GB2121851A

GB2121851A - Monocoque building method

Info

Publication number: GB2121851A
Application number: GB08315458A
Authority: GB
Inventors: Ray Morley Wolfenden
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-06-08
Filing date: 1983-06-06
Publication date: 1984-01-04
Also published as: GB8315458D0; GB2121851B

Abstract

A building has a continuous shell which does not have a separate skeletal framework transmitting load directly to the foundations, a plurality of elongate strips of material 10 each of similar "paraboloid" or "polygonal" profile are joined together side by side. The strips 10 may be subjected to gradual bending "in-situ" so as to stress the material and held under tension by cables connecting the free end and/or by clamping the free ends to the foundation. Alternatively the strips 10 may be to some extent precurved. Each strip may be formed from an inner and outer membrane 18, 13 bonded together by a layer of thermal insulating material 20. <IMAGE>

Description

SPECIFICATION Monocoque building system This invention relates to a monocoque building system.

At the present time with the cost of constructing houses, factories and other buildings escalating while the demand for such buildings increases, there is a need for a simple, inexpensive yet effective method of providing same.

An object of the present invention is to provide a method of building in which the main spacedefining envelope is a continuous composite membrane of generally uniform cross-section providing both structural stability and protection from external environmental and climatic effects and obviating the need for a separate structural framework.

With this object in view the present invention provides a monocoque building method comprising joining together side by side a plurality of elongate strips of material, each of similar "paraboloid" or "poiygonal" profile, to form, upon a predetermined foundation, a primary structure of any desired length without a separate skeletal framework transmitting load directly to the foundation.

The strips may conveniently be curved 'in situ' by gradual bending so as to stress the material and restrained under tension in natural "paraboloid" form by wires or cables connected between the free ends thereof or by being clamped at each end to rigid foundations.

Alternatively, the strips may be pre-curved at certain points along their length prior to gradual bending 'in situ' and restraining under tension. In this way it is possible to obtain an infinite number of alternative "polygonal" profiles and in combination with varying the length of the strips, alternative spans. Installation of pre-curved strips may also take place without gradual bending "in situ" and wherein the strips are not restrained in tension.

Optionally a secondary structure of a suitable sheeting material may be positioned inside the primary structure. The secondary structure should have a similar profile to the primary structure but have smaller lineal dimensions such that it takes up a position generally parallel to yet separated from the primary structure. The resultant intervening space is advantageously filled with a thermal insulating material which bonds to both structures to form a composite shell of inherent strength. The material forming the primary structure and/or the secondary structure may advantageously be corrugated. The thickness, profile and degree of corrugation of these structures and the thickness and density of the insulating layer are, of course variable depending upon the strength and thermal insulation factor required.

Flat prefabricated building panels consisting, in each case, of an inner and outer membrane and an intervening insulation layer have been available over recent years to hang onto a conventional skeletal framework on site. This skeletal framework is both costly and time consuming to fabricate and assemble, as well as being heavy and requiring substantial foundations to support it.

Moreover, as any deletions or additions to the actual building require corresponding alteration to the framework, extensive restructuring may postpone building completion dates and incur much greater costs than originally envisaged. Also, buildings erected using this framework method are limited in respect of versatility by their required framework since it is a permanent structure.

In a further monocoque building method in accordance with the present invention, it is proposed that at least some of the elongate strips of "paraboloid" or "polygonal" profile, which are assembled and joined together to form the completed structure, may be formed from a number of pre-fabricated composite panels similar to those already on the market. However, unlike existing known panels, the proposed panels are load-bearing on their own right without the need for any integral 6r non-integral structural frame transmitting load directly to the ground, and by nature of their construction, curved profile, method of linkage and means of resisting deflection are capable of supporting their own weight and any imposed load (including wind loading) to which they may be subjected in normal use. Moreover, the panels may be optionally stressed 'in situ'.

