US1679599A - Building construction - Google Patents

Description

- P.-H. BEVIER BUILDING cSNs'rRUcTIoN Aug. 7,1923..y i I 1,679,599

Filed NOV. 9, 1925 ATTORNEYS Patented Aug.v 7, 192s.I i

7 UNITED STATES .PATENT OFFICE.

PH'ILIP H. Biivinn, or n'nooxLYN, NEWfvYoax.

BUILDING coNs'rR'c'rroN.

Application filed November 9, 1925. Serial No. 67,721.

' of concrete whichfform, in effect, joists or beams, and in which are imbedded steel rods. The concrete joists with the steel rods imbedded therein extend in two directions across the ioor at right angles, this being known asa two-way reinforced floor.

In a iiooi of one'simple span, thecompression in the iioor structure or beam, due to the weight of the structure itself, and the superimposed load which itcarries, isy greatest atthe upper surface of diminishes uniformly toward approximately the center at a line or plane knownas thev neutral axis. y At the neutral axis `there is neither horizontal compression nor tension. Below the 7 neutral axis the tensionstresses increase toward the lower side where the steel'reinforcement is located to resist them.

In a floor with continuous spans, where the steel members are carried over thek supporting girders, the compression stresses occur as before in the upper portion but over about one-half of the entire central portionof the span, while fora distance of approximately one-fourth ofV thev span from each support or girder, the compression Vis greatest at the bottom and Vdiminishes upward to the neutral axis, above which the stresses are tensional, and consequently inv these portions of the floor the steel is placedv near the top to resist the negative bending moment over the supports. Y

From this it will be seen that any floor construction to be entirely safe and economically designed must make provision for this reversal of stresses. p

According to the principles of my invention, in both of the above cases, the compressive forces vare resisted by the combined concrete and tile and equal ultimate strength can be secured either at the top or bottom of the iioor structure.

The principal object of this invention is to provide anew and improved construction of a'twofway hollow tile and reinforced concrete floor, particularly adapted to give the greatest, strength inall portions of the floor.

the floor andV Considered more specifically, thev object ,of the invention is to provide in a floor construction of the type referred to, a plurality of slabs placedat the open ends of the hol- *low/tiles in such a manner las to insure the `presence of asolid mass of concrete between" the adjacent-ends of the tiles and in direct contact with them eitherv at top or bottom lso-as to resistthe compressive forces according .to the strains upon the floor strucvtureat each particular region thereof.

Another object of the invention is to provide a new and improved device for holding the slabs properly in position, while thek concrete is being` placed between the tiles to form the concrete joists of the floor structure. These and other objects of the invention will appear more fully from the following more detailed description andl by reference toy the accompanying drawings forming apart hereof and w ereinFig. l is a perspective View of a portion ofY a floor con'` -structionrembodying myinvention; Fig; 2 1s a section on the lines 2-2 ofV Fig. 1 Fig. 3 is asectioii upon a reduced. scale throu h a portion of a typical continuous,

span oor construction; Fig. 4 isa plan view of a portion of the s an shown in Fig. 3; -Fig.` 5 is a section on t e line 5-5 of'Fig; 4; 6 is a section similar to Fig. 2 showing an application of my invention to an all tile ceiling floor construction; Figs? and 8 are sectional views of a slightlymodified ally tile ceiling fioor construction corresponding respectively tothe showings of Figs. 2 and 5. x sshown in Fig. l of the drawing', the

^ floor is constructedof the open ended hollow tile 10 arranged at spaced intervals. In the spaces formed` between the tilesvthe concrete 11 is poured or tamped, thus forming, in

effect, a plurality of concrete joists extending at right angles to and intersecting .each other.. Imbedded in each of the concrete Joists is a steel reinforcing rod 12, the rods vextending in onegdirection being. placed above and preferablyresting upon the rods which extend 1in `the other direction, as

clearly shown in Fig. 1 of the drawing.- In

. order to preventthe concrete from entering the open` ends of 4thehollow tiles 1 0, I provide slabs 18v preferably constructed of con Vcreteor fire clay, although said slabs may be constructed. of any suitable material havingv -suiiicient'strength and rigidity. The height of each slab preferably is less than the height of the. hollow tiles by an amount about equal i in CII

to the thickness ol the tile shell, while the length ot each slab is less than the width of the tile by an amount about equal to the thickness et' two tile shells. When the dimensions ot the slab relatively to the tile are, as stated above, it will be seen that if a slab is placed on its edge with its liat face in contact with the open end of the tile, as

shown'in Fig. 1 ofthe drawing, the slab will to close the open ends thereot, and in order to holdthe slabs in position, duringthe time the operation olAI forming theconcrete joists is carried on, I employ a spreader 14' c0nstructed of a relatively thin wire, having 'sufficient resiliency to hold the slabs firmly pressed against the ends oi the tiles,

