US3064392A

US3064392A - Concrete roof and wall structure

Info

Publication number: US3064392A
Application number: US381589A
Authority: US
Inventors: Arthur C Avril
Original assignee: A&T Development Corp
Current assignee: A&T Development Corp
Priority date: 1953-09-22
Filing date: 1953-09-22
Publication date: 1962-11-20
Anticipated expiration: 1979-11-20

Description

Nov. 20, 1962 A. c. AVRIL 3,064,392

' CONCRETE ROOF AND WALL STRUCTURE Filed Sept. 22, 1953 GSheets-Sheet 1 IN V EN TOR.

' ATTORNEYS.

Nov. 20, 1962 A. c. AVRIL CONCRETE ROOF AND WALL STRUCTURE 6 Sheets-Sheet 2 Filed Sept. 22, 1955 ATToeA/gs.

Nov. 20, 1962 A. c. AVRIL CONCRETE ROOF AND WALL STRUCTURE 6 Sheets-Sheet 3 Filed Sept. 22, 1953 ATTORNEYS Nov. 20, 1962 A. c. AVRIL 3,064,392

CONCRETE ROOF AND WAL L STRUCTURE Filed Sept. 22, "1953 6 Sheets-Sheet 4 e0 J g/ Mfi. BY

ATTORNEYS 1962 A. c. AVRIL 3,064,392

CONCRETE ROOF AND WALL STRUCTURE Filed Sept. 22, 1953 GSheets-Sheet 5 um um mm s. 8N I! O3 m mm mm w m mmJ I i J on & .4 mw vm m m rm m h Mk M. BY m zwn 5 5 mm Ndv. 20, 1962 A. c. AVRIL CONCRETE ROOF AND WALL STRUCTURE 6 Sheets-Sheet 6 Filed Sept. 22, 1955 Ll Q INVENTOR BY 105ml, i

ATTORNEYS 3,064,392 CONCRETE RGQF AND WALL STRUCTURE Arthur C. Avrii, Wyoming, {)hio, assignor to A and T Development Qorporation, St. Bernard, Shin, a corporation of ()hio Filed Sept. 22, 1953, Ser. No. 381,589 2 (Ilaims. (Cl. 59-147) This invention relates to the construction of concrete buildings and is directed in particular to a concrete roof structure for erection upon the walls of such buildings. The invention involves both method and apparatus aspects, both relating to the construction of a monolithic roof slab and the construction of a ceiling which is spaced downwardly relative to the roof slab for heat insulating purposes.

The present application is a continuation in part of the copending application of Arthur C. Avril entitled Methd and Apparatus For Erecting Concrete Structures, Serial No. 85,748 which was filed on April 6, 1949 now abandoned.

The method of the copending application involves the erection of concrete building walls by pouring successive horizontal courses of wet concrete without the use of conventional wooden forms. For this purpose, precast concrete columns are erected in perpendicular position upon a footing and in spaced relationship to one another. The vertical columns delineate the plane and thickness of the wall and serve as guides for horizontal courses of narrow metal forms which are clamped against opposite sides of the adjacent columns. In this position, the forms provide shallow troughs extending lengthwise between the columns. Upon the installation of each set of forms, wet concrete is poured and tarnped into the trough which they provide and the procedure of erecting additional form courses one upon another and of pouring and tamping the concrete is repeated until the desired wall height is obtained. This method produces a monolithic wall with the precast beams embedded in the wall and also provides a simple inexpensive procedure completely eliminating the construction of wooden forms.

The metal forms which are utilized in practicing the above method are the subject matter of another copending application of Arthur C. Avril entitled Sectional Concrete Forms, Serial No. 277,830, filed on March 21, 1952, now Patent No. 2,762,105 and the forms disclosed therein are also utilized in erecting the roof slab of the present application.

One of the primary objects of the present invention has been to provide a monolithic roof slab involving the use of precast concrete beams which are arranged to perform the double function of supporting a series of forms in a predetermined plane for pouring the slab, and of providing rigid means for anchoring the spaced ceiling structure after the forms are removed from the hardened slab.

