Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
A W usTABLE CONCRETB FORMWOR~ 8Y8TEM
FIELD OF THE INVENTION
This invention pertains to a novel adjustable concrete
formwork system which can be used in the manufacture of a wide
range of structurally efficient cross-sectional shaped concrete
structural elements.
BACKGROUND OF THE INVENTION
According to current construction practice, concrete
structures such as foundation grade beams, columns, suspended and
spandrel beams and concrete float structures, are cast in place
in a conventional timber or steel pan formwork system. Precast-
ing off-site is another common concrete structure manufacturing
technique.
A conventional foundation grade beam may be used to
support, for example, the exterior wall and upper structure of
a building. A grade beam is a cast in place structure reinforced
wi~th mild steel rods. A standard type grade beam may have a
standard cross-section of 8 in. width and 24 in. depth. The
span length between intermediate supports such as footings or
piles is variable but is usually anywhere from 12 to 36 ft.
The grade beam is typically cast in place in a pre-
formed elaborate timber or steel pan formwork system which is
time consuming and labour intensive to construct. A conventional
timber formwork system can only be used six or seven times before
it deteriorates to the point where it must be discarded. New
timber formwork is then erected and used. Steel pan formwork
does not deteriorate with repeated use, but is expensive and
labour intensive to install. The concrete grade beam is
reinforced throughout its length in both the upper and lower
regions with horizontally placed steel rods and vertical
stirrups.
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The grade beam sections are cast in a conventional
formwork system of timber or steel pan construction which are
assembled and erected in place, aligned, plumbed, and adequately
braced prior to placement of reinforcing steel and concrete
within the interior of the formwork. After the concrete grade
beam has been poured in place, the formwork is then dismantled
after the concrete has reached an adequate set. The formwork is
then positioned and reassembled to continue the previously poured
lo in place concrete beam section, and prepared for the next pour.
The conventional way to construct a standard timber
or steel pan formwork system, and pour a standard steel rein-
forced rectanqular cross-section grade beam has a number of
disadvantages:
1. The assembly and dismantling of the formwork is
labour and time intensive.
2. The reuse potential of the formwork materials is
limited.
3. The formwork does not efficiently adapt to heat
or steam cure methods.
4. The rectangular cross-section of a conventional
grade beam has always been the easiest shape to
form by conventional methods, but it is struc-
turally inefficient and uses more concrete than
is necessary to achieve design strength. (At
least 25% more concrete than necessary is required
in a standard 8" by 24" cross-section grade beam).
SUMMARY OF THE INVENTION
The invention is directed to a two-sided adjustable
formwork system construction comprising: (a) an elongated upper
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section being planar along one side; (b) an elongated mid-
section being planar along both sides; and (c1 an elongated
bottom section being planar along one side.
The side of the upper section and the lower section
opposite the planar sides respectively, can have an elongated
protrusion along the respective lower side of the upper section,
and the upper side of the lower section. The width of the mid-
section can be equivalent to and adjoin the widths of the
respective protrusions of the upper section and the lower
section. The upper section and the lower section can be hollow.
In one embodiment, the upper section, the mid-section and the
lower section can be reversible relative to one another.
The mid-section can be constructed of wood, and the
upper section and the lower section can be constructed of steel.
The opposing planar sides of the mid-section can be constructed
of plywood.
The plywood panels of the mid-section can be secured
to the respective lower sides of the upper section and the upper
side of the lower section by a combination of elongated angle
sections secured to the respective lower side of the upper
section, and the upper side of the lower section. Vertical
spacers can be disposed periodically along the length of the mid-
section and bolted and otherwise secured to generally equally
spaced C sections or channels which intersect the longitudinal
angle sections at right angles.
The invention is also directed to a steel reinforced
concrete grade beam formed to have an I-shaped cross-section,
said concrete grade beam being formed by pouring concrete between
a pair of forms that are planar on one side and have a central
protrusion on the other side, the forms being arranged so that
the protruding surfaces of the respective forms face one another.
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The pair of forms can be held together by snap ties.
The grade beam can have a C-shaped cross-section which is formed
by having the pair of forms face one another so that the planar
side of one form faces to the interior, and the protruding side
of the opposite form faces the interior. The grade beam can have
a rectangular cross-section which is formed by having the pair
of forms face one another so that the planar sides of each form
face one another to the interior.
One or more of the elongated upper sections and
elongated bottom sections can be reversed, relative to the other
sections, in order to form concrete beams which have a T-shaped
cross-section, a L-shaped cross-section, and a J-shaped cross-
section.
The invention is also directed to a cast-in-place or
precast concrete form comprising: (a) at least two spatially
oriented upper sleeves, with an upper web located on one side of
the two sleeves, and extending therebetween; (b) at least two
spatially oriented lower sleeves, with a lower web located on one
side of the two sleeves, and extending therebetween; and (c) at
least two members, each member connecting telescopically the
respective upper sleeve with the respective lower sleeve, said
telescoping members enabling the two upper sleeves to be raised
or lowered relative to the two lower sleeves.
An elongated strip can be positioned between the upper
planar sheet and the lower planar sheet. The lower portion of
the upper web, and the upper portion of the lower web, together
can protrude away from the upper and lower sleeves to form a
common protrusion. The upper sleeves can be elevated relative
to the lower sleeves. A web can extend between the protruding
upper and lower sheets.
A strip of wood can extend from the top of one upper
sleeve to the top of the other upper sleeve, and from the bottom
of one lower sleeve to the bottom of the other lower sleeve.
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The form can be arranged in parallel and opposed to a
second concrete form of the same configuration, the upper and
lower webs facing one another to define a cavity in which
concrete can be poured to form a concrete beam having a rectangu-
lar cross-section. The pair of opposed forms can be held
together by snap-ties.
