Method Of Building Construction

Abstract

A circular (or any other geometric shape) concrete floor slab is first formed with a central circular cavity extending down to a foundation. A reinforced concrete roof structure is constructed on top of the floor slab with the aid of a vertical gin pole projecting up from the cavity and a smoothing and shaping screed that rotates around the pole. The roof structure consists of a radially extending perimeter portion that merges smoothly and monolithically into a centrally located, upwardly extending hollow column portion. When completed, the roof-column structure is raised from the slab and inverted. The monolithic column portion is then inserted into the cavity to rest on the foundation. In an alternative construction the roof structure is not poured monolithically with the column portion, but is made in otherwise the same manner around a prefabricated column already mounted in the cavity. The roof structure is finally raised upwardly along this column and secured thereto without inversion.

Description

This invention relates to an improved method of building construction.

More particularly, the method according to the present invention is designed to simplify the constructional operations to be carried out, enabling the erection of buildings with a minimum of skilled labor.

Various manners in which the invention may be carried into practice are illustrated diagrammatically in the accompanying drawings. It is to be understood that these illustrations and the accompanying description are provided by way of example only and not by way of limitation of the broad scope of the present invention, which latter is defined in the appended claims.

In the drawings:

FIG. 1 is a vertical cross-section of a building site at an initial stage;

FIG. 2 is a partly cut-away plan view of FIG. 1;

FIG. 3 is a section on the line III--III in FIG. 2;

FIG. 4 is a perspective view of the lay out shown in FIG. 2;

FIG. 5 is a view similar to FIG. 4 at a latter stage in the operation and showing a straight screed in use in the formation of a floor slab and the levelling of such slab;

FIG. 6 is a fragmentary vertical section of a portion of FIG. 5;

FIG. 7 is a view generally similar to FIG. 6, but showing the assembly at a later stage in the operation;

FIG. 8 is a vertical central section of the assembly of FIG. 5, showing also the addition of further parts;

FIG. 9 is a plan view of the assembly at a still later stage;

FIG. 10 is a section on the line X--X in FIG. 9;

FIG. 11 is an enlarged fragmentary view of a portion of FIG. 9 showing more detail;

FIG. 12 is a view similar to FIG. 10, but also showing a curved screed in position for forming a roof section;

FIG. 13 is a section on the line XIII--XIII in FIG. 12;

FIG. 14 is a smaller scale, side elevation view showing the operation of the curved screed in smoothing poured concrete;

FIG. 15 is a view similar to FIG. 14, but showing a further stage in the operation;

FIG. 16 is another view similar to FIG. 15 at yet a further stage;

FIG. 17 is an elevation view showing a manner of lifting the roof section;

FIG. 18 is a further elevation view showing the roof section inverted and placed in position in a cavity in the floor slab;

FIG. 19 is a vertical central section of an alternative construction; and

FIG. 20 is a section on the line XX--XX in FIG. 19.

FIG. 1 shows a buiding site on which a layer of fine gravel 10 has been placed on the ground 11 to form a bed for a floor slab. The site has been shown to be circular in plan, but, as explained more fully below, square or other shapes can be employed.

The perimeter of the site is defined by a circular form 12 which projects above the upper surface of the gravel bed 10. Centrally of the site there is formed a cylindrical cavity 13 the sides of which are maintained by a metal retaining wall 14. Upper edges 15 of the wall 14 serve to define the inner perimeter of the shallow cavity defined by the perimeter form 12.

A mass of concrete 16 is poured into the bottom of the cavity 13 to form a foundation. The size and shape of the foundation needed will depend upon the firmness of the terrain. If necessary, additional earth may be excavated and a larger body of concrete employed. This has been diagrammatically illustrated at 16', and it will be apparent that the shape and other characteristics of the foundation can vary widely depending upon the particular requirements.

A central cylindrical hole is formed in the foundation 16 and into this hole there is inserted a tube 17 that is adapted subsequently to receive a gin pole 18 (FIG. 4). If preferred, the parts 17 and 18 can form a single pole that extends directly down into the hole in the foundation 16. The upper end of the tube 17 is braced with a disc 17a or any other convenient form of bracing, to ensure the verticality of the parts 17 and 18. Guy wires (not shown) may extend from the top of the pole 18 to the ground to ensure its verticality, and serve as supports for a temporary tent like structure (not shown) protecting the work area from the elements like rain, snow, sun, etc.

