Field

This disclosure relates, in one aspect, to a connector for connecting volumetric modules of a modular building system. In another aspect, this disclosure relates to a modular building comprising a plurality of volumetric modules coupled together by connectors of the type disclosed herein.

Typically, Modular Building Systems (MBSs) are a sub-category of Modular Construction referring to the highest level of prefabrication, in which entire preengineered box-shaped volumetric framing units (referred to herein as volumetric modules) are manufactured within tight tolerance levels in a controlled factory environment, delivered to the location of the project on a ‘just-in-time’ basis, and finally assembled into a complete building by means of inter-module connectors.

In the field of modular construction, it is the case that connections between volumetric modules can affect the structural behaviour of modular buildings constructed from those modules, particularly in the context of resisting the effects of meteorological or geological events, such as extreme weather conditions or earthquakes.

A variety of connectors for connecting volumetric modules have previously been proposed. These previously proposed connectors have aimed to provide practical and straightforward assembly procedures, while also aiming to provide an adequate resistance to lateral forces (as might be experienced in a seismic or extreme weather event).

We have identified that these previously proposed connectors can exhibit limitations when it comes to demounting and reusing volumetric modules, particularly in the aftermath of a damaging meteorological or geological event. In such scenarios, the aforementioned connectors are designed to guide damage in the framing members of the volumetric modules in order to mitigate the effects of external forces, reducing the likelihood of collapse of the structure but often requiring costly and impractical retrofitting programmes - or sometimes even demolition - as the only viable solution. Moreover, in the process of transferring forces induced by such events, parts of these previously proposed connectors (such as structural bolts, assembly pins, connecting plates, gusset plates or endplates, for example) can be distorted to such an extent that connector components can become jammed and further inhibit dismantling of the modular assemblies.

It is apparent, therefore, that it would be beneficial if a connector could be provided that enables the assembly and disassembly of buildings constructed from volumetric modules to be improved, whilst also providing improved ductility and energy dissipation. It would be particularly beneficial if that connector were to employ components that are easier to repair or replace, and which could contribute to the damage distribution mechanism of the building as a whole.

Aspects of the connector disclosed herein have been devised with the foregoing in mind.

One presently preferred aspect of this disclosure provides a connector for connecting volumetric modules of a modular building system, the connector comprising: a first plate that defines a first plate aperture; a second plate that defines a second plate aperture, and a resilient core that defines a resilient core aperture; wherein the first plate aperture, the second plate aperture and the resilient core aperture are arranged so that the respective apertures align when the resilient core is sandwiched between the first and second plates to thereby provide a channel through the first and second plates and the resilient core, said channel being sized to accommodate a fixing so that a structural member of a first volumetric module abutted against said first plate can be connected by means of said fixing to a structural member of a second volumetric module abutted against the second plate.

This arrangement provides a number of advantages. Firstly, as the core is resilient, the connector enhances energy dissipation in buildings constructed from a plurality of volumetric modules, particularly when such buildings are subject to meteorological or geological events, such as extreme weather conditions or earthquakes. Secondly, as the fixing extends through aligned apertures in the plates and core, the plates and core act to shield the fixing from the effects of fire and hence help reduce the amount of damage to the fixing in the event of a fire. Thirdly, as the connector only requires - in an envisaged implementation - a single fixing to couple adjacent volumetric modules, so the assembly and disassembly of buildings involving a plurality of such volumetric modules can be facilitated.

In a preferred implementation, the resilient core may be capable of resiliently deforming when a building in which the connector is used to couple adjacent volumetric modules together is exposed to external forces during a meteorological or geological event.

The resilient core may have a similar lateral cross-sectional shape to those of the first and second plates. The resilient core may be generally square in lateral crosssection. The resilient core may be generally circular in lateral cross-section. The circular resilient core may have a diameter that is approximately equal to the length of a side of the first or second plates.

The resilient core may be laminar. The laminar resilient core may comprise alternating layers of resilient elastomer, such as rubber, and reinforcing metal shims, for example of steel. The resilient core may comprise a laminated elastomeric bearing including one or more rubber layers reinforced with steel shims.

In one implementation, at least one of the first and/or second plates may comprise a plurality of lugs projecting from the plate in a direction away from the resilient core. The lugs may be configured to mate with co-operating recesses formed in a structural member of a volumetric module against which the plate abuts in use.

