Abstract:
A masonry block and hardware set for constructing dry stack walls and columns, including a wall unit, a corner unit, and an end unit, wherein each of the wall, corner, and end units have a top surface with a depression that is brought into substantial alignment when an adjoining block at the same level or in the same course is abutted with the respective unit, and further wherein when any two of the units are adjoined, the units create a vertically oriented space for accommodated clamping hardware, and further wherein each of the end and corner units include an alignment slot to align the end units and the corner units in relation to adjoining wall units. Clamping hardware is employed to bolt the wall while construction proceeds, the hardware being disposed in the masonry unit depressions and in the vertically oriented space created by stacked units. The clamping provides a downwardly directed compressive force and lateral rigidity.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The present application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 61/239,659, filed Sep. 3, 2009 (Sep. 3, 2009). 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     THE NAMES OR PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not applicable. 
     SEQUENCE LISTING 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to monolithic block-shaped wall construction units, such as masonry blocks, and more specifically to an improved stackable wall and column construction units adapted for use in constructing dry-stackable structures. 
     2. Discussion of Related Art Including Information Disclosed Under 37 CFR §§1.97, 1.98 
     The art of building dry stack stone walls is ancient and therefore highly developed. Even so, due to the high cost and difficulty of constructing walls of quarried stone or block, cast cementitious blocks long ago replaced quarried stone as a preferred material in many applications. 
     Cast blocks typically have a uniform size and shape, include at least one cavity, and frequently permit physical interlocking, either vertically or horizontally, with physical elements frequently integrally formed in the blocks. Such interlocking designs facilitate rapid assembly and proper alignment during fabrication. They also permit assembly without mortar, so that some designs of cast blocks may be employed for temporary walls that can be easily disassembled. 
     Dry stacked walls constructed of cast blocks may rely exclusively on the mass of the stacked blocks to maintain alignment and stability. However, mortarless cementitious cast block walls intended for permanent use usually require additional stability. Accordingly, many designs permit mortar or reinforced concrete to be poured or injected into and to fill gaps and aligned vertical and horizontal openings in the blocks. 
     However, along with their advantages, the known cast blocks also have many disadvantages, including: difficulty in converting the wall units into end or corner units; lateral instability; vulnerability of exposed mortar to chemical or environmental degradation; expansion and contraction of mortar, causing cracking and separation of blocks; difficulty in constructing curved configurations; and vulnerability of broad flat surfaces to defacement and graffiti. 
     Accordingly, the inventor of the present invention devised a mason wall cementitious building block system that is the described in U.S. Pat. No. 6,205,735, which is incorporated in its entirety by reference herein. The system disclosed therein comprises a wall and a corner unit making up a lightweight dry-stackable block unit system. Both wall units and corner/end units connect one to another in an interlocking fashion. The unit shapes and the method of assembling walls using such units provided several solutions to the problems then present in the prior art. 
     However, the improved block of the &#39;735 patent was adapted for use with steel reinforcement bar and poured in concrete for structural stability and as a means to resist displacement of the stacked stones. This made any wall built with the inventive system necessarily permanent and essentially impossible to change or modify after and during construction without damaging the block material. Additionally, wall construction required labor skilled in the masonry and concrete trades. 
     The present invention represents a dramatic improvement over the technology described in the &#39;735 by providing a simplified block that nevertheless provides equivalent structural integrity when dry stacked, but requires no interlocking pieces. Further, the inventive system employs a novel hardware system that facilitates rapid dry stack construction while providing significantly enhanced strength and stability over prior art designs. 
     BRIEF SUMMARY OF THE INVENTION 
     The inventive dry stack block units and hardware system for constructing walls using the block units is designed to provide an aesthetically appealing, upscale brick or block landscaping wall. The walls may be erected as freestanding fencing or as low retaining walls of four feet or less in height. The improved block design cooperates with a truly unique hardware system that creates an economical and simplified system for bolting the wall together as it is erected. The wall may be built upon and bolted to a poured-in-place concrete footing, which may be engineered for various heights and applications with site specific-conditions, or it may be built on a simple footing so as to enable a thorough dry stack construction and thereby allow post construction modification or wholesale dismantling. 
