US1817914A - Floor construction - Google Patents

Description

Aug. 11, 1931. K. P. BILLNER FLOOR CONSTRUCTION Filed Feb. '7, 1930 msnm Patented ug. 11, 1931 NITED STATES PATENT ori-Ica KARL E. BILLNER, OF YORK, N. Y., ASSGNO TO THE AEROCBETE COIRIEORATIONv OF AMERICA, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE FLOOR CONSTRUCTION Application led February 7, 1930. Serial No. 426.519.

My present invention relates to ioor con-v struction, and myy object is to vprovide an arrangementbf the flat ceiling type which will be better, cheaper, more sound-proof, and

I more ireeresisting than floor constructions heretofore made. In a practical sense, my improved floor construction is quite sound proof, and entirely fire-proof.

Heretofore, the floor constructionsof the f type I have improved, have made use of a.

framework of relatively structural steel beams, the dimensions of which are determined by the load to be carried, the dimensions of the steel beams and the span thereof. The beams so employed.l are sometimes light steel I-beams, while in other instances they have been open steel trusses consisting of parallel T-beams with an intermediate light steel lattice between them. Good results have also been secured with so-called bar joists, comprising two sets of parallel bars spaced a proper distance apart and connected by an intermediate member passing back and forth between the two sets of bars and welded or otherwise secured thereto at the points of contact. However, the particular construction of these light structural steel beams is unimportant, and the art is familiarwith numerous devices for the purpose, the important considerations of manufacture being to design an arrangement using as little steel as possible, of easy and economical construction and of the proper strength Having set up the structural steel beams to form the support of the floor, spaced a proper distance apart, a slab of ordinary dense concrete is carried thereon to constitute the floor surface. may vbe made of pre-cast sections or it may be of one piece and be cast in situ. When a smooth under-surface is required, a suspended ceiling is fastened in any suitable way to the light steel beams, but manifestly offers no strength to the construction as a whole. y

The fiat ceiling type of oor construction to which I havereferred is' subject to a number of practical objections and disadvantages, whichit is the object of my present improve'- ments to overcome. When there is a suspended ceiling, the construction is fire-resist- This concrete slab ant in a sense for the reason that the ceiling may temporarily resist the heating of the load-bearing steel beams. Such a construction, however, is not tire-proof, and if exposed to a fire of more than temporary duration, the ceiling will soon become damaged, thus exposing the steel beams which will thereupon become over-heated and softened and under the stresses imposed upon'them, they will be caused to twist or be otherwise deformed. Under the eect of a severe and persistent fire, such a floor will be completely destroyed. A

Furthermore, with this type of construction the steel work isl not sufliciently protected against corrosion, the practice being te cover the steel with paint. Therefore, as soon as the film of" paint is destroyed, the steel will be subjected to the corrosive induence of the atmosphere. It is very important that these light steel beams should be e'ectively protected against corrosion, since the exposed surface thereof is very large as compared to the volume, and hence even a. slight corrosion may diminish the load-bearing capacity of the memberv to a dangerous extent.

Owing to the fact that the light weight structural steel beams have a tendency to buckle sidewise in their compressive'section,

when they are subjected to a load, it is not practicable to utilize the maximum strength of the steel in designing the construction. A very substantial factor of safety has to be allowed `on account of the uncertainty as regards the' possible bucklingl of these structural steel beams. In some cases and to avoid buckling, it is the practice to stiiien the construction by the Lse of lateral bracing between the steel beams, but this is expensive and it is ditcult to obtain sucient rigidity in the construction of fioorswhich maybe subiected to vibrations and sudden stresses. Furthermore, such a ioor construction as I have referred to is not sound-proof even when a suspended ceiling is employed.

With my improved construction, I overcome the foregoing objections as I shall presently point out.

In order that the invention maybe betterunderstood, attention is directed to the accompanying drawings forming part of this specification and in which Figure 1 is alongitudinal sectional view of a portion of a fioor embodying my improved construction showing one of the structural steel beams in the form of a double lattice steel truss, and showing also the temporary form in position for supporting the concrete during casting thereof, as I will presently describe. l

Figure2 is a sectional view at right angles to Figure 1 and on a larger scale.

Figure 3 is a plan view of one of the cups used to support the vfiller for the purpose of securing additional lightness andreducing the cost.

