"Construction of Buildings"

INTRODUCTION

Field of the Invention

The invention relates to construction of buildings.

Prior Art Discussion

At present, the most common approach to constructing multi-storey buildings such as apartment blocks is to erect a structural frame of reinforced concrete or structural steel and then construct the walls, both internal and external, on site. The interior work such as second fix electrical and plumbing work is completed towards the end of the project.

hi recent years there has been a trend towards using modules or "pods" for particular rooms, particularly bathrooms and kitchens. This development has reduced the extent of finishing work performed on site, such as second fix plumbing and electrical fittings, tiling, and floor covering. However, considerable care must be taken to ensure co-ordination of the building frame on site and the pods in the factory so that the pods fit in as desired. Any error in construction of the frame in terms of physical dimensions of the supporting floor or external walls or in terms of provision of utility supplies matching those of the pods can be very difficult to rectify.

US4, 107,886 describes a construction method in which building modules are formed into a building by placing a layer of modules with one side wall of each module adjacent but spaced apart from one side wall of a different module. Concrete is poured into the space between the side walls to form a supporting column which is reinforced by bar girders extending out from the side walls. For multi-storey construction, a shoulder or saddle is formed on top of the supporting column for supporting modules to be placed directly above. While this method appears to speed up building construction, there is still considerable on-site work required.

US4,050,215 describes a modular construction method for a multi-storey building. U- shaped reinforced concrete modules are placed one atop the other to build up the building height, and at the top level there is a layer of modules having both floors and ceilings. These modules are used to provide the building frame and the remaining construction work is then performed.

EP0544609 describes a modular construction method, but gives very little detail about how this is achieved. It appears that a concrete mould is made and the module is then unmoulded.

The invention is directed towards providing for greater efficiency in construction of multi-storey buildings, both in terms of labour required and/or materials required. Another object is to provide a more consistent achievement of building quality. A still further object is to achieve better control of a project, with better predictability of dates for completion of activities. Another object is to reduce the extent of time and materials handling on site. A further object is to reduce construction materials waste.

SUMMARY OF THE INVENTION

According to the invention, there is provided a building pod comprising:

a structural floor,

structural walls secured to the structural floor, and

a structural ceiling spanning the structural walls,

wherein the structural floor, walls, and ceiling have sufficient load-bearing strength to support at least one other pod.

hi one embodiment, the structural walls each comprise a structural metal frame.

In another embodiment, the structural frame comprises box-section steel structural members.

In a further embodiment, the structural walls comprise vertical load-bearing studs.

In one embodiment, the structural floor comprises concrete cast in a structural frame.

In another embodiment, the floor structural frame comprises edge structural members having top horizontal flanges.

In a further embodiment, the structural walls are secured to the top flanges.

In one embodiment, the structural walls are secured by bolting to the top flanges.

In another embodiment, the edge structural members have a C-shape in cross section, comprising the top flange, a vertical web providing an edge surface of the floor, and a bottom horizontal flange.

In a further embodiment, the structural floor comprises reinforcing bar and meshes within the concrete.

In one embodiment, the structural ceiling comprises a plurality of vertical trusses interconnecting and spanning opposed structural walls.

In another embodiment, the trusses each comprise at least two horizontal structural members interconnected by vertical studs.

In a further embodiment, the structural members and studs of the vertical trusses are of box-section steel.

In one embodiment, each ceiling truss comprises a horizontal bearing plate overlying a wall plate of a structural wall.

In another embodiment, the bearing plate overlies a vertical stud of the structural wall.

In a further embodiment, the walls comprise non-combustible board cladding on both sides, with insulation such as mineral wool between the claddings.

In one embodiment, the interior is finished to finished room specifications with all required plumbing and electrical services and fitted furniture and sanitaryware.

In another embodiment, the building pod further comprises internal partition walls defining a plurality of rooms within the pod.

In a further embodiment, the building pod further comprises a balcony secured to the structural floor.

In another aspect, there is provided a method of manufacturing any pod as defined above, the method comprising the steps of

placing a floor frame on a platform and casting concrete into the frame to provide the structural floor, and

securing the structural walls or structural frames of the walls to the structural floor,

securing a structural ceiling frame to the structural walls to span and interconnect the structural wall frames,

constructing the interior of the pod to substantially complete the structural walls and ceiling to complete a room or rooms with in the pod, and

sealing the pod for transport and handling on site.

In one embodiment, the method comprises the steps of moving the platform from one work position to the next with successive steps being performed to erect the walls and the ceiling.

In another embodiment, the platform is moved on rollers.

In a further embodiment, the pod is lifted for transport by lifting it from lifting points on the floor.

In one embodiment, lifting rods are secured to the floor frame and extend to a height greater than the walls, and the pod is lifted by engagement of lifting tackle with the lifting rods.