The form can be arranged in parallel and opposed to a
second concrete form of the same configuration, the protruding
sheets facing one another to define a cavity in which concrete
can be poured to form a concrete beam having an "I" cross-
section.
The form can be arranged in parallel and opposed to a
second concrete form, the webs of the first form facing the
protruding webs of the second form to define a cavity in which
concrete can be poured to form a concrete beam having an "C"
cross-section.
DRAWINGS
In drawings which illustrate specific embodiments of
the invention, but which should not be construed as restricting
the spirit or scope of the invention in any way:
Figure 1 illustrates an end section view of the
reversible concrete formwork system adapted for pouring a
concrete beam of rectangular cross-section;
Figure la illustrates a cross-section view of a
rectangular concrete beam formed by the formwork system arrange-
ment depicted in Figure l;
Figure 2 illustrates an end section view of the
reversible concrete formwork system adapted for pouring a
concrete grade beam of an I-shaped cross-section;
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Figure 2a illustrates a cross-section view of an I-
shaped concrete beam formed by the formwork system arrangement
depicted in Figure 2;
Figure 3 illustrates an end section view of the
reversible concrete formwork system adapted for pouring a
concrete grade beam of a C-shaped cross-section;
Figure 3a illustrates a cross-section view of a C-
shaped concrete beam formed by the formwork system arrangement
depicted in Figure 3;
Figure 4 illustrates an end section view of the
reversible concrete formwork system adapted or pouring a concrete
beam of a T-shaped cross-section;
Figure 4a illustrates a cross-section view of a T-
shaped concrete beam formed by the formwork system arrangement
depicted in Figure 4.
Figure 5 illustrates an end section view of the
reversible concrete formwork system adapted for pouring a
concrete beam of a L-shaped cross-section;
Fiqure 5a illustrates a cross-section view of a L-
shaped concrete beam formed by the formwork system arrangement
depicted in Figure 5;
Figure 6 illustrates an end section view of the
reversibIe concrete formwork system adapted for pouring a
concrete beam of J-shaped cross-section;
Figure 6a illustrates a cross-section view of a J-
shaped concrete beam formed by the formwork system arrangement
depicted in Figure 6;
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Figure 7 illustrates a detailed end section view of the
reversible concrete formwork system adapted for forming a
rectangular cross-section beam;
Figure 8 illustrates an isometric view of a rectangu-
lar-shaped cross-section beam formed by facing planar sided
concrete formwork sections;
Figure 9 illustrates an end section view of the
reversible concrete formwork system with snap-ties in place to
hold the two forms in appropriate relationship for forming an I-
shaped cross-section concrete grade beam;
Figure lO illustrates an isometric view of an I-shaped
cross-section beam formed by a pair of reversible concrete forms
with protruding sides facing one another;
Figure ll illustrates an end section view of the
reversible concrete formwork system, arranged with snap-ties,
to form a concrete grade beam of C-shaped cross-section;
Figure 12 illustrates an isometric view of a C-shaped
cross-section beam formed by a pair of reversible concrete forms,
with the protruding side of one form facing the planar side of
the opposite form;
Figure 13 illustrates an isometric view of pairs of
reversible concrete forms aligned end to end, with linear panel
connectors positioned between the aligned forms;
Figure 14 illustrates an isometric view of reversible
concrete forms arranged with an outside corner connector and an
inside corner connector so as to form two corners;
Figure 15 illustrates an isometric view of reversible
forms arranged to form cornexs, and the upper and lower sections
adapted to hold two timbers, and longitudinal and cross bracing;
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Figure 16 illustrates a plan view of four reversible
forms arranged to form a concrete column or beam of square cross-
section;
Figure 16a illustrates a plan view of a square cross-
section shaped column or beam formed by the formwork arrangement
illustrated in Figure 16;
Figure 17 illustrates a plan view of four reversible
forms arranged to form a concrete column or beam of H-shaped
cross-section;
Figure 17a illustrates a plan view of an H-shaped
cross-section shaped column or beam formed by the formwork
arrangement illustrated in Figure 16:
Figure 18 illustrates a plan view of four reversible
forms arranged to form a concrete column or beam of X-shaped
cross-section;
Figure 18a illustrates a plan view of an X-shaped
cross-section shaped column or beam formed by the formwork
arrangement illustrated in Figure 16;
Figure 19 illustrates an end section view of a pair of
elongated reversible forms, adapted to form an elongated concrete
beam of C-shaped cross-section:
Figure 20 illustrates a section view of a concrete
float formed of elongated rectangular, C-shaped and T-shaped
beams, the cavities between the beams being adapted to receive
appropriate floatation material such as foamed polystyrene;
Figure 21 illustrates a pair of elongated forms adapted
to form an I-shaped concrete beam with an elongated web mid-
section;
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Figure 21a illustra~es a concrete beam of I-shaped
cross-section with an alongated mid-section formed by the pair
of reversible concrete forms illustrated in Figure 21;
Figure 22 illustrates an elongated concrete beam;
Figure 23 illustrates an end section view of a concrete
beam with a C-shaped cross-section, with elongated mid-section;
Figure 24 illustrates an end view of a conventional
timber formwork system comprising timber, walers, snap ties and
keeper wedges, for constructing a concrete beam of rectangular
cross-section;
Figure 25 illustrates an end view of a conventional
timber formwork system for constructing a rectangular cross-
section poured-in-place concrete beam of higher elevation than
the one illustrated in Figure 24;
Figure 26 illustrates an end view of an alternative
conventional timber formwork system for constructing a poured in
place concrete beam of rectangular cross-section;
Figure 27 illustrates an end view of an alternative
conventional timber formwork system for constructing a rectangu-
lar cross-section poured-in-place concrete beam of higher
