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 | Jun 7, 2017 | News
Officials in Oregon have approved construction permits for the first all-wood high-rise building in the nation. Construction on the 12-story building, called Framework, will break ground this fall in Portland’s trendy and rapidly growing Pearl District and is expected to be completed by the following winter.
The decision by state and local authorities to allow construction comes after months of painstaking testing of the emerging technologies that will be used to build it, including a product called cross-laminated timber, or CLT.
To make CLT, lumber manufacturers align 2-by-4 boards in perpendicular layers and then glue them together like a giant sandwich before sliding the resulting panels into a massive press for drying. The resulting panels are stronger than traditional wood because of the cross-hatched layers; CLT can withstand horizontal and vertical pressures similar to those from a significant earthquake with minimal damage. They also are lighter and easier to work with than regular timber, resulting in lower cost and less waste.
For this project, scientists at Portland State University and Oregon State University subjected large panels of CLT to hundreds of thousands of pounds of pressure and experimented with different methods for joining them together. The project materials also underwent extensive fire safety testing and met fire codes.
State officials hope the building will stir greater interest in high-rise construction using mass timber and help revitalize the state’s lagging logging industry. Logging, once a major source of revenue in Oregon, has dropped sharply in the past few decades because of greater environmental protections for salmon and the spotted owl. The loss of the industry has devastated some of the state’s rural communities.
From The Register-Guard: https://registerguard.com/rg/news/local/35651365-75/portland-approves-permit-for-nations-first-all-wood-high-rise.html.csp
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 | Aug 31, 2016 | News
In Vancouver, Canada, the towering timber Brock Commons just had its final panel installed, making the dream of the world’s tallest timber building a reality, reports the website Inhabitat.
In just 66 days – ahead of the original scheduled timeframe – the exterior of the Acton Ostry Architects‘ record-breaking design has come to fruition, which could bump up the projected fall 2017 completion date to next year’s spring semester. The final panel of the University of British Columbia student housing structure was lifted and installed earlier this month.
John Metras, managing director of UBC Infrastructure, said, “Construction just went really smoothly. It was well designed and the construction sequence went smoothly.”
Construction began last November, followed by the erection of the building’s freestanding concrete cores earlier this year.
To ease fire safety fears of an 18-story timber structure, Brock Commons is outfitted with a sprinkler system and the wood is encapsulated in drywall and concrete. The lighter weight of the building also allows for better energy dissipation during an earthquake, making it proficient at withstanding all kinds of disasters. Students will be able to move in next year, quite possibly in the spring semester.
From ProudGreenBuilding: https://www.proudgreenbuilding.com/news/worlds-tallest-timber-building-topped-off-ahead-of-schedule/
