The present invention relates in general to reinforced prefabricated compound masonry units and in particular to compound units reinforced with fiber reinforced polymer.
Structures, including residential, commercial and industrial buildings, are made from masonry using individual masonry blocks laid and bound together by mortar. The common materials of masonry construction are clay masonry such as brick and terra cotta; stone, such as marble, granite, travertine, and limestone; concrete block, including without limitation conventional concrete masonry units and autoclaved aerated concrete blocks; glass block; stucco; and tile. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the blocks are assembled can significantly affect the durability of the overall masonry construction.
Concrete masonry is a commonly used building material composed of individual blocks whose basic composition is concrete. The blocks can be hollow or solid. Concrete is strong in compression and weak in tension. For concrete that is cast at the building site, adding embedded reinforcement during pouring can provide tensile capacity. Reinforcement is not used in individual concrete masonry blocks, but masonry blocks constructed of hollow units require reinforcement at the build site to comply with building codes, and therefore receive the reinforcement at the build site as pluralities of blocks are mortared into units.
Masonry grout is similar to concrete and is poured into the hollow concrete masonry units at the build site to hold the code required reinforcement. Concrete, concrete masonry blocks, mortar, and masonry grout all contain Portland cement. Care needs to be taken to properly cure the grout and achieve the required strength. However, proper curing can be a challenge as typical build sites are outdoor areas subjected to environmental conditions that are different depending on the location and time of year.
Currently, individual masonry blocks are transported to the build site where they are laid and mortared into courses, with code required reinforcement installed as and after the courses are laid. To build a structure over about five feet in height, scaffolding is usually necessary to support the masons while they work. Weather can affect the progress of the masonry when laid on site as well.
Disclosed herein are embodiments of prefabricated compound masonry units or elements in lieu of build site-constructed elements, and methods of producing the same. One embodiment of a prefabricated compound masonry unit comprises a first course comprising a plurality of hollow blocks laid end to end with adjacent ends adhered with mortar, the plurality of hollow blocks positioned such that the first course has a hollow core; at least one channel formed in a top surface of the first course, the channel having a length; and provisional reinforcement provided along at least a portion of the length of the channel and held within the channel with a bonding material different from the mortar. The provisional reinforcement provides tensile strength to the first course for transportation and handling of the first course from a fabrication location to a build location where the first course is configured to receive permanent structural masonry reinforcement in the hollow core at the build location.
Another embodiment of a prefabricated compound masonry unit comprises a first course comprising a plurality of U-shaped blocks each having a bed extending between two side walls, the plurality of U-shaped blocks laid end to end with adjacent ends adhered with mortar and positioned to form a continuous bed along a length of the first course; and provisional reinforcement provided along at least a portion of the continuous bed of the first course and held with a bonding material different from the mortar, wherein the provisional reinforcement provides tensile strength to the first course for transportation and handling of the first course from a fabrication location to a build location where the first course is configured to receive permanent structural masonry reinforcement in a cavity defined by the continuous bed and side walls at a build location.
Also disclosed herein are methods of making a prefabricated compound masonry unit prior to transporting the unit to a building site. One such method comprises: (a) forming a first course from a plurality of hollow blocks by joining ends of adjacent blocks with mortar, the plurality of hollow blocks positioned such that the first course has a hollow core; (b) forming at least one channel in a top surface of the first course, the at least one channel having a length; (c) placing provisional reinforcement along at least a portion of the length of the at least one channel; and (d) retaining the provisional reinforcement within the at least one channel of the first course with a bonding material different from the mortar, wherein (a)-(d) are performed at a fabrication location and the provisional reinforcement provides tensile strength to the first course for transportation and handling of the first course from the fabrication location to a build location, the hollow core of the first course configured to receive permanent structural masonry reinforcement at the build location.
