US2083725A - Preformed slab building structure - Google Patents

Description

June 15, 1937;

F. 5. MANSKE AL PREFORMED SLAB BUILDING STRUCTURE Filed Feb. 26, 1932 F950 AMA lvs KE INVENTOR Patented June 15, 1937 .UNlTED STATES PREFORMED SLAB BUILDING STRUCTURE Fred A. Manske, Chicago, and Roy V. Yeager, Eyanston, Ill., assignors to United States Gypsum Company, Chicago, Ill., a corporation of Illinois Application February 26, 1932, Serial No. 595,348 17 Claims. (CI. 72-68) The present invention pertains to building structures or the like. and more particularly relates tostructures in which interlocking, preformed slabs are supported by spaced supporting members, as in a floor or roof construction,

and to novel components of such a structure.

There are numerous prior art structures concerned with pre-fo-rmed slabs and their erection in floors, roofs and walls. Most of these struc-' of the need in the building trades, and the ini 20 dustries supplying them, of an efficient, relatively inexpensive and simple, ready-formed building material adapted for construction of fireproof floors and roofs, which can be completely made up at the factory and transported 25 in an efficient, compact manner requiring a minimum of space, and which maybe erected by relatively inexperienced workmen on-standard supporting structures without regard to special spacings of such supports. The present inven- 30 tion, we feel, provides features never heretofore successfully applied in this art.

An object of this invention, therefore, is to provide a floor or. roof construction which is made of pre-formed slabs intimately locked to- 35 gether and securely fastened to standard supports.

Another object of the invention is to provide a cementitious slab of simple, novel construction for use in building structures.

40 Another object of the invention is to provide an exceptionally long span gypsum tile equally reinforced against bending and compression stresses and, adapted for cantilever suspension without failure.

p 45 An additional object of the invention is t'o.

provide a simple clip adapted to secure preformed slabs in building structures, and 'constituting an element of the structural combi-' Reference is to be had to the accompanying drawing forming a part of this specification, in

which:

Figure 1 is a fragmentary, perspective view of a; floor or roof structure embodying features of the invention;

Figure 2 is a cross sectional view of one of our new precast building slabs;

Figure 3 is a perspective View of a right hand clip which we have devised for securing the slabs to building supports;

Figure 4 is an edge view of a left hand clip;

Figure 5 is a fragmentary, sectional plan view illustrating the relationship of adjoining slabs, clips and supports:

Figure 6 is'a perspective view of a modified form of clip; and

' Figure 7 is a perspective view of an additional modification. I

Our erected construction preferably comprises supports l0, pre-formed slabs H and securing clips I2. The slabs H are preferably reinforced, precast, rectangular tile formed of a cementitious material, such as calcined gypsum, but may be of any other suitable cementitious material or combination of materials, such as hydraulic cement, clay or the like. The supports III are preferably bar joists, but any other suitable type of beam or jo-istmay be used.

In the preferred form, the slabs H are provided with tongues on certain sides and complementary grooves or recesses on opposite sides so that a surface such as a floor or roof comprised of these slabs is locked into a monolithic structure capable of uniformly sustaining any stresses to which such a surface is ordinarily subjected. As shown, tongues l3 are formed on the longitudinal sides of the slab intermediate plane surfaces l5 and [5a of the same, and tongues M are formed on the end sides. These tongues are beveled so that they are thicker at their bases or where they begin to protrude from the sides of the slab than at their extremities. The tongues M are preferably spaced somewhat from the corners of the slab to simplify the casting operation as well as to minimize the possibility of destruction during handling prior to erection. The opposite sides of the slab are provided with complementary grooves l6 and I1. While it has been found preferable to provide the slabs H withthe end tongues l4 and grooves Il, these may be omitted, if desired, and only the tongues I3 and grooves I6 may then be formed on the slabs. Projections l8 and I9, coincident with the'faces l5 and I5a, respectively, between less liable to deformation by breakage or chip-v ping in handling. Another advantage of this beveling lies in the fact that should there be any irregularities or slight deformities either on the tongues or in the grooves which will tend to aggravate the use of force to occasion the proper closeness of fit between adjacent slabs there will be little danger of the projections I8 and I9 being forced to spread and break off, the

irregularities being compensated for by compression of the material itself.

