US2108677A - Precast floor construction - Google Patents

Description

Feb. l5, 1938. H. o. KLOTZ 2,l08,6'577 PREOAST FLOOR CONSTRUCTION Filed March 21, 1936 2 SheeLs-Sheerl l AT GRNEYS.

Feb. l5, 1938. H, o. KLoTz PRECAST FLOOR CONSTRUCTION Filed March 2l, 1956 Y Z'Sheets-Sheef. 2

INVENTOR ATTO R N EY5 Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE 13 Claims.

This invention relates to new and useful improvements in building construction and relates particularly to concrete building construction.

It is an object of the invention to provide a joist and floor construction of concrete or other suitable mastic material which may be precast either at the building site or elsewhere as in a shop, and then easily and quickly assembled on the job under short notice.

Another object of the invention is to provide a light weight low cost re safe roof and iloor construction.

A further object is to provide improved cementitious or molded joist construction adapted to make it possible to quickly and easily install floors and roofs.

Other objects and advantages will become apparent from aI consideration of the following detailed description taken in. connection with the accompanying drawings wherein satisfactory embodiments of the invention are sho-wn. How'- ever it is to be understood that the invention is not limited to the details' shown. but includes all such variations and modiiications as fall within the spirit of the invention and the scope of the appended claims.

`In the drawings:

Fig. l is a perspective view with parts broken away, showing a section of a floor constructed according to the present invention;

Fig. 2 is. a sectional View through the floor at a joist, the View being taken along the line of a wooden sleeper employed;

Fig. 3 is a perspectiveview on a smaller scale showing a portion of a joist prior to its assembly in a roof or floor;

Fig. 4 is a similar view showing a reenforced precast cementitious slab employed;

Fig. 5 is a. view partly in section and partly in elevation showing a portion 4of a joist and the manner in which wooden sleepers are secured in piace;

' Fig. 6 shows a slightly modified arrangement wherein the entire floor is of concrete or mastic material, the wooden, sleepers being omitted and iiat iron tie bars being substituted for the sleepers;

Fig. 7 is a detail perspective view taken. at right angles to Fig. 6 and showing more particularly the manner in, which the iiat iron. tie bars are secured in place;

Fig. 8 is a perspective View showing a carrying girder made upi according to the present invention and supporting the ends of joists;

Fig. 9 is a detail sectional view showing the use of a saddle in the formation of a girder;

Fig. 10 is a sectional view taken substantially along the plane indicated by the line Ill-I0 in Fig. 8;

Fig. 11 is a view similar to Fig. 8 but showing another construction and arrangement of girder and joist; and

Fig. l2 is a sectional view taken substantially along the plane` indicated by the line i2-I2 in Fig. 11.

Referring to the drawings the invention is shown as applied to the formation of a floor although it is to be understood that it may be used in constructing the roof of a building. According to the invention precast cementitious or mastic joist-s and slabs are to be cast or formed either at the building site or at a Shop or the like remote from the scene of the actual erection of a building so that when they reach the building operation they are thoroughly set and cured and there is no making of forms or the like at the point of erection of the building and no waiting during the building operation forl the various parts to set and cure. Therefore the building may be rapidly erected.

In the first form of the invention, that is Figs. 1 through 5 the iioor comprises precast cementitious material such as.' concrete joists I 0 each including a body of the desired length having horizontal shoulders I I at its opposite sides inter'- mediate its height. The lower portion, of each joist is thus thicker than the upper portion thereof and in the lower portion is a reenforcing metal tension bar I2 while in the upper portion of the joist there is. a metal compression bar I3.

Stirrups I4 extend between and connect the bars I2 and I3 at spaced points, and while these stirrupsj are ordinarily spaced four to six inches apart the spacing depends on the load to be carried. Each stirrup I4 comprises a bar or length of metal having its upper portion bent to provide a hook I 5 partially embracing the reenforcing bar I3 and having its lower portion bent par'- tially about the reenforcing bar I2 and extending at the lower side of the same toward a side of the body of the joist.

The stirrups are arranged with the lower horizontally disposed portions I6 of adjacent stirrups extending in opposite directions. With this arrangement the said portions of the stirrups assist in locating the metal reenfor'cing. means in the mold prior to the pouring of the cementitious portion of the joist and retain it properly centered during the pouringy operation, and such stirrup portions also reenforce the side shoulders of the joist. By spot Welding as at I'I, or in any other suitable manner, the stirrups: I4 are secured or tied to the bars I2 and I3.

