Harnessing the strength of triangles
A widespread belief that wooden buildings need to mirror steel and concrete designs has been countered by the Scion Innovation Hub in New Zealand. The world’s largest diagrid structure made of laminated veneer lumber reduces timber requirements by 75% and even withstands earthquakes.
The three peaks welcoming visitors as they arrive at this research building are visible from miles around. Representing the three local Māori tribes, they form the entrance to one of the most innovative wooden buildings of our time. The institute takes its name from the famous Māori ancestor Tuteata, and is called Te Whare Nui o Tuteata, or “the big house of Tuteata”. Situated in Rotorua on the northern island of New Zealand, the Scion Innovation Hub has a resource-friendly structural framework made of timber. It refers to the surrounding forests and uses the concept of branches for its statics.
A branch very rarely sits perpendicular to the trunk. It usually runs diagonally, which lowers the load, and it is this relationship between horizontal and vertical loads that is the key to strength.
Richard Naish, architect
“A branch very rarely sits perpendicular to the trunk. It usually runs diagonally, which lowers the load, and it is this relationship between horizontal and vertical loads that is the key to strength,” explains Richard Naish, architect and founder of RTA Studio. The company has three offices in New Zealand and joined forces with Irving Smith Architects to produce the building design.
Timber construction as tourist attraction
As an entirely transparent building, it is an impressive showcase for the broad spectrum of potential uses for new timber materials. The design acts as an eye-catching case study for the Scion Timber Research Institute housed here, and also as an added attraction for the city. Since opening in 2021, it has actually developed into a popular destination. Hikers come here for lunch in the café after a walk in the neighbouring Whakarewarewa forest. And representatives from industry and local authorities gain inspiration and benefit from practical construction expertise.
This remarkable construction is immediately visible upon entering the building. Its striking three-level diagrid design draws the eye upwards to the ceiling in the lofty heights of the lobby. What’s more, people visiting the centre need little explanation to understand the structural framework.
The diagrids transfer the loads to the fuses which yield in an earthquake and can be replaced.
Richard Naish, architect
In other words, the visible construction is quasi self-explanatory throughout the entire building. Clarification by the project’s timber construction engineers is only required for the U-shaped steel plates between the individual timber construction parts.
In the project film, architect Naish solves the mystery: “The diagrids transfer the loads to the fuses which yield in an earthquake and can be replaced.”
Largest diagrid structure in the world
The structural framework consists of 4,248 components that were prefabricated as 88 triangular frames at the engineering works. Instead of metal connectors, the architects chose wooden dovetail node joints to comply with their brief of creating a timber building with the greatest possible degree of innovation. The construction uses high-performance laminated veneer lumber (LVL), and the upper levels are floored with cross laminated timber.
According to RTA Studio, the Scion Innovation Hub is the first building of this size in the world to use a timber-diagrid structural system. This kind of diagonal grid construction has already proven its worth in steel designs. For instance, Norman Foster’s parabolic skyscraper in London, known as “The Gherkin”, is a prominent example of this approach. Timber construction is also expected to reach new heights with the help of diagrid structural frameworks, as shown in the concept study for River Beech Tower by Perkins+Will. According to their results, a height of 280 metres will be achievable for wooden high-rises with this kind of design.
Zero-carbon construction
One major advantage of this diagrid design is the slender structural framework that reduces the quantity of materials needed. In the case of the Scion Innovation Hub, an even greater amount of material could be saved through use of laminated veneer lumbar, which can bear especially high loads. In the project’s video presentation, Naish explains: “We invented an all-timber node that reduces the timber sizes by 75%.”
We invented an all-timber node that reduces the timber sizes by 75%.
Richard Naish, architect
Additionally, around 500 tonnes of CO2 are stored in the wood used for building. An Etool assessment revealed that this construction method in conjunction with the other materials would achieve zero carbon at the time of completion.
Energy-efficient building operation is enabled by the rear-ventilated double skin facade and patterned glazing that filters the daylight, for example. Inspiration for this pattern, and also for the carved ornamentation at the entrance, was taken from the local Māori tribes.
Indigenous construction methods are circular
The approach to integrating the native inhabitants of New Zealand is more than just lip service here. Above and beyond the formal building design, this government-funded institute has formed a close partnership with these tribes in its research into timber construction. Even today, the traditional Māori assembly halls, called Wharenui, are made of carved timber elements.
In this way, the Māori knowledge of circular construction with natural materials can be passed on by these indigenous peoples and integrated into current research. Collaboration will therefore point the way towards a climate-neutral future.
Text: Gertraud Gerst
Translation: Rosemary Bridger-Lippe
Photos: Patrick Reynolds