US2705886A - Prefabricated, reinforced floor structure - Google Patents

Description

April 12, 1955 c. E. ANNETT PREFABRICATED, REINFORCED FLOOR STRUCTURE Filed Feb. 26, 1952 INVENTOR. CHARLES E. AN NETT elements making up the composite beam or joist.

United States Patent PREFABRICATED, REINFORCED FLOOR STRUCTURE Charles E. Annett, Short Hills, N. L, assignor to Arthur J. Salerno, Cedar Grove, N. J.

Application February 26, 1952, Serial No. 273,446

4 Claims. c1. 72-68) This invention relates to improvements in structural units, and more particularly, to a new type of structural unit comprising a slab or top flange which forms an integral part of a metal beam or joist comprised of a web and bottom flange. The invention also comprises the reinforcing elements, and forms into which the slab may be poured.

Pre-cast slabs are widely used in construction. They have advantages over the pouring of floors and roofs in position in the structure. The pre-cast slabs have the disadvantage of requiring a relatively long curing time to gain suflicient strength for handling. They also require separate metallic beams or joists to support the concrete slab. Ordinarily, these beams or joists are of such dimension and strength as to make them capable of supporting the concrete slab or sheet and such other structure or live load as may be associated therewith or carried by the slab or sheet. In addition, two construction operations are required, i. e., assembling the steel work and laying the slabs. Such arrangements make for extra weight in the structure but do not make use, to the fullest, of the inherent rigidity and strength of the materials used.

The present invention relates to an improved combination of a joist or beam and a slab of concrete or other poured material as a structural unit to thereby integrate two elements of normal construction into one unit which can be erected and put in place together. The new unit has optimum strength and rigidity and can be readily constructed from available building materials. If desired, the concrete portion can be readily poured on the job and requires less curing time than normal construction due to the bracing effect of the metal parts.

Furthermore, no bridging is required with this type of construction as normally is the case when joist and slabs are separate elements.

More particularly, the structural unit embodying the present invention includes an elongated metal beam or joist of V-shaped cross-section such as, for example, skeletonized lightweight metal, expanded metal, reinforcing bars, rolled bars and rolled or extruded structural shapes. The apex of the V-shaped member, which is directed downwardly when the structural unit is installed, may be fabricated from a T-beam, angle, channel, H beam or other rolled or extruded shape to stiffen the bottom flange and provide the required material to resist the design stresses. The edges of the V-shaped member at the ends of the arms of the V may be constructed of similar rolled or extruded shapes and may be selected to form or provided with a shelf, to facilitate attachment of the slab reinforcement and to provide part of the material to resist the top chord stresses. The concrete slab forms the portion between the ends of the V arms, making the cross-section of the structural unit essentially triangular. This slab together with the edges of the V-shaped member constitutes the top flange. The strips at the upper edges of the beam or joist greatly facilitates the formation of the concrete slab for the reason that the beam may be inverted on a flat or cambered surface and used as a mold into which the concrete can be poured and allowed to set. As a reinforcement for the concrete slab, the opposite edges of the V-shaped member may be joined by concrete reinforcing mesh or rods whereby the concrete slab cast thereon will be joined with the otThlzler e triangular cross-section of the structural unit makes it sufliciently rigid to permit handling and its relatively Mice light weight makes it possible to handle the beam or joist with the usual hoisting equipment employed on a construction job.

For a better understanding of the present invention, reference may be had to the accompanying drawings forming a part of this specification, wherein:

Fig. 1 is a view in side elevation of the structural unit;

Fig. 2 is a sectional view taken along line 2-2 of Fig. l on a somewhat larger scale;

Fig. 3 illustrates a modified form of beam including a T-shaped bar with an inwardly extending flange connected to the metal web and slab reinforcing;

Fig. 4 is a fragmentary perspective view illustrating a modified connecting means for joining the beams or joists in side-by-side relation;

P Fig. 5 is a sectional view taken along line 5-5 of Figs. 6 and 7 are fragmentary perspective views illustrating further modified connecting means for joining the beams or joists in side-by-side relation and modified top edges of the V-shaped member;

Fig. 8 is a plan view of a portion of a modified type of beam showing additional slab reinforcing to resist horizontal shear.

