Apparatus and method for supporting concrete beams, walls and the like

A completely closed and reinforced box-like structure for forming a void area in a concrete formation is constructed of a flat sheet that is scored with a plurality of parallel crease lines and features a side edge reinforcing panel. The reinforcing panel has a plurality of slots thereon. A plurality of interior and end pieces are slit scored so that they may be folded to provide interior and end support units. The support units define a plurality of spaced apart partitions having a plurality of slots and flat support surfaces thereon. The structure is assembled by initially folding the side edge reinforcing panel into a position generally normal to the flat sheet to define a longitudinal rib. The support units are then attached to the longitudinal rib by registering the slots in the partitions in interlocking relationship with corresponding slots on the rib. The support units are then rolled over to fold remaining panels of the sheet along the crease lines in wrapping relation around the support units and thus, the flat support surfaces. As a result, an enclosure with an interior chamber is defined wherein each of the support partitions substantially fills the cross-sectional area of the interior chamber and the flat support surfaces abut the enclosure. A pair of end panels cover the enclosure end openings so that the box-like structure is completely closed.

FIELD OF THE INVENTION 
The present invention relates generally to reinforced cardboard structures 
for creating voids in concrete formations, and more particularly, to a 
box-like structure capable of being assembled at a construction site and 
supporting a structural column or grade beam until the concrete dries and 
the box-like structure deteriorates, thereby creating a void in the 
concrete formation. 
BACKGROUND OF THE INVENTION 
It is commonly known in the construction industry to create spaces or voids 
in or under various types of concrete formations. For example, concrete 
formations below grade such as the structural foundation of a building 
often require a space or void between the foundation and the ground to 
accommodate expansion of the soil, thereby preventing damage to the 
foundation. Thus, it is often desirable to create a void between the 
structural floor and/or grade beams of a foundation and the underlying 
soil to accommodate upheaval of the soil. It may also be desirable to 
create a void between the walls of a foundation and the surrounding soil 
to accommodate a similar expansion of the soil below grade. In addition, 
voids can also be utilized above grade between cement floor slabs to 
reduce the amount of cement required and to make the resulting slab 
lighter. 
Another type of concrete formation that sometimes requires a void is a 
concrete pillar or column. It is often desirable to create a void in a 
pillar or column to allow room for internal plumbing, electrical conduits 
or the like within the column. By forming a void in the column, the items 
within the column are protected and the cost of making the column can be 
reduced because less concrete is required. 
Typically, these voids are created by placing a biodegradable support 
structure made of corrugated cardboard in the desired location. These 
support structures are configured to support the building structural 
components until the poured concrete is capable of holding its own weight. 
As the concrete dries, and as the cardboard eventually deteriorates, a 
void is left in the concrete formation. However, such support structures 
are typically difficult to assemble and often can only be assembled at a 
factory and transported to a construction site. 
Support structures featuring a main wrapping sheet with separate individual 
insert sections have been known. While these support structures could be 
assembled at the construction site, they provided an unsatisfactory 
compressive strength. Of the many features which in combination provided 
the overall compressive strength, FIG. 7 shows the prior art triangular 
shaped peaks that served as interior supports for the support structure 
side walls (see dashed line 54' in FIG. 7). Such triangular peaks offered 
low compressive strength and thus adversely effected the quantity of 
concrete that could be supported by the support structure. 
Another feature of the prior art structure included interior walls 
assembled from single sections of paperboard. The paperboard sections were 
folded to provide double thickness walls and single thickness walls. 
Heretofore known support structures that could be assembled on site also 
featured ends that were open. This proved undesirable as it provided the 
very ends of the support structure surfaces with little or no support. In 
addition, such an arrangement provided an additional possible entry point 
for wet concrete. This was very undesirable as when the interior cardboard 
became wet, it lost virtually all of its strength. 
Accordingly, it is an object of the present invention to provide a box-like 
structure that may be either delivered factory assembled to the 
construction site, or delivered in a "knocked-down" configuration for easy 
assembly and installation on site. 
