Modular Building Construction Field of the Invention The present invention relates to a system and method of modular building construction. It is particularly adapted for buildings in remote areas such as 5 mining sites, but it is not restricted to this application. Background Art The construction of buildings for remote locations such as mining sites presents some particular difficulties. The sites are usually located in remote areas so that there is no local supply for the required materials. These must be transported for 10 large distances to the sites. As well, there is usually a shortage of skilled labour for such locations and pay and support costs are very high. It is therefore desirable to reduce labour time for construction to a minimum. At the same time, there is a demand for buildings of a higher standard to satisfy the workforce. Finally, buildings erected at such sites often needed at a particular location for 15 only a relatively short time. Traditionally, buildings were abandoned when no longer required. Now, there is a requirement that unwanted buildings be torn down and the site returned to its natural condition. Traditional building materials must be carted away and dumped, often at a distant location. There is a need for an improved construction system and method which at least 20 ameliorates these problems. Disclosure of the Invention Accordingly, the invention resides in a modular building system comprising at least one, lower group of building modules engaged together in side-by-side arrangement to provide the group with a pair of opposed side walls and end walls 25 and adapted to be supported above the ground, each building module being constructed so that it has sufficient strength and rigidity so that it can be dis engagably connected laterally to another building module of the same type to form the group or part of the group, and wherein the group may be supported above the ground only by vertical supports provided proximate side walls of the 30 group.
-2 According to a further aspect, the invention resides in a building module constructed so that it has sufficient strength and rigidity so that it can be connected to another building module of the same type to provide a building 5 group, the group being supportable above the ground only by vertical supports provided proximate external walls of the group. According to a preferred feature of the invention the module comprises a generally cuboid structure defined by steel structural members. According to a preferred feature of the invention, the structure is provided with 10 four pillars by which the module is supported from below and which support the structure. According to a preferred feature of the invention, the module is configured to support another module directly above it by engagement of the corresponding pillars of the two modules. 15 According to a preferred embodiment, each pillar is provided with a spigot at its upper end and a receiving hole in its lower end, the receiving holes of pillars of one module being adapted to receive and locate the spigot of a lower module to thereby locate the upper module accurately and securely. According to a preferred feature of the invention, the structure is braced to 20 provide rigidity. According to a further aspect, the invention resides in a method of construction of a building comprising a plurality of modules, wherein modules are pre-fabricated, and delivered to the construction site and joined together in groups and located into place in groups to thereby create the structure. 25 According to a further aspect, the invention resides in a method of construction of a building comprising a plurality of modules, wherein modules are pre- -3 fabricated, and delivered to the construction site and wherein building sub structure is erected at the site with supporting columns for the modules and temporary beams located for construction and wherein modules are placed upon the temporary beams and joined together in groups and located with respect to 5 the columns after which the temporary beams are removed. The invention will be more fully understood in the light of the following description of one preferred embodiment. Brief Description of the Drawings The description is made with reference to the accompanying drawings, of which: 10 Figure 1 is a lower rear isometric view of a building module according to the embodiment; Figure 2 is a lower front isometric view of the building module of Figure 1, the module shown with the floor and roof purlins removed for clarity; Figure 3 is an upper rear isometric view of the building module according to 15 Figure 2, the module shown with cross-braces removed for clarity; Figure 4 is an elevation a side wall frame of the module of the embodiment; Figure 5 is an elevation of the rear wall frame of the embodiment; Figure 6 is elevation of the front wall frame of the embodiment; Figure 7 is a front sectional view of part of the wall frame of Figure 4; 20 Figure 8 is a plan sectional view of the part of the wall frame of Figure 7; Figure 9 is a side sectional view of the part of the wall frame of Figure 7; -4 Figure 10 is a detailed elevation view of the upper portion of a support post forming a member of the wall of Figure 4; Figure 11 is a detailed elevation view of the lower portion of a support post forming a member of the wall of Figure 4; 5 Figure 12 is a front elevation of a group of six modules of Figure 1 assembled together; Figure 13 is a plan view of a group of three modules of Figure 1 assembled together; Figure 14 is a plan view of an exemplary site identifying the positioning of groups 10 of three modules with respect to the site; and Figure 15 is an isometric view of the site of Figure 14 showing the sub-structure used to support the modules during installation according to a first method. Detailed Description of Preferred Embodiments An embodiment of a modular building system according to the invention is 15 illustrated in Figures 1 to 12. As shown in the drawings, the building system comprises a plurality of unit modules. As is explained in more detail later in the specification, two, three, or potentially more of these modules may be joined together in a lateral or side-by-side group and the group may be supported by as few as four support points only. A group of modules may be above the ground 20 surface so that an area beneath the raised modules may be utilized, for example, for car parking. Figure 1 to 11 show details of a single building unit module 11. Each unit module is constructed of selected steel framing forming a generally cuboid frame structure. As is shown in drawings, the basic structure of the module 11 is 25 formed by two side wall frames 14 and 15, a rear wall frame 16, a front wall frame 17 a floor 18 and a roof 19.
