Over the past decade, there has been an increasing trend towards using mass engineered timber (MET) as a viable and sustainable complement to traditional materials such as concrete and steel.
The Monterey Kangaroo Point apartments building in Brisbane is Australia’s tallest engineered timber residential tower. The nine-story building features cross-laminated timber (CLT), which is solid-sawn timber bonded together in transverse and longitudinal layers with structural adhesives to produce thick panels. Panels provide similar strength and stiffness to concrete and steel, while also improving fire performance.
As structural engineer, Aurecon designed Monterey Apartments with simplified, light weight construction in mind. Cross-laminated timber is a renewable resource that sequesters carbon, enhances thermal properties and has low embodied energy.
The Monterey building is distinctive in that all floors and walls are framed in CLT panels. The structure is laterally restrained by a concrete core and sits above the city’s Clem 7 Tunnel; timber being the only material light enough, yet with enough strength, to achieve the building’s height and tunnel loading restrictions.
Timber design and construction for tall buildings is relatively new in the Southern Hemisphere but gaining attention very quickly because it results in unique, environmentally sustainable buildings.
Aurecon’s experience designing timber buildings, such as 25 King in Brisbane and Nanyang Technological University Academic Building South, in Singapore, has given us the opportunity to provide valuable input into the new breed of timber buildings emerging in the region.
The timber used on the Monterey project is from a 100 percent renewable resource, has low embodied energy and minimal operational energy due to its thermal properties. It has a lower carbon footprint than traditional building materials and was sourced from certified sustainably managed forests.
When a tree dies or catches on fire, it releases carbon dioxide into the atmosphere, however, when it is used to construct a building, it stores carbon – one cubic metre of timber will store one tonne of carbon. As it’s prefabricated, CLT produces less waste and results in a safer, quieter, less polluted construction site and a faster build, meaning less disruption to the surrounding community.
Monterey Kangaroo Point replaces 1170 m3 of traditional concrete and blockwork with Australian timber. It will be 3 744 tonnes of CO2 better off, which is the equivalent of removing more than 700 cars off the road, for one year, or powering a home for over 300 years.
CLT has useful thermal capabilities and provides thermal mass – it provides 15 times more insulation than masonry and 400 times more than steel.. As solid timber wall panels create the ability to create air-tight compartments, they provide heating and cooling energy reductions as well.
Despite being five times lighter than reinforced concrete, the glue laminated timber used as column elements in this building have similar compressive capacity to 32MPa concrete columns.
Due to the mass and density of CLT, it does not ignite easily, instead burning in a slow, predictable and measurable way. It means that the timber performs strongly in fire events compared with traditional timber house construction and provides high-strength fire performance for Monterey Kangaroo Point.
Studies have suggested that timber buildings contribute to the improvement of emotional state and self-expression. Timber used for Monterey Kangaroo Point will be visually warm and engender a socially positive experience for building occupants.
Air quality and humidity has been calculated to improve due to the timber building environment, and this may contribute to easier breathing, lower stress levels and feelings of warmth and comfort for those who reside in the building. It will be a key part of Brisbane’s sustainable future.