be fabricated from any number of
alternative materials.
[0031] A plurality of the stakes 48 may be secured to the vertical
panel 18 in order to support the forms 16 at a preset height above
the substrate 14. The stakes 48 are disposed in transverse relation
to the form 16 width and are secured to a side of the vertical
panel 18 at spaced intervals along the form 16 length. The spacing
of the stakes 48 along the form 16 length may be adjusted based on
a number of factors including the condition of the underlying soil
and the thickness of the slabs 12. Each one of the stakes 48 has a
stake body 50 with an upper end 52 and a lower end 54. The upper
end 52 of the stake body 50 may be adapted to abut against the
vertical panel 18 as shown in FIG. 1. The lower end 54 of the stake
body 50 may be provided with a point such that the stake 48 may be
readily driven into the ground. Alternatively, the lower end 54 of
the stake body 50 may be configured with a clip such that the stake
48 may be secured to a metal decking substrate 14 as was earlier
mentioned.
[0032] It is contemplated that the pour joint 10 may be comprised
of only a single one of the forms 16 with at least one stake 48 or
a pair of the stakes 48 being secured to the vertical panel 18
adjacent to the ends 24 of the form 16 in order to support the form
16 above the substrate 14. However, the forms 16 may be arranged in
a manner similar to that shown in FIG. 1 wherein the form 16
lengths are aligned in end 24 to end 24 arrangement such that
respective ones of the ends 24 are disposed in abutting contact
wherein a plurality of the splices 60 are attached to respective
ones of the ends 24 of the forms 16. Such splices 60 are configured
to interconnect adjacent ones of the forms 16 at the lower edges 22
thereof in a manner similar to that shown in FIG. 2.
[0033] The splices 60 may be secured to the vertical panel 18 with
mechanical fasteners 62 extending through the splice 60 and into
the vertical panel 18 of the form 16 and/or into the base flange 26
of the form 16. The mechanical fasteners 62 may be self-tapping
screws or sheet metal screws as is shown in FIGS. 1, 2 and 3. Any
number of mechanical fasteners 62 may be used to secure the
adjacent form 16 lengths together such that axial and lateral loads
may be transferred across adjacent ones of the forms 16 by the
splice 60. Such axial and lateral loads may be imposed on the pour
joint 10 during assembly of the form 16 as well as during pouring
of the concrete. In addition, such axial and lateral loads may be
imposed by traffic passing over the pour joint 10 after the
concrete cures. The splices 60 may be configured in a shape that is
complementary to the form 16. As is shown in FIG. 2 the splice 60
may be formed in an L-shaped configuration matching the L-shaped
configuration of the form 16 in order to facilitate the attachment
of the splice 60 thereto. However, it is recognized herein that the
splice 60 may be configured in any number of alternate
configurations such as in a generally planar configuration in order
to facilitate the attachment of the splice 60 to the vertical panel
18 at any height between the upper edge 20 and the lower edge.
[0034] The stakes 48 for supporting the form 16 may be attached to
the vertical panel 18 with mechanical fasteners 62, as can be seen
in FIGS. 2 and 3. Such mechanical fasteners 62 may include
self-tapping screws that may be screwed through the upper end 52 of
the stake 48 and into the vertical panel 18 in order to eliminate
the need for pre-drilling of the stake 48 and the form 16.
Alternatively, the stakes 48 may be secured to the vertical panel
18 with bolts, rivets, by wiring the stake 48 to the form 16 or by
the use of a stake clip 56. The stake clip 56 may be integrally
formed with and extensible from the stake body 50, as is shown in
FIGS. 4 and 6 and as will be described in greater detail below.
Alternatively, the stake clip 56 may be a separate component (not
shown) that may be mounted on the stake body 50 and secured to the
lower edge 22 of the vertical panel 18. Regardless of the specific
manner with which the stake clip 56 is mounted, it is contemplated
that the stakes 48 may be secured to the form 16 by any number of
means such that the form 16 may be rigidly held at a preset height
above the substrate 14.
[0035] Referring now to FIGS. 1 and 4, the pour joint 10 of the
present invention is advantageously configured to be compatible
with available dowel placement systems 36 due to the inclusion of
dowel holes 64 in the forms 16. Dowel placement systems 36 are
typically provided at spaced intervals in pour joints 10 as a means
of preventing buckling or relative angular or vertical displacement
of the slabs 12. Each one of the dowel holes 64 allows for the
installation of the dowel placement system 36 which is further
facilitated by the generally planar configuration of the vertical
panel 18. As can be seen in FIG. 4, each one of the dowel placement
systems 36 may be comprised of an elongate, tubular dowel-receiving
sheath 42 that is insertable into a sleeve 38.