In an envisaged implementation, the first and second plates and the resilient core may each define a plurality of apertures, the plurality of first plate apertures aligning with the plurality of resilient core apertures and the plurality of second plate apertures to thereby provide a plurality of channels through the connector that are each sized to accommodate a fixing. In one arrangement, the first and second plates and the resilient core may each define a pair of apertures, the first plate apertures aligning with the resilient core apertures and the second plate apertures to form a pair of channels that are each sized to accommodate a fixing, the connector being configured to be suitable for coupling a first pair of adjacent volumetric modules to a second pair of volumetric modules stacked on the first pair. In another envisaged arrangement, the first and second plates and the resilient core may each define four apertures arranged at the corners of a square, the first plate apertures aligning with the resilient core apertures and the second plate apertures to form four channels that are each sized to accommodate a fixing, the connector being configured to be suitable for coupling a first set of four adjacent volumetric modules to a second set of four volumetric modules stacked on the first set.

Another aspect of this disclosure relates to a building comprising a plurality of interconnected volumetric modules, wherein at least a part of a first of said plurality of volumetric modules is connected to at least a part of a second of said plurality of volumetric modules by means of a connector of the type disclosed herein. Each volumetric module may comprise a plurality of structural members and a plurality of corner fittings, said structural members being coupled together at each corner of the volumetric module by means of a corner fitting.

A further aspect of this disclosure relates to a modular building comprising a plurality of volumetric modules stacked on top of one another, wherein the building comprises a connector of the type disclosed herein, the connector being arranged so that said first plate abuts against a corner fitting of a first volumetric module and said second plate abuts against a corner fitting of a second volumetric module stacked upon the first with the connector sandwiched therebetween, the first and second volumetric modules being coupled together by means of a fixing extending through the channel in the connector, the fixing being capable of being tightened to clamp the first plate against the corner fitting of the first volumetric module and the second plate against the corner fitting of the second volumetric module to thereby couple the first and second volumetric modules together. The fixing between the first and second volumetric modules may be releasable.

Other advantages and aspects of the connector disclosed herein will be apparent from the detailed description provided below.

Brief Description of the Drawings

The teachings of this disclosure, and arrangements embodying those teachings, will hereafter be described by way of illustrative example with reference to the accompanying drawings, in which:

Fig. 1 is a schematic perspective view of a volumetric module of a modular building system;

Fig. 2 is an enlarged perspective view of region A of Fig. 1;

Fig. 3 is a schematic perspective view of a connector that embodies the teachings of this disclosure;

Fig. 4 is a schematic perspective view of another connector that embodies the teachings of this disclosure;

Fig. 5 is an enlarged perspective view of a part of another volumetric module;

Fig. 6 is a schematic perspective view of another connector for use with the module of Fig. 5;

Fig. 7 is a schematic perspective view of yet another connector for use with the module of Fig. 5;

Fig. 8 is an exploded perspective view of part of two volumetric modules that are coupled to one another by means of a connector of the type depicted in Fig. 6;

Fig. 9 is a cross-sectional view through two identical volumetric modules that are coupled together by a connector of the type depicted in Fig. 6;

Fig. 10 is a cross-sectional view through two different volumetric modules that are coupled together by a connector of the type depicted in Fig. 6;

Fig. 11 is an exploded perspective view of another connector that can be employed to assemble four volumetric modules into a building that is one module wide, two modules long and two modules high;

Fig. 12 is a perspective view of another connector that has been employed to assemble four volumetric modules into a building that is two modules wide, two modules long and one module high; and

Fig. 13 is a schematic perspective view of four additional modules being added to the arrangement shown in Fig. 12 to form a building that is two modules long, two modules wide and two modules high.

Detailed Description

Fig. 1 is a schematic perspective view of a volumetric module 1 of a modular building system. The volumetric module 1 is typically made of a plurality of structural members, typically of steel, that are connected - typically by welding - to cast hollow cassettes (also typically of steel) at each corner of the modules, called corner fittings 3.

The structural members that form columns 5 of the module (i.e. those members that are typically substantially vertical in use) are typically made of hot-rolled hollow steel square sections members, and the structural members that form beams 7 of the module (i.e. those members that are typically substantially horizontal in use) are typically made of either hot-rolled hollow steel square- or rectangular-section members, parallel flange channel sections or other types of cold-formed steel sections. However, the connector disclosed herein is not limited for use only with beams of the foregoing type. The connector disclosed herein can be employed to couple modules having structural members of any cross-section, as the nature of the proposed connector is not affected by the geometrical details of the structural members.