By virtue of the precast beams, the forms are erected in a rapid inexpensive manner without the use of conventional forms, since the beams themselves provide the supporting and guiding means for the forms. After pouring the slab, the beams are partially embedded in it to provide strength; moreover, the lower edge portions of the beams project downwardly from the slab and provide irregular surfaces to which the ceiling structure is directly keyed for support.

In erecting the slab, the precast beams, which are generally of I-beam shape in cross section, are placed across the walls of the building spanning the walls at a spacing related to the length of the metal forms, such that the forms may be placed transversely between adjacent beams and supported by the beams. Accordingly, the beams delineate the plane of the roof and simplify the erection procedure since the usual expensive form Work is elimi- Patented Nov. 20, 1962 nated completely. Otherwise expressed, the beams themselves form an essential part of the form work; however it is a rather simple matter to adjust them individually to a common plane to form the roof skeleton. Thereafter the forms are placed on them in a routine manner and the slab is poured to a predetermined depth across the forms with the marginal portion of the slab resting upon the top of the walls. This bonds the slab both to the beams and to the walls to provide a monolithic concrete structure.

In order to support the forms, pairs of rails, preferably of wood, are placed against the web of each beam on opposite sides, with the rails resting upon the lower flange of the beam and clamped temporarily by C-clamps against the opposite sides of the web. The rails project outwardly on opposite sides beyond the edges of the flanges and provide supporting surfaces for the opposite ends of the forms which are placed crosswise between adjacent roof beams. The forms are slightly shorter than the spacing between the lower flanges of adjacent beams; consequently, upon removal of the C-clamps and rails, the forms may be dropped from between the beams.

The upper surfaces of the rails collectively are disposed in a plane to locate the forms below the upper flanges of the beams such that the flanges above the forms are embedded in the roof slab. After the concrete slab has been poured and allowed to set, the C-clamps and rails are readily detached from the beams, allowing the forms to be dropped downwardly from the slab surface.

As noted above, the upper flanges of the roof beams are embedded in the slab, leaving their lower flanged portions projecting downwardly below it. The ceiling is anchored upon a framework preferably of wood, which derives support directly from the lower flanges of the roof beams. For this purpose,'the ceiling structure includes wooden stringers extending transversely between adjacent beams with their opposite ends configurated to key into the sides of the roof beams above the lower flanges, thus anchoring the stringers firmly to the beams. Vertical studs are attached to the wooden stringers, the studs having upper ends engaged against the surface of the roof slab; thus the stringers are held rigidly by the beams and slab against deflection in the vertical plane. Thereafter, furring strips, which extend at right angles to the stringers, are attached to the lower end portions of the studs which project downwardly below the stringers. The furring strips thus secure the stringers rigidly in their transverse relationship to the beams and also provide means for attaching the ceiling which may be either of lath and plaster or of dry wall construction.

From the foregoing, it will be observed that in addition to reinforcing the roof slab, the roof beams, which are easily set and adjusted to delineate the roof plane or planes, are utilized both for supporting and guiding the forms and for providing a direct anchorage for the ceiling structure. By taking advantage of the I-beam cross section of the beam arrangement therefore, the roof and ceiling is improved structurally and the construction costs are reduced.

A further object of the invention has been to provide means for directly attaching a spaced wall panel to the concrete walls to provide a dead air space extending downwardly from the ceiling. During erection of the walls, sheet metal form ties are utilized to space and attach the wall forms relative to one another. These spacers are left embedded in the concrete wall and, after removal of the forms, provide limbs which project from the inner surface of the wall. The projecting limbs, which are ductile, are utilized to attach wood furring strips to the inner surface of the wall, the limbs being clinched over upon the strips to clamp the strips firmly against the concrete wall. Thereafter, metal lath may be nailed directly to the furring strips for application of a plastered wall or wall board panels or plywood may be attached in the usual manner.

Various other features and advantages of the invention will be more fully apparent to those skilled in the art from the following description, taken in conjunction with the drawings.

In the drawings:

FIGURE 1 is a top plan view of a building, showing the roof beams for a hat roof installed and the forms and reinforcing rods in position at one portion of the building ready for pouring the slab.

FIGURE 2 is a view similar to FIGURE 1, showing the concrete roof slab partially poured, with the remaining forms set in position.

