Method and apparatus for bracing elevated concrete forms

An adjustable brace for supporting an elevated concrete form floor between support beams during the curing of the concrete is provided. The adjustable brace is formed from a single leg pivotably attached to a cradle assembly for supporting half of a shoring member underneath a concrete form floor against the adjacent lower web/flange interface of a support beam. The height of the cradle assembly can be adjusted relative to the leg for raising and lowering the shoring member to enable leveling of the form floor and disassembly of the brace after the concrete has cured. In use, two braces are used to support a shoring member, with the cradle of each brace positioned between the center and an end of the shoring member and the foot of each brace positioned against the web/flange interface of the support beam opposite the support beam against which the foot of the other brace is positioned.

TECHNICAL FIELD 
The present invention relates to the construction of concrete forms for 
elevated spans. In particular, the present invention relates to adjustable 
shoring for supporting the floor of a concrete form supported between two 
support beams. 
BACKGROUND ART 
Elevated concrete spans or decks are necessary in the construction of 
bridges, multi-story buildings, and other structures such as culverts and 
falsework applications. Such spans are often constructed on site. In order 
to construct such spans, concrete forms are built between two or more 
adjacent support beams or girders. The concrete form floor can be 
constructed from corrugated metal sheets (referred to in the art as "stay 
in place" or "SIP" decking) or other materials such as plywood which are 
placed on and extend between the two adjacent support beams or girders. 
The distance between the adjacent support beams determines to a large 
extent the characteristics of the material used to construct the form 
floor. Where the distance between the adjacent support beams is relatively 
small, thinner form floor materials can be used by simply placing the form 
floor materials across the support beams. If the distance between the 
support beams is increased, and the ability of the form floor to support 
the weight of the concrete is exceeded, the builder must decide whether to 
use thicker form floor material, which is more expensive than thinner 
materials, or to use additional means for supporting the bottom of the 
form floor. 
The use of additional support for the form floor has been particularly 
desirable when using SIP decking in view of the high cost difference 
between the thin and thick SIP decking. In the past, however, the cost of 
providing the additional support necessary to be able to use thin SIP 
decking was also very high. Because each bridge, building or other 
structure is unique in many aspects, not the least of which is in the 
number of and spacing between span support beams, it has been necessary to 
construct special timber bracing for supporting a shoring timber placed 
between the span support beams for supporting the center of the form 
floor. Because the timbers for the bracing are cut to size and fitted 
depending upon the dimensions of the particular bridge, they generally 
cannot be reused. Further, a significant element of the cost of providing 
the additional support arises from the many manhours required to cut the 
timbers, construct the bracing, and disassemble when the job is completed. 
An adjustable, reusable form brace is described in my U.S. Pat. No. 
4,880,203. This form brace has two legs which are pivotally connected by a 
cradle which supports the central portion of the form deck between the two 
support beams. However, in some situations the two support beams may be 
spaced too far apart for this brace to be useful. 
Therefore, the need exists for a reusable form brace which can be used to 
support a shoring member placed beneath the form floor between the two 
support beams, which is adjustable in height to permit use in many 
different environments, and which is easy to erect and disassemble. 
SUMMARY OF THE INVENTION 
The present invention provides a reusable form brace, for providing support 
to a concrete form floor suspended between two support beams, which is 
easy to erect and disassemble. 
In one embodiment, the present invention provides a brace having a single 
leg. The leg is adjustable in length and has, at one end, a pivoting 
cradle assembly for receiving one end of a shoring member placed between 
the support beams and for adjusting the height of the shoring member 
relative to the leg, and, at its other end, a foot for holding the leg at 
the interface between the web and the lower flange of a support beam. 
In another embodiment, the present invention provides an improved elevated 
concrete form, using a plurality of the braces of the invention in 
combination with support beams and shoring members. 
In yet another embodiment, the present invention provides a method for 
bracing an elevated concrete form deck suspended between two support 
beams. 
Other and further embodiments and modifications will become apparent upon a 
review of the detailed description in conjunction with the drawings.

DETAILED DESCRIPTION 
As explained in our U.S. Pat. No. 4,880,203, which is incorporated herein 
by reference, bridges, some buildings and other elevated structures can be 
built by placing two or more substantially parallel support beams 10, 10' 
on foundation members (not shown) for the entire length of the bridge. 
Such support beams 10, 10' are typically heavy, rolled steel "I" beams or 
plate girders having an upper flange 12, a lower flange 12' and a web 14. 
A concrete form, including form floor 16, is then constructed between the 
support beams 10, 10'. Form floor 16 is typically constructed from SIP 
decking which can be left in place after the bridge is completed, or from 
plywood which can be stripped after the bridge is completed. If the 
material used to construct form floor 16 is not sufficiently strong to 
support the poured concrete without sagging or failing altogether, support 
will be needed to shore up the central region of form floor 16. In such 
event, one or more shoring timbers or members 18, are used to provide 
continuous support to the form floor 16 between the support beams 10, 10'. 
