GB2508801A

GB2508801A - Tube interlock

Info

Publication number: GB2508801A
Application number: GB1219045.0A
Authority: GB
Inventors: Domenic Tedesco; Donato Tedesco; Joseph Pacitti
Original assignee: SCOTIA MODULAR Ltd
Current assignee: SCOTIA MODULAR Ltd
Priority date: 2012-10-23
Filing date: 2012-10-23
Publication date: 2014-06-18
Also published as: GB201219045D0

Abstract

A tube interlock 1 comprises a locking component 2 attached to a body 8. The locking component extends into the tube and is locked to an internal surface of the tube. A second locking component 4 coupled to the first via the body may extend into a second tube. The locking components may comprise locating and self-centring portions. The locking components may provide a friction fit with the internal surface of the tube via a cap. The interlock may also be fixed to the internal surface of the tube by a matrix such as concrete set inside the tubes. Also claimed are a method of assembling a modular building structure using an interlock and a kit of parts.

Description

1 MODULAR BUILDING STRUCTURE AND METHOD

3 Field of the invention

The invention relates to a modular building structure, a method of assembling a 6 modular building structure, an interlock and a kit of parts for assembling a modular 7 building structure.

9 Background to the invention

11 It is notoriously difficult for buildings to retain their structural integrity in the event of 12 earthquakes or other major seismic activity occurring in their vicinity. In particular, 13 torsion, deflection and compression forces resulting from seismic activity can cause 14 separation or breakage of tubular components (such as hollow steel beams or frames comprising hollow steel beams) within modular building structures. It is therefore 16 desirable to improve the way in modular building structures comprising tubular 17 components are assembled in order to improve their resistance to these forces so as 18 to improve the resistance of buildings to such events. This is particularly important 19 for buildings in geographical areas where seismic activity and earthquakes are relatively commonplace (e.g. near fault lines).

22 It is also desirable for modular building structures comprising tubular components to 23 be made more compact without compromising their strength or indeed their 1 resistance to torsional, compression or deflection forces (whether or not they are 2 located in areas of significant seismic activity).

4 In addition, existing on-site assembly processes for connecting modular building components can be complex and inaccurate alignment can occur between the 6 components. Such processes can compromise the integrity of modular building 7 structures because inaccurate alignment can create weak points in the structure.

9 The invention relates to a modular building structure comprising at least one tube, the modular building structure having a greater resistance to torsion forces (and in some 11 embodiments also compression and deflection forces) than known such structures 12 without requiring a corresponding increase to the overall size of the structure. The 13 invention also relates to a method of assembling a modular building structure. The 14 said method is simple and repeatable, leading to the assembly of consistently high integrity structures.

17 Summary of the invention

19 A first aspect of the invention provides a modular building structure comprising: a building portion comprising a tube; an interlock comprising a locking component 21 extending from a body, the locking component of the interlock extending into the tube 22 of the building portion; and a locking means (such as a locking mechanism) locking 23 the locking component to an internal surface of the tube of the building portion.

Because the locking means locks the locking component to an internal surface of the 26 tube of the building portion, decoupling of the interlock and the building component is 27 inhibited and the resistance of the interlock to rotation relative to the tube of the 28 building portion is increased. This improves the torsional resistance of the modular 29 building structure and allows the modular building structure (and a building comprising the modular building structure) to better resist major shocks such as 31 earthquakes or other seismic activity.

33 Typically, the body does not extend into the tube of the building portion.

The interlock may be made of any suitable material(s), such as a metallic element or 36 alloy (e.g. steel).

1 The locking means locks the (first) locking component of the interlock to the internal 2 surface of the tube of the (first) building portion so as to inhibit rotation of the interlock 3 relative to the tube. The locking means typically provides a more secure lock than, 4 for example, a typical interference fit. Typically, the locking means directly couples the (first) locking component to the internal surface of the tube of the (first) building 6 portion. Typically the (first) locking component comprises a proximal end connected 7 to (or integrally formed with) the body and a distal end opposite the proximal end, and 8 the locking means locks at least an intermediate portion of the (first) locking 9 component between its proximal and distal ends to the internal surface of the tube of the first building portion. In some embodiments, the (first) locking component 11 comprises a proximal end connected to (or integrally formed with) the body and a 12 distal end opposite the proximal end, and the locking means locks at least the distal 13 end of the (first) locking component to the internal surface of the tube of the first 14 building portion. In some embodiments, the (first) locking component comprises a locked portion locked to the internal surface of the tube of the first building portion, 16 the distance between the said locked portion and the body in a direction parallel to 17 the longitudinal axis of the (first) locking component being greater than the maximum 18 width of the (first) locking component in a direction perpendicular to the longitudinal 19 axis of the (first) locking component.

21 In some embodiments, the locking component is a first locking component and the 22 building portion is a first building portion, the interlock comprising a second locking 23 component coupled to the first locking component by the body, and the second 24 locking component being coupled to a second building portion.

26 Typically the first and second building portions are constructed separately and the 27 interlock is used to join them together, typically for the construction of multi-storey 28 buildings. Typically the first and second building portions are discrete building 29 portions, such as two discrete building modules. For example, the first and second building portions may be modular frames which one or both of which may (but do not 31 necessarily) comprise a plurality of interconnected steel beams. In other 32 embodiments, the first and second building portions comprise steel beams.

34 In another embodiment, the second building portion may comprise or be coupled to a building foundation. In this case, the second locking component of the interlock may 36 be coupled (or directly connected) to the second building portion by one or more bolts 37 (e.g. the bolts may extend between the second locking component and the second 1 building portion). The second locking component may comprise a plate. In one 2 embodiment, the second locking component forms part of the body of the interlock.

4 In some embodiments, the second building portion comprises a tube, and the second locking component extends into the tube of the said second building portion. In this 6 case, the second locking component may be locked to the internal surface of the tube 7 by a second locking means (such as a second locking mechanism).

9 Typically, the body does not extend into either the tube of the (first) building portion (or the tube of the second building portion, where provided).

12 The body may form a bridge between the (e.g. tubes of the) first and second building 13 portions. The body may engage adjacent ends of (e.g. tubes of) the first and second 14 building portions to which the first and second locking components are locked/coupled.

17 Typically the or each of the said tube(s) comprise internal bore(s) in which the locking 18 component(s) are inserted. Typically, the or each of the said tubes comprises an 19 internal longitudinal bore extending along its length. Typically, the said internal surface to which the locking component is or the first and/or second locking 21 components are locked is an internal surface of a longitudinal wall of the said 22 (respective) longitudinal bore. Typically the said longitudinal bore(s) terminate in 23 apertures at opposite ends of the tubes.

Where first and second locking components are provided on the interlock and the first 26 and second building portions comprise tubes, the first locking component may be 27 inserted into an aperture at a first end of the tube of the first building portion and the 28 second locking component may be inserted into an aperture at a first end of the tube 29 of the second building portion adjacent to the said first end of the tube of the first building portion.

32 Where two locking components are provided, the first locking component may be 33 locked to the said internal surface of the tube of the first building portion by a first 34 locking means and the second locking component may be coupled directly to the second building portion by a second locking means (e.g. by bolts where the second 36 locking building portion comprises a building foundation or, where the second 37 building portion comprises a tube, by an expandable cap or set matrix (see below) 1 which locks the second locking component to an internal surface of the tube of the 2 second building portion). However, in other embodiments, the first locking 3 component may be locked to the said internal surface of the tube of the first building 4 portion, and the second locking component may not be coupled directly to the second building portion. In this case, the second locking component may be coupled 6 indirectly to the second building portion. For example, the first locking component of 7 a first interlock may be inserted into an end of a tube of the first building portion and 8 locked to an internal surface thereof by a first locking means, a second locking 9 component of the first interlock may be inserted into a first end of a tube of the second building portion, and a (or the) locking component of a second interlock may 11 be inserted into the second end of the said tube of the second building portion 12 opposite the first end and locked to an internal surface thereof by a second locking 13 means. The locking means locking the first locking component of the first interlock to 14 the tube of the first building portion and the locking component of the second interlock to the tube of the second building portion indirectly couple the second locking 16 component of the first interlock to the tube of the first building portion and help to 17 prevent relative rotation of the tubes of the first and second building portions and the 18 first and second interlocks. In addition, if the second building portion is stacked on 19 top of the first building portion, the weight of the second building portion (and any structure above the second building portion) helps to retain the second locking 21 component of the first interlock in the said first end of the tube of the second building 22 portion.

24 In one embodiment the body comprises a first side and a second side opposite the first side, the first locking component extending from the first side and the second 26 locking component extending from the second side. It will be understood that any 27 number (including zero, one or more, two or more, three or more and so on) of 28 locking components may extend from either side of the body depending on building 29 requirements.