The structural unit B shown in Figs. 1 and 2 has a V-shaped web 10, referred to hereinafter as a beam. It may be formed, for example, by bending a rectangular sheet of expanded metal along its longitudinal center line. Ordinarily the sheet will be several times as long as it is wide so as to form an elongated trough-like member of the V-shaped cross-section. While the web 10 is shown in the drawings as formed of expanded metal, it may also be made of any other shapes or combination of shapes such as, reinforcing bars, rolled or extruded shapes, solid plate, or plates with angle stiifeners.

The apex edge 11 of the web 10, which is directed downwardly in use, may be reinforced with additional metal, such as the T-section beam 12, a channel or angle to reinforce the web against torsional and bending stresses and to increase the amount of material provided to resist bottom chord stresses. The upper or outer edges of the web 10 may be reinforced by means of longitudinal metal bars, strips, rolled or extruded, 13 and 14 which may be provided with upwardly facing shoulders 15 and 16. These may be integral with the webs 10, or may be secured thereto by Welding.

The metal bars 13 and 14 support a sheet of wire mesh 17 or reinforcing rods which are welded or otherwise firmly secured to the bars 13 and 14. The mesh 17, which may be any conventional form of reinforcing for concrete, serves as a reinforcement for a concrete slab 18 subsequently cast thereon and assists in joining the slab with the V-shaped beam or joist to form a complete unit. The reinforcing mesh 17 or rods secure the slab to the webs 10 and prevents endwise movement of the slab between the metal bars 13 and 14.

My invention comprises the metal portions of the unit which may be factory assembled and shipped to the job. The V-shaped member 19 and the reinforcing section 12, if desired, may be factory assembled and the wire mesh 17 may be welded or otherwise secured to the bars 13 and 14 on the job. It may then be placed in an inverted position on a smooth surface, such as the completed lower floor in a building with the edges of the bars 13 and 14 resting against the floor. These serve as a mold for the concrete when poured. Suitable end pieces may then be placed transversely between the bars 13 and 14 and the concrete poured into the area defined thereby. The concrete surrounds the mesh 17 and when set, forms an integral part of the structural unit. Because of the rigidity of the structural unit, the slab and beam can be inverted and hoisted into position with conventional hoisting equipment after the concrete has its initial set. Vacuum lifting devices are not required, as is usually the case when handling incompletely cured concrete slabs. The concrete slab 18 when fully set, is capable of withstanding great compression stresses and is utilized as the compression member of the structural unit. In addition it functions laterally as a slab or deck.

The structural units may be mounted in position in the building in any suitable way, as will be understood by those skilled in the art. The ends of the units may be mounted in or on a masonry wall 2 as shown at 4, or on a steel beam 6 as shown at 8.

The structural member can be made to function as a continuous beam over the supports 2 or 6 by welding the slab reinforcing of adjoining members together longitudinally, and connecting their bottom flanges.

A series of similar structural units may be placed sideby-side with side bars 13 of one unit abutting against the side bar 14 of another unit, as shown in Fig. 2. The units may be temporarily or permanently secured to one another by wire ties 19 as shown in Fig. 2 or may be permanently joined by welding together the adjacent upper edges of the joining bars 13 and 14, as shown at 20.

The T-section beam 12 may be used to support acoustic slabs S or other sheet material forming the ceiling of the floor below. The slabs S rest on the laterally directed flange of a T-section beam 12.

The relative dimensions and the size of the individual components will be determined largely by the length of pourable or moldable to form the slab. Examples ini clude various gypsum, plaster and similar compositions including those with a binder with or without a filler.

The reinforcing structure for the outer edges of web may be modified, if desired. For example as disclosed in Figure 3, the outer web 10 may be reinforced by a T- 3 section beam 21 with an inwardly extending flange 22 to which may be attached a sheet of reinforcing mesh 17.

Fig. 4 and Fig. 5 disclose a modified form in which means are provided for retaining the slabs and beams in in side-by-side relation. In this modification, the side bar 27 of one unit has a series of outwardly extending loops 29 which fit in corresponding slots 30 in the side bar 28 of an adjacent unit and are secured therein by pins or wedges 31 driven into the portion of the loop which extends beyond the inner surface of side bar 28. Before pouring the slab it is desirable to secure a temporary form over the inside female part of the connection which will when removed provide space for the maie part and wedge. This can later after assembly be grouted to restore the full strength of the top chord. It is desirable to fasten the units together to hold them in posit-ion relative to each other as the building is being erected before the concrete is fully cured. Later, it is permissible to weld them together.