     It is a principal object of the present invention to provide a new and improved dry-stack masonry building unit which simplifies and reduces the cost of mold design. The simplification has downstream effects of creating cost savings in the initial mold construction, extending the life of the mold, and yielding improved production results with fewer defects and rejected units. 
     Another object of the present invention is to provide an improved dry-stack building unit that simplifies wall construction by eliminating any need for the use of interlocking units and which requires only that the units be butted together. This saves time and effort and reduces damage to the block units during construction. 
     A further object of the present invention is to provide a simplified block design that minimizes unit breakage from shipping and handling and facilitates stacking and transportation on pallets. 
     A still further object of the present invention is to provide an improved building unit designed for use with an inventive hardware system that enables the units to be quickly and easily bolted together in a more secure and economical assembly, while also facilitating unit easy and efficient means to align spacing the blocks. 
     Another object of the present invention is to provide a new and improved dry-stack masonry unit and system for using the same, wherein block cutting is minimized and need only be done in laying wall units in connection with corner units. 
     Yet another object of the present invention is to provide an improved dry-stack building unit in which wall construction is accomplished by stacking and bolting block units without the need for mortar. This is accomplished through the use of a novel hardware system, wherein a unique galvanized sheet metal bond strap provides three distinct and important structural and commercial advantages over conventional masonry assembly: First, the bond strap ties a wall system together, from end to end or from corner to corner. Second, it helps to align and space the individual building units, inasmuch as the bond strap fits snugly into the recessed area in the top of each unit. Third, it enables intermittent bolting of the wall assembly, and this greatly facilitates the assembly process, as well as providing greater seismic and structural stability. Other hardware elements, including a bolt plate, end ties, and corner ties, are an extension of the inventive bond strap concept and provide a novel fastening system for mortarless masonry. The novel hardware solves the problem of needing to manufacture the building units at minimal expense using standard and readily available equipment while also producing a stackable unit that can be assembled easily by unskilled laborers. 
     The objects and advantages set out above are achieved by providing a building unit and system of constructing walls and columns employs three principal blocks for the system, including a wall unit, a corner unit, and an end unit. Each have a simple shape that presents a clean outline for each wall, end and corner unit. The blocks are provided with depressions on their top sides that are instantly brought into substantial alignment when the blocks are abutted. The depth and area of depression in the top of each block unit then receives above-mentioned hardware for clamping the units in place as the construction proceeds. The clamping provides a downwardly directed compressive force and introduces lateral rigidity. The inventive design also incorporates a narrow slot stamped into the top of each unit which is used to secure permanent alignment of the end and corner units. 
     The improved block design may be provided in a wide range of standard sizes—e.g., four, six or eight inches in height—and may have various front surface contours, including split face, fluted or ribbed finishes. The units may be employed in either running bond or stacked bond assemblies. 
     The foregoing summary broadly sets out the more important features of the present invention so that the detailed description that follows may be better understood, and so that the present contributions to the art may be better appreciated. There are additional features of the invention that will be described in the detailed description of the preferred embodiments of the invention which will form the subject matter of the claims appended hereto. 
     Accordingly, before explaining the preferred embodiment of the disclosure in detail, it is to be understood that the disclosure is not limited in its application to the details of the construction and the arrangements set forth in the following description or illustrated in the drawings. The inventive apparatus described herein is capable of other embodiments and of being practiced and carried out in various ways. 
     Also, it is to be understood that the terminology and phraseology employed herein are for descriptive purposes only, and not limitation. Where specific dimensional and material specifications have been included or omitted from the specification or the claims, or both, it is to be understood that the same are not to be incorporated into the appended claims, which will be presented at the time of filing a non-provisional patent application based on the instant application and claiming the benefit of its priority date. 
     As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based may readily be used as a basis for designing other structures, methods, and systems for carrying out the several purposes of the present invention. 
