US1049702A - Concrete structure. - Google Patents

Description

C. B. GRADY.

CONCRETE STRUCTURE.

APPLICATION FILED P21119, 1910.

Patented Jan. 7, 1913.

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v Inventor.'

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CHARLES BENEDICTGRADY, OF WEST ORANGE, NEW JERSEY.

concnn'rn strnnc'runn Specification of Letters Patent.

Patented Jan. 7,1913.

Application led February 19, 1910. Seriall No. 544,728.

To alt whom it may concern Be it known that I, CHARLES Bnnnnio'r GRADY, a citizen of the United States, residing in West Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in C oncrete Structures, of which the following is a specification. p i

My`inventi`on relates to' concrete structures `and more especially to a floor vconstruction forvbuildings and the like.

Among the objects of the present mvention are to cheapen and simplify the erection of a Ibuilding having concrete iooring, and more especially with relation to such when of a light construction not intended for carrying excessive floor-loads.

In carrying out the above objects I have invented a novel concrete flooring which, as shown, is to be made up. of girders or the like, together with floor-slabs, the latter being preformed, that is previously made in the shop or elsewhere before being set into lace. p-I will first describe one form of concrete structure embodying my improvements and will then point out the novel features in the claims.

In the accompanying drawings, Figure 1 shows partly in sectionand partly in elevation, a couple of girders and Hoor-slabs embodying my improvements, the section being taken on the plane 1-1 of Fig. 2. Fig. la represents substantially a continuation of the structure shown in Fig. 1, .illustrating the opposite end ofthe slab and containing certain modifications' and details. Fig. 2 is a section taken upon the plane 2--2 of Fig. 1'.

"Fig, 3 is a detail sectional view of a part of `trating a modification the construction shown in` Fig. 1, but illusthereof. Fig. 4 represents a modification, said view bein gra section upon the same vertical plane as Fig. Q. Fig. 5 represents,'b means of a similar sectional vlew, a stil further modification.

Fig. 6 represents in a similar sectional view a still further modification.

Similar letters of reference designate corresponding parts in the several figures of the drawings.

Generally speaking a floor embodying the present improvements is one which consists vof irders extending from column to column, an Hoor-slabs extendin from girder to girder, there being prefera ly a series of parsucceeding girders l floor-Slabs.,

,preformed floor-slab' which al'lelslabs set between each pair of opposite g1rders so as to cover the entire floor area; and 'between each of those girders and the othersimilar series 'of In a eneralway my present improvements re ate to the subject matter set forth 1n my prior Patent No. 902,651, issued Nov. 3, 1908. By a floor-slab I mean a floor member which has substantially the follow- 1ng characteristics, namely, that its top surface is to be a portion'of the floor, and that it is to have a substantial width as compared with its length in contradistinction to the proportions of an ordinary floor beam. The above definition,however, does not preclude the frequently used expedient of a supplementary layer of concrete or other material which 1s superimposed above the floor-slabs after the latter have.had laid on topof them piping, wiring or tiling as may be desired.

The present 'invention is shown embodied in floor-slabs which are of such a character as to extend from girder to girder, one slab spanning the entire distance and having also such depth and strengthening means that -the use of floor beams is unnecessary.

Referring to the drawings hereof A represents a girder which may be of any variety,

:but is shown as a composite member built up of concrete with embedded metal parts. As shown the girders are preferably rectangular in shape and the embedded structure comprises a tension portionyA, a compression p ortion A2 and bolts A3 connecting saidtension and compression portions. The compression portion should be less in cross-sectional area than the tension portion since the concrete above the neutral axis of the girder will resist a part of the compressive strain. In Fig. 1 is shown a simple. I-beam A4 for a girder.

B represents one of the floor-slabs embodying my present invention, and C re resents another one on the opposite si e of the girder and used -for convenience to.

illustrate a simple modification of structure. Referring now to the floor-slab B, it is a ma be made. in the shop in its work-wise position, that with the same side up as shown in the drawings; and said slab extends from one to the other of vtwo oppositely disposed girders.`