In their upper edges at suitably spaced locations the joists are provided with notches I8 den signed to accommodate wooden sleepers I9 adapted to have wooden flooring 2E) nailed or otherwise secured thereto. At locations spaced apart as are the notches or recesses I8 cotter pin or hair pin stirrups 2l are embedded in the body oi the joist and such stirrups straddle the bars i2 and I3 (see Fig. 2) and are spot welded to them` as at 22, and the free end portions 23 and 24 of the stirrup arms extend up through the notches I3. It is particularly noted (see Figs. 3 and 5) that one stirrup end portion or arm as for example 23 is somewhat longer than the end 2s. The purpose of'this arrangement will later be set forth.

The wooden sleepers I9 project slightly above the upper edges of the joists, in the neighborhood of a quarter of an inch, and at points spaced apart along their lengths the sleepers are provided with holes 25 to receive the projecting ends of the arms of the hairpin-like stirrups 2I. Joists iii are spaced according to the load to be carried and the holes 25 in the sleepers are spaced to agree with the spacing of the joists. Therefore the parts check on one another and the sleepers are easily located. 'Ihey also properly locate the joists and prevent their being accidentally shifted as the floor slabs 25 are mounted in place. The ends 23 and 24 of the stirrups are of such length as to extend entirely through the sleepers and after the sleepers are in place the said ends are bent over as shown best in Fig. l and the left hand portion of the Figure 5. Since the ends are of different lengths the longer may be struck as with a hammer to bend it over and when the longer is out of the way the other may be bent over in like manner. This saves time and facilitates the bending over operation as it is not necessary to separate the stirrup ends with a tool before bending them over. Also the bent ends of the stirrup arms serve to secure the sleepers in place.

Filling the space between each pair of the joists are precast cementitious slabs 26. They may be of concrete or other mastic material. From Fig. 4 it Will be noted that these slabs may be reenforcedwith metal bars 2'I extending longitudinally and transversely thereof and preferably each slab carries a tongue 28 at one end and a corresponding groove 29 at its other end. The slabs 2E are of such width as to have their side edge portions rest on the side shoulders II` of the joists when the slabs are in place.

Such side edge portions of the slabs are shown as slightly tapered so that the slabs are not as wide at their upper as at their lower edges. This leaves wedge shaped recesses Y3Q between the edges er the slabs and the upper vertical portions of the joists. When the slabs are in place electrical conduits, pipes, or the like may be placed on the slabs and extending below the sleepers, Thereafter grouting 3i may be poured filling the spaces Sii and over the slabs 25 sealing such slabs in place. Also this grouting iiows through holes or openings 32 in the webY portions of the joists forming dowels whereby theV entire structure is interlocked.

Thereafter the floor may be poured with concrete or the like 33 filling the space (see Fig. 1 left hand side) between the joists and ir" desired covering the joists and coming up flush with the upper edges of the sleepers. It is desirable that the slabs 26 as well as the grouting 3l and the ll 33 be of cinder concrete or other light aggregate. After the ll is in place the wooden flooring 2Q may be nailed or otherwise secured to the sleepers i9. It will be appreciated that in the manner and with the parts speciiied a floor may be quickly erected and that in the finished product a substantial and integral structure is Y provided. The grouting and the iill serve to bind all parts in place. Of coiuse the slabs are assembled with the tongue of one in the groove of the next. The sleepers are held against any upward movement by the bent ends of the hairpin stirrups 2l.

Referring now to the modification shown in Figs. 6 and 7a floor having a cementitious top surface is shown. In building this type of iioor after the slabs 2S are in place, instead of the wooden sleepers i9 flat iron tie bars 3-5 are dioposed extending through the notches i5 in the joists and the extending arms 23 and 24 of the stirrups 2l pass through holes in these tie bars and are bent over to secure the tie bars in place. Thereafter ll 35 is poured and it enclosesthe tie bars andlls the notches I8. A iinishing or surface layer 3@ of cement, terrazzo, marble or any composition flooring then completes the job. If desired the ends of the tie bars may be turned up as at 31 to insure a lock between said bars and the surrounding concrete.

Referring to the modification of Figs. 8, 9 and I] a floor including a` carrying girder 38 is shown. Such girder is made up of a pair of the precast joists Ia arranged in parallel relation and spaced a slight distance apart. Saddles 39 (see Fig. 9) are arranged with their lateral arms de in the dowel openings 32 of said joists and with their V-'shaped body portions between such joists and such saddles support a reenforcement comprising a lower rod el and an upper rod l2 are connected through stirrups Ita. The stirrups Ilia are spot welded or otherwise secured to the bars 4I and i12 to form them into a unit which is supported between the two joists Ita by the saddles 39. Y

At the other sides of the joists Itaf and running at `right angles to them are joists Ib` of substantially the same construction as the joists IG of Fig. 1 and including the reenforcing bars I2 and I3 together with the stirrups Il; and 2l the latter serving to tie the wooden sleepers I9 in placeV as will be understood. Hook-like tie members 43 have portions spot welded tothe bars I3 of the joists Iobas at 44 and include portions i5 projecting beyond the ends of the joists. The ends of the joists at the girder are undercut as at #t6 so that the ends of the joists Ilibv rest on the shoulders at the outer sides of the joists VIlm of the girder 38. This is shown in Fig. 8 and there it is noted the tie rod hook portions extend through the notches i 8 in the upper edges of the joists iia so as to be disposed or enter into the space between such joists.