In order to further strengthen the slabs, a mat reinforcement 2| of suitable metallic-mesh, such as a fabrication of wire or metal lath, is preferably embedded throughout the slabs. This reinforcing mat 2I is preferably doubled over so that the edges thereof will extend into the projections I8 and I9 and the apex 22 projects into the tongue I3, while the intermediate portions of the mat lie adjacent to the faces l5 and I5a, the slabs thus being thoroughly reinforced at all positions which will be called on to support substantial loads or resist stresses imposed on the floor or roof construction, for which the slabs are particularly adapted. While the mat 2| is preferably of one piece, with the body portion thereof preferably spaced apart and embedded adjacent the faces I5 and I5a of the slab, this arrangement having been found very successful in actual practice, this reinforcing may, of course, comprise a plurality of reinforcing elements. A tile reinforced as described is capable, of sustaining strains and complex bending moments equally at any portions upon either face and permits of uses heretofore impracticable with building tile made of such relatively frangible materials as gypsum and other plastic cementitious products.

In the slabs or tiles heretofore known, there has always been present the danger resultant upon failure if the slabs were not employed in such a combination that the stresses imposed by loads fell in a certain way. For instance, practically all such known slabs were provided with reinforcement through their center or adjacent the lowermost face, as the slabs were generally I intended to span between only a pair of supports with the ends supported by these supports. Naturally, in such a structure the bending stresses would all be concentrated in the lowermost surface or face of the slab. The cost of. such 'a structure would obviously run rather high because of the many slabs required for every unit of floor or roof and/or the heavy structure required for the purpose, and the assembly of such a structure would be rendered relatively cumbersome. If one of those slabs were to be subjected bearing surface up to a cantilever or fulcrum suspension and loads imposed on either or both ends, there would be failure with a fraction of the load necessary to cause failure were such slab suspended the spacing demanded by the use to which the.

floor or roof is to be put or the loads which it will be called upon to sustain. As illustrated in Fig. 1,

load is imposed upon this suspended end there will be a bending moment upwardly at the nearest point at which the slab rests upon a support; and this bending moment is increased as loads are imposed between said point of support and the opposite end of the slab. Moreover, when a load is imposed as last mentioned there will be a downward bending moment imposed on the slab by such load. Due to the reinforcement throughout adjacent both faces of the slab, however, the strains and counter-strains to which the slab is subjected are prevented from causing failure of the slab at any point within the limits of the combined tensile strengths of the cementitious material and the reinforcement employed. This feature also permits the use of the slabs regardless of which face is uppermost.

In order to secure the slabs to the supports Ill, we have devised the novel clip I2, which, in the preferred embodiment, comprises a shank 25 and a slab engaging portion 26. These clips are preferably stamped from thin gauge sheet material, such as galvanized iron or the like. The shank 25 preferably comprises a lateral slot 21, having a lip-like lug 28 formed integral with its lower edge, this lug being bent at an angle out of the plane of the shank. The slot 21 is adapted to engage a flange 30 of support II], the lug 28 pressing up against the under side of the flange 3|] so that this flange will be frictionally gripped between the upper edge of the slot and the lug to prevent the clip from slipping out of engagement. This frictional engagement is effected by merely bending the lug 28 sufficiently out of the plane of the shank 25 to allow for theengagement of the flange 30, while holding the clip at an angle to the flange, and, after the flange 30 has been embraced, pulling the clip up to substantially right angular relationship with the flange, whereby the lug 28 exerts a resilient force against the flange. Inasmuch as the shank 25 has been somewhat weakened against bending stresses by the cutting of the slot 21, an elongated bead or crimp 3| is preferably impressed therein intermediate the slot and the edge of the shank opposite the slot. This bead is preferably formed to intersect a line coincident with the edge of the slot on which the lug 28 is formed, so as to rlgidify the shank against the bending stresses set up when the lug 28 is forced against the flange 30, as heretofore described.