Said slab B consists of a mass of hardened `concrete having embedded therem at least and one metallic structure having the characteristics hereinafter to be described. In its general form the slab has a body portion, which is the flat upper portion B and as shown at least one depending concrete rib B2, each of said ribs designed to embed one of the interior metallic structures. Referring to Fig. 2 it will be seen that beneath the bod portion B are arranged two of such ribs B2 in parallelism. The body portion may have a greater length than that of the ribs so that as shown in Fig. l it will extend beyond the ribs at B2, this extending portion forming a projection which may rest directly upon the top of the girder A. The bearing thus obtained will be sufficient to holdlthe slab in place during the process of erection, but as will hereinafter appear, Ihaveprovided additional supportfor the slab. VIn addition to resting upon the girders top, as just explained, the slab may otherwise engage the girder, for instance the lower corner of each rib may be engaged in a recess or seat formed in or pro'ecting from the side of the girden bming now to the metal interior of the slab this comprises, as already stated, at least one metallic structure, which structure extends longitudinally for substantially the entire length of the slab. In detail the structure comprises principally a` tension portion which is shown as a horizontal bar of round cross-section embedded in the concrete and located substantially below the neutral axis of the slab; together with an upwardly extending portion D which is/also embedded in the concrete and is located near the end of the slab or of the ribs thereof, and

said upwardly extending portion emerges' and projects from the concrete at or near the end of the slab. There of course will be a similar upwardly extending portion at each end of the slab. The projecting portion D2 of the metallic structure is intended to be connected to a similar projecting portion of an oppositely disposed slab,` said connection being made by a metallic tie which extends across ,and above the girder, there being means for attaching the tie at one or both ends so as to said projecting portions D2.

E represents a tie which extends across above the girder, it being perforated at proper points So as to permit it being attached to the projecting portions D2 pair of opposite slabs. For convenience the connecting tie E is made in the form of a channel bar with the flanges thereof projecting upwardly.

e metallic projecting portions D2 are shown as provided with screw thread-` adapted to receive nutsfso that the perforated tie-bar' E when engaged over two of the projecting rods D2, can be there securely attached by screwing the nuts D3 permanently connect theA of a.

. wlth contact with the bottom of the channel bar. In this position the tiebar has beneath it the concrete portions B"1 at the ends of the slab body, and these latter rest directly upon the top of the girder so that support for the tie-bar is obtained from the girder. The tie-bar in turn through the connections already described aiiords a stron support for the metallic structures embedded 1n the slabs, which support will bevample for any ordinary strain.

Beneath the tie-bar E is seen to exist a space bounded by the top of the girder and the ends of two opposite slabs. This space can be filled in with concrete or grout after the slabs have been duly connected in their final resting place. As already indicated,

Iirmly down into piping or other articles may be laid above the slabs and the same lilled or covered with further concrete or other material to any desired depth.

The metallic structure heretofore referred to may be made of various shapes, the preferable one being that shown in the right handslab of Fig. l, in which the upwardly extending portion D is substantially vertical; although said portion may be given an inclined position as shown 4at D4 in the left hand slab 0f F ig. 1. I find it economical and desirable to have the structure consist :of a simple bar of round crosssection, although I do not limit myself in this respect. When integral throughout its length the bar will be bent at its ends so as I to change its. direction from the horizontal to the vertical, and by substantially iiat-v tening the metal at the point F, where the bend occurs, this affords a broad bearing surface which precludes the metalV cutting 1nto the concrete and thereby adds to the durability and resisting powers of the slab. Inl a case Where the metal was not integral throughout its length, the same effect would be obtained by equivalent means, namely by having the metal flat where the tension portion and the upwardly extending portion of the interior structure meet each other.

In F ig. l2 is shown a variation which may be employed where a girder A4 is at the outside of a building, and there is therefore noopposite slab. In this case the tiebar will be used, but being differently constructed is designated E. At its right end instead of connecting with the metallic projecting portion D2 of a slab, it connects a special screw threaded bolt E3 passed through the flange of the girder or other convenient point, the nut E4 at the upper end of the bolt serving to engage the top of the tie-bar as before, thus simulating as far as possible the conditions existing at the left hand of Fig. 1.

In addition to the parts above described, other devices of Various kinds may be added,

as'for example supplementary strengthening means may be embedded in the concrete.

Thus a large meshed wire cloth Gr may be arranged horizontally inthe body portions of the several slabs and I prefer to have such wire cloth extend beyond the ends of the slab, as shown at G', so that when the supplementary lfilling of concrete or grout is poured in beneath the tie-bars E, the same will harden abeut and embed the project-- when making the ing portions G of the wire cloth. In addition theretoreinforcing rods or stirrups may be employed, as for example the stirrups I-I, indicated in Fig. 1, which pass downthrough the concrete around the tension member and upwardly, thus helping to strengthen and render more rigid the assembled parts.`

With respect to the action of the tie-bars E, not only do they serve to transmit, as already explained, a portion of the re-action from each slab to the girder, but they also serve to tie together two opposite slabs and at the same time to tie said slabs to the girder, thus preventing` relative horizontal movement between any two of them.

