by Web Editor | Oct 11, 2017 | News
As a crane lowered a glulam beam and construction workers on either end deftly guided it into connection with two upright wooden columns, a tour group member shook his head and said, “It’s like Lincoln Logs.”
Kind of. Which may in part explain some of the attraction of builders and designers to the potential use of strong, precisely engineered, carbon-storing wood beams, columns, wall panels and floor decking. As Chris Evans, a Swinerton Builders project manager put it, wood is the first building material people use to make the forts, homes and hideouts of childhood.
These days, builders and designers are joining mill owners, university researchers and policy makers in taking a fresh look at advanced wood products, “mass timbers” and what’s come to be called “tall wood” design. Advocates believe it can replace concrete and steel in mid- to even high-rise buildings, and provide an economic jolt to rural Oregon in terms of forest management and mill jobs.
In Hillsboro, Evans and Swinerton Builders are overseeing construction of the largest known U.S. building to date that uses cross-laminated timber, or CLT, for flooring, and glulam posts and beams. The Oregon headquarters of First Tech Credit Union will be five stories high and have 156,000 square feet of office space. Swinerton Builders is the general contractor.
Another tall wood building planned for Portland, called Framework, will be 12 stories high and will have five floors of affordable housing. That project was awarded a $1.5 million federal design competition grant to help with seismic and fire testing and certification.
From Capital Press: https://www.capitalpress.com/Oregon/20171005/nations-largest-mass-timber-building-under-construction-in-oregon
by Web Editor | Jul 19, 2017 | News
The International Code Council Ad-hoc Committee on Tall Wood Buildings provided five fire scenarios that were tested in each of the two one-bedroom apartments constructed using mass timber in a multi-story apartment building. The test scenarios included various arrangements of exposed and unexposed cross-laminated timber (CLT) with open doors between living and sleeping areas while the effectiveness of automatic sprinkler systems was simultaneously evaluated.
Test 1: a mass timber structure fully protected with gypsum wall board was subjected to a large furnishings and contents fire. The test was terminated after three hours without significant charring on the protected wood surfaces of the structure.
Test 2: approximately 30 percent of the CLT ceiling area in the living room and bedroom were left exposed. The test was terminated after four hours, providing additional time to determine if there would be any significant fire contribution from the exposed CLT. Notably, once the furnishings and contents had been consumed by the fire, the exposed CLT essentially self-extinguished due to the formation of char that protected the underlying wood.
Test 3: parallel CLT walls were left exposed, one in the living room and one in the bedroom. Similar to Test 2, once the apartment furnishings and contents had been consumed by the fire, during which a protective surface of char formed on the CLT, the mass timber surfaces essentially self-extinguished.
Test 4 and 5: examined the effects of sprinkler protection. For both tests, all mass timber surfaces in the living room and bedroom were left exposed. Test 4 demonstrated that under normal operating conditions, a single sprinkler easily contained the fire. For Test 5, the fire was allowed to grow in the compartment for 23 minutes before water was supplied to the sprinklers which quickly controlled the fire.
From Woodworking Network: https://www.woodworkingnetwork.com/architectural-products/cross-laminated-timber-fire-testing-sees-promising-results?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
