US3768225A

US3768225A - Method of precasting a masonry wall panel

Info

Publication number: US3768225A
Application number: US00264740A
Authority: US
Inventors: M Sloan
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-04-03
Filing date: 1972-06-21
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30

Abstract

A method of precasting a masonry wall panel having a pair of spaced wythes of masonry units bonded together by a concrete core, with each wythe having metal rod reinforcing lattices partially embedded in mortar between the masonry wall units and projecting into the concrete core. The method includes first precasting each of the wythes by arranging masonry units in a bed and applying mortar between the masonry units with metal rod reinforcing lattices positioned in the mortar in projecting disposition, and then positioning these precast wythes in spaced face-to-face relation with concrete therebetween to form the core that bonds the wythes together and embeds the projecting lattices in the core.

Description

nited States Patentv [1 1 Sloan METHOD OF PRECASTING A MASONRY 'WALL PANEL [76] Inventor: Mangum W. Sloan, 2836 Sunset Dr., Charlotte, NC. 28209 [22] Filed: June 21, 1972 [21] Appl. No.: 264,740

Related 0.8. Application Data [60] Continuation of Ser. No. 70,431, Sept. 8, 1970,

abandoned, which is a division of Ser. No. 718,405,

' April 3, 1968, Pat. No. 3,530,632.

[52] US. Cl. 52/743, 52/425' [51] Int. Cl. E04c 2/06 [58] Field of Search 52/741, 743,434, 52/425, 426, 431; 264/253, 255

References'Cited UNITED STATES PATENTS 2,688,175 9/1954 Billner ..264/263 3,321,884 5/1967 Klaue ..52/426 FOREIGN PATENTS OR APPLICATIONS 823,501 12/1951 Germany 52 434' 51 Oct. 30, 1973 Switzerland 52/424 Switzerland 52/431 Primary Examiner-Price C. Faw, Jr. Attorney-Channing L. Richards Ma].

[57] ABSTRACT A method of precasting a masonry wall panel having a pair -of spaced wythes of masonry units bonded together by a concrete core, with each wythe having metal rod reinforcing lattices partially embedded in mortar between the masonry wall units and projecting into the concrete core. The method includes first prec'asting eachof the wythes by arranging masonry units in a bed and applying mortar between the masonry units with metal rod reinforcing lattices positioned in l the mortar in projecting disposition, and then 'position ing these precast wythes in spaced face-to-face relation with concrete therebetween to form the core that bonds the wythes together and embeds the projecting lattices in the core 13 Claims, 7 Drawing Figures unner!!! PAIENIEDnm 30 ms SHEET 10F 4 i u R MANGUM W. SLOAN BY Maui b SW11 AT R g--ii .vifissssss w TO NEYS mmmmo um i 3,768,225

INVENTOR MANGUM w. SLO AN ATTORN EYS PATENTED EST 3 0 I973 SHEET 3 [1F 4 INVENTOR MANGUM W. SLOAN ATTORNEY! PATENTED UN 3 0 I975 SHEET t 0F 4 XNVENTOR MANGUM w SLOAN Rifle-dun z, Slwtlo ATTORNEY METHOD OF PRECASTING A MASONRY WALL PANEL C ROSS-REFERENCES TO RELATED APPLICATIONS This is a continuation of parent application Ser. No. 70,431, filed Sept. 8, I970, now abandoned, and which was a division of application Ser. No. 718,405, filed Apr. 3, 1968, now US. Pat. No. 3,530,632, issued Sept. 29, 1970.

BACKGROUND OF THE INVENTION The present invention relates toprecasting of masonry wall panels. Presently, prefabricated wall panels are generally known and used, primarily for the purpose of expediting construction and minimizing costs in comparison with on-the-job construction. The time and labor savings advantage of prefabricated wall panelsis especially significant in masonry construction as inconvenient, inefficient, and expensive on-the-job brick or block laying is eliminated. A single wythe precast masonry wall panel can be simply preformed to serve as a non-load bearing veneer, facing or partition panel, but cannot normally serve as a load bearing member, especially when formed from standard brick units. Therefore, the problem has been to obtain a precast masonry wall panel of sufficient strength to serve as a load-bearing member and ofa simple construction that can be efficiently and inexpensively preformed.

