Engineered timber products are enabling buildings made from wood to rise to unprecedented heights in the 21st century.
Toward the end of last year, construction commenced in the Canadian province of British Columbia on what is slated to be the world’s tallest timber building upon completion.
The Brock Commons student residence at the University of British Columbia will stand 53 metres in height comprising a total of 18 storeys, making it the modern era’s tallest building made from wood.
That will make it more than 21 metres taller that Melbourne’s 10-storey Forte apartment complex, which at 32 metres in height is believed to be the reigning title holder.
The CA$51.5 UBC student residence was designed by Acton Ostry Architects in collaboration with Austrian “tall wood advisor” Architeckten Hermann Kaufmann, and is expected to host over 404 student tenants upon its completion in mid-2017.
One of the objectives of the project’s developers is to prove that mass timber buildings are a safe and viable option for modern construction at greater heights, given the range of new products that possess enhanced strength and fire-resistance.
Engineered timber products which have become increasingly widespread since the turn of the century include cross laminated timber (CLT), laminated veneer lumber (LVL) and glued laminated wood (glulam). The heightened resilience of these timber materials enables modern buildings made from wood to surpass the traditional height threshold of between three to six storeys.
Brock Commons will consist of a hybrid structure of CLT floor slabs and glulam columns augmented by steel connectors and concrete cores.
Cross laminated timber consists of multiple timber layers called lamellas which are glued together to form panels. The grain of each layer runs perpendicular to those of the adjacent layers, conferring the material with heightened strength and properties more akin to those of pre-cast concrete panels.
Glulam is a similar engineered timber product, consisting of laminates of uniform thickness that are glued together to form individual structural members such as vertical columns, horizontal beams, or even arches.
One of the keys to the enhanced fire resistance of these products is their ability to use the natural charring propensity of heavy timber to muffle the spread of any incipient blazes.
The charring process occurs at a steady and predictable rate when the timber is exposed to high heat levels, and results in the creation of an insulating layer that delays heat increases at the core.
According to Robert Gerard, fire engineer with Arup and co-author of the 2013 Fire Safety Challenges of Tall Wood Buildings report commissioned by the US National Fire Protection Association, timber products capable of undergoing the charring process are safe and viable options for construction at greater scales.
“From an engineering perspective, taking advantage of the charring behavior of wood is another means of enhancing the fire safety of timber building materials,” he said. “The solutions already exist to create safe, multi-story timber structures.”
Tall timber construction appears to be gaining traction rapidly around the world, with other large-scale projects in the works including a 10-storey residential tower in Manhattan designed by SHoP Architects in collaboration with engineering giant Arup.
While Brock Commons could be the tallest timber building in the world upon its completion in 2017, it’s unlikely to retain that title for long given the ambitions of other architects to create wooden skyscrapers running to greater heights.
In June 2015 Vancouver-based architect Michael Green unveiled a design proposal for a timber tower in Paris that would dwarf Brock Commons. The design for the “Baobab” complex, submitted to the Reinventer Paris design competition, envisages the creation of a timber high-rise in the French capital that will reach a total height of 35 storeys.
Architects in Austria are also angling for the title of world’s tallest wooden building, with plans for a 84-metre timber development in Vienna’s Seestadt Aspern urban development area.
The HoHo project would see the creation of mixed-use high-rise building that houses offices and residential apartments, as well as a hotel, fitness centre and restaurants. If given the green light by local fire authorities, approximately 75 per cent of the structure of the HoHo Vienna from the ground floor up will consist of engineered timber products.