U.S. patent number 3,582,035 [Application Number 04/644,529] was granted by the patent office on 1971-06-01 for concrete pan forming system.
This patent grant is currently assigned to Structural Voids, Inc.. Invention is credited to James W. Franklin, David R. Wells.
United States Patent |
3,582,035 |
Wells , et al. |
June 1, 1971 |
CONCRETE PAN FORMING SYSTEM
Abstract
A pan-forming system and accessories therefore utilizing loose
sheet components held together in operative relationship by said
accessories, in which lip members on said accessories or elements
of the accessories are engaged between adjacent sheet materials as
spacers holding said sheet components slightly spaced apart to
facilitate stripping of said forms for early reuse. Accessories are
provided for solid deck or open center support systems with the
open center units being useable for various depth pans that may be
stripped away from the set concrete without necessitating removal
of the open center supports.
Inventors: |
Wells; David R. (Westminster,
CO), Franklin; James W. (Albuquerque, NM) |
Assignee: |
Structural Voids, Inc.
(N/A)
|
Family
ID: |
24585301 |
Appl.
No.: |
04/644,529 |
Filed: |
June 8, 1967 |
Current U.S.
Class: |
249/18; 249/176;
249/194 |
Current CPC
Class: |
E04G
17/02 (20130101); E04G 11/40 (20130101) |
Current International
Class: |
E04G
11/40 (20060101); E04G 11/00 (20060101); E04G
17/02 (20060101); E04g 011/36 () |
Field of
Search: |
;249/32,31,28,129,130,26,124,122,119,176,177,219,194 ;25/118
(M)/ |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
596,334 |
|
Jan 1948 |
|
GB |
|
522,427 |
|
Apr 1955 |
|
IT |
|
Primary Examiner: Overholser; J. Spencer
Claims
We claim:
1. A forming system for use in the construction of poured concrete
structural elements having inside corners comprising panel members
disposed in intersecting planar relationships to provide a lap
joint corner, support brackets disposed inwardly of said panel
members and away from concrete being poured for contacting at least
two such intersecting panel members to hold said panels in
operative concrete excluding positions, and extension elements on
said brackets extending between panel members in otherwise butting
contact at said lap joint for maintaining a slight gap therebetween
to facilitate removal of said panel members after the concrete has
set.
2. Structure as set forth in claim 1 wherein paired inside corners
are to be formed in spaced-apart relationship not greater than one
panel width and three panel thicknesses apart.
3. Structure as set forth in claim 1 and further comprising a gap
occluding element to prevent intrusion and escape of poured
concrete into and through said gap.
4. Structure as set forth in claim 1 wherein said system is used to
provide pan forms for the creation of voids in concrete decks and
floors that are to be poured above supporting false work form
elements and wherein said panel members are inclusive of side and
top panel elements.
5. Structure as set forth in claim 4 wherein a plurality of
brackets are used with each bracket being disposed in contacting
relationship with side and top panel elements and wherein said
extensions are positioned to maintain a gap between said side and
top panels.
6. Structure as set forth in claim 5 wherein said brackets have a
standard component disposed in upright position, and further
comprising platform support elements on said standard for engaging
and holding said top panels in elevated position.
7. Structure as set forth in claim 6 wherein said extension element
is provided by a portion of said standard raised and extending
above said platform support.
8. Structure as set forth in claim 7 wherein said extension element
is extended above said platform a distance less than the thickness
of said top panels.
9. Structure as set forth in claim 4 wherein said supporting false
work form elements are of the solid deck type and wherein said
brackets are disposed in upright position above said solid deck to
hold the side and top panels of the pan forms in operative
position.
10. Structure as set forth in claim 1 wherein said panel members
are disposed to form paired inside corners with at least one panel
extending between said corners and subjected to longitudinal
compressive stress exerted by poured concrete with said
longitudinal compressive stress being transmitted to and by an end
of an intersecting panel.
