Portland project uses Oregon-made CLT
PORTLAND, Ore. – Advanced wood products are making a major breakthrough this month, with the first use of U.S.-produced cross-laminated timber panels in a building-wide structural system. The CLT panels are being installed at Albina Yard, a creative office development in north Portland.
The second of four installations of Oregon-made CLT panels on the project will occur early next month. The third tier of panels is scheduled to be installed a few weeks later, according to the project’s developer and contractor, Portland-based Reworks Inc.
Construction on the 16,000-square-foot creative office building in the vibrant Mississippi District began last fall and is expected to be completed by July.
The building owner is Albina Yard LLC. The project architect is LEVER Architecture, and the structural engineer is KPFF Consulting Engineers.
Albina Yard’s unique design incorporates mass timber construction with a glue-laminated timber frame and CLT panels fabricated at D.R. Johnson Lumber Co. in Riddle, Ore. D.R. Johnson is currently the only U.S. manufacturer of CLT panels certified for use in structural applications. The glulam timber frame is on a 10-foot-by-25-foot grid with concealed steel connectors.
The wood columns, beams, girders and CLT panels were all prefabricated offsite to 1/8-inch tolerances using advanced computer-aided design (CAD) technology and CNC machinery, including a Hundegger K2-ROBOT six-axis joinery machine.
The prefabrication, by Cut My Timber in Portland, results in building components that are sawn to size with pre-bored holes, and slats routed to tight tolerances to neatly fit to the connectors. This allows the components to be assembled on site in a fraction of the time normally required.
At Albina Yard, the first CLT installation earlier this month took just four hours to install 4,000 square feet. That much framing would normally have taken a week or more using traditional methods.
“The building design reveals the material qualities that are inherent to these new and innovative mass timber technologies,” says Thomas Robinson, founder of LEVER Architecture. “Because of the strength of the CLT panels, we are able to span longer distances with fewer beams and employ large angled cantilevers that give the building façade a dynamic presence.”
Using wood also gives the building a lighter environmental impact than other common building materials. Numerous life cycle assessment studies show that wood products outperform steel and concrete in terms of embodied energy, as well as air and water pollution produced. Wood also has better thermal performance properties than common alternatives, making it more energy efficient. And wood is the only common building material derived from a renewable resource.
Additionally, wood products have a significantly smaller carbon footprint, because they store carbon. As trees grow, they absorb carbon dioxide from the atmosphere, storing the carbon in wood fiber and releasing oxygen. The stored carbon remains in the wood after the trees are converted to wood products, and the cycle starts over when new trees are planted to replace those that were harvested.
Albina Yard incorporates approximately 161,000 board feet of solid wood products and 19,550 square feet of wood panel products, with a combined storage of some 80.5 metric tonnes of carbon – the equivalent of offsetting 295 metric tonnes of CO2 emissions.
“We see Albina Yard as a catalytic project, paving the way for broad market adoption of mass timber construction in Portland and throughout the country,” says Aaron Blake, principal of Reworks and Albina Yard, LLC. “Mass timber products derived from sustainably managed forests allow us to build faster, stronger and less expensively with fewer environmental costs. Albina Yard is a proving ground for this new building technology, giving design teams and construction crews an opportunity to gain expertise that can be applied to much larger projects.”
Lessons learned in the design and construction of Albina Yard will be applied to Framework, a 12-story wood building being planned for Northwest Portland by a team consisting of LEVER Architects and Project^. When completed, Framework is expected to be the tallest wood building in the U.S. It recently earned a $1.5 million prize in the Tall Wood Building Design Competition from the U.S Department of Agriculture.
Valerie Johnson, president of D.R. Johnson Lumber in Riddle, Ore., sees great promise for the state’s rural communities in these advanced wood products.
“Tall wood buildings have a great environmental story, and advanced wood products make better use of our state’s greatest natural resource,” she says. “Greater use of these products in taller wood buildings means more jobs for rural communities that have been experiencing economic decline for years.”
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