Subsequent in our Timber Revolution sequence is a profile of Mjøstårnet, an 85.4-metre-high tower in Brumunddal, Norway, that was one of many world’s first true timber skyscrapers.
The 18-storey mixed-use constructing was named world’s tallest timber constructing by the Council on Tall Buildings and City Habitat (CTBUH) when it was accomplished in March 2019, comfortably surpassing the 53-metre Brock Commons Tallwood Home in Vancouver.
Structure studio Voll Arkitekter believes that the milestone demonstrated what the way forward for sustainable structure may appear like.
“Wooden building has gained a brand new renaissance and we’re proud to have the ability to assist wood structure attain new heights,” Voll Arkitekter accomplice Øystein Elgsaas informed Dezeen.
“Mjøstårnet is just not the blueprint of a tall timber constructing however a contributor to additional sustainable growth,” Elgsaas added.
“Sustainable-wise, a very powerful side of our constructing was to indicate that it’s attainable to construct giant, complicated timber buildings, and in that trend, encourage others to do the identical.”
Positioned on the shore of Norway’s greatest lake, Mjøsa, which lends its identify to the constructing, the 18-storey tower comprises flats, a resort, workplace house and a restaurant.
It was constructed utilizing two forms of engineered wooden: cross-laminated timber (CLT) and glue-laminated timber – often known as glulam. As a result of each sorts of wooden are fashioned of layers of lamellas glued collectively crosswise, they’re considerably stronger than normal wooden.
Massive glulam trusses constructed from light-coloured spruce wooden assist the construction alongside its facades in addition to forming its inside columns and beams. In the meantime, CLT was used to assist the constructing’s three elevators and two staircases.
The structural mass timber was left uncovered inside, making the tower fast to construct. The groundwork for the undertaking started in April 2017 and the primary timber building came about simply six months later.
The studio was significantly eager to make use of timber due to its sustainability credentials. Timber act as carbon sponges, absorbing atmospheric carbon which is then locked up within the wooden and saved within the constructing.
Wooden can also be much less carbon-intensive to fabricate, transport and assemble than concrete, which means that the manufacturing course of has decrease embodied carbon emissions. The embodied carbon from buildings made from metal and concrete quantities to 11 per cent of worldwide carbon emissions.
“Wooden is a greater possibility than concrete with regards to the carbon storage within the materials itself,” stated Elgsaas.
“The place you historically want a big quarry to supply the fabric for the concrete manufacturing, it leaves giant scars within the atmosphere that do not ‘heal’ in the identical approach as a big space used for harvesting bushes does,” he continued.
“A sustainably managed forest and harvesting of the bushes would really profit the realm’s organic range.”
Norwegian legislation requires forest homeowners to make sure harvested areas are “regenerated inside three years”.
Brumunddal’s proximity to a significant forestry and wooden processing hub meant that the supplies for Mjøstårnet have been sourced from close by spruce and pine forests.
“The spruce used within the building of the glulam components, resembling trusses, columns and beams, have been sourced regionally within the space of Ringsaker,” Elgsaas recalled.
“The timber is minimize to plain board measurement planks on the native sawmill after which processed at Moelven, the place they make the ultimate glulam merchandise used within the building,” he added. “Moelven is only a fifteen minutes drive from Brumunddal.”
Scandinavia’s entry to giant woodlands provides it an abundance of native wooden assets, fuelling a surge in architects turning to wooden for initiatives within the area.
Among the many notable tall timber initiatives in Nordic nations is Sweden’s Kajstaden Tall Timber Constructing by CF Møller Architects and Finland’s tallest wood condo block, Puukuokka, by OOPEAA.
In accordance with Elgsaas, the timber trade has modified since Mjøstårnet was constructed and public scepticism over the potential of timber for tall buildings has subsided.
“The deal with the atmosphere and the advantages of utilizing wooden has modified dramatically since we started our undertaking again in 2015,” he stated.
“Folks have found the likelihood and advantages of utilizing completely different constructing supplies and that there isn’t any longer a predetermined answer to what a bigger and extra complicated constructing might be constructed from.”
Though the studio was dedicated to utilizing timber, the fabric didn’t come with out its points. The inherent lightness of timber proved difficult for the architects as a result of the highest of the constructing was susceptible to shifting within the wind.
“Peak accelerations as a result of wind on the highest flooring of Mjøstårnet is on the restrict of what’s acceptable for residential buildings,” stated Elgsaas.
“The acceleration within the motion is faster than in a heavier constructing of metal and concrete and if not saved inside the required ranges, it may result in nausea.”
Architects create composite buildings – wood-concrete-hybrid buildings or timber frames with concrete cores to keep away from this downside. Nevertheless, Voll Arkitekter determined to include concrete inside Mjøstårnet’s flooring to offer it the required sturdiness and weight.
“We elevated the load on the higher flooring: flooring 12 to 18 are 300 millimetre-thick concrete made from a precast aspect on the backside and an in-situ layer of topping concrete,” Elgsaas defined.
“Changing wooden flooring with concrete flooring on the higher flooring meant that the constructing could be heavier in the direction of the highest and that might decelerate the acceleration within the motion of the constructing when affected by wind forces.”
In 2022, Mjøstårnet was overtaken because the world’s tallest timber constructing by Ascent, an 86.6-metre-tall tower in Wisconsin, which was designed by Korb + Associates Architects.
An all-timber constructing is classed as such by the CTBUH if each the primary vertical or lateral structural components and the ground are constructed from timber.
Ascent is unlikely to carry the highest spot for lengthy, as a 100-metre-tall housing block in Switzerland timber constructing by Danish studio Schmidt Hammer Lassen is ready to turn into the world’s tallest when it completes in 2026.
The images is by Ricardo Foto until said in any other case.
This text is a part of Dezeen’s Timber Revolution sequence, which explores the potential of mass timber and asks whether or not going again to wooden as our major building materials can lead the world to a extra sustainable future.