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
The concept of prefabricated compound masonry units reinforced with fiber reinforced polymer (hereinafter “frp”) includes individual concrete masonry blocks combined into elements (walls, beams, lintels or other masonry elements) at a fabrication site and reinforced with provisional reinforcement of frp at the fabrication site to provide structural support so that the prefabricated units can be transported to the build site and there incorporated into a building structure. The frp provides tensile strength to the units so that they can be transported, handled and installed at the build site. Once installed, the prefabricated units receive the code required reinforcement.
The prefabricated compound masonry units are provided hollow and without complete reinforcement. They have a provisional reinforcement of frp to facilitate lifting, handling, transport, delivery, and erection. The frp is not intended to replace the grouted steel reinforcement that is necessary to install at the build site to meet code requirements.
Prefabricated compound masonry units are disclosed herein that are built at a fabrication site and transported to a build site where the units are incorporated into the structure being built at the build site. As used herein, “unit” and “compound unit” refer to the use of two or more individual blocks combined to prefabricate elements at the fabrication site. A block can be clay masonry, such as brick and terra cotta; stone, such as marble, granite, travertine, and limestone; concrete block, including without limitation conventional concrete masonry units and autoclaved aerated concrete block; glass block; stucco; and tile. Compound masonry units can comprise a plurality of these blocks with one or more layers each of frp, epoxy or high strength mortar. As used herein “build site” is the location where a structure is being installed and where the prefabricated compound masonry units are assembled into the structure and further supported to meet building code requirements.
As used herein “fabrication site” refers to a site that is typically enclosed and that is a location removed from the building site. The prefabricated compound masonry units are built at the fabrication site and transported from there to the build site. The fabrication site is a controlled factory setting using the fabrications methods disclosed herein to produce prefabricated compound masonry units that can be easily and safely transported and easily integrated into field building applications. This procedure would use craftsmen currently trained in the discipline of masonry and schooled in the new methods disclosed herein of incorporating provisional frp reinforcement for strategic advantages of strength during transportation and handling. Process monitoring of the build would produce design compliance, assuring the ability of the units to meet strict code conformance with product quality regardless of the weather and the natural environment.
The prefabricated compound masonry units have many advantages over using individual blocks assembled at the build site or concrete poured at the build site. The prefabricated compound masonry units are adaptable for add-ons for last minute owner requirements. The prefabricated compound masonry units are built using the existing contingent of building trades. Use of the prefabricated compound masonry units can eliminate work stoppage due to weather conditions and lessen site damage of the individual blocks and other components. The use of prefabricated compound masonry units can also lessen occurrences of theft of product from unguarded build sites as the compound masonry units are too large to be easily transported without the proper assist and truck. The use of the prefabricated compound masonry units can provide “ease of building” on tight or busy sites and also provide safe, dust free construction solutions.
The prefabricated compound masonry units limit moisture-related shrinkage issues as the mortar will cure properly at the fabrication site and can be produced with consistent quality. Prefabricated units are manufactured in a weather-protected, controlled-temperature environment of between 60° F. and 85° F., so cold-weather protection, hot weather protection, and wind protection for masonry are not required. Cement-based materials require a moist, controlled environment to gain strength and harden fully. The cement paste hardens over time, initially setting and becoming rigid and gaining in strength in the days and weeks following. Hydration and hardening during the first three days can be critical. Fast drying and shrinkage due to factors such as evaporation may lead to increased tensile stresses at a time when the material has not yet gained significant strength, resulting in greater shrinkage cracking. During the curing period, it is preferable to maintain conditions with a controlled temperature and humid atmosphere. Properly curing concrete leads to increased strength and lower permeability, and avoids cracking from the surface drying out prematurely. Care must also be taken to avoid freezing or overheating. Improper curing can cause scaling, reduced strength, poor abrasion resistance and cracking. The methods herein address these concerns.
These advantages are provided as examples and are not meant to be limiting. Those skilled in the art will recognize these advantages and more associated with the prefabricated compound masonry units and their use.