The shoring members 18 are supported in position beneath the central 
region of the elevated form floor 16 using adjustable braces of the 
present invention. 
FIGS. 1 and 2 illustrate the relationship between the support beams 10, 
10', the shoring member 18 and adjustable braces of the present invention. 
An adjustable brace of the present invention, includes a leg 20 and a 
cradle assembly 24. Leg 20 is preferably constructed from lumber available 
at the worksite, such as for example, 4 inch by 4 inch lumber, 4 inch by 6 
inch lumber, or 6 inch by 6 inch lumber, which can be rough cut to the 
approximate length desired. By using lumber available on the worksite, the 
user avoids the cost of shipping fully assembled braces to the worksite 
and need only ship a cradle assembly 24 and a foot 36 for each brace 
desired. Alternatively, leg 20 could also be constructed from a single 
piece of steel tubing; or, from two pieces of telescoping steel tubing 
which can be moved relative to each other and locked in position to permit 
rough adjustment to a desired length. Leg 20 can also be constructed from 
any other strong, load bearing material. 
As shown in FIGS. 3 and 4, the cradle assembly 24 includes a socket or cap 
26 for receiving the upper end 22 of leg 20. Cap 26 can be provided with 
holes 27, 27' for securing the leg 20 to the cap 26 using, for example, 
nails or bolts. An opening 29 is provided in the top center of cap 26 to 
permit the passage of a threaded rod 28 which preferably has a transverse 
bar 30 having a circular cross-section attached to one end. Transverse bar 
30 may be attached, for example, by welding to the end of threaded rod 28 
or by drilling a hole through the end of threaded rod 28 for receiving 
transverse bar 30 as shown in FIG. 4. 
A threaded receiver 32 is provided on the threaded rod 28 and bears against 
opening 29 on cap 26 for moving the transverse bar 30 towards cap 26 when 
the receiver 32 is rotated in one direction and away from cap 26 when 
receiver 32 is rotated in the opposite direction. A standard coil nut can 
be used for threaded receiver 32. 
The cradle assembly 24 also includes a shoring member holder 34 having two 
sleeves 33, 33' attached, for example by welding, to the bottom of holder 
34 for receiving transverse bar 30. When the transverse bar is inserted in 
the sleeves 33, 33', holder 34 should be able to freely rotate around the 
longitudinal axis of transverse bar 30 from one side of threaded rod 28 to 
the other side. This ability of the holder 34 to freely pivot about 
threaded rod 28 enables the angle between the brace and the web 14 to be 
changed simply by fixing the foot 36 at the interface between web 14 and 
lower flange 12' and moving the shoring member holder 34 along shoring 
member 18 either towards or away from support beam 10. 
The top of shoring member holder 34 is preferably formed for closely 
holding a shoring member 18, and preferably has a squared "U" shape. Such 
shoring members 18 typically range in size from about 4 inches by 4 inches 
to about 8 inches by 8 inches and can be constructed from wood, metal such 
as steel, or any other suitable load bearing material. Many variations in 
holder 34 are possible, and even a simple flat plate pivotably attached to 
the threaded rod 28 will work. Holder 34 may be provided with one or more 
holes for nailing or otherwise securing the holder 34 to the shoring 
member 18 to prevent the shoring member 18 from accidentally slipping off 
the brace. 
The bottom portion of leg 20 is preferably fitted with a foot 36, as shown 
in FIG. 3, for holding the bottom of leg 20 firmly against the interface 
between the web 14 and the lower flange 12' of support beam 10. Foot 36 
can be constructed from steel plate or other strong, load-bearing, durable 
material, and preferably includes a socket 37 for receiving the bottom end 
of leg 20 and holes 38, 38' for securing the foot 36 to the bottom end of 
leg 20 using, for example, nails or bolts. The external shape of foot 36 
may be any shape suitable for holding the brace at the interface between 
the web 14 and lower flange 12', but preferably is half-round at the 
bottom at shown in FIGS. 1 and 3 to enable the foot to pivot at the 
interface as the position of the brace relative to shoring member 18 is 
changed. 
As shown in FIGS. 1 and 2, the braces of the present invention can be used 
in pairs, with one brace supporting each half of shoring member 18. As 
liquid concrete is poured into the elevated form, the weight of the 
concrete produces pressure on the shoring member 18. This pressure is 
transferred by compression from the shoring member 16 through the shoring 
member holder 34, through the leg 20 and foot 36 of each brace to the 
support beam 10 at the interface between the web 14 and lower flange 12'. 
