The present invention relates to a building construction utilising cross-laminated timber (CLT), and in particular, but not exclusively, to a multi-storey CLT building construction.

Background to the Invention

A worldwide interest in timber multi-storey buildings is expected due to the environmental advantages of timber construction when compared to buildings in concrete and steel. Some research suggests that compared to a reinforced concrete multi-storey building, the production of an equivalent timber building emits 65% less carbon dioxide and uses 65% less energy.

One construction proposed for low-rise multi-storey timber buildings utilises cross-laminated timber (CLT) panels as structural elements.

Cross laminated timber is created by gluing layers of timber together to form large panels. The layers are orientated so that the grain of timber within each layer is substantially parallel, and the grain in each layer is typically perpendicular to the grain of the immediately adjacent layers. This "cross-laminating" provides reliable strength and stability. The panels of the prior art have been up to 16m long, 3.3m wide and 500mm thick. Pinus radiata, the major plantation timber in New Zealand, is suitable for the manufacturing of CLT panels.

At present, CLT panels have been used in multi-level buildings of around 10 stories or less. For each storey, single storey wall panels are placed. These are overlaid by the floor or roof panels. The panels are connected together by screw fastening methods.

One disadvantage of presently used CLT construction methods is that the wall panels are relatively closely spaced, and are load bearing, and so cannot be conveniently relocated or modified after the building has been constructed. This is particularly inconvenient for commercial buildings which require flexible, reconfigurable letting spaces.

The term "multi-storey" is used herein to refer to buildings having at least two stories. 2015/050037

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The reference to any prior art in the specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in any country. Object of the Invention

It is an object of the invention to provide a shear core for a building and/or a building comprising the shear core and/or a method of manufacturing a shear core for a building, which will overcome or ameliorate problems with such shear cores, buildings and/or methods at present, or at least one which will provide a useful choice.

Other objects of the present invention may become apparent from the following description, which is given b way of example only. Brief Summary of the Invention

According to one aspect of the present invention there is provided a shear core for a building comprising a plurality of laminated timber panels, each panel having at least one side edge shaped to mesh with a side edge of an adjacent panel, to thereby resist relative vertical movement between the panels.

Preferably the laminated timber panels are cross-laminated timber panels.

Preferably the side edges are corrugated.

Preferably at least one of the timber panels comprises at least one side edge comprising substantially triangular corrugations.

Preferably at least one of the timber panels comprises at least one castellated side edge.

Preferably the shear core comprises a filler material between the side edges of at least selected adjacent panels.

Preferably the filler material is a low or non-shrink grout. Preferably the filler material has a compression strength at least equal to that of the timber panels.

Preferably a plurality of the panels are arranged side by side.

Preferably a plurality of the panels are arranged end to end.

Preferably a stabilising means is provided at or adjacent an intersection between vertically adjacent panels.

Preferably the stabilising means encircles the core.

Preferably the stabilising means comprises at least two pairs of interconnected elongate members.

Preferably the elongate members are orientated substantially horizontally.

Preferably a plurality of the panels are arranged such that a lower edge of one of said panels is at a different height to a lower edge of an immediately adjacent panel and/or an upper edge of each said panel is at a different height to an upper edge of an immediately adjacent panel.

Preferably the panels are arranged such that the lower edges of alternate panels are at substantially the same height. According to a second aspect of the present invention there is provided a shear core for a building comprising a plurality of laminated timber panels, each panel having at least one side edge connected to a side edge of an adjacent panel, the connection between the panels being adapted to resist relative vertical movement between the panels, the shear core further comprising at least one stabilising means associated with a plurality of the panels for preventing movement of the panels out of alignment.

Preferably at least one of the stabilising means is provided at or adjacent an intersection between vertically adjacent panels. Preferably at least one of the stabilising means encircles the core. Preferably at least one of the stabilising means comprises at least four, interconnected elongate members. Preferably the elongate members are orientated substantially horizontally.

According to a third aspect of the present invention there is provided a building comprising the shear core of first aspect and/or the second aspect. Preferably the building comprises a plurality of column members.

Preferably the building comprises a plurality of beam members.

Preferably a plurality of the beam members are supported by the core and a respective column member.

Preferably each beam member supported by the core has a connection to the core which allows relative rotation between the beam member and the core about a first axis. Preferably the connection between each beam member and the respective column substantially prevents rotation of the beam member relative to the column in a first rotational direction.

