A striking 90-metre-long steel-trussed bridge that also provides 40,000 square feet of program space at a suburban Toronto college campus is a real head-turner.
Since its creation, in 1968, the Ashtonbee Campus of Centennial College at Warden and Eglinton Avenues was not much to look at — if indeed you could see it at all.
Cobbled together on an L-shaped site fronting Warden Avenue with the flank running along Ashtonbee Road, an industrial side street, it was home to the institution's automotive and technical trades program. The main building on the site was previously a Volkswagen Canada assembly facility and garage. The other low-rise brick buildings were constructed and opened in 1973.
Flash forward and Centennial College partnered with the University of Toronto in expanding modern campus sites across Scarborough and East York — all except for Ashtonbee, which remained a series of low-profile, bunker-like structures.
Renewal was long overdue but the challenge faced by both the college and MacLennan Jaunkalns Miller Architects (MJMA) was how to not just add space but develop a master plan for the site which would allow for future growth and incorporate the existing structures.
In addition, they had to ensure they did not sacrifice the redeeming features of the campus, which were the series of landscaped courtyards only experienced and visible from within the property.
Architect Ted Watson, an MJMA partner, said while the campus did not have a lot going for it esthetically, "it did have good bones."
What it needed, the team and client agreed, was to refocus attention away from the Warden Avenue entrance and create a new face. The solution, said Watson, was to create a new entrance along Ashtonbee with the bridge structure serving as a massive archway. Vehicular traffic passes underneath it, as do pedestrians for whom the structure offers some protection from the elements.
The result is a triple-glazed curtain-walled bridge which not only serves as program space and a way to access one end of the campus from the but also lets in diffused natural light through the fritted glass. It also amplifies Centennial's branding because of its strong visual presence.
There is also a central atrium area with glass panels on the roof over the central stairway.
"A lot of students used the tunnel underground but no one really liked it, because it was dark and it felt unsafe," he said. "And it wasn't a comfortable gathering spot."
There was a need for a new library, recreational and administrative facilities that also created a problem, given the space limitations onsite and the college's requirement not to lose any parking.
The result is a functional and visually striking structure. The bridge comprises four parallel sets of six-metre deep steel trusses with wide flange chords and webs fabricated from architecturally exposed round hollow sections. The trusses at the north and south side of the building are visible through the curtainwall, and descend to the foundations to act as lateral bracing.
The roof is framed in metal deck on open web steel joists, while the upper floor uses precast hollow core concrete panels spanning to steel girders. Watson said the cast concrete flooring dampens vibrations from traffic which steel tends to amplify.
The industrial look is in keeping with the campus' technical curriculum and draws on its automotive history — and the regular "show and shine" car club meetings held there in the summer.
Site preparation and demolition was a bit of a challenge. First, the tight space made staging difficult, though Watson said the contractor EllisDon did secure some parkland temporarily. Second, the campus was operational so students and staff were coming and going and there was some Type 3 asbestos, which needed to be removed.