11. Structure as set forth in claim 4 wherein said supporting false
work form elements are of an open center type and wherein said
brackets are disposed in upright position to extend to a side edge
of said open center false work form elements to hold the side and
top panels of the pan forms in operative position.
12. Structure as set forth in claim 11 wherein said side panels are
aligned to extend into the open center of said false work form
elements.
13. Structure as set forth in claim 11 wherein said side panels and
brackets are aligned to extend into the open center of said false
work form elements whereby said brackets and side panels may be
positioned at adjusted elevations with respect to said false work
forms.
Description
BACKGROUND OF THE INVENTION
In order to increase the span between vertical supports in concrete
construction, other inventors and engineers have previously
recognized the advantage of providing pan-forming systems for
localized reduction in the thickness of the concrete section or
floor being poured. Previous pan systems have been provided which
leave joist like elements extending in one or more directions
across the total span of the floor system being poured. A "one way"
system would provide a plurality of parallel joist structures,
while a "two way" system would provide intersecting joists to give
the underneath side of the poured floor a grid or a waffle like
appearance. Over a long period of years different pan-forming
systems have been derived to meet such user requirements. Metal,
wood and cardboard form elements have been used to obtain desirable
floor systems. At the present time greater spans between vertical
supports have become desirable for purposes of economy of
construction as well as for convenience of building use. These
factors give new impetus to the use of pan floor systems and make
it worthwhile to provide a pan form system of greater utility in
conventional and long span construction.
The utility of any pan-forming system is determined by several
factors: The cost of pan elements; the ease and cost of placement
and support; whether or not the pan elements are reusable; the
adaptability of the pan elements to provide floor systems having
pan voids of varying depth, width or length; the ease with which
the pans may be removed and whether the pan-forming system
components may be removed before the main support or shoring
elements are removed; the detail, finish or decorative pattern
provided by the pan form elements; whether or not the pan form
elements are useable for the support, placement and fastening of
reinforcing elements or utility components that are to be embedded
in the floor system; and the ability of the pan-forming system to
withstand loads imposed by poured concrete and personnel or
equipment use during construction operations.
No previously used pan-forming system has provided the best
possible answer to all requirements, and, accordingly, different
systems have been extensively used in connection with different
types of construction. Metal and fiberglass pan forms are
expensive, and the single size and shape characteristic tends to
limit design possibilities in use. Previous wood systems have
entailed an excessive labor cost for placement and removal, and it
is difficult to efficiently reuse wood elements that have been
nailed in conventional manner. Wood forms have previously been
difficult to strip without incurring some damage to form elements
or the poured concrete.
Cardboard form systems have recently attained more widespread
usage, since they are relatively easy to install, the core elements
are directly reuseable, and design variations are possible without
excessive cost. Limitations include an inadequate depth of pan for
long span and high load installations, inadequate anchors for
utility placements, and the necessity for form and shore removal
before the pans are freed for reuse.
SUMMARY OF THE INVENTION
The present invention provides brackets and accessories that may be
used together with panels of sheet material to construct pans on
either open or closed form work supports and for either "one way"
or "two way" systems. In general, the accessory items serve to hold
plywood sheet components in operative position for forming the
desired structural voids in a poured floor system. The panels and
brackets that are used may be easily stripped from set concrete,
since each accessory item provides a lip or element extending
between adjacent form panels to hold such panels slightly apart in
their assembled relationship. This panel spacing action makes it
easier to strip the panels and form components after the concrete
has been poured and set. In use of the system the gaps left by said
spaced-apart panels can, in general, be closed through use of tape
or other gap spanning elements that are easily removable when the
pan system is removed.
The brackets used in connection with open form work support systems
provide adjustment features so that they may be used on pans of
different depth. When used in connection with an open center
forming operation, components of the present pan system can be
completely stripped as soon as the concrete has set without
disturbing the open center supports and shore elements.
Accordingly, a limited number of pan-forming components can be used
to form floors at different elevations or at different locations to
complete all forming operations in less time and at less cost. The
floor can still be fully supported during a prescribed curing
period by the left in place shores without tying up the pan-forming
components.