FIGURE 3 is a sectional view taken on line 3-3 FIG- URE 2 illustrating a part of the roof slab and temporary supporting structure for the forms.

FIGURE 4 is a sectional view taken on line 44 FIG- URE 3, illustratnig particularly the attachment of the temporary rails to the roof beams and supporting the ends of the forms.

FIGURE 5 is a plan view of one of the end panels of the wall forms which are utilized in pouring the roof.

FIGURE 6 is an end view of the form panel illustrated in FIGURE 5.

FIGURE 7 is a perspective view illustrating the flat roof of FIGURES l and 2 at completion.

FIGURE 8 is a sectional view showing the roof beams erected to provide a pitched roof.

FIGURE 9 is an enlarged view similar to FIGURE 8, showing the forms installed and the slab partially poured.

FIGURE 10 is a sectional View taken on line 1010 FIGURE 9, detailing the mounting of the forms similar to FIGURE 4.

FIGURE 11 is a sectional view similar to FIGURE 10, showing the completed roof slab with'the forms removed, illustrating the attachment of the ceiling framework to the precast beams.

FIGURE 12 is a sectional view taken on line 1212 FIGURE 11, further detailing the ceiling structure.

FIGURE 13 is a sectional view taken on line 1313 FIGURE 12, further illustrating the ceiling structure;

FIGURE 14 is a plan view illustrating one of the form ties which are utilized in clamping the wall forms to the columns during erection of the walls and which are later utilized in clinching the furring strips for the wall lath or panel as illustrated in FIGURE 12.

The fiat roof structure illustrated in FIGURES 1 to 4 and 7 is similar to that disclosed in the copending application and the pitched roof of FIGURESS to 13 follows the same principles of construction. In both forms, the roof slab comprises a reinforced concrete structure which is erected by initially locating across the top of the building walls, series of precast concrete roof beams or purlins spaced from one another and spanning the walls. Thereafter, the sheet metal forms are mounted transversely between adjoining roof beams in side-by-side relationship, with their opposite ends supported by the beams as explained in detail later. Reinforcing rods are then placed upon the collective forms, the wet concrete is poured, levelled and allowed to set; thereafter the forms are removed from beneath the slab.

, The sheet metal forms impress into the lower surface of the roof slab a geometric arrangement of ribs extending transversely between the roof beams and imparting a finished architectural ceiling pattern. Depending upon the utility and architectural design of the building, this pattern may be left exposed, or on the other hand, a plastered or dry wall ceiling may be installed in spaced relationship to the surface pattern to provide a dead air space for heat insulation. 7

It will be understood at this point, that the roof slab and its precast concrete beams form a monolithic concrete structure bonded to the wallsand possessing a high degree of mechanical strength and that the structure is essentially the same whether the roof is flat or of the pitched variety.

As disclosed in the drawings, the present roof structure is constructed upon concrete building walls erected by the method disclosed in the copending application. According to the prior application, precast vertical columns are first installed and the walls are erected by pouring courses of wet concrete successively one upon another, utilizing sectional forms which are clamped in pairs against the opposite sides of vertical precast columns. The columns are erected at spaced points according to the plan of the building and in true vertical positions; thus they serve as guides during the erection of the forms so as to eliminate expensive wooden form work and simplify the erection procedure. As the wet concrete is poured into the courses of forms and tamped, the successive courses bond firmly to one another and to the columns and embed the columns in the wall as an integral part of it.

When the full height of the complete building wall is obtained, sockets are formed in the upper portions of op posed walls to receive the opposite ends of the precast roof beams. The beams span the walls and are adjusted to a common horizontal plane in the case of a flat roof or they are adjusted to the desired angle in the case of a pitched roof; thereafter, the form panels are installed lengthwise between the roof beams. To simplify the setting of the forms, the roof beams are located upon centers suitable to receive between them the elongated forms (FIGURE 5) which were previously used in constructing the wall. It will be understood that placing the beams accurately upon the walls determines the plane of the roof slab in advance and after the beams are accurately located, the forms may be set rapidly by unskilled workmen and without utilizing complex wooden form structures.