31 Typically, the body comprises a plate. In one embodiment, the plate comprises a first 32 face and a second face opposite the first face, the first locking component extending 33 from the first face and the second locking component extending from the second 34 face. The plate may have a cross section perpendicular to the longitudinal axis of the locking component or the longitudinal axes of the first and/or second locking 36 components, the said cross section of the plate having a maximum width equal to the 37 maximum width of a cross section of (and therefore flush with) the locking component 1 or first and/or second locking components in a direction perpendicular to its or their 2 longitudinal axes. More typically, the said cross section of the plate has a greater 3 width than the maximum width of the cross section(s) of the or the first and/or second 4 locking components in a direction perpendicular to its or their longitudinal axes. The maximum width of the said cross section of the plate may be substantially equal to 6 (e.g. less than 20% greater than, more preferably less than 10% greater than, even 7 more preferably less than 5% greater than) an outer diameter (or maximum external 8 width of the cross section perpendicular to the longitudinal axis) of the said tube(s) of 9 the or the first and/or second building portions.

11 The first and second locking components may have a common longitudinal axis. This 12 ensures a linear load direction through the interlock.

14 The first and second locking components may be different from each other (e.g. they may have different sizes or shapes) in which case they can be used to join together 16 building portions having different properties. Alternatively, the first and second 17 locking components are substantially identical (e.g. they have substantially identical 18 sizes and shapes) in which case they can be used to join together building portions 19 having tubes with substantially similar shapes and sizes.

21 Typically, the length(s) of the (first) locking component or (particularly where both the 22 first and second locking components extend into respective tubes of the first and 23 second building portions) of the first and/or second locking components extending 24 inside their respective tubes is greater than a maximum internal width of a or the longitudinal bore of the tube (or at least the portion of the tube) into which the 26 respective locking component extends. Preferably, the length of each of the said 27 locking component(s) extending inside the respective tube(s) is greater than twice the 28 maximum internal width of a or the longitudinal bore of the tube (or at least the portion 29 of the tube) in which the respective locking component extends.

31 Typically, the locking means extends between (and typically engages) the (first) 32 locking component and the internal surface of the said tube of the first building 33 component. Typically the locking means extends from the (first) locking component 34 to the internal surface of the tube.

36 Typically, the locking means comprises a discrete component (i.e. discrete from the 37 (first) locking component).

2 The cross section(s) of the said tube(s) of the first (and optionally second) building 3 portions perpendicular to their longitudinal axes may be circular, but more preferably 4 the said cross section(s) of the said tube(s) have angular (typically quadrilateral) edges. In one embodiment, the said cross section(s) of the said tube(s) are square 6 or rectangular in shape.

8 The (first) locking component is typically a male locking component. The second 9 locking component, where provided, may also be a male locking component.

11 The (first) locking component or the first and/or second locking components may be 12 connected to or integrally formed with the body.

14 Preferably the (first) locking component or the first and/or second locking components comprise locating portions.

17 Typically the locating portion of the (first) locking component or the first and/or 18 second locking components comprise opposite first and second faces spaced apart 19 by a distance substantially equal to a maximum internal width of (at least the portion of) the respective tube in which the said locking component or the respective first 21 and/or second locking components extend. Preferably, the locating portions of the 22 said locking component(s) provide the said locking coniponent(s) with an interference 23 fit in the respective tube(s). By providing the said locking component(s) with locating 24 portions, feedback can be provided (e.g. to a builder) that the said locking component(s) have been accurately and fully installed in the (respective) tube(s).

27 The locating portions (where provided) of the (first) locking component are typically 28 different from the locking means locking the (first) locking component to the internal 29 surface of the said tube of the first building portion.

31 Typically the locating portion(s) of the locking component(s) has a cross section 32 perpendicular to the longitudinal axis of the said locking component, the said cross 33 section of the locking component having a shape conforming to a cross section of an 34 internal longitudinal bore of the tube into which it extends, the said cross section of the said internal bore being perpendicular to a longitudinal axis of the said internal 36 bore.

1 By providing the said cross section of the (first and/or second) locking component(s) 2 with a shape which conforms to the said cross section of the said internal bore of the 3 tube into which it extends, the torsional resistance of the interlock may be increased 4 further. This is because it may be more difficult for a locking component conforming to the shape of the bore to rotate relative to the said tube in which it is inserted than if 6 they had different shapes.

8 Typically, the said cross sections of the locking components and the bores have 9 angled perimeters. The angled perimeters of the said cross sections make it even more difficult for the interlock and the tube to rotate relative to each other.

12 Preferably the (first) locking component comprises a first substantially planar face on 13 a first plane and a second substantially planar face lying on a second plane 14 substantially orthogonal to the first plane, the said cross section of the (first) locking component being taken through the first and second faces.

17 The said cross section of the (first) locking component is typically perpendicular to the 18 said first and second faces.

The locking component or the first and/or second locking components may comprise 21 self-centring portions. The self-centring portions help to ensure accurate alignment of 22 the locking component(s) in the tube(s).

24 Self-centring portions aid insertion of the said locking component(s) into the respective tube(s) of the building portions in which it (they) is (are) inserted.

26 Typically, the self-centring portion of each said locking component comprises a cross 27 section perpendicular to the longitudinal axis of the said component, the said cross 28 section being tapered down in width from a proximal end of the self-centring portion 29 adjacent (and typically coupled) to the body to a distal end of the self-centring portion (the distal end is typically more remote to the body than the proximal end is to the 31 body, and the distal end is typically provided opposite the proximal end). Typically, 32 the self-centring portion of each said locking component has a cross section 33 perpendicular to a longitudinal axis of the said locking component, the said cross 34 section tapering down in width (typically in two orthogonal dimensions) between the proximal end and the distal end (and typically from the proximal end to the distal 36 end).

1 Typically, the self-centring portions of the said locking component(s) is(are) coupled 2 to their locating portions (where provided). In one embodiment, where a locking 3 component has a locating portion and a self-centring portion, the proximal end of the 4 self-centring portion comprises the locating portion and a cross section through the distal end of the self-centring portion perpendicular to the longitudinal axis of the said 6 locking component has a lower width (typically in two orthogonal dimensions) than a 7 corresponding cross section through the proximal end of the self-centring portion 8 perpendicular to the longitudinal axis of the said locking component.

In some embodiments, the said cross section of the distal end is provided with a 11 different shape to the said cross section of the proximal end. This may be, for 12 example, because of one or more chamfered edges on the external surfaces of the 13 locking components adjacent their distal ends.

Typically the self-centring portion of the said locking component(s) reduces in width 16 (typically in first and second orthogonal dimensions) with increasing distance from the 17 body.

19 The locking means may provide a frictional lock between the (first) locking component and the internal surface of the said tube.

22 In some embodiments the locking means comprises a cap fitted over a distal end of 23 the (first) locking component.

Preferably the cap is an expandable cap which has been fitted tightly to the said 26 distal end of the (first) locking component.

28 Typically a bore extends through the (first) locking component. Where first and 29 second locking components are provided, a bore typically extends through the second locking component.

32 The bores extending through the first and second locking components may be co- 33 axial and in communication with each other.

Typically, when the locking means comprises a cap fitted over a distal end of the 36 (first) locking component, a bore extends through the cap. Typically the bore which 37 extends through the cap is co-axial and in communication with the bores extending 1 through the locking component or the bores extending through the first and/or second 2 locking components.

4 Typically, a bore extends through the body. Typically, the bore extending through the body is also co-axial and in communication with the bores extending through the 6 locking component, or the first and/or second locking components, and the cap.

8 Preferably a rod is provided which extends through the bores extending through the 9 first and second locking components, the cap and the body. Typically the rod also extends through the said tubes of the first and second building portions.

12 The rod acts as an assembly aid for inserting the locking component or the first 13 and/or second locking components into the said tubes. The rod also increases the 14 stiffness and the strength of the modular building assembly. The external surface of the rod may be threaded. In this case, a tightening nut having an internal thread 16 compatible with the thread on the external surface of the rod can be screwed onto the 17 rod over the cap. In this case, the tightening nut can be tightened onto the cap so 18 that the cap expands to engage the internal surface of the said tube, thereby 19 frictionally locking the cap (and the (first) locking component) against the internal surface of the said tube.

22 In one embodiment, the cap comprises two or more wedges coupled together and 23 shaped to comply with a or the tapered self-centring portion of the first locking 24 component.

26 The cap preferably has a cross section perpendicular to the longitudinal axis of the 27 said (first) locking component which conforms to a cross section perpendicular to the 28 longitudinal axis of the said locking component of an internal longitudinal bore of the 29 tube in which it is positioned.

31 By providing the said cross section of the cap with a shape which conforms to the 32 said cross section of the said internal bore of the tube in which it is positioned, the 33 torsional resistance of the interlock is increased further. This is because it is more 34 difficult for a cap conforming to the shape of the bore to rotate relative to the said tube.

1 Typically, the said cross sections of the cap and the bores have angled perimeters.

2 The angled perimeters of the said cross sections make it more difficult for the cap and 3 the tube to rotate relative to each other.

Preferably the cap comprises a first face lying on a first plane and a second face lying 6 on a second plane substantially orthogonal to the first plane, the said cross section of 7 the cap being taken through the first and second faces.

