US3354593A

US3354593A - Concrete beamless building construction

Info

Publication number: US3354593A
Application number: US336175A
Authority: US
Inventors: Zukas Simon Ber
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-01-10
Filing date: 1964-01-07
Publication date: 1967-11-28
Anticipated expiration: 1984-11-28
Also published as: NL302877A; BE642388A; GB1045331A

Description

Nov. 28, 1967 s. B. ZUKAS CONCRETE BEAMLESS BUILDING CONSTRUCTION 5 Sheets-Sheet 2 Filed Jan. '7, 1964 Inventor s ayzz'f j u (/6 Nov. 28, 1967 s. B. ZUKAS 3,354,593

CONCRETE BEAMLESS BUILDING CONSTRUCTION Filed Jan. 7, 1964 I 5 Sheets-Sheet 5 1967 s. B. ZUKAS CONCRETE BEAMLESS BUILDING CONSTRUCTION 5 Sheets-Sheet 4 Filed Jan.

I npenlor Nov. 28, 1967 s. B. ZUKAS 3,354,593

CONCRETE BEAMLESS BUILDING CONSTRUCTION Filed Jan. 7, 1964 v 5 Sheets-Sheet 5 M I nvenlor United States Patent Oliice 3 ,354,593 Patented Nov. 28, 1967 3,354,593 CONCRETE BEAMLESS BUILDING CONSTRUCTION Saimon Ber Zukas, Drayton House, Gordon St, London, England Filed Jan. 7, 1964, Ser. No. 336,175 Claims priority, application Great Britain, Jan. 10, 1963, 1,191/63 2 Claims. (Cl. 52--251) This invention relates to a system of construction for beamless structures and aims at simplicity, cheapness where labour costs are high and adaptability to site requirements.

The system in accordance with the invention results in the construction of structures comprising a number of columns devoid of corbels or other lateral protuberances and the space between which is covered by slabs supported by the columns or by neighboring slabs without the aid of beams or the like.

The invention consists, specifically in a system of building construction for beamless structures comprising columns made up of precast concrete sections joined end to end and of precast concrete slabs, the slabs comprising one series (hereinafter called cantilever slabs) supported directly by the column sections and providing cantilever supports for a second series of slabs (hereinafter called bridging slabs) spanning the gaps between adjacent cantilever slabs and framing rectangularly openings each closed by an in-filling slab. The column sections are of uniform cross-section throughout their length except that their upper ends are rebated to provide seatings for the cantilever slabs which are cast with central holes of smaller cross-section than the column sections and are provided with reinforcing bars through the said holes. Each column section is rendered monolithic with a cantilever slab by grouting of the cavity defined by the central hole therein.

The column sections and the slabs can be pre-cast in the workshop and be transported to the building site or can be precast on the site. It is, of course, advantageous to have as small a number of different sizes of column sections and slabs as possible. The dimensions of these depend, naturally, on the height between successive floors of the structure and the spacing of the columns. If the columns have a square pitch, i.e., are disposed at the corners of squares, the slabs can be all of the same size. That, however, is not essential. For example, the cantilever slabs can be made all of the same size, the bridging slabs all of the same dilferent size and the in-filling slabs of the same but still different size. The size of the slabs is governed largely by the lifting apparatus which is availa- Y ble at the building site.

The invention finds its greatest utility in the construction of structures of moderate size in which the spacing of the column is, say, from 12 to 16 feet. In that case, slabs of a uniform size of 6* to 8 feet square can be used, each weighing approximately to 2 tons and presenting no great lifting problem.

The columns can, of course, have a rectangular (nonsquare) pitch. In that case, the cantilever slabs are most usefully made square and the other slabs are suitably elongated.

In the preferred form of the invention, the cantilever slabs are made square with a side length of to 7 of the pitch of the columns.

As the cantilever slabs have to resist a substantial bending moment due to the weight of the slabs and the load borne by the floor, their reinforcement is important and should consist of bars passing in two perpendicular directions through the holes in them.

The columns also have to resist bending, and care must be given to their reinforcement where they pass through the cantilever slabs. In the preferred form of the invention, the joint between column section is reinforced by splice bars located in sleeves provided in the ends of the sections and having ducts leading from the blind ends to the outside which serve as grouting inlets.

The columns being devoid of corbels or the like, the under side of the slabs can provide a completely flat surface extending from column to column. In the preferred form of the invention, the slabs are rebated at their peripheries to provide scarf joints; the floors formed by the slabs having level upper and under faces.

In the course of construction of a building, the cantilever slabs and the columns can be subjected temporarily to uneven loading. This can be avoided, however, by a method of assembling the columns and slabs which consists in lowering each cantilever slab on to the end of a column section, temporaly supporting it at each of its corners, lowering the bridging slabs on to the cantilever slabs while the latter are so supported and lowering the in-filling sla'bs on to the cantilever and bridging slabs, this operation being repeated for the construction of each successive floor. Preferably, the temporary supports are in the form of tie rods formed of two lengths connected together by turn'buckles enabling their overall length to be adjusted.