When the parts have been assembled as specified a cementitious material, such for example as concrete, is poured into theY space between the joists Ia thus forming in effect a third joist 41 the position of which is reversed with respectl to the joists lila. Thus it will be seen that the girder 3S is made of three joists of which the outer two are precast while theY intermediate onev is'cast in the iield, and theyrare all connected w forming aunitary girder. TheY mastic material Vpoured to form the intermediate joist of the girder encloses the reenforcing bars M and 42 and the stirrups Ita and also the saddles 39 and the projecting portions l5 of the tie members 53. Additionally the material of the intermediate member il of the girder flows into the dowel openings 32 of the joistsv Illa forming what might be termed dowel pins 48, and such material also fills the notches I8 in the upper edges of the joists Il] and ,lls the spaces between and over 'the joists lilb as at i9 whereby all the parts are securely bound together. It will be seen this arrangement makes a flush ceiling.

In the modication shown in Figs. 1l and l2 a iiooring the same as that shown in Fig. l and including joists It is supported at the upper side of a girder 55 portions of which are precast and a portion of which is cast in the eld. A comparison of Figs. 8 and l1 will show that while the joists are on top of the girder in Fig. 11 they are at the sides of the girder in Fig. 8 so that in the latter iigurethe bottoms of the joists are ush with the bottom of the girder.

The girder 55 comprises similar outer members in the form of precast L-shaped joists 5l and 52 arranged with their toe portions extending toward one another and each including upper and lower reenforcing bars 53 and 54 connected by stirrups 55 to which they are spot welded at 55. The lower portions 5l of the stirrups are arranged horizontally extending toward one another so as to reenforce the toe portions of the 'L-shaped joists.

The joists 5l and 52 are spaced apart a distance depending on the girder to be formed, and arranged between such joists are upper and lower reenforcing bars 58 and 55 connected at suitably spaced points by stirrups @t spot welded or otherwise secured to them. Iron rod tie-s 6I extend horizontally from the joists 5I and 52 into the space between such joists and into any desired relation to the bars 58 and 59 and stirrups Sli. Their ends are preferably turned laterally or curved as shown at tlato anchor them in the beams 5l and 52, they being cast therein when the beams are cast. With these reenforcing members in place a cementitious material such for example as concrete is poured into the space between the joists 5l and 52 and the joists, and such material together with the various reenforcing elements make up the girder 50 which in effect is a unitary structure comprising the outer precast joists 5l and 52 and the inner precast joist-like part E52 which is cast in the field.

It is to be understood that the floor construction of the joists Hl and lub, may be used with steel girders in place of the girders 38 and 50.

From the foregoing it will be seen that the slabs 26 may be very easily installed since they require no cement bed and are interlocking. They may be reenforced with rods as shown or with expanded metal or other reenforcing fabric as desired. While the tension and compression bars and stirrups have been shown and described as kconnected byv spot welding it will be understood that they may be clipped or tied together with wire or connected in any other suitable manner. The joistsmay be used without the precast slabs in which case ribbed metal lath or other self centering material resting on the shoulders of the joists would be used and the entire oor between the joists would be poured during erection of the building. Material other than concrete may be used in making any of the various parts, and the undersides of the joists and slabs are preferably kept smooth to present a neat and finished appearance which can be painted, white washed or the like. Metal lath to receive plaster may be applied to the undersides of the joists by means of wires whereby to form a flat ceiling.

Having thus set forth the nature of my invention, what I claim is:

l. A cementitious joist comprising a body having side shoulders intermediate its height, upper and lower reenforcing bars in and extending longitudinally of said body, upright stirrups at spaced intervals in said body and connecting said bars and having their lower end portions extending toward the sides of the body, and said stirrups arranged with the lower end portions of adjacent stirrups extending in opposite directions whereby said portions assist in locating the stirrups in the mould prior to pouring of the joist and in the complete joist extend under and strengthen the shoulder portions thereof.

