Austria’s Pyramidenkogel: ‘at a height of 100 metres it is the tallest wooden observation tower in the world’ says Wikipedia [image credit: Rollroboter @ Wikipedia]
Another case of jumping on the climate bandwagon to promote a product? The term used is ‘mass timber’, or engineered wood. Sweden has already built the first wooden wind turbine tower, made of modular laminated wood.
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Architects and engineers are working on ways to swap steel and glass for strong, sustainable wood-based materials, says Discover Magazine.
When the empire state building was completed in 1931, the 102-story skyscraper ranked as the tallest in the world, a beacon of American progress as well as a lightning rod for Midtown Manhattan.
And the material that made it possible was steel — or so people believed until 2015, when Canadian architect Michael Green showed that an identical structure could be fabricated out of timber.
Green was not proposing replacing the 20th-century icon. His plans are far more radical. Green wants the global construction industry to replace steel and concrete with high-tech plywood.
“We’re not even close to meeting global needs when it comes to housing people in a safe and affordable way,” he says. Plus, the construction of buildings is responsible for around 10 percent of all global climate emissions.
Green claims that these interrelated problems can both be addressed by building with timber from sustainably grown forests. To show the high-reaching potential of wood in the real world, in 2016 he erected a seven-story high-rise in Minneapolis, the tallest wooden building in the U.S. at the time.
He used a plywood popularized in the 1990s. Losing market share to concrete, the lumber industry had sought to produce a material that would be both sturdy and cheap.
By gluing stacks of wood panels together into massive blocks they called “mass timber,” the engineers effectively replicated traditional masonry.
And they added several features that neither stone nor concrete could claim: The new material could be cut with high precision, making it suitable for affordable, high-efficiency prefabrication. Plus, it was relatively light, making it practical to transport from a factory to the construction site.
But what most impressed Green was the strength: When the wood panels are cross-laminated, or glued with their grains running in alternating directions, the material is, pound for pound, stronger than steel.
Wooden buildings actually have the potential to roll back climate change, says Green, because trees soak up carbon and incorporate it into their wood as they grow. “You’re holding on to that carbon until [the wood] burns or rots.” And unlike ordinary lumber, mass timber is highly resistant to fire.
These arguments are catching on with other builders, who are making their own wooden high-rises higher and higher. The current record is an 18-story tower in Norway. An 80-story skyscraper is planned for London.
Continued here.
via Tallbloke’s Talkshop
June 2, 2020 at 01:27PM
Iowa Climate Science Education 