Patent Application
20120233950
This invention relates generally to concrete wall systems, methods for making concrete wall systems, and spacers used in concrete wall systems.
Many structures and buildings are made with concrete walls. Traditionally, this type of construction involves setting up forms, pouring concrete between the forms, and then removing the forms after the concrete hardens. It is also common to utilize reinforcing bars (commonly referred to as “rebar”) in the concrete.
Australian Patent Application No. 2000101212 discloses another type of concrete wall that comprises an opposing pair of formwork boards and a plurality of wall spacers located between the formwork boards. Reinforcing bars are placed through respective openings formed in the spacers, and the cavity between the formwork boards is then filled with concrete. The formwork boards remain in place, acting as the finished internal or external wall surface.
The concept disclosed by Australian Patent Application No. 2000101212 has several drawbacks. For instance, the spacers are box-shaped and thus occupy a considerable volume when packed for shipping, thereby resulting in relatively high shipping cost. Australian Patent Application No. 2000101212 also does not disclose techniques for efficiently assembling the formwork boards and spacers. Nor does Australian Patent Application No. 2000101212 teach how to build high structures or columns or efficiently incorporate electrical conduits and the like within the pre-filled wall prior to pouring concrete.
The above-mentioned need is met by the present invention, which provides a concrete wall system comprising first and second opposing wall panels and a plurality of spacers disposed between the first and second wall panels. A plurality of reinforcing bars is placed between the first and second wall panels and supported by the spacers, and a concrete core is disposed between the first and second wall panels such that the spacers and the reinforcing bars are embedded in the concrete core. Each one of the spacers has a cup-like body defining a closed first end and an open second end with a flange formed on the second end. The spacer bodies are tapered so that the spacers are stackable.
The present invention includes integrated concrete wall systems that comprise two opposing wall panels separated by a plurality of spacers and a concrete core located between the two wall panels. The spacers position the two wall panels relative to one another. Specifically, the spacers maintain the two wall panels parallel to one another and spaced apart a particular distance to insure that the resulting wall system has a uniform and desired thickness. The spacers are also adapted to support reinforcing bars, as well as other items such as electrical conduit, in place between the wall panels before the concrete is poured into the inter-panel space.
Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views,
The exterior or outwardly-facing surface of the base piece 20 can be attached to the one of the wall panels, and the outwardly-facing surface of the flange 22 can be attached to the other wall panel. These surfaces can be attached via any suitable means, such as adhesive or the like. Because the flange 22 and the base piece 20 are substantially parallel, an attached spacer 10 functions to maintain the opposing wall panels in parallel relation and at the desired spacing (which is determined by the length of the spacer 10).
The body 12 includes an opening 24 formed in each one of the four side walls 18 for receiving reinforcing bars (vertical and horizontal) as well as other items such as electrical conduit. As described in more detail below, a number of spacers 10 are deployed to hold the reinforcing bars in the proper positions during construction of a concrete wall system.
The body 12 is tapered with the four side walls 18 converging slightly so that the cross-sectional area of the closed end 14 is smaller than the cross-sectional area of the open end 16. The tapered configuration and hollow cavity of the body 12 make the spacer 10 stackable; that is, multiple spacers 10 can be stacked together. This stackable spacer configuration greatly reduces packing and shipping costs as large volumes of the spacers can be packed and shipped in a minimum of space.
The spacers 10 can be made as a one-piece construction, such as with an injection molding process. Injection molding is highly automated, and the spacers 10 can be molded and stacked as they are produced, which further lowers packing costs. The spacers 10 can be made of any suitable material, including plastic. Plastic materials are generally lightweight and will not corrode when set in concrete.
Referring to
A plurality of spacers 10 is disposed in the inter-panel space 36 between the first and second wall panels 32, 34. The base piece 20 of each spacer 10 is attached to the first wall panel 32, and the flange 22 of each spacer 10 is attached to the second wall panel 34 in any suitable manner. For example, the base pieces 20 and the flanges 22 can be attached to the respective wall panels using a fast-drying urethane glue. In the illustrated embodiment, the spacers 10 are arranged in a grid-like layout of vertical columns and horizontal rows. The number and spacing of the spacers 10 will depend on the structural design. For example, about forty spacers 10 would typically be equidistantly spaced on a four-foot by ten-foot panel as would be used for most home or commercial construction. This assemblage of the first and second wall panels 32, 34 and the spacers 10, referred to hereinafter as the shell assembly, is typically made at a factory and then transported to the construction site. At the construction site, the shell assembly is slip fit over its floor channel 38 and the wall panels 32, 34 are fastened thereto as described above. Reinforcing bars are then interlaced with the spacers 10. Specifically, a vertically-extending reinforcing bar 42 is placed to extend through the openings 24 formed in the horizontally-oriented side walls 18 of each column of spacers 10, and a horizontally-extending reinforcing bar 44 is placed to extend through the openings 24 formed in the vertically-oriented side walls 18 of each row of spacers 10.
Once the wall panels 32, 34, channel 38, spacers 10 and reinforcing bars 42, 44 are assembled as shown in
Referring to
The outer wall panels 34 could comprise a board of an insulating material (such as polyurethane (PU) closed-cell foam or expanded polystyrene (EPS)) having an outer finish surface of wood, metal or plastic clad thereto. Pre-finished outer wall panels 34 with an insulating foam board would provide thermal insulation for the building, thereby eliminating the need for a separate layer of insulation and consequently saving labor costs and speeding up overall construction time. Any number of exterior sidings, including horizontal or vertical metal clad sidings, can be applied to the outer surface of the insulating foam board using pressure sensitive adhesives. For example, foam panels can be purchased pre-finished with vacuum bag applied exterior sidings such as aluminum and steel. To quickly apply finish-lapping strips to joints (not shown), tape adhesives can be used and can withstand temperatures to 200 F. Concrete adheres well to PU foam, which has an R-value of 6.5 per inch compared to an R-value of 4 per inch for EPS foam.
