GB2147635A - Foundation for suspended floors - Google Patents

Abstract

Method for constructing a suspended floor structure for a building includes drilling a pattern of holes (1) in the terrain, positioning a temporary, load supporting and jacking structure (2, 3) over the holes (1) to support a plurality of load supporting beams (4) which are to form part of the suspended floor structure, fixing downwardly extending support columns (5) to the supporting beams (4) with the columns (5) located in the holes (1), levelling the beams (4) using the temporary supporting and jacking structure (2, 3), pouring concrete into the holes (1) to fix the columns (5) in the holes (1) and then fixing decking (6) to the beams (4). Lintels (10) attached to the columns 5 are used to support brick walls built on the lintels, after the temporary structure (2, 3) has been removed in order to enclose the floor structure. <IMAGE>

Description

SPECIFICATION Improvements in Building Techniques The present invention relates in general to improvements in building techniques and more particularly, but not exclusively, to an improved method for the provision of a stable foundation structure (preferably elevated) for supporting a building or the like. The invention also relates to an improved flooring or foundation structure and to improved elements or components for use in such a structure and in the method of construction thereof.

The method and structure (equipment) in accordance with the present invention is particularly designed for use on hilly or uneven sites. It should be understood, however, that the method and equipment in accordance with the invention could equally well be employed on any site, hilly, sloping, uneven, flat, unstable, rocky or otherwise. For purposes of explanation, however, throughout the ensuing description reference will be made to the utilization of the subject method or building technique on a site that is hilly or uneven, or perhaps more correctly sloping.

Nowadays it has become a common practice to employ a concrete slab of a predetermined size as the foundation upon which a building orthe like structure is to be subsequently erected. Such a now traditional slab-on-ground technique has been found to require for its effectiveness a substantially level site. In order to achieve such a substantially level site, especially in hilly, sloping or undulating terrain, it has generally been found necessary to employ heavy earthmoving machinery, for purposes perhaps of excavating and levelling an undulating site, or alternatively back-filling such a site. Such a requirement for the use of heavy earthmoving machinery and the like equipment gives rise to a number of practical disadvantages.

First of all, such equipment is expensive both to secure and operate. Secondly such machinery or equipment has been found to be in itself responsible for damage not only to the site being worked, but also to surrounding areas. By way of explanation, earth moving equipment of the type under consideration is, by its very nature, rather substantial in size. The continued passage of such heavy equipment over any site in the long term can give rise to problems insofar as drainage of such a site itself is concerned. Furthermore, and if the site being worked happens to be in an otherwise established or built-up area, damage can be caused to other sites (albeit inadvertently).Indeed, such equipment may well cause such damage to the environment as to ultimately call for or require the reestablishment of vegetation, of expensive paths, pavings etc. cracked by the very weight of the equipment, etc. Furthermore, the usage of excavating or earthmoving equipment invariably gives rise to a need for either the removal from the building site of large volumes of unwanted material, or alternatively the delivery to the site of back-filling material.

The traditional building techniques, such as for example the slab-on-ground technique as previously referred to, can also suffer because of the weather. By way of example, during wet or wintry weather excavated sites or sites to be excavated can very often become to all intents and purposes physically unworkable, thereby leading in turn to annoying and expensive delays in actual construction. By way of further example, if after heavy rain previously erected trenches or the like have to be re-dug or re-excavated, with a resultant widening or deepening thereof, additional costs by way of filling can be incurred.

The present invention seeks to overcome the problems associated with the prior art building techniques by providing what might be termed a suspended floor system or structure which involves in its construction minimal interference with a building site, thereby leaving the site and its inherent natural drainage and vegetation substantially intact.

In accordance with one aspect of the present invention, therefore, there is provided an improved technique or method for use in the construction of a suspended floor structure for buildings and the like, said method including the steps of: (i) forming a plurality of spaced-apart holes in a predetermined pattern, over a proposed building site; (ii) positioning a temporary load-supporting structure over said pattern of formed holes in a predetermined manner-(in accord with the intended floor plan for the building), said structure including at least a longitudinal array of load-supporting beams (preferably of steel) of any desired crosssection; (iii) affixing a plurality of downwardly extending support or column members to said longitudinal array of load-supporting beams, said columns being adapted to be located in said formed holes;; (iv) adjusting the location of said temporary structure and associated beams and columns whereby to provide a substantially level or horizontal structure; (v) fixing said column members in said holes, preferably per medium of concrete, cement or the like material poured thereinto; and (vi) affixing a suitable decking material to the structure whereby to provide a substantially level, stable, suspended floor support structure or configuration for subsequent building.

In accordance with a further aspect of the present invention there is provided an improved cleat for use in connecting said support or column members to said load-supporting beams, said cleat including a connection plate portion or member having a base portion dependent therefrom, said base portion including at least one downwardly extending protrusion or spigot.