elevation than the one illustrated in Figure 26;
Figure 28 illustrates an end view of an adjustable
height embodiment of the formwork system for pouring in place a
rectangular cross-section concrete beam;
Figure 29 illustrates an end view of an embodiment of
the formwork system utilized for pouring in place a concrete beam
having a "C" cross-section;
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Figure 30 illustrates an end view of an embodiment of
the adjustable formwork system, in extended orientation, for
pouring in place a concrete beam of rectangular cross-section
of greater height than the beam that is obtained by using the
form illustrated in Figure 28;
Figure 31 illustrates an end view of a pair o~ extended
height concrete forms assembled together with snap ties and
keeper plates;
Figure 32 illustrates an end view of an embodiment of
an extended height formwork, with assembled snap ties and keeper
plates, and at the right, in exploded view, an extended height
form, with an extended slider plate, the combination being
adapted to produce a cast-in-place concrete beam having an
extended height "C" cross-section:
Figue 33 illustrates an end view an assembled pair of
extended height concrete forms adapted to form a cast-in-place
concrete beam having a "C" cross-section shape;
Figure 34 illustrates an end view of an assembled
extended height formwork system adapted to form a cast-in-place
concrete beam having an "I" cross-section;
Figure 35 illustrates a side view of an extended height
form with the lower sleeve and slider and installed keeper plate;
Figures 36(a) and (b) illustrate respectively a top
section and a side view of the extension slider for the adjust-
able height formwork system;
Figure 37 illustrates a side, partial section view of
the adjustable height form showing the bottom of the extension
slider being adapted to fit with the snap-tie receiving tube;
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Figure 38 illustrates a detail end section view of the
lower portion of an adjustable form showing internal reinforce-
ments and snap-tie guide tube;
Figure 39 illustrates an end section view of the lower
portion of the adjustable form, with panel end gusset stiffener;
Figure 40 illustrates an end partial section view of
the mid-section of the extended height form, showing the
extension slider, the plywood face, and mid-elevation securing
snap-tie and keeper plate;
Figure 41 illustrates an end section view of the lower
portion of an extended height form illustrating the extension
slider, the snap-tie and receiving tube, and the protruding inner
face, adapted to form a recess in the poured-in-place concrete
beam;
Figure 42 illustrates an end partial section view of
the mid-portion of the adjustable form illustrated in Figure 41,
showing mid-section securing snap-tie, and reinforcing timber
spacer; ~
Figure 43 illustrates an embodiment of the adjustable .~.
form with keepers on the right side adapted to form a concrete
beam with an inverted "J" cross-section;
Figure 44 illustrates an embodiment of the adjustable
form with keepers on the right side adapted to form a concrete
beam with an inverted "T" cross-section; and
Figure 45 illustrates an embodiment of the adjustable
: form with keepers onithe right side adapted to form a concrete
beam with an inverted "L" cross-section. ~ -
: .
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DETAILED DESCRIPTION OF SPECIFIC
EMBODIMENTS OF THE INVENTION
The following discussion, for illustrative and best
mode purposes, relates to the forming of a concrete beam, such
as a grade beam. It will be understood that other types and
shapes of concrete structures may be formed using one of the
various embodiments of the adjustable concrete formwork system.
10Referring to the drawings, Figure 1 illustrates an end
section view of one embodiment of formwork system adapted for
pouring a concrete beam of rectangular cross-section. Figure la
illustrates a cross-section view of a rectangular beam 9 formed
by the formwork system arrangement depicted in Figure 1. As seen
15in Figure 1, the formwork system 2 is constructed basically of
a wooden mid-section 4, with a hollow steel or aluminum top-
section 6 and a hollow steel or aluminum bottom-section 8 secured
to the tops and bottoms respectively of the wood mid-section 4.
20Figure 2 illustrates an end section view of the
formwork system adapted for pouring a concrete beam of an I-
shaped cross-section. Figure 2a illustrates a cross-seation view
of an I-shaped beam 11 formed by the formwork system arrangement
depicted in Figure 2.
Figure 3 illustrates an end section view of the
formwork system adapted for pouring a concrete beam of a C-
shaped cross-section. Figure 3a illustrates a cross-section view
of a C-shaped beam 13 formed by the formwork system arrangement
30depicted in Figure 3. The formwork system illustrated in Figures
1, 2 and 3 can be used to cast the three cross-sectional shapes
shown by simply reversing the forms.
Figure 4 illustrates an end section view of one
35embodiment of the concrete formwork system adapted for pouring
a concrete beam of a T-shaped cross-section and Figure 4a illus-
trates a cross-section view of a T-shaped concrete beam 15 formed
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by the formwork system arrangement depicted in Figure 4. Figure
5 illustrates an end section view of the concrete formwork system
adapted for pouring a concrete beam of a L-shaped cross-section
and Figure 5a illustrates a cross-section view of a L-shaped
concrete beam 17 formed by the formwork system arrangement
depicted in Figure 5. Figure 6 illustrates an end section view
of the concrete formwork system adapted for pouring a concrete
beam of J-shaped cross-section and Figure 6a illustrates a cross-
section view of a J-shaped concrete beam 19 formed by the
formwork system arrangement depicted in Figure 6.
To summarize, as seen in Figures 1, 2, 3, 4, S and 6,
the six separate sections of the pair of forms 2, in each case,
can be arranged in one of six alternative patterns in order to
form respectively a rectangular cross-section beam 9, an I-
shaped concrete beam 11, a C-shaped concrete beam 13, a T-shaped
concrete beam 15, an L-shaped concrete beam 17 and a J-shaped
concrete beam 19.
~0 Clearly, while not shown in Figures 1 to 6 inclusive,
a bottom concrete retaining form will be used to hold the poured
concrete within the form, in all applications except grade beams
where the formwork is placed directly on the ground.
