CA2038152A1 - Hollow core concrete building panel - Google Patents

Abstract

HOLLOW CORE CONCRETE BUILDING PANEL

ABSTRACT: The present invention provides a highly flexible building panel design and low cost manufacturing process that enables the connection of two separately finished skins (12A &
12B) with a solid cementitious bond (14 & 16) while creating a hollow core area (18) between said skins. The lightweight panel (10) contains internal formwork (15) for the structural columns (33) and beam (34) which are cast in situ after said panel has been placed. In addition, said hollow core area may be left hollow, partially filled or totally filled with various types of insulating materials as may be desired for a particular application.
Due to the high quality finish of both skins, the panel offers significant cost savings in each of its numerous applications. Furthermore, because of the flexibility of the hollow core area, the panel may be customized for different structural or insulating applications. The panel may be used for structural or non structural purposes, for wall, floor and roof panels and for non-building purposes such as noise barriers, fence walls and retaining walls.

Description

2~3~ ~2 PATENT APPLICATION OF
KENNETH R. K~IZINGER
FO~
HOLLOW COR~ CONC~ETE BUILDING PANEL

BACKGROUND OF TH~ INV~NTION
FIELD OF INVENTION
This invention relates to hollow core concrete building panels to be utili~ed as walls, ceilings, floors, roofs, column~
and the like, and specifically to improved methods of manufacturing, installing and providing the load bearing qualities for said panels.

DESCRIPTION OF PRIO~ ART
The desirability of hollow core concrete building panels is well known. The lighter weight enables construction o$ larger panels, lower transportation costs and smaller handling equipment.
Furthermore, the hollow core area i~ ideal for insulating materials as well as a way to decrease the amount oY concrete necessary for a structurally sound panel.
There are basically two types oY hollow core concrete panels i`n use and distinguished by the manufacturing process and the type of connection between the two skins. The first type of panel has a concrete connection between the Ykins and are monolithically cast using special formwork to create the hollow core area. The second type of panel con~ists of two, separately caqt skins, which .

t ' : ' , :, . ' .~ .
; ` ~
., 2 ~ 3 8 ~

are connected by an elaborate wire or metal structure to facilitate the creation of the hollow core area.
These existing hollow core concrete panels have a variety of limitations that adversely affect their cost, fini~hed appearance and flexibility. For eY,ample, the monolithically cast panels allow for only a single side to be horizontalLy cast in a form liner mold which leaves the second face roughl,y finished and in need of additional work. Furthermore, to create the hollow core area for the monolithic panel, the manufacturing process requires extensive internal forms, which are either left in place or provided by expensive and cumbersome equipment, both of' which increases the panel's co~t.
Those hollow core panels composed of ~eparately cast skins are held together by extensive fabricated wire or metal structures that substantially add to the co~t. ~ue to the weight of the individual skins and the tenuous connections, these panels are prone to shifting unless they are welded, have additional supports and an over abundance of wire is used. Furthermore, one variation of this panel require~ the hollow core area to be filled with a cementitious or other solid material after it has been placed at the job site. This fill provides the panel's permanent stability and the necessary structural support. In other panel design variations, thicker skins are required and another material layer is added during manufacturing to act as forming for the hollow core area. However, because of the additional requirements, neither of theee panel designs provide f'or any real material savings over conventional methods.

203~1rj~

In all cases, the thickness ot the panel skin iq dependent upon the type of structural f'orces to which it is subject. These panels are typically designed for load bearing purposes which require a thicker prefabricated skin than necessary to withstand only latèral forces. Therefore, the thicker skins required by the these existing hollow core panels require more concrète and reinforcement material which in turn increases the panel'~ cost and weight and makes handling more difficult.
The existing hollow oore panels offer little fle~ibility in terms of customizing their structural int~grity and material requirements for different applications. In certain situations, the handling method requires the panel to have greater structural strengths than are necessary for the application intended. Thus, in many instances, these panels contain much more material and structural strength than is needed for the particular application.
This causes the panels to be uneconomical replacements for conventional materials and methods.
Finally, most of the existing concrete buildin~ panels require a continuous foundation which of'f'ers no advantage over conventional construction. Furthermore, many of' these panels are difficult to integrate into a typical building project and require additional steps such as welding to connect them with other materials. These additional steps makes them less desirable or uneconomical for many building applicationq and projects.