An example of the practical application of the invention to the construction of a fairly light multifloor structure will now be described in some detail with reference to the accompanying drawings in which:

FIGURE 1 is a sectional plan of part of the building;

FIGURE 2 is a perspective underneath plan of part of the building;

FIGURE 3 shows a joint between a column and a cantilever slab;

FIGURE 4 illustrates diagrammatically a'method of assembling the columns and slabs;

FIGURES 5 and 6 are sections taken respectively on the lines VV and VIVI in FIGURE 1;

FIGURE 7 shows the detail of a joint between two slabs; and

FIGURE 8 illustrates a corner of a floor bay.

As shown in FIGURES 1 and 2, the building has a series of columns 10- which are disposed to form a rectangular grid. In this particular instance, the four columns shown are at the corners of a square. Each column 10 directly supports a cantilever slab A which projects laterally from it in all directions. The gaps, between the cantilever slabs A along the axes of the grid are spanned by a series of bridging slabs B, and the gap framed by a set of four bridging slabs B is closed by an in-filling slab C.

The columns 10 extend throughout the height of the building, floors being provided at desired levels, as shown in FIGURE 3, which illustrates one particular form of joint between a column and a cantilever slab.

The column shown in FIGURE 3 is made up of a series of pre-cast concentrate sections 12. Each section is of uniform cross-section along its length and is provided at the top end with a periperal rebate 13. Each section is also provided at each end with sleeves 14 defining holes for the reception of splice bars 16.

Each cantilever slab A is rectangular in plan square as shown. It is precast in concrete with a central rectangular hole 18 so that the slab can be seated on the column rebate 13. The hole 18 tapers upwards. The slab has a bar reinforcement 20 in the region of its upper surface running in both directions across the hole 18.

In forming the joint shown in FIGURE 3, the slab A is first placed in position on the top of the lower column section 12. Then four splice bars 16 are passed down between the reinforcement bars, are grouted, and the hole 18 filled with concrete. To complete the joint, the upper column length 12 is lowered .on to the splice bars 16 and is grouted in position, grout holes 22 and blow holes 24 being provided for this purpose.

The joint thus formed is substantially monolithic.

To provide extra resistance to the bending moment exerted at the junction between the column and Shah, each splice bar 16 can be provided, as shown, with a steel washer 26 which rests on the top of the slab.

FIGURE 4 illustrates a very convenient method of assembling the slabs to form ,a floor, four phases I, II, III and IV being shown.

At phase I, a lower floor has been completed and a cantilever slab A is being lowered into position on to a column section 12 as explained in connection with FIG- URE 3. Each of the slabs has passing through it, near each of its corners, a tie rod 28 provided with a pair of stops 30, the slabs being formed with holes 31 at their corners as shown in FIGURE 1. The slab A having been set on the column, the tie rods 28 are connected together by turnbuckles 32 as shown at phase II. By adjustment of the turnbuckles, the slab can be accurately levelled and be held firmly in position until the joint between it and the lower column length 12 is completed in a later operation.

The next operation is to lower the bridging slabs B into position, in which they rest on the cantilever slabs, which is illustrated at phase III. During this operation, the cantilever slabs A are held firmly in position by the tie rods 28 in spite of the uneven loading of those slabs. The placing in position of the in-filling slab C, presents no problem and is not illustrated in FIGURE 4.

At phase IV the new floor is completed and has received a new column section 12 so that the construction of a further floor can be stated at phase I. For this purpose, the turnbuckles 32 are removed, the upper tie rods 28 are left hanging by their stops 30, and the lower tie rods 28 are removed and they or another set of tie rods are passed through and left hanging from the new cantilever slab A to be assembled. The procedure from that point onwards is as described in connection with phase I. Thus, the tie rods and turnbuckles are repeatedly used and only a relatively small number of them need be provided. The stops 30, can be removed from the tie rods; or they can be collapsible so that they can, when desired, be passed through the holes in the slabs; or the stops can be permanent and the holes in the slabs so shaped that the rods can be withdrawn by rotating them a half turn.

As has been explained, the cantilever slabs A may be permanently unevenly loaded at those columns which define the outside of the building. That uneven loading can be balanced by special reinforcement in the columns and by the collars 26 provided .on the vertical splice bars as shown in FIGURE 3. In any event, it is advisable to reinforce each column length so that it acts as a vertical cantilever anchored at its base.

The slabs which define the boundaries of the floor can be .of special construction so that they do not project substantially outward beyond the columns on which they are supported. In that case, they would be dimensioned so as to be supported by neighboring cantilever slabs and would not themselves serve as cantilever or supporting slabs.