Briefly, the present structure and method of erection takes advantage of the I-beam cross section of the beams to provide the following significant improvement over conventional building practices:

In the first place, the prelocated roof beams simplify the erection of the concrete forms since the forms are readily set in position transversely spanning adjacent beams and supported by wood rails temporarily clamped,

on opposite sides of the beams, as shown in FIGURES 3 and 4. The beams themselves thus directly receive and support the forms and weight load of the concrete roof slab without intricate form construction.

Secondly, after the roof slab is set and the forms removed from it, the roof beams are utilized to support the ceiling frame, again taking advantage of their I-beam cross section, as shown in FIGURES 11 and 12. For this purpose, a series of ceiling joists or stringers, preferably of wood, are wedged between adjacent roof beams,-

the opposite ends of the joists being shaped to mate with the I-beam cross section such that the joists are keyed rigidly to the beams. The ceiling proper is supported by a suitable wood frame attached to the joists as explained later in detail.

Referring to FIGURE 2, which illustrates in plan view the erected walls 15 of the building and the erection of the forms thereon for a flat roof structure, it will be observed that the precast roof beams 16 are located in sockets 17 formed in the upper portion of the walls on oppdsite sides. The concrete beams art somewhat thicker than the vertical columns previously noted and'the sockets have sufiicient depth to locate the upper edges of the beams flush with the top of the wall. The beams are spaced apart to receive between them the forms 18, with the end portions of the forms located downwardly of the flanges 20 of the beams as indiciated in FIGURE 4.

As disclosed in the copending application, the forms used in the wall construction are of a length adapted to the present day modular construction system and are extensible lengthwise. They are made up of three sections, consisting of an intermediate section and a pair of end sections telescopically related. The individual sections preferably have a length corresponding to the eight foot lineal unit or multiple thereof used in locating I-beams and columns, such that the sections fit between them. In the present disclosure, the end form sections are utilized in pouring the concrete roof and the precast roof rafters are placed at eight foot centers adapting the form sections to fit endwisely between the beams.

As best shown in FIGURE 4, the ends of the first row of forms 18 extend from the inside surface of the wall and their ends adjacent the wall are supported by a horizontal wood beam 21, which rests upon vertical shoring members 22. The opposite ends of the first and succeeding courses of forms are supported by rails 23* 23, for example, wood two by fours, which seat against opposite sides of the web 24 of the roof beam 16, with their lower edges resting against the lower flange 25 of the beam on opposite sides. The two by fours are clamped against the opposite sides of the web by C-clamps 26 which are spaced from one another along the beam as shown in FIGURE 3. The wood rails 23 extend outwardly beyond the side edges of the flange 25 to support the ends of the flanges; thus, upon removal of the rails, the forms can be dropped down from between the adjacent roof beams without difficulty.

As best shown in FIGURE 3, the walls of the building are provided with vertical reinforcing rods 27 which project upwardly beyond the top of the wall. After the forms are mounted, the extended ends 28 of the reinforcing rod are bent over upon the forms, such that upon pouring the edges of the roof slab are tied to the walls. In addition, longitudinal and transverse reinforcing rods 39 and 31 (FIGURE 1) are installed upon the forms to strengthen the roof slab. These rods have their ends extended to the walls around the periphery of the building with their ends interposed between the extended ends 23 of the wall reinforcing rods.

It will be observed in FIGURES 3 and 4, that the wet concrete roof slab is bonded to the upper portion of the concrete roof beams and to the upper edges of the walls so as to provide a monolithic concrete roof and wall structure.

To prevent sagging of the relatively flexible sheet metal forms under the weight load of the wet concerte, the forms derive supplemental intermediate support from the temporary scaffolding indicated generally at 32 in FIG- URES 3 and 4. The scaffolding may be a commercial product, for example, tubular framework having vertical adjustment means (not shown) so as to brace the forms at points in a common plane. The scaffold structure rests upon the floor slab of the building and includes vertical columns 33 suitably braced as at 34. The columns have at their upper ends respective horizontal cross members 35 attached to the vertical columns and reinforced by the bracing members 34. The forms are engaged by respective wood beams 36 resting upon the cross members 35 and extending at right angles across the lower edges of the forms. The beam 36 engages the intermediate portions of the forms as shown in FIGURE 4 and maintains all of the forms in a common horizontal plane to prevent any tendency to spring or sag when the wet concrete is poured into them.