, :
' ~' ' ' ,' ' ' ' : , , 2 ~ 3 8 ~ ~ ~

SUMMARY OF TH~ INVENTION
The present invention provides a highly flexible, concrete building panel design and low cost manufacturing process that enables the connection of two separately finished skins with a solid cementitious bond while creating a hollow core area between said skins. The lightweight panel contains internal formwork ~or the structural columns and beam which are cast in situ after said panel has been placed. In addition, said hollow core area may be left hollow, partially filled or totally filled with various types of insulating materials as may be desired for a particular application.
Due to the high quality finish of both skins, the panel offers significant cost savings in each of its numerous applications. Furthermore, because of the fle~ibility of the hollow core area, the panel may be customized for different structural or insulating applications. The panel may be used for structural or non-structural purposes, for wall, floor and roof panels and for non-building purpoqes such aq noise barriers, fence walls and retaining walls.

OBJECTS AND ADVANTAGES
Accordingly, it is the primary objective of this invention to provide a lightweight, concrete building panel with internal formwork, for the column and beams, which are cast in situ after the panel ha~ been placed. Thus the majority of the structural elements, materials and weight will be created during the installation proce~s, after the panel ha~ been manufactured and .
, . -:. ,', ~ . ` `
`:

2~3~

handled. This internal formwork also provides a more efficientdesign and utilization of the materials needed for structural purposes and can easily be altered and cu~tomized to Illeet the different structural requirements for various applications.
Another object of the invention is khe utilization of internal, cementitious spacers that provide a solid connection between the two skins.
Another object of the invention is to retain substantial fle~ibility for use of the hollow core area in that it may be left void, partially filled or totally filled with a variety of materials or combinations to meet whatever requirements or functions that may be desired for a particular application.
Another object of the invention is to produce a panel with two high quality finished faces that are horizontally cast and may be created by a form liner, the use of aggregates or by attaching various cladding materials during the manufacturing process.
A further object of the invention is to provide a method by which various cladding materials may be attached to the panel's finished face during the manufacturing process.
A further object of the invention is to provide a panel that is adaptable to use with either a continuous foundation or with only a column footer cast prior to or after the panel has been set in place.
A further object of thi~ invention is to provide a building component that easily integrate~ with convenkional methods and materials.

:. . ` ' .

~ : : ,.
; ~ ' .
: ~ ' ' ' ' :

~ ~ 3 ~

A further object of the invention i8 -to utilize ~imple, inexpensive molding equipment and processes for the panel's fabrication, that is easily adaptable for different size and shape configurations and can be used on the building site . Such a process includes an open working environment to provide ease of access to manutacture each skin and for embedding or attaching utilities, insulationt window and door frames or other items into the panel or provide for any other internal functions.
A further object of this invention is to provide a highly flexible, prefabricated hollow core panel that is easily altered and custom designed to effectively and efficiently satisfy many diferent applications.
A further object of the invention is to provide for fast and easy handling of the lightweight panels by usin~ small equipment and providing internal connections.
Further objects and advantages of my invention will become apparent rom a consideration of the drawings and ensuing description of it.

B~IEF D~SC~IPTION OF THE D~AWINGS
FIGURE 1 is a perspective view of a typical wall panel detailing the interior core area formwork, the solid spacers and the inished, exterior skin~.
FIGURE 2 is a typical wall panel that show~ an alternative spacer design for the interior core area.

. - ~ .