In accordance with yet another aspect of the invention there is provided a building clamp as illustrated.

In order that the invention may be more clearly understood and put into practical effect there shall now be described in detail a preferred method of construction or building technique in accordance with the invention. The ensuing description is given by way of non-limitative examples only and is with reference to the accompanying drawings, wherein:: Figure lisa top plan view of a building site having a floor system in accordance with the present invention in a first stage of construction thereon; Figure 2 is a view taken in the direction of the arrow 2 in Figure 1; Figure 3 is an exploded perspective view of part of a floor system in accordance with the present invention, including a support beam, vertically disposed column and layer of decking material, in a later stage of construction to that of Figure 1; Figure 4 is a view taken along the line 4-4 of Figure 1; Figure 5 is a view taken along the line 55 of Figure 1; and Figure 6 is a perspective view of a construction (house) incorporating the floor system in accordance with the present invention.

The first step in the preferred method or building technique in accordance with the present invention involves the drilling of a number of holes 1 on a building site in a prearranged or predetermined pattern. In this regard, and from a practical point of view, it has been found that a drilled hole constitutes a very stable excavation and will be less susceptible to collapse than will a dug hole or a trench (procedures employed in the prior art). These holes may be located over the building site to suit floor plan requirements. The spacing between holes and the relative location thereof can be altered as desired.

It should be understood that, strictly speaking, no other preliminary work will be required on or to the proposed construction site. Preferably, however, it would be desirable to clear any unwanted vegetation, rocks, etc.

Once the aforementioned holes 1 are drilled on the proposed site, a structure made up of what might be termed temporary support beams 2 is adapted to be located on that site and are fixed and levelled by any suitable means, as for example by means of an appropriate number of jacks 3 located around the periphery and internally of the structure.

Once in position, the structure of temporary beams 2 can be seen to provide a substantially level configuration. The method in accordance with the present invention can therefore be seen to remove altogether the need for any preliminary levelling, back-filling etc. of the building site in order to provide a level surface for subsequent construction of a building on that site.

A floor support structure of the desired size, shape etc. can either be constructed on site or prefabricated off-site and then be laid out on the structure oftemporary beams previously provided.

Such a floor support structure includes a framework or load-supporting or load-bearing beams 4 (of a predetermined size, strength etc. to suit engineering and strength requirements), that framework having depending therefrom a plurality of downwardly extending columns 5 of any suitable material, as for example steel, the downwardly extending columns 5 being located on the framework in a predetermined pattern, there being a number of such columns equivalent to the number of holes 1 previously drilled on the building site.

In practice it has been found that, so long as the building under construction, or more correctly the proposed floor thereof, is no more than three metres above ground level, then a structure consisting of a plurality of longitudinally extending temporary beams 2 is necessary and sufficient (with no transverse or lateral bracing members being required). However, and again in practical terms when the proposed floor level is in excess of three metres above ground level, it is recommended that some form of lateral bracing be employed. It should be understood, however, that such lateral bracing does not constitute a necessary and essential feature of the subject invention.

When the floor support structure is properly located on the system of temporary beams, the columns 5 depending therefrom will be located in the previously drilled holes 1. When in such a position the floor support structure may be readily squared and final levels taken to ensure that an effectively horizontal surface is provided for any subsequent structure to be built thereon. Once the composite structure is deemed level, concrete or the like material may be poured into the holes formed on site such that the downwardly extending columns 5 are ultimately embedded therein. When the thus poured concrete has set, then the structure of temporary beams or supports 2 may be removed.

The result will be a substantially level structure, suspended above ground level to a prearranged height. In accordance with known building techniques a layer 6 of so-called Bondeck or other equivalent decking material of any suitable type, as for example consisting of lengths of sheet steel or the like, may be located on the floor support structure in any known manner, as for example by bolting. In an especially preferred embodiment, as illustrated, a plurality of panels of pre-cast steel may be employed, with adjacent panels to be connected in any known manner to the beams 4, as for example by puddle welding, gun nailing, screwing or bolting. The temporary support structure and associated floor support structure then constitute an enclosure and, if required, a concrete sheet or slab may then be formed thereon in any suitable manner, again in accordance with known building techniques. Alternatively, a system of floor boards or the like or indeed any suitable flooring material may be employed.

The method and apparatus in accordance with the present invention preferably and primarily employs galvanized steel cold-formed sections as the major load-bearing and structural components of both the system of temporary beams and the prefabricated floor support structure. Load is transferred to ground by the columns 5 set in concrete, the columns 5 being either substantially circular or substantially parallelepipedal in cross-section in accordance with known techniques.