Referring to Figure 7, which illustrates a detailed end
cross-section view of a pair of grade beam forms 2 arranged to
form a rectangular cross-section concrete beam, the form 2 is
constructed to have a wooden mid-section 4, a hollow steel top-
section 6, and a hollow steel bottom-section 8. The mid-section
4 is constructed of a first plywood panel 10, and a second
plywood panel 12, which are bolted or screwed to four angle
sections 16, which in turn are bolted, screwed or welded to the
bottom and top surfaces respectively of the hollow top-section
6, and the hollow bottom-section 8. A conventional "2 X 4"
wooden spacer 14 is placed spatially at specified locations along
the length of the form 2, in order to provide dimensional
strength. The spacer 14 fits in upper and lower channel sections
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-. , ~ . , , : . . .,: - . .
: `
21. The advantage of this formwork construction is that it is
inexpensive to assemble, can be formed from conventional
construction materials, such as 5-ply plywood, conventional 2 X
4 timbers, and conventional angle and channel sections. The two
forms are held in place by conventional snap-ties 18 and cones
20. The snap-ties 18 and cones 20 are removed in part after the
concrete has been poured, set and the forms are removed.
The hollow steel top-section 6 and hollow steel bottom-
section 8 can be formed of conventional steel or aluminum plate,bent to assume the shape shown in Figure 7, and welded at the
meeting corner. An advantage of the hollow top-section 6 and
hollow bottom-section 8 is that hot air can be blown through the
length of the top-section 6 and bottom-section 8 in order to
accelerate the cure of the concrete, or protect it from freezing
in winter construction conditions, when the concrete is poured
in place between the two adjoining forms 2.
Figure 8 illustrates a reversible form panel cut-away
isometric view of a pair of forms 2, and a rectangular cross-
section beam 9, after it has been poured in place and cured. The
length of the pair of forms 2 can be variable as required, in
order to pour in place grade beams of specified lengths.
.
Figure 9 illustrates a detailed end section view of the
reversible version of the concrete formwork system with snap-
ties in place to hold the two forms in appropriate relationship
for forming an I-shaped cross-section concrete grade beam.
Figure 10 illustrates an isometric view of an I-shaped cross-
section beam 11 formed by a pair of reversible concrete forms
with protruding sides facing one another. Figure 11 illustrates
a detailed end section view of the reversible concrete formwork
system, arranged with snap-ties 18, to form a concrete grade beam
of C-shaped cross-section. Figure 12 illustrates an isometric
view of a C-shaped cross-section beam 13 formed by a pair of
reversible concrete forms, with the protruding side of one form
facing the planar side of the opposite form.
- . ~ ., ,.~,~. . . .
Figure 13 illustrates an isometric view of pairs of
reversible concrete forms aligned end to end, with linear panel
connectors positioned between the aligned forms. In Figure 13,
four linear panel connectors 22 are arranged so as to enable the
ends of pairs of concrete forms to be connected lengthwise in
alignment. The linear panel connectors are constructed so that
they fit inside the hollows of the hollow top sections 6 of end-
to-end arranged forms, and the hollow bottom sections 8 of the
end-to-end arranged forms. Each linear panel connector 22 is
constructed so that it has an opening 23 therein. This opening
connects with the openings in the respective forms and enables
hot air to be blown through the interior of the forms. The
linear panel connectors 22 also have abutment rims around the
circumference thereof, the abutment rims being designed to
contact the ends of the respective hollow top sections 6 and
hollow bottom sections 8 of the impinging forms.
Figure 14 illustrates an isometric view of reversible
concrete forms arranged with an outside corner connector and an
inside corner connector so as to form two corners. Figure 14
illustrates the manner in which corners can be formed utilizing
the reversible concrete formwork system of the invention.
Outside corner connectors 24 are formed using the same concepts
as the linear panel connectors 22. However, the outside corner
connector 24 is constructed so that it has a right angle
configuration. The outside corner connector 24 has appropriate
openings 23 therein to enable the hollow top sections 6 and
hollow bottom sections 8 of the abutting forms to communicate.
Figure 14 also illustrates the construction of an inside corner
connector 26. The inside corner connector 26 also has openings
23 therein, although they are not visible in Figure 14.
While not shown in specific drawings, it will be
understood that within the spirit of the invention, corner
connectors other than straight right angled corner connectors can
be utilized to construct forms of various shapes. For example,
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the corner connectors can be T-shaped, X-shaped, Y-shaped, to
enable formwork to be constructed for interior and intersecting
concrete beams and other structures. Also, the corner-connectors
need not necessarily be right angled. They can be of any angle
from virtually oo to 360D~ to accommodate various construction
requirements.
Pigure lS illustrates an isometric view of reversible
forms arranqed to form corners, and the upper and lower sections
adapted to hold two 2 X 4 timbers, and longitudinal and cross
bracing. In the formwork design illustrated in Figure 15, the
top face of the hollow top section 6 and the hollow bottom
section 8 are constructed to have respectively an upwardly
extending channel 28 and a downwardly extending channel 30,
formed in the respective top and bottom faces thereof. Upper
channel 28 and lower channel 30 are formed to accommodate 2 X 4
timbers which fit within the interior of the respective channels
28 and 30. The timbers 32 are held in place by nails driven
through a series of holes 33 drilled in the walls of the upper
channel 28 and lower channel 30.
As seen in Figure lS, timber sections 32 in the upper
channel 28 and lower channel 30 can be used to act as anchors,
to which can be fastened appropriate 2 X 4 cross-braces 34. The
timber sections 32 and 2 X 4 cross-braces 34 are nailed together
as required. In this way, the pairs of forms can be held in
place firmly, and thereby withstand the outward forces generated
by pouring concrete between the pairs of facing forms.
