Prefabricated Masonry Walls

Abstract

A hollow prefabricated masonry wall panel is made at a fabrication site and is configured for transportation to a build site. The hollow prefabricated wall panel has a base row and an upper row formed of hollow blocks. A slit is formed in the top of each of the two side walls of the hollow blocks of the base row and upper row, the slit having a width no larger than 20% a width of a side wall. Provisional reinforcement is provided within each slit with a bonding material, a size of the slit and the provisional reinforcement configured to provide tensile strength during transportation of the hollow prefabricated wall panel from the fabrication site to the build site. At least one mid-row is laid between the base row and upper row so the hollow cavities are aligned to preserve hollow wall cavities that can accept code required reinforcement once transported to the build site.

Description

TECHNICAL FIELD

This disclosure provides a prefabricated masonry lintel in lieu of a site-constructed lintel. The disclosure relates in general to methods of making the prefabricated masonry lintel and in particular to lintels configured with provisional reinforcement allowing the lintels to be transported to a build site in a hollow form, without code-required reinforcement and grout.

BACKGROUND

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 brick masonry; stone, such as marble, granite, travertine, and limestone; and concrete block, including without limitation conventional concrete masonry units and autoclaved aerated concrete blocks. 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 code-required 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, both vertically and in horizontal channels of bond beam block. 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 or rows, 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.

SUMMARY

Disclosed herein are embodiments of prefabricated compound masonry assemblies in lieu of build site-constructed elements, and methods of producing the same.

A prefabricated masonry lintel made at a fabrication site and configured for transportation to a build site has a base row formed of U-shaped blocks laid end to end with adjacent ends adhered with mortar. A hollow horizontal cavity along a length of the base row is formed of each recess of the U-shaped blocks. A slit is formed in a top surface of each of the two side walls of the U-shaped blocks along the length of the base row, the slit having a width no larger than one-quarter inch. Provisional reinforcement is fully embedded within the slit with a bonding material different from the mortar, a size of the slit and the provisional reinforcement configured to provide tensile strength during transportation of the prefabricated masonry lintel from the fabrication site to the build site, the prefabricated masonry lintel configured to be transported with the hollow horizontal cavity having no grout and no code-required reinforcement.

A method of making a prefabricated masonry lintel that is transported to a build site from a fabrication site comprises forming a base row from U-shaped blocks, each U-shaped block having two ends, two side walls, and a U-shaped surface extending between the two side walls, the U-shaped surface being a continuous solid surface having a bottommost point below a midpoint of a height of a side wall to define a recess extending between the two side walls, wherein the U-shaped blocks are laid end to end with adjacent ends adhered with mortar to form a hollow horizontal cavity along a length of the base row. A slit is formed in a top surface of each of the two side walls of the U-shaped blocks of the base row along the length of the base row, the slit having a width no larger than one-quarter inch. Provisional reinforcement is embedded within the slit with a bonding material different from the mortar, a size of each slit and the provisional reinforcement in the base row configured to provide tensile strength during transportation of the prefabricated masonry lintel from the fabrication site to the build site with the prefabricated masonry lintel transported with the hollow horizontal cavity having no grout and no code-required reinforcement.

The prefabricated masonry lintel is transported from the fabrication site to the build site with the hollow horizontal cavity having no permanent reinforcement grouted in place. The hollow prefabricated masonry lintel is set over an opening in a wall structure and incorporated into the wall structure by adding code-required reinforcement and grout into the hollow horizontal cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views.

FIG. 1 is a perspective view of a base row of a prefabricated masonry wall panel disclosed herein.

FIG. 2 is a cross sectional view of FIG. 1 along line 2-2.

FIG. 3 is a perspective view of an embodiment of a prefabricated masonry wall panel.

FIG. 4 is a cross sectional view of FIG. 3 along line 4-4.

FIG. 5 is an enlarged perspective view of a base row or upper row to show the slit as disclosed herein.

FIGS. 6A-6C illustrate an internal lifting mechanism for the prefabricated masonry wall panels disclosed herein.

FIG. 6D is a schematic view of a prefabricated masonry wall panel being hoisted with a lifting beam.

FIG. 6E is a side view of a prefabricated masonry wall panel loaded on a means of transportation to transport the prefabricated masonry wall panel from a fabrication site to a build site.

FIG. 7 is a perspective view of a U-shaped block.

FIG. 8 is a perspective view of a prefabricated lintel showing the slits.

FIG. 9 is a side view of another embodiment of a prefabricated lintel as disclosed herein.

FIG. 10 is a cross sectional view of FIG. 9 along line 10-10.

FIG. 11 is a plan view of FIG. 9.

FIG. 12 a cross-sectional view of another embodiment of a prefabricated lintel as disclosed herein.

FIG. 13 is a schematic view of a prefabricated masonry lintel being hoisted with a lifting beam.

FIG. 14 is a plan view of a prefabricated lintel incorporating cut-outs.

FIG. 15A is a perspective view of a tool as disclosed herein to form tooled joints on inaccessible faces of prefabricated masonry lintels and walls. FIGS. 15B and 15C illustrate the tool in use and the resulting tooled joint. FIG. 15D is an alternative embodiment of the tool.

FIG. 16A is a perspective view of another embodiment of a molded U-shaped block for a prefabricated lintel, while FIG. 16B illustrates the mold used to make the molded U-shaped block. FIG. 16C is an exploded view of a molded slit.

FIG. 17 illustrates a prefabricated masonry wall panel being transported with straps.

FIGS. 18A-18D illustrate an external lifting system for use in lifting the prefabricated masonry wall panels.

FIGS. 19A-19C illustrate a guide used for positioning a prefabricated masonry wall panel onto a wall panel already placed at a build site.

FIG. 20 is a perspective plan view of the guide of FIGS. 19A-19C positioned in the already placed wall panel.

FIG. 21 is a schematic of a prefabricated masonry wall panel being positioned using guides.

FIGS. 22A and 22C illustrate a coupling guide used with the coupler of FIG. 22B to install temporary vertical reinforcement at the build site, or to install an internal lifting mechanism at the prefabrication site.

DETAILED DESCRIPTION

Prefabricated compound masonry assemblies as disclosed herein include individual concrete masonry blocks combined into wall panels, lintels and other compound masonry assemblies at a fabrication site and reinforced at specific locations within the assembly with provisional reinforcement, used specifically to provide structural support so that the prefabricated assemblies can be transported to the build site without loss of mortar or cracks in mortar joints. The provisional reinforcement for transportation provides tensile strength to the wall panels, lintel and other assemblies so that they can be lifted, transported, handled and installed at the build site. Once the prefabricated compound masonry assembly is erected at the build site, code-required vertical reinforcement, such as rebar, is inserted into the hollow cavities of the assembly and grouted in place.