Preferably a plurality of the beam members are supported by respective column members at either end of each beam member.

Preferably the building comprises a foundation and a plurality of core locating members extending from the foundation.

Preferably the core locating members abut the core, but substantially do not resist vertical movement between the core and the foundation.

Preferably the building comprises a plurality of core restraining members engaged with the core and with the foundation. Preferably each said core restraining member comprises a replaceable tension member. According to a fourth aspect of the present invention there is provided a method of

manufacturing a shear core for a building, the method comprising the steps of:

i. providing a first timber panel having at least one side edge;

ii. providing a second timber panel having at least one side edge adjacent the first timber panel, such that a side edge of the first panel is adjacent, but spaced apart from, a side edge of the second timber panel;

iii. enclosing a space between the side edges with boxing material; and iv. filling the enclosed space with a settable filler material.

Preferably each said timber panel is a cross-laminated timber panel.

Preferably the grout material comprises a low or non-shrink grout. Preferably the grout has a compression strength at least equal to that of the timber panels.

According to a further aspect of the present invention there is provided a building comprising a shear core manufactured by the method of the fourth aspect. The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

According to a still further aspect of the present invention, a shear core for a building and/or a building comprising a shear core and/or a method of manufacture of a shear core is substantially as herein described with reference to the accompanying drawings.

Further aspects of the invention, which should be considered in all its novel aspects, will become apparent from the following description given by way of example of possible embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a diagrammatic isometric view of the internal structure of a building of the present invention, with external walls not shown and the floors shown in outline.

Figure 2 is a diagrammatic plan view of the internal structure of the building of Figure 1 , with floors, external walls and ceilings not shown.

Figure 2a is a diagrammatic plan view of the internal structure of a building according to another embodiment of the invention, with floors, external walls and ceilings not shown.

Figure 3 is a very diagrammatic side elevation of a core of a building of the present invention, with stabilisation means not shown for clarity.

Figure 3a is a very diagrammatic side elevation of a core of a building of the present invention, with tension joints shown between vertically adjacent panels.

Figure 4 is an enlarged view of a horizontal cross-section through the joint between two adjacent panels of the core according to one embodiment of the invention.

Figure 5 is a diagrammatic side view of one possible embodiment of a connection

between a beam and a column. Figure 5a is a diagrammatic side view of another possible connection between a beam and a column and between the beam and the core.

Figure 6 is a partial side view of the foundation and the base of the shear core. Figure 6a is a partial view of a horizontal cross section of the core shown in Figure 6.

Figure 6 b is a partial view of a vertical cross section of the core shown in Figure 6. Figure 7 is a partial side view the foundation and the base of the shear core showing the alternative connection means between the hold-down bars and the core.

Figure 7a is a partial vertical cross section of the core with the connection shown in Figure

7.

Figure 8 is a very diagrammatic side elevation of another embodiment of a shear core of the present invention. BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Referring first to Figures 1 and 2, a building made in accordance with the present invention is generally referenced by arrow 100. The building 100 comprises a foundation 1 , a shear core 2, a plurality of columns 3, and a plurality of beam members 4 extending between the core 2 and the columns 3. Floor and ceiling members (not shown) are attached to the beam members.

As can be seen in Figures 2 and 2a, beam members 4 may be provided between adjacent columns 3 as well as between the core 2 and a column 3. The columns and beams are preferably constructed from engineered wood such as glued laminated timber. The columns 3 are preferably provided around an outer perimeter of the building 100. The particular arrangement of beams and columns will vary depending on the building requirements.

Referring next to Figures 2a and 3, the core 2 comprises a plurality of laminated timber panels 5 arranged side by side, and, if necessary, one above the other, to form a hollow column which extends substantially the entire height of the building 00. The core 2 is preferably substantially rectangular or square in cross-section.

The panels 5 are preferably cross-laminated. In one embodiment each panel is substantially 16m long and nominally 3m wide, with laminates of between 20mm to 40mm thick, although longer panels 5 may be used for large, multi-storey applications, if available. In one example panels of less than 6m length (for example around 12 m) may be preferred in order to allow the panels to be shipped inside a standard shipping container. NZ2015/050037

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The number of layers in each panel will depend on the strength and stiffness requirements of the particular building.