FIGURES and 6 show respectively the joints between the cantilever slabs A and the bridging slabs B and the joints between the in-filling slabs C and the bridging slabs B. All these joints are scarf joints. The cantilever slabs are similarly rebated in their upper surfaces shown at 36 along their four edges. The bridging slabs are rebated in their lower surfaces as shown at 38 along the two opposite edges which are alongside the cantilever slabs so that the bridging slabs rest on the cantilever slabs. The infilling slabs C are rebated in their lower faces as shown at 40 (FIGURE 6) along their four edges while the bridging slabs are rebated in their upper surfaces as shown at 42 along the edges which are alongside the in-filling slabs so that the in-filling slabs rest on the bridging slabs.

The depth of rebating is such that the floor formed by the slabs has level upper and under surfaces.

The joints between the slabs are finished off as shown in FIGURE 7. As can be seen, a number of rods 46 held in position by stirrups 48 are laid in the gaps between the upper edge of the slabs. These rods extend continuously round the slabs and the gaps are filled in with grout, which may be of quick setting cement so as to render the floor substantially monolithic.

As already mentioned, the slabs at the outer boundaries of the structure built as described above will be unevenly loaded. This state of affairs can be remedied, if desired, as shown in FIGURE 8, by the use of an alternative boundary arrangement in which there are columns 50 which carry trimming slabs E, F, and G, the columns being near the outer edges of those slabs.

This system for building construction can be employed for the ground floor or base from which a building rises, the columns supporting the floor or base then being piles stuck into the ground; this is especially applicable to the smaller types of buildings, such as single or two storey private dwellings and it replaces conventional foundations of the kind involving trench excavation and the placing of footings.

Above the base or raft constructed in this way the building may rise in the same manner as is described above using columns, cantilever slabs, bridging slabs and in-filling slabs.

In some cases it may be desirable to use a base or raft constructed :by a method embodying the invention and to construct the rest of the building in some other manner for example a conventional masonry and timber structure.

I claim:

1. A beamless building floor supported on (a) columns,

(1) each column consisting of precast sections having an upper and a lower end, the upper end of each column section being joined to the lower end of a succeeding one of the column sections, and

(2) each column section being of uniform crosssection throughout the length thereof but being rebated at the upper end;

(b) rectangular cantilever slabs supported directly by the columns and mutually spaced from each other to define gaps therebetween,

(3) each cantilever slab being precast with a central hole of smaller cross-section than the crosssection of the column sections,

.(4) the cantilever slab holes being aligned with the upper ends of the column sections and the rebated upper ends thereof constituting seats for the cantilever slabs, and

(5) said slabs having fiat underfaces extending to said columns;

(c) reinforcing bars in said cantilever slabs and extending across the central holes thereof;

(d) grouting filling the central holes of the cantilever slabs and surrounding the reinforcing bars,

(6) each cantilever slab being rendered monolithic with an associated one of the column sections by said grouting;

(e) rectangular bridging slabs spanning the gaps between adjacent ones of the cantilever slabs, the cantilever slabs providing cantilever support for the bridging slabs, and the bridging slabs defining rectangular openings therebetween; and

( f) rectangular in-filling slabs closing said openings,

(7) all of said slabs forming continuous flat upper and under faces.

2. The beamless building structure of claim 1, wherein the upper ends of said column sections define sleeves, and splice bars are mounted in said sleeves and extend through said central holes of the cantilever slabs, being embedded in said grouting whereby the joint between the upper end of one column section and the lower end of a succeeding one of said column sections is reinforced.

References Cited UNITED STATES PATENTS =Eisen 52260 Borg 52252 Cifll'lilli 10 Murren 522 63 Contini 5273 6 FOREIGN PATENTS 1956 Australia. 1962 Australia.

OTHER REFERENCES FRANK L. ABBOTT, Primary Examiner.

R. A. STENZEL, Assistant Examiner.

Claims

1. A BEAMLESS BUILDING FLOOR SUPPORTED ON (A) COLUMNS, (1) EACH COLUMN CONSISTING OF PRECAST SECTIONS HAVING AN UPPER AND LOWER END, THE UPPER END OF EACH COLUMN SECTIONS BEING JOINED TO THE LOWER END OF A SUCCEEDING ONE OF THE COLUMN SECTIONS, AND (2) EACH COLUMN SECTIONS BEING OF UNIFORM CROSSSECTION THROUGHTOUT THE LENGTH THEREOF BUT BEING REBATED AT THE UPPER END; (B) RECTANGULAR CANTILEVER SLABS SUPPORTED DIRECTLY BY THE COLUMNS AND MUTUALLY SPACED FROM EACH OTHER TO DEFINE GAPS THEREBETWEEN, (3) EACH CANTILEVER SLABS BEING PRECAST WITH A CENTRAL HOLE OF SMALLER CROSS-SECTION THAN THE CROSSSECTION OF THE COLUMN SECTIONS, (4) THE CANTILEVER SLABS HOLES BEING ALIGNED WITH THE UPPER ENDS OF THE COLUMN SECTIONS AND THE REBATED UPPER ENDS THEREOF CONSISTING SEATS FOR THE CANTILEVER SLABS, AND (5) SAID SLAMP HAVING FLAT UNDERFACES EXTENDING TO SAID COLUMNS;