Each of the spreaders lll is proviiiled adjacent toits ends with a double right angled bend which forms a short horizontal portion 15,'and a short` vertically extending portion 16; the horizontal portion 15 being placed upon the upper edge of a slab 13 and the vertical portion engaging the side :tace of the slab.

In order to incrcasethe resilient properties ofthe sprcadcrs and also to permit them to be adjusted readily to different lengths, l `form the central portion with al' loop 17 which may be in the l'oiin of a re-entrant bend asshown in Fig. 2, or which may be in the form ol" the circular loop 17, as shownin Fig. rlhe loop 17 or 17'LL in addition serves to bring` the center 'of gravity of the spreader well below the horizontal end portion 15 et the spreaders so that when the spreaders are placed in position upon the vslabs they will always hang in their intended position in a condition of stable equilibrium. The use or resilient sprcaders instead of rigid members for holding the slabs in position during the operation Aof 'forming the concrete oists not only insures that the slabs will be more securelyheld in position, but also permits the spreader-s to yield under compression, thereby insuring that the compression stresses will be resisted by the concrete el? the j oists and not to any appreciable extent by the spreaders.

rlhe method of constructing a floor in accordance with the principles of my inven- (ill porary centering or supporting boards 18,

and the rein'liorcing reds 12are laidacross in the spaces between the tiles, after which the slabs are stood vupon their edges so as to extend vertically in contact with the open ends of the tiles, a spreader 111` being placed over the top edges ot the slabs to hold themV `19 and 20, the slabs` are placed so that their' ripper edges lie in the same plane as the upperjouter laces of the'tiles. i

rlhe construction preferred for a simple span or the central portion ot a continuous span is shown more clearly in Figs. 1 and 2Y of the drawing, from which it will be noted' that the upper edges of the slabsterminate substantially in the same plane as 'the inner tace of the upper shell 10, thus leaving the ond walls of the upper shell 10a uncovered by the slab. As heretofore pointed out, the

length. ot the slab is less than the width ontv the tile by an amount equal to approximately double the thickness of the tile shell, and the slabs are placed centrally ot the -tiles so as to leave the ends of the side walls 10", 10, uncovered. i