9 The locking means (mechanism) may comprise a matrix (such as 070 or C85 grade concrete) set (e.g. thermoset or cured) to lock the first locking component against the 11 said internal surface of the tube of the first building portion. The matrix may comprise 12 one or more additives. In one embodiment, the matrix may comprise carbon or glass 13 fibres. The matrix may be a polymer modified matrix. The matrix may comprise 14 Fosroc Conbextra GB grout. The material composition of the matrix may be "tuned" (varied) for particular building requirements (e.g. required torsion, compression and 16 deflection resistances), to withstand earthquakes of particular magnitudes and/or to 17 set in a particular time in particular environmental conditions (e.g. temperatures).

18 The material composition of the matrix may also be adapted (e.g. by adding one or 19 more acoustic dampening additives thereto) to increase the sound absorption properties of the structure. One or more acoustic dampening washers may also be 21 added to the tube(s) to increase the sound absorption properties of the structure.

23 As well as providing a mechanism for locking the locking component to the said 24 internal surface of the said tube, the matrix also fills at least part of the tube thereby improving the compression and deflection resistance of the tube, and thus the 26 building assembly as a whole. In one embodiment, the matrix partially fills the said 27 tube. However, in another embodiment, the matrix substantially fills the said tube. In 28 the latter embodiment in particular, the compression and deflection resistance of the 29 tube is increased significantly.

31 In some embodiments, the tube of the first building portion has a first end and a 32 second end, the (first) locking component being inserted into an aperture provided at 33 the first end, and a washer located inside the tube of the first building portion at an 34 intermediate position along its length between the body of the interlock and the said second end. Preferably the washer is located between a distal end of the (first) 36 locking component and the second end.

1 The washer typically has a width substantially equal to the internal diameter of the 2 tube of the first building portion. The washer is typically coupled to the internal 3 surface of the tube of the first building portion by an interference fit. In one 4 embodiment, the washer is retained in the tube by one or more nuts threadably engaging a or the rod which extends through the washer and the first locking 6 component. Typically the washer is a separate component from the tube but the 7 washer may alternatively be integrally formed with the tube. The washer may, for 8 example, be made from a polymer such as polystyrene.

The washer blocks the flow of unset matrix during installation of the interlock in the 11 tube of the first building portion. This helps to retain the unset matrix in the portion of 12 the tube occupied by the (first) locking component when it is inserted into the first end 13 of the tube. Thus, when the matrix is set, the matrix hardens to lock the first locking 14 component against the said internal surface of the said tube.

16 In embodiments where the matrix substantially fills the tube, the washer is typically 17 omitted because it is not necessary to block the flow of unset matrix during 18 installation of the interlock. However, a washer may be temporarily fitted at one end 19 of the tube during installation of the interlock in order to prevent unset matrix from leaking out of the tube before locking components are inserted into the ends of the 21 tube.

23 The locking component or the first and/or second locking components may comprise 24 external faces having one or more ridges extending therefrom.

26 The one or more ridges increase the surface area of the external faces of the said 27 locking component(s), thereby increasing the surface area of the locking 28 component(s) to which the set matrix can bond. This increases the strength of the 29 locking action provided by the locking means against the internal surface of the said tube.

32 The external faces of the said locking components may comprise one or more 33 serrations, typically between adjacent pairs of ridges.

In embodiments where the said locking component(s) comprise tapered self-centring 36 portions, typically the said external faces of the locking components comprise one or 37 more external faces of the tapered self-centring portions.

2 Typically, the one or more ridges extend from external faces of the locking 3 components at an intermediate portion of the locking components between their 4 proximal ends (adjacent to the body) and their distal ends (remote from the body).

6 As explained above, only the (first) locking component may be locked to the internal 7 wall of a tube of a first building component, or the first locking component may be 8 locked to the internal wall of a tube of a first building component and the second 9 locking component may also be locked to the internal wall of a tube of a second building component. Accordingly, although some features of the locking means are 11 discussed above with respect to the lock between the (first) locking component and 12 the internal wall of the tube of the first building portion, it will be understood that these 13 features are equally applicable to (where provided) a lock between a second locking 14 component and the internal wall of the tube of a second building portion.

16 The invention also envisages a modular building structure comprising a plurality of 17 vertically stacked building components each comprising a tube substantially filled 18 with a set matrix, the said tubes being vertically stacked. Typically, each vertically 19 adjacent pair of tubes is interconnected by an interlock comprising a first locking component extending from a first side of a body into a first tube of the said pair, and a 21 second locking component extending from a second side of the body opposite the 22 first side into a second tube of the said pair. At least one of the locking components 23 of each interlock may be locked to an internal surface of the tube into which it extends 24 by a respective locking means. The body of each interlock extending between adjacent pairs of tubes acts as a bridge between the tubes of the said pair. Thus the 26 modular building structure can be provided with one or more integral vertical columns 27 having strong torsion, deflection and compression resistances compared to existing 28 modular building technologies. It will be understood that the interlocks and 29 substantially filled tubes ensure that there are substantially no discontinuities in load path through the structure, thus providing no significant weak points" in the columns.

32 Additionally or alternatively a capping interlock may be provided to close a top end of 33 the uppermost tube in the or each stack (or, if there is only one tube, in that tube), the 34 said capping interlock comprising a body and a locking component extending from the body into an aperture in the top end of the said (uppermost) tube, the body 36 typically engaging the (typically outer surface of the) top end of the tube (and typically 37 remaining outside of the tube). The locking component is typically locked to an 1 internal surface of the said tube by a locking means, e.g. by an expandable cap or a 2 hardened matrix extending between the locking component and the said internal 3 surface of the tube. Preferably, a hardened matrix substantially fills the tube.

A base interlock may additionally or alternatively be provided at the bottom end of the 6 lowermost tube in the or each stack (or if only one tube is provided, of that tube). The 7 base interlock may comprise a first locking component extending from a first side of a 8 body and extending into the lowermost end of the tube and being locked to the 9 internal surface thereof by a locking means, and a second locking component (which may for example comprise a plate) extending from (or even being) a second side of 11 the body opposite the first side and being locked to a foundation (or a component 12 coupled to the foundation) of the modular building structure. Preferably, a hardened 13 matrix substantially fills the tube.

Locking the interlock, capping interlock or base interlock to the internal surface of the 16 tube into which it extends increases the resistance of the modular building structure 17 to torsion loads significantly compared to existing modular building technologies.

18 Substantially filling the tubes with (hardened) matrix also significantly improves the 19 resistance of the modular building structure to compression and deflection loads.

21 The body of the base interlock may comprise a seismic dampener providing a 22 discontinuity in the resonance frequency of a path through the modular building 23 structure.

A second aspect of the invention comprises a method of assembling a modular 26 building structure, the method comprising: inserting a locking component of an 27 interlock into a tube of a building portion, the locking component extending from a 28 body of the interlock; and locking the locking component to an internal surface of the 29 tube of the building portion.

31 By locking the locking component to an internal surface of the tube of the building 32 portion, decoupling of the interlock and the building portion is inhibited and the 33 resistance of the interlock to rotation relative to the tube of the building portion is 34 increased. This improves the torsional resistance of the building structure, increasing its ability to retain its structural integrity in the event of a major shock such as an 36 earthquake or other seismic activity.

1 Typically, the building portion is a first building portion and the locking component of 2 the interlock is a first locking component, the method further comprising (e.g. directly 3 or indirectly) coupling a second locking component of the interlock to a second 4 building portion, the second locking component being coupled to the first locking component by the body.

7 In one embodiment, the second building portion may comprise or be coupled to a 8 building foundation. In this case, the method may comprise coupling (e.g. directly 9 connecting) the second locking component of the interlock to the second building portion by one or more bolts. The second locking component may comprise a plate.

11 In one embodiment, the second locking component forms the or part of the body.

13 In some embodiments, the second building portion comprises a tube, and the method 14 further comprises inserting the second locking component into the tube of the said second building portion. The method may further comprise locking the second 16 locking component to an internal surface of the tube of the second building portion.

18 Typically, the body is not inserted into the tube of the building portion or where first 19 and second building portions comprising tubes are provided, the first building portion or the tube of the second building portion.

22 The method may comprise forming a bridge using the body between the tubes of the 23 first and second building portions. The method may further comprise engaging the 24 body with adjacent ends of the tubes of the first and second building portions into which the first and second locking components extend.

27 Typically the tube(s) comprise internal bores in which the locking component or the 28 first and/or second locking components are inserted. Typically, the or each of the 29 tubes comprises an internal longitudinal bore extending along its length. Typically, the said internal surface to which the first locking component is locked is an internal 31 surface of a longitudinal wall of the said longitudinal bore into which it extends.

32 Typically the longitudinal bores terminate in apertures at opposite ends of the tubes.

34 Where first and second locking components are provided on the interlock and the first and second building portions comprise tubes, the method may comprise inserting the 36 first locking component into an aperture at a first end of the tube of the first building 1 portion and inserting the second locking component into an aperture at a first end of 2 the tube of the second building portion.

