US3233378A - Monolithic roof and floor construction - Google Patents

Description

Feb. 8, 1966 J. H. CRUMBAUGH MONOLITHIC ROOFl AND FLOOR CONSTRUCTION 2 Sheens--Sheerl l Filed Nov. 8, 1961 '7 Vol2/Yogi,

Feb. 8, 1966 J, H. CRUMBAUGH MONOLITHIC ROOF AND FLOOR CONSTRUCTION 2 Sheets-Sheel'l 2 Filed Nov. 8, 1961 United States Patent Olitice 3,233,378 Patented Feb. 8, 1966 3 233 378 MONOLTHIC ROOF ANDFLOR CONSTRQCTION .lohn H. Crumbaugh, Clarendon Hills, Ill., assignor to United States Gypsum Company, Chicago, Ill., a corporation of Illinois Filed Nov. 8, i961, Ser. No. 151,091 1 Claim. (Cl. 52--332) This invention relates to a monolithic deck construction and more particularly to a poured cementitious construction employed as either a roof or oor deck.

Lightweight, strong and durable roof decks have for many years been constructed of lire-resistant reinforced gypsum concrete slabs poured in place over permanent formboards. Prior to this invention, however, it had been the practice in the construction of such decks to employ stoel rail-like sub-purlins placed transversely over steel supporting beams or purlins. The formboards were placed between adjacent sub-purlins and simply supported on the llanges thereof. A wire reinforcing mat was then draped over the sub-purlins and iorrnboards, and the gypsum concrete was poured thereover. The maximum spacing between the sub-purlins in this construction was governed not only by the strength of the formboards themselves, but also by the manner in which these formboards were supported on the sub-purlins. Moreover, the formboards presented a discontinuous supporting surface over the entire structure because of the intermediately disposed sub-purlins. The maximum allowable spacing between sub-purlins in this construction governed the number of sub-purlins which were required. Moreover, since the sub-purlins constituted a large part of the weight of the construction, the number of purlins required was governed in large measure by the number of sub-purlins employed. Not only were the steel purlins and sub-purlins heavy, but they constituted a major portion or" the expense of the structure, and consequently ways have been sought to reduce the weight and cost ot the deck structure through the reduction in the number of these members without sacrifice of strength, durability or any of the other desirable qualities of the deck.

In addition, ways have been sought to improve the spanning characteristics of the formboards and to minimize undesirable dellection and sag of the tormboards under weight of the wet gypsum concrete or cementitious lill, a phenomenon resulting from the fact that the wet concrete is quite heavy and does not become self-supporting until after it has set and hardened. While such dellection or sag is rarely considered injurious structurally, it does adversely atleet the appearance of the underside of the deck. Moreover, when such deflection does occur, additional cementitious material is required if a gypsum slab ot' uniform thickness is to be obtained. In a deck of large area the amount of additional cementitious material required to obtain a level uniform slab thickness may be considerable ranging into several tons.

It is, therefore, one object of this invention to provide means which` will reduce the weight and the cost of cementtious roof deck construction while at the same time substantially improving the spanning characteristics and minimizing deflection and sag of the formboards, rall without sacrice of strength, durability or any of the other desirable qualities of the deck.

It is a further object of this invention to provide an improved oementitious deck construction having high strength and durability and displaying uplift resistance comparable to heavier weight constructions.

lt is another object of this invention to provide a cementitious deck construction having an improved underside appearance and requiring less cement in order to achieve a slab of desired uniform thickness.

It is still another object of this invention to provide a roof Ior door construction wherein the formboards have improved spanning characteristics, thus resulting in an economy of materials and erectiontime by requiring fewer supporting members.

It is an additional object of this invention to provide a roof or floor construction which minimizes heat loss by elimination of the steel supporting members which heretofore were disposed within the poured slab.

It is still a further object of this invention to provide a deck construction, the components of which are easily fabricated and easily and economically installed.

Other objects will be seen, and a further understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawings. y

in accordance with one the embodiment of the invention, the poured cementitious deck construction consists of a plurality of substantially parallel supporting members or purlins having fastenenreceiving means thereon adapted to receive and grip penetrating fasteners such as screws or nails which may be driven thereinto. A plurality of forrnboard panels rest upon and span the space between the supporting members presenting a substantially continuous surface for supporting the wet cementitious ll. A plurality of clamping members overlie the support members and the portions of the formboard panels resting thereon, and penetrating fasteners extend through the clamping members and into the fastener receiving means of the underlying supporting members to effect interconnection of these members, so that the ormboard panels may be firmly held between the members.