Code-required vertical reinforcement is not used until the prefabricated compound masonry assembly is erected in its permanent position within a larger structure. Code-required vertical reinforcement is installed at the build site to accommodate the loadings or forces imposed on the structural elements once the overall structure is completed. The building code requires that the reinforcement be steel bars with ASTM designation A615, A706, A767, A775 or A996, and any horizontal reinforcement be steel wire meeting ASTM designation A951. The steel material has a yield strength f_fu of between 56,000 psi and 70,000 psi. The steel bar reinforcement is installed at the build site and placed vertically in the open cells or cavities of the masonry units and horizontally in the hollow, recessed horizontal cavity of a U-shaped block, and then grouted. The steel wire reinforcement is installed at the fabrication site and placed horizontally in the bed joints between the rows of blocks and mortared. The mortar and grout are cement-based materials meeting ASTM designation C270 and C476, respectively. Once mortared or grouted in place, the code-required vertical reinforcement is considered permanent reinforcement for the structure. Code-required vertical reinforcement can be described as permanent, installed at build site, steel reinforcing bars, grouted steel reinforcement, or grouted vertical bars. Code-required horizontal reinforcement can be described as permanent, and is of two kinds: steel reinforcing bars, grouted in place only at the build site; and steel wire reinforcement, mortared in place between masonry courses at the fabrication site.

As used herein, “provisional reinforcement” is distinctly different from code-required or permanent reinforcement and is installed at the fabrication site with bonding material for the sole purpose of facilitating lifting, handling and transporting prefabricated compound masonry assemblies from the fabrication site to the build site. Provisional reinforcement must have high strength to provide the tensile strength to the prefabricated compound masonry assemblies to safely support the loads imposed by lifting, handling and transporting the prefabricated compound masonry assemblies, and yet be small enough to fit within narrow slits formed in each side wall of the hollow blocks. Steel reinforcement, whether bar or wire, cannot meet both of these requirements. An example of a provisional reinforcement, without limiting other materials, is fiber reinforced polymer (FRP) in sheet (plate) or woven (⅛-inch diameter tows) configuration. This provisional reinforcement has properties such as f_fu=700,000 psi tensile (yield) strength; ε_fu=0.019 rupture strain; ε_f=0.016 design strain (85% of rupture); E_f=36,000,000 psi elastic modulus. One example of provisional reinforcement that meets these requirements is Fortec Grid™ fiber reinforced polymer. The narrow FRP (⅛ inch) has the ability to be placed in single or multiple layers in the slits in the walls of the hollow blocks and elsewhere. Provisional reinforcement can be described as temporary, installed at the fabrication site, reinforcement for transportation, or FRP or other material. Steel materials such as rebar cannot be used due to steel's lower tensile strength. A piece of steel that could provide the requisite tensile strength would need to be one inch in diameter, or two steel bars of ½-inch diameter each. Slits large enough to accommodate such reinforcement would ruin the integrity of the blocks.

FRP is not permitted by the building code for permanent reinforcement yet is approximately 10 times stronger than steel reinforcement. One ⅛-inch diameter FRP tow has the approximate strength of one ½-inch diameter steel reinforcement bar. FRP provides a unique means for serving as provisional reinforcement; steel bars would be far too large to provide the tensile strength required to lift and transport the hollow prefabricated masonry assemblies and would add significant weight to the assemblies for lifting and transporting.

Once bonded into place, provisional reinforcement is considered temporary reinforcement to facilitate lifting, handling and transporting prefabricated compound masonry assemblies from the fabrication site to the build site. Following placement of the code-required or permanent reinforcement at the build site, the provisional reinforcement can have no further utility in the assembly and in the overall structure.

“Bonding material,” used to adhere the provisional reinforcement to the masonry assemblies, is distinctly different from masonry mortar or grout. The bonding material can be epoxy resin, epoxy gel, epoxy grout or other equivalents; it is not cement-based like mortar or grout. The bonding material is selected for compatibility with the provisional reinforcement. It cannot be used to bond masonry units together. Bonding material allows the small width of the tows (⅛-inch) to be installed in a slit only 3/16″ wide; mortar could not do this. A narrow slit is necessary to limit the area of contact between the mortar used between adjacent blocks and the bonding material, minimizing any debonding that might occur between bonding material and mortar caused by applying the mortar over hardened bonding material. A narrow slit for thin provisional reinforcement has the added benefit of minimizing the amount of bonding material needed, reducing cost.

The prefabricated masonry wall panels are transported to the build site hollow and without code-required vertical reinforcement. Herein, “hollow” means that vertical openings in the prefabricated masonry wall panel are not transported with grout or code-required vertical reinforcement, leaving the vertical openings available for the code-required vertical reinforcement to be installed at the build site. At the build site, or permanent site, the prefabricated wall panels are incorporated into a building structure and have code-required vertical reinforcement, such as rebar, grouted therein. The provisional reinforcement used for transportation is not intended to, and cannot by code, replace the code-required vertical reinforcement, such as rebar, that is necessary to install at the build site to meet code requirements.

As used herein “fabrication site” refers to a site that is typically enclosed and that is a location different from the build site. The fabrication site can be any distance from the build site. The prefabricated compound masonry assemblies are built at the fabrication site and transported from there to the build site. The fabrication site is a controlled factory setting using the fabrication methods disclosed herein to produce prefabricated compound masonry assemblies that can be easily and safely transported and easily integrated into permanent building applications. This procedure uses craftsmen trained in the discipline of masonry and schooled in the new methods disclosed herein of incorporating provisional 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 at the build site when permanent code-required vertical reinforcement is installed with product quality regardless of the weather, site limitations and the natural environment.

As used herein “build site” is the site on which a structure is being built and to which the prefabricated compound masonry assemblies are transported for incorporating into the larger structure. The grouting of code-required vertical reinforcement, such as rebar, as required by building code, is done only at the build site.

The prefabricated compound masonry assemblies have many advantages over using individual blocks assembled at the build site or concrete poured at the build site. Prefabricated compound masonry assemblies will increase the speed of putting up the building at the build site. The prefabricated compound masonry assemblies are adaptable for add-ons for last minute owner requirements. The prefabricated compound masonry assemblies are built using the existing contingent of building trades. Use of the prefabricated compound masonry assemblies can eliminate work stoppage due to weather conditions and lessen site damage of the individual blocks and other components. The use of the prefabricated compound masonry assemblies can provide “ease of building” on tight or busy sites and also provide safer construction solutions.