-5 The front wall frame is bounded by two vertical pillars 21 and 22 and by short horizontal beams 31 and 32. The right wall frame is bounded by long horizontal beams 35 and 36 and vertical pillars 21 and 23; the left wall by long horizontal beams 37 and 38 and vertical pillars 22 and 24. The rear wall is bounded by 5 vertical pillars 23 and 24 and short horizontal beams 33 and 34. The floor is bounded by long horizontal beams 36 and 38 and short horizontal beams 32 and 34. The roof is bounded by long horizontal beams 35 and 37 and short horizontal beams 31 and 33. As can be seen in Figure 1, the floor and the roof are provided with a plurality of 10 spaced purlins 71 and 72 respectively mounted between the long horizontal beams and extending the length. In the embodiment, the purlins comprise steel C - channel sections. These provide support for flooring and roofing / ceiling, respectively. They also provide some bracing to the floor and roof frames, resisting twisting or distortion of those frames. The purlins are not shown in the 15 remainder of the drawings to allow other features of the embodiment to be shown more clearly, but it is to be recognized that the purlins are included in any finished structure. The two side wall frames 14 and 15 intersect the rear wall frame 16 and the front wall frame 17 at the primary vertical pillars 21, 22, 23 and 24. As further shown 20 in Figure 4, each side wall comprises an upper horizontal beam and a lower horizontal beam supported by the vertical pillars. Each side further comprises two additional vertical members, substantially equi spaced between the rear vertical pillar and the forward vertical pillar, thereby providing the side with a set of three adjacent rectangles between the rear pillar 25 and the forward vertical pillar. To improve rigidity, each rectangle is braced with at least one steel tie-strap 51 across each diagonal. A fourth rectangle is formed in the side wall in the balcony region by another vertical member at the extremity of the wall. A single, diagonal tie strap 52 is provided across this. As shown in Figure 5, the rear wall 16 of the module, formed by extending a pair 30 of horizontal members between the rear pillars of each wall frame is braced with -6 a single, substantial bracing member 53 disposed across one diagonal of the wall. On the side of the rear wall proximate where the bracing member contacts the upper horizontal beam, a doorway is created in the rear wall by a vertical column 54 between the lower horizontal beam and the brace member. A 5 horizontal lintel 55 extends from this intersection to the neighbouring vertical pillar 23 to complete the door frame. The front wall 17 is also braced. However, a more elaborate bracing structure is provided for this in order to allow for a centrally located and larger access way to the balcony. As shown in Figure 6, this comprises a pair of vertical doorway 10 members 61 symmetrically offset from a centre plane of the module. A horizontal lintel 62 is provided at door height between the two vertical doorway members. Two supporting members 63, 64 extend from the vertical doorway members 61 proximate the height of the lintel 62 to the corners formed between the horizontal members 61, 32 and vertical pillars 21, 22. A final pair of support 15 members 65 extends from the vertical doorway members 61 proximate the height of the lintel 62 to the central region of the upper horizontal member 31 above the lintel 62. It is helpful to note at this point that the forward-most portion of the module is configured as an overhanging balcony extending forward from the front wall. 20 Horizontal members 41, 42, 43 and 44 extend from the front vertical pillars as extensions of the long horizontal beams. The floor of the balcony is extended by horizontal members, the roof and two side walls extend forwardly of the front wall frame to provide the overhanging balcony. However, this region is for utility and does not contribute to the structural strength of the modules, per se. 25 The overall dimensions of the embodiment are approximately 10 metres long from rear wall to front wall, 5 metres wide and 3 metres high ( external measurements). The balcony adds a further 2 metres to the length. Table A below provides a schedule of member sizes that are appropriate for such a module. It is to be noted that these dimensions and member sizes are given 30 solely so that those skilled in the art will have an appreciation of the member -7 strengths relative to the size of the module. Modules of differing sizes to these may be designed which remain within the scope of the invention. TABLE A CODE Items C1 21,22,23,24 150 x150 x9SHS C3 25, 26, 27,28 100 x 100 x 3 SHS C4 29,30 75x 75x3SHS B1 35,36,37,38 150 x100 x5 RHS B2 31,32,33,34 150 x150 x5 SHS ST1 53,64 125 x125 x6 SHS ST2 62,63 75 x 75 x3 SHS BR1 51 11Ox 16 FL DJ1 54,61 100 x 50 x 5 RHS J1 71 U150x 45x4 J2 72 U100 x45x4 5 It can be seen from the above description that the module so formed is of a particularly strong and rigid configuration. It is not required that the wall cladding, floor and roof coverings provide any structural strength to the module. Panels for these can therefore be selected solely for their utility in the particular function, including heat and sound absorption, weather resistance, cost and others 10 characteristics. At the same time it is to be appreciated that it is possible that structural members of material other than construction steel could be used. For example, construction from aluminium members would be possible, and this would be likely to provide a significant savings in the weight of the module. While such a 15 construction would not be economically viable at this time, it certainly would be feasible technically. The inherent strength and rigidity of the modules provide the basis for the special advantage of the embodiment. This is that two or three modules can be held together side-by-side by bolts in the horizontal beams of the side walls and 20 handled as a group. Such a group can be supported above the ground at four -8 points only, at or proximate the vertical pillars of the outer walls of the group. No further support beams are required. The group is supported simply because of the inherent strength and stiffness of each module, when bolted together. Figures 7, 8 and 9 show a typical arrangement for bolting the modules together. 