     For a better understanding of the present invention, its advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated the preferred embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
         FIG. 1  is an upper perspective view top plan view showing a wall as constructing using the inventive dry-stack block units and hardware elements of the present invention; 
         FIG. 2  is a top plan view of the primary monolithic block employed in the dry stack system of the present invention; 
         FIG. 2A  is a bottom view thereof; 
         FIG. 3  is a top plan view of a corner block used in the inventive system; 
         FIG. 4  is a top plan view of an end block; 
         FIG. 4A  is a bottom view thereof; 
         FIG. 5  is a top plan view of the bond strap of the hardware system of the present invention; 
         FIG. 5A  is an upper perspective end view thereof; 
         FIG. 5B  shows how the tabs of the end of the bond strap can be bent upwardly or downwardly to engage the end blocks in a course of blocks; 
         FIG. 6A  is an upper perspective view of a steel bolt plate used in combination with bond straps and vertical support rods in the hardware system of the present invention; 
         FIG. 6B  is an alternative bolt plate fabricated from sheet metal; 
         FIG. 7A  is a top plan view of a corner plate; 
         FIG. 7B  is a top perspective view showing an intact corner plate with tabs bent for installation in the slots of corner units assembled as a column; 
         FIG. 7C  is a top perspective view showing the corner plate of  FIGS. 7A-B  split into two halves; 
         FIG. 7D  is a top perspective view showing the corner plate of  FIG. 7C  with the corner tabs bent for insertion in block unit slots; 
         FIG. 7E  is a top plan view showing a column assembly before the installation of the corner plate of  7 A; 
         FIG. 7F  shows the column of  FIG. 7C  after installation of the intact corner plate of  FIG. 7A ; 
         FIG. 7G  shows an alternative bolt plate; 
         FIG. 7H  shows an alternative corner plate; 
         FIG. 8  is a top plan view of an end tie strap; 
         FIG. 9A  is a top plan view of a column bolt plate; 
         FIG. 9B  is a top plan view of a corner el that may used instead of the corner unit of  FIGS. 7A-D  to secure a corner unit in a wall; 
         FIG. 10  is an upper left perspective view showing an assembled hardware layout for a typical six-foot high wall using the principal hardware elements employed in the inventive dry-stack masonry system of the present invention; 
         FIG. 11A  is a top plan view showing the block and hardware configuration for a the interior portions of a simple wall; 
         FIG. 11B  is a bottom plan view thereof; 
         FIG. 11C  is an upper perspective end view showing the inventive hardware installed over a single course in a wall under construction; 
         FIG. 12A  is a top plan view of the block and hardware configuration for two walls joined at a 90 degree corner; and 
         FIG. 12B  is a bottom view of the adjoining walls of  FIG. 12A . 
     
    
    
     LEGEND 
       FIGS. 1-4 , Building Units: walls  10 ,  12 , 90 degree corner  14 , wall unit  16 , end unit  18 , corner units  20 . 
     Wall unit  16 : front face  22 , front face width  24 , back side  26 , depth  28 , angled sides  30 ,  32 , rounded corners  34 ,  36 , male body portion  38 , central region  40 , center line  42 , wings  44 ,  46 , female body portion  48 , base portion  50 , distal portion  52 , concavities  54 ,  56 , top surface  58 , depression  60 ,  62 , depression  64 , rear face  66 . 
     Corner unit  20 , front face  70 , inboard side  72 , rear side portion  74 , rear side portion  76 , projection  78 , surface  80 , outboard side  82 , slot  84 , main body  86 , rounded corner  88 , wing  90  female concavity  92 . 
     End unit  18 , front face  100 , outside face  102 , recess  104 , rear face  106 , wing  108 , angled side  110 , rear side  112 , outside face  102 , rounded corner  114 , triangular projection  116 , first recessed area  118 , second recessed portion  120 , slot  122 , female concavity  124 . 
     FIGS.  5 - 12 B—Hardware: Bond strap  130 , hole  132 , tab  134 , bends  136 . 
     Bolt plates  140 , holes  142 ,  144 , metal plate  146 , hole  148 , partial hole  150 , thread-capture cut  152 . 
     Corner bolt plates  160 , diagonal slots  162 ,  164 , right triangle halves  166 ,  168 , bolt holes  170 , center hole  171 , crimps or cuts  172 , diagonal corner cuts  174 , corners  176 , tabs  178 . 
     End tie straps  180 , holes  182 , tabs  184 . 
     Column plates  190 , center hole  192 , tabs  194 . 
     Alternative corner plate  195 , bolt holes  196 , end cuts  197 , corner cut  198 , tabs  199 , anchor bolts  200 , concrete footing  202  space between back sides of units  210 . 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 through 12B , wherein like reference numerals refer to like components in the various views, there is illustrated therein a new and improved dry stack masonry system. 