The prefabricated compound masonry assemblies 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 mortar cement paste hardens over time, initially setting and becoming rigid and gaining in strength in the days and weeks following.

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 assemblies and their use.

The prefabricated compound masonry assemblies can be made to any overall shape and size desired or required by those skilled in the art so long as the assemblies include the requisite provisional reinforcement in the requisite sized slit to allow transportation. Examples of applications for which the use of the prefabricated compound masonry units is contemplated include but are not limited to the following: columns, walls, corners, floors, roofs, headers for doors and windows, lintels, beams, posts, ledges, wall sections, wall sections with returns, gable ends, arches, and piers.

The prefabricated compound masonry assemblies can be built on a build base 10 as seen in FIG. 1. The build base 10 is shown near but slightly raised off the ground; however, the build base 10 can be raised to any level for the comfort of the builder. However, the build base 10 does not need to be raised off the ground. The build base 10 is leveled so that the resulting prefabricated masonry wall panel 100 built on the base 10 is level. The building materials can be laid directly on the build base 10 or a base cover can be used to cover the build base 10 to prevent build-up of building materials such as epoxy and mortar on the build base 10.

One embodiment of a prefabricated compound masonry assembly is a prefabricated masonry wall panel 100 made at a fabrication site and configured for transportation to a build site as illustrated in FIGS. 1-5. The prefabricated masonry wall panel 100 comprises a base row 110 and an upper row 120, each formed of hollow blocks 40 laid end wall 17 to end wall 17 with adjacent end walls 17 adhered with mortar 42. As used herein, “mortar” refers to the typical material used by builders at a build location to adhere individual blocks together. Non-limiting examples of the mortar include mortar for unit masonry complying with ASTM C270, and ready-mixed mortar complying with ASTM C 1142. As used herein, “row” refers to two or more individual blocks combined to create a course of blocks adhered end to end. A block can be clay brick masonry; stone, such as marble, granite, travertine, and limestone; or concrete block, including without limitation, conventional concrete masonry units such as hollow stretcher blocks shown in the figures, or autoclaved aerated concrete block. Typical blocks used for wall panels are Concrete Masonry Units, ASTM C 90, except with a minimum average net area compressive strength of 3,600 psi, unless a lower strength will provide the specified masonry strength f′_m. Nominal unit sizes of 8-inch, 10-inch and 12-inch lengths with a center web on 12-inch units are typical. The minimum face shell, or side wall, thickness for units to receive provisional reinforcement for transportation is as follows:

8-inch and 10-inch lintels: 1¼ inches.

8-inch and 10-inch stretchers: 1¼ inches

12-inch lintels: 1¼ inches for face shells and center web.

12-inch stretchers: 1¼ inches for face shell.

Each hollow block 40 has a hollow cavity 43 open to a top 14 and a bottom 16 of the hollow block 40, with two end walls 17 and two side walls 18, 19 defining the hollow cavity 43. The blocks 40 in FIGS. 1-5 are stretcher blocks, with two hollow cavities per block. This is an illustration and is not meant to be limiting. The hollow blocks 40 are laid such that the hollow cavity 43 within each hollow block 40 is vertical, open to the top 14 and the bottom 16 of the hollow block 40. Each of the base row 110 and upper row 120 have a first side wall 18′ with a first top surface and a second side wall 19′ with a second top surface formed from the side walls 18, 19 and the top 14 of the hollow blocks 40.

In each of the base row 110 and upper row 120, a slit 25 is formed in the top 14 surface of each of the two side walls 18, 19 of the hollow blocks. In other words, a slit 25 is formed in the first top surface of the first side wall 18′ and another slit 25 is formed in the second top surface of the second side wall 19′ of each of the base row 110 and the upper row 120. Each slit 25 is specifically sized to receive provisional reinforcement 20 to provide the necessary tensile strength required to transport the hollow prefabricated wall panel 100. Each slit 25 can be saw cut or molded into individual blocks 40 prior to forming the row, or each slit 25 can be saw cut after the row is formed. The size of the slit 25 should be just large enough to embed the provisional reinforcement 20 in the slit 25 with bonding material 30. That is, in some embodiments, the provisional reinforcement 20 is selected so as to minimize the corresponding width of slit 25 in order to maximize the remaining surface area of top 14 surface to enhance mortar bonding. As illustrated in FIG. 5, in some embodiments, each slit 25 is formed having a depth D greater than its width W. Each slit 25 has a width W no larger than ¼″ wide when used in conventionally sized blocks. For a conventional concrete masonry stretcher block having a height H of 7⅝″ and a side wall width S of 1¼″, the depth D of the slit 25 can be ½″ while the width W of the slit 25 can be ¼″. In some embodiments where the size of the hollow blocks vary from conventional blocks, the provisional reinforcement 20 can be selected and the corresponding width of the slit 25 chosen such that the width of the slit 25 is no more than about 20% of the width of top 14 surface of the side walls 18, 19 of the hollow blocks. A non-limiting example of the dimensions of the slit 25 is ½″ deep by 3/16″ wide. Each slit 25 can extend the entire length of the respective row or can stop before longitudinal ends of each row. The slit 25 is cut across the mortared joints so that the slit 25 is continuous along the respective row. The slit 25 can be made directly along the center axis X of each side wall 18, 19.

Provisional reinforcement 20 is provided within each slit 25 with a bonding material 30 different from the mortar 42, as mortar does not meet the requirements necessary to provide the requisite tensile strength, as discussed above. As a non-limiting example, the slit 25 is filled with bonding material 30 to ¾ full. The provisional reinforcement 20 is pushed into the slit 25 until it is fully embedded in the slit 25 and completely covered with the bonding material 30. Any excess bonding material 30 on the top 14 of the block 40 is removed. Excess bonding material 30 that is not removed could interfere with the adhesion of a row of block mortared on top of the base row 110.

The provisional reinforcement 20 can come in different forms. For example, the provisional reinforcement 20 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 tows. The tows may come laced together (by Kevlar or nylon) into arrays, so that the array is one tow wide and more than one tow deep. The tows themselves are flexible and are approximately ⅛ inch in diameter. The arrays of tows can come coiled in rolls. Provisional reinforcement 20 has limited stretch, thereby providing the tensile reinforcement required when the prefabricated compound masonry assembly 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 assembly 100. However, most hollow prefabricated masonry wall panels require at a minimum provisional reinforcement 20 that is ⅛ inch wide and ¼ inch high. The remaining area of the slit 25 is filled with bonding material 30. The provisional reinforcement 20 can also be mesh or shaped FRP. The shapes can include, as non-limiting examples, tows, rods, biscuits and other joinery known to those skilled in the art. The tows, rods or biscuits can be placed along joints of adjacent blocks 40 in the slits 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.