4 Where two locking components are provided, the method may comprise locking the first locking component to the said internal surface of the tube of the first building 6 portion and directly coupling the second locking component to the second building 7 portion (e.g. by bolts where the second locking building portion comprises a building 8 foundation or, where the second building portion comprises a tube, by an expandable 9 cap or set matrix which locks the second locking component to an internal surface of the tube of the second building portion). However, in other embodiments, the method 11 may comprise locking the first locking component to the said internal surface of the 12 tube of the first building portion, and not directly coupling the second locking 13 component to the internal surface of the tube of the second building portion. In this 14 case, the method may comprise coupling the second locking component indirectly to the second building portion. For example, the method may comprise inserting the 16 first locking component of a first interlock into an end of the tube of the first building 17 portion and locking the said first locking component to an internal surface of the said 18 tube, inserting a second locking component of the first interlock into a first end of the 19 tube of the second building portion (and not typically directly locking the second locking component to the internal surface of the tube of the second building portion), 21 and inserting a (or the) locking component of a second interlock into the second end 22 of the tube of the second building portion opposite the first end and locking the said 23 locking component of the second interlock to an internal surface of the tube of the 24 second building portion. The first locking component the first interlock locked to the tube of the first building portion and the locking component of the second interlock 26 locked to the tube of the second building portion indirectly couple the second locking 27 component of the first interlock to the tube of the first building portion and help to 28 prevent relative rotation of the tubes of the first and second building portions and the 29 first and second interlocks. In addition, if the second building portion is stacked on top of the first building portion, the weight of the second building portion (and any 31 structure above the second building portion) helps to retain the second locking 32 component of the first interlock in the said first end of the tube of the second building 33 portion. Accordingly, the method may comprise stacking the second building portion 34 on top of the first building portion such that the tube of the second building portion is vertically adjacent the tube of the first building portion.

1 In one embodiment the body comprises a first side and a second side opposite the 2 first side, the first locking component extending from the first side and the second 3 locking component extending from the second side. It will be understood that any 4 number (including zero, one or more, two or more, three or more and so on) of locking components may extend from either side of the body depending on building 6 requirements.

8 Typically, the locking means extends between the first locking component and the 9 internal surface of the said tube of the first building component.

11 Typically, the locking means comprises a discrete component (i.e. discrete from the 12 first locking component).

14 The method may further comprise locating the (first) locking component of the interlock in the tube of the first building portion before locking the first locking 16 component to the said internal surface of the said tube.

18 Typically, the or each locking component has a locating portion having a cross 19 section perpendicular to the longitudinal axis of the said locking component, the said cross section of the locking component having a shape conforming to a cross section 21 of an internal longitudinal bore of the tube into which it extends, the said cross section 22 of the said internal bore being perpendicular to a longitudinal axis of the said internal 23 bore.

By providing the said cross section of the or each locking component with a shape 26 which conforms to the said cross section of the said internal bore of the tube into 27 which it extends, the torsional resistance of the interlock is increased further. This is 28 because it may be more difficult for a locking component conforming to the shape of 29 the bore to rotate relative to the said tube than if they had different shapes.

31 Typically, the said cross sections of the locking components and the bores have 32 angled perimeters. The angled perimeters of the said cross sections make it more 33 difficult for the interlock and the tube to rotate relative to each other.

Preferably, the or the first and/or second locking component comprise a first 36 substantially planar face on a first plane and a second substantially planar face lying 1 on a second plane substantially orthogonal to the first plane, the said cross section of 2 the said locking component being taken through the first and second faces.

4 The said cross section of the said locking component is typically perpendicular to the said first and second faces.

7 The locating portion of the (first) locking component is typically different from the 8 locking means locking the first locking component to the internal surface of the said 9 tube of the first building portion.

11 The method may further comprise guiding the (first) locking component into the said 12 tube of the (first) building portion by a self-centring portion of the (first) locking 13 component before locking the (first) locking component to the said internal surface of 14 the said tube.

16 Typically, where the locking component is located in the said tube, the guiding/self- 17 centring step is performed before the locating step.

19 The self-centring portion of the first locking component thus aids insertion of the locking component into the tube. Typically, the self-centring portions are tapered 21 down in width (typically in two orthogonal dimensions) between a proximal end of the 22 locking component adjacent the body and a distal end (typically opposite the proximal 23 end) of the locking component.

Typically, the self-centring portion of the first locking component is coupled to its 26 locating portion (where provided). In one embodiment, where the first locking 27 component has a locating portion, a proximal end of the self-centring portion 28 comprises the locating portion and a distal end of the self-centring portion has a cross 29 section perpendicular to its longitudinal axis having a width less (typically in two orthogonal dimensions) than the proximal end.

32 Typically the self-centring portion of the first locking component reduces in thickness 33 (typically in first and second orthogonal dimensions) with increasing distance from the 34 body.

36 It will be understood that, where provided, the second locking component may have 37 identical locating and/or self-centring portions and similar method steps may be 1 employed to insert the second locking component into a tube (where provided) of the 2 second building component.

4 The second locking component may be substantially identical to the first locking component.

7 In some embodiments the method may comprise frictionally locking the first locking 8 component to the internal surface of the said tube.

In some embodiments, the method may further comprise fitting an expandable cap 11 over a distal end of the first locking component and tightening the cap against the 12 said distal end so that one or more dimensions of the cap expands to lock the first 13 locking component to the said internal surface of the said tube.

The step of tightening the cap against the said distal end may comprise screwing a 16 tightening nut against the expandable cap, the nut being threadably coupled to a rod 17 passing through the cap and the first locking component.

19 The method may further comprise engaging a locating portion of the first locking component with the internal surface of the tube of the first building portion.

22 In some embodiments, the method may further comprise: injecting (or introducing) a 23 flowable matrix into the tube of the first building portion before inserting the first 24 locking component into the said tube; inserting the first locking component into the said tube containing the flowable matrix; and setting the flowable matrix, thereby 26 hardening the flowable matrix to lock the first locking component against the said 27 internal surface of the said tube.

29 As well as providing a mechanism for locking the locking component to the said internal surface of the said tube, the matrix also fills at least part of the tube thereby 31 improving the compression and deflection resistance of the tube, and thus the 32 building assembly as a whole. In one embodiment, method comprises partially filling 33 the said tube with flowable matrix before setting the matrix. However, in another 34 embodiment, the method comprises substantially filling the tube with flowable matrix before inserting the first locking component into the tube and setting the flowable 36 matrix, therby hardening the flowable matrix to lock the first locking component 1 against the said internal surface of the tube. In the latter embodiment in particular, 2 the compression and deflection resistance of the tube is increased significantly.

4 In some embodiments, the method may further comprise inserting a washer into the said tube of the first building portion before injecting (or introducing) the flowable 6 matrix and before inserting the first locking component into the tube, the washer 7 blocking the flow of flowable matrix.

9 In an alternative embodiment, the method comprises integrally forming a washer with the tube of the first building portion before injecting (or introducing) the matrix and 11 before inserting the first locking component into the said tube.

13 In embodiments where the matrix substantially fills the tube, the washer may be 14 omitted because it is not necessary to block the flow of unset matrix during installation of the interlock.

17 The locking component or the first and/or second locking components may comprise 18 one or more external faces having one or more ridges extending therefrom, and the 19 method may further comprise coating one or more of the one or more ridges in flowable matrix and setting the said flowable matrix thereby hardening the matrix to 21 lock the locking component against the said internal surface of the said tube.

23 The one or more ridges increase the surface area of the external faces of the locking 24 components, thereby increasing the surface area of the locking components to which the set matrix can bond. This increases the strength of the locking action provided by 26 the locking means against the internal surface of the said tube.

28 Typically, the external faces of the locking components comprise one or more 29 serrations between one or more respective pairs of ridges.

31 In embodiments where the locking components comprise tapered self-centring 32 portions, typically the said external faces of the locking components comprise one or 33 more external faces of the tapered self-centring portions.

Typically, the one or more ridges extend from external faces of the locking 36 components at an intermediate portion of the locking components between their 37 proximal ends (connected to the body) and their distal ends.

2 As explained above, only the (first) locking component may be locked to the internal 3 wall of a tube of a first building component, or the first locking component may be 4 locked to the internal wall of a tube of a first building component and the second locking component may also be locked to the internal wall of a tube of a second 6 building component. Accordingly, although some features of the locking means are 7 discussed above with respect to the lock between the (first) locking component and 8 the internal wall of the tube of the first building portion, it will be understood that these 9 features are equally applicable to (where provided) a lock between a second locking component and the internal wall of the tube of a second building portion.

12 The invention also envisages a method of assembling a modular building structure 13 comprising substantially filling respective tubes of a plurality of building portions with 14 a flowable matrix, vertically stacking the said tubes and interconnecting each vertically adjacent pair of tubes by inserting a first locking component of an interlock 16 into a first tube of the said pair, inserting a second locking component into a second 17 tube of the said pair and locking at least one of the locking components of each 18 interlock to an internal surface of the tube into which it extends. Typically, the first 19 locking component of the each interlock is coupled to the second locking component of the interlock by a body. The method may further comprise bridging between the 21 tubes of the said pair with the body.