ln order to hold the slabs properly in the upper position they are intended to loccupy in a continuous span construction, asv shown in Fig. 3, inthe quarterspans adjacent to the gir- ders 19 and 20, I provide a plurality et shortlengths of relatively thin wire which term carriers 21. rlhe length et these carriers is slightly greater thanrthe spaces between the tiles, and said carriers are placed with their ends projecting into the cells of the tile so that they are supported by the inner face ofthe lower shell et' the tile. Two carriers are' preferably placed across the space 'between two adjacent tiles, so as to bridge this space, and the lower edges of the slabs are placed upon the carriers,I thus bringing the upper edges of the slab in substantially the same plane as the upper lace el the tiles, as shown in Fig. 5 ot the drawing. With the slab held in this position, it will be seen that the end faces oit the lower shell oi the tile will. be uncovered.' tiles are placed in position,fthe concrete is then placed in the spaces between the tiles to form the concrete joists 11. As the metal carriers 21 are constructed of relatively thin space or opening between material the the lower edge or` the slabs, when they are supported in the manner shown in Fig. 5, is not large enough to permit any of' the concrete to flow into the cells of the tiles, the opening being` but slightly larger than the grains of the concrete mixture. The entry et the concrete'into the ends 'of the cells, when the carriers 21 are employed, is fur-` thermore most unlikely, because the lower edge oi the slab projects outwardly beyond ritter all of.v the llt) the line of possible entry of the concrete-into the tile cells, so thaty when the concrete `1s vpoured it could not flow directly towardsthe opening, Vbut would `have* to be, pushedv upwardly from below the lower end of the lslab to enable it to liow or be forced. into the tile cell. Y 1 v n Analyzing a floorconstruction as disclosed above, it will be noted that in the central portieri of a span where the compression stresses are located above the neutral axisv c Thel sides of the slabs are preferably grooved or scored as indicated by the reference character 13a, so that the concrete will adhere stronglyto the slabs lto form therewithan integral uIiitarystruCture, whereby the concrete and tiles will yact together in resistingcompression and shear. Vith the structure shown, it will be noted that in the lirst case, i. e., slabs in the lower position, the concrete `ofthe joists ll contacts withl the end of the tile shell along the entire top shell x u and the entire side shellsv 10", 10F, while in the latter case, i. e., slabs in the upper position, the concrete of thejoists .contactswith theentire area of the end of the bottom shell and the ends of the side shells 10" and 10c. In addition,-in both cases'the concrete contacts with the entire area-of the side faces of the slabs Compression strains in the direction extending longitudinally ofy the tiles are therefore resisted by the full width of the concrete lioists, the two lvertical shells at the sides of the tilethe top shell of the ,tile and the slabs which Contact with vthe ends of the two shells andwhich slabs are backed up by the interior vertical webs ot the tile.` In the. case of compression atright angles to the iormer, the resistance is offered by the full width of the concrete joist, plus the transverse cross section 'of the's1abs` at Veach side'ot the joists, ,plus the horizontal shell of the tile, either the top or bottom she-11depending upon whether the compression yis y above or below the neutral axis'respectively.

It will be seen that the structure herein disclosed will offer greater resistance to vcompression transversely of the tiles than where thin metal sheets are employed for closures tor the ends of the tile cells, because in the Vlatter case, the compression strains are resisted only bythe concrete joist and thetop shell of the tile.` Therefore, by the use of my construction I secure the advantage ot' the compressive strength of the two slabs,

which'is vfrom 300() to 500() lbs. per square inch of surface. v

lrVhere noclosures are provided for the open endsof the tilev and the concrete'l is permitted to flow into the tile cells, the'concrete forms la small right angle triangular Vprism having its base at the bottom and its apex at the top of each cell opening, ro-

vided, however, that the ideal conditions with respect to theconsistencyof the concrete and its manner of application are adhered to. vInv many .'cases, however, because of 'the character of labor employed, and the lack of carefulV supervision, ideal vconditions are not adhered to and if'the concrete mix is too thin, large quantities ofthe concrete may How into the cells until Athe cells are almost entirely lilled. This increases to a dangerous extent the dead load carried by Athe frame andv foundations of the building.

Even when the ideal conditions are maintained,.. the triangular concrete plugs, formed in the'ends of the tile cells, are of very little value for resisting compression strains located above the neutral axis and extending atrightangles to the length of `the tile, because the apex only of the triangular yplugis located inthe region where the compression 1s greatest.

In Fig. c of the drawing I have'shown ymy invention as applied to 'a floor Construction invwhic'h an alltile ceiling is desired.

vAsshown in thisfigure, a ceiling tile 25 is placed between the two adjacent slabs 13 at the lower endfthereof. Y The tile 25 isv Vthe tile iniposition.

In Figs. 8 and 9, I have shownran all'- tile ceiling construction in which the principles for" continuous 'span constructions Vhereinbetore described are cmployedrand by means of which the concrete is most ad-y vantageously placed p with-,relation to the tilesfor'resisting compression at'the top or bottom of vthepfloor construction. As shown in saidv figures the lower edges of the slabs l'lare 'beveled or chamtered as indicatedy by the numeral 30. In, Fig. `8 the slabs 13 are soL placed that the vupper shell of the tile is uncovered by the slab, while in Fig.l `9,- the'slabs are supported by the carriers 21 tact with the ends of the Alower shell ofthe tile. Y i 1.

12oL l (lll It will be understood that the-constructional examples herein disclosed are merely illustrative, and that many changes, variations and modilicationsmay be resorted to without departing from the soiiit of my invention.