A modification may be adopted with respect to the seating of the slabs B upon the `girder A, as shown in Fig. 3. By this modification the slab is enabled to be dropped so that its upper surface is substantially flush with the upper surface of the girder; and4 this is accomplished by employing a metallic seat b which is to be used -in lieu of the concrete projection B3 of Fig. 1. Said seat b is partly embedded in the concrete at Y of each of the ribs B2 of the floor slab, and at its upper end extends horizontally above so as to rest or seat upon the upper surface of the girder, thereby holding the slab in place during erection.

Referring now to Figs. 4, 5 and 6, showing three different variations from the main form of the invention as shown in Figs. 1 and 2, it should be stated that the tie-bar E and the other devices connected or cooperating therewith, may beemployed in all of the modifications. In fact the views of Figs. 4, 5 and 6 may be practically considered as substitutes for Fig. 2, although Fig. 1 would of course have to be modified in an obvious way to-suit the changes contained in the views of Figs. 4, 5 and 6.

In Fig. 4, the floor-slab is designated J, it consisting of the body portion J and the depending ribs J 2. There should be at least two of such ribs, and as shown the width of the body portion J is substantially the same or no greater than the distance between the two ribs J2, J2, so that said ribs come at the extreme side edges of the slab instead of at intermediate'point-s, as seen in Fig. 2. i Among the advantages of this construction is the following. namely, that slab in the shop, the same can be provided with a bottom surface extending from rib to rib'; the result being that when the slabs are put in place, said bottom surfaces will substantially constitute a ceiling and obviate the very great expense that is usually incurred in constructing and setting in place the ceiling which is to be made to 4depend fromfloor beams or ribs previously set up' in the construction. In Fig. 4 the bottom surface of slab J e is indicated at J3 and is shown as a'thin, composite ceiling-slab, this giving the result that the article as a whole is hollow, having the form of a square box.

Embedded in the ceiling port-ion J 3 is a metal strengthening means in the form of a large meshed wire cloth j', which in the process of manufacturing the floor-slab, is caused to be engaged or' tension portion- D, as shown at j Fig. `4.

In this way the different portions J J 2 and J 3 of theeoor-slabs are made substantially integral or unitary.' By forming the ceiling portion J 3 separately in point of time grade of material, for example, a concrete made from cinders instead of stone, this being not only less expensive but lighter in weight, and at the same time adequate for its purposes, as little strain is to be borne by such part,

The slab just described may be manufactured as follows. The bottom portion J3 is firstcast on a flat shop Hoor. A collapsible form is then placed above it and the ribs J 2 and body J are then cast preferably before the bott-om portion has set. The form is then withdrawn through one of the open ends (which can be done in the shop where it would be' impossible if the floor were manufactured at the building site in the usual manner); the concrete is allowed to harden sufficiently to be handled and then the slab is ready to be shipped to the building. The bottom portion or ceiling-.slab J3 is preferably composed of a concrete lighter in weight than the body and ribs, as previously stated. For instance the body and ribs might be of stone or gravel concrete and the portion J 3 of cinder concrete. With a lioor composed of such slabs, no metal lath or furring rods are necessary and the ceiling will have much better fire-resisting qualities, besides which the dead weight of the floor will be very light as the metal reinforcement G for the slab body B may be placed nearer the bottom than is the coinmon practice. slab will protect the body from fire.

With such a4 flooring, the work at the building is greatly simplified, for one reason amon others that after setting the girders an only a solid ioor loads, but also a there 1s a broad wound around thefloor-slabs in place, we have not 4 capable of carrying heavy This is because the bottom structural difference between the above described fiooring and a flooring which is composed of girder's, floor beams set between the girders, and small hollow tiles or blocks set between said floor beams, this latter construction being more complicated and expensive, partly because necessitating special floor beams which are dispensed with in my invention. The fact that the Hoor-slabs embodying the modification of my invent-ion shown in Fig. 4, are ofthe preformed species, is a very important one, for as already intimated a oorof this particular construction could not be built n situ, since it would be impossible to remove the knock-down structure or forms that can be used in the shop or factory; the girders and other parts of the building being in the way.