Since the plywood panel elements used can be of different thickness
and strength, it is possible to provide the deeper pans or voids in
a structural floor that are beneficially used when high floor
loadings or long spans are desired. The installed pans are sturdy
and durable to withstand all concrete or operational loadings, and
structural reinforcing and utility installations can be directly
anchored to the plywood panel components to securely hold such
elements in place during pouring or erection operations. Many
beneficial features are derived from this combination of a plywood
panel system and metal brackets for holding said panels in desired
relationships, in which the required structural strength is
cooperatively provided by the strength of the panels themselves and
permanence of the metal bracket elements.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view illustrating "one way" joist
construction on open center soffet shoring,
FIG. 2 is a perspective view illustrating "one way" joist
construction on solid decking,
FIG. 3 is a perspective view illustrating "two way" joist
construction on open center soffet shoring,
FIG. 4 is a perspective view illustrating "two way" joist
construction on solid decking,
FIG. 5 is a perspective view in partial section showing a "one way"
rib pan with a top panel in alternate removed position,
FIG. 6 is a perspective view in partial section showing a "two way"
rib pan with a top panel in alternate removed position,
FIG. 7 is a perspective view of a line or side panel clip,
FIG. 8 is a perspective view in partial section showing a "one way"
pan or open center forming,
FIG. 9 is a perspective view in partial section showing a "two way"
pan on open center forming,
FIG. 10 is a perspective view of a spreader element support
clip,
FIG. 11 is a perspective view in partial broken section
illustrating a corner bracket for a solid deck-forming system,
FIG. 12 is a perspective view in partial broken section
illustrating a side bracket for a solid deck-forming system,
FIG. 13 is a perspective view with partial broken section
illustrating a corner bracket for use in an open center-forming
system, and
FIG. 14 is a perspective view illustrating a side bracket for use
in an open center-forming system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 through 4 illustrate use of the invention in connection
with the construction of "one way" and "two way" floor pan systems
in which pans are supported either by an open center soffet type of
forming or on a closed deck.
FIG. 1 shows a poured floor deck 21 in which longitudinal joists 22
have been provided to extend between elements providing vertical
support for the floor deck. The longitudinal joists 22 have
reinforcing elements 23 disposed in the lower portions of the
joists to increase the tension resistance of the floor system. All
of the floor slab elements are supported by form work when the
floor is being prepared and poured.
An open center soffet type of forming is used in FIG. 1, in which
soffet boards 24 provide the main longitudinal support for the
floor system. Bracing and form shores will be disposed directly
beneath the soffets 24 to hold the form work in elevated position
above the building foundation or previously poured lower floors.
The floor slab 21 has a reduced cross section in the areas between
adjacent joists 22 to reduce the overall weight and cost of the
floor. The spaced joists 22, which can be of deep section, provide
increased tension resistance for the support of the floor and for
support of the working and dead loads that will be applied as the
building is used. Where long spans are desirable between vertical
supports, the joists 22 will be of deep section, and, accordingly,
the voids between adjacent joists will likewise be of considerable
depth.
In order to form, mold and establish such voids, the applicants
provide a rib pan-forming system in which panels of plywood are
used as the pan-forming elements. The plywood may be of thickness
as necessary to support the weight and hydrostatic pressures of the
wet concrete that is to be placed as well as personnel or equipment
loadings incident to placement and pouring operations. For a "way"
or a rib pan system the main panel components include the side
panels 26 and a top panel 27 spanning the distance between the
vertical or upwardly disposed side panels 26. In order to provide
an efficient system which may be readily assembled and in which the
panel components are reuseable, any nailing of the panels 26 and 27
together is avoided. Support brackets and clips made and used in
keeping with this invention are used to hold these panel components
in their illustrated assembled relationship.
The construction features of the brackets and clips used in the
forming of an open center system, such as that of FIG. 1, are shown
in FIGS. 7, 8 and 14. Where open center forming is used in
connection with a "two way" or waffle pan design, the corner
brackets 28 as shown in FIGS. 8, 9 and 13 are used in place of or
together with the side brackets 29 as shown in FIGS. 1, 8 and
14.