Fig. 2 is an enlarged perspective view of region A of Fig. 1, showing an illustrative corner fitting 3. In this example, the corner fitting 3 comprises a hollow cast steel cube with access openings 9 formed in outwardly facing surfaces of the cube. A column 5 has been welded to a bottom face of the cube and beams 7 have been welded to inwardly facing faces of the cube. A top face 11 of the cube is provided with an aperture 13 for receiving a fixing.

Fig. 3 is a schematic perspective view of a connector 15 that embodies the teachings of this disclosure. The connector 15 comprises a first plate 17 and a second plate 19. In use, the first plate will be the uppermost plate and the second plate will be the lowermost. A resilient core 23 is sandwiched between the first and second plates 17, 19 and is operable to resiliently deform when exposed to external forces during a meteorological or geological event. The first plate 17 is provided with an aperture (or through-hole) 21 that aligns with corresponding apertures (not visible) in the resilient core 23 and the second plate 19. The aligned apertures in the first plate, second plate and core provide a channel through the connector for receiving a fixing.

In this implementation, the first and second plates, and the resilient core are each at least roughly the same size and shape as the top face 11 of the corner fitting 3 (which will, in turn, be roughly the same size and shape as a lower face of a second corner fitting (not shown) that the connector is to connect to the depicted corner fitting 3). In this instance, the first and second plates and the resilient core are square shaped.

Fig. 4 is a schematic perspective view of another connector 25 that embodies the teachings of this disclosure. This connector 25 differs from that depicted in Fig. 3 in that the resilient core 27 in this instance is generally circular and has a diameter that is approximately equal to the length of a side of the first and second plates.

In general terms it is preferred for the resilient core to fill as much of the volume between the first and second plates as possible, in order to smoothly transfer loading between connected volumetric modules and avoid forming additional stress points.

Fig. 5 is an enlarged perspective view of the corner fitting 3 of another volumetric module, and Figs. 6 and 7 are schematic perspective views of connectors 29, 31 for use with the module of Fig. 5. Elements of the connectors 29, 31 and the corner fitting 3 are similar to those of the connectors and corner fitting of Figs. 2, 3 and 4 and are designated as such by having the same reference numerals. For brevity, these features will not be described again.

The principal difference between the corner fitting of Fig. 5 and the corner fitting of Fig. 2 is that in the Fig. 5 fitting the top face 11 of the fitting includes a plurality of locating holes 33. In this particular example, the top face 11 includes four locating holes that are each generally square. In other implementations, a greater or lesser number of holes may be provided, and the holes may have a different shape.

The principal difference between the connectors of Figs. 6 and 7, vis a vis the connectors of Figs. 3 and 4, is that the first and second plates each include a plurality of locating lugs 35 (the lugs on the second plate being hidden from view). The lugs on the second plate are each shaped and arranged to locate in one of the locating holes in the top face of the corner fitting, and the lugs on the first plate are each shaped and arranged to locate in one of the locating holes on a bottom face of a corner fitting of a second volumetric module (not shown).

The co-operating locating holes and lugs function to ease the assembly process by facilitating alignment of the connector between two volumetric modules that are to be connected together. The holes and lugs also function to restrain lateral movement of one module relative to another in the event that the fixing coupling the modules together should fail during a meteorological or geological event.

Fig. 8 is an exploded perspective view of part of two volumetric modules that are coupled to one another by means of a connector 29 of the type depicted in Fig. 6. As shown the lugs projecting from the second plate (not visible) of the connector 29 mate with the locating holes in the top face 11 of the lower volumetric module corner fitting 3, and the lugs 35 projecting from the first plate of the connector 29 mate with co-operating locating holes (not visible) in the bottom face of the upper volumetric module corner fitting 3. Once the connector 29 is sandwiched between the upper and lower volumetric module corner fittings, a bolt 37 (introduce via the access opening) can be passed through an aperture in the bottom face of the upper volumetric module corner fitting, through the channel in the connector and through the aperture 13 in the top face 11 of the lower volumetric module corner fitting. Once inserted, a washer 39 and nut 41 can be introduced into the lower volumetric module corner fitting and engaged with the threaded end of the bolt 37 to securely connect the upper volumetric module to the lower volumetric module.

As aforementioned, since the fixing passes through the connector, the connector helps to shield the fixing from damage. It is also the case that by virtue of this arrangement it is possible to construct a building using only a single bolt or other fixing to join adjacent upper and lower pairs of corner fittings.