Various attempts have been made to provide precast masonry wall panels, but without wholly satisfactory results. For example, French Patent No. 545,541, dated July 25, 1922, discloses casting of masonry units in a wythe with reinforcing lattices bonded in mortar between the units. In one embodiment the lattices are disposed wholly within the surfaces of the wythe, without any projection for attachment to or embedding in any structural material or for structural combination with a second wythe. In a second embodiment both the lattices and the mortar project close tothe level of additional components, but again the lattices are wholly embedded in the mortar and do not provide a lattice projection for attaching to or embedding in any structural material or for structural combination with another wythe. In a third embodiment, similar to the second, some of the masonryunits are of greater thickness than others and the lattices and mortar project close to the level of the thicker units with the lattices wholly embedded in the mortar without projection for attaching to or embedding in any structural material or for structural combination with another wythe.

SUMMARY OF THE INVENTION By the present invention, a precast wall panel is provided with reinforcing means that is partially embedded in mortar in a masonry unit wythe and projects for attachment to a structural material as by securement in a concrete structural layer, which is preferably a core to which another similar wythe is similarly secured, or is secured directly to reinforcing means projecting from an opposed spaced wythe. Thus, the precast panel is provided with sufficient reinforcement for use of the panel as a load-bearing structural component, rather than as only a non-load-bearing veneer, facing or partition member. Further, the reinforcement is so disposed in the panel that the construction can be varied to suit particular structural and design requirements. Imporrods,

tantly, this reinforced masonry wall panel is precast in a simple and inexpensive manner that provides a complete precast panel requiring no on-the-job construction other than that necessary for securement in the building structure, which is accomplished simply due to features of the method of the present invention.

Basically, the method of the present invention provides a masonry wall panel having a single wythe of masonry units, such as brick, bonded together by mortar with reinforcing means partially embedded in the mortar between the units and projecting from one face of the wythe. This reinforcing means provides the strength for load-bearing use of the panel and the projection of the reinforcing means provides means for attachment of the wythe to a building structure or to other componentsof the panel. A layer of concrete may be bonded to the face of the wythe with the projection of the reinforcing means embedded therein for further strengthening of the panel and to provide a concreteface on one side of the panel.

Preferably, a pair of such masonry wythes with projecting reinforcing means are combined in spaced relation to form a double wythe panel with a concrete core bonding the wythes together into a composite panel with the reinforcing means projections embedded in the core, or the wythes can be secured together without a core by welding together the reinforcing means projecting from the opposed wythes.

For simplified attachment in a buidling structure, metal attaching plates are secured to the ends of the concrete layer or core adjacent the side edges of the panel for attachment by welding to corresponding plates of adjacent panels and to metal components of the buidling structure.

In the preferred embodiments the reinforcing means is a vertically extending metal rod lattice having a pair of spaced rods, one embedded in the mortar between the masonry units and the other spaced from the face of the wythe and with an intermediate metal rod extending sinuously between and secured to the spaced As further reinforcement, grid means may be embedded in the concrete core between spaced wythes with the spacing of the wythes-being sufficient to space the projecting-reinforcing means to accommodate the grid means therebetween.

- The masonry wall panel is preformed according to the methodof the present invention by arranging a plurality of masonry units, such as brick,in a single layer bed, and positioning reinforcing means between the units with a portion of the reinforcing means projecting 1 above the bed while allowing mortar to set between the units to bond the units together and to embed the rein- .forcing means partially in the mortar. The reinforcing lowed to set in the space between wythes to form a core bonding the wythes together and embedding the reinforcing means projections in the core. For further reinforcement, the wythes may be spaced sufficiently to provide a space between the oppositely projecting reinforcing means andreinforcement grid means may be disposed in this space. i

Alternatively, a double wythe panel can be precast omitting the concrete core by spacing the wythes so that the reinforcing means projecting from one wythe abuts the reinforcing means projecting from the other wythe, and then welding the abutting reinforcing means projections together to form an integraldouble wythe panel. 7

The aforementioned attaching plates may be included in precasting the single wythe, concrete layer embodiment or the double wythe, concrete core embodiment by positioning the plates prior to setting of BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, partially broken away, of a masonry wall structure built with precast masonry wall panels made according to a preferred embodiment of the method of the present invention;

FIG. 2 is a side elevation, partially broken away, of

the wall structure of FIG. 1;