The slab engaging portion 26 of the clip is pref erably so formed as to engage the. tongues I3, and to this end it is bent into a channel-like or substantially U-shaped form, having a web 33, a leg 34 forming the connection with the shank 25, and a leg 35, the whole being of such shape as to engage the tongue of the slab in a substantially snug fashion. In order to provide secure engagement with the sides of a slab, and where the slab is of such a substantially penetrable material as gypsum, a prong 36 is preferably formed integral with the engaging portion 26 of the clip. As shown in Figs. 3 and 4, this prong 36 is formed in the web 33 and is adapted to be forced into tongue I3 of the slab (Fig. 5). A prong 3'! may, however, be formed on the edge of the leg 35 (see Fig. 6) whereby to penetrate the slab above the tongue I3. A salient advantage of this prong feature resides in securing the clip against displacement from engagement with the side of the slab due to the tension produced by the lugs 28 after the clips have been placed in position, and

prior to the placing of another slab in abutment therewith. Where for any reason it is desired to dispense with the prongs, as where the material of the slabs will not permit of penetration or other conditions do not render a prong desirable, this feature may be dispensed with (see Fig. 7) The slab engaging portion 26 may, of course, be modified as desired to conform to whatever style of tongue and recess arrangement that may be found advantageous. I

It will be obvious that, when in place, slabs II will be out of contact, along their adjacent sides, a distance equal to the thickness of the clips 12. It has, therefore, been found desirable to provide abutment pads 38 on the sides of thetongues l3, and abutment pads 39 on the sides of the grooves i6. These pads are preferably formed only adjacent to the corners of the slabs, and are preferably only of a thickness substantially equal to the thickness of the clips after the clipsare in place. With these pads it has been found that should the clips be placed irregularly there will be no tendency of the slabs to skew and thus cause irregularities in the surface arrangement of the structure. In addition there will be a more thorough contactual relationship between adjoining slabs. Although for purposes of illustration the proportionate thickness of the pads 38 and 38, and the dimensional proportions of 'the clips in the reduced views, are somewhat exaggerated,

. it is to be understood that no dimensional limitations are to be construed from the illustrations.

We have found that very desirable results are obtained with a clip of sheet metal of about 18- to 20 gauge. It is, therefore, apparent that in practice the space between abutting slabs where the clips are interposed is not of very great consequence. Nevertheless, we have found it desirable, where it is desired to have a close fitting surface, to provide a tapered nosing 40 along one edge of the slab coincident with a face thereof, and extending beyond the side on which it is formed, a distance substantially equal to the space formed by the interposed clip l2 and the contact or spacer lugs 38 and 39. Obviously, this nosing 40 could he formed on either of the projections I8 or l9 or either of the shoulders of the tongued side of the slab; and this nosing may be formed by extending the entire projection or shoulder without tapering. However, to facilitate manufacture, the form of nosing best illustrated in Fig. 2 has been found preferable. With this form of nosing a line contact is formed with adjacent slabs.

In erecting a floor or roof, the supports or purlins, which are preferably flanged, and which may be of any desirable type, are placed, say, with spacing up to 30 and 36 incheson center. The

slabs, formed as heretofore described, are set in place on the supports in staggered, interlocking relationship. In order to effectuate staggering of the slabs, half length slabs may be provided as starters at the edges of the building, or full length slabs may be cut in half on the job. A salient advantage of our constructionresides in the interlocked staggered relationship of the slabs since it permits of considerable variation in joist or purlin spacing because the slabs may be placed without regard to joint spacing, as it is not necessary to have supports for the abutting ends since the tongue and groove joints on the sides of the two slabs.

forcement throughout the slabs renders them peculiarly adapted to sustain the loads to which the structure will be subjected.

The clips I2 are not an indispensable element of the structure, but are preferably employed to tie down the floor or roof to the supports, thereby locking the same against lifting forces such.

alternate opposite sides of the shank 25 are provided so that they are adapted to engage alternate opposite sides of flanges 30 of the supports. The clip shown in Fig. 3 maybe termed a right hand clip and those shown in Figs. 4, 6, and '7 left hand" clips, as considered from the viewpoint of the man placing them in erection. This finds particular utility in structures where light joists are employed which may, under the stress of loads, tend to warp somewhat. With the clips alternated throughout the structure it is obvious that the supports are securely locked in place against the slabs and will be substantially prevented from warping. The clips are thus a unifying element performing a double function,not only locking the slabs to the supports but also locking the supports to the slabs. The prongs 36 or- 31 find particular utility during erection in overcoming the force of the lug 28, which tends to draw the clips back out of contact with the slab, until another slab is brought in engagement against that side. In addition, of course, these prongs serve to prevent accidental displacement of the clips after they are in place.