In order to allow for connection or interconnection of the beams and downwardly depending columns making up, with the temporary support members, the so-called floor support structure, in accordance with a further aspect of the present invention there is provided a special and particular form of so-called cleat 7. The accompanying representations illustrate preferred embodiments of a cleat 7 in accordance with the present invention. In general terms, when viewed in side elevation, a cleat 7 in accordance with the invention is of a substantially inverted T-shape, comprising a connection plate 8 (preferably cast) having either a circular or a parallelepipedal base 9 depending therefrom, the actual shape of that base 9 being governed by the cross-sectional shape of the column 5.The base 9 has one or more spigots (not shown) extending therefrom whereby to allow for accommodation of at least two different cross-sectional sizes of columns. In other words a column of one size (cross-section) is adapted to fit internally of the depending spigot, or alternatively a larger-sized column may be located externally of that spigot. The cleat may be connected to a beam of the prefabricated floor structure in any suitable manner, as for example by having the connection plate portion bolted to that beam (see Figure 2). In an especially preferred embodiment two pairs of horizontally aligned apertures are provided at spaced-apart positions on the connection plate of the cleat 7, such an arrangement allowing for vertical alignment of a column 5 along the axis of an associated loadbearing beam 4.

Once the floor support structure is fixed in the desired position on the site, as for example by setting of the poured concrete in the previouslydrilled holes, and the temporary beam structure is removed, the next step in the building of a house or the like involves the laying of bricks. In orderto assist in bricklaying lintels 10 of any known type are adapted to be fastened to the downwardlydepending columns 5 in any suitable manner, and more particularly through use of a suitable clamping means. In accordance with known techniques such lintels 10 may be stepped in courses around the overall structure to follow the terrain and changes in floor levels as a result of accurate positioning of such clamps on the downwardly-depending columns (as desired).The provision of such clamped lintels 10 etc. facilitates the task of a bricklayer in setting and levelling an initial course of bricks, and furthermore effectively eliminates the possibility of errors occurring therein.

The clamp as referred to in the preceding paragraph may also be employed for other purposes, as for example the attachment of timber beams to the columns or the floor structure, as would be required in the instance of a timber decking, verandah or the like required to be disposed around the perimeter of a house or other structure.

The technique or method of construction in accordance with the present invention, and the elements utilised therein, can be seen to be responsible for a number of advantages, as explained in detail hereinafter.

One of the major advantages of the technique in accordance with the present invention resides in the utilization of a floor support structure which is adapted for easy positioning on a previouslyprepared (or even unprepared) site. The utilization of such structures, prefabricated off site or built or erected on site serves to minimise the amount of on-site preparation and labour, not to mention tooling. In a practical sense, once the columns 5 with associated temporary beam structure are fixed in position on site and the floor support structure located thereon, then effectively the only tool required will be a spanner or the like. This reduction in on-site labour can be seen to be especially important in cold or wet climes.The lack of a need for any sophisticated equipment, as for example electrically-operated tools, reduces the possibility of accidents on building sites, it being understood that the use of electrical tools with depending wiring in wet conditions is somewhat dangerous to say the least.

The utilization of preferably prefabricated structures also is responsible for minimisation of wastage of material on site. Indeed only material which will ultimately be used on site need be transported to that site, thereby reducing transport costs (delivery and removal).

As stated earlier, a further advantage associated with the method or technique in accordance with the present invention is that minimal disturbance of the site prior to construction is necessary. Indeed, and in contrast with the prior art techniques, no excavation or back-filling is required in accordance with the method of the present invention.

In terms of cost, a substantial reduction is achieved with the method in accordance with the present invention by reason of the need, first of all, for utilization of a much reduced quantity of concrete or the like material. Indeed when compared to conventional techniques, utilizing a concrete slab extending over the entire site for building, the method in accordance with the present invention, which requires concrete only in certain localised areas-around the downwardly depending columns 5 in the drilled holes 1-has been found ta give rise to a reduction in the volume of concrete of the order of perhaps 50%. This need for utilization of concrete only in localised areas in turn means that the actual volume of concrete employed is controllable, a fact which allows for construction to go ahead at a fixed price. This is in marked contrast to prior techniques, wherein the volume of materials, such as concrete, to be employed was largely uncontrollable, thereby giving rise to substantial fluctuation in price for any given structure, dependant on such variables as soil conditions, etc.

The holes 1 drilled for receiving the columns 5 in accordance with the method of the present invention are in fact drilled to a depth below what might be termed unstable soil conditions. In other words, the columns 5 are more or less sited on bedrock. This factor alone can be seen to give rise to a substantial reduction in the likelihood of any subsequent movement of a completed building or structure. With the prior art techniques, even when a substantial solid concrete slab was employed a certain degree of movement could take place dependent upon changes in, for example, the moisture content of the surrounding soil. Any movement of the concrete slab in the prior art gave rise to subsequent cracking of brickwork, plaster etc.

