WO2002064900A1

WO2002064900A1 - Modular structure

Info

Publication number: WO2002064900A1
Application number: PCT/CN2002/000035
Authority: WO
Inventors: James Edward Lawton
Original assignee: Gammon Finance Limited
Priority date: 2001-02-14
Filing date: 2002-01-22
Publication date: 2002-08-22

Abstract

A modular structure (1) is provided, the structure comprising a plurality of reinforced concrete modules. The modules comprise two side walls (6, 8) joined together by bolting means (31). It is advantageous if the bolting means have sufficient elasticity to achieve a constant clamping force between the modules throughout the life of the structure.

Description

Modular Structure

DESCRIPTION FIELD OF THE INVENTION The present invention relates to a modular structure for use in the construction of buildings and also to buildings constructed therefrom.

BACKGROUND OF THE INVENTION

Prior art document US 4,118,905 discloses a modular structure for a plural level building formed of a plurality of box-like modular units. Each unit has side walls, a roof and a floor and may be formed as a monolithic unit. The units further have cantilevered portions to enable them to be stacked one above the other in staggered configuration. In a structure constructed from this system, the weight of upper units would be borne directly by the units below them. Thus, the maximum number of storeys which could be constructed using this system would be directly related to the strength of the units at the bottom of the building. Consequently, this system would not be practical for the construction of high-rise buildings for example.

Further, the open ends of the modules cannot be joined together. Consequently, this system would not be practical for the construction of certain buildings as the size of room obtainable is limited by the size of an individual module.

Other modular construction systems are also known in the art. For example, US 3,990,193 discloses a modular construction system in which modules having side walls, a roof and a floor are constructed by joining four separate reinforced concrete panels together (for example by welding). The modules are then assembled between concrete walls which are joined by a pin connection at each storey. Again however, there is no provision in this system for joining together the open ends of modules in the structure.

Further, such panel construction systems have the disadvantage that the provision of jointing between the panels requires a significant amount of work thus increasing construction time and costs. In addition, the structure of the shear walls formed is not monolithic or continuous and so the walls cannot behave as a conventional wall having no pin joints and full moment continuity throughout the height of a building. Consequently, the system is not suitable for the construction of high-rise buildings as it is susceptible to progressive collapse and is generally lacking in strength.

GB 2320737A discloses a method of construction of multi-storey buildings in which structural concrete cross walls are cast in situ to hold pre-cast facade and floor panels of the structure in place. The precast floor slabs include joints to enable ends of the floor slabs to be joined together. However, this document does not disclose the provision of modules having a base, a ceiling and side walls and so shows a relatively complex and time consuming construction method. Further, in-situ poured concrete is used to join the ends of the floor slabs together such that a building constructed by this method is not easily demountable and, if demounted, then the precast floor slabs cannot be reused.

SUMMARY OF THE INVENTION

The present invention therefore seeks to provide a modular structure which overcomes the above problems.

From a first aspect, the present invention provides a modular structure comprising a plurality of reinforced concrete modules, the modules comprising two side walls joined together by a base and a ceiling, wherein a first and second module are joined together by bolting means.

This structure has the advantage that substantial cost savings can be obtained as the concrete modules can be prefabricated in a factory and then transported to a construction site ready for installation. This means that a structure can be assembled relatively quickly on site thus reducing the costs involved in construction due to the interest saved on the investment. Further, steel moulds may be used to produce the modules in the factory such that no timber wall soffit formwork is required. This has the advantage that the use of reusable steel moulds is more environmentally sound than the use of timber.

Further, as the modules are joined together by bolting means the structure is easy to assemble without the need to use in-situ concrete on site. The structure is also demountable in a way which allows the modules to be reused as they will not be damaged when the structure is demounted.

It is preferable that the bolting means provided between adjacent modules have sufficient elasticity to achieve a constant clamping action throughout the life of a modular structure according to the invention. This elasticity could be achieved by any suitable means and preferably, either bolts of sufficient length to provide the required elasticity, shorter bolts anchored against Belleville spring washers, or stressing strand are used to achieve the required degree of elasticity.

Preferably, the modules are integrally cast. This has the advantage that the modules are fabricated as single units such that no further assembly of the modules is required on site. In addition there are no joins between the side walls, base and ceiling, and so the modules are therefore not subject to potential errors that can occur where joins between the side walls, base and ceiling are formed e.g. by welding on site.

Each module could have walls at either end thereof so as to be fully closed. Preferably however, an open end of one module is configured to be joined to an open end of another module. This means that rooms larger than the internal dimensions of a single module can be provided where required.

Preferably, the open ends of respective modules are joined together by the bolting means. As an open end of one module is joined to the open end of another module, rooms larger than the size of a single module can be provided where required. It will be understood that any number of modules may be joined together as required to form a room having a length equal to the combined length of the modules in the direction in which the side walls extend.

Still more preferably, a profile joint is provided at an open end of each module, the profile joint being configured to mate with a cooperating profile joint provided at the open end of another module such that the open end of the module may be aligned with the open end of another module during assembly and bolting together of the modules.

The profile joint provides a structural, accurate and quick means of aligning the modules with each other during assembly and bolting together. Further, the provision of profile joints means that there is no need to fill or weld the joint between the modules prior to bolting them together. Thus, when the structure is demounted, the profile joints will not be damaged and this means that the modules can be reused after the structure is demounted.

Preferably both open ends of one said module are configured to be joined to an open end of respective other modules.