     BLOCK UNITS: The inventive cementitious blocks and system for constructing walls using the same comprises, in the first instance, a unique combination of monolithic wall, corner, and end units. Two walls  10 ,  12 , joined at a 90 degree corner  14 , using the inventive system are shown in  FIG. 1 . As will be immediately appreciated from this view, a wall so constructed comprises three block units, including wall units  16 , end units  18 , and corner units  20 . 
     Referring now to  FIGS. 2-2A , there is shown in schematic form a top plan view of the principle wall unit  16  of the inventive dry stack masonry block system. The wall unit includes a front face  22  having a front face width  24 , a back side  26  and a depth  28  defined as the distance from the front face to the back side; and two angled sides  30 ,  32 , each of which angle outwardly from the front face to join the back side at a rounded corner  34 ,  36 . Collectively, these elements form a male body portion  38  having a central region  40  with a center line  42  bisecting the block into identical first and second halves. Two generally triangular wings  44 ,  46 , each defined by an angled side and the rear side, extend outwardly from the central region. A female body portion  48  integrally formed in the monolithic block extends rearwardly from the central region of the male body portion and includes a base portion  50 , a distal portion  52 , and two concavities  54 ,  56 , disposed between the base and distal portions and shaped to conform to and accommodate the corner of a male wing (with generally tight tolerances) in a block in a reverse orientation. It should be noted that only the top side of the units include recesses or depressions, as the bottom side of the blocks is preferably substantially planar. 
     Next, the wall unit includes a top surface  58  covering all portions and including a rectangular shaped depression  60 ,  62  in the surface of the rear area of each wing and a depression  64  on the entire surface of the base area. The depth of the depressions in the wings is greater than that of the depression in the base portion, in that the former accommodates a bolt plate and is disposed underneath a bond strap when installing the hardware system for connecting and securing the units. These elements are described in detail below. 
     Finally, the wall unit includes a rear face  66 , which is disposed between the angled sides of adjoining blocks in a constructed wall. 
     Referring now to  FIG. 3 , there is shown the corner unit  20  of the inventive dry stack masonry system. The corner unit includes a front face  70 , and angled inboard side  72 , a flat rear side portion  74 , a triangular rear side portion  76 , and a projection  78  extending rearward from the rear side and disposed between the flat rear side portion and the triangular rear side portion and having a surface  80  depressed to the same depth as the depressions  60 ,  62  in the wall unit. Opposite the angled inboard side  72  is a flat outboard side  82  which is substantially normal to the front face  70 . A slot  84  is cut into the main body  86  of the block and extends into the projection  78  so as to accommodate a bend in the bond strap of the hardware. As with the wall unit, the corner unit includes an angled side that joins the rear side in a rounded corner  88  and the geometry defines a wing  90  for insertion into a female concavity in an adjoining block. Additionally, disposed between the projection  78  and the triangular rear portion  76  is a female concavity  92  shaped and sized to accommodate (with tight tolerances) the corner of a wing of a block disposed generally normal to the corner unit. 
     Next, and referring now to  FIGS. 4-4A , there is shown an end unit  18 , which includes a front face  100  (preferably flat), and outside face  102  (preferably contoured and including a trough-shaped recess  104  shaped to generally match in appearance to the recesses between the front faces of adjoining blocks in a constructed wall), and a rear face  106 . A wing  108  is defined by an angled side  110  and a flat rear side  112  that is generally perpendicular to the outside face  102 . The angled side and flat rear side join in a rounded corner  114 , which, again, fits into a female concavity of an adjoining block. disposed between the wing and outside face  106  are a triangular projection  116 , a first recessed area  118  for cradling the end of a bond strap, and a second recessed portion  120  for accommodating an edge of a bolt plate. The first recessed area terminates in a slot  122  which accepts a bent end of a bond strap. Disposed between the first depressed area  118  and the triangular projection  116  is a female concavity  124  matching its counterparts in the wall and corner units. 
     Hardware: The unique hardware system of the present invention minimally includes: (a) anchor bolts; (b) bond straps; (c) bolt plates (including corner bolt plates); (d) end tie straps; and (e) column plates. 