Identical pan voids can be provided where a solid deck or closed
type of forming system is to be used. The longitudinal pans of a
"one way" rib pan-forming system are shown in FIG. 2. A "two way"
forming system on solid deck supports provides an interrupted
waffle pattern when the form pans of FIG. 4 are used. For these
types of forming operations, corner brackets 38 and side brackets
39 are provided to be erected above the platform provided by the
solid deck 31. In the erection of said closed form system the clips
32, as shown in FIG. 7, may be placed on the deck 31 to receive and
hold the side panels 26. The same clips 32 may also be used to
support the side panels 26 of the open center-forming system as
shown in FIGS. 1, 3, etc. The detailed construction features of the
corner and side brackets and the clips which are used to support
the plywood panels of the various forming systems are shown in
greater detail in some of the additional drawings herewith
presented.
Before reference to such drawings, however, it would be well to
note that when the panels are erected a minor gap or open space 33
will be left between adjacent panel elements. Before a floor system
is to be poured the gap 33 between the side panels 26 and top
panels 27 can be closed to prevent loss of cement or water through
said gap. Various types of adhesive tape 34 may be applied along
the edges of the positioned pans to close off such gap where a
better finish is required on the set concrete. Since the pressure
of the poured concrete is exerted against the tape in a direction
tending to increase the adhesive bond and since the gap is quite
narrow, various types of economical paper or other types may be
used to provide good results.
In the forming of a "two way" system as shown in FIGS. 3 and 4, end
panels 36 will be used to close off individual voids and to form
diaphragm elements or cross joists 37 extending between or
intersecting the longitudinal joists 22. Separate reinforcing bars
23 may be placed in all of these intersecting channels to increase
the support strength of the poured concrete slab. Since gaps 33
will also purposely occur at the joint between the end panels 36
and the top panel 27, tape 34 can likewise be applied to close off
such gaps.
As stated, these gaps between the panels making up the pan form
system are purposely provided to maintain clearance between all of
the form panels. The form system may be removed from a poured and
cured slab much easier when the panels are not joined rigidly to
each other, as by nailing, and may be even more easily removed when
the panels are spaced-apart in such manner that they won't be
brought into tight contact one with the other under the pressure
and weight exerted by the placed concrete. After the concrete has
been poured and set and the soffets or the solid deck form supports
are removed, the side panels 26 can then be easily pried loose from
the concrete for removal. Movement of the side and end panels will
also loosen the top panel so that all elements are easily freed
from the concrete. The noted ease of removal is in large measure
due to the gaps provided between all of the otherwise contacting
panel elements.
The bracket and clip components which serve to support the form
panels and to maintain the desired gap feature are shown in best
detail by the perspective drawings FIGS. 11--14. FIGS. 11 and 12
are directed to a solid deck-forming system, while FIGS. 13 and 14
illustrate components for an open center-forming system.
In FIG. 11 a corner bracket 38 is shown. The corner bracket
essentially provides an L-shaped or angle-type upright standard 41
having a foot piece 42 at its lower end adapted for engagement with
the deck components 31. The foot piece 42 preferably provided with
a plurality of holes 43 so that conventional or scaffold-type nails
44 may be engaged therein. The corner bracket 38 is provided with a
top support 46 that extends between the elements of the L-shaped
standard 41 and is preferably joined to both flanges thereof. The
top support 46 is positioned away from the upper end 47 of the
bracket 38 a distance less than the thickness of the form material
that will be used for the top panels 27. This construction provides
flange extensions 48 that continue upwardly past the edges of any
top panel positioned on the support 46. Accordingly, the flange
extensions 48 create and tend to maintain the desired gaps 33
between the side end and top panels.
One further gap preserving element is provided on the corner
brackets 38 by the tabs 49 that are struck out of one side flange.