In wide bridges, the distance between the support beams 10, 10' may be 
sufficiently great that the angle between the web 14 and the leg 20 will 
be undesirably large if the shoring member holders 34, 34' abut each other 
at the center of shoring member 18. In order to obtain a smaller angle 
.alpha., the shoring member holders 34, 34' can be separated by a 
compression member or spacer 40 attached to the center of the shoring 
member 18, to resist the horizontal force component. Compression spacer 40 
can be constructed from any strong, load bearing material such as, for 
example, steel plate or timber. A butt plate 44 is preferably provided at 
one end of shoring member holder 34 for abutting compression spacer 40. 
Optimally, one skilled in the art will define the angle .alpha. to 
minimize the size of the shoring member 18, and possibly the size of leg 
20 as well. 
Adjustable braces of the present invention would preferably be assembled 
and used as follows. If leg 20 is made from wood or other solid material, 
a clearance bore 42 is provided for the threaded rod 28 in the top of leg 
20. The clearance bore 42 should be of sufficient size to accomodate the 
entire length of threaded rod 28. A cradle assembly 24 can then be fitted 
and attached to the top of leg 20, with the top of leg 20 fitted into cap 
26 and the threaded rod 28 being slid into clearance bore 42, and nails 
being driven through holes 27, 27' into leg 20. A foot 36 is fitted and 
attached to the bottom of leg 20. The distance between the support beams 
10, 10' is determined and, if desired, a spacer 40 is attached along the 
bottom center of a shoring member 18. The shoring member holder 34 of one 
brace is fitted onto the bottom of shoring member 18 with the butt plate 
44 abutting one end of spacer 40, and is fastened in place, for example by 
driving nails through holes 35. The shoring member holder 34' of another 
brace is fitted onto the bottom of shoring member 18 with the butt plate 
44' abutting the other end of spacer 40, and is fastened in place, for 
example by driving nails through holes 35'. If a spacer 40 is not used, 
the shoring member holders 34, 34' are attached to the center of the 
shoring member 18 so that the butt plates 44, 44' abut each other. Then 
the shoring member with attached braces is lowered into place between the 
support beams 10, 10', for example by using a crane. Workmen place the 
foot 36 of the first brace at the junction between the web 14 and the 
lower flange 12' of the first support beam and the foot 36' of the second 
brace is placed at the junction between the web 14' and the lower flange 
12"' of the second support beam 10' so that the two braces and the 
attached shoring member 18 are substantially planar with each other and 
substantially perpendicular to the facing web surfaces 14, 14' of the 
support beams 10, 10'. The height of the top surface of shoring member 18 
can then be raised or lowered as desired by rotating the threaded receiver 
32 on the threaded rod 28 of each brace. Rotation of the threaded receiver 
32 in one direction will increase the distance between the leg 20 and the 
shoring member holder 34, while rotation in the opposite direction will 
decrease the distance between the leg 20 and the shoring member holder 34. 
Finally, wedges are preferably placed between the ends of the shoring 
member 18 and the webs 14, 14' to reduce the distance between the ends of 
the shoring member 18 and the webs 14, 14' and to correspondingly limit 
movement of the shoring member 18 in the direction perpendicular to the 
webs 14, 14'. This process is repeated at intervals along the entire 
length of the span. 
Once the shoring members are in place, the concrete form superstructure can 
be constructed on top of the shoring members, final leveling, if any, can 
be performed, and the concrete poured. Disassembly after cure is 
accomplished by rotating the threaded receiver 32 of each brace to 
decrease the distance between leg 20 and shoring member holder 34, moving 
the shoring member 18 with attached braces away from the bottom of the 
form floor 16, allowing removal. 
The present invention enables the user to fully support the elevated form 
floor 16 while making any necessary adjustments to insure that the form 
floor 16 will be properly leveled as well as properly supported. 
The invention may be further understood from a consideration of the 
following theoretical example. It should be understood, however, that this 
example is merely an illustration and is not intended in any way to limit 
the scope of the claims. 
EXAMPLE 1 
An adjustable brace of the present invention as shown in FIGS. 1-4 can be 
constructed from the following materials: 
The cap 26 of the cradle assembly can be formed from 3/16 inch thick square 
steel tubing having the dimensions 4".times.4".times.1'0". Across the top 
of cap 26 is welded a 5/8" thick steel plate to close off the opening in 
the top of cap 26. Several 3/16" holes can be drilled through the side 
walls of cap 26 for securing the upper end of the leg 20 within the cap 26 
by nailing. The plate closing the top of cap 26 is provided with a 1 5/16" 
centered opening. 