As has heretofore been pointed out, my invention is not limited tothe use ofslabs made of concrete or lire clay, but that plates made of metal, card board, liber board, or other suitable material may be employed therefore,.l wish it to be understood that the term slab as used in the claims hereinafter appended is intended to refer to relatively thin plates of the type above described as well as to thicker slabs of concrete, lire clay or the like.

I claim:

l. A reinforced concrete floor construction comprising a plurality of hollow7 tiles arranged in spaced relationship, and l reinforced concrete joists extending across said floor between said tiles, rigid slabs contacting with the opcnends of said tiles, the area of a flat face of each of said slabs, relatively to the cross sectional area of each of said tiles, being such that each of said slabs will cover and act as a closure for the entire open part of the end of the tile to prevent ingress of concrete into the tile cells while leaving exposed a portion of the side and top walls or shell of the tile, against which the concrete of the joists abuts, and resilient means to force and hold said slabs with a resilient pressure against the tile ends.`

2. A reinforced concrete floor construction comprising a plurality of hollow tiles arranged in spaced relationship, and reinforced concrete joists extending across said floor between said tiles, masonry slabs contacting with the open ends of said tiles, and resilient means engaging the outer faces of said slabs to hold said slabs in contactywith the tile ends. y

3. A reinforced concrete licor construction as set forth in claim 2in which said means comprise spreader-s, each of which is constructed of a length of spring metal having the ends thereof bent to provide substantially horizontal portions, the length of each of which is approximately equal to the thickness of a slab and a substantially vertical portion to engage the side face of the slabs, said horizontal portions resting upon the tops of a pair of slabs and supportingthe spreaders, and said vertical portions holding` the slabs .in contacting` engagement with the endsof the tiles.

ll. A reinforced concrete floor construction as set forth in claim 2 in lwhich said means comprise spreaders, each of which is constructed of a length of spring metal having the ends thereof bent to provide substantially horizontal portions, the length of each of which is approximately equal to the thick- 5. A reinforced concrete floor construc-y tion as set forth in claim l, in which in certain regions of said fioor where the ycornpression is above the neutral axis, said slabs are so placed relatively to said tiles as to eX-' pose the ends of theupper shells of the tiles, while in other regions of said floor, where the compression is below the neutral axis, said slabs are placed relatively to said tiles to expose the ends of the lower shells of the tiles.

(l. ln a reinforced concrete floor, the combination with a'plurality of hollow tiles arranged in spaced relationship with reinforced concrete `ioists extending across said floor between said tiles, of a plurality of slabs .for closing the open ends of said tiles to prevent ingress of concrete to the cells of said tiles, the width and length of said slabs being less respectively than the height and width 'of said tiles, and carriers upon which said slabs are supported, said carriers being supported Y by said tiles and extending across the space between the open ends of adjacent tiles.

7V. .ln a reinforced concrete floor, the coinbination with a pluralityrofhollow tiles arranged in spaced relationship with reinforced concrete lioists extending across said floor between said tiles, of a plurality of slabs for closing the open ends of said tiles to prevent ingress of concrete to thecells of said tiles, the width and length of said slabs being less, respectively, than ythe height and width of said tiles, carriers upon which said slabs are supported to hold said slabs with their upper endsin vthe plane of the upper surface of said tiles,` said carriers being providedin those regions of the floorwhere the compression'stresses are located above the neutral plane and being omitted in those regions where the compression stresses are below the neutral plane, in which latter regions the lower ends of the slabs are'located in the plane of the lower surface of the tiles.

8. A reinforced concretefloor as set forth in claim 6 in which means are provided to hold said slabs securely against the ends of said tiles.

9. A reinforced concrete floor as set fortl Y in claim G in which said carriers are con structed of thin material.

l0. A Reinforced concrete :door as set fo in claimf in which resilient spreaders are Whether the compression stresses lare located provided to hold said slabs securely against `above or below the neutral axis, so as to eX- the ends of said tiles. v pose a portionof the tiles adjacent to the 10 l1. A. reinforced concrete floor construo-k tops or bottoms thereof respectively. 5 tion as set forth in `claim l in which, in .difvIn testimony whereof I have hereunto set ferent regions of said floor, the slabs Aare my hand. located relatively to the tiles, according to v PHILIP H. BEVIER.

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