FIG. 3 is an enlarged plan view of abutting portions of two adjacent wall panels, showing the joint therebetween, of the wall structure of FIG. 1 and as viewed along line 3-3 of FIG. 2;

FIG. 4 is an enlarged fragmentary perspective view of a portion of a wall panel as viewed along line 4-4 of FIG. 1;

FIG. 5 is an enlarged perspective view of a reinforced single wythe in the position in which it is cast prior to forming with a corresponding wythe into a wall panel as shown in FIG. 4;

FIG. 6 is an enlarged fragmentary view similar to FIG. '4 and illustrating a modification of the wall panel of FIGQ4; and

FIG. 7 is an enlarged fragmentary view similar to FIGS. 4 and 6 and illustrating a single'wythe wall panel structural load-bearing building component. In the emt'i'ces 20 extend substantially the full height of the

wythes

12 and 14 and are disposed between the first and second and between the third and fourth vertical rows of brick in a four row wythe construction.

The

wythes

12 and 14 of each panel are coextensively positioned in spaced face-to-face relation with the lattices projecting into the space between wythes, which space is filled with a concrete core 28 that bonds the wythes l2 and 14 together and embeds the inwardly spaced rods 24 of the lattices 20 therein.

. Thethickness of the concrete-core 28 is sufficient to provide a space between the lattices 20 projecting from opposite wythes for convenient disposition of vertically arranged reinforcement grid means 30in the space between lattices 20. The grid means 30, as illustrated in FIG. 4, is simply a system of conventional reinforcing rods and can be omitted where not required to provide strengthening.

The concrete core 28 substantially completely fills the space between the

opposed wythes

12 and 14, though voids maybe provided if desired to reduce the weight and cost of the panel 10 and the composition of the concrete may vary to obtain desired properties. The range of variations in the concrete composition and in I the volume of voids, if any, is determined primarily by of another preferred embodiment of the present inven- 7 DESCRIPTION OF THE PREFERRED EMBODIMENTS In the preferred embodiment of the present invention illustrated in FIGS. 1-4, the precast masonry wall panel l0 is a double wythe construction. The

wythes

12 and 14 are each formed from conventional building bricks arranged in vertical rows with mortar 18 conventionally disposed between the brick 16 and forming a bond therebetween. The

wythes

12 and 14 may be of any de sirable height and length suitable for use in a particular building structure. For example, the height may be 'equivalent to the spacing between the foundation and 'cient strength in the panel for use of the panel as a the particular strength, moisture resistance, thermal insulation, and acoustical insulation properties desired for a specific use. In this regard, special coating layers may be applied to the inner faces of the wythes and different core compositions used'in different areas of the panel to obtain special characteristics.

In the embodiment illustrated, the concrete core 28 also serves as a support for attachment of the precast panel 10 in a building structure, and for this purpose the core fills the space between

wythes

12 and 14 at the four corners of the panel for securement thereat of metal attaching plates that consist of a pair of upper attaching plates 32 secured to the upper end of the core 28 adjacent the opposite side edges of the panel 10 and disposed between and substantially flush with the upper surfaces of the

wythes

12 and 14, and a pair of lower attaching plates 34 secured to the lower end of the core 28 adjacent the opposite side edges of the panel 10 and extending across the lower surfaces of both

wythes

12 and 14 to the outer faces thereof.

S'ecurement of the attaching

plates

32 and 34 to the core 28 is enhanced by anchoring members in the form of metal rods 38 welded to the plates and extending into the core with an inner hook'configuration that prevents dislodgment of the plates from the core.

The location of the upper attaching. plates 32 adjacent the side edges of the panels 10 results in abutment of each upper attaching plate 32 of one panel with a corresponding upper attaching plate 32 of the adjacent panel so that the abutting plates can be welded together, as indicated at 36, in FIGS. 1 and 3, to secure the panels together in a multi-panel wall structure. At corners of the wall structure the upper attaching plate 32' of one panelextends beyond the side edge of its panel for abutment with the corresponding plate 32 of the other corner panel.

The lower attaching plates 34 serve to attach the panels to the building foundation by welding, as seen at 40 in FIGS. 1 and 2, to metal anchoring plates 42 located directly under the lower attaching plates 34 on.a foundation footing 44 on which the panels 10 are supported.