It is another object of the present invention to provide a box-like 
structure with a high compressive strength. 
It is another object of the present invention to provide a box-like 
structure that prevents the leakage of liquid concrete into its interior. 
It is still another object of the present invention to provide a box-like 
structure that is capable of being assembled in an efficient manner. 
SUMMARY OF THE INVENTION 
In view of the above, and in accordance with the present invention, there 
is provided a method of making a reinforced box-like structure for forming 
a void area in a concrete formation. A flat sheet of corrugated cardboard 
or similar material is scored with a plurality of parallel crease lines. A 
side edge reinforcing panel is also provided. The reinforcing panel has a 
plurality of slots thereon extending generally perpendicularly relative to 
the crease lines. A plurality of interior and end support units made of 
corrugated paper are provided separate from the flat sheet and feature a 
plurality of crease lines and slit scores. The support units define a 
plurality of spaced apart partitions having a plurality of slots and flat 
support surfaces thereon. 
Each support unit is formed by folding a flat piece of material along 
parallel crease and slit score lines to define a plurality of spaced apart 
partitions with each featuring a flat support surface. The support units 
are formed so that the partitions have double-thickness walls that are 
separated by slit scoring. Also, the slots on the double-walled partitions 
are initially defined as slits extending transversely across the slit 
scoring on the flat pieces of material. Thus, the flat pieces of material 
are folded such that panel sections on each side of the slit scoring move 
into side by side relationship to define the double-walled partitions with 
flat support surfaces. The slits transverse to the slit scores are thereby 
also folded in half to form unitary insertion slots extending 
approximately one half the height of the double-walled partitions. 
The structure is assembled by initially folding the side edge reinforcing 
panel into a position generally normal to the flat sheet to define a 
longitudinal rib. The support units are then attached to the longitudinal 
rib by registering the slots in the partitions in interlocking 
relationship with corresponding slots on the rib, wherein the partitions 
extend transversely relative to said rib. The support units are then 
rolled over to fold remaining panels of the sheet along the crease lines 
in wrapping relation around the support units and thus, the flat support 
surfaces. Thus, an enclosure with an interior chamber is defined wherein 
each of the support partitions substantially fill the cross-sectional area 
of the interior chamber. In addition, the flat support surfaces abut the 
enclosure. This provides the support structure with increased strength so 
that an appropriate quantity of concrete may be supported thereby. 
After the remaining panels of the flat sheet have been wrapped around the 
support units, a locking side flap of the sheet opposite the reinforcing 
side flap is tucked adjacent the rib. In addition, the pair of end support 
units feature end panels that are folded inward to cover the ends of the 
box-like structure. Locking end flaps, positioned on each of the end 
panels, are tucked so that their end slots engage the ends of the 
longitudinal rib and the locking side flap. As a result, the box-like 
structure is completely closed so as to prevent the entry of wet cement. 
This allows the cardboard within the structure to remain dry and strong. 
The present invention provides significant advantages over other void 
forming box-like structures. The support units with flat support surfaces 
may be easily assembled and releasably attached to the longitudinal rib of 
the cardboard sheet to provide internal strength for the structure. The 
connection of the support units to the rib also allows the overall 
box-like structure to be easily formed by rolling or "wrapping" the panels 
of the sheet around the support units. Thus, the completely closed 
box-like structures can be delivered factory assembled to the construction 
site, or they can be delivered in a "knocked-down"configuration for easy 
assembly and installation on site. Mechanical fasteners are not required 
to assemble the completely closed box-like structures, which are typically 
in the form of a beam or floor structure. 
The present invention, together with further objects and advantages, will 
be best understood by reference to the following detailed description 
taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
While the present invention is susceptible of embodiment in various forms, 
there is shown in the drawings and will hereinafter be described a 
preferred embodiment of the invention with the understanding that the 
present disclosure is to be considered as setting forth an exemplification 
of the invention which is not intended to limit the invention to the 
specific embodiment illustrated. 