The clamping members are preferably in the shape of inverted channels, and the side flanges of these members engage the underlying formboard panels while the centnal webs of these members overlie the panels. With the ends of the formboard panels held rmly between the channel-shaped clamping members and the underlying supporting members, the panels are prevented from dellecting under the weight of the wet cementitiousill. Thus, the strength of the construction prior to the setting of the cementitious ll is improved, and the final deck construction is also correspondingly improved. In addition, the construction eliminates the necessity for relatively expensive steel sub-purlins and for additional cement to compensate for formbolard sag; thus, the cost of the deck is substantially reduced, without sacrice of strength or durability.

In the drawings in which like numbers are given to like parts:

FIGURE l is a perspective view of a portion of a monolithic deck construction produced in accordance with one embodiment of this invention;

FIG. 2 lis a sectional view of the deck construction taken substantially lalong line 2 2 of FIG. l;

FIG. 3 is a sectional view of the deck construction taken along line 3,-3 of FIG, 2;

FIG. 4 is a perspective view of a portion of a slightly modied supporting member which may be employed inl the construction of the deck;

FIG. 5 is a perspective view of another modified supporting member, -showing the manner in which this supporting member may be employed with the formboard panels and clamping member ,in the Construction of a deck; and

FIG. 6 is another modification of a supporting member which may be employed in the construction of a deck in accordance with this invention.

With more particular reference to the drawings, the primary vstructural members of the deck construction 10 are the structural steel purlins or supporting members 12. These supporting members are mounted in substantially parallel horizontal relationship and are spaced prefera- 3 bly either 3 or 4 feet on center. Across the tops of the supporting members 12 are placed rectangular formboard panels 14 the lengths of which are such that when installed the marginal ends of the panels will be disposed over the purlins. This length is preferably sufficient to permit the panel to span the distance from about the center of one purlin or supporting member 12 over the adjacent supporting member to about the center of the next adjacent supporting member. Over the panels 14 are placed a plurality of clamping members 16. These .members are positioned in overlying relationship with the supporting members 12, and a plurality of penetrating fasteners such as nails or screws 20 are driven through the clamping members 16 and into the underlying supporting members 12. Over the formboard panels 14 and the clamping members 16 is placed a wire mesh reinforcement 22, and over this entire construction is poured the cementitious ll or concrete 24.

The supporting members 12 may be formed in a variety of configurations. These members, for example, may be in the form of the open web joists illustrated in FIGS. l, 2 and 3. It will be noted that the flanged top 36 of the supporting members 12 presents a rather wide horizontal bearing surface. A recess 32 is formed centrally in and extends substantially the entire length of 'the flanged top 30, land the mouth 32a of the recess is restricted such that when the penetrating fasteners 20 are driven thereinto, they will be resiliently gripped and held fast.

The formboard panels 14 are rigid boards preferably made out of a material such as plasterboard with a set gypsum core 33 surrounded by paper cover sheets 33a or of a material such as iberboard, the selected material having preferably incombustible and/ or insulative qualities. However, any covering suitable for spanning the space between the purlins and capable of supporting the wet cementitious till would be adequate for use as a formboard panel, as long as provision is made for the setting and drying of the gypsum. As best illustrated in FIG. 3, the marginal edges of the panels are preferably tongueand-grooved so that when the panels are placed over the purlins or supporting members 12, they will closely intert :and provide a relatively non-permeable joint between the adjacent panels to prevent leakage of wet cementitious fill therethrough. Moreover, the tongue-and-groove interlocking of adjacent boards substantially strengthens the panels and unifies the structure thereby further increasing resistance to sag and improving the underside rappearance. However, even without a tongue-and-groove arrangement, the abutting formboards form a continuous supporting surface for the subsequently applied wet cementitious fill.

The panels 14 may vary dimensionally according to the spacing between supporting members 12. For example, if the centers of the supporting members 12 are spaced 3 feet apart, the formboard panels should be 6 or 9 feet in length; whereas if the supporting members 12 are spaced 4 feet on center, the formboard panels should be S or l2 feet in length. The panel Width would normally be determined by handling ease. As a general pnactice,

' the panel lengths will range from about 4 to about 12 feet,

and the panel widths will range from about 2 to about 4 feet. about 1/2 inch to 1 inch depending upon the strength required and upon the particular composition of the panels.