     The above-referenced anchor bolts are shown in an assembled hardware layout in  FIG. 10 . Such J-bolts are well known in the art. For use in the present invention, they preferably comprise standard, off the shelf, ⅝″ or ¾″ diameter, 27-30″ length, right angle bend anchor bolts, all thread rods and nuts. 
     The bond strap  130  is shown in  FIGS. 5-5B , and preferably comprise an elongate, rectangular galvanized sheet metal bond strap, 1½″×113″ straps of 16 gauge to 10 gauge thickness and having a pre-punched hole  132  and tab  134  pattern, the latter to form bends  136  for insertion into slots in blocks. 
     Next, and referring now to  FIGS. 6A-8 , the hardware system includes bolt plates  140 , which preferably comprise 3″×3″×⅜″ plates with one punched 11/16″ diameter hole  142  and one drilled and threaded standard ⅝″×11 hole  144 . Alternatively, and referring now  FIG. 6B , the bolt plate may comprise a 3″×3″⅛″ gauge sheet metal plate  146  with an 11/16″ hole  148 , and a partial hole  150  with a thread-capture cut  152 . 
     Referring now to  FIGS. 7A-D , corner bolt plates  160  comprise a ⅛″ gauge sheet metal square with diagonal slots  162 ,  164 , which facilitate breaking the plates in half to form two discrete right triangle halves  166 ,  168 . Each half includes pre-drilled holes  170  for passing bolts, a center hole  171 , crimps or small cuts  172  and diagonal cuts  174  at the vertices  176  of each triangle so as to form tabs  178  that enable easy bending of the corners for insertion into corner unit slots. In a manner well known in the art, slots  173  disposed on the diagonal and having bridges disposed therebetween define frangible lines and provide means for weakening the plate for breaking it into the halves described above by bending the plate along the diagonal line defined by the slots. 
       FIG. 7E  is a top plan view showing a column assembly before the installation of the corner plate of  FIGS. 7A-D .  FIG. 7F  shows the column of  FIG. 7E  after installation of the intact corner plate of  FIG. 7A . The tabs  178  are bent for insertion into alignment slots  84  and anchor (or threaded extension bolt)  200  is disposed through center hole  171 . The bolt holes  170  are shown arrayed alongside cuts  173 . 
     Alternative corner plate configurations are possible, as is shown in  FIG. 7G . In this bolt plate design  160 B, fold up/fold down tabs  178   b  are provided by slots  172   b  that facilitate folding for insertion either up or down into alignment slots according to the orientation of the stacked units in the particular bolting course. This plate also includes an alternative arrangement of bolt holes  170   b.    
       FIG. 7H  shows still another alternative corner plate  160 C. This design is used only on bond strap courses and includes a rectangular body portion  160   c  with two triangular end portions  161   c , each having an end vertex  162   c  with a 90 degree angle joining two sides  163   c  each angled 45 degrees relative to their respective outside edges  165   c . This singular hardware piece is positioned in the same way that the triangular plate of  FIGS. 7C-7D  is positioned. Punched bolt holes  170   c  are positioned on the longitudinal centerline on each side of the transverse midline  175   c . A triangular cut  176   c  on one side at the midline facilitates placement toward the inside portion of a corner (closest where the masonry unit sides converge). 
     Next, and referring now to  FIG. 8 , the hardware system includes elongate end tie straps  180 , preferably 1½″×8¼″×16 gauge galvanized sheet metal end straps with pre-punched holes  182  disposed longitudinally along a center line, and tabs  184  for ends and corners. 
     Next, as seen in  FIG. 9A , the hardware system includes column plates  190 , preferably 5 7/16″×10 gauge square galvanized sheet metal plates with a pre-punched center hole  192  and tabs  194  disposed on each side proximate a corner. 
     Finally, as seen in  FIG. 9B , it will be clear that an alternative to the corner plates shown in  FIGS. 7A-D  may be employed. This comprises a simple plate el  195  may be employed for securing corner units to wall units in an assembly. The el includes bolt holes  196 , and may further include end cuts  197  and a corner cut  198  for forming tabs  199  suitable for insertion in block slots, as needed. Use of this el obviates the need to carve a recess in the wall unit, as is required when using the corner plate, as shown in  FIG. 12A . 