An example of provisional reinforcement 20 meets the following minimum properties when sized to fit into the slit 25 so that lifting and transporting the hollow prefabricated wall panel is possible: f_fu=700,000 psi tensile strength; ε_fu=0.019 rupture strain; ε_f=0.016 design strain (85% of rupture); E_f=36,000,000 psi elastic modulus. These parameters provide the flexural strength and the strength to resist shear while reinforcing the hollow wall panel during lifting and transportation. One example of provisional reinforcement 20 that meets these requirements is fiber reinforced polymer by Fortec Grid™. This provisional reinforcement 20 has nearly ten times the tensile strength of code-required steel reinforcement bars. Equivalent materials that meet these requirements when sized to fit into the dimensions of the slit 25 are acceptable. The provisional reinforcement 20 can have a tensile strength f_fu of at least 500,000 psi. The provisional reinforcement 20 can extend along substantially an entire length L of the base row 110 and upper row 120. Both the slits 25 and the provisional reinforcement 20 can end just short of each end of the rows or can extend the entire length L of the rows 110, 120.

To complete the hollow prefabricated masonry wall panel 100, at least one mid-row 12 is laid between the base row 110 and the upper row 120. FIGS. 3 and 4 illustrate one mid-row 12 in the prefabricated masonry wall panel 100 as a non-limiting example. The number of mid-rows 12 is determined by the required size of prefabricated wall panel for each build project. Each mid-row 12 is formed of additional hollow blocks 40, each additional hollow block 40 having the hollow cavity 43 open to the top 14 and the bottom 16 of the hollow block 40. The hollow blocks 40 are laid end wall 17 to end wall 17 with adjacent end walls 17 adhered with mortar 42 such that the hollow cavity 43 within each hollow block 40 is vertical. The hollow cavity 43 of each hollow block 40 of the base row 110, the upper row 120 and each mid-row 12 are aligned to preserve continuous hollow wall cavities 44 that can accept the code-required vertical reinforcement at the build site. The prefabricated masonry wall panel 100 is transportable with the hollow wall cavities 44 having no grout and no code-required vertical reinforcement.

The prefabricated masonry wall panel 100 can be made with the base row 110 and the upper row 120 having a first length, and some or all of the mid-rows 12 formed intermittent along the first length to form a window, door or other opening in the prefabricated masonry wall panel 100, illustrated in FIGS. 6D and 6E.

Depending on the type and size of the prefabricated masonry wall panel 100 required, the rows 12, 110, 120 may be made of any number of hollow blocks 40. When the base row 110 is complete with the provisional reinforcement 20 retained within the slits 25 with the bonding material 30, and cured if required, a mid-row 12 is laid with mortar on top of the base row 110. One or more additional mid-rows 12 of blocks 40 can be laid and mortared as required to achieve the final dimensions of the prefabricated wall panel 100. When the number of layers is complete, the top layer is formed into the upper row 120, with additional provisional reinforcement 20 incorporated into the slits 25 of the upper row 120 as described. The prefabricated masonry wall panel 100 is limited by the maximum masonry strain not to exceed 0.0025 in./in. and the allowable strain and stress requirements of the provisional reinforcement. Minimum panel strength prior to tensioning, moving and handling is f_m=2,700 psi.

The base row 110 can be formed of blocks 40 with the slits 25 cut into the base row 110, or the slits 25 can be cut into each block 40 and the blocks 40 formed into the base row 110. The provisional reinforcement 20 is embedded in the respective slits 25 with bonding material 30, and any excess bonding material 30 is removed from the surface of the base row 110. The at least one mid-row 12 is formed on top of the base row 110. The upper row 120 can be formed of blocks 40 with the slits 25 cut into the upper row 120 after the upper row is mortared to the top of the at least one mid-row 12, or the slits 25 can be cut into each block 40 and the blocks 40 formed into the upper row 120 on top of the at least one mid-row 12.

The prefabricated masonry wall panels 100 made at the fabrication site can now be transported to the build site. Being able to transport the prefabricated masonry wall panels 100 in a hollow state, with no grout or code-required vertical reinforcement, provides flexibility to construction workers, enabling them to incorporate any number of rows. Transporting the prefabricated wall panels 100 as hollow is unique and significantly reduces the weight of the panel, allowing for lower cost and easier handling.

FIGS. 6A-6E illustrate one method for the lifting of a prefabricated masonry wall panel 100. The hollow prefabricated wall panel 100 illustrated in FIGS. 6A, 6D and 6E shows in broken line the location of the slits 25, provisional reinforcement 20 and bonding material 30. Because the prefabricated wall panel 100 shown in FIGS. 6D and 6E also has window openings, two prefabricated lintels 200, described below, are also illustrated. The prefabricated masonry wall panel 100 is built on bottom lifting plates 60, the number of which depends on the dimensions and weight of the prefabricated masonry wall panel 100 to be lifted. The bottom lifting plate 60 is metal and ⅜″ in thickness and has a width that is about one-half inch less than a width W of the prefabricated masonry wall panel 100. The bottom lifting plate 60 will double as a shim when placing the prefabricated masonry wall panel 100 on top of another wall panel, creating the required ⅜″ joint. A coupler 62 is attached to the bottom lifting plate and has a threaded open end 64. When the prefabricated masonry wall panel 100 is complete, a vertical post-tensioning bar 70 with an alignment device 66 fixed on the end is inserted through the hollow cavities 44. The alignment device 66 is inserted into a hollow cavity above the coupler 62 as illustrated in FIG. 6A, with an enlarged view of a cross-section of the alignment device 66 provided in FIG. 6C. The alignment device 66 is similar to a funnel with the neck sized to allow the post-tensioning bar 70 through it. It can be made out of plastic, for example, and is sized to move through the hollow cavity 44 of the prefabricated masonry wall panel 100. The alignment device 66 directs the coupler 62 to the post-tensioning bar 70 so that the post-tensioning bar 70 can be screwed into the coupler 62. A top plate 68 is tightened onto the post-tensioning bar 70, and the post-tensioning bar 70 is coupled to a ring 74.

