Te Whare Nui o Tuteata showcases timber technology in construction by utilising different engineered timber products to form the building’s floors, stairs, lift shaft, partitions and primary structural bracing. The approach of displaying mass timber in many forms was part of the architectural concept, with the building’s hallmark timber diagrid used to form the structural bracing, believed to be a world first of its size.

The 8-metre-tall timber diagrid frames and entry canopies use GLT and laminated veneer lumber (LVL). The diagrid comprises of 88 diamond and triangleshaped frames that use innovative dovetail node joints to slot and glue together in a celebration of engineered timber craft. The connections between the diagrid sections consist of flexible U-shaped steel plates (UFP plates) that act as energy-dissipation devices between the timber. The connections also include a component designed to deform during severe earthquakes in order to protect the building.

Designed by Jackson Clement Burrows and built by ICON, the T3 Collingwood office tower delivers 18,200m² of net lettable area over 15 storeys with floor plates ranging from 900 to 1,500 square metres.

The building utilises a hybrid structure combining steel and concrete with XLAM CLT to maximise the benefits from each material. A 2-level, concrete basement was poured, levels ground to 6 were then built using steel and poured concrete. Mass-timber-construction and XLAM CLT was used for floors 6 to 14 and then the roof was poured in concrete.

JCB highlights that Wellington St aims to achieve best-practice sustainable design, encompassing mass timber construction, building performance, occupancy comfort and the urban environment. Timber, including 2360m³ of XLAM CLT, has been used in the structure of the building and the interior fit-out. Inside, visible wood reflects the timber structure of the building, to provide the benefits of a biophilic environment including stress reduction and productivity increases associated with the use of natural materials.

Maria Hindy from ICON has confirmed that utilising XLAM CLT delivered several important benefits that ensured safe, efficient, and sustainable construction.

Despite its size, several covid-19 lockdowns and the Adelaide Oval remaining operational and open to the public throughout construction, the Oval Hotel had a strict 12-month deadline which presented challenges to XLAM, and the project stakeholders involved.

To overcome time constraints, a DfMA process was implemented to increase efficiency, while minimising the construction schedule and costs. XLAM were engaged to provide construction sequencing, shop drawings, as well as manufacturing the XLAM CLT panels.

While the on-site initial construction activity was constrained by the AFL season, XLAM were able to immediately commence prefabrication to ensure the project remained to schedule. The XLAM CLT panels were prefabricated with CNC machines to guarantee all components could be assembled with a high degree of accuracy once on-site.

To verify the XLAM CLT panels for the walls and floors were placed correctly reference marks were set to guide the panel placement and installation process. Once in place the XLAM CLT panels were installed similar to concrete precast panels.

The hotel structure leveraged the existing foundations of precast concrete columns, which support a raised steel transfer. The pre-existing stadium structure also allowed for the lateral stability to install 5-stories of XLAM CLT walls and floors, in turn creating a complex yet efficient form of construction.

The building incorporates many innovative elements typical of a mass timber structure. The reclaimed land required a lightweight construction solution, engineered timber being an obvious choice. The building is supported by 15m long piles penetrating the old seabed to support a concrete ground floor, all main components are wood including 68m³ of XLAM CLT and XLAM AirStairs.

The structural design hinges on the use of lightweight prefabricated engineered timber components. The two storey offices and administration building incorporate a blend of products from XLAM, Nelson Pine Industries and Potius Building Systems.

The main structural support and shear walls comprise XLAM 5-layer 130mm thick CLT panels rising full height of the building. The XLAM CLT panels are connected to the floor slab by cast-in projecting steel dowels over which the factory-drilled panels were lowered, with epoxy adhesive inserted once the panels were positioned. The walls were rapidly installed and wrapped against weather until the building was enclosed. The XLAM CLT walls support a Potius floor fabricated from LVL, while bracing to the open south wall is provided by LVL cross columns.

Floor levels are linked by XLAM AirStairs which provide a strong design feature to the double height entry. Much of the mass timber was sanded and clear finished post installation and left exposed to deliver warmth and ambience to the interior and for biophillic benefits.