Preferably these tabs are formed by stamping the tab from the tab
opening 51 before the angle is bent along the bend line 52. A
similar result can be obtained, however, by providing a tab 49 that
is struck from or attached to a preformed angle piece. When the tab
extends outwardly away from the bracket 38 and in the same plane as
one of the component flanges of the bracket, the tab may be
positioned between end and side panels to provide a vertical gap
33.
Line clips 32 of the type shown in FIG. 7 may be used to position
the side or end panels 26 and 36 on the deck 31. Where such clips
are used, a gap 33 will again be left between the panels and deck
element 31. Where desired, tabs of thickness corresponding to the
thickness of the clips 32 may be positioned on the bracket 38 as
continuations of the foot piece 42. These tabs would also extend
under the panel members to preserve the gap. The clip 32 shown in
FIG. 7 has a back element 53 and upstanding sides 54. Extensions of
the back may be provided with openings 56 so that the clips can be
easily nailed to the deck pieces 31 or soffet boards 24.
FIG. 12 presents details in the construction of side brackets 39
for closed center form work. It will be seen from this illustration
that the side bracket 39 has an upright strap segment 57 and a bent
foot 58 providing nail openings 49 for the reception of scaffold or
regular nails 44. An angle support element 61 is welded or
otherwise fastened to the strap 57 in position away from the top
end of the strap to provide a strap extension segment 62 extending
above the platform provided by angle support 61. The strap
extension 62 again provides a spacer which holds the top panel 27
and side panel 26 in the desired spaced-apart relation.
A corner bracket 28 for open center-type form work is shown in FIG.
13. The bracket is in most constructional details similar to the
corner bracket 38 illustrated in FIG. 11. Accordingly, the bracket
provides an L-shaped upright standard 41, a top support 46, flange
extensions 48 and tabs 49 which are struck from the material of one
of the flange sides of the angle standard. For open center form
work the corner bracket 28 is not provided with a foot piece. The
bracket can be longer and a plurality of sets of paired holes 63
are punched in the bracket 28 so that the bracket maybe raised or
lowered with respect to the soffet forms 24 to be held at the
desired elevation by application of nails through one set of paired
openings 63 directly into the soffet boards 24, as shown in FIG.
13, or through the side panels 26 and into the soffet 24 when the
form of construction shown in FIG. 8 is used. With the nails
applied, the bracket 28 will be held at desired elevation so that
the top panels 27 and end panels 26 and 36 may be applied to
complete a pan or void forming element. The plurality of paired
openings 63 make it possible to use a single set of open center
support brackets for the forming of voids that may be of varied
depth, width or length.
In the construction of either corner brackets 28 or 38 a structural
T shape may be beneficially used in place of the angle shown and
described. One-half of the T crossbar can then be extended between
side and end panels to maintain the desired gap in place of the
tabs 49.
A side bracket for an open center-forming system is shown in FIG.
14 where the bracket 39 has an upright strap element 57 with an
angle support 61 fastened thereto in position to provide the strap
extension 62. Paired openings 63 are again provided so that the
side bracket may be applied and held at different elevations as
desired. The nails 44 used to hold the open center brackets are in
general easily removed by initial prying action directed against
the strap or brackets or by hammer blows directed against a portion
of the bracket extending below the soffet forms 24. After the
brackets are initially loosened, a hammer may be used to pull the
nails, and the brackets can be completely removed. As soon as the
brackets are removed the form pieces 26, 36 and 27 can be easily
parted from the cured concrete.
The brackets 28 and 29 as used with an open center system obviously
have advantages in addition to the adaptability for use to provide
pan elements of different depth. On an open center system all the
support brackets and all the pan elements may be removed without
disturbing the soffet boards 24 or the upright supports or shores
therefor. Accordingly, on any job where roof or floor decks are to
be poured in sections or at different levels, the pan panel
elements may with this system be removed as soon as the concrete
has taken an initial set. Removed panel elements and support
brackets can, accordingly, be used for frequent pouring operations,
and the contractor is thus required to provide and use a lesser
number of pan components than would otherwise be required. The
adaptability for frequent reuse substantially reduces the overall
cost of pan components without any increase in the cost of labor
for installation and removal.
