Structural panel and method of fabrication

Abstract

A process for manufacturing a structural panel includes determining structural loads to be placed upon the structural panel. The structural panel is manufactured from at least two generally parallel and spaced-apart thin-shell cementitious skins that are joined by a truss. The thickness of each cementitious skin is selected to meet the structural loads to be placed thereon and each skin is shaped to center reinforcement in the skin.

Description

RELATED APPLICATION [0001] This application claims priority from provisional patent application Ser. No. 60 / 621,195, filed Oct. 22, 2004, and claims priority as a continuation-in-part of U.S. patent application Ser. No. 10 / 823,082, filed Apr. 12, 2004, which claimed priority as a continuation-in-part of U.S. Pat. No. 6,718,712, issued Apr. 13, 2004, which claimed priority from provisional application Ser. No. 60 / 127,224, filed Mar. 31, 1999.BACKGROUND OF THE INVENTION [0002] The present invention relates generally to construction materials. More particularly, the invention concerns structural panels and methods for their manufacture which employ fillers, together with a reinforcing structure comprised of commercially available components, which when assembled and faced with a durable covering provides a building component. [0003] Prefabricated structural building panels are utilized in the construction of structures such as houses and commercial, industrial and institutional buildin...

AI Technical Summary

Benefits of technology

[0025] The present invention relates to pre-fabricated structural panels which utilize commercially available materials, and a cost-efficient and simple method of construction. Accordingly, the main objective of this invention is a novel and improved structural panel which can be constructed in a wide variety of thicknesses, widths and lengths without dependence on limited source and costly materials.

Problems solved by technology

While these structural panels have been useful in the construction industry, they have had the disadvantage of being costly and sometimes unavailable in rural areas.

They also have the disadvantage of not being able to be custom engineered and fabricated to meet the load demands of a particular structure and are only available in a few, structurally limited, configurations.

However, such materials are manufactured from petrochemical substances and have potential environmental damage issues associated with them.

There is also the increasing price of these fillers due to the finite quantity of petroleum resources and their depletion.

Additionally, there is the difficulty in obtaining plastic foams in developing countries and remote locations as well as the high cost of shipping to these locations due to plastic foam volume to weight ratio.

At least one company produces lattice structures having forty-five degree (45°) bends for use in their structural panels, a configuration that is more structurally sound but which also increases the cost of the structural panel due to production economics.

Typically, such structural panels are limited to only one thickness option.

While structurally superior, these designs result in increased expense passed to the end consumer.

The design of the structural panel may also be complicated which further increases production costs.

In rural areas and foreign countries many of these specialized materials are not available and must be shipped, further increasing expense or prohibiting the area from using pre-fabricated structural panels altogether.

Previous methods of fabricating panels with a wire truss structure and a wire face mesh have been made utilizing machines and techniques which resulted in panels being limited in the dimensions of the components employed.

If a different panel was desired, a new machine was needed to make the new panel type or, at least, extensive, time consuming, and costly modifications or re-fabrication of the machine, was required.

The manufacture of all Structural Concrete Insulating Panels (SCIP) to date has involved significant capital investment due to the complexity of the machinery required, or, in the case of low-cost methods, it has been very limited in breadth of capacity in terms of sizes of panels able to be produced.

In addition, most methods of production have required high levels of technical skill to operate as well as utility (electrical and water) and other support not readily available in developing nations.

Also, all other systems have a linear manufacturing path which results in the entire operation being shut down if any part of it fails.

A significant drawback to this design is the linear product flow.

While longer apparatus' could be fabricated, allowing for longer panels, this compounds the problem of other work halting while the panel is in the compression section of the apparatus.

This results from there being much more surface to affix the face mesh to, thereby lengthening the time that other, shorter duration tasks would be idle.

While these idleness problems might be overcome through task realignment of the crew, a more significant problem is that all previous machines were limited in their capacity to accept a wide variety of panel thicknesses.

These early apparatus' also had as inability to change the position of the core relative to the face of the panel.

These problems result from the nature of the apparatus'.

These two problems are significant because the ability to employ deeper trusses allows for greater panel strength and greater spans.

This routinely results in the need for the upper concrete skin to be thicker than the lower skin.

Both the linear work flow and the limited thickness flexibility result in the means of increasing product output being the addition of entire machines.

The nature of the apparatus' in the gauge and depth of the wires in the trusses and the gauge and density of the wires in the face mesh also limited previous panel manufacturers.

This is a significant problem and demonstrates a need that, if the load on the structure increases, increasing the gauge or depth of the truss and / or increasing the gauge and density of the mesh allows for a panel to be produced that can resist this increased load.

No previous SCIP manufacturer has undertaken an engineering approach to the design of an SCIP.

This is principally because their output was limited in variation.

A last issue is that because such machines have been in the public domain for so long there is no opportunity for patent protection and the resultant business benefits that flow from such protection.

Portland cement is a commodity that is relatively expensive.

It is costly to produce, transport, store and has steadily risen in price over time.

Unreinforced concrete has excellent compressive strength but comparatively poor tensile strength.

However, reinforcing steel is a commodity that is relatively expensive.

Reinforcing steel is costly to produce and it has steadily risen in price over time.

Reinforcing steel is also very heavy and as a result costly and dangerous to install.

Reinforced concrete has, as it's single largest drawback, it's own mass.

It is very heavy, typically weighing over 150 pounds per cubic foot.

In fact, it is so heavy that a significant percentage of the total reinforcing steel required in concrete structures is there to overcome the loads imposed by the mass of the concrete itself, commonly known as the dead load.

Lastly there is a very high cost in forming concrete.

The result is that the formwork is very costly.

Hence, this temporary structure is the most costly element of a concrete structure.

All of the above combine to result in a construction process that is slow and costly.

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