23 Additionally or alternatively, the method may further comprise closing a top end of the 24 uppermost tube in the stack with a capping interlock, the said interlock comprising a body and a locking component extending from the body into the top end of the said 26 uppermost tube (or if only one tube is provided, a top end of that tube), the body 27 typically engaging the top end of the tube (and typically remaining outside of the 28 tube). The method may further comprise locking the locking component to the said 29 internal surface of the tube, e.g. by an expandable cap or by injecting (or introducing) a flowable matrix into the tube before inserting the locking component into the tube.

31 thereby at least partially immersing the locking component in the flowable matrix.

32 The method may then comprise setting the flowable matrix, thereby hardening the 33 flowable matrix, after the locking component has been inserted into the tube, thereby 34 locking the locking component to the internal surface of the tube. Preferably, the method comprises substantially filling the tube with the matrix.

1 The method may further comprise closing a bottom end of the lowermost tube in the 2 stack (or where only one tube is provided, that tube) with a base interlock comprising 3 a first locking component extending into the lowermost end of the tube and being 4 locked to the internal surface thereof by a locking means, the first locking component extending from a first side of a body, and coupling a second locking component 6 (which may for example comprise a plate) extending from (or even being) a second 7 side of the body opposite the first side and to a foundation of the modular building 8 structure. Preferably the method further comprises injecting (or introducing) a 9 flowable matrix into the tube before inserting the first locking component into the tube, thereby immersing at least part of the first locking component in flowable matrix, and 11 setting the matrix thereby hardening the matrix to lock the first locking component 12 against the internal surface of the said tube. Preferably, the method comprises 13 substantially filling the tube with the matrix.

21 In some embodiments, the method may comprise tuning the material composition of 22 (e.g. by adding one or more additives) a matrix for particular building requirements 23 (e.g. required torsion, compression and deflection resistances), to withstand 24 earthquakes of particular magnitudes and/or to set in a particular time in particular environmental conditions (e.g. temperatures). The method may further comprise 26 tuning the material composition of the matrix (e.g. by adding one or more acoustic 27 dampening additives thereto) to alter (e.g. increase) the sound absorption properties 28 of the structure. The method may further comprise inserting one or more acoustic 29 dampening washers in to the tube(s) to increase the sound absorption properties of the structure.

32 A third aspect of the invention provides an interlock for use in assembly of a modular 33 building structure comprising one or more tubes, the interlock comprising: a locking 34 component extending from (and typically coupled to) a body, the locking component having a self-centring portion comprising a cross section perpendicular to its 36 longitudinal axis, the said cross section tapering down in width between a proximal 37 end of the self-centring portion adjacent to the body and a distal end of the self- 1 centring portion opposite the proximal end, and wherein the locking component has a 2 locating portion comprising a first substantially planar external face and a second 3 substantially planar external face, the second substantially planar external face being 4 substantially orthogonal to the first substantially planar external face such that a cross section through the locating portion perpendicular to the longitudinal axis of the said 6 locking component has an angular perimeter.

8 By providing the locking component with a locating portion having orthogonal external 9 faces, the torsional resistance of a building assembly comprising the interlock can be increased. This is because the orthogonal faces make it more difficult for the 11 interlock to rotate relative to a tube in which it may be inserted in use. In addition, by 12 providing the locking component with a self-centring tapered portion, the locking 13 component is self-centring despite having a cross section perpendicular to its 14 longitudinal axis having orthogonal external faces.

16 Preferably, the said cross section of the locking component tapers down in width in 17 two orthogonal dimensions between its proximal end and its distal end.

19 The interlock may comprise first and second locking components coupled together by the body. The second locking component may extend from the body in a direction 21 parallel to the first locking component. In one embodiment the body comprises a first 22 side and a second side opposite the first side, the first locking component extending 23 from the first side and the second locking component extending from the second side.

24 Typically, the body comprises a plate. In one embodiment, the plate comprises a first face and a second face opposite the first face, the first locking component extending 26 from the first face and the second locking component extending from the second 27 face. The plate may have a cross section perpendicular to the longitudinal axes of 28 the first and/or second locking components having a maximum width equal to the 29 maximum width of a cross section of the first and/or second locking component in a direction perpendicular to its or their longitudinal axes. More typically, the said cross 31 section of the plate has a greater width than the maximum width of the cross sections 32 of the first and second locking components in a direction perpendicular to its or their 33 longitudinal axes. The maximum width of the said cross section of the plate may be 34 substantially equal to an outer diameter (or maximum external width of the axial cross section) of the said tube(s) of the first and/or second building portions.

1 The locking components typically have a common longitudinal axis. The first and 2 second locking components may be different from each other (e.g. they may have 3 different sizes or shapes) in which case they can be used to join together modular 4 building structures having different types of tube, but more typically the first and second locking components are substantially identical (e.g. they have substantially 6 identical sizes and shapes) in which case they can be used to join together modular 7 building structures having tubes with substantially similar properties.

9 Preferably the said angular shape is a quadrilateral shape such as a square or a rectangle.

12 The first locking component may comprise a bore extending through it parallel to its 13 longitudinal axis and the second locking component comprises a bore extending 14 through it parallel to its longitudinal axis.

16 The bores through the first and second locking components may be co-axial and in 17 communication with each other via a bore through the body.

19 The locking component or the first and/or second locking components may comprise external faces having one or more ridges extending therefrom.

22 The one or more ridges increase the surface area of the external faces of the locking 23 components, thereby increasing the surface area of the locking components to which 24 a matrix can bond. When a set matrix is used to lock one of the locking components against the internal surface of one of the said tubes, this increases the strength of the 26 locking action provided by the locking means.

28 Typically, the external faces of the locking component(s) have one or more 29 serrations, e.g. between adjacent pairs of ridges.

31 Typically the said external faces of the locking component(s) comprise one or more 32 external faces of the self-centring portion.

34 Typically, the one or more ridges extend from external faces of the locking components at an intermediate portion of the locking component(s) between its or 36 their respective proximal ends (which are adjacent to the body) and its or their distal 37 ends opposite their respective proximal ends.

2 A fourth aspect of the invention provides kit of parts for assembling a modular 3 building structure comprising one or more tubes, the kit of parts comprising: 4 an interlock having a locking component extending from a body; and at least part of a locking means (such as a locking mechanism) for locking the locking 6 component to an internal surface of the tube of the first building portion.

8 Typically, the locking component has a self-centring portion having a cross section 9 perpendicular to its respective longitudinal axis which tapers down in width (preferably in two orthogonal dimensions) between a proximal end adjacent (and 11 typically coupled) to the said body and a distal end opposite the proximal end.

13 In one embodiment the interlock comprises first and second locking components 14 coupled together by a body.

16 In one embodiment, two locking means may be provided per pair of locking 17 components, one for locking the first locking component to the said internal surface of 18 a tube of a first building portion and one for locking the second locking component to 19 an internal surface of the tube of a second building portion. However, in another embodiment, only one lock may be provided per pair of locking components.

22 In one embodiment the body comprises a first side and a second side opposite the 23 first side, the first locking component extending from the first side and the second 24 locking component extending from the second side. Typically, the body comprises a plate. In one embodiment, the plate comprises a first face and a second face 26 opposite the first face, the first locking component extending from the first face and 27 the second locking component extending from the second face. The plate may have 28 a cross section perpendicular to the longitudinal axes of the first and/or second 29 locking components having a maximum width equal to the maximum width of a cross section of the first and/or second locking component in a direction perpendicular to its 31 or their longitudinal axes. More typically, the said cross section of the plate has a 32 greater width than the maximum width of the cross sections of the first and second 33 locking components in a direction perpendicular to its or their longitudinal axes. The 34 maximum width of the said cross section of the plate may be substantially equal to an outer diameter (or maximum external width of the axial cross section) of the said 36 tube(s) of the first and/or second building portions.

9 Typically, the locking component or the first and/or second locking components comprise locating portions.

12 Preferably where two locking components are provided, the first locking component 13 comprises a bore extending through it parallel to its longitudinal axis and the second 14 locking component comprises a bore extending through it parallel to its longitudinal axis. Typically the bores through the first and second locking components are co- 16 axial and in communication with each other via a bore through the body.

18 In some embodiments, the kit of parts comprises a rod having an outer diameter 19 substantially equal to inner diameters of the bores through the first and second locking components and the body. Typically the inner diameters of the said bores are 21 substantially equal to each other. The rod may be threaded.

23 In some embodiments, the kit of parts further comprises one or more expandable 24 caps sized to be fitted over the distal end of the first and/or second locking components. The caps may be as described above with respect to the first aspect of 26 the invention.

28 The kit of parts may also comprise one or more threaded nuts. The nuts typically 29 have an internal thread which is compatible with the thread provided on the external surface of the rod.