In another embodiment, the rods extend upwardly from edge members of the structural floor frame and through the structural walls.

In a further embodiment, the rods engage in sockets between flanges of floor edge structural members.

In one embodiment, the platform is coated with oil to allow easy separation of the floor concrete from the platform.

In another embodiment, the structural ceiling is manufactured by placing a number of vertical trusses horizontally across a jig, securing internal cladding to the trusses, and lifting and flipping over the ceiling so that it spans the structural walls.

In another aspect, there is provided a method of constructing a building comprising the steps of:

manufacturing a plurality of pods in any method as defined above,

transporting the pods to a site where a podium structure or basement has been poured, and lifting and placing the pods to provide a multi-storey self-

supporting arrangement of the pods, with at least some pods atop lower pods and being supported by said lower pods,

erecting an outer wall leaf tied to exposed pod walls,

erecting a building roof over the pods, and

commissioning services to the pods.

In one embodiment, the pods are placed with structural walls aligned so that vertical load is transferred down through the pod structural walls.

In another embodiment, the method comprises the further step of erecting a stair or elevator core on site over the podium structure, and some pods are placed to butt against the core.

In a further embodiment, the method comprises the further step of embedding a metal plate in a wall of the core, and the floor of a pod butts against said embedded plate.

In one embodiment, an interface structural member is mounted between the floor and the embedded core plate.

In another embodiment, the interface structural member has a vertical flange welded to the. core plate and a horizontal flange welded to the pod floor.

DETAILED DESCRIPTIO OF THE INVENTION

Brief Description of the Drawings

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which:-

Fig. 1 is a flow diagram indicating the major steps of a method of the invention for constructing a multi-storey building;

Fig. 2 is a vertical cross-sectional view through part of a floor, a full wall, and part of a ceiling of a pod;

Fig. 3 is a perspective view from above of the structural frameworks of pods where they are placed one above the other and side-by-side, details such as cladding and insulation being omitted for clarity;

Fig. 4 is a diagram showing how a floor of a pod is manufactured, and Figs. 5 (a) and 5(b) are diagrams showing how lifting rods are inserted for lifting of a pod;

Fig. 6 is a vertical section at floor level of two adjoining pods, showing how they are placed on pods underneath;

Fig. 7 is a cross-sectional plan view showing interconnection of pods at a corner;

Fig. 8 is a vertical section showing how a pod fits atop another pod at an external wall;

Fig. 9 is a plan section showing construction of a window in a pod wall;

Figs 10 and 11 are a perspective view and a cross-sectional elevation respectively of a balcony of a pod;

Fig. 12 is a cross-sectional elevation of a parapet of a pod; and

Fig. 13 is a cross-sectional elevation showing connection of a pod floor to a stair core.

Description of the Embodiments

Referring to Fig. 1 a building is constructed in a method 1 by constructing in a factory a number of modules (or "pods"), transporting them to the site, placing them one atop the other and side-by-side to provide the rooms, and then erecting external cladding and a roof. The pods are complete, with no need for internal work to be performed.

Moreover, they provide the building structure, and so there is no need for any structural work to be done on site other than providing a ground-level floor. The extent of work done on site is considerably reduced in comparison with conventional construction methods.

In summary, the following are the steps for constructing a building:

10, Fabrication of a structural floor framework in a factory, using C-section structural steel around the edges and re-bar meshes inside.

11, Pouring self-levelling self-compacting concrete into the framework so that it is flush with the upper surfaces of the structural frame, to complete a structural floor.

12, Wall panels are separately manufactured by fabricating structural steel frames according to the building specification, inserting services and insulation, and securing board to the internal and external surfaces.

13, Placing the wall panels by crane onto the floor, one at each edge, and bolting each wall in place onto the floor framework.

14, Lifting rods are screwed into sockets in the structural frame at the edges of the floor so that they extend vertically at spaced-apart locations around the periphery of the frame. The lifting rods extend through the wall panels, passing through apertures in the wall panel frame.

15, 16, Structural steel vertical trusses for the ceiling are placed on a jig and board is secured in the upper plane using self-drilling and tapping screws.

17, The interconnected trusses are rotated by crane and placed over the wall panels, with bearing plates of the ceiling trusses resting on the wall panels, and then welded in place. The ceiling truss bearing plates are directly over wall panel vertical structural studs.

18 , The interior of the pod is finished in the manner of a conventional pod, with all services, fitted furniture, sanitary ware, tiling, windows, doors, and painting.

The pod is then sealed and no further interior work will be required until final inspection of the building. Because all of the interior work is done in the factory there is excellent quality control and little waste. This completes the factory work.

19, After covering with rain-proof GRP sheeting over the ceiling the pod is lifted into position on a lorry with a crane lifting tackle engaging the lifting rods, and so the pod is lifted from the floor.