As previously mentioned, the gap separating otherwise contacting
elements of the pan system facilitates such early removal of the
pan form elements. In most building construction operations using
this system, the pan form elements of an open center installation
could usually be removed within 24 hours after the concrete has
been poured without danger of floor collapse. The main weight of
the floor slab will still be supported by the in-place and
undisturbed shores and soffets.
Form stripping operations may be further expedited where an open
center type of forming as shown in FIG. 8 is used. In this modified
system the plywood side panels 26 and end panels 36 extend
downwardly past the soffet boards 24. The corner brackets 28 and
side brackets 29 are then nailed in place by nails extending
through the panels 26 and 36. These panels may be stripped without
disturbing the soffets 24 or any clips 32. Panels of one size may
be used to form voids of various depths by allowing any excess of
panel height to extend past and below the soffet.
A different type of clip 64 is presented in FIG. 10 for use with
open center forming operations. The clip 64, as used in FIG. 8, may
be applied to the soffet boards 24 or to the surface of the panels
so that the channel segments 66 of the clip are disposed inwardly
when the extension pieces 67 are engaged against the edge of a
soffet board or panel. The channel segments can then support a
spreader board 68 that extends between the side panels 26 and up to
the level of the bottom surface of the top panel 27. This spreader
68 helps to support any long span side panels 26 or top panels
27.
FIGS. 6 and 9 illustrate preferred installation patterns for waffle
pan or "two way" forming systems. In order to facilitate the
stripping of the pan components, it is desirable that the side and
end panels be placed in the continuous series shown where each
board extends past the end of the adjacent board. With this
arrangement the tabs 49 on the brackets 28 or 38 will be in proper
position to create the vertical gaps 33. Further, once the brackets
are removed the pan upright elements can be more easily removed
when this type of overlapped relationship is used.
For uninterrupted long span designs, as shown in FIGS. 5 and 8,
corner brackets 38 can be provided in which the tabs 49 are
extended in opposite directions to obtain the arrangement of
elements as illustrated in these FIGS. With long span
installations, no difficulty is experienced in the removal of end
or side panels where this modified type of installation arrangement
is used. Necessarily, the overlapping arrangement of FIGS. 6 and 9
as described can be used for even the long span elements.
In addition to use of the invention in connection with the building
of pans for the formation of voids in concrete floor and deck
construction, the teachings of the invention are adaptable for use
in the forming of other concrete structural elements. In any poured
concrete structure that has an inside corner and in connection with
the forming of which there is a possibility that the form elements
could become trapped in the poured concrete, use of a supporting
bracket having an extension element or component extending between
otherwise contacting form panels is recommended. Where paired
inside corners are to be formed and where the corners are spaced
apart a distance corresponding to the width of a single form
element or panel, the establishment of one or more gaps is
desirable to facilitate form removal.
While the use of tape to keep concrete from escaping from the forms
is recommended, it should be noted that the system has utility
under circumstances where no tape is used and where some of the
concrete escapes through the gaps 33. In general, if the gap is of
width less than the size of the fine gravels used in the concrete
aggregate, the loss of material when the concrete is poured will be
within operational limits. Since gravel aggregates are often
considered to include all materials retained on a No. 4 screen, the
finest gravels would have a particle size of at least
three-sixteenths of an inch. The gap 33 should, accordingly, be of
this size or smaller.
For the purposes of this disclosure, the terms "gap" or "slight
gap" are used to designate an opening of size less than the size of
the fine gravels used in the concrete admixture if tape or some
other gap occluding element is not set forth. Where the gap is
bridged or occluded, wider openings may be used without departure
from the teachings of this invention. The concrete materials that
do escape into a nonoccluded gap and that are retained therein have
little strength due to the thin cross section. Accordingly, the
forms can still be removed after the concrete has set. In practice
it has been found that the use of a gap occluding element is
preferred, since the pouring operations will be cleaner and the
forms may be more readily stripped.
* * * * *