by Web Editor | Jan 29, 2018 | News
New mass timber products are becoming more widespread and encouraging builders, designers, and engineers to search for the best applications for mass timber initiatives. A few of the mass timber building products available today include:
• Cross-laminated timber
• Nail-laminated timber
• Glue-laminated timber
• Dowel-laminated timber
As they test the capabilities of these materials, designers are looking to existing mass timber buildings around the world for examples and inspiration.
Canadian and European researchers and architects began experimenting with the design of mass timber buildings in the 1970s. European timber projects have shown that weight matters with structural systems, and mass timber structures weigh up to one-third as much as their concrete counterparts. This fact has made wood construction a viable prospect in places where building height and weight are limited, such as city utilities, subway tunnels, and underground rail yards.
Due to their lighter weight, mass timber buildings are more resilient in seismic zones. They carry less inertia, so the possibility of destructive swaying goes down. This approach was recently applied in the Brock Commons tower, an 18-story college residence designed for the University of British Columbia by Canadian firm Acton Ostry Architects.
The 173-foot-tall tower combines glue-laminated columns, cross-laminated timber floor slabs, dual concrete cores, and steel connectors. The cores help to counteract wind-generated and seismic forces while anchoring the mass timber building in place. It meets structural and fire-safety regulations by utilizing a specially designed set of interdependent finishes and building materials.
From CRL: https://c-r-l.com/content-hub/mass-timber-buildings-credibility/
by Web Editor | Jun 13, 2017 | News
Timber construction is opening a new market that has been keeping lumber and milling machinery busy at a growing number of wood products companies, including Montreal’s Nordic Structures, Sauter Timber in Rockwood, Tennessee, SmartLam, in Columbia Falls, Montana, and D.R. Johnson, in Portland, Oregon.
Oregon-based D.R. Johnson Wood Innovations, a subsidiary of D.R. Johnson, specializes in the manufacture of cross-laminated timber, or CLT, and glue-laminated beams from Douglas fir and Alaskan yellow cedar. D.R. Johnson Wood was the first U.S. company to receive APA/ANSI certification to manufacture structural CLT panels – and CEO Valerie Johnson plans to help grow the U.S. market.
D.R. Johnson has received the first U.S. certification to manufacture cross-laminated timbers (CLT) under a new standard approved last year by the American National Standards Institute. D.R. Johnson is one of only three North American companies certified by the Engineered Wood Association to construct CLT for use in buildings.
Johnson’s company employs 125 at a traditional sawmill and laminating plant, which was recently expanded by 13,000 square feet for increased CLT production. They’re currently fielding calls from hopeful builders, and manufacturing samples to be tested for fire safety and structural quality. One recent new wood construction project is a 14-story wooden apartment tower being built in Portland, Oregon.
From Woodworking Network: https://www.woodworkingnetwork.com/wood/pricing-supply/timber-construction-has-lumber-milling-machinery-rolling
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 | 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 | Oct 7, 2016 | News
If the vast potential of timber construction isn’t obvious, a new exhibit at Washington D.C.’s National Building Museum aims to clear things up. Running through May 2017, the USDA-sponsored Timber City is drawing attention to the recent boom in a worldwide movement toward timber construction.
It’s opening up a new market that has been turning the mills at a growing number of wood products companies, including Montreal’s Nordic Structures, Sauter Timber in Rockwood, Tennessee, and D.R. Johnson.
Oregon-based D.R. Johnson Wood Innovations, a subsidiary of D.R. Johnson, specializes in the manufacture of cross-laminated timber (CLT) and glue-laminated beams from Douglas fir and Alaskan yellow cedar. They’re the first U.S. company to receive APA/ANSI certification to manufacture structural CLT panels – and they hope to help grow the U.S. market.
D.R. Johnson is one of only three North American companies certified by the Engineered Wood Association to construct CLT for use in buildings. The company employs 125 at a traditional sawmill and laminating plant, which was recently expanded by 13,000 square feet for increased CLT production. They’re currently fielding calls from hopeful builders, and manufacturing samples to be tested for fire safety and structural quality.
D.R. Johnson says the system for constructing CLT involves assembling prefabricated parts, speeding construction, and paring labor costs. The company partnered with wood processor manufacturer USNR to build a custom panel press for CLT.
From Woodworking Network: https://www.woodworkingnetwork.com/events-contests/event-coverage/timber-construction-exhibition-shines-light-industry
