It’s not every day that you build a tunnel around an underground LRT that curves up a slope to the surface – and then use that tunnel as the foundation for a landmark library!
East Village Master Developer Calgary Municipal Land Corporation couldn’t have picked a better team of structural engineers for the job. Entuitive, a Calgary-based firm, already had experience in a job that had many parallels to the NCL encapsulation – a New York City project called Manhattan West in which 13 commuter train tracks, which carry more than a million travelers a day, were covered to create a foundation for four enormous towers.
“We applied a lot of the lessons we learned in New York to the NCL project,” says Brock Schroeder, managing director of Entuitive.
The NCL project was smaller, but still on an impressive scale – see the facts and figures that accompany this article. “There were challenges,” Schroeder says. “But we wanted to combine the LRT encapsulation with the foundation in order save money. That way, the library has more money to enhance library services.”
The encapsulation project was underway before the NCL building design was complete, so the tunnel helped inform the design. For instance, the LRT track had a quirky geometry – it didn’t rise in a continuous grade – which meant that the shape of the building had to be tweaked to fit. The contact wire above the train, which provides power, had to be lowered so that the tunnel didn’t project into the library too far: it was decided that the wires would go into support beams.
You can watch the encapsulation process on an animation at calgarymlc.ca/ncl. You’ll see the piles go in, the two walls go up, and the precast roof go on – which happened in a record two evenings so as not to disrupt service.
“There are fewer and fewer open spaces for building in cities,” says Schroeder. “You’ll see more creative solutions like this one in many cities in the future.”