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 | 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 | 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 5, 2016 | News
Say what you will about wooden construction, it is sustainable. So it’s great that even large structures are now being built out of wood. One awesome example of this type of architecture is Brock Commons, a University of British Columbia student housing tower. It will rise to an impressive 174 ft (53 m) and will be the tallest wooden residential tower in the world once it is complete. Which it very nearly is.
It took just 66 days to build the wooden tower. It’s not quite finished yet though, but once complete it will contain 33 four-bed rooms, and 272 studios, so the 18-floor tower will be able to accommodate 404 residents. The tower was designed by Acton Ostry Architects.
The structure consists of 16 floors of five-ply cross laminated timber (CLT) floor panels, and has a steel-framed roof, as well as a few concrete sections, namely the base and stairwells. The façade of the tower is made of prefabricated panels that had the windows pre-installed. These panels contain 70 percent wood-based fibers with steel stud framed sections, and form a high-pressure laminate cladding.
The construction went remarkably quickly. At first they managed to build one floor per week, but were able to go faster after that, building two or more floors per week. Not including the concrete sections, they’ve been able to complete the entire structure in just over three months, which given the size of the tower is quite remarkable.
The Brock Commons residence was also designed according to LEED Gold certification standards, and will receive this certification once it is completed. They estimate that it will be completed in May, 2017, which is four months ahead of schedule. They are currently installing the steel roof, which they hope to complete in a couple of weeks.
From Jetson Green: https://www.jetsongreen.com/2016/09/tallest-wooden-tower-in-the-world-is-almost-complete.html
by Web Editor | Aug 31, 2016 | News
In Vancouver, Canada, the towering timber Brock Commons just had its final panel installed, making the dream of the world’s tallest timber building a reality, reports the website Inhabitat.
In just 66 days – ahead of the original scheduled timeframe – the exterior of the Acton Ostry Architects‘ record-breaking design has come to fruition, which could bump up the projected fall 2017 completion date to next year’s spring semester. The final panel of the University of British Columbia student housing structure was lifted and installed earlier this month.
John Metras, managing director of UBC Infrastructure, said, “Construction just went really smoothly. It was well designed and the construction sequence went smoothly.”
Construction began last November, followed by the erection of the building’s freestanding concrete cores earlier this year.
To ease fire safety fears of an 18-story timber structure, Brock Commons is outfitted with a sprinkler system and the wood is encapsulated in drywall and concrete. The lighter weight of the building also allows for better energy dissipation during an earthquake, making it proficient at withstanding all kinds of disasters. Students will be able to move in next year, quite possibly in the spring semester.
From ProudGreenBuilding: https://www.proudgreenbuilding.com/news/worlds-tallest-timber-building-topped-off-ahead-of-schedule/