Figure 16 illustrates a plan view of four reversible
forms arranged to form a concrete column 38 of rectangular cross-
section. Figure 16a illustrates a plan view of a rectangular
cross-section shaped column formed by the formwork arrangement
illustrated in Figure 16. Figure 17 illustrates a plan view of
four reversible forms arranged to form a concrete column 40 of
H-shaped cross-section. Figure 17a illustrates a plan view of
an H-shaped cross-section 40 shaped column formed by the formwork
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. .: , .......... , . . : ................. . ~ ,
. . . :. . : ; ~
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arrangement illustrated in Figure 17. Figure 18 illustrates a
plan view of four reversible forms arranged to form a concrete
column 42 of X-shaped cross-section. Figure 18a illustrates a
plan view of an X-shaped cross-section shaped column 42 formed
by the formwork arrangement illustrated in Figure 18.
Figure 19 illustrates an end section view of a pair of
elongated reversible forms, adapted to form an elongated concrete
beam of C-shaped cross-section. Figure 20 illustrates a section
view of a concrete float formed of elongated rectangular 44, C-
shaped 46 and T-shaped beams, the cavities between the beams
being adapted to receive appropriate floatation material such as
foamed polystyrene 50.
Figure 21 illustrates a pair of elongated forms adapted
to form an I-shaped concrete beam with an elongated web mid-
section. Figure 21a illustrates a concrete beam of I-shaped
cross-section with an alongated mid-section formed by the pair
of reversible concrete forms illustrated in Figure 21. Figure
22 illustrates an elongated concrete beam. Figure 23 illus-
trates an end section view of a concrete beam with a C-shaped
cross-section, with elongated mid-section. This type of form
arrangement produces concrete sections of such depth and narrow
profile and are ideally suited for marine float structure
construction.
Figure 24 illustrates an end view of a conventional
timber formwork system comprising timber, walers, snap ties and
wedges, used to form a cast-in-place concrete beam of rectangular
cross-section. Figure 25 illustrates an end view of a timber
formwork system for constructing a poured-in-place concrete beam
of higher elevation than the one illustrated in Figure 24.
Figure 26 illustrates an end view of an alternative timber
formwork system for constructing a poured-in-place rectangular
cross-section concrete beam. Figure 27 illustrates an end view
of an alternative timber form system for constructing a poured-
- 17 -
in-place concrete beam of higher elevation than the one illus-
trated in Figure 26.
Referring to Figure 24 in detail, it illustrates a
conventional wooden formwork system used for pouring in place a
rectangular cross-section concrete beam. The form is labour
intensive because it involves a considerable amount of manual
labour to cut the various wooden pieces to size. A number of
separate pieces are required for a form of this construction.
The wood form comprises a pair of cut-to-size facing plywood
sheets 50, reinforced by bracing 2 X 4's 52, which are held by
lower and upper snap-ties 54, which are of conventional construc-
tion. The snap-ties 54 extend through the plywood faces 50, and
are secured by wedges 5~, which are hammer driven into place by
the form installer. The wedges 56 are braced against a pair of
walers 58 which are positioned on the top and bottom sides of the
respective snap-ties 54, the wedges 56 holding the pair of walers
58 against the rear faces of the 2 X 4 bracing 52.
Figure 25 illustrates the type of conventional wooden
formwork system that is used to form a cast-in-place rëctangular
cross-section concrete beam of elevated height. This formwork
system resembles the one shown in Figure 24 except that three
snap-ties are required, and accompanying walers 58 and wedges 56
are required.
Referring to Figure 26 in detail, it illustrates an
alternative embodiment of a conventional wooden form used for
casting in place a rectangular cross-section concrete beam in
place. This formwork system is generally cheaper than the one
illustrated in Figures 24 and 25, because fewer pieces of timber
are required. The use of a second waler 58 for each snap-tie 54
is eliminated with this type of form construction. However, more
specific shapes of metal pieces are required. For instance, a
metal piece 60, which is accompanied by one waler 58, is used in
association with each wedge 56, and snap-tie 54. In this
orientation, the 2 X 4 bracing 52 is positioned on the outside
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.. . . .
.
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- :
of the waler 58, removed from the plywood face 50. The 2 X 4
bracing s2 is secured to the waler 58 by a specially constructed
fastener 62, with locking handle 64.
Figure 27 illustrates a conventional formwork construc-
tion similar to that shown in Figure 26, except in this case, the
form is adapted for casting in place a concrete beam of height-
ened elevation rectangular cross-section. The conventional
embodiment shown in Figure 27 uses three sets of snap-ties and
lo three diffeent elevations.
Figure 28 illustrates an end view of an adjustable
height embodiment of the applicant's form adapted for pouring in
place a rectangular cross-section concrete beam. This embodiment
of the invention has the advantage that it can be lowered or
raised in height to form cast-in-place concrete beams of
specified heights. In the orientation illustrated in Figure 28,
the upper sleeve 70 and the lower sleeve 72 are in compressed
(low elevation) configuration. This configuration is used to
pour in place a concrete beam of rectangular cross-section of a
conventional height of about 16 to 20 inches. The upper sleeve
70 and the lower sleeve 72, of the pair of forms, are held
together by a pair of snap-ties 74. An upper nail strip 78
formed of wood rests on the top of upper sleeve 70. A lower
wooden nail strip 80 is secured to the bottom face of lower
sleeve 72. A plywood strip 76 seals the space between the upper
planar face 84, which is typically formed of steel plate, and
lower planar face 86, which is also typically formed of steel
plate. Upper face 84 and lower face 86 are reinforced by
respective reinforcing braces 88. The left and right forms are
held in place by a pair of snap-ties 74, which are secured at
their respective ends by keeper plates 82.