As shown in FIGS. 2 to 4, radial conduits 20 are then laid on the bed 10. After the formation of the floor slab 21, in which these conduits become embedded, they can subsequently serve for the conveyance of utilities, e.g., electric power, from the central area outwardly to other parts of the construction. See, for example, the access hole 20a (FIG. 6) that can later be formed in the floor slab 21.

With the basic site thus prepared, concrete is poured into the shallow annular cavity defined by the form 12 and edges 15 to form the floor slab 21 (FIGS. 5 and 6). Before it sets, the concrete is shaped and smoothed by means of a straight lower member of a screed 22 which has a central bushing 23 rotatable around the gin pole 18, the outer end 24 of the screed resting on the circular form 12.

Once the floor slab 21 has hardened, the form 12 is raised, as shown in FIG. 7, to define the perimeter of a new annular cavity in which the roof assembly will be formed. Further preparations for the formation of the roof assembly are shown in FIG. 8 which illustrates the positioning of a polyethylene sheet 30 or any other type of bond break on the upper surface of the floor slab 21 to prevent the concrete of the roof assembly joining with that of the floor slab. A cover 31 has also been placed over the top of the central cavity 13 in order to close it against the intrusion of the concrete that will subsequently be poured. A cylindrical form 32 has been mounted on the member 31, to surround the pole 18, appropriate bracing discs 33 or like means being provided to ensure that the form 32 and the pole 18 remain coaxial with each other.

Using the floor slab as a base, the next stage in the operation is to mount the reinforcing steel framework that will be embedded in the roof assembly, for which purpose attention is now directed to FIGS. 9 to 11. This framework may take many and varied forms, depending upon the loads for which the building under construction is designed. The particular pattern of steel shown in these figures is thus illustrated solely by way of example of one possible pattern with which the roof assembly may be reinforced.

The steel reinforcing rods shown in FIGS. 9 to 11 consist of a series of radially oriented rods 34 connected to circumferentially extending rods 35 that are in turn supported on small concrete blocks 36 resting on the polyethylene sheet 30 that overlies the floor slab 21. At their inner ends the rods 34 are bent vertically upwardly and connected to further vertically extending rods 37 that project upwardly around the form 32 while being spaced therefrom. Circumferential rods 38 or, if preferred, a continuous helical rod, complete the reinforcing surrounding the form 32. Bracing rods 39 extend radially and downwardly from connections at 40 to the vertical rods 37 to connections at 41 to the main radio rods 34. Further bracing for these rods 39 may be provided by intermediate rods 42. Plates 43 with fixing holes and associated anchoring rods 44 may be located in this pattern of reinforcement to facilitate subsequent lifting of the roof assembly in the manner that will be explained below.

Once this framework of reinforcement has been put in place, a curved screed 50 (FIG. 12) is mounted by means of a bushing member 51 to rotate around the pole 18. As best seen in FIG. 13, the screed 50 is triangular in cross-section, having a lower longitudinal member 52 which serves for smoothing and shaping the concrete, and two upper longitudinal members 53 and 54. Bars 55 extend transversely between the longitudinal members. In side view the screed 50 extends radially inwardly in a gentle curve from a slightly upwardly extending outer portion 56 that rides on the form 12 to a truly vertical portion 57 that extends upwardly around the form 32 spaced outwardly from the reinforcing framework. As well as serving to shape the concrete surface, the screed 50 can be used as a ladder during the subsequent phases of the operation shown in FIGS. 14 and 15.

FIG. 14 demonstrates the manner in which a body of low slump concrete 60 which has been poured onto the assembly can be smoothed into the curved shape shown, by the member 52, upon rotation of the screed 50 around the pole 18. To complete the construction, a further cylindrical form 61 (FIG. 15) is placed in spaced relation around the outside of the reinforcing rods that surround the form 32 and concrete is poured between the forms 32 and 61, as demonstrated in FIG. 15. It will be at this time that it is especially convenient to use the screed 50 as a ladder for the workmen who will be directing the concrete betwen the forms and using conventional vibrators for compacting the same. It will be noted that FIG. 15 shows small cavities 62 that have been formed in the concrete to allow access to the lifting plates 43. Similar cavities will be formed on the underside of the roof structure.