A floor constructed with Hoor-slabs such as that of Fig. 4 above described, wherein the ceiling portions are embodied in the preformed slabs, is very much superior in point of convenience and labor as compared with a flooring of a form like that of Fig. 2, following the erection of which costly and elaborate ceiling supporting means may have to be employed, as well as the need of labor in a place inconvenient and more or less dangerous to the workmen,

Coming now to Fig. 5, this construction embodies some of the advantages of Fig. 4, namely in that it provides in the preformed construction a ceiling surface; but this is obtained in a different manner. In this form the Hoor-slab K has its body portion K and the side ribs K2, lK2 all formed of strong hard concrete and the ribs, as before,

embedding metallic structures having ten' sion portions and means for connecting across a girder to another floor-slab by means of a tie-bar E. The floor-slab of Fig. 5, however, is not of a hollow construction as in Fig. 4 but has the entire space between the ribs K2 lilled u with a species of concrete lighter in weig t, for example, a concrete in which cinders take the place of stone. This interior yport-ion is represented at K3, it being flush on the lower side at 7c so as to practically constitute a ceiling.' There will be suiicient adhesive power between the different concrete portions to ef fect the adherencethereof, but if desired any ordinary expedient could be adopted to assist therein, such for example as ridges or' roughened places upon the ribs K2. y

ln the modification of Fig. 6 the const-ruotions previously described are simplified mainly by dispensing with the formation of the-side concrete ribs K2 of the same material and at the same time with the formation of the body portion K. In the latter lformation the `slab L has its body portion L and has the interior metal structures com- 6'5 prising the tension portions D, but in this case said metal structure is embedded partly 1n the hard concrete L and partly in the lighter species ofconcrete L2 which extends from L down to the ceiling surface Z.

The different forms of slabs shown in Figs. 4, 5 and 6 above described, Amay be manufactured in any appropriate manner, but lI prefer ,that they should be made in a work-wise position, that is with the same side'up that the slabs will assume when in `final position. In such case the cheaper or lighter form of concrete, namely that at J3, at K3 or at L2 will be first poured into the form, followed subsequently by the application of the hard concrete constituting the more important portions of the Hoor-slab.

Referring further to the co-action of t-he girders and floor-slabs; the top metallic re inforcement A2 of the girder A is less in area than the bottom member A for the reasonlthat the concrete of the girder will take care of a portion of the compressive strains above the neutral axis as heretofore stated, and also for the reason that after the floor-slabs have been placed upon the girder and the spaces between the slabs have been filled with concrete or grout, the top portions of the slabs will co-act with the top portion 'of the girder and also take a portion of the above referred to compressive strains. The projecting ends of the bolts A3 and also the metallic ties E, serve to augment this co-action, and other means may be added.

Vhere'in the claims it is stated that the metal of the reinforcement of the floor slabs emerges from the concrete substantially at the sla-b ends, it is intended to include an emerging thereof either immediately at or approximately near the slab ends.

What I claim as new and desire to secure by Let-ters Patent is:

l. In a concrete floor member, a reinforcing structure comprising a substantially horizontal tension portion and a bent up portion near the end of said floor member, the same being of round or thick construction for the greater part of its length but being thin or flattened in the vicinity of said bend.

2. Ina building, a floor comprising oppositely disposed girders, in combination with a plurality of preformed floor-slabs, each of sald floor-slabs set between and extending from girder to girder, and each floor-slab consisting of a mass of hardened concrete embedding a metal reinforcement, the metal of said reinforcement emerging from the slab to where the latter obtains support from the girder, and each slab comprising a reinforced body portion, at least two reinforced ribs depending therefrom, and a flat bottom portion connecting the bottoms of said ribs, said bottom portion being com- -concrete substantially at the ends of the posed of a dierent species of concrete, lighter in specific gravity than the concrete forming body portion and ribs.

3. In a building, a floor comprising oppositely disposed girders, in combination with a plurality of preformed Hoor-slabs, each of said floor-slabs set between and extending from girder to girder', and each Hoor-slab consisting of a mass of hardened concrete embedding a metal reinforcement, the metal of said reinforcement emerging from the y concrete substantially at the ends of the slab to Where the latter obtains support from the girder, and each slab comprising a reinforced body portion, at least two reinforced 15 ribs depending therefrom, and a iat bottom portion connect-ing the bottoms of said ribs, said bottom portion being composed of a different species of' concrete, lighter in specie gravity than the concrete forming 20 body portion and r'ibs, and filling the entire space between ribs and body portion.

In Witness whereof I have hereunto set my hand, this 18th day of February, 1910. CHARLES BENEDICT GRADY. Witnesses: 4

ELIZABETH B. KING, DONALD CAMPBELL.

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