by Web Editor | Aug 21, 2017 | News
Ever since the 10-story Home Insurance Building in Chicago was called the first “skyscraper” in 1885, architects have been striving to create ever-taller buildings. Ten stories quickly became 20, 20 became 50, and on and on. In 2009 the Burj Khalifa in Dubai became the world’s tallest building, with its 154 floors towering above ground level.
So why is the mayor of Portland, Oregon, calling a modest 12-story tower set for completion there next year “a true technological and entrepreneurial achievement?” It’s not the affordable housing the building affords, nor its dozens of bike racks or even the roof farm that has Ted Wheeler gushing. It’s that the Framework apartment building will be made almost entirely of wood.
Once completed, Framework will be America’s tallest wooden building and its first “plyscraper” — a high-rise building built with panels made of cross-laminated timber (CLT). These modular sheets are made from cheap, sustainable softwood that are glued or pinned together in layers — a bit like super-strong, super-thick plywood.
While the raw material might vary in quality, CLT (also known as mass timber) is engineered to be stronger than concrete. CLT panels resist earthquakes and even fire, charring instead of catching alight like the lumber in typical homes.
Plyscrapers can be bolted together in days, and they require a fraction of the labor use to erect traditional steel-and-concrete high-rises. “You don’t need an experienced master carpenter to do this,” says Casey Malmquist, founder of Columbia Falls, Montana-based SmartLam, one of only two CLT manufacturers in the U.S. “It literally goes together like Legos.”
From NBC News: https://www.nbcnews.com/mach/tech/eco-friendly-plyscrapers-are-rise-here-s-why-ncna793346
by Web Editor | Jan 18, 2017 | News
Mass timber is sprouting up in cities in North America and abroad. After years of feasibility studies and design proposals, buildings six stories or taller constructed primarily from pre-engineered wood products are being considered in cities around the world.
In London, one proposal, called the Splinter, would rise to 100 stories. In Chicago, Perkins+Will (in collaboration with Thornton Tomasetti and the University of Cambridge) has designed an 80-story high-rise with 300 duplex apartments. If built, River Beech—a key component of P+W’s master plan for the Riverline development—would be made almost entirely from mass timber.
So-called “plyscrapers” are still a tiny sliver of nonresidential construction. In the past five years, only 17 buildings seven stories or taller have been completed worldwide, mostly in Europe and Canada. Six more have started construction, according to the American Wood Council.
Mass production of timber for high-rise construction is still in its infancy in North America. Specifying these products in the U.S. faces resistance from insurers, regulators, and code officials. Steel fabricators and concrete suppliers disparage mass timber for taller buildings on the grounds of safety and durability.
Proponents cite the speed at which tall buildings can be constructed using pre-engineered wood and mass timber’s ability to sequester carbon. Joey-Michelle Hutchison, RA, LEED AP BD+C, CSBA, Associate Vice Principal, CallisonRTKL, says, “The role of mass wood is going to grow because of the demand for sustainable design.” Researchers from Yale and the University of Washington, in a study published in the Journal of Sustainable Forestry (March 28, 2014), postulated that using wood substitutes for constructing buildings (and bridges) could save 14–31% of global CO2 emissions.
From Building Design + Construction: https://www.bdcnetwork.com/mass-timber-what-heck-wow