Referring now to the drawings, wherein like reference numerals refer to 
like parts throughout the several views, there is shown in FIG. 1 a 
reinforced box-like structure 10 for forming a void area in a concrete 
formation (not shown). Although only a single box-like structure 10 is 
shown in FIG. 1, it will be understood by those having ordinary skill in 
the art that in a typical construction site, a plurality of box-like 
structures substantially identical to the structure 10 would be placed 
underneath grade beams of a building foundation to support substantially 
the entire weight of the grade beams when the concrete is initially 
poured. 
Referring now to FIG. 2, the structure is initially formed from a 
rectangular, flat outer sheet 12, a plurality of rectangular, flat 
interior pieces 14 and a plurality of rectangular, flat end pieces 15 of a 
semi-rigid material. Preferably, the outer sheet 12, interior pieces 14 
and end pieces 15 are made of corrugated paperboard. To facilitate 
folding, the outer sheet 12 is scored with a plurality of parallel crease 
lines 16 that define three adjacent side panels 31 as well as a first 
half-side panel 33 and a second half-side panel 33'. The outer sheet 12 
also has a side edge reinforcing panel 18 with a plurality of evenly 
spaced slots 20 thereon which extend generally perpendicularly relative to 
the crease lines 16. Similarly, the flat interior and end pieces 14 and 15 
are also scored with a plurality of parallel crease lines 22 and 23 
thereon that define interior bridge panels 27 and end bridge panels 29 and 
facilitate folding. A transverse end slot 24 is also formed in a locking 
end flap 26 on each end piece 15. Transverse slits 28 are formed in each 
interior piece 14 as well as in the two end pieces 15. As will be 
discussed in more detail below, the slits 28 in the interior and end 
pieces 14 and 15 are ultimately manipulated to register with the slots 20 
in the outer sheet reinforcing panel 18. 
Interior and end pieces 14 and 15 are also provided with slit scores, 
indicated by dashed lines 25. Referring to FIG. 3, interior pieces 14 
feature inner layers 50 and outer layers 52. The slit scoring is 
accomplished by slitting the outer layers 52 along the paths indicated by 
dashed lines 25 in FIG. 2. The inner layers 50 are not slit. Slit scoring 
25 is performed upon end piece 15 in the same manner. 
As illustrated in FIGS. 4 and 5, the interior and end pieces 14 and 15 are 
folded so that panel sections 30 on each side of the slit scores 25 move 
into side by side relationship to define a plurality of double-thickness 
walls or partitions 32 and end partitions 33. The slits 28 on each slit 
score 25 are thereby also folded in half to form unitary insertion slots 
34 and 35 extending approximately one half the height of the partitions 32 
and 33. As a result, interior support units 36 and end support units 37 
are defined. Each end support unit 37 is also configured with a single end 
panel 38 which, as will become apparent, defines a pair of 
single-thickness end walls. 
As shown in FIG. 6, the slit scoring 25 allows partitions 32 (and likewise 
33) to provide a flat support surface 53. As a result, partitions 32 and 
33, and thus support units 36 and 37, are very effective at supporting 
heavy surfaces oriented in the manner indicated by dashed line 54. In 
contrast to the apparatus and method of the present invention, if slit 
scoring were not used, partitions 32 and 33 would have a profile as 
indicated in FIG. 7 at 32'. More specifically, the top portion of the 
partition would have the profile of a triangle with the apex forming the 
support surface 53'. Such an arrangement only allows a minimal load to be 
accommodated by surface 54' without the occurrence of buckling. 
To begin assembly of the interior and end support units 36 and 37 to the 
outer sheet 12, the side edge reinforcing panel 18 (FIGS. 2, 4 and 5) is 
folded into a position generally normal to the flat outer sheet 12 to 
define a longitudinal rib 40 (FIG. 8). The interior and end support units 
36 and 37 are then attached to the longitudinal rib 40 by registering the 
slots 34 and 35 into interlocking relationship with the corresponding 
slots 20 in the rib 40 (FIG. 9). Thus, the interior and end support units 
36 and 37 are secured to the rib 40 and the partitions 32 and 33 extend 
transversely relative to the rib 40. 