The prefabricated compound masonry units can be made to any overall shape and size desired or required by those skilled in the art so long as the units can be transported. Examples of applications for which the use of the prefabricated compound masonry units is contemplated include but are not limited to the following: columns, decorative walls, corners, floors, roofs, footings “neat” or insulated, headers for doors and windows, lintels, beams, posts, key walls, knee walls, ledges, retaining walls, wall sections, wall sections with returns, gable ends, arches, piers and walkways.
The prefabricated compound masonry units can be built on a build base 10 as seen in
One embodiment of a prefabricated compound masonry unit is illustrated in
The bonding material 30 used to retain the provisional reinforcement 20 can be, as non-limiting examples, a high strength mortar that is a polymer modified, shrinkage compensated, rapid setting high strength, hydraulic cement-based mortar or an epoxy or epoxy grout. Similar materials known to those skilled in the art are also contemplated. The bonding material 30 is to be distinguished from adhesive material such as mortar typically used to adhere blocks to one another in masonry or grout used in other applications. Ordinary mortar or grout would not suffice for holding the provisional reinforcement 20 to the course 12 during transportation, handling, etc. of the prefabricated unit. Additionally, it would not be feasible to simply substitute the bonding material 30 used to retain the provisional reinforcement for traditional or ordinary mortar between blocks, as the bonding material 30 would be prohibitively expensive and lack the viscosity to hold together the blocks of the units in the same way mortar does.
Provisional reinforcement 20 is frp and includes, as non-limiting examples, carbon fibers or aramid fibers which are set in the bonding material. The provisional reinforcement can come in different forms. For example, the provisional reinforcement can come in plate form. The plate is a somewhat stiff yet still flexible sheet, i.e., it will spring back after it is flexed. The plate is cut into strips for use as the provisional reinforcement. As another example, the provisional reinforcement can come in the form of toes. The toes come laced together (by Kevlar or nylon) into arrays, so that the array is one toe wide and more than one toe deep. The arrays are cut to the number of toes needed for a particular application. The toes themselves are flexible and are approximately 1/8 inch in diameter. The arrays of toes come coiled in rolls. Provisional reinforcement 20 has limited stretch, thereby providing the reinforcement required when the prefabricated compound masonry unit 100 is lifted, transported, etc. The amount and configuration of the provisional reinforcement will change depending on one or more of the dimensions, weight, lifting configuration and application of the resulting prefabricated compound masonry unit 100. Other embodiments of the provisional reinforcement 20 are contemplated. For example, the provisional reinforcement 20 can be mesh or shaped frp. The shapes can include, as non-limiting examples, dowels, biscuits and other joinery known to those skilled in the art. The dowels or biscuits can be placed along joints of adjacent blocks 40 in the channels 25 if provided, in existing openings in the individual units or in apertures cut into the individual units specifically to receive the shaped frp. The type and shape of frp used can depend on the type of hollow block used.
As seen in
Depending on the type and size of unit required, the course 12 may be made of any number of blocks 40. Lintels, for example, are typically a single course 12 made up of a plurality of blocks 40. A prefabricated lintel would typically be transported as a single course. However, the methods herein also include adding one or more courses at the fabrication site depending on the type of unit being made.
It is also contemplated that provisional reinforcement 20 and bonding material 30 can be used between one or more layers as required to assure the prefabricated compound masonry unit 110 has the necessary strength.
As non-limiting examples, the provisional reinforcement 20 can extend along at least a portion of both the first side 18 and the second side 19 of one or both of the bottom surface 16 and top surface 14 of one or more of the courses 12 that form a unit and be held with bonding material 30. The provisional reinforcement 20 can extend along substantially an entire length L of the course 12 or can extend at intervals along the course 12. The prefabricated compound masonry unit 110 can have a plurality of courses 12 having a lowermost course and an uppermost course with the first side 18 and the second side 19 of the top surface 14 of each of the lowermost course and the uppermost course having the channel 25 formed therein, with the provisional reinforcement 20 retained within each channel 25 with the bonding material 30.