A further modification of the retaining means is disclosed in Fig. 6. In this form, the side bar 32 has a series of laterally extending and downwardly curved tongues 33 which extend through corresponding notches; 34 in the upper edge of the adjoining metal bar 35 and engage the inner side thereof to retain the beams and slabs in side-by-side relation.

Retaining means may be modified further as shown in Fig. 7. In this modification, a U-shaped clamp 36 straddles the adjoining metal bars 37 and 38 and is received in notches 41 in the upper edges of the bars so that the upper surface of the clamps 36 is substantially flush with the upper edges of the bars. The side bars 37 and 38 may also be provided with corresponding dimples 39 and recesses 40 to align the two structures. It will be understood that the side bars of the adjoining beams shown in Figs. 3 to 8 can be welded together when the floor or roof is being assembled or after it is finished.

Fig. 8 shows a modified form of beam or joist in which additional means are provided for preventing any possible horizontal shear or endwise movement of the concrete slab between the metal bars. In this modification, the side bars 51 and 52 of a structural unit are connected by a series of V-shaped reinforcing rods or bars 53 which together with the reinforcing mesh 54 are encased within the concrete when the concrete slab is poured.

It will be understood, of course, that other structural parts of the beams are susceptible to modification. Therefore, the form of the invention described above should be considered as illustrative and not as limiting the scope of the following claims.

I claim:

1. A floor for a building structure comprising a plurality of structural units in abutting edge to edge relation, each unit comprising an elongated trough-like beam of V-shaped cross-section having skeletonized substantially flat sides joined at their lower edges and having spaced apart upper edges, said joined lower edges constituting an apex edge, a reinforcing member fixed to and extending along said apex edge and reinforcing said beam against tension, torsion and bending stresses, metal strips secured to the upper edges of said sides, each strip having an upwardly extending side flange and an inwardly extending flange integral with said side flange, metallic reinforcing members extending between said strips and secured to said inwardly extending flanges, a slab of concrete extending between said metallic strips and forming the floor surface and compression member of said beam, said slab bearing against said flanges, having its upper surface substantially flush with the upper edges of said strips and said reinforcing members embedded therein, said strips of said units forming the abutting edges thereof, and means joining the abutting strips of adjacent units.

2. The floor structure set forth in claim 1, in which said apex edge reinforcing member is an inverted T- shaped member having a central flange joined to said apex edge and laterally directed flanges at its lower edge for receiving and supporting the edges of panels forming a ceiling for the building structure.

3. The floor structure set forth in claim 1, in which said means for joining the abutting strips of adjacent units comprises a lateral extension on one of said strips of a unit and a substantially complemental recess in the adjacent strip of an abutting unit interfitting with said lateral extension.

4. A structural unit comprising a trough-like beam of substantially V-shaped cross-section having skeletonized substantially flat sides, said sides having joined inner edges and having spaced apart outer edges, said joined edges forming the apex of said V-shaped beam, a reinforcing member of inverted T-shape cross-section fixed to and extending along said apex edge to form the tension member of said beam, metal strips secured to and extending along said outer edges of said sides, each strip having substantially parallel flanges at its inner and outer edges and a flange at about its mid-portion substantially perpendicular to said parallel flanges, each strip being joined at its inner edge to an outer edge of a side with the flanges at the mid-portions of said strips disposed in substantially the same plane, metallic reinforcing elements extending between said strips and secured thereto adjacent to the mid-portions of said strips, and a slab of concrete extending between said strips and forming the compression member of said beam and having said reinforcing elements embedded therein, said slab bearing against the flanges of said strips and having an outer surface substantially flush with said outer edges of said strips.

References Cited in the file of this patent UNITED STATES PATENTS 1,241,187 Berliat Sept. 25, 1917 1,977,371 Bauer Oct. 16, 1934 2,178,097 Davison et al. Oct. 31, 1939 2,310,442 Knudsen Feb. 9, 1943 2,558,946 Fromson July 3, 1951 FOREIGN PATENTS 11,011 France Nov. 26, 1909 513,620 Germany Nov. 29, 1930 36,543 The Netherlands Oct. 15, 1935 628,626 Great Britain Sept. 1, 1949

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