     As can be seen by reference to  FIG. 1  and  FIGS. 11-12B , the fundamental stacking orientation of adjoining blocks in any given course is simply end-to-end abutment. That is, the blocks are merely pushed together into an abutting relationship by sliding the wing of one block into the female concavity of an adjoining block, at which point they cannot be further approximated. If both blocks are wall units, each block “interlocks” with the other inasmuch as a wing of each block is inserted into a female concavity of the adjoining block. With the wall units in this orientation, they also cannot be translated radially, i.e., rotated, and this prevents gross misalignments or an accumulation of successive small misalignments that add up to a grossly misaligned wall. However, the blocks (at least when looked at as simple pairs) could possibly be separated by translating them laterally, which is to say, apart. Furthermore, end and corner units may still be subjected to radial translation, and this is where the inventive hardware plays its essential role. 
     The hardware system employed in the present invention provides structural integrity where it is needed the most, namely, the lower portion of the wall. At the same time it still provides the flexibility of eliminating the cost and time required to employ all of the structural elements the full height of the wall. One unique feature of the hardware system is that it enables users to bolt the lower courses of blocks on a different spacing schedule than the higher courses of blocks. For instance, bolts can be provided every eight inches on center, if needed for the lowest course or courses, but bolts can be placed at 16 inches on center in the middle courses, and 32 inches on center for the highest courses. Accordingly, for the smaller brick designs, anchor bolt spacing can begin as tight as eight inches on center and progress to sixteen or thirty-two inches on center, if desired. For larger block designs, spacing can begin at twelve inches on center and progress to twenty-four or forty-eight inches on center. 
     The hardware system further ensures unit alignment front to back while tying the wall from end to end at a predetermined height (e.g., every two feet in height) as the wall units are stacked. This method permanently secures the units at reasonable intervals for ease of construction. 
     A differential spacing schedule for vertical anchor bolts can be seen in  FIG. 10 , which shows the kind of grid-like scaffolding that the anchor bolts  200 , bond straps  130 , and bolt plates  140 / 146  provide when erected atop a poured-in-place concrete footing  202 . The means for securing anchor J-bolts in a concrete wall footing is well known in the art and need not be described herein. Upper courses of bolts are simply inserted straight end first through the bolt hole of a lower bond strap and then through the bolt hole in the bond strap immediately above and secured with a nut until the bend in the anchor engages the lower bond strap. 
     Construction Method: What follows is a more detailed explanation of the method steps in constructing a wall using the novel blocks shown in the instant application. 
     Footing: As may be surmised from the foregoing description of the system units and hardware, the inventive masonry wall system preferably rests upon a poured-in-place concrete footing. The width and depth of this footing will vary with the height and function of the wall. Free standing landscape fencing will require a lesser footing than a retaining wall of the same height, but in either case the inventive dry stack system is not intended to exceed more than six feet in height. However, standard engineering of the footing design may be provided for given wall heights with site-specific engineering provided by a qualified structural engineer. 
     Wall layout, footing size and elevations are determined in advance of excavation. Once below grade footing excavations have been completed, long reinforcing steel with stirrups, if required, should be laid in the bottom of the footing on wire chairs, such as Simpson Strong Tie WRC3. 
     The inventive dry stack system preferably sits on an eight inch wide curb. Anchor bolt layout may be provided pursuant to engineering specifications. The brick design may have anchor bolts as close as eight inches on center, and this close schedule may be required for some retaining wall. In every instance, the anchor bolts are placed according to the available spacing of the pre-punched holes in the bond strap. 
     Preferably the concrete footing has a curb height at finish grade and requires only that the top of the curb be struck off level for finishing. Anchor bolts are held plumb and to the correct height, viz., one inch minimum above the first prescribed bond strap height. Anchor bolts are embedded at a depth of at least the bottom reinforcing steel. 
     First Course: After the concrete footing has cured and any form work removed, the first course can be laid out. Surface irregularities or debris, such as pebbles. on the top of the curb are removed. Beginning at one end or corner, the terminal unit is placed followed by wall units alternating front to back until the opposite end is reached. The first course of wall units is laid with the top side down, thus presenting a generally planar surface on which the second course will be laid. With the recessed areas down these units will face fewer irregularities. Wall units mate to interlock around the anchor bolts with the rounded corner of one block inserted into the female concavity of an adjoining block such that a space  210  is defined between the back sides of adjoining blocks, and it is through these spaces that the vertically disposed anchors bolts extend. See  FIGS. 11B and 12B . 