The bonding material 30 can be installed in the channels 25 before laying the provisional reinforcement 20 in the channel 25 and/or after laying the provisional reinforcement 20 in the channel. The bonding material 30 is cured as required.
The prefabricated compound masonry units 100, 110 are made at the fabrication location in any number of courses to be transportable to a build site without having all of the horizontal and vertical reinforcement that is necessary to meet building code requirements. The provisional reinforcement provided in the units at the fabrication location provides tensile strength (i.e., flexural strength and strength to resist shear) to the units only to enable transportation and handling of the hollow courses to a build site. “Hollow” refers to the fact that not all of the reinforcement required for a code-compliant, completed building has yet been incorporated into the units. Being able to transport the units in a hollow state provides flexibility to construction workers, enabling them to incorporate any number of courses as needed into the structure, such as a single course, also referred to as a lintel. Transporting the courses as “hollow” is unique and significantly reduces the weight of the courses, allowing for lower cost and easier handling. It also permits the steel reinforcement required for a completed building to be installed only when the prefabricated element is incorporated in the structure at the build site. This in turn permits the steel reinforcement to be continuous through the prefabricated element and the structure into which it is incorporated, which offers significant structural (statics) advantages.
The layers 206, 212 of bonding material 30 and provisional reinforcement 210 can run the length of the compound masonry unit 200. It is also contemplated that at least the provisional reinforcement 210 only be placed in the bed 208 across the joints of individual units 202. Alternatively, the provisional reinforcement 210 can be laid in multiple sections in any suitable lengths and any suitable interval that provide the requisite strength to the compound masonry unit 200.
In another embodiment, provisional reinforcement 210 can be added to the compound unit 200 to bridge the joints 211 between individual blocks 202 at the top of the course, as shown in
Another embodiment of the compound unit 200′ is shown in
In this embodiment, provisional reinforcement 210 is added to the compound unit 200′ to bridge the joints 211 between individual blocks 202 at the top of the bottom course 201, as well as to bridge the joints 211 between individual blocks 40 at the top of the second course 203. The provisional reinforcement 210 is set in slots with bonding material 30. As with
The embodiment of
The layers 206, 212 of bonding material 30 and provisional reinforcement 210′ can run the length of the unit 200′. It is also contemplated that at least the provisional reinforcement 210′ only be placed in the bed 208 across the joints of individual units 202′. Alternatively, the provisional reinforcement 210′ can be laid in multiple sections in any suitable lengths that provide the requisite strength to the compound unit.
Also illustrated in
As shown in
In the embodiments described herein, a coating can be applied to the compound masonry units prior to transporting to the build site to provide corrosion protection and abrasion resistance and fills joints. The coating can be, as a non-limiting example, a polymer coating that uses formulations of poly urea with different physical property ranges. A coating can also be used to water proof the compound masonry units as desired or required. One skilled in the art will recognize the various coating that can be used to achieve the desired results.
While the invention has been described in connection with certain embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as are permitted under the law.
This application is a continuation-in-part of U.S. patent application Ser. No. 13/307,704 filed on Nov. 30, 2011, which is a continuation application of U.S. patent application Ser. No. 13/274,502 filed on Oct. 17, 2011, which claims priority to U.S. Provisional Patent Application Ser. No. 61/393,599 filed on Oct. 15, 2010 and U.S. Provisional Patent Application Ser. No. 61/439,863 filed on Feb. 5, 2011, all of which are incorporated herein in their entirety.
Number | Date | Country | |
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61439863 | Feb 2011 | US | |
61393599 | Oct 2010 | US |
Number | Date | Country | |
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Parent | 13274502 | Oct 2011 | US |
Child | 13307704 | US |
Number | Date | Country | |
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Parent | 13307704 | Nov 2011 | US |
Child | 13846470 | US |