20, hi parallel with the above factory work, on-site, a podium structure or basement is poured to provide a base for the building, and underground building services are incorporated according to the plans. Also a stair core and/or an elevator core is erected by casting re-enforced concrete.

21, When the site is ready, the pods are lifted into position with some side-by-side with opes in alignment, and the pods are placed one atop the other so that vertical load is applied down through the wall panels and floor frames of the pods. Pods adjoining the stair or elevator core are butt-jointed to the core. The pods are lifted from the bottom, as described in more detail below, thus avoiding distortion of the pods during lifting. The utility services protruding from the sealed pods are hooked up to the main building services, or alternatively this is left until final commissioning of building services in step

23. There is no need for construction of support structures above ground level, the pods themselves being self-supporting.

22, Finally, external cladding is secured to the external wall pod wall panels and a roof is constructed over the top-most pods.

23, The building services are commissioned.

The method is now described in more detail with reference to Figs. 2 to 13 inclusive.

Referring to Figs. 2 and 3 an individual pod 30 is shown. The main components are a structural floor 31, structural walls 32, and a structural ceiling 33.

The floor 31 comprises C-section edge frame structural members 35, poured concrete 36 with enmeshed re-bars 37 moulded in situ within the frame, and bolt fasteners 40 securing wall panels 32 to the floor 31.

The wall panels 32, each comprise a structural steel frame cladded on the outside by non-combustible board 45 and on the inside by board 46 and plasterboard 47. The frame comprises a wall plate 60 of angle-section steel, a bottom angle-section 62, and vertical box-section studs 61 at typically 600mm spacings.

The structural ceiling 33 comprises multiple vertical trusses 33 (a), each having upper and lower horizontal box-section members 50 and vertical box-section steel studs 51 at 300 mm spacings, a bearing plate 52 resting on top of the wall panel 32, and a vertical plate 53 to which the horizontal members 50 and the bearing plate 52 are welded.

The structural aspects of the pod are shown most clearly in Fig. 3, the non-structural items being omitted for clarity. The ceiling vertical trusses 33(a) terminate at both ends with the vertical plate 53 to which the bearing plates 52 are welded, and this diagram shows how the bearing plates 52 are carefully positioned on the wall panel angle-section wall plate 60 at locations directly over the box-section vertical studs 61.

Thus the vertical loading is transferred primarily down through successive bearing plates and wall panel vertical studs 61. Because of the structural interconnection of the vertical studs 61 and their close spacing (600 mm) the load is evenly distributed across the studs. This diagram also shows the bottom angle-section members 62 of the wall panels to which the vertical studs 61 are welded. All structural steel is surface treated for corrosion resistance. Fig. 3 also shows a corner vertical stud 70 welded to adjoining vertical studs 61. It also shows an interface plate 71 interconnecting four pods at their corners.

The walls illustrated are the external walls of the pod, and these are structural. The pod may contain a number of rooms defined by internal non-structural walls. Indeed, a pod may be a complete apartment or a combined hotel room or suite with integrated bathroom.

Manufacture of a floor 31 is shown in more detail in Figs. 4, 5(a) and 5(b). In the factory, a platform 80 is movable along a production line on rollers 81. It has a flat planar upper surface and the rollers 81 are carefully positioned so that the top surface of the platform is perfectly horizontal. A film of oil is deposited on the platform top surface. The fabricated floor frame with the edge members 35 is placed by crane onto the platform (or alternatively the floor frame may be fabricated in situ on the platform 80). Re-bar and steel meshes (shown generally as 37) are placed into the frame between the members 35, spacers (not shown) being used to provide a gap between them and the platform surface. Concrete with a low viscosity is poured into the mould formed by the edge frame members 35 until it is flush with the top surfaces of them. As shown in Figs. 5(a) and (b) sockets 85 are welded into the edge frame members 35 at a mutual spacing chosen according to the estimated final weight of the pod. Lifting rods 87 are subsequently screwed into the sockets 85 at threaded rod ends 86. The lifting rods 87 also have threaded upper ends 88 for subsequent engagement with lifting tackle of a crane.

After the wall panels 32 are positioned on the structural floor 31 the lifting rods are threaded through the wall panel (there are apertures in the wall plate member 60 and the bottom member 62 to accommodate the rods) to engage into the sockets 85 within

the floor frame. Connection of the wall panels to the floor and of the ceiling trusses 33 to the wall panels is shown most clearly in Fig. 3.As all of this work is done in the factory, overhead gantry cranes are used for lifting and placing the wall panels and ceiling assemblies. This lends itself to a large degree of automation and allows accurate placement of the various assemblies.