Figure 29 illustrates an alternative embodiment of the
applicant's adjustable form system as utilized for pouring in
place a concrete beam having a "C" cross-section. In the version
shown in Figure 29, the right side form has upper and lower faces
-- 19 --
so and 92, which are bent to protrude inwardly in the direction
of the opposite form. The horizontal distance between the sleeve
70 and the protruding face is termed the offset and determines
the degree of indentation in the concrete beam having a "C"
cross-section. Except for the protruding faces 90 and 92, the
basic construction of the form is similar to that described for
Figure 28.
Figure 30 illustrates a pair of facing forms, similar
to that shown in Figure 28, except that the forms are in an
extended configuration, which enables a beam of higher elevation
to be poured. As seen in Figure 30, upper sleeve 70 has been
raised on slider 98, to provide an extended elevation. Upper
sleeve 70 is telescopically arranged with slider 98, in combina-
tion with lower sleeve 72. In the lower elevation position, asillustrated in Figure 28, slider 98 is not visible. However, in
the elevated orientation, upper sleeve 70 and lower sleeve 72 are
drawn apart in telescopic fashion so as to expose slider 98. As
seen in Figure 30, a longer infill panel 94 is required to fit
the space generated by exposing slider 98. Infill panel 94 is
normally constructed of plywood, cut to size. This is the only
piece of the form that requires custom cutting. This minimizes
the labour factor in assembly of the form. All other pieces of
the form are standard. Indeed, upper sleeve 70 is an inverted
version of lower sleeve 72. Likewise, upper nail strip 78 is an
inverted version of lower nail strip 80. Figure 30 also illus-
trates the two planar lateral sections 102, which fit on the
concrete-facing side of the form, over upper sleeve 70 and lower
sleeve 72 respectively. Lateral sections 102 are normally formed
of sheet steel. Slider 98 iæ normally formed of aluminum. The
lateral sections 102 are adapted to grip strip 78 at the top and
infill panel 94 at the bottom. Lower section 102 is an inverted
version of the upper lateral section. Upper sleeve 70 and lower
sleeve 72 are normally formed of steel. A steel-aluminum sliding
action is preferred to either steel-steel, or aluminum-aluminum
sliding surfaces. In the former case, rust is a problem which
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: ~ . . . . . . -
:. . .
tends to jam the sliding action, while in the latter instance,
aluminum sliding on aluminum tends to gall and jam.
Figure 31 shows a fa~ing pair of extended height forms,
of the same design as shown in Figure 30, completely assembled.
Portions of the form are shown in partial section view. In
Figure 31, keeper plates 82 have been secured to snap-ties 74,
extending through three positions on the upper sleeve 70, infill
panel 94, and lower sleeve 72 respectively. Figure 31 illus-
trates reinforcing braces 88, which support the upper and lowerlateral sections 102, and prevent them from bending outwardly
from hydrostatic pressure generated by the poured-in-place
concrete.
The form illustrated in Figure 31 is set up for forming
a poured-in-place concrete beam of elevated rectangular cross-
section. Once the concrete has been poured in place, has been
vibrated and has set, then the exterior ends of the conventional
snap-ties, which are in the form of hexagonal bolt heads, are
twisted, which break the snap-ties adjacent the inner faces of
the facing forms. The forms can then be readily removed, leaving
the mid-regions of the snap-ties 74 in place in the interior of
the poured-in-place concrete. The removed forms can then be used
again at a new location for pouring another concrete beam of
elevated rectangular cross-section.
In the design illustrated in Figures 30 and 31, all
pieces are of standard size. The only piece of variable size is
the plywood infill panel 94. Upper sleeve 70 is an inverted form
of lower sleeve 72. Upper lateral section 102 is an inverted
form of lower lateral section 102. Upper nail strip 78 is an
inverted form of lower nail strip 80. Normally, infill panel 94
is constructed of 5-ply plywood, upper nail strip 78 and lower
nail strip 80 are formed in a planing mill of suitable wood, such
as spruce, pine, fir, or the like, upper sleeve 70 and lower
sleeve 72 and lateral sections 102 are formed of steel, and
slider 98 is formed of extruded aluminum.
- 21 -
.
Figure 32 illustrates an end view (the right form is
shown in exploded end view) of a pair of concrete forms according
to the invention, in extended elevation position. The combina-
tion of two forms illustrated in Figure 32 produce a poured-in-
place concrete beam having a "C" cross-section shape. The form
shown at the left is similar to that shown previously in Figures
30 and 31. However, the form shown at the right in Figure 31 has
a pair of inwardly projecting lateral sections 104. The inwardly
projecting "offset~ distance of lateral sections 104 corresponds
with the lateral dimension of reinforcing waler 96. Normally,
waler 96 would be constructed of a standard 2 X 4 timber piece,
which in reality measures 3-1/2 inches. Thus, it is not
necessary to cut the waler 96 to an unusual size. Waler 96 is
required for reinforcing infill panel 94, so that it does not
bend under hydrostatic pressure of the freshly cast concrete.
Except for the pair of protruding lateral sections 104, and waler
96, other components of the form shown on the right side of
Figure 32 are the same as those for the form shown on the left
side of Figure 32. Figure 32 shows the construction of the
keeper plate 82. The keeper plate has a key-hole in it. The
keeper plate 82, by using the round portion of the hole, is
placed over the end of the snap-tie 74, and is then hammered
down to force the snap-tie head into the narrower section of the
hole.
Figure 33 illustrates an end partial section view of
the pair of forms illustrated in Figure 32, in assembled
position. A cast-in-place concrete beam, formed by the combina-
tion of forms illustrated in Figure 33, has a "C" extendedelevation cross-sectional shape. As illustrated in Figure 33,
reinforcing waler 96 rests on the middle snap-tie 74. No
separate support is therefore required in order to hold waler 96
in position.
