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 | Jul 17, 2017 | News
A two-story cross-laminated timber (CLT) structure is being subjected to the forces produced by a 1994 6.7 Northridge earthquake. The engineered simulation is expected to reveal ways in which tall wood buildings could survive damaging earthquakes.
Workers constructed a 22-foot tall wood test structure on UC San Diego’s shake table, a device for shaking structural models or building components with a wide range of simulated ground motions, like earthquakes.
Led by the Colorado School of Mines (CSM), the new test will examine the viability of constructing quake-resistant CLT buildings that could be as tall as 20 stories high.
“We are working to minimize the amount of time buildings are out of service after large earthquakes,” CSM engineer Shiling Pei said in a statement. “We are also focused on cutting the costs required to repair them.”
Cross-laminated timber advocates say it can be used to construct buildings of equal strength and fire-resistance as those made of steel and concrete. It has also fueled the passions of architects and environmentalists, who believe it to be a much greener method for housing the world’s growing population.
From Woodworking Network: https://www.woodworkingnetwork.com/two-story-cross-laminated-timber-simulated-67-earthquake?ss=news,news,woodworking_industry_news,news,almanac_market_data,news,canadian_news
by Web Editor | Apr 5, 2017 | News
The U.S. Forest Service is working to build markets for innovative forest products. One of these products, cross-laminated timber, also known as CLT, offers an opportunity for raising tall buildings with wood, opening up a completely new market for wood products.
And there’s tremendous opportunity to increase the market share for wood-based construction. Because of its high strength, CLT is an advantageous alternative to traditional building materials such as concrete, masonry, and steel. Because CLT panels resist compression, they are well-suited for building multistory structures, especially mid-rise buildings. Made from layers of dried lumber boards, stacked in alternating direction at 90-degree angles, glued and pressed to form solid panels, CLT has exceptional strength and stability and can be used as walls, roofs, and floors.
Additionally, CLT is highly resilient to fire, earthquakes, and even explosions. In fact in a recent series of live blast tests, CLT passed with flying colors. An examination of the results showed that the CLT structures suffered less degradation than expected and might outlast concrete and steel.
In terms of fire, CLT is like using a large log to start a campfire—it doesn’t ignite easily. And when it does burn, a char layer forms on the outside, protecting the inside and allowing the wood panel to maintain its structural integrity during fire scenarios.
Researchers have conducted extensive seismic testing on CLT and found that the panels perform exceptionally well in multi-story applications. When a seven-story CLT building was tested on the world’s largest shake table in Japan, it survived 14 consecutive earthquake simulations with almost no damage.
From the USDA: https://www.usda.gov/media/blog/2017/04/04/build-better-stronger-faster-clt
by Web Editor | Jan 4, 2017 | News
When the 12-story Framework building planned at Portland’s Northwest 10th Avenue and Glisan Street is complete, it may look to passers-by like any other Pearl District condo tower.
But it will hold a special distinction in the sustainable building world: the nation’s tallest building made primarily from mass timber (long pieces of timber, glue-laminated together).
Designers and engineers across the country are chasing an innovative style of mass timber construction pioneered in Europe, which they believe will go a long way to reduce the carbon footprint of large buildings.
The breakthrough came with the development of cross-laminated timber or CLT: Large, layered flat panels used as floors and walls (rather than just beams as vertical posts).
As Oregon moves on multiple fronts to take the national lead in all-wood construction for tall buildings, Portland State University stepped up early to do basic research. PSU won a three-year, $400,000 National Science Foundation grant to study two aspects of mass timber construction: its sustainability and how well it resists earthquakes.
From Sustainable Life: https://pamplinmedia.com/sl/337694-214716-psu-tests-new-green-woods-seismic-strength