It will be understood that the roof beams and their wood rails 23 provide the primary support for the forms and also, by locating them accurately in a common plane relative to one another, delineate the plane or planes of the roof slab. The scaffolding provides added support for the forms and the wet concrete slab. Moreover, being vertically adjustable, the scaffolding promotes safety and convenience in removing the forms since it may be lowered just enough to drop the forms from the hardened slab for convenient removal.

As best shown in FIGURES 1, 2 and 3, a rail 37 preferably formed of wood, forms a curbing or closure to retain the wet concrete which is poured to a level above the plane of the forms and above the top of the building Wall. The rail 37 extends around the periphery of the building as indicated in FIGURE 1 and forms a permanent part of the roof structure. The rails 37 are held in place temporarily by wires 38, each having an end anchored upon the end extensions of the form ties 46 which are left projecting from the wall after the wall forms are removed as explained later. The wires extend over the side and top of the rail 37 and are attached as at 41 to the bent ends 28 of the wall reinforcing the rods. Rail 37 is anchored permanently to the roof slab by studs or lag screws 42 (FIGURE 4) passing into the rail and having an outer end portion embedded in the roof slab.

After the forms are installed and braced by the scaffolding, and the reinforcing

rods

30 and 31 properly positioned and wired together, the wet concrete is poured into the forms as indicated at 43 in FIGURES 2 and 3. The wet concrete is distributed uniformly and, by means of levelling boards, is worked level and flush with the curb rails 37 in a manner well known in the building trade. After the slab has set thoroughly, the scaffolding 32 is adjusted downwardly a sufiicient distance to allow the forms to be dropped from the slab. The C-clamps are then loosened and the rails 2323 removed so that the forms can 'be released and dropped upon the top of the scafiolding. Thereafter, the forms can be removed in a safe and convenient manner from the scaffolding.

The form contour provides a ribbed ceiling having a finished architectural surface with the upper portions of the roof beams bonded in the slab and the lower portions of the beams projecting downwardly below the plane of the slab to serve as support means for the ceiling structure as explained in detail later. The exposed slab may be utilized in this condition as the ceiling if desired, or the downwardly spaced plastered or dry wall ceiling may be installed beneath the slab for heat insulation.

Referring to FIGURES l1 and 12, the spaced ceiling, indicated generally at 44, is shown installed on a pitched roof building, however it will be understood that the identical construction is applied to the flat roof shown in FIGURES 3 and 4. The ceiling is supported by a framework, preferably of wood, indicated generally at 45 which derives its support directly from concrete roof beams in a manner generally similar to the forms previously described. As shown in FIGURE 11, the ceiling frame structure is supported by a series of ceiling joists or stringers 46 which extend transversely between the spaced beams, with the opposite ends of the stringers wedged between adjacent beams and rigidly supported by the lower fiange 25 thereof.

For this purpose, the opposite ends of the stringers are cut to interfit the l-beam cross section of the beams, the upper portion of each stringer having a projecting tongue 46a which overlies the flange 25 and abuts the web 24 of the beam. The stringers are installed by placing them in a generally diagonal position between adjacent beams, then forcing them to right angular relationship, whereby the stringers are firmly wedged between the beams. The stringers are then rigidly fixed in a common plane by attaching to the sides of the stringers a series of vertical studs 47, the studs having upper ends which seat upon the lower surface of the concrete slab; therefore, the stringers and their associated parts are locked securely against deflection in a common plane. The ends of the stringers which abut the walls of the building have their ends configurated to nest between the ribs of the Walls, which have a surface pattern corresponding to the lower surface of the roof slab.

Attached to the lower ends of the vertical studs is a series of furring strips 48 which extend parallel to the roof beams and transverse to the stringers. The furring strips thus tie the stringers securely relative to one another in right angular wedging engagement with the roof means and also support the ceiling itself. In the construction shown in FIGURES l1 to 13, metal lath 50 is attached to the furring strips in the usual manner and the metal lath is plastered as at 51. In dry wall construction, the lath and plaster is omitted and instead, conventional plasterboards or plywood panels (not shown) are attached directly to the furring strips in place of the lath and plaster.