[0036] The sleeve 38 is mounted on the form 16 by insertion through
the dowel hole 64. The sleeve 38 may include a sleeve flange 40
that is abutted against and secured to the planar vertical panel 18
of the form 16. As is shown in FIG. 4, a plurality of dimples 44,
each of which may have a wedge-shaped configuration, are spaced
around the sleeve 38 and are configured such that forcing of the
dimples 44 through the dowel hole 64 results in the capture of the
vertical panel 18 between the sleeve flange 40 and the dimples 44,
thus maintaining the sleeve 38 in rigid attachment to the form 16.
The sheath 42 is then inserted into the sleeve 38 such that the
sleeve 38 supports the sheath 42 on the form 16.
[0037] Steel or iron reinforcing bars or dowel rods 46 may then be
advanced into the sheath 42 prior to the pouring of concrete slabs
12 such that the slabs 12 may slide freely during expansion and
contraction of the slabs 12. The dowel placement systems 36
maintain the slabs 12 in a common plane and thus prevent unevenness
or steps from forming at the pour joint 10. As is shown in FIGS. 1
and 4, the dowel holes 64 are typically located near the midheight
of the form 16 such that the sleeve flange 40 of the dowel
placement system 36 may be secured to the vertical panel 18. The
sleeve flange 40 may include fastener holes that are sized to
permit the passage of a fastener through the sleeve flange 40 in
order to facilitate the rigid attachment of the sleeve 38 to the
vertical panel 18 subsequent to the insertion of the dowel rod 46
into the sheath.
[0038] The dowel holes 64 may be sized and configured to be
complementary to the sleeve 38 of the dowel placement system 36 and
may be disposed at spaced intervals along the form 16 length
depending on the loading conditions that may be imposed upon the
slabs 12 and also depending upon the stability of the underlying
substrate 14. The longitudinal spacing of the dowel holes 64 may be
such that dowel holes 64 are provided at regularly spaced intervals
such as at six-inch spacings along the form 16 length. The dowel
placement systems 36 may be installed along the pour joint 10 at
wider spacings wherein some of the dowel holes 64 between the dowel
placement systems 36 are unused.
[0039] As is shown in FIGS. 1 and 4, the dowel holes 64 may be
located at the approximate midheight of the vertical panels 18.
However, the dowel holes 64 may be located at any other vertical
location of the vertical panel 18 such that the sleeve flange 40
may be readily secured to the vertical panel 18. Although
illustrated in FIG. 1 as through-holes, the dowel holes 64 may
alternatively be formed in the vertical panel 18 as "knockouts".
Such knockouts are generally configured as circular perforations
partially formed through the vertical panel 18 leaving an uncut
portion that allows a tab to remain with the form 16 if the tab is
bent outwardly away from the vertical panel 18. By forming the
dowel holes 64 in this manner, unused ones of the knockouts may be
bent outwardly at an angle such that they may anchor the form 16 in
the concrete slab 12 to prevent floating or rising of the form 16
in the concrete during pouring and after curing.
[0040] Referring now to FIG. 3, the form 16 may be configured such
that the upper edge 20 of the vertical panel 18 includes the
folded-over portion 28 extending downwardly therefrom. The
folded-over portion 28 may be disposed in generally abutting
contact with the vertical panel 18 along the form 16 length. The
folded-over portion 28 may be configured such that it increases the
structural rigidity or stiffness of the form 16 in order to ensure
straighter sections of the forms 16 and to resist longitudinal
bending of the form 16 during a first pour of wet concrete on one
side of the pour joint 10. Advantageously, the folded-over portion
28 may also prevent personal injury or property damage that may
otherwise result during contact with an exposed rough edge of the
form 16 at the upper edge 20. Furthermore, such folded-over portion
28 may serve as a guide rail for use with a screed for striking off
and leveling of the slabs 12 using a pair of the pour joints 10 so
as to smooth off the top surface of freshly poured concrete prior
to curing.
[0041] Referring now to FIG. 2, included with the pour joint 10 may
be a layer of resilient joint filler 66 disposed along a side of
the vertical panel 18. As can be seen, the layer of joint filler 66
has a constant thickness that spans the form 16 width and which may
also extend longitudinally along the pour joint 10 across
adjacently disposed ones of the form 16 lengths. The joint filler
66 may be configured to alternately compress and expand during
movement of the concrete slabs 12 such as may occur during thermal
expansion and contraction thereof.