The clamping members 16 are preferably constructed of sheet material such as metal or plastic and are substan- The panels in general will vary in thickness from tially channel-shaped., `each having la pair of side anges wet cementitious fill. The gauge may in some instances be light enough to be punctured by the penetrating fasteners, although the web 38 may be easily prepunched in heavier gauge material for the accommodation of the fasteners 20. Twenty-four gauge galvanized sheet steel has been found to be a very satisfactory material from which to make the relatively lightweight clamping members.

These channel-shaped clamping members 1.6, which may be provided in 8-foot long sections for ease of handling, are placed in overlying relation with respect to the supporting members 12, the side flanges 34 and 36 thereof engaging the top -surfaces of the formboard panels 14y and the central web 38 thereof being spaced above the top surfaces of the panels. At those places where twoL panel ends abut and are supported upon one supporting member 12, as occurs on every other supporting member in the preferred embodiment, the clamping member 16 will overlie this end joint, and the side flange 34 thereof Will engage the end of one panel while the opposite side flange 36 thereof will engage the end of the other panel. This is illustrated on the left-hand side of the structure in FIG. 2.

The penetrating fasteners 20 are preferably #S drive screw nails, and these are driven through the central web 38 of the channel-shaped clamping members 16 and into the recessed central portion 32 of the underlying supporting member 12. Where the joints occur between the ends of adjacent formboard panels 14, as illustrated on the left-hand side of the structure in FIG. 2, the penetrating fasteners 2t? will extend through this joint and into t-he recessed central portion of the underlying supporting member. Thus, the ends of the abutting panels are effectively interconnected by clamping them tightly against the common underlying supporting mem-ber 12. Where no end joint occurs, as on the right-hand side of the structure in FIG. 2, the penetrating fasteners 20 will extend through the formboard panel 14 and then into the underlying supporting member 12 to effect clamping of the center of t-he formboard panel. Thus, both the ends and the centers of the panels are restrained, and intermediate deflection and sag is minimized. The fasteners 29 are driven firmly into the underlying supporting member 12, and the resilience of the diverging flanges of the sheet metal or plastic clamping members 16 will result in a constant and resilient clamping action whichwill resist any deflection of the underlying formboard panels.

The reinforcing wire mesh 22 is preferably constructed of 19-gauge strands which are laced to le-gauge wire strands spaced 3 inches on center. After this reinforcing mesh has been draped over the formboards and the inverted channels, the cementitious fill 24 is poured. This cementitious iill is gypsum concrete, preferably composed of calcined gypsum which may have suitable fillers and various well-known commercial additives employed to control set time. Any of the well-known cementitious lls commonly used for roof deck construction may be employed.

The supporting members 12 may vary in form from that illustrated in FIGS. 1, 2 and 3.

Supporting members of somewhat modified construction are illustrated in FIGS. 4, 5 and 6. The modified supporting member 42 shown in FIG. 4 is substantially I-shaped and constructed of concrete. In the top supporting surface is acentral recess in which is dispos-ed an insert 44 ,of a nailable material such as wood. Any nailable material will, of course, be satisfactory if it is capable of resiliently engaging and holding a nail or screw which has been driven thereinto. It will be noted that the mouth of the recess is restricted, thereby effecting a positive interconnection between the member 42 and its insert 44.

The modified supporting member 52 illustrated in FIG. 5 is constructed of a pair of steel channels 54 and 56 having their central webs 54a and 56a projection welded in spaced relationship to provide a recess 60 therebetween.

The webs of the channels are slightly and identically dished such that when a penetrating fastener 20 is driven into the recess 60 and into the dished portion thereof, it will be resiliently held `between the webs of the channels.

The modified supporting member 62 illustrated in FIG. 6 consists of a trussed T having a board or other nailable strip 66 attached thereto by means of a bolt 68. The primary consideration in the construction of the supporting members 12, 42, 52 and 62 is that these members be provided with means for accommodating and grasping a penetrating fastener such as a nail or screw 20 which has been driven thereinto. Many supporting members other than the specific types herein illustrated and described may be employed if provided with such fastener receiving means. The penetrating fasteners are required to hold the clamping members 16 tightly against the formboards 14 to prevent deflection thereof under the weight of the wet cementitious lill.