The panels 5 have side edges 6 which have a profile shaped to mesh with the side edge 6 of an adjacent panel.

In the embodiment shown the side edges 6a of those panels 5 which form the comers of the core 2 have a substantially castellated profile. The side edges 6b of panels which do not form the corners of the core may have any profile which allows meshing or interlocking with an adjacent panel in such a way as to resist relative vertical movement between the meshed or interlocked panels.

In preferred embodiments of the invention the side edges are corrugated, as shown in Figures 3 and 3a. Suitable profiles including a castellated shape, or more preferably a triangular sawtooth or zigzag profile as shown in Figure 3a.

In a preferred embodiment a suitable filler or grout 11 (see Figure 4) is provided between the side edges 6b of adjacent panels 5. The grout is preferably a low or non-shrink cementitious grout, having a compressive strength which is at least equal to that of the panels. One suitable grout is Sika™Grout 215. Providing grout between the panels 5 allows the width of the panels 5 to be slightly reduced, and makes assembly of the core 2 easier. In an alternative embodiment no grout is provided between the side edges 6b. Here, the panels 5 may abut each other and may be held in place by suitable clamping means until stabilisation means 2 are installed, as is described further below.

Referring next to Figure 4, in one embodiment the front and rear faces 7, 8 of the panels 5 are provided with a rebate 9 adjacent each side edge 6b, Once the panels 5 have been moved into position, a suitably shaped boxing material or "shuttering" 10 is provided to engage the rebate 9 on the similar faces of the adjacent panels 5. With the boxing 10 installed the grout 11 can be pumped into the void defined by the boxing 10 and the side edges 6b. In a preferred embodiment the boxing 10 remains as part of the core 2 after the grout 11 has set.

In one embodiment the castellated joints 6a may have a clearance gap between each adjacent castellation. The gap is preferably sized to allow filling with a suitable drypack grout, for example Sika Grout 212. In one example the size of the clearance gap is around 10mm. 50037

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Referring back to Figures 2a and 3, in one embodiment of the invention the panels 5 of the core are arranged end-to-end, with the upper edge 6c of each lower panel 5 abutting the lower edge 6d of the panel 5 above. As can be seen in Figure 3, the panels 5 are preferably arranged in a horizontally aligned but vertically staggered pattern such that (other than at the base of the building) the lower edge 6d of each panel 5 is at a different height to the lower edge 6d of each immediately adjacent panel 5. In this way, vertically orientated shear forces in the core.2 can transfer tension forces across the boundary between abutting upper and lower panels 5 through the adjacent panel(s), rather than transmitting the force through the connection between the upper and lower panels. In this way tension forces that occur in the core are transferred down to the foundation. In some embodiments the panels 5 on any particular face of the core are arranged to minimum the number of intersections between adjacent upper and lower panels which are in the same horizontal plane and/or to maximise the horizontal spacing between any such intersections which are in the same horizontal plane.

As shown in Figure 3a, in some embodiments tension plates 18 may be provided between the upper edge 6c of a panel and the lower edge 6d of the panel above. The tension plates 18 are preferably secured to the panels by timber rivets, although other suitable fasteners may be used. Referring next to Figure 2a, in a preferred embodiment the butt joint between each pair of vertically adjacent panels 5 is stabilised by suitable stabilisation means 12, for example a plurality of interconnected elongate members which together encircle the core 2. The elongate members may comprise timber or laminated timber beams 3. In another embodiment the stabilisation means 12 may comprise or one or more reinforced concrete members. In some embodiments stabilisation means 12 may be attached to the core 2 at positions corresponding to each of the floors of the building. The stabilisation means 12 assist in preventing the panels 5 from moving out of alignment with each other.

In one embodiment the beams 13 on opposing sides of the core 2 may be connected by suitable tension elements such as threaded steel rods (not shown), which clamp the beams 13 against the outer surface of the core 2. The stabilising means 12 are connected to or otherwise engaged with the upper and lower edges 6c, 6d of the panels 5. In this way the upper and lower edges 6c, 6d of each pair of vertically adjacent panels 5 are prevented from falling out of vertical alignment, and from pulling apart. In some embodiments the stabilising means 12 allow the core to behave as a Howe type truss. The beams 13, in association with the tension elements, are the tension members of the truss. In truss action, the tension in the tension elements produces pressure on the panels of the core that are at right angles to the tension element. The beams at right angles to the tension elements distribute the pressure on the panels of the core and alleviate wood crushing perpendicular to the wood grain.