Due to the staggered relationship of the slabs, the pads 38 and 39 (as in the embodiment illustrated in Fig. 1) will engage adjacent the center of each abutting tile, whereby to provide, in addition to the indirect engagement of the slabs through the clips, twice as many direct contacts through the lugs as there are lugs on each slab. Thus there is no undue strain upon any one portion of either the projections between which the grooves are formed or the tongues, when, loads are placed on the surface formed by the slabs.

The floor or roof herein contemplated may be provided with any desired covering such as mastic cement, roofing, tile, terrazzo, wooden flooring, linoleum, or the like. These coverings may be placed directly upon the slab surface, or this surface may first be waterproofed in any desired manner. Where wooden flooring is to be placed over the floor, and the slabs are of such relatively penetrable material as gypsum, sleepers may be nailed directly to the. slabs. applied directly to a floor of the present construction by cementing it down directly upon the close surface formed by the slabs. In this connection the nosing 4B. which is adapted to bridge eventually show as depressed lines upon the finished linoleum surface. This nosin'g is also of advantage where it is found desirableto. allow the clip-formed separation between adjoining tile as a grout space, and the nosing is so placed as to make contact along the lower edge, where Linoleum may be i 10 wood lumber. A load bearing slab practical to manufacture and capable of use in the simple manner and for all the purposes described, we believe, has never before our invention been placed on the market. It is to be understood,

15 of course, that we do not limit ourselves to any particular dimensions or materials, as other block sizes, made of any suitable materials, may be found of equal efliciency. The method of reinforcing, hereinbefore described, which we have 20 found most desirable, makes the slabs peculiarly adaptable for use with either face upward while yet retaining all the benefits of unity of structural strength. Our construction provides an economical floor or roof structure, of a minimum of parts, in mill units adapted for great flexibility of construction; and the slabs may be severed, as by sawing, on the job to any desired sizes as particular conditions necessitate.

We would state in conclusion, that while the illustrated examples constitute practical embodiments of our invention, we do not wish to limit ourselves precisely to these details, since manifestly, the same may be considerably varied without departing from the spirit of the invention as defined in the appended claims.

, Having thus described our invention, we claim as new and desire to secure by Letters Patent:

1. In a floor or roof construction, a plurality of supports, an elongated, pre-formed, cementitious slab spanning said supports, said slab being reinforced substantially throughout its extent adjacent each face to substantially equally withstand bending moments on either face, and said slab being sustained by said supports only at points intermediate its ends, at least one of said ends being suspended in substantially cantilever fashion.

2. In a floor or roof construction, spaced supports, reinforced, precast, cementitious slabs spanning said supports, tongues formed along.

two sides of said slabs, said slabs having correposite said tongues in which the tongues of adjacent slabs are adapted toengage, and reinforcgrooves interlocking said blocks to form a monolithic structure, clips engaging'the purlins and gripping said tongues to secure said blocks ag st lifting forces, and said clips engaging substa ially alternate'opposite edges of the supports whereby any tendency of the supports to shift sidewise is prevented.

4. In a building construction, a. plurality of spaced supports, pre-formed slabs arranged in staggered relation adjacent said supports, means for securing said slabs to said supports, the sides of said slabs having interlocking tongues and grooves, integral spacing pads formed on said tongues and in said grooves and limiting the ap-.

'proach of said slabs one to the other along said sides, said pads being formed adjacent the corners of said slabs and engaging adjoining slabs only adjacent their center, whereby each slab is in direct engagement with adjoining slabs at twice as many points along its sides as there'are.

pads on said sides. I

5. In a floor or roof construction, pre-formed slabs forming the substantial surface of said construction, adjacent slabs being slightly spaced apart throughout the major portion of the depth of their adjacent sides to accommodate the positioning of securing clips therebetween, but contacting with each other adjacent a face only with a line contact.