A wall structure is built, using the described precast wall panels 10 of this preferred embodiment of the presentinverition by laying the foundation footing 44 to extend continuously. under the wall structure at a width greater than that of the wall panels 10. Anchor bolts 46 are embedded in the footing outwardly of both sides, of the intended panel locations and at spacings along the footing 44 equivalent to the length of individual panels. These anchor bolts 46 extend above the surface of the footing 44 for extension through the anchoring plates 42,'which are'thereby bolted to the footing at locations aligned with the intended locations of the lower attaching plates 3.4 of the panels. These anchoring plates 42 extend widthwise sufficiently for bolt attachment and extend lengthwise sufficiently for disposition under the lower attaching plates 34 of adjacent panels 10.

A panel 10 is then placed on the footing 44 with a mortar joint 48 between the footing and panel and extending intermediate the anchoring plates 42, and the lower attaching plates 34 are welded alongtheir exterior edges to the anchoring plates 42. Additional panels. are then sequentially erected in a similar manner with adjacent panels secured together by a vertical mortar joint 50 and by welding of the abutting upperattaching plates 32. A roof system 52 may then be erected ontop of the panels "10. l I

The resulting precast panel wall structure requires no further structural support, and due to the reinforcement incorporated in the individual panels it has sufficient strength in itself to serve as a load-bearing wall structure. As a matter of fact, for some purposes suffi-' cient strength is obtained with reinforcing lattices incorporated in only one of the two wythes.

As mentioned heretofore, the concrete core 28 provides desirable properties. However, there may be instances wherethjese properties are not necessary or where the properties of a void between the

wythes

12 and 14 are desired, in which case the modification of FIG. 6 is suitable. This coreless precast wall panel 54 is a double wythe

construction having wythes

56 and 58 and reinforcing lattices 60

identical tothe wythes

12 and 14 and reinforcing lattices 20 of the panel 10 of FIGS. 14, but with the

wythes

56 and 58 disposed so that the inner rods 64 of the lattices on one 'wythe 56 abut the inner rods 64 of the lattices of the other wythe 58 with the abuttingrods 64 and 64 welded together, as shown, along their abutment. As there is no core to which attaching plates may be secured, this coreless precast wall panel is secured in a building structure by mortar or other conventional means. I

The precast

masonry wall panels

10 and 54 of the embodiments of FIGS. l-4 and FIG; 5 have brick at both faces. which is'desirable in many applications for aesthetic and physical property purposes. There are applications, however, where brick on one of the faces is not desired or is not necessary. For these applications the precast masonry wall panel of the present invention can be modified accordingly as shown in FIG. 7. This modified panel 66 is a single wythe construction having a wythe 68 with reinforcing lattices 70 identical to the wythes l2 and 14 and lattices 20 of the panel 10 of FIGS. 14, and having a concrete layer 72 similar to the concrete core 28 of the embodiment of FIGS. 1-4 and providing a concrete surface on one face of the panel 66. This concrete layer 72 is bonded to the brick on the face of the wythe 68 from which the lattices 70 project and is preferably, though'not necessarily, of a thickness sufficient to embed completely therein the projecting portions of the lattices 70. The concrete layer 72 also can serve the same purpose as the concrete core 28 of the embodiment of FIGS. 1-4 for 'securement thereto of upper and lower pairs of attaching plates identical to the

plates

32 and 34 of the embodiment of FIGS. 1-4.

Further, where the properties of a concrete layer are not necessary, the single wythe 68 with reinforcing lattices 70 can serve as a single wythe precast masonry wall panel without a concrete layer. Such a panel can be secured in a building structure by mortar or'by mortar and welding of the metal lattices to'metal components of the building structure.

All of the described embodiments of the precast masonry wall panel are simply and. inexpensively preformed by the method of the presnet invention, wherein the reinforced wythes are first precast individually and then further processed to form one of the illustrated panel embodiments, or used without processing as a simplified panel.

These reinforced individual wythes are preformed as illustrated in FIG. 5 by arranging a plurality of brick 16 in a single layer flat bed 74 with the bed 74 having the dimensions of the desired finished wythe and with the brick arranged in spaced relation in rows corresponding to the vertical rows of spaced relation in rows corresponding to'the vertical rows of the completed wythe. In the embodiment illustrated, the brick are arranged in four rows.

The reinforcing lattices 20 are then placed in the sp'acingsbetween the first and second and between the second and third rows of brick with the one rod 22 of each lattice20 well within the space between brick and the other rod 24 parallel to and above the brick. Mortar.