In all of the above views corresponding parts are represented by thesame characters,

In the drawings I show the floor asbeing supported between a wall 1 and a heavy longitudinal I-beam 2, the latter being carried in any suitable way. Extending crosswise are the light structural steel beams 3 which may be of any suitable construction. The

form shown is merely for the purpose of illustration and comprises a compression member 4 in the form of a light T-beam, a tension member-5 reversed with respect to the member 4, and a double lattice 6 between the members 4 and 5 and welded o r otherwise secured to the same. This constitutes a very satisfactory, cheap and stron construction. v

Another form of mem er suitable for the purpose would be-light steel I-beams although `these would be'somewhat more expensive and not so strong as the construction described. Instead of either arrangement so-called bar joists may be used with which the art is familiar, each comprising two pairs of steel bars, one pair forming the compression member and the other the tension member of the beam, and" said bars being connected by a rod passing back and forth between the two sets and welded or otherwise secured thereto at the points of contact. `fAs vabove indicated the beams may be of any suitable construction, so long as they provide the desired load bearing capacity and stiffness for the purpose. Usually the steel beams are spaced about two feet apart more or less when the span is of the orderof twenty feet, and generally speaking these steel beams have a d e th-of about eight inches.

nowd-construct a mold or form 8 of wooden planks below the steel beams and extending around the I-beams 2, as shown, as is common with the casting of concrete. Instead of constructing a wooden mold I may use a mold made up of so-called steeltex, suspended from beams 3 and which consists of sheets of paper or very fine metal .mesh attached to and reinforced by a wire` mesh. This form will be located a short distance below the under-surface of the steel beams, for instance, about two inches. I

now pour the concrete mixture into the mold or form 8 so as to entirely cover the steel beams 3 as well as the I-beam 2, if used, so that the eventual level of the concrete will be two inches more or less above the upper faces of the steel beams 3.

The concrete so employed by me is constructed preferably in accordance with the method disclosed by Aylesworth and Dyer, Patent No. 1,087,098, of February 14, 1914. Such a concrete 'may be composed of Port land cement, a suitable aggregate such as sand, water, and powdered aluminum or other material by which the Imass will be aerated before setting has taken place. The aeration, however, can be effected in any other suitable way. A porous concrete so used is very light and therefore cheap, since a relatively small amount of Portland cement is used. Beingrlight it does not impose objectionable strains on the steel beams. It ispractically sound-proof.

It is fire-proof in the highest sense of the word. If subjected to fire, the heat insulating qualities of the protecting layer of por.

ous concrete or aerocrete will prevent the supporting steel beams from becoming overheated. v

vSince the light steel work is entirely enclosed in the porous-concrete all danger of corrosion is eliminated. Furthermore, the solid construction described prevents any buckling in the compressive sections of the steel beams so that expensive bracing is unnecessary, and in designing the lioor a much pmaller factdr of safety has to be taken into account than heretofore.

It` will be understood of course, that, when the concrete has set suiiiciently, the wooden form or mold 8 will be removed, thus producing a smooth ceiling surface. If so called steeltex is used as form material, the form is left in the concrete and serves to create a better bond for plaster which may `be applied to give a smooth ceiling surface.

Instead of pouring a solid slab of porous concrete'as I have explained, it will be possible and in some instances desirable to make. use of very light and cheap fillers occupying Aa considerable portion of the spacewithin `the floor so as to further reduce the costA of construction as well as the total weight. In Figure 2 I have shown one of these fillers comprising a water-tight bag 9 containing a very light material 10, such as granulated slag, cinders, diatomaceous earth or asbestos refuse, all of which have the advantage of being fire-proof. Shavings may also be employed for the purpose, although obviously not fire-proof, or instead of filling the bags with a light Weight material they may be made air-tight and be inflated with air.

When these fillers are employed they are preferably carried upon small metal cups, (see Figures 2 and 3), stamped or otherwise formed, and having channels or passages 12 therein, so that the concrete may enter the same during the casting operation to prei serve the continuity of the lower or ceiling surface.

These fillers are placed side by side so as to occupy as much of the volume as may be desired, and when the concrete is poured the latter being free-flowing will fill all the interstices around the fillers, all of which thus will be completely encased and sealed within the concrete. Although I prefer in every case to make use of porous concrete as explained, nevertheless when these fillers are used, the available spaceswhich are to be filled with the concrete are relatively so small that ordinary non-porous concrete may be employed. If such non-porous concrete is used, it will be desirable to employ as an aggregate broken pieces of porous concrete instead of heavy aggregate, such as stone or gravel, orinstead thereof, a light concrete can be used composed of cement and cinders or cement and granulated slag.

Having now described my invention, what I claim is new therein and desire to secure by Letters Patent is 1. In a flat ceiling floor construction of the type described the combination of light structural steel beams spaced relatively closetogetherl and supported at their ends and a monolithic filling of porous concrete entirely embedding said beams and of a thickness suiiii ciently great .with respect to the spacing of said beams as to give the desired load bearing capacity Without-reinforcement. Y 2. In a fiat ceiling floor construction of the type described, the combination of light structural steel beams of open or lattice construction, spaced; relatively close together and supported at their ends and a monolithic filling of porous concrete entirely embedding said beams and of a thickness sufficiently great with respect to the spacing of said beams as reinforcement.

KARL P. BILLNER.

to give the desired load bearing capacity l without reinforcement. v o

3. In a .fiat ceiling ioor construction of the type described, the combination of light structural steel beams spaced relatively close together and supported atk their ends, fillers consisting of distended bags placed between said beams and a monolithic filling of concrete entirely embeddingfsaid beams and said lillers and of a thickness sufciently great with respect to thespacing of said beams as to give in forcement.

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