Preferably means are provided for covering the join between an open end of the said module and another module to obscure the join from the interior. This will provide a joint between the modules which is also secure against the ingress of fluids whilst at the same time being aesthetically pleasing to occupants of a room inside the modules.

The modules in the structure could be bolted together both side to side and end to end. However, this would mean that the weight of the upper modules would be carried by the modules below them. Thus, to reduce the module strength required for high rise construction, concrete may be poured directly between the side walls of adjacent modules to form load bearing structural walls.

This has an advantage in the time and costs saved by the reduced amount of formwork which is necessary. Further, as the modules are joined together by load bearing structural walls, the modules in the assembled structure do not have to carry the weight of all the modules above them.

Separate steel reinforcement could be provided in the walls of the modules and in the concrete walls poured between them. However, this would mean that the steel in the concrete walls had to be fixed after installation of the modules which would be time consuming and open to the increased incidence of error likely when work is carried out on site. Preferably therefore, one or more of the walls of the modules include steel reinforcement which projects outwardly therefrom such that the steel external of the modules is embedded in the concrete structural walls. This has the advantage that the steel reinforcement in the structural concrete walls is automatically installed by the installation of the modules and has the additional advantage of providing a structural link between the module walls and the poured concrete walls.

Preferably the reinforcement consists of a first set of steel bars embedded in said module wall and extending along the height thereof, and a second set of steel bars extending parallel to the first set of bars and joined thereto by a set of zigzag bars extending between the first and second bars.

Preferably the lower external portions of the side walls of each module taper inwardly towards the base of the said module. This provides a direct vertical load path from the poured concrete load bearing wall adjacent the base of a module onto the top edges of the module below thus making the module side walls an integral structural part of the load bearing structure.

The form of the module side walls therefore allows a direct vertical load path from the load bearing wall adjacent the base of a module onto the top edges of the module below to be provided in an assembled structure containing the modules thus making the module side walls an integral structural part of the load bearing structure. This has the advantage that structural continuity can be maintained through the end walls of the modules. The modules are designed to span individually between the walls with the advantage that the modules do not have to carry all the weight of the modules above them.

Preferably, the modules in a structure when assembled span between the concrete structural walls.

As an alternative means of supporting the weight of the upper modules in a structure, a frame structure which supports the modules could be provided and this would then obviate the need for poured structural concrete walls even in modular high rise buildings. In an alternative preferred embodiment therefore, the modules are joined together end to end and side to side by bolting means and a frame structure is provided to support the weight of the assembled modules.

In one preferred embodiment, the frame structure supports the weight of individual groups of vertically stacked modules. This is to limit both the cumulative weight to be supported by the modules at the bottom of each individual group and also to help limit the potential scope for progressive collapse to an acceptable level for the particular application.

In applications where the potential scope for progressive collapse is of particular concern however and/or if the sealing of joints between the modules is of particular concern or is required to be of a permanent nature, the use of in situ poured concrete to form load bearing structural walls which seal and further lock the modules together as described above is preferred.

Preferably a void is formed between the floor of an upper module and the ceiling of the module below it. This has the advantage of improving sound insulation between the modules.

Still more preferably, means are provided for sealing the gap between upper and lower modules at the external faces thereof. This will prevent the ingress of bulk rain water into the voids. Preferably the modules for external use further comprise a monolithic facade extending below the floor of the modules, and an upstand is provided on the ceiling of the modules, set back from the facade so as in use to stop any rain water from entering the void formed between upper and lower modules.

Still more preferably a drainage hole is provided in the module adjacent the vertical upstand. This drains any water which may enter the void from a module above, thus avoiding the risk of the water causing damage to the modules below by entering the modules.

Still more preferably vents are provided to allow the permanent controlled venting of the void formed between the floor of an upper module and the ceiling of a module below it. The vents may take the form of ducts provided in beams upstanding from the ceiling of a module or down standing from the base thereof. This has the advantage of preventing stagnation of the air in the void, and accumulation of condensation in the void and also discourages the growth of fungi in the void.

Preferably seals are provided to seal the area between adjacent modules such that leakage during concrete pours to form the concrete structural walls will be reduced.

The seals preferably comprise horizontal seals of a suitable material such as rubber provided in recesses in the upper surface of the lower modules only in order to readily accommodate horizontal tolerances between the upper and lower modules.

Inflatable seals which nest in use in vertical recesses in adjacent external edges of the modules may also be provided.

Preferably, a recess to hold a seal may be provided in each module which extends along the edge of both sides and of the roof of the module. This has the advantage that the sealant is provided over a sufficient length in the directions of movement to permit recoverable movement without damage and so effectively seals the joint between the profile joints of respective modules.

Preferably the sealant used has intumescent properties to provide fire resistance at the seal by blocking air flow.

Still more preferably, the sealant used at the open ends of the modules is a non- hardenable material. This improves the demountability of a structure using the sealant.

Preferably the modular structure includes modules which constitute one or more of the following parts of a building: a stairway, a central circulation area, a light well, a lift shaft and a riser.

Still more preferably the modular structure further comprises a lobby area, the floor, roof and end walls of which are formed by pre-finished, precast panels.

Preferably an adjusting shim is located at each of the four corners of the upper surface of each module such that when installed, the support points of a module arranged above the upper surface of another module bear directly onto the adjusting shims. This has the advantage of providing a compact arrangement within the modules which provides a direct vertical load path through which the weight of the structure may be borne either permanently or (if structural concrete walls are provided) temporarily until the structural concrete walls have been formed in the assembled structure.