     When the opposite end or corner of the wall is reached, the end or corner unit is placed with the top either up or down so that it mates with the last wall unit. A dry line is pulled from end to end and the original layout marks the height of the block above the curb. Wall alignment is checked using the dry line from end to end and from front to back with a good hand level. Adjustments are made as needed and two to four courses are stacked at each end tapering down, as if building the wall from the ends toward the center. 
     In the event the wall cannot be adjusted to level properly from front to back, triangular shims of twenty four gauge galvanized sheet metal can be used on the low side. These one and one half right angle shims can be placed adjacent the anchor bolt where the bearing area provides the greatest cross sectional overlap. Voids larger than a few thicknesses are preferably filled with mortar. 
       FIGS. 12A-12B  show how corner units  20  are abutted to adjoining wall units  16 , and how the inventive hardware elements are installed, including the bond strap  130  and bolt plates  140 / 146 , as well as how the bolt strap tabs  134  are inserted into both corner slots  84  and wall end unit slots  122 . As will be appreciated, the male wing portion of the wall unit that abuts corner unit  20  must be shaved down slightly so as to make that portion substantially coplanar with the upper surface of projection  78 , and thereby to accommodate a split corner plate half  134  installed at the end of the perpendicular bond straps  130 . 
     In some applications, the first course may need to be set in mortar. When this is necessary, the highest point in the curb is identified and the mortar is laid slightly higher. A dry line is used to establish alignment and to make certain the units are level from front to back. Dry stacking is continued up to four courses at each end tapering down toward the center. 
     Once alignment of the first course is confirmed, added courses are removed at each end. End tie straps or triangular corner ties (preferably sixteen gauge galvanized) are installed with the tabs bent up or down as needed for insertion into a slot in the end or corner block. The recessed slot is then preferably filled with masonry adhesive, which is typically provided in tubes which can be applied in small controlled amounts, squeezed from a hand held gun. The adhesive is not used to glue the courses together but to fill the void in the recessed slot and to lock the unit&#39;s position relative to the sheet metal tab once the adhesive is cured. Two more courses are then stacked at each end or corner as before and the required ties are installed. 
     Installation of the triangular corner plate ( FIGS. 7C-7D ) or the alternative corner plate design ( FIG. 7H ) requires the top of the adjacent wall unit be cut for a recess. This is the only location where any units need to be cut and it is done for the sole purpose of creating a physical tie between the first anchor bolt in each direction of the wall. 
     Second Course to Bond Strap: When ready to install a second course, first the vertical alignment of the units is checked in each direction and at each end with a hand level. Once this is confirmed, a mason&#39;s block is used to hold the dry line and re-establish the line from end to end or corner to corner at the top edge of the second course. The second course is laid while checking alignment along the length of the wall. A hand level is used to check level from front to back as needed. Wall alignment with the dry line is checked to ensure that front-to-back level is satisfactory. The third course is laid after raising the dry line to the top edge of the third course. 
     Shimming is employed only as required to maintain alignment with the dry line or to maintain plumb. If a mortar bed was required for the first course, it may be best to allow the mortar to set over night. Dropping in a select few bolt plates and hand threading nuts over the anchor bolts will secure the low wall overnight. Three eight inch high courses bring the wall to bond strap height if 24 inch anchor bolts are employed, while three inch high brick units may have several courses to go before the bond strap would bolt the assembly down. 
     Bond Strap to Bond Strap: As noted previously, generic engineering can provide bond strap intervals at prescribed heights for given wall applications and conditions. This is true also for any change or reduction in the bolting pattern requirements. 
     Bolting the wall at each prescribed bond tie accomplishes three important functions. First, it applies the greatest structural strength where it is most needed—namely, the lower portion of the wall. Secondly, the hardware secures the wall in its proper position while under construction. And thirdly, it obviates the need for bolting higher in the wall. Site specific conditions or special engineering may require the lower courses to be fully grouted for seismic codes or greater structural integrity. This can be achieved by pouring grout into the voids prior to installing bond straps. 
     After setting over night, if needed, the vertical plumb of each end or corner in each direction is checked. The dry line is reestablished and the wall alignment checked end to end. Units are leveled front to back using shims only as needed. 