To lift the hollow prefabricated wall panel 100 onto the truck 112 shown in FIG. 6E, a lifting beam 72 is connected to vertical post-tensioning bars 70 that have been fitted with rings 74 and inserted at intervals into the continuous hollow wall cavities 44 of the prefabricated wall panel 100. The post-tensioning bars 70 are removable and reuseable, and must be removed at the build site prior to the introduction of code-required vertical reinforcement. A crane is used to lift the prefabricated masonry wall panel 100 to and from the truck 112 or other means of transportation. Shoring or bracing (not shown) can be provided to the prefabricated masonry wall panel 100 after it is on the truck 112 for further protection and stabilization during travel. Other means of lifting and moving the units can be used and can be dependent on the size and weight of the unit to be transported, including the use of slings or stiffbacks.

Once at the build site, the hollow prefabricated masonry wall panel 100 is lifted from the truck 112 and placed at the build site. Once the hollow prefabricated masonry wall panel 100 is set in place in the larger structure, the post-tensioning bars 70 are removed. The bottom lifting plate 60 stays in place and acts as a shim to provide the ⅜″ joint between panels. The continuous hollow vertical wall cavities can then receive the code-required vertical reinforcement and grout.

Another way to transport the prefabricated masonry wall panel 100 is illustrated in FIG. 17. The prefabricated masonry wall panel 100 is supported by straps 80. Three straps 80 are shown, but the number of straps 80 can vary and depends on the dimensions and weight of the prefabricated wall panel 100. The straps 80 are positioned around the lifting beam 72 and the prefabricated wall panel 100 as shown. The straps 80 need to be of sufficient strength to lift the prefabricated masonry wall panels 100, which can weigh up to, for example, 10,000 pounds. If the straps 80 were simply fitted around the panel 100, they would need to be ⅜″ or less in thickness so that they do not interfere with the required ⅜″ joint when placing the panel 100 in place with other prefabricated masonry wall panels. Furthermore, the strap 80 would need to be able to be removed through an opening of ⅜″ after the panel 100 is placed. This is not feasible. Therefore, an external lifting system 400, illustrated in FIGS. 18A-18D, is used with straps 80 to allow for the ⅜″ joint and removal of the straps 80 after placement of the prefabricated masonry wall panel 100.

FIG. 18A is an end view of a prefabricated masonry wall panel 100 with the external lifting system 400 attached. The external lifting system 400 includes a top alignment support 402 and a bottom alignment support 404 and straps 406 that attach to each of the supports 402, 404. As shown in FIG. 18B, the top alignment support 402 includes a top plate 410 on which is attached a top fixed wall 412 and a top movable wall 414, both on the same surface of the top plate 410. The top plate 410 has apertures 416 in rows across the width of the top plate 410 on one side as illustrated, and the top movable wall 414 is positionable at each of the rows of apertures 416. Also attached to each end of the top plate 410 are lifting guides 418.

As shown in FIG. 18C, the bottom alignment support 404 includes a bottom plate 420 on which a bottom fixed wall 422 is attached. A bottom movable wall 424 is movably attached on the same side of the bottom plate 420. Apertures 426 are aligned in rows across the width of the bottom plate 420 used to position the bottom movable wall 424. On one side of the bottom plate 420 is a first eye bolt hole 428 through which a first eye bolt 430 is attached. Second eye bolt holes 432 are aligned with the apertures 426 and receive a second eye bolt 434.

The prefabricated masonry wall panels 100 are just that—prefabricated—so require being moved to the build site and placed. When building the prefabricated masonry wall panels 100, the bottom alignment supports 404 are placed on the build base 10 at intervals determined based on the dimensions and weight of the panel 100 to be prefabricated. As the base row 110 is laid, the blocks are aligned such that a side is positioned against the bottom fixed wall 422. When the base row 110 is complete or the panel 100 is complete, or at any time in between, the bottom movable wall 424 is positioned directly against the opposite side of the block and fixed in place with fastening means through the appropriate row of apertures 426. The rows of apertures 426 are created to provide distances between the bottom fixed wall 422 and the bottom movable wall 424 that accommodate typical concrete masonry block widths. The first eye bolt is fastened through the first eye bolt hole 428. The second eye bolt 434 is fastened through the appropriate second eye bolt hole 432.

The top alignment supports 402 are positioned on the completed prefabricated masonry wall panel 100 directly above a corresponding bottom alignment support 404. The top fixed wall 412 is positioned against a side of the panel 100 and the top movable wall 414 is positioned directly against the opposite side of the panel 100 and fixed in place with fastening means through the appropriate row of apertures 416. The rows of apertures 416 are created to provide distances between the top fixed wall 412 and the top movable wall 414 that accommodate typical concrete masonry block widths. One end of a strap 406 is attached to one of eye bolts 430, 434 and fed through a respective lifting guide 418, wrapped around the lifting beam 72, passed through the other of the lifting guide 418, with the second end of the strap 406 attached to the other eye bolt 430, 434.

Once the prefabricated masonry wall panel 100 is set in place at the build site, the straps 406 are removed, the top alignment supports 402 are removed, and the bottom movable wall 424 is removed along with the first and second eye bolts 430, 434. The bottom alignment supports 404 are slid out from the placed prefabricated masonry wall panel 100 so the external lifting system 400 can be reused. The bottom plate 10 is less than ⅜″ in thickness so that it can be slid out from under the panel 100 once in place. The top alignment support 402 and bottom alignment support 404 are made of a metal such as steel.

To assist in positioning a prefabricated masonry wall panel 100 onto another panel that is already in place at the build site, a panel stacking guide 500 can be used, as illustrated in FIGS. 19A-19C, 20 and 21. FIG. 19A is a perspective view of a guide 500 while FIG. 19B is a front view of the guide 500 positioned in and between two blocks 40 and FIG. 19 C is a side view of the guide 500. The guide 500 is hollow from top end 504 to bottom end 506. The widest section 508 of the guide 500 has a substantially flat surface 510 and is sized to friction fit within the hollow cavity or core 43 of a block 40. The widest section 508 of the guide 500 has a substantially square or rectangular circumference to friction fit in the cavity 43 of the block 40. The bottom portion 512 of the guide 500 extends from the widest section 508 to the bottom end 506 and has a first taper 520 such that the bottom end 506 has a circumference smaller than the widest section 508. The top portion 514 of the guide 500 extends from the widest section 508 to the top end 504 and has a second taper 522 on three of the walls and a third taper 524 on a fourth wall, with the second taper 522 being greater than the first taper 520 and the third taper 524 being greater than the second taper 522 such that the top end 504 has a smaller circumference than both the widest section 508 and the bottom end 506. The guide 500 also includes flanges 516 extending from opposing sides of the guide 500 just above the widest section 508. The flanges 516 are ⅜″ in thickness and extend from the guide 500 a distance that is less than the width of a top surface of a side wall 18, 19 of a block 40. The guide 500 will be left in the completed structure so is made of a material such as plastic that will keep costs low.