Figure 34 illustrates in end view a configuration of
a pair of adjustable forms adapted to cast a concrete beam having
- 22 -
i ' ' ` ,: ~ : ~ . . ! .
an "I" cross-section. This "I" cross-sectional shape of beam has
the advantage that less concrete is used, but greater strength
is in effect acquired, as illustrated by the data in Table 3
below. In the orientation illustrated in Figure 34, two forms
constructed to have upper and lower inwardly facing protruding
lateral sections 104, are utilized.
Figure 35 illustrates a side view of the adjustable
form illustrated in Figure 30. As illustrated in Figure 35,
slider 98 extends downwardly into lower sleeve 72. Lateral
section 102 extends to either side of lower sleeve 72. Lower
nail strip 80 is secured to the bottom portion of lateral section
102. Figure 35 also illustrates keeper plate 82, which is fitted
over the end by snap-tie 74, to secure entire assembly. While
not visible in Figure 34, there is a guide tube in lower sleeve
72 through which snap-tie 7 is threaded. This guide tube is
advantageous because it prevents the installer from wasting time
endeavouring to thread snap-tie 74 through lower sleeve 72.
Figure 35 illustrates a spacer 112 of square cross-sectional
area to secure slider components 98 such that the snap-tie end
can pass between.
Figures 36(a) and (b) illustrate top-section and side-
section views of a slider 98, which is constructed of a combina-
tion of aluminum sheet metal and timber. The timber acts as
reinforcement and is useful for enabling the installer to drive
in securing nails at convenient locations. Securing bolt 118 is
visible in Figure 36(b). Slider 98 extends into the interior of
lower sleeve 72, which is typically formed of steel sheet metal.
Timber pieces 114 and 116 can be constructed of conventional 2
X 4's. Securing bolts 118 can be placed at various elevations
along the slider 98.
Figure 37 illustrates a side, partial section view of
the form, illustrating in particular the construction of the
lower end 120 of slider 98. The lower end of slider 98 is
adapted so that it fits over and does not interfere with guide
- 23 -
:
tube llo. It will be understood that other designs can be used
so that there is no interference between the base of slider 98
and guide tube llo.
Figure 38 illustrates an end section view of the
construction of the lower sleeve 72 with a snap-tie 74 held in
place by a keeper plate 82. Reinforcing braces 88 are visible.
Also, guide tube 110 is shown. The slider 98 slides up and down
within the interior of lower sleeve 72.
Figure 34 illustrates an end view of a form construc-
tion similar to that shown in Figure 38. However, as seen in
Figure 39, a reinforcing gusset piece 100 is installed behind
lower lateral section 102. Gusset piece 102 stiffens the face
of lateral section 102, thereby preventing lateral section 102
from assuming a concave configuration due to hydrostatic pressure
of the freshly cast concrete.
Figure 40 illustrates a detailed end view of the mid-
region of the adjustable form in extended configuration. Slider
98 is secured in combination with infill panel 94 and lower
sleeve 72 and lateral section 102 by a mid elevation snap-tie 74,
held in place by a keeper plate 82 on the rear face of the slider
98.
Figure 41 shows a detailed end partial section view
of the lower region of a form with an inwardly protruding lateral
section 104. This form design is used to produce a concrete beam
having either a "C" cross-section, an "I" cross-section, a "T"
cross-section or a "J" cross-section. The lower sleeve 72, as
seen in Figure 41, is fitted with an inwardly protruding lateral
section piece 104. Infill panel 94 is fitted into the top
portion of lateral section 104. The protrusion of lateral
section 104 is strengthened by a stiffener 122, which enables the
protrusion to withstand the lateral hydrostatic forces of the
freshly cast concrete.
- 24 -
. , : t,
- ,; ~
Figure 42 illustrates a detailed side partial section
view of the mid-region of the form configuration utilized for
producing a concrete beam of "c", ~I", "T" or "J" cross-section.
Supporting waler 96, as discussed previously, is visible in
Figure 42. Waler 96 rests on snap-tie 74 and prevents infill
panel 94 from being pushed outwardly by the weight of the freshly
cast concrete. Stiffener 122 is also visible in Figure 42. The
offset distance, that is, the distance that infill panel 94
projects inwardly (to the left) in relation to slider 98, is
lo specified usually to be that of a standard "2 X 4" timber. In
this way, conventional commercially available pieces of lumber
can be used in combination with the form system of the invention.
Typically, stiffener 122, and lower sleeve 72, are formed of
steel sheet. Slider 98 is typically formed of extruded aluminum,
which assists in the sliding action that can take place between
slider 98, rubbing against the interior surface of lower sleeve
72.
Figure 43 illustrates an embodiment of the adjustable
form with an offset slider on the right side adapted to form a
concrete beam with an inverted "J" cross-section. Figure 44
illustrates an embodiment of the adjustable form offset with
sliders on both the right and left sides adapted to form a
concrete beam with an inverted "T" cross-section, and Figure 45
illustrates an embodiment of the adjustable form with an offset
slider on the right side adapted to form a concrete beam with an
inverted "L" cross-section.
The configurations illustrated in Figures 43, 44 and
45 are possible by combining selected combinations of lower
sleeves, sliders and upper sleeves. In certain configurations,
spacers 124 must be inserted in order to hold one slider 98 in
proper orientation with adjoining slider 98. The advantage is
that the basic adjustable form design can be used to form various
cross-sectional shapes of concrete beams. In the configurations
shown in Figures 43, 44 and 45, the beams can be cast directly
on the ground, thereby eliminating the need to pour footings,
before pouring the grade beam.
Example and Tables
The following is an analysis of the amount of concrete
that is required in order to pour a conventional concrete beam
or column, of the various shapes shown and disclosed herein,
utilizing the two-sided reversible beam or four-sided reversible
column formwork system.