     The next course is built up at each end as before and end and corner ties are installed and embedded in masonry adhesive. The dry line is raised to the next course and the next course is then laid. Alignment is again checked. This sequence is repeated until the course level is within one course of the first bond strap. The end of anchor bolts must be at least one inch above the top of the next course. The correction of one or more anchor bolts may be achieved with a coupling nut, such as the Simpson CNW⅝. If a more radical correction is necessary, lowering the bond strap by one course is always possible. 
     At bond strap height, bolt plates are dropped in over the anchor bolts using the holes punched in the bolt plates. Bolt plates fit into the recess on the back edges of the male wing elements on the units. The bond straps can be provided in any length, though standard 113″ lengths are preferable. As described above, each end is slotted to create and provide tabs that can be bent up and down to fit into the recessed slots of the block units. Starting at one end, the bond strap is laid into the recess at the top of wall and end units. The hole pattern provided matches the bolt pattern and locks in the alignment of units front to back. The bond strap when placed rests atop the bolt plates. Alignment of the wall is regularly checked against the dry line as additional straps are laid down the length of the wall. Each bond strap should overlay the previous strap by at least one anchor bolt. 
     At the opposite end the bond strap may be cut to length with a slot added to allow for bent tabs. With the bond straps laid in place from end to end, hole alignment is checked and confirmed for the threaded holes in the bolt plate (if the threaded hole embodiment is used) in relation to the holes in the bond strap. Each end is also checked for vertical alignment or plumb. Wall alignment with the dry line and also checked and nuts are threaded onto all anchor bolts when ready. Nuts are tightened to a predetermined torque setting, and threaded extension rods are installed in the threaded hole at the specified spacing using properly secured bolt plates. Wall end vertical alignment and alignment down the length of the wall are rechecked and stacking of the next course is started. 
     Since end units alternate with the recessed top to the bottom to mate with the ends of wall units, it is possible that the final block is set top down, which prevents the bond strap from connecting to the end of the course. In such a case, the end anchor bolt can be secured at the lower course with bolt plate and end tie strap, then torque tightened to a specified setting. A threaded extension rod is then added at this level and the same condition will be repeated at the next bond strap. This will secure the end of the wall. A similar situation may arise at a corner, and a similar solution is provided. However, corners do not require bolt plates but use coupler nuts and may require the anchor bolt or extension rod to be cut to the correct length. 
     Cap Course: Once the number of courses is laid to bring the wall to its designed height and the last bond strap is in place, the top course is set with the top down. This constitutes the cap course, and it is secured, sealed, and protected from the elements by filling the anchor bolt cell with grout. The end units may have the slotted recess filled with masonry adhesive to secure them to the bent tabs of the bond strap as well, but once the grout has cured it will lock the ends and corners into position. If desired, several flat wall caps can be added to provide a decorative finish. These caps can be secured with masonry adhesive in a manner well known in the art. 
     Square Columns: Referring next to  FIGS. 7E-7F , it will be seen that by using the intact square corner plate of  FIGS. 7A-7B , a square free standing column can be erected. This assembly requires four corner units  20  assembled in a square and joined by an undivided corner plate  160  with the corners slotted  172  for bent tabs. The anchor bolt  200  is located and secured at the center of the column. The tabs on the bolt plate are bent up and down in the same fashion as wall corners, inserted into slots  84  in the corner units, and installed with masonry adhesive to fill the voids left after inserting the tabs into the slots. Again, the adhesive is only provided as a means to permanently lock the unit position, not to glue it down. Additional structural integrity may be gained by fully grouting the interior cell prior to bolting the assembly to the specified torque setting. 
     The above disclosure is sufficient to enable one of ordinary skill in the art to practice the invention, and provides the best mode of practicing the invention presently contemplated by the inventor. While there is provided herein a full and complete disclosure of the preferred embodiments of this invention, it is not desired to limit the invention to the exact construction, dimensional relationships, and operation shown and described. Various modifications, alternative constructions, changes and equivalents will readily occur to those skilled in the art and may be employed, as suitable, without departing from the true spirit and scope of the invention. Such changes might involve alternative materials, components, structural arrangements, sizes, shapes, forms, functions, operational features or the like. 
     Therefore, the above description and illustrations should not be construed as limiting the scope of the invention, which is defined by the appended claims.