Still more preferably the shim is made of a material having a suitable yield strength or suitable elastic properties to ensure that the shim will deform if it becomes overloaded. This will provide a means of dissipating energy should the structure be overloaded for any reason.

Preferably, to aid in construction of a building including the modular structures of the invention, a first module to be assembled is supported by shims which will not allow sliding motion and subsequent modules which are to be bolted to the said first module are supported by shims which do allow sliding motion. This has the advantage that the subsequent modules will automatically slide into the correct position against the first module when the connection bolts are tightened. Thus, only the first module in each group of modules which are bolted together needs to be positioned accurately by a crane when being lifted into position. The subsequent modules need only be positioned approximately on the shims which allow sliding motion, the accurate alignment being achieved by sliding motion as the modules are bolted together, thereby speeding up the erection process.

Preferably, the shims which allow sliding motion are formed by placing a lubricated shim on top of a shim which does not allow sliding motion.

Preferably, the elastic support provided by the support shims in the modular structure of the invention is transformed to provide a rigid permanent support after assembly of the structure. This may be achieved by filling each region immediately adjacent the shims in the structure with grout.

In one preferred arrangement, each of the adjusting shims is located in a fabricated shoe which is supported by a steel lifting pin.

In an alternative arrangement, each adjusting shim is displaced from the lifting pin. Nonetheless, the shims are preferably located close to the lifting points to maintain a direct load path through the modules arranged one above the other.

Preferably, the modules of the modular structure further include an elevated portion formed in the ceiling thereof. This elevated portion can be proportioned to fit in the space between the base of a module and downwardly depending beams provided thereon when arranged below that module. The elevated portion advantageously provides greater floor to ceiling height within the module over the area of the elevated portion which can be used to house building services or as storage space for use by occupants of the building.

In a further preferred embodiment, the modules of the modular structure may additionally or alternatively include a lowered portion in the floor thereof. This lowered portion can be proportioned to fit into the gap provided between the roof of a module and beams upstanding therefrom when arranged above that module. This has the advantage of increasing the floor to ceiling height within the module over the area of the lowered portion and the space within the lowered portion can be used for a bathroom sump or as additional storage for occupants of the building.

One further advantage to a structure including modules according to the invention is that the modules can be pre-surveyed in the factory before being transported to site. This will establish that the module dimensions are within tolerance and will also mean that any minor deviations from the ideal dimensions will be known in advance. The dimensions obtained from the pre-survey can be compared with an as-built site survey for a previously erected set of modules and corrections in the modules to be assembled can then be made in advance. This will reduce the delays in erecting the structure and will also allow the dimensions of the completed building to be within construction tolerances.

DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

Figure 1A shows a module of the modular structure according to the invention having one external wall;

Figure 1 B shows a module of the modular structure according to the invention having two open ends; Figure 1 C shows a module of the modular structure according to the invention having an external wall at the end opposite the external wall of the module of Figure 1 A;

Figure 2 shows a group of modular structures according to the invention arranged in several layers to form a three storey building;

Figure 3A shows a schematic plan layout of a block of flats constructed using a prior art method;

Figure 3B shows a schematic plan layout of a similar block of flats constructed according to the invention;

Figure 4 shows a typical joint between the floors of two modules in a modular structure according to the invention;

Figure 5 shows a typical joint between the floors of two modules in a modular structure according to the invention where the joint is partially obscured by a partition wall;

Figure 6A is a schematic plan view of an end wall of a module of a modular structure according to the invention;

Figure 6B is a sectional view along line CC of Figure 6A;

Figure 7 shows a section through a structural concrete wall joining two upper and two lower modules in a modular structure according to the invention;

Figure 8 shows a detail of a shim and lifting pin arrangement at the intersection between upper and lower modules in a modular structure according to the invention;

Figure 9 is a plan view onto a concrete structural wall formed between two pairs of opposing modules in a modular structure according to the invention; Figure 10 is a sectional view through the modules at point A of Figure 9;

Figure 11 is a sectional view through the modules at point B of Figure 9;

Figure 12A is a plan view onto a concrete structural wall formed between two adjacent modules in a modular structure according to the invention and showing the seals provided;

Figure 12B is a section along line AA of Figure 12A in enlarged scale;

Figure 13A is a side elevation of upper and lower pairs of modules in a modular structure according to the invention;

Figure 13B is a detail of the region marked A in Figure 13A;

Figure 14 is a plan view of a modular structure according to the invention;

Figure 15 is a side elevation of an alternative modular structure according to the invention;

Figure 16 is a plan view of the floor of the modular structure of Figure 15;

Figure 17 is an enlarged side elevation of the floor of the modular structure of Figure 15;

Figure 18 is a detailed view of the part marked A in Figure 15;

Figure 19 is a perspective view of a module of a modular structure according to the invention; Figures 20A and 20B are respective top and bottom perspective views of a module of a modular structure according to the invention;

Figures 21 A and 21 B are further respective bottom and top perspective views of an alternative embodiment of a module of a modular structure according to the invention;

Figure 22 shows a non-sliding shim for use in a modular structure according to the invention;

Figure 23 shows a sliding shim for use in a modular structure according to the invention; and

Figure 24 shows the shim arrangement at the join between two modules in a modular structure according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

As discussed above, the present invention provides a structure in which modules are joined together by bolting means to form a modular structure. As shown in Figure 1 , the modules of the preferred embodiment are made of reinforced concrete and are precast as integral units in factory conditions. The modules 1 comprise a base 2 and a ceiling 4, the base and ceiling being joined together by first and second side walls 6, 8 to form a four sided box structure. Depending on the type of structure to be built from the modules, the modules may include end walls at their front face 10 (as shown in Figure 1A), their rear face 12 (as shown in Figure 1 C), or at both ends (not shown). Alternatively, the modules may be open at both ends (as shown in Figure 1 B).

