by Web Editor | Feb 13, 2017 | News
The new Brock Commons student residence at the University of British Columbia will be the tallest contemporary mass timber building in the world when finished this May. The term “mass timber” or “mass wood” covers an array of approaches, usually referring to a structural system combining engineered wood columns and floor slabs. In Canada, the most commonly referenced technical innovation, and one of the ones behind Brock Commons’ structure, is the cross-laminated timber (CLT) slab, available in a variety of thicknesses for different span requirements.
While Brock Commons’ height will unquestionably get the lion’s share of attention after its completion, that’s not the most interesting thing about the building for architects. Rather, it is the fact that, on typical floors, the wood is not visible.
Acton Ostry Architects principal Russell Acton, FRAIC, the lead designer of Brock Commons, has lectured widely on the project. When he talks to architectural audiences, he is inevitably asked: “why didn’t you expose the wood?” The answer is that the wood structure has been encapsulated in drywall and concrete topping to ensure efficient code compliance.
This pragmatic approach was a response to achieving quick approvals, and as an associated outcome, addressed perceptual challenges in terms of fire safety. In fact, the historic (and completely understandable) fear of fire in wood frame buildings is dramatically less relevant to mass timber. During a fire, the outside surface of a thick wood member chars while protecting a structural core of unburnt wood. As building codes develop, it is likely that the testing of mass wood assemblies will assist authorities to better understand the inherent fire resistance of mass timber, and potentially reduce the need for encapsulation, provided that a sacrificial layer of wood char is provided in its place.
From Canadian Architect: https://www.canadianarchitect.com/features/reaching-new-heights-2/
by Web Editor | Jan 18, 2017 | News
Mass timber is sprouting up in cities in North America and abroad. After years of feasibility studies and design proposals, buildings six stories or taller constructed primarily from pre-engineered wood products are being considered in cities around the world.
In London, one proposal, called the Splinter, would rise to 100 stories. In Chicago, Perkins+Will (in collaboration with Thornton Tomasetti and the University of Cambridge) has designed an 80-story high-rise with 300 duplex apartments. If built, River Beech—a key component of P+W’s master plan for the Riverline development—would be made almost entirely from mass timber.
So-called “plyscrapers” are still a tiny sliver of nonresidential construction. In the past five years, only 17 buildings seven stories or taller have been completed worldwide, mostly in Europe and Canada. Six more have started construction, according to the American Wood Council.
Mass production of timber for high-rise construction is still in its infancy in North America. Specifying these products in the U.S. faces resistance from insurers, regulators, and code officials. Steel fabricators and concrete suppliers disparage mass timber for taller buildings on the grounds of safety and durability.
Proponents cite the speed at which tall buildings can be constructed using pre-engineered wood and mass timber’s ability to sequester carbon. Joey-Michelle Hutchison, RA, LEED AP BD+C, CSBA, Associate Vice Principal, CallisonRTKL, says, “The role of mass wood is going to grow because of the demand for sustainable design.” Researchers from Yale and the University of Washington, in a study published in the Journal of Sustainable Forestry (March 28, 2014), postulated that using wood substitutes for constructing buildings (and bridges) could save 14–31% of global CO2 emissions.
From Building Design + Construction: https://www.bdcnetwork.com/mass-timber-what-heck-wow
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
by Web Editor | Feb 10, 2016 | News
Last month we saw cross-laminated timbers installed at the Albina Yard project in Portland. It was the first use of U.S.-produced CLT in a building-wide structural system.
The first level of CLT (4,000 square feet) on Albina Yard went up in fewer than four hours. Last week, the second level was installed by a crew of seven in under two hours. Pretty remarkable, considering the contractor says it would have taken at least twice as many people two days or more to frame the same amount of floor space using traditional methods. Albina Yard is a four-story, 16,000-square-foot creative office project in north Portland. Besides its snazzy design by LEVER Architecture, the project is most notable for being tangible evidence that the U.S. CLT industry is officially off the ground.
There’s been a lot of buzz around CLT and mass timber in general over the past several months in Oregon and around the country — and rightly so. Besides drastically improved speed of construction (and the savings that go with that), mass timber offers significant environmental benefits. This includes tremendous carbon-storing capacity. Half the dry weight of wood is carbon. It got there when the trees were growing and absorbing carbon dioxide from the atmosphere. That carbon remains locked up for as long as the wood remains in use (a nine-story wood structure in China is now 959 years old—nearly a millennium). The new trees planted to replace those that were harvested start the carbon cycle all over again.
According to a quick, back-of-the-napkin calculation, Albina Yard, which is small by commercial construction standards, stores about 80.5 metric tons of carbon. That’s equivalent to offsetting 295 metric tons of CO2 emissions.
A larger Portland mass timber building, Clay Creative (60,000 square feet), stores more than 1 million pounds of carbon. Its total of 457.5 metric tons offsets 1,678 metric tons of CO2 emissions. “An additional 3,574 metric tons of CO2 emissions were avoided by using wood rather than concrete and steel,” says Dr. Jim Bowyer, an expert on the subject at Dovetail Partners, Inc.
From the Oregon Forest Resources Institute: https://oregonforests.org/blog/mass-timber-rising
