Static structures (e.g. – buildings) – Facers; e.g. – modules – mutually bonded by internal settable... – Laterally related modules; e.g. – back-to-back
Utility Patent
1998-11-02
2001-01-02
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Facers; e.g., modules, mutually bonded by internal settable...
Laterally related modules; e.g., back-to-back
C052S429000, C052S439000, C052S563000, C052S570000, C052S588100
Utility Patent
active
06167669
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to the construction of reinforced concrete and steel structures, specifically to such structures erected using CMU's (Concrete Masonry Units).
Further this invention relates to interlocking factory extruded, Permanent Forms for Concrete, that are made from Polyvinyl—Chloride (PVC), that are assembled on site
(2) Description of the Related Art
Cement is a mixture of a powder of alumina, silica, lime, iron oxide and magnesia burned together in a kiln and finely pulverized and used as an ingredient of mortar and concrete. Mortar and concrete is widely used in construction. Mortar is a mixture of cement, lime, sand and water. Mortar is used as a plaster, or to bond clay bricks and concrete blocks together to erect a structure. Concrete is a mixture of cement, sand, gravel, and water. The more cement, added to the mix, makes the concrete stronger.
Wet concrete is sometime poured into forms, and steel is added to give it more strength, to hold the concrete in place, until it has cured. This is referred to as, a steel reinforced concrete structure
Usually these forms are made of wood, metal or combinations of each, but forms can be made from almost anything. Erecting these forms, and striping them after the concrete has set is a slow expensive process that needs to be improved on.
The problem is designing a form, that is easy to manufacture in a factory. A form, that is light weight, has very few parts, and is easy to transport to different job sites. A form, that is easy to assemble, or to modify on site. A form, that can be left in place, to become part of the structure and protects the cured concrete, after it has set, from damages caused by the elements. A form, that can be easily inspected, at any stage of erection, to make absolutely sure that all the reinforcing steel and the utilities are in place, prior to filling the form with concrete. A form, that can be inspected during the pouring of the concrete, where you can actually “see” the concrete filling the form. A form that is “clear” so that after the pour is finished, you can actually “see”, the concrete inside and you can be absolutely sure there are no air pockets or voids.
There have been many attempts at designing a form, that solves some of the problems relate to construction of steel reinforced concrete structures.
The most successful, stay in place form, on the market to accomplish this is the Concrete Masonry Unit commonly referred to as a “Concrete Block”. Its sizes and shapes and methods of installation are shown, in detail, in the Architectural Graphic Standards for Architects, Engineers, Decorators, Builders, Draftsmen and Students of the Construction Industry by Charles George Ramsey A.I.A and Harold Reeve Sleeper F.A.I.A.
Most Architects and Engineers prefer CMU construction, it is also preferred by the local building codes. The units themselves are inexpensive. The average concrete block plant can produce 24,000 units per day, but there are several disadvantages in using the CMU.
One is its weight. The average CMU weighs 35 lbs. The average block plant requires more than 420 tons of raw material, sand, rock, cement and water, to operate for one 24-hour period. That is about 19 truck loads, delivered to the plant, per day. The average new house, using CMU construction, contains 1,800 units, with a total weigh of 31.5 tons.
The CMU's are expensive to transport. The blocks are large and bulky, because of the hollow cell design. The block is delivered on large diesel powered trucks, that are equipped with cranes to pick up the “cubes” of a block. Each cube of block, has 72 block ea. and weighs 1.25 tons.
Each truck carries 18 cubes of block, or 1,296 units. It takes two, truck trips of block, per house. It takes one truck, to deliver the precast lintels and window sills It also requires another truck to deliver the sand, mortar mix, and re-bar, and still another truck to haul away the waste. This process is not only expensive, but it has a grave impact, on the quality of the air, that we breathe.
Some of the Prior Arts address this problem. The high cost of shipping, by offering a light weight form, but they fail to point out the impact of so many truck trips has on the environment.
The labor cost for laying CMU's is expensive. The blocks have to be laid one at a time in a brick like fashion, so that the hollow cells line up vertical to form wells, so that the steel can be installed and the concrete can be poured into the wells. The blocks have to be carefully laid to a string line and each has to be plumb and level. Each unit has to be set in a bed of mortar. Mortar has a tendency to shrink slightly and may pull away from the masonry units causing fine, almost invisible cracks at the junction of mortar and masonry units. These cracks allow moisture to enter the wall cavities.
This is one, of the hardest skills to master, in the construction industry. It takes experienced professionals and they are paid accordingly.
Some of the Prior Arts address this problem by offering a form that is easy to assemble on site by unskilled laborers.
Local conditions frequently demand special construction methods that require additional strength by reinforcing the walls with reinforcing rods encased in the poured concrete. The walls may require horizontal reinforcing rods, this requires a special block called a “lintel block” with knockouts on the ends and in the center. Local building codes may require forming a bond beam, at each story height. This usually requires another sub-contractor skilled in structural concrete forming.
The forming material, usually precut ¾″ plywood, “H-clamps,” or “snap-ties and pig's feet” have to be delivered to the job site and erected. After the bond beams are poured with concrete, the wood forms have to be stripped, cleaned and shipped or stored until the next job.
Some of the Prior Arts address this problem by offering a “form” that stays in place to reduce the cost of wrecking, and cleaning reusable forms.
Where vertical reinforcement is required in CMU construction, it is usually located at building comers, jambs of wall openings and at regular intervals between wall openings. In placing the vertical reinforcement, advantage is taken of the vertical alignment of the hollow block cores which form wells, into which the reinforcing bars are placed and filled solid with concrete. If the wells are not rodded clean, of the extruded mortar and the debris removed prior to pouring, the concrete fails to fill the well solid with concrete. This mistake is usually not discovered, until after a disaster happens, such as earthquakes and hurricanes, because the units are made of a solid material, and you cannot “see” inside of the blocks to “see” if the cells were filled with concrete and steel.
None of the Prior Arts, has addressed this problem, until now. This Applicant offers a “Clear Form” extruded, from a clear resin of polyvinyl chloride for Reinforced Concrete Structures. to aid the Inspectors, so that they can make thorough complete inspections.
The end results of a structure built using Concrete Masonry Units, is a steel reinforced column and beam structure with hollow CMU's between the columns, that is exposed to the elements. When water penetrates the concrete the steel will rust. When the steel starts to rusts it swells and then the concrete will crack.
Some of the Prior Arts address this problem, by offering a thermoplastic form, with the ability to provide a monolithic concrete pour, but most fail to point out the added feature that that is achieved by protecting the cured concrete, from the elements that cause these structures to fail.
There are many more problems related to concrete construction, with concrete blocks and with styro foam molding blocks.
Such as the high cost of pre-cast lintels that have to be installed over any opening it some time takes two or more men to lift them into place. Some time heavy equipment is required.
The rough surface of the interior face of the C
Friedman Carl D.
Horton Yvonne M.
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