The arrangement in accordance with the present invention, set as it is substantially in bedrock, is not susceptible to such cracking orthe like.

It should be understood that, whilst the method in accordance with the present invention is especially suited for use with the building of new homes, the method or technique can in fact be adapted to suit any home design. In a practical sense, however, savings in time, material, labour and expense can be expected to be more significant if the flooring system as produced by the subject method is incorporated in any plans or the like right from the outset. Aflooring system as produced by the present method has been found to be especially successful in the construction of external decking, car-ports and/or recreation areas on existing homes.

Again in a practical sense, and in contrast to conventional building techniques involving the utilization of a concrete slab, the flooring system in accordance with the present invention has been found to provide up to double the usable floor or living space, depending of course on the building site itself, over the same ground area and with substantial savings in construction time, labour, materials and accordingly money.

In an especially preferred embodiment the method of the present invention may be used in conjunction with what may best be described as a "kit", constituting all the components required for construction of a suspended flooring system in accordance with the invention. Indeed all material needed for construction, including load-supporting beams, columns, decking material, edging material and reinforcing fabric or material, may be supplied on site to suit the specific requirements of a builder (together of course with appropriate instructions for the correct utilization thereof). The flooring system may then be installed either by the builder, or by licensed sub-contractors, thereby ensuring speedy erection and structural reliabiiity.

Once the decking material 6 is in place, provision can be made for ultimate connection to or of services, as for example, power, gas, plumbing, heating etc. In an especially preferred embodiment, not illustrated, those areas designed for service penetrations may be boxed out. In an alternative arrangement, suitable penetrations to accommodate service material may be drilled out in the correct position once the concrete slab formed on the decking material has set or cured to the desired level. With the technique in accordance with the present invention cables, pipes and other service ducting etc. are adapted to be supported beneath the decking material 6, thereby to be effectively proof against the possible ravages of moisture and within easy reach and access for repair, maintenance, replacement etc.

The method or building technique in accordance with the present invention, by reason of its very simplicity, will be seen to be responsible for substantial reductions in labour time, in terms of site preparation (or rather lack of such preparation), actual construction time, etc. Reduction in labour time in turn gives rise to substantial reduction in overall costs, an important consideration nowadays when the building industry is at somewhat of a low ebb.

Finally, it is to be understood that the aforegoing description refers merely to preferred embodiments of the present invention, and that variations and modifications are possible without departing from the spirit and scope of the invention, the ambit of which is to be determined from the ensuing claims.

Claims (10)

1. A method for use in the construction of a suspended floor structure for buildings and the like, said method including the steps of: (a) forming a plurality of spaced-apart holes, in a predetermined pattern, over a proposed building site; (b) positioning a temporary load-supporting structure or sub-frame over said pattern of holes in a predetermined manner, said structure including at least a longitudinally disposed array of loadsupporting beams of any desired cross-section; (c) affixing a plurality of downwardly-extending support or column members to said longitudinallydisposed array of load-supporting beams, said columns being adapted to be located in said fomed holes; (d) adjusting the location of said temporary subframe and associated beams and columns whereby to provide a substantially level or horizontal structure; (e) fixing said column members in said holes; and (f) affixing a suitable decking material to said composite structure whereby to provide a substantially level, stable, suspended floor support structure or configuration for subsequent building thereon.

2. The method as claimed in claim 1, wherein said holes are formed on said building site by drilling.

3. The method as claimed in claim 2, including the further step of attaching lintels to said downwardlyextending column members whereby to facilitate the laying of courses of brickwork or the like.

4. The method as claimed in claim 3, including the further step of attaching a suitable edge-forming material to said temporary sub-frame, said edgeforming material, in conjunction with said decking material, forming an enclosure for concrete or the like material.

5. The method as claimed in claim 4, including the further step of pouring concrete or the like material into the enclosure formed by said decking material, thereby to provide a floor slab for said building.

6. The method as claimed in claim 5, including the further step of boxing out areas on said decking for the installation or connection of services, prior to said step of pouring concrete or the like material into said enclosure by said decking material.

7. The method as claimed in claim 6, wherein said longitudinally-disposed load-supporting beams are constructed of galvanized steel cold-formed sections, and said decking is constructed of Bondeck.

8. The method as claimed in claim 7, including the further step of providing reinforcement material on or in conjunction with said decking.

9. A suspended floor structure, when produced by the method as claimed in claim 1, substantially as described herein with reference to the accompanying drawings.

10. A method for use in the construction of a suspended floor system or structure for buildings and the like, substantially as described herein with reference to the accompanying drawings.