`
, .. . . .
';:

2~3~

FIGURE 3 is another design alternative that shows both the internal spacers and the panel's columns and beam precast as part of the manufacturing process.
FIGURE 4 is a perspective view of the panel's f'orming equipment and the two molds used in it's manufacturing process.
FIGURE 5 is a cross section of a typical panel skin, as it is being cast in a mold.
FIGURE 6 is a perspective view of Figure ~ after the spacers and the internal formwork has been placed on the interior side of the first skin.
FIGURE 7 is a cross section of the first skin mold as it is being rotated for connection to the second skin.
FIGURE 8 is a cross section of the two skins being connected with the completion of a 180 degree rotation of the first skin and mold, and embedment of the spacers and internal formwork into the wet, cementitious second skin.
FIGURE 9 is a detailed cross section of a completed panel as it would appear in Fi~ure 8 when the mold are removed.
FIGURE lO shows the completed panel being removed from the molding equipment.
FIGURE 11 is a perspectiYe showing a wall panel placement on a foundation that contains reinforcement bars.
FIGURE 12 shows the placement of several wall panels ready for the internal columns and beam to be cast in situ.

',, :

2~38~Y~ ~

DESCRIPTION OF THE PR~F~RED EMB~DIME~T
The invention consists of a concre-te, hollow core building panel as generally shown in Figure 1. The panel l0 is composed of two thin concrete skins 12A and 12B that are connected by ~enerally solid, concrete spacers 14 which are partially embedded or otherwise bonded to the skins 12A and 12B. The spacers 14 may be of different shapes, configurations and materials including concrete, plastic and others and may also contain reinforcement material such as wire mesh to enhance both their individual strength and the bond with the skins 12A and 12B.
The panel design also includes internal formwork 15, used for concrete columns and beams that are cast in situ after the panels have been placed. The formwork, 15, forms the perimeter of the hollo~ core area, 18, and prevents concrete and other materials from entering the hollow core area, while also providing the formwork for the columns and beam that are internal to the panel 10, and cast in situ. The internal formwork 16, may be composed of several different types of materials and placed in different locations to achieve more or larger columns and beam. This formwork 15 is also partially embedded or otherwise connected to the skins 12A and 12B and remains permanently in place after the columns and beam have been cast.
In order to facilitate the easy handling of the panels, hooks 13, may be embedded into the spacers 14, or otherwise attached to the panel 10.

.
: ` :

.

..

~038~

Figure 2 shows alternative design confi~urations of the cube type spacers 1~ and the elongated type spacers 16.
Figure 3 shows a variation of the panel desi~n where the columns 20 and beam 21 have been placed within the panel during the manufacturing process as opposed to being cast in situ at the building site. Of special note are the reinforcement bars 22, protruding from the columns and may also be included with the beam. These reinforcement bars 22 are designed to be set in formwork at the building site and cast in situ thereby creatin~
the structural bond between the panel and the foundation or other adjoining structure.
Figure 4 shows the forming equipment used to manufacture the panel. Included are the two molds 25A and 25B, and a central hinge device 2~, over which the two skin molds rotate. A special feature of this manufacturing process is the ability to cast each skin in an open work environment to facilitate placement of the internal spacers7 formwork, utilities and other features.
The manufacturing equipment may consist of a single unit or three or more separate parts brought together for rotating or removing a panel. The equipment may be fixed, transportable or even mobile.
The manufacturing process begins by casting a first skin, 12A, in a horizontal mold 25A in figure 6. Prior to casting the cementitious material, either a form liner or Qome type of cladding material 27 may be set in the bottom of the mold 25A.
The cladding material 27 may consist of various types of tile~, stones, canvases, cloths, paper, metals, etc. which are placed : ~ .

face down in the mold. In some cages, an adhesive material may be placed on the back of the cladding material to ensure an adequate bond. A cementitiou~ layer 29 i~ then cast on top of the cladding material to create the panel's first qkin. Reinforcement material 30 consisting of a mesh, fibers or other product may be included in the cementitious skin.
While the cementitiouq skin 12A is still wet, either precast or cast in situ spacers 14 are placed on top, in the desired position and partially embedded or otherwise bonded to the cementitiou~ layer as shown in figure 6. Also, the desired internal formwork 15 or the actual columns ~nd beams (figure 3) are po-~itioned and partially embedded or otherwise bonded to the cementitious skin. The columns and beam may be precast or cast in situ over the skin.
After the first side skin 12A has sufficiently cured, a second, separate skin 12B is prepared in the same manner as shown in figure 5. As demon~trated in figures 7 and 8, while the second cementitious skin 12B, is still wet, the first skin 12A is rotated 180 degrees with the spacers 14 and internal formwork 15 firmly embedded. This rotation is performed by rotating the mold 25A
with the cementitious skin 12A still intact and clamped 28 to the mold 25A. The rotation is facilitated by a large hinge device, 26, to which each mold 25A and 25B are connected during the rotation process.
Once the rotation is completed a~ ~hown in figure 8, the spacers 14 and the internal formwork 15, are both partially embedded or otherwise bonded to the cementitious second skin 12B.