The invention will be described further, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a transverse cross section through a completed building in a first method in accordance with the invention illustrating the natural "paraboloid" profile, optional secondary structure with intervening thermal insulation, and cables restraining the composite shell in tension; Fig. 2 is a larger scale drawing of the detail at B of Fig. 1; Fig. 3 illustrates diagrammatically alternative "paraboloid" forms in a first method in accordance with the invention; Fig. 4 illustrates diagrammatically alternative "polygonal" forms in a second method in accordance with the invention using strips precurved at certain points along their length;; Fig. 5 illustrates diagrammatically how one type of precurved strip may be subjected to further gradual bending in-situ and restrained in tension in a "polygonal" form in the second method of the invention; Fig. 6 is a diagrammatic side view showing how the strips of Fig. 1 or Fig. 5 are assembled and joined together; Fig. 7 is a diagrammatic transverse crosssection illustrating a secondary structure formed with the same profile as the primary structure and located in position; Fig. 8 is a view similar to Fig. 7 showing thermal insulation in the intervening space between the primary and secondary structures; Fig. 9 is a transverse cross-section through a completed building in a third method in accordance with the invention illustrating the stiffening metal lattice or spaceframe structures, transverse cables and optional cable cross ties;; Fig. 10 is a larger scale drawing of the detail at C in Fig. 9; Fig. 11 is a larger scale drawing of the detail D in Fig. 9, or an alternative detail at B in Fig. 1 in place of restraining cables; Fig. 12 is a side view of a completed nondomestic building constructed in accordance with the method of invention; and Fig. 13 is a cut-away side view of a completed domestic building constructed in accordance with the method of invention.

As illustrated in Figs. 1 to 3, in a first monocoque building method in accordance with the present invention, a plurality of coated elongate strips 10 of material such as metal or plastics are, in turn, curved 'in situ' by gradual bending into "paraboloid" form so as to stress the material, and restrained under tension by wires or cables 11 connected between the free ends 1 2 thereof. The strips 10 are assembled side by side, as shown in Fig. 6, and joined together to form a primary structure 1 3 of any desired length upon foundation in the form of slabs 1 5. No skeletal framework is required to transmit load directly from the structure 1 3 to the foundation slabs 1 5.

As shown in detail in Fig. 2 the free ends 12 of the strips 10 rest on respective foundation slabs 15 and the wires or cables 11 are embedded in a layer of concrete or other suitable material, which forms the floor slab 1 6 of the finished structure, to ensure permanent tensioning of the strips 10.

In one variant of the method (not illustrated) a layer of insulating material is subsequently provided on the inside of the primary structure 1 3.

Of course, depending on the particular circumstances of the building, an insulating layer may additionally or alternatively be provided on the outside of the primary structure 13.

In another variant of the method, as illustrated in Figs. 1, 2, 7 and 8 a secondary structure 18 of suitable sheeting material and of similar profile to but smaller dimensions than the primary structure 1 3 is positioned inside the primary structure 13.

The secondary structure is substantially parallel to and separated from the primary structure 1 3 and the resultant intervening space 1 9 is filled with a thermal insulating material 20. The material 20 bonds to the two structures 13, 1 8 to form a composite shell of inherent strength.

The material forming the primary structure 13 and/or the secondary structure 1 8 may advantageously be corrugated. The thickness, profile and degree of corrugation of these structures and the thickness and density of any insulating layer 20 will, of course, depend upon the required strength of the finished building and the required thermal insulation factor.

The ends of the structure may be closed by sheets of similar material to the rest of the structure or alternatively brickwork, blockwork or conventional framework may be used.

Many variations of the above-described basic first method are, of course, possible. For example, instead of being heid under tension by the wires or cables 1 the free ends 12 of the primary structure 13 or the composite shell may be held together by restrainer bars (not shown) or simply be clamped to the floor slab 1 6 or the foundation slabs 15, e.g. by bolts 21, as shown in Fig. 11.

The strips 10 may be formed from a single sheet or from a plurality of sheets or panels connected together. In the majority of buildings, a number of strips 10 will be required to incorporate apertures for provision of windows 22 and doors 23, as shown in Figs. 11 and 12 in which case, where a secondary structure or skin 1 8 is provided, the apertures, will, of course, have to correspond.

To achieve a similar bending resistance over the length of such apertures to that of the sheeting material forming the remainder of each strip in the case of either single primary structure or composite shell (that is to say primary) and secondary structure), metal torsion bars or alternative methods of stiffening may be rigidly fixed alongside such apertures. This should ensure that the respective aperture-containing strip assumes an identical profile when viewed in end elevation to any strip without apertures. In most cases, the windows 22 and doors 23 will themselves be double-skinned for enhanced insulation, as shown in Fig. 11. Fig. 12 illustrates a finished non-domestic building formed by one of the above-mentioned methods of the invention.In many cases, it may be more convenient to locate the door and at least some if not all windows in the flat end walls of the structure.

In further modifications of the invention, local strengthening may be required to attain or maintain the proper stability of the structure as a whole. However such strengthening is always a means of reinforcement of the structure itself and does not constitute a load bearing skeletal frame transmitting load directly to the floor or foundations. Structures according to the invention designated for domestic application may be constructed with slate or tile 24 hanging on the external surface, as shown in Fig. 13.