The formboard panels 14 are prevented from sagging between the purlins or supporting members 12 by the resilient clamping action of the penetrating fasteners 20 and the clamping members 16. In effect, the formboard panels, which are interconnected by both clamping and the tongue-and-groove arrangement, tend to act as a single continuous panel spanning the entire deck construction. With this construction the formboards have improved spanning characteristics, i.e., they may be permitted to span greater distances with less sag than has been heretofore possible with previous constructions; and since the sagging of the panels is minimized, the necessity for providing additional cernentitious lill in order to obtain a uniform slab thickness also is minimized. The result is a more uniform deck which although light in weight is extremely strong and durable. The deck has an improved underside appearance and may be constructed more easily and at a lower cost than other decks of comparable strength. The improved construction is less costly than previous constructions, for not only are the sub-purlins eliminated, but because of the improved spanning characteristics of the formboard panels fewer purlins are required.

The overall construction, although lighter, is neverytlheless comparable in strength, duraibility and upllfft resistance to previous poured gypsum deck constructions which are substantially heavier.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that many modifications and changes in various details may be resorted to without departing from the spirit and scope of the invention, as hereinafter claimed.

What is claimed is:

A poured cementitious roof or floor deck construction comprising in combination a plurality of spaced substantially parallel supporting members having top surfaces which lie in a common, substantially horizontal plane, each supporting member having centrally disposed means extending longitudinally along and downwardly from the top surface thereof to receive and grip penetrating fasteners driven thereinto from above, a plurality of formboard panels having longitudinal marginal edges provided with tongue-and-groove formations, said panels being arranged in substantially coplanar juxtaposed relationship to one another and resting upon and spanning the space between the top surfaces of said supporting members, said panels being oriented with the longitudinal tongue-and-groove edge formations of adjacent panels forming tight edge joints which extend transverse to said supporting members and with the transverse ends of adjacent panels resting on the top surfaces of supporting members in substantial abutting relationship with one another to form end joints which overlie and extend longitudinally along the central portions of said supporting members, a plurality of elongated substantially channelshaped clamping members, each of said clamping members having a central web portion and a pair of side flange portions integral with said web portion and diverging downwardly therefrom, the side ilange portions terminating in free, substantially rectilinear and coplanar edges, each clamping member overlying an end joint and the supporting member therebeneath, the free edges of the diverging side flange portions of each clamping member being in engagement along substantially continuous lines of Contact with the upper surface of the adjacent panels which form the end joint, the central web portions of each clamping member being disposed above the upper surfaces of said panels in spaced relationship with respect to said panels and the end joint formed therebetween, a plurality of penetrating fasteners extending through the central web of each of said clamping members at longitudinally spaced intervals, each fastener having a head portion in engagement with the top surface of said clamping member central web and a pointed end portion extending into the centrally disposed fastener receiving and gripping means of the underlying supporting member, whereby said clamping member may be held down and the formboard panels adjacent the end joints may be resiliently clamped against the top surfaces of the supporting members by the flange portions of the clamping members, wire mesh overlying said formboard panels and said clamping members, and cementitious lill disposed in overlying relation to said formboard panels and encasing said wire mesh and said clamping members, the central web and flange portions of said clamping members being substantially imperforate, whereby entry of said cementitious ll into the space beneath said clamping members is substantially prevented.

References Cited by the Examiner UNITED STATES PATENTS 1,416,888 5/1922 Schumacher 50-211 1,574,304 2/1926 Pawling 50-319 1,740,898 12/1929 Lawrence 50-303 1,900,346 3/1933 Jarvis 50-291 1,909,134 5/1933 Skar 50--291 1,981,314 11/1934 Ellis 50-302 2,002,927 5/1935 VenZie 50-315 2,024,068 12/1935 Shannon 50-318 2,072,882 3/1937 Hogenson 50-194 2,075,514 3/1937 Ellis 50-452 2,083,725 6/1937 Manske et al. 50-390 2,085,472 6/1937 Roush 50--319 2,314,449 3 /1943 Hoggatt 50-45 2 2,410,922 11/ 1946 Balduf 50-303 2,432,622 12/ 1947 Johnston 5 0 406 2,440,053 4/ 1948 Macomber 5 0--3 18 2,711,138 6/1955 Hart 50-267 2,900,056 8/1959 Greulich 50-316 3,073,420 1/1963 Olsen 50--172 FOREIGN PATENTS 231,862 7/1959 Australia.

4,951 3/ 1915 Great Britain.

FRANK L. ABBOTT, Primary Examiner.

WILLIAM I. MUSHAKE, HENRY C. SUTHERLAND,

Examiners.

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