Referring next to Figure 5, in one embodiment the beams 4 are connected to the columns 3 by means of corbels 14. An inner corbel 14a is provided below the beam 4 and supports the weight of the beam 4. If additional stiffness and strength are required then an outer corbel 14b may be provided above the beam 4, to assist in preventing relative rotation between the column 3 and the beam 4. The fixity between the beams 4 and the columns 3 produces frame action. The main reason for frame action is to reduce horizontal drifts of the building due to lateral loads. However, it also reduces stresses in the core. The connection between the beams 4 and the core 2 is preferably a pin joint which does not resist rotation about a selected substantially horizontal axis.

In the embodiment shown in Figure 5, the outer corbel 4b is shown as a reinforced concrete corbel, but in other embodiments both corbels 14a, 14b may be timber.

Referring next to Figure 5a, in some embodiments only an inner corbel 14a is used. As can be seen in Figure 5a, in some embodiments the connection between the beam 4 and the core 2 is relatively loose, so that the connection between the beam 4 and the core 2 does not resist rotation of the beam relative to the core 2. This may be particularly preferred when the invention is used in seismically active regions.

Referring next to Figures 6 to 6b, a plurality of core locating members 15 extend from the foundation 1 adjacent the core 2. The core locating members 5 are preferably steel

Rectangular Hollow Section (RHS) or I beams or which are embedded in the foundation 1 , with an outer surface in contact with an outer surface of the core 2. At least one core locating member 15 is provided for each side of the core 2. More preferably at least two core locating members 15 are provided for each side of the core 2, one at either end of each side. The core locating members 15 are intended to prevent lateral movement of the core 2 relative to the foundation 1. In seismically prone regions the core locating members may be engaged with the core 2 in such a way as to provide limited or substantially no resistance to relative vertical movement between the core locating member 15 and the core 2, as some rocking of the core relative to the foundation may be desirable as an energy absorbing mechanism in a seismic event, In some embodiments the surface of the core locating member 15 which abuts the core 2 may be coated with low friction coating such as PTFE in order to ensure that the resistance to relative vertical movement is minimised. Additionally or alternatively a small clearance gap may be provided between the core 2 and the core locating member 15.

A plurality of core restraining members 16 are preferably provided between the core 2 and the foundation 1. The core restraining members 16 may comprise replaceable vertical hold-down bars 7 which are designed to deform plastically if the tension force on the hold-down bar caused by the rocking of the core 2 is greater than a predetermined threshold. In this way the hold-down bars 17 act to remove kinetic energy from the building during an earthquake.

In the embodiment shown in Figure 6 the hold-down bars 17 are connected to the core 2 by inclined screws 19. However, in an alternative embodiment (shown in Figures 7 and 7a), the hold-down bars may be connected to the core 2 by means of timber rivets 20.

Those skilled in the art will appreciate that the shear core 2 may function as an elevator shaft and/or stairwell.

Referring next to Figure 8, in an alternative embodiment one or more of the stabilising means 12 described above may be used with an embodiment of the core 2 in which some or all of the side edges of the panels 5 do not interlock or mesh. In this embodiment the method of resisting relative vertical movement between the panels 5 may comprise traditional screw fasteners and/or alternative fastening methods such as straps and/or staples connecting the adjacent panels, and/or the tension plates 18 described above with reference to Figure 3a.

Those skilled in the art will appreciate that preferred embodiments of the present invention provide an arrangement for a shear core made from cross laminated timber which provides improved strength and stiffness compared to present arrangements, particularly for supporting horizontal loads on the building, and also allows for a more open, flexible floor layout. In a particularly preferred embodiment, the system relies on large cross-laminated timber panels being integrated together to form a very large vertical cantilever element (with square hollow or rectangular hollow cross-section), that extends effectively the full height of the building, which is the main element for supporting lateral building loads. In some embodiments the timber panels have a length which is substantially equal to the height of the building.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

Where in the foregoing description, reference has been made to specific components or integers of the invention having known equivalents, then such equivalents are herein incorporated as if individually set forth.

Although this invention has been described by way of example and with reference to possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from the spirit or scope of the appended claims