., - , - , ,.

~3~ 2 The bond may be enhanced by by a connecting wire or similar material 17, that is encased in the spacer~ and embedded into each of the skins 12A and 12B as detailed in figure 9.
When the second skin 12B has ~ufficiently cured, the finished panel is removed from the mold and ready ~'or placement on the building site. As shown in figure lO, this is accomplished by rotating the second mold, 25B, 9O degrees, -to a vertical position, with the finished panel lO still in tact. The panel lO, is then lifted vertically from the mold 25B and placed in a qtorage cart or in its final placement position.
Panel installation is accomplished by placing the panel lO on a previously poured foundation 31, as ~hown in figure 11. The appropriate reinforcement 32, has been embedded in and e~tending from the foundation 31 in the vicinity OI' the column voids 33 that have been created by the internal formwork l5 contained in the panel lO.
Once the panels have been set in place, they are shored and additional steel reinforcement is placed in the column and beam areas, 33 and 34. The column area 33, and beam area 3~ are then filled with concrete as shown in figure 12. This concrete creates the bond between the panels lO and the foundation 31 as well a~
provides the structural integrity to withstand the various loads for which the panel was designed. The internal formwork 1~
i contains the ca~t in situ concrete to only the column and beam areas and leave~ in tact the hollow core area 18 that may remain void or have been previously fill0d with an insulating material.

~3~ J

The exterior face of each of the panel skins, 12A and 12~, may be finighed with a variety of materials and methods either prior to or after fin~l placement. Depending upon the materials and cladding method, seamq may be covered, patched, hidden, revealed or otherwise treated. In the case of canvas, cloth or paper like cladding, the seams may be patched with the con~entional process of tape and a joint compound.
An important aspect of the in~ention i3 the fle~ible molding equipment from which different panel sizes and shapes can easily be produced. The molds 26A and 25B can be of most any size and a variety of shapes including convex, concave, curvilinear, flat, and even a combination of these. The mold sides may be moved or positioned at various angles or curveq. E~en the panel 10 thickness can be altered by changing the spacers 14 size and slightly modifying the mold positions.
The open work environment above each mold 25A and 25B, and ~ . .
the fact the top of the cementitious skin 12A and 12B in these molds are the interior section of the panels, greatly facilitate the placement and embedding of window and door openings, frames and units, utilities and other features that are not yet apparent.
The panel design and its manufacturing and placement process provide great flexibility for using a variety of insulating materials and methods. Either rigid or non-rigid insulation can be installed during the manufacturing process by attaching it to the inside face of skin 12A after it haq cured and prior to rotating skin 12A to bond with the second skin, 12B. Other insulating materials can be blown or poured into the panel's , "

203~

hollow core area after the panel 10 has been placed and prior to castin~ the beam 21 or other panel cap.
There are a number of different foundations that can be utilized with the panel. These include a continuous footer, a slab floor or foundation, a column footer, or another column and beam. These foundations may be cast prior to or after the panel has been set in place and may con~ist of di-fferent materiaLs such as steel or wood. The panels may be stacked to obtain greater heights or for multistory purposes, SUMMA~Y, RAMIFICATIONS AND SCOPE
Thus the reader will see that the hollow core, concrete building panel of the invention provides for a highly fle~ible design, that enables it to be efficiently used in a variety of applications, and a low cost manufacturing process that produces a very cost effective product. Furthermore, the hollow core concrete building panel has the additional advantages in that:
it contains internal formwork that enables the columns and beam to be cast in situ, which in turn provides for a more efficient use of materials and a lighter panel for handling purposes;
it utilizes internal, concrete spacers, that are solidly connected to the skins, and act to create the hollow core area by holding the skins both together and apart while occuping only a fraction of the hollow area between them, , ~ .
.