32 The locking component or the first and/or second locking components may comprise 33 external faces having one or more ridges extending therefrom. The one or more 34 ridges increase the surface area of the external faces of the locking components, thereby increasing the surface area of the locking components to which a matrix can 36 bond. When a set matrix is used to lock one of the locking components against the 1 internal surface of one of the said tubes, this increases the strength of the locking 2 action provided by the locking means.

4 In some embodiments, the external faces of the locking components comprise one or more pairs of ridges and one or more serrations between the or each pair of ridges.

7 Typically the said external faces of the locking components comprise one or more 8 external faces of the tapered portions of the said locking components.

Typically, the one or more ridges extend from external faces of the locking 11 components at an intermediate portion of the locking components between their 12 proximal ends (which are typically adjacent the body) and their distal ends (typically 13 opposite the respective proximal ends).

In some embodiments, the at least part of a locking means comprises one or more 16 (typically polymer, such as Fosroc Conbextra GB grout) additives for producing a 17 (typically polymer modified) flowable matrix which hardens when set. Preferably 18 additives capable of being used to produce a polymer modified matrix are provided.

19 The said at least part of a locking means may comprise two or more materials mixable to create a suitable matrix without requiring any additional matrix mixture 21 components.

23 A choice of additives may be provided so that the user of the kit can select one or 24 more of the additives to modify the acoustic dampening and thermal (e.g. setting time, setting temperature) properties of the matrix.

27 A fifth aspect of the invention provides a building comprising a modular building 28 structure according to the first aspect of the invention or an interlock according to the 29 third aspect of the invention.

31 The preferred and optional features discussed above are preferred and optional 32 features of each aspect of the invention to which they are applicable. For the 33 avoidance of doubt, the preferred and optional features of each aspect of the 34 invention are also preferred and optional features of all of the other aspects of the invention, where applicable.

1 Descriition of the Drawings 3 An example embodiment of the present invention will now be illustrated with 4 reference to the following Figures in which: 6 Figure 1 shows an interlock for joining together first and second tubes within a 7 modular building structure; 9 Figure 2 is a perspective view of the top half of the interlock of Figure 1 and an expandable cap for locking one of the locking components of the interlock to an 11 internal surface of a tube within a modular building structure; 13 Figure 3 is a perspective view of the top half of the interlock of Figure 1 with the 14 expandable cap of Figure 2 being installed on the distal end of the top locking component of the interlock; 17 Figure 4 is a sectional view through a modular building structure comprising two 18 tubes connected together at least partly by the interlock of Figure 1 and the 19 expandable cap of Figures 2 and 3; 21 Figure 5 is a sectional view through a modular building structure comprising two 22 tubes connected together by the interlock of Figure 1 and a hardened matrix which 23 substantially fills the tubes; Figure 6 is a sectional view through a modular building structure comprising two 26 tubes connected together by the interlock of Figure 1 and a hardened matrix which 27 partially fills the tubes, a pair of axial washers being provided within the tube to 28 control the axial flow of flowable matrix during assembly of the modular building 29 structure; and 31 Figure 7 shows a base interlock which may couple a building portion to a building 32 foundation.

34 Detailed Descrirtion of an Examrle Embodiment 36 Figure 1 is a perspective view of an interlock 1 comprising a first locking component 2 37 extending from a first side 6 of a body 8 and a second locking component 4 extending 1 from a second side 10 of the body 8 opposite the first side 6. The body 8 in this 2 example comprises a plate, the first side 6 being a first face of the plate and the 3 second side 10 being a second face of the plate opposite the first face. The first and 4 second locking components 2, 4 comprise respective co-axial bores extending along their lengths parallel to their longitudinal axes (the longitudinal axes of the bores 6 being co-axial and being indicated on Figure 1 by a dotted line). A corresponding 7 bore is provided through the plate 8, the bore through the plate also being co-axial 8 (and in communication) with the bores extending through the first and second locking 9 components 2,4. Arod 12 extends through the co-axial bores of the first and second locking components and the plate 8. Nuts 14, 15 may also be provided as part of a 11 locking mechanism for locking one or both of the locking components to a first (and 12 optionally a second) building portion. Typically (but not necessarily) the external 13 surface of the rod 12 is threaded and the nuts 14, 15 have threaded internal surfaces 14 which are compatible with the threads on the external surface of the rod 12. The locking components 2, 4 are typically identical, the only difference being that they 16 extend in opposite directions from opposite sides of the body 8. Accordingly, only the 17 first locking component 2 will be described in detail, it being understood that the 18 second locking component 4 typically has identical features.

The plate 8 has a quadrilateral (e.g. square) cross section perpendicular to the 21 longitudinal axes of the first and second locking components, the said cross section 22 having a width w, and a height h orthogonal to each other. The first locking 23 component 2 comprises a locating portion 17 at a proximal end thereof adjacent and 24 coupled to or integrally formed with the first side 6 of the body 8. The locating portion 17 has a cross section perpendicular to the longitudinal axis of the locking component 26 2 having a width w1 and a height h1 orthogonal to each other. Typically, the width wp 27 of the plate cross section is greater than the width w1 of the first locking component 28 cross section and the height h of the plate cross section is greater than the height h1 29 of the first locking component cross section.

31 The locating portion 17 of the first locking component comprises a first pair of 32 opposite substantially planar faces 19, 20 and a second pair of opposite substantially 33 planar faces 22, 24, the planar faces of each pair being substantially parallel to each 34 other. Typically the locating portion of the locking component 2 is not tapered. The first locking component 2 also has a distal end 18 opposite the locating portion and 36 remote from the body 8 (relative to the proximal end 17).

1 The first locking component 2 also comprises a self-centring portion 30 extending 2 between its proximal and distal ends 17, 18. The self-centring portion 30 has a cross 3 section perpendicular to the longitudinal axes of the first locking component 2 which 4 substantially tapers down in width and height (i.e. in two orthogonal dimensions) with increasing distance from the proximal end 17 towards the distal end 18. The self- 6 centring portion 30 typically comprises a first opposing pair of faces 32, 34 which 7 (generally -i.e. not accounting for discontinuities provided by ridges 50 and serrations 8 52 -see below) converge towards each other from the proximal end 17 towards the 9 distal end 18 and a second pair of opposing faces 36, 38 which also (generally -i.e. not accounting for discontinuities provided by ridges 50 and serrations 52 -see 11 below) converge towards each other from the proximal end 17 towards the distal end 12 18. Chamfered edges 40 may also be provided at the intersections between the 13 faces of the first pair of converging faces 32, 34 and the faces of the second pair of 14 converging faces 36. 38 adjacent the distal end 18. Angled recesses 42 may be provided at the intersections between the faces of the first pair of converging faces 16 32, 34 and the faces of the second pair of converging faces 36, 38 adjacent the 17 proximal end 17, said angled recesses tapering down in size with increasing distance 18 from the proximal end llto the distal end 18.

The external faces 32,34 and 36,38 of the self-centring portion 30 are each provided 21 with a series of ridges 50 with corresponding serrations 52 extending between 22 adjacent pairs of ridges 50. Each ridge 50 is provided with a taper such that the 23 shortest distance between an external surface of the ridge 50 and the longitudinal 24 axis of the first locating portion 2 decreases as the ridge 50 extends towards the distal end 18. The series of ridges 50 provided on the respective pairs of converging 26 faces 32, 34 and 36, 38 are typically (but need not be) substantially identical.

28 Figure 2 shows the top half of the interlock 1 showing only the first locking component 29 2. The rod 12 and the nut 14 are omitted for clarity. The axial bore 60 extending through the first locking component 2 is shown more clearly in Figure 2 than in Figure 31 1. Also shown in Figure 2 is an expandable cap 70 which can be fitted over the distal 32 end 18 of the first locking component 2 in order to lock the first locking component 2 33 to the internal surface of a tube (see below). The cap 70 comprises four wedge 34 portions 72-78 arranged into pairs of opposing wedge portions, each wedge portion comprising a thick end 72a-78a tapering to a respective thin end 72b-78b. The 36 wedge portions 72-78 are coupled together at their thick ends 72a-78a by a central 37 portion 80 comprising an axial bore 82 extending through the cap 70. The axial bore 1 82 is positioned such that, when the cap 70 is fitted over the first locking component 2 2, the axial bore 82 is aligned with the axial bore 60 extending through the locking 3 component 2. The wedge portions 72-78 are tapered such that opposing internal 4 faces 72c-78c of the wedge portions 72-78 diverge away from each other with increasing distance from the central portion 80 towards their thin ends 72b-78b so 6 that they conform to the converging side faces 32, 34, 36 and 38 of the self-centring 7 portion 30 of the first locking component 2. The wedge portions 72-78 of the cap 70 8 are sized to cover at least part of the self-centring portion 30 of the locking 9 component 2. Due to the presence of the ridges 50 on the converging side faces 32, 34, 36 and 38, the internal faces of the wedge portions 72c-78c do not typically 11 contact the serrations 52 on the converging side faces 32, 34, 36 and 38 when the 12 cap 70 is fitted over the distal end of the first locking component 2. This is shown in 13 Figure 3.