Fig. 3 shows a variety of other natural "paraboloid" profiles which may be achieved by tensioning elongate strips 10 as previously described.

In a second method in accordance with the invention it is proposed that the strips 10 are bent into "polygonal" form by pre-curving at certain points along their length prior to installation on site and are subjected to further gradual bending 'in-situ' and restrained under tension (Fig. 5). By this method it is possible to obtain an infinite number of alternative transverse profiles, a few of which are illustrated in Fig, 4. Installation of precurved strips may however, also take place without further gradual bending and wherein the strips are not restrained in tension. All other details of construction in accordance with this second method are as described in relation to the first method wherein the strips are always tensioned.

In a third method in accordance with the invention, as particularly illustrated in Figs. 9 and 10 all the elongate strips taking up "paraboldid" or "polygonal" profile are formed from a plurality of panels 30 connected together.

The panels 30 are individually prefabricated in a factory and each comprises an inner and outer membrane 31, 32 with an intervening layer of insulating material 33 which also serves to bond the inner and outer membranes 31, 32 together.

The inner and outer membranes 31, 32 of some panels 30 undergo bending to required profile before they are bonded to each other by the introduction of a thermal insulator 33 therebetween. Such curved panels are obviously required to provide a junction between wall region and roof region in the eventual structure. The thermal insulator 33 may be cellular plastics foam and it may be introduced by the press injection method or by any other suitable technique to produce a fully bonded laminate of inherent strength.

These panels 30 are somewhat stronger than known prefabricated as the inner membrane 31 is thicker than hitherto and the insulating material 33 is thicker and/or denser than hitherto. This is necessary to enable the panels to be formed into a substantially self-supporting structure.

The prefabricated panels 30 are transported to the site where initially those panels forming the lower "side walls" are temporarily supported in position e.g. by metal lattices or spaceframes resting on temporary pylons, and fastened to the floor slab or foundations 34.

Some local strengthening of the structure may be required to impart the proper stability to the whole structure. In particular some additional strengthening may be needed at the junction of the longitudinal sidewalls and transverse roofing panels. As shown in Figs. 9 and 10 this strengthening may be accomplished by use of a metal lattice structure or a spaceframe 35 extending the full length of the building spanning each horizontal joint line. Preferably, as illustrated, the joints between the relevant panels 30 are arranged to occur at the mid point of greatest curvature of the composite structure and the spaceframe 35 is rigidly connected thereto. A joint between panels (not shown) may also be conveniently located at the ridge line of any building profile, particularly a profile of the type shown in Fig. 9, so as to reduce the necessary size of "roof" panels.Such joint may be reinforced by any pf the methods referred to or other suitable means. Local strengthening of the aforesaid types is always as a means of reinforcement only and never such as to comprise a load bearing frame, transmitting load directly to the floor slabs, or foundations.

The appropriate strengthening means, which in the described embodiment consist of spaceframes 35, are affixed to the upper extremities of the previously positioned side walls (formed of panels) and are themselves, to some extent mounted on the temporary supports during construction. Upper "roof" panels are subsequently lifted into place and connected to the sidewalls and/or the strengthening/joint reinforcing means found at the upper extremities of same.

In order to preserve the curvature of the upper "roof" panels, prevent downward deflection of same, improve span potential and as a restraint against imposed load, cables 36 are provided between the opposing spaceframes 35, or alternatively between points on the panels in that region or between alternative strengthening means. Tension is applied to these cables 36 to counteract all downward acting forces. Optionally such cables 36 can be further tensioned to stress the upper "roof" sections thereby increasing the curvature and enhancing the rigidity of the entire structure. Upon completion of the required tensioning, the temporary supports are removed.

As mentioned in connection with the previously described methods, the material used for the membranes 31, 32 of the composite panels 30 may be metal or plastics depending upon requirements. Additionally these membranes 31, 32 and the resultant panels 30 may be corrugated. As previously, the thickness, profile, and amount of corrugation of the panels 30 and the thickness and density of the insulating layers 33 may be varied depending upon the strength and thermal insulation factor required.

The foregoing method of construction is designed to permit subsequent removal, replacement or substitution of individual lower sidewall and upper "roof" sections without the need for temporary support and without disturbance of the remaining structure.

The "cold bridge" effect which might be created at main bolt positions is avoided by clipping capping pieces of faced thermal insulating material over the bolt heads.