5 Packers are used in association with the bolts to provide a small gap and finely adjust the relative orientation of the modules with respect to each other. As well, several levels of modules may be stacked to provide a multi-level building. Figure 10 is a detailed illustration of a spigot 81 provided at the top of each vertical pillar. Figure 11 shows a corresponding hole provided in the base 10 of the pillar adapted to receive a corresponding spigot. Thus one module may be simply placed upon another module to erect a multi-level group. The modules are held in secure relationship to each other by the spigots without requiring further support. Figure 12 shows an arrangement where six modules are stacked into a group, 15 three modules wide and two modules high supported by four columns only. While two levels are shown, more levels are possible with the module configuration given. Figure 13 shows the outline of the plan view of three modules side by side. Those skilled in the art will recognize that the limit to the number of modules that 20 may be supported side by side without further external beams will depend upon the stress imposed upon the connecting bolts and the frame structure of the modules. The embodiment has been configured so that the maximum number of modules that may be safely joined side-by-side is three. It would be possible to design the module so that a higher number of modules could be supported side 25 by side, and groups of six or even eight modules side-by-side would be possible. However, costs may outweigh the benefits in many cases. It should also be noted that additional levels do not impose any significant load to the support bolts joining modules together or to the frame of the lowest level of modules other than to the vertical force within the vertical pillars in normal 30 circumstances because, the upper groups, themselves, are self-supporting when -9 supported by the vertical pillars of the module below. As each level is equally stiff, they will contribute to resistance to lateral and torsional loads on the building. Of course, the vertical pillars of the modules on the lowest level must withstand the load of the extra levels and are sized for this load. It would be 5 possible to assemble modules with the lowest level modules having the strongest vertical pillars and upper levels having progressively weaker pillars, but it is believed that this would not provide significant savings where only a few levels are provided. In many instances the flexibility of having a single module design on site will outweigh the small savings. Of course the columns must be designed 10 for all likely stresses which will be imposed which will depend upon the maximum number of levels. It is to be appreciated that modules as disclosed herein provide many advantages, especially for use at remote sites or where construction time is critical. Modules may be manufactured in advance at any location of 15 convenience. Manufacturing may be undertaken in a factory - like environment where suitable jigs and the like may be used to ensure assembly to very high tolerances, the like of which are not practicable on site. When final construction is ready, the modules may be taken to site. The modules are of a size that can readily be transported by public roads under normal oversize provisions. Once at 20 site, the building is constructed by joining and placing the module. In a first method of construction, the site level is prepared with the necessary columns to support the modules. Figure 14 is a plan view of an exemplary site showing ground level layout, including car-parking and facilities area. Superimposed on this plan are the outlines of groups of modules as shown in 25 Figure 13. It can be seen from this that by supporting the groups of three modules only from the outer corners of the group, the resulting car parking area is very open and the columns provide only minor obstruction. In the first method of construction, temporary beams are installed for construction as shown in Figure 15. During construction, modules may be placed across these temporary 30 beams individually. Modules are then bolted together in groups of three, or groups of two if such are required. Once all modules are positioned, the - 10 temporary beams are removed, leaving the module groups to be supported by the columns alone. In a second method of construction, the modules are positioned in single-level groups on flat ground proximate the construction site. A crane would then be 5 used to lift groups into position on the columns. Such a method would require that the modules and columns be constructed to a high tolerance level, but if this can be achieved, significant site construction works would be saved. Site construction time will be limited only to the time it takes a crane to pick up and lift the groups into location. Site construction time of only a few days is believed to 10 be practicable for a 72 unit complex. While, the modules have been shown in this specification as just the steel framing, they may indeed be sent to site partly or fully fitted out. This would reduce even further the construction work required on site. Those skilled in the art will recognize that many adaptations may be made to the 15 embodiment which has been described. It is to be appreciated that all such adaptations are to be considered as being within the scope of the invention. Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not 20 the exclusion of any other integer or group of integers.