As also shown in Figure 3, when the cap 70 is installed on the first locking 16 component, the nut 14 is typically fitted over the cap 70 such that the nut can be 17 tightened to tighten the cap 70 against the first locking component 2. When the nut 18 14 is tightened against the cap 70, the cap 70 more tightly engages the self-centring 19 portion 30 of the locking component 2, causing the wedge portions 72-78 to pivot outwards (i.e. away from a longitudinal axis of the cap) about respective lines of 21 intersection between the thick ends 72a-78a of the wedge portions 72-78 and the 22 central portion 80 of the cap 70. As a result, the width and height of the cap 70 23 expands. As explained below, this effect can be used to lock the locking component 24 2 to an internal surface of a tube.

26 Figure 4 is a sectional view showing respective ends of first and second tubes 90, 92 27 each comprising a longitudinal bore QUa, 92a extending along its length and 28 terminating in apertures at opposing ends of the tube (only apertures 94, 96 in 29 respective first ends of the tubes 90, 92 are shown in Figure 4). The bores 90a, 92a have cross sections perpendicular to their longitudinal axes which are substantially 31 quadrilateral (e.g. square or rectangular) in shape. The first locking component 2 of 32 the interlock 1 extends into the aperture 94 provided in a first end of the first tube 90 33 and the second locking component 4 of the interlock 1 extends into aperture 96 34 provided in a first end of the second tube 92. The self-centring portions 30 of the locking components 2 aid their insertion into the respective ends of the tubes 90, 92 36 by guiding the locking components into the said respective ends of the tubes 90, 92 37 when the alignment of the locking components 2, 4 and the apertures 94, 96 on the 1 respective ends of the tubes is imperfect. Typically, the self-centring portions 30 2 contact the edges of the respective apertures during insertion of the locking 3 components 2, 4 into the respective ends of the tubes and (physically) guide the 4 locking components 2, 4 into the respective apertures 94, 96. The fact that the ridges 50 taper down in size as the ridges 50 extend towards the distal ends 18 of the 6 locking components 2, 4 may also aid the insertion of the locking components 2, 4 7 into the respective apertures 94, 96. Again, if the alignment of the locking 8 components and the respective apertures is imperfect, the ridges 50 can help to 9 physically guide the locking components into the apertures.

11 Typically, the shapes of the cross sections of the bores 90a, 92a (or at least the 12 portions of the bores 90a, 92a occupied by the respective first and second locking 13 components 2, 4) perpendicular to their longitudinal axes conform to the shapes of 14 the cross sections of the locating portions 16 of the locking components 2, 4 perpendicular to the longitudinal axes of the respective locking components 2, 4 (and 16 typically perpendicular to the opposing side walls 19, 20 and 22, 24 of the locating 17 portions of the locking components 2, 4). The locating portions 16 of the locking 18 components 2, 4 typically have widths w1 and heights h1 which are substantially equal 19 to the extent of a cross section of the longitudinal bore through its longitudinal axis in two orthogonal dimensions. By providing the said cross sections of the locking 21 components with shapes which conform to the said cross sections of the said internal 22 bores of the tubes into which they extend, the torsional resistance of the assembly 23 comprising the tubes 90, 92 and the interlock 1 is typically increased. This is 24 because it is typically more difficult for locking components 2, 4 conforming to the shape of the bore to rotate relative to the said tube than locking components 2, 4 26 having said cross sections which do not conform to the said cross sections of the said 27 internal bores. In addition, the angled (i.e. non-rounded, and in this example 28 quadrilateral) perimeters of the said cross sections make it even more difficult for the 29 interlock and the tube to rotate relative to each other.

31 Although not shown in the example of Figure 4, the locating portions are typically 32 received into the apertures of the tubes with an interference fit. That is, the opposing 33 side walls 19, 20 and 22, 24 of the locating portions typically frictionally engage the 34 internal surface of the longitudinal bore of the tubes. Because the locating portions are adjacent the proximal ends of the locating portions, this frictional engagement 36 provides feedback during assembly that the locking components have been 37 accurately and fully inserted into the respective ends of the tubes.

2 The body 8 is not typically inserted into either of the apertures 94, 96 and instead 3 forms a bridge between the tubes 90, 92.

Respective caps 100, 110 (each of which is identical to cap 70 described above) are 6 fitted to the distal ends of the locking components 2,4. A rod 12 extends through the 7 axial bores of the first and second locking components 2, 4, the plate 8 and the caps 8 100, 110, and the nuts 14, 15 are provided with internal threads which are compatible 9 with external threads on the rod 12. The caps 100, 110 are tightened against the distal ends of the locking components by tightening respective nuts 14, 15 (typically 11 by threadably screwing the nuts on the threaded external surface of the rod 12) over 12 the caps 100, 110 towards the locking components 2, 4. As explained above, this 13 causes the cross sectional (i.e. cross section perpendicular to the longitudinal axes of 14 the respective locking components) widths and heights of the caps 100, 110 to increase. The nuts 14, 15 ensure the continued engagement between the caps 100, 16 110 and the locking components 2, 4, while the said expanded external widths and 17 heights of the caps 100, 110 cause the caps to frictionally engage the internal 18 surfaces of the longitudinal bores of the respective tubes 90, 92. This locks the 19 locking components 2, 4 to the internal surfaces of the longitudinal bores 90a, 92a of the respective tubes 90, 92, thus joining the tubes 90, 92 (and thus the first and 21 second building components) together and increasing the resistance of the interlock 1 22 against rotation relative to the tubes 90, 92.

24 In another embodiment, the first locking component 2 may be locked to the said internal surface of the tube 90 of the first building portion, the second locking 26 component 4 not being locked directly to the internal surface of the tube 92. The first 27 locking component 2 of a first interlock may be inserted into the aperture 94 of the 28 tube 90 and locked to an internal surface thereof by a first cap (e.g. using a nut 14) as 29 above. The second locking component 4 of the first interlock may be inserted into the aperture 96 of the tube 92 but not locked to the internal surface thereof (the nut 15 31 may be omitted). A first locking component 2 of a second interlock may be inserted 32 into an aperture on the second end of the tube 92 (typically opposite the aperture 96 33 first end of the tube 92) and locked to an internal surface thereof by a second cap 34 (e.g. using a nut 14). The caps locking the first locking component 2 of the first interlock to the internal surface of the tube 90 and the second locking component 4 of 36 the second interlock to the internal surface of the tube 92 help to prevent relative 37 rotation of the tubes 90, 92 and the first and second interlocks. These said caps also 1 indirectly couple the second locking component 4 of the first interlock to the tube 92.

2 The weight of the building structure above the second building portion helps to retain 3 the said second locking component 4 of the first interlock in the said first end of the 4 tube 92. It will be understood that multiple (including three or more) building components comprising tubes may be stacked on top of each other and 6 interconnected using the interlocks and expandable cap locking mechanisms.

8 An alternative means for locking the locking components 2, 4 to the tubes 90, 92 is 9 illustrated in Figure 5. In this embodiment, the caps 100, 110 and nuts 14, 15 are (typically) omitted. Instead, the tubes 90, 92 are substantially filled with a flowable 11 (workable) matrix (such as dO or C85 grade concrete, typically comprising one or 12 more polymer additives such as Fosroc Conbextra GB grout) before the first and 13 second locking components 2, 4 of the interlock 1 are inserted into the apertures 94, 14 96 in the respective ends of the tubes 90, 92. The locking components 2,4 are then inserted into the respective ends 94, 96 of the tubes 90, 92 such that they are at least 16 partially immersed in the flowable matrix. The flowable matrix typically extends 17 between the immersed portions of the locking components 2, 4 (which typically 18 comprises the self-centring portions 30 and/or the distal ends 18) and the internal 19 surfaces of the longitudinal bores 90a, 92a. Next, the flowable matrix is set (typically thermoset), such that the matrix hardens. Once hardened, the matrix acts as a 21 locking mechanism which locks the locking components to the internal surfaces of the 22 bores 90a, 92a so as to (further) inhibit the relative rotation of the interlock and the 23 tubes 90, 92, thereby improving the torsion resistance of the modular building 24 structure. In addition, by substantially filling the tubes 90, 92 with a hardened matrix, the deflection (bending) and compression resistance of the tubes 90, 92 is also 26 significantly increased. Thus, if the rod 12 (which when in tact acts as a stiffening 27 rod) snaps (e.g. during an earthquake), the building structure can retain its structural 28 integrity due to the presence of the hardened matrix in the tubes. The matrix also 29 improves the fire resistance of the tube as the matrix is capable of absorbing heat (i.e. it will act as a heat sink), and helps to absorb sound waves which reduces the 31 transmission of sound waves around the modular building structure. Where the tubes 32 90, 92 are substantially filled with matrix, both the first and second locking 33 components 2, 4 of the interlock 1 are typically locked to the internal surfaces of the 34 respective bores 90a, 92a of the tubes 90, 92. The ridges 50 extending from the self-centring portions 30 of the locking components 2, 4 provide the components with 36 increased surface areas with which to bond with the matrix. Accordingly, the ridges 37 50 help to increase the strength of the lock provided by the interaction of the 1 hardened matrix, the interlocking components 2, 4 and the internal surfaces of the 2 tubes 90, 92.