It will be understood that the several parts of the wood framework 45 are preferably nailed together, the stringers first being wedged in between the concrete beams and walls and the vertical studs and furring strips thereafter nailed to them. This structure provides a rigid support for the downwardly spaced ceiling and provides an ample dead air space beneath the roof slab for thermal insulation.

It will be apparent from the foregoing disclosure, that the roof beams reinforce the roof slab and are also utilized for the purpose of supporting and guiding the forms in a common plane and for providing a rigid support for the spaced ceiling structure. In their function as form supports, the prelocated beams allow the forms to be set in a simple manner by unskilled workmen. In their function as anchorage means for the ceiling structure, the beams collectively provide a simple mode of attaching the spaced ceiling structure to the concrete ceiling slab.

According to the pitched roof structure shown in FIG- URE 8, the roof beams 16 are joined at center by bolts '52 passing through metal clamping plates 5353 which areseated against the webs of the beams on opposite sides. The lower ends of the beams are joined by means of bolts 54 to respective cross beams 55 which are seated in sockets 17 formed in the top portion of the Walls as described earlier. The cross beams span the building Walls and, by their connection to the lower ends of the roof beams, provide a self-sustaining truss suitable to resist the lateral forces developed by the weight load of the roof.

'If a fiat ceiling is desired, it may be attached to the cross beams 55, otherwise the ceiling structure is tied to the pitched beams as described earlier. Asindicated by the broken lines a in FIGURE 9, the building may a simple manner by unskilled workmen. In their funccross beams 55 are omitted and the upper ends of the roof beams rest directly upon the bearing Wall.

The forms are installed between the pitched roof beams as shown in FIGURES 9 and 10 in identically the same manner as the flat roof installation' It will be noted that the ends of the forms are supported by rails 23-23 and C-clamps 26, and that the forms are braced intermediately' by the scaflolded sections 32. In this instance the scaflolds are adjusted to several elevations to accommodate the wood beams 36 which are located at several planes corresponding to the incline of the roof beams.

It will be observed in FIGURE 9, that the collective forms extending across the inclined roof beams present a series of troughs 56 extending horizontally along the inclined roof skeleton. The troughs form the ribs 57 in the ceiling and are effective to key the wet concrete slab to the inclined form surface. roof has a steep pitch, the troughs aidin overcoming the tendency of the wet concrete to slide down the inclined form surface.

Referring to FIGURES 5 and 6; each form 18 comprises a panel 58 including marginal flanges 60 bent at right angles to the plane of the form. The flanges provide stiffness and also provide interfaces between adjoining forms. The central portion 61 of panel 58 is depressed with respect to theplane of the form on the side opposite the flanges (FIGURE 6) to further stiffen the form. This panel impresses the depressed panel 62 in the surface of the ceiling (FIGURE 12). The flat marginal portions 63-63 intermediate the flanges and depressed panel collectively impress the ribs 57 in the ceiling surface. In addition, the opposite end portions of the form include flat end panels 6L -64 which provide the ribs 65 In the event that the adjoining the roof beam on opposite sides (FIGURE ll). The ribs 57 provide maximum strength while keeping the dead weight as low as possible; The ribs alongside the roof beams extend at right angles to the ribs 57 and thus strengthen the slab along the axes of the beams.

As best shown in FIGURE 12 the interior wall surface is molded by the same forms as are utilized in pour ing the roof slab, therefore the'interior surface of the wallshave a geometric pattern impression matching ceiling surface. In erecting the walls, the form ties 40 are placed crosswise of the inner and outer forms and are utilized to clamp the forms in spaced relationship against the vertical columns. As indicated in FIGURE 14, the outer ends of the form ties 46 are split to provide a pair of limbs, 6767 which are clinchedrespectively in opposite directions upon the opposite sides of the form flanges as described in the copending application. After the wall hardens, the limbs are straightened out for removal of the forms, the ties being embedded in the concrete wall. broken off flush with the outside surface of the Wall.