2. A joist comprising a cementitious body having a plurality of spaced transverse notches in its upper edge to receive wooden sleepers or tie bars, tension and compression reenforcing bars in the body, hairpin-like stirrups in the body and connected with said bars and having the free end portions of their arms extending into said notches to secure the sleepers or tie bars.

3. A roof or viioor construction comprising spaced supporting joists having side shoulders intermediate their height, stirrups in said joists and extending at the upper sides thereof, wooden sleepers extending across said joists and having spaced holes receiving the extending stirrup porv tions whereby to locate the sleepers and joists relatively, and cementitious means filling the space between said joists.

, 4. A roof or floor construction comprising spaced supporting joists having side shoulders intermediate their height, stirrups in said joists and extending at the upper sides thereof, wooden sleepers extending across said joists and having spaced holes receiving "the 'extending stirrup portions whereby to locate the sleepers and joists relatively, precast cementitious slabs between each pair of said joists and having their edge portions resting on the side shoulders of the joists, and grouting sealing said slabs in place.

5. A' roof or floor construction comprising spaced supporting joists having side shoulders intermediate their height, stirrups in said joists and extending at the upper sides thereof, wooden sleepers extending across said joists and having spaced holes receiving the extending stirrup portions whereby to locate the sleepers and joists relatively, precast cementitious slabs between each pair of said joists and having their edge portions resting on the side shoulders of the joists, and the slabs between a pair of said joists having interlocking connections with one another.

6. A cementitious joist comprising a body having a plurality of spaced transverse notches in its upper edge to receive wooden sleepers or tie bars, tension and compression reenforcin'g bars in the body, hairpin-like stirrups inthe body and connected with said bars and having the free end portions of their arms extending into said notches to secure the sleepers or tie bars, and one of the arms of said stirrups being longer than the other whereby the arms may be bent in opposite directions by striking them with a hammer or the like.

'7. A precast joist comprising an elongated cementitious body, a compression reenforcing bar for the joist in the upper portion thereof and a tension reenforcing bar in the lower portion, a transverse wooden sleeper at the top of the joist, and a hairpin-like stirrup in the body connecting said bars and having the free end portions of lts arms extending at the upper side of said body and through thesleeper for the purpose of se- Y curing the sleeper to the joist.

8. A precast joist comprising an elongated cementitous body, vertically spaced compression and tension reenforcing bars in said joist, a hairpin-like stirrup in the body connecting said bars and having the free end portions of its arms extending at the upper side of said body, said free ends being adapted to be passed through a transversely extending wooden sleeper or tie rod and bent to secure the sleeper or tie rod to the body, and one of the arms of said stirrup being longer than the other whereby the arms may be bent in opposite direction by striking rst the longer and then the other arm.

9. A roof or oor construction comprising spacedY supporting joists having side shoulders intermediate their height, precast cementitious slabs between each pair of joists and having their edge portions resting on the side shoulders of the joists, said joists having spaced transverse openings therethrough above said shoulders, and 4grouting sealing said slabs in place and interlccking the slabs at one side of a joist with those at the other side thereof by flowing into and lling said openings.

10. A roof or floor construction comprising spaced supporting joists having side shoulders intermediate their height, stirrups in said joists and extending at the upper side thereof in the form of a pair of arms, flat iron tie bars extending across said joist and'having holes through which said stirrups pass, said stirrups having their projecting portions bent over and securing the tie bars in place, and cernentitious material filling the spaces between said joists and enclosing said tie bars.

11. A roof or floor construction comprising a girder including a pair of precast cementitious joists each having side shoulders intermediate its height, floor joists at the sides of said girder and having their ends resting on the outer side shoulders of the girder joists, tie bars -extending from said floor joists into the space between the girder jcists, ironY reenforcing bars in said space and extending longitudinally thereof, and a cementitious ller in said space and enclosing said tie and reenforcing bars and securing all the parts together.

l2. A roof or floor construction comprising a girder including a pair of precast cementitious joists each having side shoulders intermediate its height, iloor joists at the sides of said girder and having their ends resting on the outer shoulders of the girder joists, tie bars extending from said floor joists into the space between the girder joists, and a cementitious filler in said space and enclosing said tie bars and securing all the parts together.

13, A precast joist comprising an elongated cementitious body, a compression reenforcing bar for the joist in the upper portion thereof and a tension reenforcing bar in the lower portion, a transversely extending tie bar resting on the joist at the top thereof and projecting laterally therefrom, a hairpin-like stirrup in the body connecting said reenforcing bars and having the free end portions of its arms extending at the upper side of said body and bent over the tie bar for the purpose of securing the tie bar to the joist.

HENRY O. KLOTZ.

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