The open ends of the modules are configured to allow attachment to a further module as will be described further below. As shown in Figure 2, the modules are arranged one above the other in use to form a multi storey building. The modules can be arranged in any desired configuration to provide a required building layout. In the arrangement of Figure 2, a first module 14 with an end wall at the front face thereof is joined to a module 16 which is open at both ends, the other end of the open module being joined to a module 18 with an end wall at the rear face thereof. Thus, the resulting structure will include a single room on each floor which is the width of one module but the length of three modules. As shown, further modules are then arranged in the same way on the second 20 and third 22 floors of the building. If required, modules can also be arranged side by side to provide a building of greater width. The prefabricated modules can include an external facade with all of its architectural features and can also include permanent internal fittings such as partition walls, floor and wall finishes, bathroom fittings, kitchen fittings, glazed windows, as well as electrical fittings, plumbing and other services.

As shown in Figure 3A, in a standard apartment block constructed using prior art methods, the external structure is defined by structural walls 24 which are constructed on site using traditional formwork methods together with precast facade elements 26 attached to the structural walls 24. The floor slabs of the structure are also cast on site. The construction of such structures therefore requires substantial on-site time. In contrast, a structure according to the invention can be assembled on site in a relatively short time as the modules are prefabricated in a factory. As shown in Figure 3B, a structure according to the invention consists of modules 1 which are joined together end to end by bolting, and the sides of which are joined together by load bearing reinforced concrete walls 28. The provision of load bearing concrete walls 12 makes the structure particularly suitable for the construction of high rise buildings (buildings having 20 floors or more). The way in which these walls are formed will be described further below. For the construction of low or medium-rise buildings, the load bearing concrete walls can be dispensed with and the modules can be bolted together side by side also. This would have the advantage of making the structure fully demountable and easy to reassemble repeatably while the structure can be assembled in a simpler, quicker manner.

High rise structures may also be generated without the use of load bearing concrete walls between and around the modules by the provision of a supporting structural frame at suitable elevations of the building, thereby providing a high rise structure in which the modules are demountable and reuseable. Alternatively, if a building is not required to be demountable, a high rise structure including both a supporting structural frame at suitable elevations of the building and load bearing concrete walls between the modules can be provided.

The modules may also include stairways, central circulation areas, light wells, lift shafts, risers, lobby areas and service compartments and can be arranged to provide a commercially acceptable, high efficiency ratio of habitable to service areas within buildings which use the invention. They also permit the use of pre-finished, precast panels to form the floor, roof and end walls of the lobby area in a building.

This enables a uniform construction method to be used across the floor plan so that the wings and core area may be constructed at the same balanced rate using the same labour and equipment. Traditionally different highly specialized and costly methods have had to be used such as jump forming or slip forming to construct these core areas ahead of the wing areas to enable a faster overall floor construction cycle.

The use of precast stair flights is a well known construction method and it is more preferable if this principle be expanded for modules to incorporate items such as but not limited to continuous flights of stairs, landings, stairwell enclosure, supporting corbels to the lobby areas, windows, lobby areas, water metre rooms and electric meter rooms. As with other modules these stairwell modules are designed to span between the in-situ walls to eliminate the problems associated with stacking and to enable efficient high-rise construction.

It is preferable to arrange the stair flights so that they are independently supported within each module to eliminate the problems associated with stacking and to enable efficient high-rise construction. Additionally it is preferable that they be arranged so that they form continuous flights of stairs as the modules are assembled It is preferable to include lift-shaft modules in the core area to include items such as but not limited to, lift shafts, supporting corbels to the lobby areas, windows, lobby areas, water meter rooms and electric meter rooms. As with other modules this lift- shaft module is designed to span between the in-situ walls to eliminate the problems associated with stacking and to enable efficient high-rise construction.

It is intended that the inherent accuracy of the modular system will significantly expedite and reduce the cost of subsequent lift installation as compared to traditional lift shafts with much greater construction tolerances.

It is also possible to include a complimentary precast floor system to the lobby to remove the requirement for any slab construction in the core area, to be consistent with the wing areas.

It is particularly preferable that the core modules be surrounded by the in-situ core wall 28 as shown in Figure 3B. This is to ensure structural integrity for high-rise construction, to lock the modules together and to seal off the inside of the core from the weather, particularly wind driven rain at high elevations.

In one preferred embodiment of a structure according to the invention, the modules are rectangular in shape and have a width of 2.5m to satisfy the transport requirements of Hong Kong. However, rooms of a width greater than 2.5m are often required. Thus, in the structure of the invention two or more modules can be joined together by their open ends in order to form a larger room. This means that the joints between modules will occur across the floors, ceilings and walls of rooms which are wider than 2.5m. A precise fit between the modules is therefore desirable both to provide a flush internal surface which is imperceptible to occupants of the room, to provide a strong mechanical connection between the modules and to provide adequate sealing in the joints against ingress of in-situ concrete and for fire safety.