FIG. 20 shows the placement of the guide 500 in a cavity 43 of a block 40 of the prefabricated masonry wall panel 100. FIG. 21 illustrates the guides 500 in use. The guides 500 provide the necessary ⅜″ shim required between blocks 40, and thus prefabricated masonry wall panels 100, 100′, 100″ via flanges 516. The guides 500 guide the prefabricated masonry wall panel 100 being placed into proper flush alignment with the existing panel 100″ below. The guides 500 also allow the prefabricated masonry wall panel 100 being set adjacent to another already placed prefabricated masonry wall panel 100′ to be lowered down with a small distance between them, and assist in sliding the prefabricated masonry wall panel 100 being placed into the adjacent panel 100′ only in the last couple of inches of the descent. The first taper 520 is moderate, to assist in getting the guide 500 into the cavity 43 of the block 40 on the wall panel 100″ already in place. The second taper 522 is at a greater angle, to make it easier for the prefabricated masonry wall panel 100 being lowered to “find” the guides 500 such that the guides 500 enter cavities 43 on the blocks 40 of the panel 100 being lowered. The third taper 524 of the top portion 514 is positioned facing an adjacent, already placed wall panel 100′. This permits the prefabricated masonry wall panel 100 being set to be lowered a short distance away from the already placed wall panel 100′. A flexible gasket 526, shaped in cross-section like a plus sign, is typically fitted between two adjacent panels, with arms inserted into a vertical slot in the face of the end blocks, the sash groove 528 (shown in FIG. 17). To avoid damage to this gasket 526, it is desirable not to lower the prefabricated masonry wall panel 100 being placed while in contact with the gasket 526. The more angled third taper 524 on the guide 500 permits this.

When prefabricated masonry wall panels 100, 100′, 100″ are put in place in a building at the build site, there are times when the final internal grouting of the placed prefabricated wall panels is not possible. For example, cold weather can require postponing grouting directly upon placing a prefabricated masonry wall panel. It is necessary to brace the placed prefabricated masonry wall panels until the vertical permanent reinforcement can be grouted in place. Conventional external bracing is used. However, it may be desirable to provide at least some bracing internal to the wall panels. Temporary internal reinforcement requires long threaded steel bars be inserted into a cavity of the prefabricated masonry wall panel after it is in place in the structure being built. The threaded bar has a threaded coupler at one end that must be connected to a similar rod in the wall panel below. If the placed prefabricated masonry wall panel is at ground level, the threaded bar will need to be connected to a threaded piece at the footings. This presents the mason with the task of lowering a rod with a coupler attached down through a wall panel that may be ten feet or more tall and finding and threading the coupler onto the rod in the wall panel beneath. To assist the process, a coupling guide 600 as shown in FIGS. 22A and 22C can be used. The coupler 602 is attached to the end of the metal rod (not shown) and the coupler 602 is inserted into a receiver 604 that is sized to friction fit on the coupler 602. A stop 606 in the coupling guide 600 is sized with an opening 608 sufficient to allow a metal rod to pass. The funnel 610 has a largest diameter sized to allow for movement through the cavity of the wall panel. The metal rod is inserted into the cavity at the top of the placed prefabricated masonry wall panel 100 with the coupler 602 and the coupling guide 600 attached, and lowered to meet with the metal rod of the wall panel below. The funnel 610 directs the metal rod below into the opening 608 and to the coupler 602 so that the mason can screw the coupler 602 onto the metal rod below. When the temporary internal reinforcement is to be removed to allow for permanent vertical reinforcement and grout, the coupler 602 is unscrewed from the metal rod below and the metal rod and coupler 602 at hand are pulled out and can be reused. The coupling guide 600 is made of a material such as plastic and is disposable. If the coupling guide 600 is pulled out with the metal rod and coupler 602, it can be reused. Otherwise, it is simply grouted in place. It should be noted that the alignment device 66 and the coupling guide 600 can be the same device used for both processes.

Another example of a prefabricated compound masonry assembly is a prefabricated lintel. Lintels, for example, are typically a single row made up of a plurality of blocks to form a horizontal support across the top of a door or window opening. A prefabricated lintel would typically be transported as a single row. However, the methods herein also include adding one or more rows at the fabrication site depending on the type of unit being made.

FIGS. 7-12, 14 and 16 illustrate different prefabricated lintel designs. The prefabricated lintels incorporate the slits 25, provisional reinforcement 20 and bonding material 30 as described with regard to the prefabricated wall panels 100, so like reference numbers will be used.

A prefabricated masonry lintel 200 has a base row 150 formed from a plurality of U-shaped blocks 202, such as U-shaped solid bond beam blocks as shown in FIG. 7. Each U-shaped block 202 has a recess 207 formed from the U-shape of the block 202 between side walls 205 of the block 202. The recess 207 has a continuous solid U-shaped surface 208 extending between opposing ends 201 of the block 202 with no open cavities extending through the continuous U-shaped surface 208 of the recess 207. The continuous U-shaped surface 208 of the recess 207 has a low point Y below a midpoint X of a height H of the side wall of the U-shaped block 202, illustrated in FIG. 10.

The plurality of U-shaped blocks 202 of the base row 150 are laid end 201 to end 201 with adjacent ends 201 adhered with mortar 42. The mortar is the same as that used in the prefabricated masonry wall panels 100, so the reference number is the same. The resulting base row 150 has a continuous hollow horizontal cavity 209 that runs the length L of the base row 150.

It is desired to have tooled joints on masonry faces that are visible to the public. In the field, this can be done with a jointing tool after adjacent blocks are mortared. The tool is just pressed along the mortar joint to create a smooth, shallow curved trough between adjacent blocks for aesthetic purposes. However, this cannot be done when laying a lintel at a construction site. FIGS. 15A-15C illustrate a tool 240 for creating tooled joints 244 on the undersides of the prefabricated masonry lintels disclosed herein, providing the desired aesthetics while also providing a consistent ⅜″ joint 244. The tool 240 can be steel, wood or plastic and has a length L that is longer than a width of the blocks 202. For example, the tool 240 can be fourteen inches long. The width of the tool 240 is ⅜″ consistently along the length L to provide a consistent ⅜″ joint 244 between blocks 202. As illustrated in FIGS. 15B and 15C, from a side perspective, a first block 202 is positioned with mortar 42 on one end 201. The tool 240 is set along the end 201 on the build platform with the curved surface 246 facing up. Another block 202 is placed snuggly up against the tool 240 on the other side, creating a perfectly uniform ⅜″ joint 244 between the blocks 202. A handle 242 is incorporated at one end to easily allow the tool 240 to be slid out from between blocks 202. As the tool 240 slides out, the tool 240 creates on an otherwise inaccessible face of the lintel the desired tooled joint 244. It should be noted that this tool 240 can also be used when prefabricating the top of a window or other opening in a prefabricated masonry wall. FIG. 15D is an alternative embodiment of the tool 240′ having a different handle 242′.