The Reversible concrete Beam and Column Formwork System
The most significant single feature of the reversible
formwork system is ease and simplicity of set up and removal.
The panel design provides an efficient combination of superior
strength and precision of dimensionally accurate steel fabricated
sections together with the economy and versatility of timber
construction.
Longer and easier to install panels and corner sections
require far fewer support points, less bracing, less set up and
alignment time, and less stripping time than comparable conven-
tional formwork systems. By design, shape and construction, the
panel and connector system is, in fact, a modular beam in its own
right.
In addition to being a significantly more cost
effective method of casting conventional rectangular (Figure la),
square (Figure 16a) or elongated rectangular sections (Figure
22), the system readily lends itself to forming any one of five
beam and column section shapes, all of which are more structural-
ly efficient (equal to or greater design strength with less
material), while actually decreasing formwork costs and increas-
ing production levels.
- 26 -
- ~ : : - :; -
The following two Tables (Tables 1 and 2) show section
properties for various beam and column section shapes as well as
significant material and weight efficiencies associated with each
section shape in comparison to a conventional 8 inch by 24 inch
rectangular beam section shape (Figure la), and a conventional
24 inch by 24 inch square column section shape (Figure 16a).
Economies associated with material and structural
efficiencies as shown in Tables 1 and 2 apply only to the
smallest size range of beam and column sections. Naterial and
structural efficiencies and associated cost savings increase in
a manner directly proportional to any dimensional increase from
the conventional 8 inch by 24 inch rectangular light beam section
(Figure la) as shown in Table 1, or the conventional 24 inch by
24 inch square column section (Figure 16a) as shown in Table 2.
In Table 1, Beam Types of various cross-sectional
shapes with a 2 inch offset have been identified as follows:
B-l = rectangular shape shown in Figure la;
B-2 = I-cross-section shape shown in Figure 2a;
B-3 = C-cross-section shape shown in Figure 3a;
B-4 = T-cross-section shape shown in Figure 4a;
B-5 = L-cross-section shape shown in Figure 5a;
B-6 = J-cross-section shape shown in Figure 6a.
In Table 2, Column Types of various cross-sectional
shapes have been identified as follows:
C-l = square shape shown in Figure 16a;
C-2 = H-cross-section shape shown in Figure 17a;
C-3 = X-cross-section shape shown in Figure 18a.
C-4 denotes a cross-sectional column shape which is
planar on one side and notched on the other three sides. C-5
denotes a cross-sectional column shape which is planar on three
sides and notched on one side. C-6 denotes a cross-sectional
- 27 -
, . , '; . ' , ' , , ~ . : ' '
, ' ~ ' ~ ' . : . , ' ' , . :
column shape which is planar on two adjacent sides and notched
on two adjacent sides.
In Table 3, 3 and 4 (RFB-3 or RFB-4) inch offsets have
been used in calculating the physical properties of the various
depths of grade beams.
- 28 -
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a~ ~ _ _ _ _ ~ c~ ~ ~,
7 ~ o c`~i
a~ ~ u~ ~ O ~u~ _ u~.
m ~ 0 _ _ _
m ~ _ _ _ _
~1 ~
-- 29 --
.. . .
- ((
c~ :: ~ o-~ u~ ~ cui)
~D O ~D
~ ~ ~ ~ o~ o ~ cu~l
Z O N _ ~i N C) N
C~ ~ ~- _ O O O
11~ _ ~ _ ~ _
tr:
~n
~n
E~ U ~
'~ Z ¦~ E _ _
o O ~
~ _ _ r o E o CD
I
-- 30 --
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TABLE 3
NOMENCLATURE:
w = Width of Beam
L = Length of Beam
E = Modulus of Elasticity
I = Moment of Inertia
w ~D) = Dead Load
w~) = Live Load
Max y = Maximum Deflection
24 INCH DEEP BEAMS
RFB-3 CHANNEL RECTANGULAR BEAM
.,
W8 inches 8 inches
L 20 feet 20 feet
E3.5E6 psi 3.5E6 psi
I9013 inches^4 9216 inches^4
w(D)187.5 lb/ft 200 lb/ft
w(L)80 lb/ft 80 lb/ft
M~X
3.053E-2 inches 3.571E-2 inches
48 INCH DEEP BEAMS
~FB-4 CHANNEL RECTANGULAR BEAM
W8 inches 8 inchss
L 30 feet 30 feet
E3.5E6 psi 3.SE6 psi
I64568 inches^4 73728 inches^4
w(D)275 lb/ft 400 lb/ft
w(L)60 lb/ft 60 lb/ft
MAX
2.702E-2 inches 3.249E-2 inches
72 INCH DEEP BEAMS
= RFB-4 I BEAMRECTANGULAR BEAM
W 16 inches 16 inches
L 50 feet 50 feet
E 3.SE6 psi 3.SE6 psi
I 392112 inches^9 497664 inches^4
w(D) 750 lb/ft 1200 lb/ft
w(L) 500 lb/ft 500 lb/ft
1.281E-2 inches 1.373E-2 inches
- 31 -
'i
.. . .
.. . .. : . ~ : , .. - ~ .
It will be readily understood by persons skilled in the
art of concrete casting techniques and formwork systems that the
embodiments and technology disclosed and illustrated herein can
be adapted without invention to pre-cast concrete structure
manufacturing techniques, or can be used in conjunction with pre-
cast concrete manufacturing techniques.
As will be apparent to those skilled in the art in the
light of the foregoing disclosure, many alterations and modifica-
tions are possible in the practice of this invention withoutdeparting from the spirit or scope thereof. Accordingly, the
scope of the invention is to be construed in accordance with the
substance defined by the following claims.
- 32 -