As shown in Figures 4 and 5, the open edges of the modules are cast as respective halves of a profile cast joint 30 to enable the modules to be securely fastened together. Figure 4 is a sectional view through the floors 2 of two modules. As can be seen, the edge of the first module is formed with a profiled projection 32 extending along the length thereof. The edge of the other module is formed with a corresponding profiled cast recess 34 for receiving the projection 32. During assembly of the modules, the projection and recess will be mated to automatically align the modules relative to one another. The profiles are locked together by integral keyways (not shown) so that the edge surfaces of the two module floors are flush to within about 2mm. These joints have the advantage that only a small amount of site finishing work is required. The modules are then bolted together as will be described further below to provide a permanent structural connection between them.

The modules may be dry fitted for installation of finishes and split for transportation to site. Once the modules have been temporarily bolted together, a timber floor 38, tile or other finish if preferred is then installed on the floors 2 of the modules using a thin bed adhesive layer 36, or other fixing method. A gap in the finishing material is left directly above the joints between the modules. This gap will be filled in by a strip of the same finishing material once the modules are permanently assembled on site.

This provides a joint which will not be visible to an occupant when inside the room formed by the modules.

Similarly, bathroom, kitchen and core walls may be treated in a like manner. For walls and ceilings that are to receive a painted or wallpapered finish, the internal face of the module is finished with a tapered edge. Once the modules have been permanently fitted together the joint in the wall and ceilings are infilled using a proprietary filler incorporating a layer of scrim tape in the thickness of the filled joint. Following a final coat of paint or wallpaper covering, the joint will not be visible to the occupant when inside the room formed by the modules.

In order to ensure that the joint is also water and fire proof to the external environment, a suitable jointing compound is inserted into the gap between the two halves of the profile joint 30. This has the added advantage of making the joint grout tight to resist leakage during in situ concrete pours.

Figure 5 shows a variation of the internal finish to the joint in Figure 4. As shown, a partition wall 42 is provided in the first module adjacent the open edge thereof. The modules may be temporarily bolted together for installation of finishes and then split for transportation to site. A timber floor 38, or other finish if preferred, is then installed on a thin bed adhesive or by other alternative means. Once the modules have been permanently fitted together and the joint locked, a timber skirting board 44, or other material if preferred, is attached to the partition wall to cover the joint 30. Thus again, the joint between the two modules would not be visible to an occupant of the room.

The floors 2 of respective modules are bolted together by long clamping bolts 31 which pass through the modules as shown in Figure 17. In an alternative embodiment which is not shown, stressing strand could be used in the place of the long clamping bolts. The long clamping bolts 31 or stressing strand are provided in either side of the module floors 2 as shown in Figure 16.

In contrast to this, the edges 33 of the module ceilings 4 are joined together by short bolts 35 as shown in Figure 18. Belleville spring washers 29 are provided adjacent the bolts to make the bolted connection elastic as discussed below. These short bolts could also be used alternatively to join the modules together via their floors or side walls.

It is desirable that the clamping action of the bolts joining the open ends of the modules together be maintained at an even and constant value throughout the life of the building. This is to ensure that no differential movement can occur across the joints between modules so that no cracking of finishes may occur and also that the joint sealant also remains intact so that it may continue to function correctly. Additionally, this clamping function may be used to further enhance the composite nature of the floor slabs of the modules, so that they may generate the structural properties of a traditional monolithic floor slab. The clamping may also be used to further reduce the potential for cracks to occur in decorative finishes to floor, ceiling and/or walls joints between modules during the life of a building. This constant clamping action may be achieved by but not limited to any of the following means:

1. The introduction of Belleville spring washers 29 into the clamping bolt system to provide consequent elasticity, so as to be able to maintain an effectively constant clamping force despite any small subsequent movements of the bolt anchorages or shrinkage of the concrete modul es. This is shown in relation to the ceiling bolts in Figure 18.

2. The use of clamping bolts 31 of sufficient length and consequent elasticity so as to be able to maintain an effectively constant clamping force despite any small subsequent movements of the bolt anchorages or shrinkage of the concrete modules. This is as shown in Figures 15 to 17.

3. The use of stressing strand (not shown) of sufficient length and consequent elasticity so as to be able to maintain an effectively constant clamping force despite any small subsequent movements of the bolt anchorages or shrinkage of the concrete modules.

In one embodiment, five modules 1 a to 1e are bolted together end to end as shown in Figure 14 to form a modular structure including a single internal space having a length equal to the length of five modules. The short bolts 35 extending between respective module end portions are shown in this figure. The modular structure once bolted together can then be used in the construction of a building.