As will be appreciated, the slots 20 in the rib 40 have a thickness 
substantially the same as the overall thickness of the partitions 32 and 
33, and the slots 34 in the partitions 32 have a thickness substantially 
the same as the thickness of the rib 40. To facilitate registration of the 
partitions 32 and 33 with rib 40, the slots 20, 34 and 35 each have a 
chamfer region 41 on the top of each slot 20, 34 and 35. (FIGS. 4 and 5). 
After they are assembled to the rib 40, the support units 36 and 37 are 
rolled over to fold remaining panels 42 of the sheet 12 along the crease 
lines 16 in a wrapping relation (FIGS. 10-12). As will be appreciated, the 
width of each panel 42 corresponds to an associated edge of the partitions 
32 and 33. Thus, as shown in FIGS. 11 and 12, the foregoing folding or 
rolling about the crease lines 16 results in an inherently strong 
enclosure 43 with an interior chamber 44, wherein each of the support 
partitions 32 and 33 substantially fills the cross-sectional area of the 
interior chamber 44 and the support surfaces 53 of the support units abut 
the outer sheet 12 to enhance the strength of the structure 10. The outer 
sheet 12 is also provided with a locking side flap 46 opposite the 
reinforcing rib 40, which is tucked into abutting relationship with the 
rib 40 as shown in FIG. 13. 
Finally, as shown in FIGS. 13 and 14, end panels 38 are folded inward so 
that locking end flaps 26 may be inserted into the opposing end openings 
47 of the enclosure 43 with end slots 24 receiving the ends of rib 40 and 
locking side flap 46. This allows box-like structure 10 to be completely 
closed so as to eliminate the leakage of liquid concrete into its 
interior. 
Thus, an inherently strong, cellular box-like structure 10 is provided that 
can support a great deal of weight when concrete is poured thereon to 
create a void. 
Preferably, the box-like structure 10 is manufactured to ISO 9001 Standards 
and is available in a wide variety of sizes, shapes and strengths to 
accommodate the desired void-forming application. For example, the 
box-like structure is preferably available in a "standard" strength having 
approximately 1200 PSF ultimate capacity, which is approved for a maximum 
beam/wall height of 8 feet, and an "extra" strength having approximately 
2000 PSF ultimate capacity, which is approved for a maximum beam/wall 
height of 14 feet. It should be noted that an engineer's discretion may be 
substituted for the maximum beam/wall heights stated for each strength. 
The dimensions of the box-like structure itself can also vary depending on 
the particular application. For example, the standard and extra versions 
of the box-like structure 10 can have a width of 8, 9, 10 and 12 inches, 
and a height of 4, 6, 8, 10 and 12 inches. 
In a preferred form of the invention, the box-like structure 10 is covered 
with a protective coating on each exterior surface to provide temporary 
protection prior to installation of the box-like structure 10 at the 
construction site. In case of extremely wet ground conditions, it may be 
desirable to cover the box-like structure 10 with a water resistant 
membrane. For example, the box-like structure 10 can be covered with a 
polyurethane coating, preferably about 4 millimeters thick, with 
overlapping joints where required. Where fitting is required, a desired 
area can be wrapped to prevent penetration of water from wet concrete. 
Thus, a box-like structure is provided which is inherently strong and easy 
to assemble without glues or mechanical fasteners at a construction site 
or prior to delivery to the construction site. The strength of the 
corrugated paper and the orientation of the crease and slit score lines 
facilitates the unique folding action to allow quick and easy assembly of 
the partitions. The double-thickness walls of the partitions, combined 
with the flat support surfaces provided by the slit scoring, increase the 
vertical strength of the box-like structure to provide adequate support 
for a concrete formation. 
From the foregoing, it will be observed that numerous modifications and 
variations can be effected without departing from the true spirit and 
scope of the novel concept of the present invention. It will be 
appreciated that the present disclosure is intended as an exemplification 
of the invention, and is not intended to limit the invention to the 
specific embodiment illustrated. The disclosure is intended to cover by 
the appended claims all such modifications as fall within the scope of the 
claims.