The completion of a 5-story mass timber commercial office building named Terminus in the city of Langford, British Columbia, on Canada’s west coast, marks an exciting first in the world of seismic systems for timber structures. The building includes 4 stories of post-and-beam mass timber with Douglas Fir glulam beams and columns and Spruce-Pine-Fir (SPF) cross-laminated timber (CLT), all supplied by Structurlam. While the structure and its detailing are clean, elegant, and modern, what is truly unique about Terminus is its steel-timber hybrid seismic force resisting system (SFRS).

Tallwood 1 at District 56 is a twelve-story mixed-use mass timber building located in Langford, British Columbia, Canada, designed by Design Build Services (DBS), Jack James Architecture, and Aspect Structural Engineers (Figure 1). Tall wood construction is a relatively new typology across North America, and this building is the first structure to be constructed under the British Columbia Building Code’s (BCBC) new Encapsulated Mass Timber Construction (EMTC) provisions, a typology that drastically reduces a building’s structural embodied carbon. EMTC is very similar in limitations and fire requirements to the 2021 IBC Type IV-B construction type. As appropriate to a novel system, the design and construction of this building presented some significant challenges and valuable lessons along the way, with one of the primary challenges being the building’s location: Langford is located in the Cascadia Subduction Zone, a region that is among the highest in seismic demand in all of Canada. Tallwood 1 was the tallest steel-timber hybrid structure in Canada when it was completed in 2021.