Fig. 6 shows details of how two pairs of pods are placed alongside each other and atop each other. The wall panels 32 have mineral wool insulation 105. It is clear from this drawing how vertical loads are transferred, directly down via the wall panels 32, the edge floor members 35 and the reinforced concrete of the floor adjacent the members 35.

A plan section is show in Fig. 7, in which insulation 111 is visible between pods for preventing fire spread and flanking sound transmission. There is a layer of insulation 110 directly on the outside of the external pod wall panels 32. This is applied on site or in the factory. An external stone cladding 112 is tied to the external pod walls. This diagram also shows the vertical angle-section structural member 70 interconnecting adjoining wall panels, vertical strips 116 of non-combustible board within the wall panels, a breathable membrane 115 on the outer surface of the insulation 110, and vertical timber battens 114 between polyisocyanurate/ polyurethane insulation 110 and the fire insulation 111.

Fig. 8 also shows how one pod is placed above another at an external wall. In this case, there is a stone cladding 130 tied to the pod external wall structural frame by ties 131. There is a layer 125 of polyiso/polyurethane insulation on the outside of the pod external walls, which is retained by wood battens 135. This diagram also shows mineral wool cavity barriers 136 and 137 separated by a stone support bracket 139.

An example of pod construction at a window is shown in Fig. 9. In this case the pod external wall has a layer 150 of insulation applied in the factory, and cladding 155 is tied in place over this on site. The window comprises a conventional window 140 secured in place offset from the wall panel by treated timber battens 157. This

drawing also shows a high-density insulation packer piece 156, and an end vertical strip of board 158 forming an internal window reveal.

A pod may be provided with a balcony, again manufactured off-site as an integral part of manufacturing a pod. Referring to Figs 10 and 11 a balcony assembly 200 is secured to an edge floor member 35 via an interface 201 having vertical connector plates 202. The balcony assembly 200 comprises a vertical connector plate 210, horizontal I-beams 211, horizontal angle beams 212, and a peripheral C-shaped member 215 with the flanges extending outwardly. This illustrates versatility of the construction method, and the avoidance of on-site work.

Referring to Fig. 12, a parapet 250 comprises a reinforced concrete slab 260 supporting a vertical parapet having a steel frame 255, inner slab panels 256, external stone cladding 257, and a hand-rail 252.

Referring to Fig. 13, a corridor floor 265 is simply an integral extension of a pod structural floor. It is supported by a pod 30 underneath, and it supports a wall 32. The floor 265 abuts a stair core 270, which was previously cast on site. The stair core comprises cast concrete 271 with embedded re-bars 272, and a side butting plate 278 cast into the side of the concrete 271. An angle-section member 275 is welded to the edge frame member 35 of the floor 265, and is in turn welded to the embedded plate 278. Concrete 276 is cast into the gap between the members 35 and 275.

This detail together with the pod-to-pod connections enable excellent lateral stability of the building to be provided. The stiff structural floors of the pods span as deep plates between the stair and elevator cores under lateral loads.

In the final building the cast concrete floors provide not only considerable structural strength but also fire and sound insulation. In some embodiments the concrete floor is covered by a soft covering matting, which reduces sound from impacts on the floor. Also, the floors 3 provide an excellent foundation for the wall panels. The structural continuity through the wall panels (particularly the vertical studs), the bearing plates 52, and the floor C-section frame members 35 provide sufficient load-bearing strength

to allow up to at least 10 pods to be placed one atop the other for a ten storey building. Because of the structural aspects, the work on site is dramatically reduced as compared to traditional construction methods. Figs. 7 to 9 for example illustrate how simple it is to finish an external cladding of the building, with excellent insulation being provided for the external pods. Construction of the cladding is not required to provide building structural support and so a wide variety of types of materials can be used at the choice of the architect. Figs. 11 and 12 further demonstrate the versatility, as a parapet or balcony can be manufactured off-site, with the option of connecting the balcony to the relevant pod off site or on site if desired.

The invention therefore achieves the benefit of factory-production of individual rooms or groups of rooms with completely finished interiors, on a much greater scale than heretofore. Here is also a dramatic reduction in the extent of work required on site because the pods are structural and so there is no need for supporting structures to be built on site other than the ground-level floor and a stair and/or elevator core. Also, there is a large reduction in the extent of building materials required, as manufacture is largely off site in the much more controlled environment of a factory. Because of the extent of work done off site, there is better quality control, less snagging work, and much more control of costs of construction.. Further, there is a dramatic reduction in time for construction on site, which is particularly advantageous where access to the site is restricted and there is disruption to adjacent premises, roads, or footpaths.

It will be appreciated that the invention overcomes the perception that one can not provide simultaneously both structural frames and room finishing work. Heretofore the approach had been to attempt modularity in terms of "drop-in" pods such as bathrooms, or pre-cast structural steel or formwork pods — not both together.

The invention is not limited to the embodiments described but may be varied in construction and detail.