The building is constructed by lifting all of the modules or modular structures of a first storey into place and joining the open ends of modules together where required. As shown in Figure 3B and discussed briefly above, structural reinforced concrete walls are then formed between the modules to hold them together if required for the type of structure being built (e.g. a high rise structure). As shown in Figures 6A and 6B, the precast side walls 6,8 of the modules include steel reinforcement. In the walls of the modules which will be adjacent the structural concrete walls 28, this reinforcement consists of latticed rebar which protrudes externally of the module wall 6,8. As shown in Figure 6B, the reinforcement comprises a first set of bars 46 embedded in the module wall 6 which is joined to a set of second parallel bars 48 external of the module wall by means of a set of zigzag bars 50. This arrangement gives adequate local lateral stability and reinforces the modules sufficiently to allow them to resist transportation forces, handling forces and the pressure produced by in situ concrete pours in which the walls of the modules are used as the temporary formwork. In addition, the rebar is compatible and complimentary with the permanent structure built around the modules and the provision of reinforcement which projects externally of the modules allows the module walls to behave compositely with the structural concrete walls formed between them. The assembled modules are arranged such that gaps are left between certain adjacent modules for the formation of concrete structural walls 28. The external reinforcing bars 48 of the module walls 6,8 extend into these gaps. Concrete is then poured directly into the gaps, i.e. the module walls 6,8 are used as formwork for the concrete pour such that additional formwork only need be provided in areas where the modules do not extend on all sides of the wall to be poured. This results in substantial time and cost savings due to the reduction in fixing and striking of temporary formwork panels.

Further, the external reinforcing bars 48 of the module walls 6,8 form the reinforcement within the poured concrete walls. This has the advantage that the module walls 6,8 behave compositely with the structural concrete walls 28 so that the cumulative thickness of the module walls and the concrete structural walls can be minimised while retaining the required weight bearing capacity and rigidity of the structure. Further, as the steel reinforcement for the concrete structural walls is prefixed to the module walls under factory conditions, there is reduced potential for steel fixing errors which can occur when steel is attached on site. The provision of structural concrete walls which bind the modules together allows the formation of a structure acting as a single monolithic structure. This is because the natural shrinkage which occurs during the curing of the concrete structural walls relative to the module walls which have already shrunk through curing, generates a beneficial clamping effect between the module joint surfaces, thereby enhancing the structural behaviour and also reducing the potential for cracks to occur in decorative finishes to module joints. As the module floor slabs are locked together by the concrete structural walls 28, the module floor slabs of the structure behave in a structurally similar manner to the conventional floor slabs of a frame-type high-rise structure and so maintain the advantages of conventional in situ construction such as robustness, durability, fire resistance and insulation. In a preferred embodiment of the invention, modules held together by concrete structural walls are used both in the core and the wings of the structure. This will maximise the advantages of strength and stability provided.

The external edges of each module taper inwardly adjacent the base (see Figure 7).

Thus, concrete poured between two adjacent modules will flow into the free area 52 left by the taper and rest on top of the upper corners 54,56 of the two modules below.

Thus, the concrete provides a direct vertical load path from the concrete structural wall down onto the module walls 6,8 below. This enables the thickness of the module walls to be included in the total width of the structural load bearing wall for the assessment of load bearing capacity. The total width of the wall may also be used for the assessment of structural stiffness.

The structural walls described support the weight of each module in the structure, each module spanning between two walls. In modular structures where such structural weight bearing walls are not provided, each module has to support the cumulative weight of the modules above. This means that the height of the modular structure is limited by the structural strength of the modules at the base of the structure. Further, the provision of weight bearing structural walls means that the structure has inherent structural stability and so is resistant to progressive collapse in the same way as a conventional high-rise structure. Thus, damage due to the accidental loss of a module, due for example to a gas explosion, cannot propagate throughout the structure as the other modules in the structure are all self-supporting and integral with the main structure.

In embodiments of the invention where no structural concrete walls are provided, the weight of the structure is borne by the end walls at either end of each modular structure formed by a set of modules bolted together. The modules span between these end walls so that no in-situ slab construction is required in these parts of the building.

Figure 8 shows one possible layout of a lifting pin 58 and shim 60 at the joint between upper and lower modules. As shown, the lifting pin 58 and shim 60 are arranged to be coincident and compact, reducing the plan area required for these elements and thus increasing structural and mechanical efficiency of the structure. The adjusting shim 60 is located in a fabricated shoe 62 (which is located and supported by the steel lifting pin 58 of the lower module). A lifting pin and shim arrangement of this type is provided at each of the four corners of each module. The support point of the upper module when in position bears directly onto the shims 60, thereby providing a direct load path vertically through the strong points of the module which are located at each of the four integral corner posts. If structural concrete walls are included in the structure, once the walls have been formed this load path will be redundant. The shim is made of a block of material having a suitable yield strength or suitable elastic properties to ensure that the shim will deform should it become overloaded in some way. Thus, the overloading will not cause damage to the module or change the intended distribution of the clamping forces in the module joints.

An alternative layout of the shim is shown in Figure 24. This is a plan view onto the corners of two adjacent modules. As shown, in this arrangement the shims 60 are slightly displaced from the lifting pins 58. A channel 57 for a rubber seal is provided around the area in which grout is to be poured around the shims 60. This layout has the advantage that as the shims are not located above the lifting pins, no specially fabricated shim shoe is required.

It is particularly advantageous that the shim material should be elastic when there is a series of two or more modules which are joined together. This ensures that normal construction tolerances can be absorbed by the differential elastic compression of the shims, to the extent that the series of modules remains effectively supported with even, supporting forces, as designed. This in turn ensures that there is no bending induced into the series of modules so that the clamping force remains evenly distributed around the profile cast joint in the intended manner. Consequently the precision interlocking and sealing properties of the joint remain as designed despite construction tolerances of the supporting surfaces.

It is also advantageous that soon after erection the elastic temporary support provided by the support shims be transformed into a rigid permanent one by for example grouting the area 59 immediately around the shims as shown in Figure 24. In an alternative method, additional shims could be wedged into the area immediately around the shims to transform the elastic temporary support into a rigid permanent one.