As an alternative to insulated outer wall panels, the concrete wall systems 30A, 30B could be provided with a third wall panel (not shown) arranged in parallel, spaced-apart relation outside of the outer wall panels 34 (which would thus become intermediate wall panels). The spaces between these sets of panels would be filled with insulating material.
Each concrete wall system 30A, 30B further includes a plurality of spacers disposed in the inter-panel space 36 between the wall panels 32, 34. One of the wall systems 30A uses the tapered, cup-like spacers 10 shown in
The construction further includes a corner assembly 56, described in more detail below, which connects the two perpendicular concrete wall systems 30A, 30B and completes the building corner. Prior to installing the corner assembly 56, the vertical and horizontal reinforcing bars 42, 44 are interlaced with the spacers 10/48. In addition, electrical conduit 58 can be installed by insertion through the openings 24/54 of selected spacers 10/48. In the illustrated embodiment, additional spacers 10/48 are located between columns and rows of spacers 10/48 that hold vertical and horizontal reinforcing bars 42, 44 in order to support electrical conduit 58 at a desired height or heights. Preferably, each such additional spacer is centered between a two adjacent columns of reinforcing bar-holding spacers and between two adjacent rows of reinforcing bar-holding spacers.
Openings for doors and windows can be zip cut in the shell assemblies at the factory where they are made or on site, with pre-assembled rough opening spacers (not shown) inserted and fastened in place to the wall panels prior to pouring concrete. The corner assembly 56 comprises two corner pieces 60 joined together at a 90 degree angle and two pre-glued strips 62 that are used to attach the corner pieces 60 to the corresponding outer wall panels 34 once the reinforcing bars 42, 44 and conduit 58 are all installed. Generally, the corner pieces 60 and the pre-glued strips 62 would be used with fiber cement panels, which are chamfered on the outer edges to apply finishing tape for application of other finish coatings. If the outer wall panels 34 have insulating foam thickness pre-applied inside, a slot would be cut in the foam adjacent to the inside surface of each wall panel to accommodate the pre-glued strips 62. Any number of combinations of wall panels 32, 34 can be used providing they are engineer approved for the particular construction system.
Reinforcing bars, conduit, junction boxes and all interior plumbing are installed prior to the pour of concrete into inter-panel space 36. Once the wall panel assemblies are all in place with reinforcing bars secured and connected and all conduit is secured and connectors glued, junction boxes 64 can be installed. Because junction boxes are located at an engineered height from the floor, the conduit 58 is placed at this height. Junction box panel openings can thus be rotary zip cut into the inner wall panel 32 anywhere along the conduit length, and the conduit 58 is cut to produce a gap equal to the exact outside width of the junction box 64 and aligned with the junction box panel opening. Glue is applied to the fittings 66 formed in the sides of the junction box 64, and the junction box 64 is then inserted into the opening in the inner wall panel 32 and the gap in the conduit 58 such that tabs 68 on the junction box abut the inner wall panel 32. Thus, as many junction boxes as needed can be quickly and efficiently located anywhere along the length of the conduit with a tight and secure fit made to the junction box 64, the conduit 58 and the inner wall panel 32 before pouring concrete. Conduit that does not have a well-defined location can have junction boxes and fittings pre-installed as wall panels are set, which, with location rough-marked on the inner wall panel 32 and/or with a iron washer (not shown) taped to the inside a plastic junction box, can also be quickly and exactly located later with a magnet to rotary zip cut the junction box opening into the inner wall panel 32. Channels (not shown in
Turning to
Vertical reinforcing bars 42 are inserted through openings 54 in the PVC pipe 50 and tied to the horizontal reinforcing bars 44. The openings 54 are larger than the reinforcing bars 42 in order to receive the reinforcing bars 42 and still have clearance to allow the PVC pipe 50 to fill with concrete. The amount and size of the vertical and horizontal reinforcing bars 42, 44 depends on the size of the column 70 with as many horizontal layers of reinforcing bars 44 as needed to meet code. Each layer of spacers 48 and horizontal reinforcing bars 44 would be shifted 90 degrees with respect to its adjacent layers. In other words, the layer of spacers 48 and horizontal reinforcing bars 44 located directly below the layer shown in
Once the panels 72-75, spacers 48 and reinforcing bars 42, 44 are assembled, concrete is poured into the assembly. The concrete fills the interior of the assembly and also flows into the spacers 48 via the openings 54. The concrete cures and forms a concrete core that provides structural integrity to the column 70.
For supporting concrete wall systems in multi-story structures, wall system thickness at the ground floor will start at a relative thick value, say twelve inches thick. The wall system thickness will be gradually reduced for higher and higher floors, such as to ten inches, then to eight inches, then to six inches, then to four inches thick per the structural engineer's design for a twenty-four story building, for example, to create an earthquake and fire proof building of high quality. To accomplish this, stackable spacers could be mass produced at the various widths and panel assemblies fit over and secured to the standard width channels that are attached to the concrete floors at each story to accommodate securing and lining up panels for pouring concrete. Alternatively, PVC fabricated spacers could also be produced as necessary for thicker starting walls. And regardless of climate, as noted previously, either PU or EPS insulated foam board outer panel can be used, or a second outside insulating space can be created with a third panel and filled with approved insulating materials to construct a strong, airtight structure enabling good air quality control and being well insulated. Everything combines to make highly energy efficient, quality buildings.
While specific embodiments of the present invention have been described, it should be noted that various modifications thereto can be made without departing from the spirit and scope of the invention as defined in the appended claims.