[0042] In addition, the joint filler 66 may be configured to
prevent the entrapment of stones, debris or other material between
the slabs 12 that may otherwise interfere with thermal expansion of
the slabs 12. The joint filler 66 may also provide a weather tight
seal preventing excess moisture from entering the space between
adjacent ones of the slabs 12 which may otherwise lead to
freeze-thaw cracking of the concrete slabs 12. Toward this end, the
joint filler 66 may be fabricated from foam material such as fiber
board, closed-cell foam rubber or low density, closed-cell
polyethylene foam. Such foam may be pre-formed at a predetermined
thickness that is sized to be complementary to a gap between the
slabs 12. The joint filler 66 may include an adhesive layer on one
side thereof for facilitating installation to the vertical panel
18.
[0043] Referring still to FIG. 2, an elongate expansion joint cap
or edge cap 68 may also be included with the pour joint 10 wherein
the edge cap 68 may be mounted upon and extend along the upper edge
20 of the form 16 in order to provide protection against water
infiltration and particle entrapment within the pour joint 10. The
edge cap 68 may be configured with an upper portion having a
generally trapezoidal cross-sectional shape with downwardly
extending cap legs 70 that are configured to overlap exterior
surfaces of the joint filler 66 and vertical panel 18, as is shown
in FIG. 2. The trapezoidal cross-sectional shape of the upper
portion may reduce the likelihood of spalling at the pour joint 10
edge as the trapezoidal cross-sectional shape may impart a slightly
beveled edge to corners of the slabs 12. It is contemplated that
the edge cap 68 may be provided in number of alternative
cross-sectional shapes such as in a rectangular shape.
[0044] Alternatively, for pour joint 10 configurations wherein the
joint filler 66 is omitted, the edge cap 68 may be configured to be
mounted directly upon the form 16 itself with the cap legs 70 being
spaced apart at a width complementary to a thickness of the upper
edge 20 of the vertical panel 18. As mentioned above, such upper
edge 20 of the vertical panel 18 may include the folded-over
portion 28 in which case the cap legs 70 may be spaced apart at a
complementary width. The edge cap 68 may be fabricated as an
extrusion from a relatively flexible, elastomeric material such as
a plastic material. Such plastic material may be polystyrene, vinyl
or other material. However, other materials may be used to
fabricate the edge cap 68. The edge cap 68 may be bonded to the
pour joint 10 with adhesive such as a semi-rigid epoxy adhesive in
order to reduce the tendency for cracking of the slabs 12.
[0045] Referring now to FIGS. 4 and 5, shown is an alternative
embodiment of the pour joint 10 wherein the form 16 is configured
to include an upper flange 30 of inverted, generally U-shaped
cross-section on the upper edge 20 of the vertical panel 18. As can
be seen in FIG. 4, the lower edge 22 of the vertical panel 18 omits
the laterally extending base flange 26 of the earlier-described
embodiment shown in FIGS. 2 and 3. In the alternative embodiment
shown in FIG. 4, the upper flange 30 includes a horizontal section
32 that extends laterally from the upper edge 20 and terminates in
a downwardly extending vertical section 34 that is spaced apart
from the vertical panel 18. The upper flange 30 may be configured
to receive the upper end 52 of the stake body 50 as can be seen in
FIG. 5. As was earlier described, the stakes 48 are secured to the
side of the vertical panel 18 at spaced intervals along the form 16
length.
[0046] The earlier-described dowel placement system 36 is shown in
FIG. 4 as being mounted on the vertical panel 18 of the form 16 at
about the midheight of the vertical panel 18 with the sleeve 38 of
the dowel placement system 36 being secured to the vertical panel
18 with the sleeve flange 40 abutting thereagainst. The dowel rod
46 can be seen extending axially within the sheath 42 and extending
outwardly therefrom on a side of the pour joint 10 opposite the
sheath 42 such that the sheath 42 and the dowel rod 46 may be
captured within the adjacent ones of the slabs 12 after concrete is
poured on both sides of the pour joint 10. Also shown in FIG. 4 is
the joint filler 66 which generally spans the form 16 width and
which has a cutout for the sleeve flange 40. As was earlier
described, the joint filler 66 may be included with the pour joint
10 in order to fill the gap between adjacent ones of the slabs 12
and thereby prevent entrapment of debris in the gap. The
above-described edge cap 68 may also be included in the pour joint
10 as shown in FIG. 4 with such edge cap 68 being configured to be
complementary to the specific configuration of the pour joint 10.
