Canada’s tallest wood building opens as showpiece in Prince George

The Wood Innovations and Design Centre (WIDC) officially opened in downtown Prince George, B.C. last week, becoming the tallest contemporary wood building in North America.

At six storeys plus the mechanical penthouse, the WIDC academic and institutional building stands 29.3 metres high. Europe has several contemporary wood buildings of similar scale, but the tallest worldwide is in Melbourne, Australia, at 32.2 metres high.

The WIDC is intended as a showpiece of wood construction and is built using various types of natural timber and engineered wood products. The University of Northern British Columbia will occupy the first three floors. This space, which includes lecture theatres and research laboratories, will mostly be occupied by faculty and graduate students enrolled in the new master’s programs in wood engineering and science that UNBC will be launching in September 2015.

The WIDC’s primary structure consists of heavy post and beam construction with built-up cross laminated timber (CLT) floor panels. The concept is a “dry construction” design, which virtually eliminates the use of concrete above the foundation, except for in the mechanical roof penthouse.

The glulam beams, for example, frame into glulam columns using proprietary dovetail aluminum dovetail Pitzl connectors, which allow the columns to run continuously from the foundation to the roof.

The building’s lateral-load resistance is provided by the elevator and stair core walls, which consist of CLT panels connected vertically with self-tapping screws. Shear walls are anchored to the foundations using a combination of shear brackets connected to the panels with self-tapping screws and hold-down anchors.

Another innovation is the staggered floor slab design which allows the mechanical and electrical systems to run between the staggered timber slabs both below the floor and above the ceiling. An acoustic-insulated subfloor system is laid loosely over the chases with cut-out panels to provide access inside. The lighting and sprinkler systems are run in the ceiling recesses behind a simple removable wood slat finish. The wood structure is generally exposed.

Steve Craft, PhD, P.Eng. of CHM Fire Consultants of Ottawa says that the massive scale of the wood structure provides its fire resistance. “The entire structure is solid wood that’s very thick. The columns are in the order of 1 foot square; the beams are in the order of 1 foot wide x 1.5 feet deep. These are big cross-sections, so they have a large degree of inherent fire resistance.” In comparison, he explains, conventional light-frame wood construction relies on gypsum board for fire protection.

When exposed to the standard fire, massive timber elements char at a slow and predictable rate of around 0.6 mm per minute, Craft explains. The char layer insulates the relatively cool central portion of the wood member allowing it to carry the structural load. The mass timber structure easily provides the required one hour fire-resistance rating. The fire-stopping at the service penetrations and construction joints were fire tested in a Coquitlam, B.C. laboratory to the CAN/ULC-S115 test standard.

Besides accommodating the UNBC programs, the building will house staff from the B.C. Ministry of Forests, Lands and Natural Resource Operations. It will also be the location for the media and broadcast centre for the 2015 Canada Winter Games. This event takes place February 13 to March 1 in Prince George, involving 2,400 athletes and 4,500 volunteers.

The design-build team of PCL Westcoast Constructors was given the contract for WIDC by the B.C. government in 2013. Thirteen B.C. companies collaborated on the project. These included: Michael Green Architect, Equilibrium Consulting (structural), B.R. Thorson (code consultant), RDH (building envelope), MMM Group (mechanical, electrical, LEED), Aercoustics (acoustics), CHM Fire Consultants (fire safety), Opus Dayton Knight (civil), Geopacific Consultants (geotechnical), Inland Technical (commissioning) and Jay Lazarin (landscape).

To see a video about building the project, click here.

https://www.youtube.com/watch?v=be1LVts-yjU&feature=youtu.be