The bolt or other fixing is provided to secure the uplift (tension) resistance of the connection, while also resisting inter-storey drifts through a combined bending and shear action. In a preferred arrangement the bolt is aligned through a centreline of the columns, and this alignment reduces the occurrence of additional bending moments in the connection caused by eccentric loads while also promoting the scalability and flexibility of the design by keeping a simple and symmetric configuration. Moreover, this configuration provides that that load paths extend through the rigid corners of the modules and placing the bolt or other fixing inside the corner fittings provides an additional layer of protection from fire or thermal expansion. In an envisaged implementation, the bolts or other fixings are made of standard high-strength steel classes or austenitic shape-memory alloys such as Nickel-Titanium or other such alloys with similar properties.

Referring now to Fig. 9, there is depicted a cross-sectional view through two identical volumetric modules that are coupled together by a connector 29 of the type depicted in Fig. 6. In this instance the two volumetric modules are coupled together by means of a rod 43 that is threaded at either end, and nuts screwed onto each end of the rod.

Of particular note in Fig. 9 is the laminar nature of the resilient core 23. As depicted, the resilient core 23 is comprised of alternating layers of resilient elastomer 45 (e.g. rubber) and reinforcing metal shims 47 (e.g. of steel). The resilient core is effectively a laminated elastomeric bearing made of a single rubber compound layer or multiple rubber compound layers reinforced with steel shims. The connector has two main functions and can be regarded both as a bearing and as a dissipative device. The connector provides even and continuous vertical load paths between modules, being capable of withstanding large compressive stresses while it alleviates the high-stress force-transfer zones at the corners of modules by accommodating inter-storey shear forces and lateral drifts.

In the arrangements described above the fittings are integrated into the corners of the volumetric modular units but it will be apparent that such fittings may also be placed at intermediate locations where additional vertical members are required to improve the rigidity of the volumetric module.

In a preferred arrangement the plan dimensions of the corner fitting match those of the vertical member’s cross section, resulting in a flush alignment of the outer faces. The first and second plates also match adjacent surfaces of the corner fittings, facilitating alignment.

In a building constructed from these volumetric modules, individual modular units are connected at each level by means of connectors of the type described herein installed between corner fittings. The vertical structural bolts or other fixings are then tightened to a required level of pretension, finalising the connection between modules. Tensioning the bolt nuts is done from within the already installed lower-level modules, through specially cut out compartments through the floor or walls or from outside the modules for corner and external side connections. For internal joints, corner fittings may be extended to integrate access holes above the floor beams or below the ceiling beams, depending on the location of the corner fitting within the volumetric module. To accelerate on-site installation sequences, the intermediate connectors for corner joints can be pre-mounted in shop on top of modules, while bolts can be pre-installed in the bottom corner fittings and kept in vertical position by gravity during module lifting and installation.

In general terms, the connector comprises a laminated elastomeric bearing (LEB) for installation between the corner fittings of modules and a long hex bolt or other fixing running through the centreline of the corner SHS (square hollow section) posts. The main advantages of the proposed inter-module connection system are threefold: (1) deconstruction-friendly design through demountable fastener, (2) improved damage control through resilient LEB connector, and (3) improved energy dissipation and, optionally, re-centring by virtue of the employment of a super-elastic shape-memory alloy for the fastener.

In a particular example, corner supported modules made of hot-rolled structural steel profiles are considered for the application of the proposed connection. Corner posts and ceiling beams are made of SHS profiles, while floor beams are made of RHS (rectangular hollow section) profiles. Corner fittings made of structural steel are located at the corners of modules, to improve the rigidity of the volumetric unit and to help accommodate constructional tolerances by enhancing the regularity of the structural grid. Intra-connections are done offsite by welding the framing elements to the corner fittings during module manufacturing.

The introduction of a bearing component (LEB) between the volumetric units seeks to provide even and continuous vertical load paths between modules, improving the redundancy of the assembly in case of unpredicted beam-column joint design malfunctions. The LEB acts like a resilient spring with low lateral stiffness, capable of developing large elastic shear strains without suffering permanent damage. The large inter-storey drifts are controlled by the combined shear and bending of the structural bolt running through the LEB, which provides the main resistance of the connection to horizontal shear. Besides, additional mechanisms of energy dissipation can be integrated in the configuration of the joint by virtue of the space between modules. While this connection decouples the vertical diaphragm, it enhances the continuity of the horizontal diaphragm as the floor plates act together being all clasped at the corners to the LEB parts. Avoiding contact between modules through the LEB aims to reduce the damage induced in the framing elements of modules by lateral loads. The gap created by this part separates the floor and ceiling beams, preventing damage in these parts from combined action under compressive loads. In this configuration, the beams are designed separately for ULS (flexural bending) and SLS (deflection), which enhances the structural integrity of modules, offering good flexibility and adaptability opportunities if architectural layout changes are desired during the life cycle of the structure. Moreover, the gap created between ceiling and floor beams can be used to house building services while the air barrier provides additional fire resistance and improves the acoustic performance of the modular structure.

