by Web Editor | Oct 31, 2018 | News
Prescriptive requirements for wood structures up to 18 stories were among the additions preliminarily approved for the International Building Code following the work of the International Code Council’s ad-hoc Tall Wood Buildings Committee.
Wood is widely recognized as a carbon-neutral building material, but its use as a structural material has been mostly limited to residential and low-rise buildings due to its combustible nature. Through recent advances in manufacturing and engineering, wood in the form of mass timber products is increasingly attracting interest as a structural system for tall buildings.
Portland, Ore., recently saw the completion of the eight-story Carbon12, currently the tallest wood building in the United States. Still, progress has been slow in this country as compared to Europe or Canada, where the 18-story-tall Brock Commons, in Vancouver, stands as the tallest timber structure in the world. One significant issue inhibiting widespread adoption in the U.S. is prescriptive building codes, which currently limit the height of wood buildings to 85 feet, or six stories. In December 2015, the International Code Council (ICC) formed an ad-hoc committee to study the impact of tall wood buildings on the building code with the membership voting on the adoption of proposed changes on Oct. 24.
The ICC’s International Building Code (IBC) classifies a high-rise building as any building with an occupied floor 75 feet above the lowest level at which fire department vehicles can access. The 2018 IBC defines heavy timber structural members as Type IV construction, which also includes a range of wood products, such as solid sawn timber, glue-laminated members, and composite wood members. The term mass timber, however, comprises both heavy timber as well as engineered products, many of which the IBC does not reference, such as cross-laminated timber (CLT).
Heavy timber construction is currently limited to a height of 85 feet. Architects can design taller wood structures, but they must demonstrate that the design meets the prescribed code and performs as well or better than a similar concrete or steel structure. This can be a costly and time-consuming process, requiring extensive testing and documentation on the part of the design team and building owner.
Read more on this from Architect Magazine at https://www.architectmagazine.com/technology/support-for-tall-timber-reaches-new-heights-in-the-building-code_o.
by Web Editor | Aug 6, 2018 | News
The state legislature earlier this year called on the Washington State Building Code Council (WSBCC) to adopt rules for cross-laminated timber (CLT) use when building residential and commercial buildings. The move represents ongoing efforts to bring CLT into mainstream use for residential and commercial construction, which would create commercial value for the small-diameter trees that are contributing to poor forestland health in Washington state.
For state and federal officials, as well as private stakeholders, that change could hasten restoration work by making tree thinning a profitable endeavor rather than a costly project requiring government funding.
The potential CLT offers was articulated by U.S. Forest Service (USFS) Chief Vicki Christiansen at the 2018 Pacific NorthWest Economic Region Summit in Spokane on July 24. “We can use new opportunities for forest product delivery to help us to improve forest conditions, while also creating jobs and sustaining rural communities. We can implement these new practices by working together and being a good neighbor.”
Forest Service Region 6 covers Washington and Oregon and includes 28 percent of all forestland across Washington. In recent years the federal agency has struggled to conduct forest health work due to “fire borrowing” in which those portions of its budget are used to pay for the high cost of firefighting. During last year’s wildfire season USFS spent $2 billion on wildfire fighting, more than half its budget. There were 50 large fires on USFS land and over 411,000 acres burned, costing the agency $130 million. Over 90 percent of those fires were human-caused. In April, federal legislation sought to end the practice of fire-borrowing by allocating additional long-term funding to USFS to the tune of $2 billion starting in 2020.
A 2014 analysis by The Nature Conservancy and USFS concluded that half a million acres of forestland managed by the federal agency in Eastern Washington were in need of thinning and prescribed burns. Along with the new funding, Christiansen said that they can also “align our best practice policies and guidance with the changing markets that are certainly emerging in the Pacific Northwest.”
Read more on this from The Lens at https://thelens.news/2018/07/31/cross-laminated-timber-as-forest-management-strategy/.
by Web Editor | Oct 30, 2017 | News
Oregon and Southwest Washington are well-positioned to become a manufacturing hub for cross-laminated timber — an innovative building product sometimes called “plywood on steroids” — according to a new study prepared by Oregon BEST.
The 110-page analysis found Oregon has the potential to create 2,000 to 6,100 direct jobs making cross-laminated timber and related mass timber products, which use adhesives and layered wood to create massive panels used as walls, floors and roofs, or beams. Mid-rise office and residential buildings are now being made with CLT, providing a dramatically lower carbon footprint than buildings using concrete and steel. Some high-rise projects using CLT are in the works.
Studies show CLT also cuts costs, mostly because construction takes less time. That cost advantage is projected to grow. “The cost of wood as a building material and as the raw material for CLT is expected to stay stable in the near future, while concrete and steel prices are forecast to raise with their relative energy prices and carbon costs,” the report states.
Oregon BEST, which commissioned the study along with partners, is a state-supported nonprofit that works closely with academia to nurture the state’s clean-tech industry.
CLT was developed in Europe, and European and Canadian companies got into the field before their U.S. counterparts. But D.R. Johnson became the first U.S. company certified to manufacture CLT in 2015, and is making it at its Southern Oregon plant in Riddle.
From Sustainable Life: https://pamplinmedia.com/sl/376727-262480-plywood-on-steroids-holds-great-potential-for-oregon-economy-environment