In the event that it is desirable to take advantage of the ribbed profile of the wall to form a dead air space for heat insulation similar to the ceiling structure, the

limbs of the form ties are utilized to mount the furring' strips for the wall panel structure. As shown in FIGURE 12, pairs of furring strips '68, preferably of wood, are attached horizontally to the concrete wall surface, with the furring strips located above and below the protruding limbs. The strips are attached by' clinching one of the limbs upwardly over the opposite strip as indicated at 70 and by clinching the other limb downwardly over the lower strip as indicated at 71. The respective pairs of strips are thus attached rigidly at spaced intervals to the Wall surface for attachment of metal plaster lath or wall panels. As shown in FIGURE 12, plaster lath indicated at 72 is nailed directly to the strips in the conventional fashion and thereafter a coating of wall plaster is applied. By virtue of the furring strips and cavities in the wall surface, a series of dead air cells, indicated at 73, is formed between the concrete and plaster walls.

From the foregoing, it will be noted that the forms:

are supported in side-by-side relationship upon the roof beams without'being tied together, thus simplifying the.

setting operation. By virtue of the longitudinal flanges of the forms, interfaces are provided between them such that all parts of the slab are in direct contact with the metal form surfaces to impress a finished architectural surface texture to the slab.

The ribbed pattern of the slab surface providesmaximum strength both along the axes of the beams and transversely to them and thereby reduces the weight load of the slab while providing adequate strength. This allowsthe beams to be set a great deal further apart than in conventional structures, the beams of the present disclosure being located at eight foot centers as dictated by the length of the forms.

Having described my invention I claim:

1. A concrete roof slab and ceiling structure for installation upon the walls of a building comprising, a plurality of precast concrete roof beams each havingintegral upper and lower flanges joined by a vertical web,

said integral lower flanges projecting along opposite sides 7 of said .web, said roof beams laterally spanning spaced support members of the building and disposed in spaced parallelism relative to one another, a concrete roof slab having marginal edges overlying the building support members, the slab extending across said roof beams with the upper flanges of the roof beams embedded therein and providing a monolithic structure, the web and lower flanges of the roof beams projecting downwardly to a common plane spaced from the lower surface of the concrete slab, a plurality of stringers extending transversely be- V tween adjacent roof beams and disposed in spaced paral lelism relative to one another, the stringers having a length The protruding ends of the limbs are then' corresponding to the spacing of the adjacent roof beams, the opposite ends of said stringers having a configuration mating with the webs and lower flanges of adjacent roof beams and keying the stringers between adjacent roof beams, a series of vertical studs attached to the stringers, the studs having upper ends engaged against the lower surface of the concrete slab and locking the stringers downwardly against the lower flanges of the roof beams, said studs having lower ends projecting downwardly below the stringers, a plurality of furring strips extending transversely across said stringers and attached to the lower ends of the vertical studs, said furring strips locking the stringers transversely in keyed position between the roof beams, and a ceiling panel attached to the lower surface of said furring strips and disposed in spaced relationship to the roof slab.

2. A concrete roof slab and ceiling structure for installation upon the walls of a concrete building comprising, a plurality of precast concrete roof beams each having an irregular surface profile along opposite sides coextensive longitudinally therewith, said roof beams extending across the walls of the building and disposed in spaced parallelism relative to one another, a concrete roof slab having marginal edges overlying the building walls and bonded thereto, the slab extending across said roof beams, the lower surface of the roof slab having respective longitudinal ribs projecting downwardly therefrom, said longitudinal ribs overlying said roof beams and co-extensive therewith, the upper edge portions of the roof beams embedded in said longitudinal ribs and providing a monolithic structure, the lower portions of each roof beam projecting downwardly to a common plane spaced from the lower surface of the concrete slab, a plurality of stringers extending transversely between adjacent roof beams and disposed in spaced parallelism relative to one another, the stringers having a length corresponding to the spacing of the adjacent roof beams, the opposite ends of each of said stringers having a configuration mating with the irregular surface profiles of adjacent roof beams and keying the stringers between adjacent beams, a series of vertical studs attached to the stringers, the studs having upper ends engaged against the lower surface of the concrete slab and locking the stringers downwardly with respect to the roof beams, said studs having lower ends projecting downwardly below the stringers, a plurality of furring strips extending transversely across said stringers and attached to the lower ends of the vertical studs, said furring strips locking the stringers transversely in keyed position between the roof beams, and a ceiling panel attached to the lower surface of said furring strips and disposed in spaced relationship to the roof slab.

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