In each side wall 205 of the base row 150, a slit 25 is formed in a top surface 203 of each of the two side walls 205. The slit 25 is specifically sized to receive provisional reinforcement 20 for transportation. Each slit 25 can be saw cut or molded into individual blocks 202 prior to forming the base row 150, or each slit 25 can be saw cut after the base row 150 is formed. The size of the slit 25 is important. The slit 25 is specifically sized to receive provisional reinforcement 20 to provide the necessary tensile strength required to transport the hollow prefabricated masonry lintel 200. The size of the slit 25 should be just large enough to embed the provisional reinforcement 20 in the slit 25 with bonding material 30. That is, in some embodiments, the provisional reinforcement 20 is selected so as to minimize the corresponding width of slit 25 in order to maximize the remaining surface area of top 14 surface to enhance mortar bonding. As illustrated in FIG. 8, in some embodiments, each slit 25 is formed having a depth D greater than its width W. Each slit 25 has a width W no larger than ¼″ wide when used in conventionally sized blocks. For a conventional concrete masonry stretcher block having a height H of 7⅝″ and a side wall width S of 1¼″, the depth D of the slit 25 can be ½″ while the width W of the slit 25 can be ¼″. In some embodiments where the size of the hollow blocks vary from conventional blocks, the provisional reinforcement 20 can be selected and the corresponding width of the slit 25 chosen such that the width of the slit 25 is no more than about 20% of the width of top 14 surface of the side walls 18, 19 of the hollow blocks. A non-limiting example of the dimensions of the slit 25 is ½″ deep by 3/16″ wide. Each slit 25 can extend the entire length of the respective row or can stop before longitudinal ends of each row. The slit 25 is cut across the mortared joints so that the slit 25 is continuous along the respective row. The slit 25 can be made directly along the center axis X of each side wall 18, 19.

Provisional reinforcement 20 is provided within each slit 25 with a bonding material 30 different from the mortar 42, as mortar does not meet the requirements necessary to provide the requisite tensile strength, as discussed above. As a non-limiting example, the slit 25 is filled with bonding material 30 to ¾ full. The provisional reinforcement 20 is pushed into the slit 25 until it is fully embedded in the slit 25 and completely covered with the bonding material 30. Any excess bonding material 30 on the top 203 of the block 202 is removed. Excess bonding material 30 that is not removed could interfere with the adhesion of a row of block mortared on top of the base row 150.

FIG. 9 is a side view of the base row 150 of another embodiment of the prefabricated masonry lintel 200′. FIG. 10 is a cross-sectional view of FIG. 9 along line 10-10 and FIG. 11 is a plan view of a portion of FIG. 10. As shown in FIG. 10, in addition to the slits 25 formed in the top surface 203 of the side walls 205 of the U-shaped block 202, additional provisional reinforcement 20′ is laid along the continuous U-shaped surface 208 of the continuous hollow horizontal cavity 209 and held in place with additional bonding material 30′. An upper surface 212 of the additional reinforcement 20′ and bonding material 30′ is at a height below the midpoint X of the height H of the side wall 205 so that the provisional reinforcement 20 is positioned to resist the tensile forces at the bottom of the base row 150 during transportation. The hollow space above the upper surface 212 provides sufficient hollow space at the build site to receive the code-required reinforcement in the continuous hollow horizontal cavity 209 at the build site. The upper surface 212 of the bonding material 30′ is intentionally roughened so that, when it hardens, it will bond with the grout that is placed in the hollow horizontal cavity 209 at the build site when the code-required reinforcement is installed.

The provisional reinforcement 20′ can run the length of the hollow horizontal cavity 209. It is also contemplated that the provisional reinforcement 20′ only be placed in or on the continuous U-shaped surface 208 across mortared joints of adjacent U-shaped blocks 202.

FIG. 12 is another embodiment of the prefabricated masonry lintel 200 of FIG. 8. In FIG. 12, additional slits 25′ are formed along the length L of the base row 150 in a bottom of the continuous U-shaped surface 208 of the hollow horizontal cavity 209. The slits 25 are saw cut or molded as the other slits are. Additional reinforcement 20′ is embedded in each additional slit 25′ and held in place with additional bonding material 30′. The hollow horizontal cavity 209 is preserved to accept the code-required reinforcement at the build site. The prefabricated masonry lintel 200 is transportable with the continuous hollow horizontal cavity 209 having no grout and no code-required reinforcement.

The prefabricated masonry lintels disclosed here can also be formed of molded U-shaped blocks. FIG. 16A is another embodiment of the prefabricated masonry lintel 200″ of FIG. 12 using molded U-shaped blocks. FIG. 16A is a perspective view of a U-shaped block 250 having three slits 255 formed along the length of the block 250, which in turn would extend the length of the prefabricated masonry lintel as described with respect to FIG. 12. The U-shaped block 250 also has the slits 255 formed in the top surface 260 of the side walls 265 of the U-shaped block 250 as previously described. As shown in FIG. 16B, a mold 270 is used to form both the U-shape and the slits 255 once the concrete is poured. The number of slits 255 can vary, with three shown in FIGS. 16A and 16B for illustration only. FIG. 16C is an exploded view of C in FIG. 16B, showing the dimensions of the slit 255 as previously disclosed herein. The mold 270 has ridges 272 which form the slits 255. The ridges 272 can be tapered so that, as the mold 270 is withdrawn, the ridges 272 are easily separated from the concrete to avoid pulling of the concrete and distortion of the molded slit 255. The tapered ridges 272 can taper from ¼″ at the top down to about 3/16″, for example. Using a mold rather than saw cutting can save time and create more uniform slits 255.

FIG. 13 illustrates one method for lifting of prefabricated masonry lintels disclosed herein. A broken line is used on the hollow prefabricated masonry lintel 200 to represent locations of slits 25, 25′, provisional reinforcement 20, 20′, and bonding material 30, 30′. To lift the prefabricated masonry lintel 200 onto a truck, for example, a lifting beam 172 is connected to choker slings 174 that are wrapped around the hollow prefabricated masonry lintel 200. Two or more choker slings 174 can be used depending on the length L of the prefabricated masonry lintel 200. A crane is used to lift the prefabricated masonry lintel 200 to and from the truck or other means of transportation.