6. A precast rectangular slab having integral tongues formed on two adjacent sides thereof and having complementary grooves formed on the other twosides thereof, one of said tongues extending along the entire length of the side and the other of said tongues terminating a substantial distance inwardly from each end of the corresponding slab side.

7. A precast slab comprising a substantially flat, rectangular body portion, a tongue formed along a side of said slab, and integral pads at intervals along said tongue, said pads providing the only points of substantial engagement with adjoining slabs.

8. A pre-formed slab,the sides of said slab having tongues and grooves adapted to engage with complementary tongues and grooves of adjoining slabs, integral pads formed on a tongue and providing the only substantial contacting surface with an adjoining slab, and a projection coincident with the outer face of said slab formed along the side having the tongue with pads, said projection bridging the gap between adjoining slabs formed by said pads.

9. A long span, reinforced, pre-cast gypsum building tile having a tongue extending along one edge of the same and having spaced equivalent reinforcing means throughout adjacent all direct load bearing surfaces and extending into said tongue, said reinforcement rendering said tile resistant to bending moments in any direction.

10. In a floor or like construction, a plurality of supports, precast slabs resting on and spanning the supports, interlocking tongues and recesses formed on the sides of said slabs, and metallic clips engaging said tongues and said supports to lock said slabs against said supports.

11. In a building structure, spaced supports, precastcementitious slabs spanning said supports, tongues formed along the edges of said slabs, other slab edges having grooves formed therein for engagement with said tongues to lock said slabs in a monolithic structure, integral pads formed on the sides of said tongues and in said grooves and engaging the sides of the complementary grooves and tongues of abutting slabs, said pads spacing said slabs one from the other, and clips engaging said tongues and within said grooves in the spaceformed between abutting slabs by said pads and locking said slabs to said supports.

12. In a building structure, spaced supports, precast cementitious slabs spanning said supports, said slabs having interlocking tongues and recesses formed along the edges whereby to lock said slabs into a monolithic structure, integral pads formed on the sides of saidtongues and engaging the sides of complementary recesses of adjoining slabs, said pads spacing said slabs one from the other, and a projection formed along the edge of a slab coincident with the upper face thereof, said projection bridging the space formed between adjoining slabs by said pads and being adapted to engage the edge of said adjoining slab, whereby a uniformly close appearing upper surface is formed in said structure.

13. In a precast, cementitious slab adapted for floor or like construction, a tongue formed on one side of said slab, the opposite side of said slab having a recess formed therein adapted to receive a tongue of an adjoining slab, and metallic mesh reinforcement embedded within said slab in two substantially coextensive layers spaced substantially apart on each side of .the center plane of said slab and extending into'said tongue.

14. A long span, cementitious slab adapted for floor or like construction, comprising a tongue on one side, said slab having a complementary I groove formed in the opposite side to receive a tongue of an adjoining slab, and a plurality of metallic mesh reinforcement mats embeddedin spaced relationship within said slab, one of said mats being positioned on one side of the center plane of the slab, and another mat being positioned on the other side of the center plane of the slab, whereby either face of said slab is rendered equally adaptable to form the load sustaining surface of a floor or like structure, and at least one of said mats extending into said tongue.

15. A long span, reinforced, precast building slab, comprising a body of plastic material having a tongue extending along one edge of the 'same, reinforcement means adjacent each load sustaining surface of said slab, said reinforcement extending throughout said slab and extending into said tongue and rendering said slab resistant to bending moments in any direction, counte'rdirection or combination of said directions at the same time.

16. In a reinforced, cementitious, precast building slab having a tongue-extending along one edge of the same and adapted for cantilever construction, substantially equivalent reinforc- I ing means adjacent each'load sustaining surface of said slab,said reinforcingextending uniformlei sections throughout said slab, one of said sections extending into said projection, and the apex of said mat extending into said tongue, whereby said sla'b is uniformly strengthened'and said coincident projection and said tongue are rendered resistant to accidental breakage.

FRED A. MANSKE. ROY V. YEAGER.

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