Any apertures in the main building envelope such as windows 22 and doors 23 may be incorporated into the pre-fabricated panels 30 prior to forming, or may be inserted subsequently by cutting out material from the completed structure. Skylights or rooflights 37 may similarly take the form of pre-fabricated panels into which areas of transparent sheeting material, which may also be corrugated for additional rigidity, have been inserted. Alternatively they may be formed "in situ" using transparent material to span the void which would otherwise be occupied by a plain upper "roof" panel and sealing same onto adjacent panels.Industrial access doors of the roller shutter, vertical folding panel or any other appropriate type, may also be inserted into the composite shell in place of lower "sidewall" sections, such- doors may themselves be hung from the metal lattice or spaceframe structures previously described as strengthening means. As previously, it is envisaged that components inserted in apertures in the shell will be doubleskinned to maintain similar thermal insulating properties to that of the main building envelope.

Internal crosswalls may be constructed, e.g. of similar pre-fabricated panels or conventional brickwork/blockwork, to subdivide the finished building and these will also have the effect of bracing the structure. Where appropriate, tensioned cable cross ties 38, as shown in Fig. 9 may be added linking diametrically opposite points on the building cross-section which will further stabilise the structure against imposed side loading.

The composite panels proposed in accordance with the third method of the invention will no doubt prove to be of practical advantage in a number of other situations. For example, multiple span buildings may be created by the parallel alignment of any number of roof panels edge to edge, supported at their juncture by metal lattice structures similar to those already described and conventional columns, widely spaced because of the lightweight nature of the roof zone. In this way buildings of varying width as well as length may be constructed.

Also, "roof" panels may be used in conjunction with sidewall construction of a conventional type and sidewall panels in conjunction with conventional roof construction. In that sense each may be used independently as well as together in association with established methods of building.

Moreover, the panels may be used in more demanding structural conditions in association with a conventional skeletal framework sharing load transmission with the panels. In this situation the panels would remain in an active load bearing function but would be supplemented by additional non-integral structural means to the extent that increased structural performance was required.

Claims

1. A monocoque building method comprising joining together side by side a plurality of elongate strips of material, each of similar "paraboloid" or, "polygonal" profile, to form, upon a predetermined foundation, a primary structure of any desired length without a separate skeletal framework transmitting load directly to the foundation.

2. A method as claimed in claim 1 wherein the strips of material are subjected to gradual bending so as to stress the material "in situ" into "paraboloid" form and restrained under tension by wires or cables connected between the free ends thereof.

3. A method as claimed in claim 1 or 2 wherein the strips of material are subjected to gradual bending so as to stress the material "in situ" into paraboloid form and restrained under tension by being clamped at each end to rigid foundations.

4. A method as claimed in claim 1 wherein the strips of material are bent into "polygonal" form by precurving at certain points along their length prior to installation on site and are subjected to further gradual bending "in-situ" and restrained under tension by wires or cables connected between the free ends thereof and/or by being clamped at each end to rigid foundations.

5. A method as claimed in claim 1 wherein the strips of material are bent into "polygonal" form by pre-curving at certain points along their length prior to installation on site, but are not subjected to further gradual bending "in-situ" and are not restrained in tension, being bolted at each end to rigid foundations as a means of attachment only.

6. A method as claimed in any preceding claim wherein a secondary structure of suitable sheeting material and of similar profile to but smaller dimensions than the primary structure is positioned inside the primary structure.

7. A method as claimed in claim 6 wherein a space is provided between the primary structure and the secondary structure and the space is filled with a thermal insulating material which bonds to both structures to form a composite shell of inherent strength.

8. A method as claimed in any preceding claim wherein the material forming the primary structure and/or the secondary structure is corrugated.

9. A method as claimed in claim 1 wherein at least some of the elongate strips are formed from a number of sheets connected together.

10. A method as claimed in claim 9 wherein the sheets are pre-fabricated panels each consisting of an inner and an outer membrane with an intervening layer of insulating material which also serves to bond together the inner and outer membranes.

1 A method as claimed in claim 9 or 10 wherein a metal lattice or spaceframe provides local strengthening in the roof region and/or assists linkage between sheets or panels in this region.

12. A method as claimed in claim 9, 10 or 11 wherein cables are provided between opposing metal lattices or spaceframes or between points on the panels in the roof region to serve as a restraint against imposed load.

13. A method as claimed in claim 12 wherein the cables are tensioned "in situ" thereby to enhance the rigidity of the structure.

14. A monocoque building as formed by the method claimed in any preceding claim.

15. A monocoque building method substantially as hereinbefore described.

16. A monocoque building formed by the method described hereinbefore with reference to and as illustrated in Figs. 1 to 3, or in Figs. 4 to 8 orinFigs.9to 11 orinFig. 12 or in Fig. 13 of the accompanying drawings.