To install the prefabricated masonry lintels described herein, after transporting the prefabricated masonry lintel 200 from the fabrication site to the build site with the hollow horizontal cavity 209 having no grout, the prefabricated masonry lintel 200 is placed over an opening in a wall structure and incorporated into the wall structure by adding code-required reinforcement and grout into the hollow horizontal cavity 209 of the prefabricated masonry lintel 200.

FIG. 14 is a plan view of the prefabricated masonry lintels 200′ disclosed herein having cut-outs 300 on either end 302, 304 of the lintel 200′. The cut-outs 300 can be used with any of the prefabricated masonry lintels 200, 200′, 200″ disclosed herein. The cut-out 300 is saw cut out of the bottom of the continuous U-shaped surface 208, leaving the side walls 205 intact to the end 302, 304 of the lintel 200′. The dimensions of the cut-outs 300 can vary. As non-limiting examples, the cut-out 300 can be 12″ in length A and 5″ in width B or 6″ in length A and 5″ in width B. The cut-out 300 can be the same size at each end or can be a different size at each end. The prefabricated masonry lintel may only have a cut-out 300 at one end.

The cut-outs 300 provide the following advantages. When a prefabricated lintel as disclosed herein is built at the fabrication site and transported to the build site, the prefabricated lintel is incorporated into the overall structure by setting the prefabricated lintel onto two ends of masonry columns that have had code-required vertical steel reinforcement placed into the outer edges of the masonry columns. When the prefabricated lintel is set on those columns, the code-required vertical reinforcement would be located where the bottom of the prefabricated lintel would otherwise be. By adding the cut-outs 300 to the prefabricated lintel at the fabrication site, the code-required vertical reinforcement can pass up through the cut-out 300 in the prefabricated lintel when the prefabricated lintel is placed. The cavities into which the code-required vertical reinforcement is placed get filled with grout when the code-required horizontal reinforcement is added to the prefabricated lintel at the build site. The column's code-required vertical reinforcement and the lintel's code-required horizontal reinforcement will cross one another in the end of the lintel, which of course is incorporated in the column.

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.

Claims

1. A method of making a hollow prefabricated masonry wall panel for transportation from a fabrication site to a build site, the method comprising: forming a base row from a plurality of hollow blocks, each hollow block having a hollow cavity open to a top and a bottom of the hollow block, two end walls and two side walls defining the hollow cavity, wherein the hollow blocks are laid end wall to end wall with adjacent end walls adhered with mortar to form the base row such that the hollow cavity within each hollow block is vertical;forming a lower slit in a top surface of each of the two side walls of the hollow blocks of the base row, each lower slit formed continuously along at least a majority of a length of the base row, each lower slit having a width no wider than 20% of a width of the top surface;embedding provisional reinforcement within each lower slit with a bonding material different from the mortar, such that the provisional reinforcement is flush with or below the top surface in which the lower slit is formed;forming at least one mid-row on the base row, the at least one mid-row formed of additional hollow blocks, each additional hollow block having a hollow cavity open to a top and a bottom of the hollow block, two end walls and two side walls defining the hollow cavity, wherein the hollow blocks are laid end wall to end wall with adjacent end walls adhered with mortar such that the hollow cavity within each hollow block is vertical, the hollow cavity of each hollow block of the base row and the at least one mid-row aligned to preserve hollow wall cavities;forming an upper row on top of the at least one mid-row from further additional hollow blocks laid end wall to end wall with adjacent end walls adhered with mortar to form the upper row such that the hollow cavity within each hollow block is vertical, the hollow cavity of each hollow block of the base row, the upper row and the at least one mid-row aligned to preserve the hollow wall cavities;forming an upper slit in a top surface and along a length of each of the two side walls of the hollow blocks of the upper row, each upper slit having a width no wider than 20% of a width of the top surface; andembedding additional provisional reinforcement within each upper slit with additional bonding material different from the mortar, a size of each upper slit and the provisional reinforcement in both of the base row and the upper row configured to provide tensile strength during transportation from a fabrication site to the build site of the hollow prefabricated masonry wall panel having no grout or code-required vertical reinforcement in the hollow wall cavities.

2. The method of claim 1, wherein the provisional reinforcement in each upper and lower slit is fiber reinforced polymer.

3. The method of claim 2, wherein the fiber reinforced polymer has the following properties: ffu=700,000 psi tensile strength; εfu=0.019 rupture strain; εf=0.016 design strain (85% of rupture); Ef=36,000,000 psi elastic modulus.

4. The method of claim 1, wherein the provisional reinforcement has a tensile strength of at least 500,000 psi.

5. The method of claim 1, wherein each upper and lower slit has a depth that is greater than the width.

6. The method of claim 5, wherein the depth of each upper and lower slit is one-half inch.

7. The method of claim 1, wherein the width of each upper and lower slit is 3/16 inch and a width of each side wall is at least 1¼ inches.

8. The method of claim 1, wherein each upper and lower slit is formed along a length of each of the base row and the upper row.

9. The method of claim 1, wherein the provisional reinforcement bonding material is an epoxy resin.

10. The method of claim 1, wherein the base row is formed on lifting plates having a male threaded coupler that extends into a respective hollow wall cavity, the lifting plates positioned at intervals under the base row, the method further comprising: inserting a female threaded coupler into an end of an alignment device with a friction fit, the female threaded coupler connected to a vertical post-tensioning rod, wherein the alignment device has an aperture sized to allow the male threaded coupler to pass through into the female threaded coupler;sliding the vertical post-tensioning rod into a hollow wall cavity until the male threaded coupler and the female threaded coupler meet, the funnel portion of the alignment device guiding the male threaded coupler through the aperture;screwing the female threaded coupler onto the male threaded coupler;repeating the inserting, sliding and screwing at the intervals, at least some of the post-tensioning rods having rings at a top end for connecting to a lifting member;loading the hollow prefabricated masonry wall panel onto a vehicle using the lifting member; andtransporting the hollow prefabricated masonry wall panel from the fabrication site to the build site with the hollow wall cavities containing no grout or code-required vertical reinforcement;positioning the hollow prefabricated masonry wall panel at the build site in a final position in a building being constructed;removing each vertical post-tensioning rod and attached female threaded coupler; andadding code-required vertical reinforcement and grout into the hollow wall cavities, wherein the lifting plates remain at the final position and act as scrims to provide a ⅜″ joint between the base row of the prefabricated masonry wall panel and a wall panel below.