It is also advantageous for the erection process that the first module in a set to be positioned is supported on non-sliding shims (shims which do not allow sliding motion as shown in Figure 22) and that subsequent modules are supported on sliding shims (shims which do allow sliding motion as shown in Figure 23). This is so that these subsequent modules automatically slide into the correct position up against the first or previous modules, as the clamping bolts are tightened. Consequently only the first module needs to be positioned accurately by the erection crane thereby speeding up the erection process.

The provision of sliding shims is achieved by placing an additional, lubricated shim 61 on top of the naturally non-sliding supporting shim 60. The arrangement of the modules of the invention one above the other means that voids 63 are formed between the ceiling 4 of a module and the floor 2 of a module above. These voids are advantageous in increasing sound insulation between storeys of a building. They also increase thermal insulation thus providing potential savings in heating and air conditioning. A void 63 between the modules is shown in Figure 10 from which it can be seen that the gap 64 in the facade 66 between the front faces of upper and lower modules may be sealed horizontally if desired and additionally, a vertical upstand 68 is provided behind the gap so that any rain penetrating through the gap will be held back by the upstand. A drainage hole 70 is provided just in front of the upstand 68 as shown in Figure 11.

Because a drainage path is provided in the void 63, this provides an extra barrier against water from an upper module seeping into a lower module. To enhance drainage still further, free draining flashing 61b is provided over the module roof junctions and the roof slabs of peripheral modules of a structure can be arranged to slope so as to drain outwards towards the drainage vent.

Vertical, riser type of vents 72 are located between the junction of two adjoining facades as shown in Figure 9. They run vertically up the full height of the building and are vented internally behind the facades at each floor, to provide controlled ventilation of the floor voids 63 to prevent stagnation of the air. These vents thus prevent stagnation of the air, accumulation of condensation and also discourage the possibility of fungal growth.

A further feature of the modules of the invention is that they are provided with seals to prevent grout leaking out when the concrete structural walls are poured using the modules as temporary formwork. Thus both horizontal 74 and vertical 76 seals are provided. The seals may accommodate a large range of gap widths between the modules. The horizontal seal 74 is located in a recess 78 in the top of the lower modules so that it will not be displaced when a module is placed above the lower module (see Figures 12A and 12B). The underside sealing surface 80 of the top module is totally flat so that it may be located in a slightly offset plan location without compromising the function of the seal. This allows the vertical alignment of the building to be adjusted and corrected as required during erection. The horizontal seal 74 comprises a suitable material arranged to extend along the adjacent sides of the two adjacent modules and to be joined in a loop at the join between the two modules. In the preferred embodiment, the seal is made of rubber and preferably of foamed rubber and is square in cross section.

The vertical seals 76 provided between the modules are inflatable and reusable. As shown in Figures 12A, 12B, 13A and 13B, these seals are inserted into vertical circular recesses 82 formed between the adjoining ends of the facades 66 of two adjacent modules. These seals are not inserted until after the modules have been assembled as there is a strong likelihood that any seal would be knocked off during the installation of the adjacent module.

In an alternative embodiment as shown in Figures 19 and 24, the recess 82 extends along both sides and the top edge of the module. This has the advantage that the sealant has sufficient length in the direction of movement to permit recoverable movement without damage. Fire resistance can be provided by the intumescent properties of the sealant. Further, a non-hardening sealant is used to ensure that the structure remains demountable.

In one embodiment as shown in Figures 20A and 20B, each module is formed with an elevated portion 61 in the ceiling which nests up between the downstand beams 63 of the module directly above so that the floor to ceiling height inside the module is increased. The increased height can be used to accommodate building services equipment or to provide storage space.

As shown in Figures 21 A and 21 B, a lowered portion 65 can also be provided in the floor 2 of a module which nests down between the upstand beams 67 of the module directly below, so that the floor to ceiling height within the module is again increased over the area of the lowered portion. This could be used to accommodate sumps for sunken bathroom layouts or as storage space.

Using such modular structures and methods as described above in the construction of high-rise structures can result in a floor by floor construction cycle time of only two days as compared with a typical time of 6 days using conventional construction methods. Thus, the present invention provides a substantial saving in construction time and hence costs without compromising the quality of structures obtained.

Further, the bolting together of the modules renders buildings constructed from the modules highly demountable as the clamping bolts or stressing strand need only be removed to demount the building. Thus, the buildings can be demounted and reassembled as many times as required.

Additionally, the use of bolting means to join the modules together in conjunction with the use of the sliding and non-sliding shims and the provision of profile joints in the open ends of the modules means that structures made up of the modules are easily and accurately assembleable when compared to prior art systems.

The embodiments of the invention described above are preferred embodiments only and so are not intended to be limiting. Thus, the skilled person would understand that various alterations could be made to the structures described without departing from the scope of the invention as defined in the appended claims. For example, the modules shown are all rectangular in shape. However, this need not necessarily be the case and so the invention is also applicable to modules of any shape which can be assembled as required.

Claims

1. A modular structure comprising a plurality of reinforced concrete modules, the modules comprising two side walls joined together by a base and a ceiling, wherein a first and second module are joined together by bolting means.

2. A modular structure as claimed in claim 1 , wherein the bolting means have sufficient elasticity to achieve a constant clamping force between the modules throughout the life of the structure.