In one example, the resilient core is made of several layers of elastomeric material (vulcanized natural rubber or polychloroprene) bonded to rigid steel shims with suitable adhesives. The adhesive bond between the elastomeric layers and steel shims is done during the vulcanization process and is stronger than the rubber itself assuming no manufacturing errors occur. The rigid steel shims are introduced to enhance the compressive axial load bearing capacity of the connectors, as these are placed at the corners of modules and have to resist significant gravitational loads without significant shortening or developing large compressive strains. The first and second plates of the connectors are thicker to ensure the strength of the connection to the upper and lower corner fittings. Four shear keys (the aforementioned lugs 35) are placed on both first and second plates of the connector towards the corners to transfer horizontal shear forces between upper and lower modules. Matching holes are cut through the lower plate of the upper corner fitting and upper plate of the lower corner fitting to permit plugging-in the connector before installing the bolt.

There are multiple ways of installing the connector during site assembly of buildings constructed from a plurality of volumetric modules. To facilitate the speed of the on-site assembly process the connectors and bolts can be pre-mounted in shop on top of modules. After transportation to site, the nuts of the pre-attached bolts are unfastened to allow the newly arrived modules to be plugged into the connectors, after which the nuts are fastened through the access holes in the corner fittings, securing the newly installed modules. For corner and external joints, access to tighten the bolts can easily be provided through the holes in either of the upper of lower corner fittings, depending on the chosen method of assembly. For an internal joint, access openings are required to be cut in the steel wall of column sections. Alternatively, the floor or ceiling beams could be welded directly to the corner posts, leaving the sides of the corner fittings clear of obstacles or PFC beam sections could be adopted, which would provide access for engagement. In a preferred arrangement the lugs on the plates have filleted edges to allow easy sliding, thus serving as guiding elements which facilitate alignment during installation. The holes in the corner fittings can also be used to attach the hooks of a lifting frame.

Fig. 10 is a schematic cross-sectional view through a connector provided between a lower SHS corner fitting and an upper RHS corner fitting. Fig. 11 is a schematic representation of a connector that is configured to couple a lower pair of volumetric modules that have been placed back to back (or side to side) to an upper pair of modules that are similarly arranged. As with the previously described arrangement, a single bolt connects each upper and lower pair of corner fittings.

Fig. 12 is a schematic representation of a connector that is configured to couple four lower volumetric modules that have been abutted to an upper set of four modules that are similarly arranged. As with the previously described arrangement, a single bolt connects each upper and lower pair of corner fittings. Figure 12 shows the lower four volumetric modules coupled together by means of the connector, and Fig. 13 shows the upper four modules being added. Of particular note in Figs. 12 and 13 are the enlarged access holes 49 that are provided to enable bolts or other fixings in internal building joints to be tightened.

It will be appreciated that whilst various aspects and embodiments have heretofore been described, the scope of this disclosure is not limited to the particular arrangements set out herein and instead extends to encompass all arrangements, and modifications and alterations thereto, which fall within the spirit and scope of the disclosure. For example, whilst in the preferred arrangement lugs on the connector mate with holes in the corner fittings of adjacent volumetric modules, it will be apparent to persons of skill in the art that the corner fittings could instead be provided with lugs for mating with holes in the connector. It is also the case that the connector and corner fittings could be provided with complementary patterns of holes and lugs. It is also envisaged for only one of the first and second plates to be configured to mate with the corner fitting of a volumetric module.

In addition to the foregoing, it should also be noted that whilst particular combinations of features are described herein, the scope of the present disclosure is not limited to the particular combinations disclosed, but instead extends to encompass any combination of features herein disclosed.

Finally, it should be noted that any element in a claim or invention summary that does not explicitly state "means for" performing a specified function, or "steps for" performing a specific function, is not to be interpreted as a "means" or "step" clause as specified in 35 U.S.C. Sec. 112, par. 6. In particular, the use of "step of" in the claims appended hereto is not intended to invoke the provisions of 35 U.S.C. Sec. 112, par. 6.