A shoring member holder 34 is formed by welding two 
1/4".times.4".times.0'6" plates to one 5/8".times.53/4".times.0'6" base 
plate such that the two smaller plates form the upstanding portions of the 
"U" shaped holder as shown in FIG. 4. Threaded rod 28 is a 11/4" diameter, 
1'4" length of Dayton-Superior, B-12 continuous coil threaded rod 75M. A 
transverse bar 30 can be formed from a 4" length of 11/4" diameter steel 
rod, which is welded to one end of threaded rod 28. Transverse bar 30 is 
attached to the bottom of shoring member holder 34 by means of two 1/4" 
thick, 3/4" wide steel sleeves 33, 33' having a 1 5/16" diameter opening 
which are centered on and welded to the bottom of the "U" shaped holder 34 
so as to permit rotation of transverse bar 30 inside the sleeves 33, 33'. 
A Dayton-Superior B-13 standard 11/4" coil nut is threaded from the other 
end of the threaded rod 28 and rotated up close to the bottom of the 
shoring member holder 34 before the threaded rod 28 is inserted into the 1 
5/16" hole in the cap 26. 
A foot 36 can be constructed using 3/16" thick 4".times.4" square steel 
tubing. The top of each foot is left open to receive the bottom portion of 
the leg 20, while a piece of 1/4" steel plate curved to form a rounded "U" 
shape, as shown in FIG. 3, is used to close off the bottom end of the foot 
and adapt the foot to fit at the intersection of the web 14 and the lower 
flange 12' and to permit the foot to rotate or pivot at the intersection 
angle .alpha. between the web 14 and the leg 20 changes (e.g., if the 
position of the shoring member holder 34 along the shoring member 18 is 
changed). 
A leg can be constructed from 4".times.4" lumber. The lumber should be 
provided with a clearance bore at one end of sufficient size and length to 
accomodate the threaded rod 28. For example, a centered bore about 1 5/16" 
in diameter and about 15" deep, aligned with the longitudinal axis of leg 
20, should be sufficient. The other end of the timber can be cut to the 
approximate desired length of the leg 20, which, as will be recognized by 
one skilled in the art, will be a function of the height of the shoring 
member 18 above the lower flanges 12', 12"' of the support beams 10, 10', 
the distance between the webs 14, 14' of the support beams 10, 10' and the 
desired angle .alpha. between each leg 20 and web 14. Thus, for example, 
if the distance between the lower flange 12' and the shoring member 18 is 
about 5 feet (the "height"), and if the support beams 10, 10' are spaced 
apart about 10 feet, and if an angle .alpha. of about 40 degrees between 
the web 14 and the leg 20 is selected, one could calculate the approximate 
desired length of the leg 20 by simply dividing 5 (the height of the web) 
by the cosine of 40 degrees (.alpha.), which is approximately 6.5 feet. 
The leg would, of course, need to be cut somewhat shorter than this to 
account for the length added by the foot and the cradle assembly. 
Once the length of the leg is known, the position of the shoring member 
holder 34 on the shoring member 18 can also be easily determined, as can 
the need for and approximate length of a spacer 40. In the situation 
above, the center of the shoring member holder 34 will be optimally 
located on the shoring member 18 approximately 4.15 feet from the web 
(calculated by taking the square root of (6.5).sup.2 -(5).sup.2). Because 
the mid-point of the shoring member 18 is approximately 5 feet from the 
web, a spacer 40 will be required. Assuming a substantially level span, a 
compression spacer of about 0'2".times.0'6".times.1.7' centered on the 
shoring member between the two braces would suffice. 
To construct the brace, the threaded rod 28 would be slid into clearance 
bore 42 and the upper end of the leg would be placed into cap 26 and 
secured in place using nails driven through the 3/16" holes 27. The foot 
36 would be fitted over the lower end of the leg 20 and secured in place 
using nails driven through 3/16" holes 38. 
The spacer 40 would then be centered on and attached to the bottom surface 
of, for example, a 6".times.6".times.9'0' shoring member 18, and a brace 
would be attached to the shoring member 18 abutting each end of the spacer 
40, by placing one end of shoring member 18 in the "U" shaped shoring 
member holder 34 and sliding shoring member holder 34 along the shoring 
member 18 until it abuts the end of spacer 40 and then securing the 
shoring member holder in position by nails driven through holes 35; the 
other end of shoring member 18 would be placed in the "U" shaped shoring 
member holder 34' of a second brace, and the shoring member holder 34' 
slid along the shoring member 18 toward the spacer 40 until holder 34' 
abuts spacer 40, as shown in FIG. 1. This second brace is then secured in 
position by nails driven through holes 35'. The shoring member 18 with the 
two attached braces would then be raised into position using a crane, 
positioned between the two support beams 10, 10' and adjusted as described 
above. This is repeated at intervals along the support beams 10, 10' using 
shoring members 18', 18" as shown in FIG. 2. The concrete form can then be 
constructed on top of the shoring members 18, 18', 18". 
While the preferred embodiments have been described in detail and shown in 
the accompanying drawings, it will be evident various further 
modifications are possible without departing from the scope of the 
invention as embodied in the claims.