18 is then poured in fluid form into all of the spaces between brick, which results in the rods 22 being embedded in the mortar. While the lattices 20 are retained in position, the mortar is allowed to set, thereby bonding the brick together and bonding the lattices in the mortar with portions projecting above the brick.

The initial positioning of the lattices 20 may be accomplished either before or after pouring of the mortar,'but in either case they should be retained in position until the mortar has set sufficiently to support the lattices.

wythes l2 and 14 formed as described above are disposed in spaced face-to-face relation with the lattice s projecting into the space therebetween and with the reinforcement grid means 30, if used, positioned between wythes and between the lattices projecting from opposite wythes. The concrete can be applied by pouring onto a flat wythe and then positioning the other wythe on top of the concrete. Preferably, however, the two wythes are first arranged in erect face-to-face dispostion and the concrete poured into the space therebetween. Upon setting, the concrete forms the aforementioned core 28, bonding the wythes together by interface bonding with the brick and-by having embeddedtherein the projections of the lattices 20.

The aforementioned attaching

plates

32 and 34 are placed in position either before or after pouring of the concrete, but in either case before the concrete sets.

A modification of this embodiment can be formed by omitting the lattices 20 in the precasting of one of the wythes and otherwise proceeding as described above.

To complete the preforming of the wall panel 54 of the embodiment of FIG. 6, a pair of reinforced

wythes

56 and 58 formed asdescribed above'are disposed in spaced face-to-face relation with the projecting rods 64 of the lattices 60 of opposed wythes abutting, and then welding the rods 64 together to form the integral panel 54.

To complete the preforming of the wall panel 66 of the embodiment of FIG. 7, a single reinforced wythe 68 formed as described above is covered on the face from which the lattice projects with concrete poured in fluid form thereon in a thickness sufficient to cover the projections of the lattices 70. Upon setting, the concrete forms the aforementioned layer 72 that is bonded to the brick and has the lattices 70 embedded therein. Attaching plates identical to the

plates

32 and 34 of the embodiment of FIGS. 1-4 may be placed for securement in this concrete layer 72 in the same manner as the

plates

32 and 34 are positioned for securement in the concrete core 28 as described above.

The thickness of the concrete layer 72 of the embodiment of FIG. 7 is preferably sufficient to completely embed the projecting lattices 70 therein, although in some cases it may be desirable to limit the thickness so that the lattices 70 project therebeyond to provide convenient means for attaching the panel to a building structure.

From the above it is apparent that the method of precasting a masonry wall panel of the present invention is adaptable to numerous variations and it is to be understood that other variations and modifications are within the scope of the present invention, which is not intended to be limited to the foregoing detailed description or otherwise, except as defined. in the appended claims.

I claim:

1. A method of precasting a masonry wall panel, said method comprising placing a plurality of masonry units in an arrangement forming a single layer bed, placing reinforcing means between said masonry units with a portion of said reinforcing means projecting thereabove, bonding said reinforcing means and said units together by pouring mortar between said masonry units and allowing it to set with said reinforcing means only partially embedded in said mortar.

2. A method of precasting a masonry wall panel according to claim 1 and characterized further in that said placing said reinforcing means is performed before emortar is poured between said units, and said pouring of mortar is performed while said reinforcing means remains so placed.

3. A method of precasting a masonry wall panel according to claim 1 and characterized further in that said pouring of mortar is performed prior to said placing of said reinforcing means.

4. A method of precasting a masonry wall panel according to claim 1 and characterized further by subsequently bonding said reinforcing means in a concrete layer by pouring a layer of concrete on said bed of masonry units with said projecting portions of said reinforcing means in said concrete layer and allowing said concrete layer to set.

5. A method of precasting a masonry wall panel according to claim 4 and characterized further in that said reinforcing means is a metal rod lattice having a pair of spaced rods connected by a sinuously extending rod and said placing of said reinforcing means is performed to dispose one of said spaced rods between said masonry units and the other of said spaced rods above said units.

6. A method of precasting a masonry wall panel according to claim 4 and characterized further by bonding attaching plates to said concrete layer adjacent the side edges of at least one end of said bed.