In this regard, the cross-sectional shape and size of the edge cap
68 may be configured to be compatible with the combination of the
joint filler 66 and the form 16 or with the form 16 alone.
[0047] Referring now to FIGS. 6 and 7, the form 16 may be
configured such that the upper flange 30 includes a longitudinal
rib 58 formed within the downwardly extending vertical section 34.
As shown in FIG. 6, the rib 58 is formed such that the upper end 52
of the stake body 50 may be inserted between the upper flange 30
and the vertical panel 18. Furthermore, the upper flange 30 may be
configured to be resiliently flexible and may be spaced away from
the vertical panel 18 at the upper edge 20 such that the rib 58 of
the upper flange 30 may grippingly engage the upper end 52 of the
stake body 50. A lower portion of the upper flange 30 may be folded
outwardly at an angle of about 45 degrees such that the upper end
52 of the stake 48 may be easily inserted between the rib 58 and
the vertical panel 18.
[0048] The stake clip 56 may also be configured in a generally
U-shaped cross-section extending from the stake body 50 and
configured to receive the form 16. As shown in FIG. 6, a rib 58 may
be formed in an upwardly extending portion of the stake clip 56
such that the stake clip 56 may grippingly engage the lower edge 22
of the vertical panel 18, as is shown in FIG. 6. The stake clip 56
may be integrally formed on a side of the stake body 50 or it may
be formed on opposite sides of the stake body 50 as is shown in
FIGS. 5 and 7. The stake clip 56 may be configured to be
resiliently flexible such that rib 58 of the stake clip 56 may
grippingly engage the lower edge 22 when the form 16 is placed on
the stakes 48 subsequent to driving the stakes 48 into the
substrate 14.
[0049] Although not shown, the stake clip 56 may be configured as a
separate component that is configured to interlock the stake body
50 to the form 16. In such a configuration, the stake clip 56 may
be configured to straddle the stake body 50 and engage the lower
edge 22 of the vertical panel 18 for restraining the form 16
against the stake 48 during lateral displacement caused by pouring
of wet concrete on a side of the pour joint 10. The ribs 58 formed
in the upwardly extending portions allow the stake clip 56 to
grippingly engage the lower edge 22 of the form 16.
[0050] The operation of the pour joint 10 will now be described
with reference to FIGS. 1 through 7. The stakes 48 are initially
driven into the substrate 14 or attached to the substrate 14
depending on whether the substrate 14 is earthen (e.g., soil) or
artificial (e.g., metal decking). The stakes 48 are generally
aligned according to the desired location of the pour joint 10.
Typically, the stakes 48 are initially installed at opposite ends
24 of a predetermined length (e.g., twenty feet) after which
additional stakes 48 are then installed at intermediate positions
(e.g., at two-foot intervals). The stakes 48 are typically driven
into the substrate 14 at a depth equivalent to a desired height of
the pavement or at a desired floor elevation. If an edge cap 68 is
to be included with the pour joint 10, the stakes 48 may be driven
deeper into the substrate 14 by an amount equivalent to an
additional height of the edge cap 68.
[0051] The forms 16 are then installed on the stakes 48 with
splices 60 interconnected to opposing ends 24 of the forms 16. If
separate ones of the stake clips 56 are included, such stake clips
56 are then mounted on the stake body 50 such that the stake clips
56 engage the lower edge 22 of the vertical panel 18. If included,
a layer of joint filler 66 may be mounted against a side of the
form 16. Edge caps 68 may then be installed along the forms 16.
Dowel placement systems 36 may be installed in the forms 16 at a
desired spacing. If the dowel holes 64 are configured as knockouts,
such knockouts are first bent outwardly or removed such that the
sleeves 38 of the respective ones of the dowel placement system 36
may be installed in the dowel holes 64. Sheaths 42 are the attached
to the respective ones of the sleeves 38 and the dowels rods 46 are
then inserted into the sheaths 42. Wet concrete is then poured over
the substrate 14. Prior to curing, the concrete is leveled. A pair
of the pour joints 10 may be utilized to screed the top surface of
the slabs 12 after which a finish may be applied to the freshly
poured concrete.
[0052] Additional modifications and improvements of the present
invention may also be apparent to those of ordinary skill in the
art. Thus, the particular combination of parts described and
illustrated herein is intended to represent only certain
embodiments of the present invention, and is not intended to serve
as limitations of alternative devices within the spirit and scope
of the invention.
* * * * *