The product of these operations, once the concrete has hardened, is illustrated in FIGS. 16 to 18, and consists of a roof assembly shown generally at 63 and consisting of a circular, generally disc-like portion 64 that expands in thickness as it extends radially inwardly from a relatively thin perimeter 64', this portion 64 ultimately merging smoothly and monolithically into a hollow column portion 65. After removal of the various forms and the gin pole 18, roof assembly 63 is lifted off the polyethylene sheet 30 on the floor slab 21 by any convenient means, such as by attaching a crane hoist assembly 66 to the plates 43 (FIG. 17). The crane will be manoevered to invert the roof assembly 63 and to connect the hoist to the holes in the plates 43 on what was previously the underside of the roof assembly. This assembly is then lowered so that its column portion 65 enters the cavity 13 defined within the cylindrical member 14 until it rests on the foundation 16, parts such as the cover 31, the tube 17 and the bracing disc 17a having been removed by this time.

An alternative method of construction is shown in FIGS. 19 and 20. The floor slab 21 is formed exactly as before. However, before the roof assembly, now designated 63a, is formed, there is first inserted into the central cavity 13 to rest on the foundation 16 a preformed, reinforced hollow concrete column 67. The roof assembly 63a is formed around the column 67 in basically the same manner as already described, i.e., employing the gin pole 18 and screed 50 and an appropriate embedded reinforcement framework. But in this case the roof assembly is formed without a column portion. After formation, the roof assembly 63a is raised from the floor slab 21 but not inverted. It is moved up along the column 67 and fixed in place at a suitable elevation thereon. The method of securing the roof assembly to the column may take any convenient form. In the example shown, concrete keys 68 extend through holes in the column 67 and engage the undersurface of the roof assembly 63a. A cap 69 can be placed on top of the column 67.

The external wall structure of the building (not shown) will then be erected. This structure will normally consist of a series of panels each mounted to extend between the perimeter of the floor slab 21 and the coresponding perimeter portion 64' of the roof assembly 63 or 63a. An important advantage of the present construction resides in the fact that the wall panels are not required to support any of the weight of the roof, the latter being entirely cantilevered from the central column. The hollow nature of this column facilitates obtaining access for utilities to various parts of the building and the establishment of communication between the interior of the column and the conduits 20 leading to the perimeter portions of the floor slab.

In a case where it is desired to make the floor plan square, the perimeter form 12 will be square. The pattern of reinforcement for the roof assembly will be correspondingly modified. Each screed will have to be long enough to reach to the corners of the square, but otherwise they will operate in essentially the same manner as described above.

The fact that the roof structure is supported by its column portion 65, or by the independent column 67, directly on the foundation 16, independently of the floor slab 21, provides a form of construction that has more resistance to destruction by earthquake than a traditional construction consisting essentially of four (or more) vertical roof supporting members spaced apart from each other.

However, in the case where seismic considerations are not pertinent, the foundation 16 can be joined to the floor 21 by means of reinforcing steel bars having a shape similar to an elongated letter Z embedded in concrete, so as to cause the floor slab 21 to act as an integral part of the foundation supporting the column for the roof assembly.

Claims

I claim:

1. A method of building construction comprising

a. forming a flat, horizontal, concrete floor slab on the ground with a centrally located, vertically extending, cylindrical cavity projecting downwardly through the slab to a foundation,

b. erecting a pole extending upwardly from said cavity coaxial therewith, said pole difining a vertical axis,

c. erecting framework of reinforcement on said slab, said reinforcement including a portion extending upwardly around said pole,

d. pouring and retaining concrete on said slab to embed said reinforcement and form a roof structure having a radially extending perimeter portion merging into a centrally located, vertically upwardly extending hollow column portion surrounding said pole,

e. mounting a screed on said pole to rotate around said vertical axis, said screed including a member having a portion extending vertically downwardly around the pole and then curving smoothly outwardly to a radially extending portion for smoothing and shaping the surface of the concrete of said roof structure while still soft,

f. after hardening of the concrete forming the roof structure, raising the roof structure from the slab, inverting the roof structure and lowering the column portion thereof into said cavity to rest on the foundation.

2. A method according to claim 1, including embedding at least one conduit in said floor slab extending from said cavity towards a perimeter of the slab.

3. A method according to claim 1, wherein said floor slab is formed by pouring and retaining concrete between inner and outer perimeter forms and by mounting a further screed on said pole to rotate around said vertical axis, said screed including a horizontal member for smoothing and shaping the surface of the concrete of the floor slab.