3. A modular structure as claimed in claim 2, wherein bolts of sufficient length to provide the required elasticity, shorter bolts anchored against Belleville spring washers, or stressing strand are used to achieve the required degree of elasticity.

4. A modular structure as claimed in claim 1 , 2 or 3, wherein the modules are integrally cast.

5. A modular structure as claimed in any preceding claim, wherein an open end of one module is configured to be joined to an open end of another module.

6. A modular structure as claimed in claim 5, wherein the open ends of respective modules are joined together by the bolting means.

7. A modular structure as claimed in claim 5 or 6, wherein a profile joint is provided at an open end of each module, the profile joint being configured to mate with a cooperating profile joint provided at the open end of another module.

8. A modular structure as claimed in claim 5, 6 or 7, wherein both open ends of one said module are configured to be joined to an open end of respective other modules.

9. A modular structure as claimed in any of claims 5 to 8, wherein means are provided for covering the join between the open ends of the said modules to obscure the join from the interior.

10. A modular structure as claimed in any preceding claim, wherein the modules are joined together both side to side and end to end by bolting means.

11. A modular structure as claimed in any preceding claim, wherein a frame structure is provided to support the weight of the assembled modules.

12. A modular structure as claimed in any preceding claim, wherein the modules are joined together by load bearing structural walls formed by pouring concrete between the side walls of adjacent modules during construction.

13. A modular structure as claimed in claim 12, wherein one or more walls of the modules include steel reinforcement which projects outwardly therefrom such that when installed the steel external of the modules is embedded in the concrete structural walls.

14. A modular structure as claimed in claim 13, wherein the reinforcement consists of a first set of steel bars embedded in said module wall and extending along the height thereof, and a second set of steel bars extending parallel to the first set of bars and joined thereto by a set of zigzag bars extending between the first and second bars.

15. A modular structure as claimed in claim 12, 13 or 14, wherein the lower portions of the side walls of each module taper inwardly towards the base of the said module.

16. A modular structure as claimed in any of claims 12 to 15, wherein the modules span between the structural concrete walls.

17. A modular structure as claimed in any preceding claim, wherein a void is formed between the floor of an upper module and the ceiling of the module below it.

18. A modular structure as claimed in claim 17, wherein means are provided for sealing the gap between upper and lower modules at the external faces thereof.

19. A modular structure as claimed in claim 17 or 18, wherein the modules for external use further comprise a monolithic facade extending below the floor of the modules, and wherein an upstand is provided on the ceiling of the modules, set back from the facade so as in use to stop any rain water from entering the void formed between upper and lower modules.

20. A modular structure as claimed in claim 19, wherein a drainage hole is provided in the module adjacent the vertical upstand.

21. A modular structure as claimed in any of claims 17 to 20, wherein vents are provided to allow the permanent controlled venting of the void formed between the floor of an upper module and the ceiling of a module below it.

22. A modular structure as claimed in any preceding claim, wherein seals are provided to seal the area between adjacent modules when installed.

23. A modular structure as claimed in claim 22, wherein the seals comprise horizontal seals provided in recesses in the upper surface of the ceilings of the modules.

24. A modular structure as claimed in claim 22 or 23, wherein the seals comprise inflatable seals which nest in use in vertical recesses in adjacent external edges of the modules.

25. A modular structure as claimed in claim 22, 23 or 24, wherein a recess which extends along the edge of both sides and the roof of a module is provided for holding a seal therein.

26. A modular structure as claimed in any of claims 22 to 25, wherein the seals comprise a material having intumescent properties.

27. A modular structure as claimed in any of claims 22 to 26, wherein the seals comprise a non-hardenable material.

28. A modular structure as claimed in any preceding claim in which one or more of the modules constitute one or more of the following parts of a building: a stairway, a central circulation area, a light well, a lift shaft, a riser, a lobby area and a service compartment.

29. A modular structure as claimed in any preceding claim, the structure further comprising a lobby area, the floor, roof and end walls of which are formed by pre-finished, precast panels.

30. A modular structure as claimed in any preceding claim, wherein an adjusting shim is located at each of the four corners of the upper surface of each module such that when installed, the support points of a module arranged above the upper surface of another module bear directly onto the adjusting shims.

31. A modular structure as claimed in claim 30, wherein the shim is made of a material having a suitable yield strength or suitable elastic properties to ensure that the shim will deform plastically or elastically if it becomes overloaded.

32. A modular structure as claimed in claim 30 or 31 , wherein a first module is supported by shims which will not allow sliding motion and subsequent modules which are joined to the first module by bolting means are supported by shims which do allow sliding motion.

33. A modular structure as claimed in claim 32, wherein the shims which allow sliding motion are formed by placing a lubricated shim above a shim which does not allow sliding motion.

34. A modular structure as claimed in any of claims 30 to 33, wherein each said adjusting shim is located in a fabricated shoe which is supported by a steel lifting pin.

35. A modular structure as claimed in any preceding claim, wherein the modules of the modular structure further include an elevated portion formed in the ceiling thereof.

36. A modular structure as claimed in claim 35, wherein the elevated portion is proportioned to fit in a space between the base of a module and downwardly depending beams provided thereon when arranged below that module.

37. A modular structure as claimed in any preceding claim, wherein the modules of the modular structure include a lowered portion in the floor thereof.

38. A modular structure as claimed in claim 37, wherein the lowered portion is proportioned to fit into a gap provided between the roof of a module and beams upstanding therefrom when arranged above that module.