7. A method of precasting a masonry wall panel, said method comprising, precasting a pair of coextensive wythes of masonry units having said masonry units to each wythe bonded together by mortar between units and with at least one wythe having reinforcing means bonded by said mortar to said units and projecting from one face of said at least one wythe, placing said wythes in spaced face-to-face relation with said reinforcing means projecting into the space between wythes, and bonding said wythes together and said reinforcing means in the space between wythes by pouring concrete in the space between wythes and allowing the concrete to set and form a concrete core in which the projecting portion of said reinforcing means is embedded.

8. A method of precasting a masonry wall panel according to claim 7 and characterized further in that subsequent to precasting of said wythes one of said wythes is positioned horizontally, and said bonding is performed by pouring said concrete on the upper face of said one wythe prior to said placing of the wythes in spaced face-to-face relation and then placing the other of said wythes in face-to-face relation above said one wythe and in contact with said concrete prior to setting thereof and with said reinforcing means projecting into said concrete.

9. A method of precasting a masonry wall panel according to claim 7 and characterized further in that in said placing of said wythes they are placed in an erect position and said concrete is poured into the space between wythes.

10. A method of precasting a masonry wall panel according to claim 7 and characterized further in that both said wythes are precast with reinforcing means,

and said wythes are placed in spaced face-to-face relation with said reinforcing means projecting from both said wythes into the space therebetween.

11. A method of precasting a masonry wall panel according to claim 7 and characterized further in that both wythes are precast with reinforcing means, in that 10 said method comprising separately precasting a pair of coextensive wythes of masonry units having said masonry units of each wythe bonded together by mortar between units and with metal rod lattices bonded by said mortar to said units and projecting therefrom, placing said wythes in spaced face-to-face relation with said projecting lattices of one wythe abutting the projecting lattices of the other wythe, and bonding said abutting lattices together by welding to form an integral double wythe wall panel.

@2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,768,225 Dated October 30, 1973 Inventor) Mangum W. Sloan It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2, line 29, "buidling" should read --building; line 34, "buidling" should read --building--. Col. 3, line 64, "emough" should read --enough-. Col. 6, line28, "presnet" should read -present-;

line 38, delete "to the vertical rows of spaced relation in rows corre-"; line 39, delete "sponding". Col. 8, line 2, "emortar" should read -mortar-. Col. 9, line 4, "reinformcement" should read r-reinforcement.

Signed and sealed this 16th day of April 197A.

(SEAL) Attest:

EDWARD 1-IJ*'L :.'TCHER,JR. C. I IARSHALL DANN Attesting Officer 1 Commissioner of Patents

Claims

2. A method of precasting a masonry wall panel according to claim 1 and characterized further in that said placing said reinforcing means is performed before mortar is poured between said units, and said pouring of mortar is performed while said reinforcing means remains so placed.

7. A method of precasting a masonry wall panel, said method comprising precasting a pair of coextensive wythes of masonry units having said masonry units to each wythe bonded together by mortar between units and with at least one wythe having reinforcing means bonded by said mortar to said units and projecting from one face of said at least one wythe, placing said wythes in spaced face-to-face relation with said reinforcing means projecting into the space between wythes, and bonding said wythes together and said reinforcing means in the space between wythes by pouring concrete in the space between wythes and allowing the concrete to set and form a concrete core in which the projecting portion of said reinforcing means is embedded.

10. A method of precasting a masonry wall panel according to claim 7 and characterized further in that both said wythes are precast with reinforcing means, and said wythes are placed in spaced face-to-face relation with said reinforcing means projecting from both said wythes into the space therebetween.

11. A Method of precasting a masonry wall panel according to claim 7 and characterized further in that both wythes are precast with reinforcing means, in that in said placing of said wythes they are placed at a spacing sufficient to provide a space between the portions of the reinforcing means projecting from opposite wythes, and by placing reinforcement grid means in the space between said reinforcing means projecting portions prior to setting of said concrete core.

12. A method of precasting a masonry wall panel according to claim 7 and characterized further by bonding attaching plates to said concrete core adjacent the side edges of at least one end thereof.

13. A method of precasting a masonry wall panel, said method comprising separately precasting a pair of coextensive wythes of masonry units having said masonry units of each wythe bonded together by mortar between units and with metal rod lattices bonded by said mortar to said units and projecting therefrom, placing said wythes in spaced face-to-face relation with said projecting lattices of one wythe abutting the projecting lattices of the other wythe, and bonding said abutting lattices together by welding to form an integral double wythe wall panel.