,: , 2, ~ '~ 8 ~

it is ~anufactured in ~uch a way that both sl~ins are cast in a hori~ontal position -to enable att~active finishes by using either form liners or a cladding ! material attached during the manufacturing process;
* it offers the flexibility to be used with several different types of foundations and may even be stacked to achieve greater hieghts;
it's hollow core area offers much flexiblity in terms of placin~ different types of insulating materials, utilities and other special features;
it's manufacturing process requires very simple and inexpensive equipment that can be u~ed in a central plant or on the job site.
While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible. For example the two individual skins may be attached in a different manner either during the manufacturing process or at the job site.
Or, the panel's columns and beam may be internally cast durino the manufacturing process and otherwise attached to the foundation, etc.
Accordingly, the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the example~ given.

:

, - ' . ' .

Claims (19)

1. THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
   PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
   .A method of manufacturing hollow core, concrete building panels comprising the steps of:
   a. casting a first concrete skin in a mold and b. means of attaching solid spacers to the internal side of said first skin and c. casting a second skin and d. means of attaching the internal solid spacers on the first skin to the internal side of said second skin e. whereby the resulting building panel contains two skins, separated by solid spacers that create an internal, hollow core area between said skins.
2. 2. The building panel of Claim 1 wherein the skins are cast face down in a horizontal mold with a predetermined texture which will be the resulting exterior surface texture of said skins.
3. 3. The building panel of Claim 1 wherein objects such as door and window frames, utilities and other objects can be cast internally, between the two skins, during the manufacturing process.
4. 4. The building panel of Claim 1 wherein the size, shape and configuration may be altered.
5. 5. The building panel of Claim 1 wherein insulating materials may be placed into said hollow core area.
6. 6. The building panel of Claim 1 wherein said skins contain reinforcement materials.
7. 7. The building panel of Claim 1 wherein the hollow core area is used to contain a beam, columns and other structural and connecting members.
8. 8. The building panel of Claim 7 wherein the beam, columns and other structural and connecting members are placed in said hollow core area during the manufacturing process of said building panels.
9. 9. A method of placing said building panel of Claim 7 wherein the foundation may consist of column footers versus a continuous footer.
10. 10. A method of placing said building panel of Claim 7 wherein the foundation may be cast in situ after the panel has been set in place.
11. 11. The building panel of Claim 1 wherein permanent formwork is placed in the hollow core area to create areas for casting a beam and columns and other structural and connecting members.
12. 12. A method of placing said building panel of Claim 11 wherein the columns, beam and other structural members are cast in situ at the building site, after the building panels have been set in place
13. 13. The building panel of Claim 1 wherein said first and second skins are wet at the time the solid spacers, internal formwork, beam, columns and other structural and connecting members and any other objects are set in place on the internal side of said skins and become embedded into said first and second skins.
14. 14. The building panel of Claim 13 wherein said solid spacers have connecting devices extending therefrom and are embedded into said wet skins.
15. 15. The building panel of Claim 1 wherein said solid spacers, beam, columns and other structural and connecting members and any other objects are cast in situ onto the internal side of said first skin.
16. 16. A method of placing a cladding material on a building panel comprising the steps of:
    a. placing a cladding material face down in the bottom of a horizontal mold and b. casting a concrete material on top of said cladding material to create a panel skin c. whereby the resulting skin surface finish will consist of the facing side of the cladding material.
17. 17. The cladding material method of Claim 16 wherein an adhesive material is placed on the back side of said cladding material prior to casting the concrete material to create a panel skin.
18. 18. The cladding material method of Claim 17 wherein said cladding material consists of cloth, canvas, paper or other similar interior wall building material.
19. 19. The cladding material method of Claim 16 wherein an adhesive substance is added to the concrete material cast onto the back of said cladding material.