4 The material composition of the matrix may be "tuned" (varied) for particular building requirements (e.g. required torsion, compression and deflection resistances) and/or 6 to withstand earthquakes of particular magnitudes. In addition, the material 7 composition of the matrix can be tuned/varied to provide the matrix with particular 8 setting times in given environmental conditions (e.g. temperatures). For example 9 modular building structures in countries having lower average temperatures may require a matrix composition having a lower setting temperature and/or quicker 11 setting times than modular building structures in countries having higher average 12 temperatures.

14 Multiple (including two or more, or three or more) building components may be stacked on top of each other and interconnected using the interlocks and by 16 substantially filling the columns with matrix as discussed above to create one or more 17 integral columns each column having substantially no discontinuities in the load path 18 extending along it. Such integral columns thus provide extremely strong structures 19 with greatly improved torsion, deflection and compression strength over existing modular building structures.

22 In another alternative embodiment illustrated in Figure 6, the matrix only partially fills 23 the tubes 90, 92. In this case, a (typically polystyrene) washer 130 may be inserted 24 into the tube 90 before the first locking component 2 is inserted into the aperture 94.

The washer 130 typically comprises an axial bore which slides over the rod 12 during 26 installation. The washer 130 is typically provided with an interference fit in the bore 27 90a of the tube 90 such that it blocks the flow of flowable matrix. The washer 130 28 may be retained in an axial position with respect to the tube 90 by the nut 14. Next, 29 flowable matrix is injected (or introduced) into the aperture 94 to substantially fill the volume of the bore BOa between the washer 130 and the aperture 94 into which the 31 first locking component 2 is to be inserted. The first locking component 2 is then 32 inserted into the aperture while the matrix is still flowable, at least partially immersing 33 the first locking component 2 in the flowable matrix. Next, the matrix is set, and 34 thereby hardened. The hardened matrix extends between the first locking component 2 and the internal surface of the bore BOa of the tube 90 so as to lock the 36 first locking component 2 to the internal surface of the bore 90a. By locking the first 37 locking component 2 to the internal surface of the bore 90a, relative rotation of the 1 first locking component 2 and the tube 90 is inhibited, thereby increasing the torsion 2 resistance of the modular building structure. The filled portion of the tube between 3 the washer and the aperture also has improved resistance to compression and 4 deflection forces. The matrix also improves the fire resistance of the tube as the matrix is capable of absorbing heat. The matrix also helps to absorb sounds, thus 6 reducing the transmission of sound waves around the building structure.

8 As above with respect to the embodiments comprising the expandable cap, both the 9 first and second locking components 2, 4 of the interlock 1 may be locked (e.g. with hardened matrix) to the respective internal surfaces of the bores 90a, 92a into which 11 they extend (in which case one washer may be provided per locking component).

12 However, in some embodiments the first locking component 2 may be locked to the 13 said internal surface of the tube 90 of the first building portion, the second locking 14 component 4 not being locked directly to the internal surface of the tube 92. In this case, a first washer 130 may be inserted into the aperture 94 of the first tube 90 as 16 above, and a second washer 142 may be inserted into an aperture 140 provided in a 17 second end of the second tube 92 opposite the first end comprising the aperture 96.

18 Flowable matrix may then be injected (or introduced) into the volume between the 19 washer 130 and the aperture 94 of the first end of the tube 90 into which the first locking component 2 is to be inserted. Next, the first locking component 2 is inserted 21 into the aperture 94 where it is at least partially immersed in flowable matrix. The 22 matrix is then set, thereby hardening to lock the first locking component 2 to the 23 internal surface of the bore 90a of the tube 90 as above. Meanwhile, the second 24 locking component 4 is inserted into the aperture 96 of the first end of the tube 92.

However, the second locking component 4 need not be locked to the internal surface 26 of the bore 92 (either by matrix or any other locking means). The nut 15 is therefore 27 typically omitted. The volume between the second washer 142 and the aperture 140 28 at the second end of the tube 92 is substantially filled with flowable matrix. The first 29 locking component 2 of a second interlock 150 may then be inserted into the said volume such that the first locking component 2 of the second interlock 150 is at least 31 partially immersed in the flowable matrix. The flowable matrix is then set, thereby 32 hardening to lock the first locking component 2 of the second interlock to the internal 33 surface of the bore 92a of the tube 92. A third building component comprising a third 34 tube 145 may then be stacked on top of the tube 92, the second locating portion 4 of the second interlock being inserted into an aperture of the third tube 140 to extend 36 the building further in a vertical direction. The set matrix locking the first locking 37 component 2 of the first interlock to the internal surface of the tube 90 and the first 1 locking component 2 of the second interlock to the internal surface of the tube 92 2 helps to prevent relative rotation of the tubes 90, 92 and the first and second 3 interlocks and indirectly couples the second locking component 4 of the first interlock 4 to the tube 92 of the second building component.

6 In each of the above embodiments, the rod acts as an assembly aid for inserting the 7 first and second locking components into the said tubes by helping to align the 8 locking components with the apertures in the ends of the tubes. The rod also 9 increases the stiffness and the strength of the building assembly.

11 In a modular building structure, different combinations of tubes being partially filled 12 with matrix, tubes being fully filled with matrix and tubes comprising no matrix 13 (instead comprising the expandable cap locking mechanisms) may be used 14 depending on requirements. In addition, different matrix mixtures may be used in different tubes, again depending on requirements.

17 The interlocks and locking means (e.g. expandable caps and matrix) described above 18 are also backwards compatible with existing modular building structures comprising 19 building components having tubes.

21 The ridges 50 and serrations 52 on the external surfaces of the locking components 22 may be omitted, particularly in embodiments which use the expandable cap 70 23 locking means rather than the hardened matrix locking means. In this case, the 24 external faces of the locking components 2,4 may be substantially planar.

26 In some embodiments a plurality of locking components may extend from the first 27 side 6 of the body 8 and/or a plurality of locking components may extend from the 28 second side 10 of the body 8. In this case, a plurality of parallel tubes can be joined 29 together.

31 The body may also comprise a corner section such that the first locking component 2 32 extends at right angles to the second locking component 4 from the body. In this 33 case, the first and second tubes also typically extend at right angles to each other.

It will also be understood that the interlock and locking means need not be used to 36 vertically connect building components together. Alternatively, the interlock and 37 locking means may be used to horizontally connect building components together.

2 The interlock may be provided on its own; together with one or more expandable 3 caps 70; together with one or more polymer additives to add to a commonly available 4 matrix mixture; together with the materials necessary to create a suitable matrix mixture; together with a rod; together with one or more nuts; or any combination 6 thereof.

8 In some embodiments, a capping interlock may be provided to close an end of a tube 9 of a building portion, without connecting the said end of the tube to another building portion. The capping interlock may be identical to the top half of the interlock 1 11 shown in Figure 2, the capping interlock comprising a body and a locking component 12 extending from the body. The locking component may have some or all of the 13 features of the first locking component 2 of the first interlock 1 as described above, 14 and the tube may have some or all of the features of the tubes 90, 92 described above. Typically the locking component extends into the said end of the tube of the 16 building portion and the body portion engages an outer surface of the said end of the 17 tube. The locking component may be locked to an internal surface of the tube by an 18 expandable cap 70 or hardened matrix extending between the locking component 19 and the internal surface of the tube. By locking the locking component to the internal surface of the tube, the torsion resistance of the building structure is increased.

22 Additionally or alternatively, as shown in Figure 7, a base interlock 170 may be 23 provided at an end of a tube of a building portion, typically at an end of a said tube 24 adjacent the building foundations. The base interlock comprises a first locking component 2 extending from a first side of a body 8, the first locking component being 26 substantially identical to the first locking component 2 described above and the body 27 8 being substantially identical to the body described above. The base interlock 170 28 further comprises a second locking component comprising a rubber layer 184 29 extending between first and second substantially planar supporting (e.g. steel) layers 182, 186 forming a sandwich structure. The first supporting layer 182 is attached to 31 or integrally formed with a second side of the body opposite the first side.

33 As above, the first locking component is typically inserted into a tube 175 and locked 34 to an internal surface thereof by, for example, an expandable cap 70 and/or a hardened matrix. The second locking component may be connected (e.g. bolted) to 36 one or more building foundations to secure the tube thereto. As above, by locking the 1 locking component 2 to the internal surface of the tube 175, the torsion resistance of 2 the building structure is significantly improved over existing structures.

4 The rubber sandwich construction of the second locking component may act as a seismic dampener providing a discontinuity in the resonance frequency of a path 6 through the tubes and the interlock.

8 The rubber sandwich construction of the second locking component may also be 9 used in the body 8 of the interlock 1 described above, for example to provide additional acoustic dampening throughout the modular building structure.

12 Further modifications and variations may be made within the scope of the invention 13 herein disclosed.