Circa 1877 is a new 20-story condominium building built on the site of one of Canada’s first craft breweries. The structure features six parking levels, 14 residential floors, and one mechanical penthouse level. The designers used precast concrete to accomplish many goals on this project.
“Precast concrete was selected for its consistent quality and speed of erection,” says Frans VandenHeuvel, project manager for Stubbe’s Precast. “Site access was also limited due to tight boundaries, so prefabrication made the most sense, allowing for minimal trades on site.”
Because the existing structure was one of the oldest manufacturing buildings to remain in use, it had been granted heritage status. Careful consideration was required when designing the structural layout to ensure that loads could be effectively transferred around the existing building. Design priorities included careful preservation and protection of the original brick facade during the erection of the precast concrete members, and the construction of foundations immediately adjacent to the structure.
“The aesthetic and structural possibilities of precast concrete allowed for the integration of the new and old to produce a stunning structure,” VandenHeuvel says.
To highlight the preserved facade, precast concrete construction was not allowed to substantially alter interior or exterior views. However, the older structure mainly relies on the new precast concrete structure for all of its lateral bracing. The final design also features a five-story, freestanding precast concrete column designed to support the tower above the heritage building. This was erected in various pieces with hidden vertical connections to provide a seamless look.
“One of the biggest challenges was the detailing and production of the parking garage elements,” VandenHeuvel notes. The heaviest components on the project were multiple precast concrete beams at the fifth-floor ceiling of the parking garage. Each had to be lifted into place using a separate mobile crane because the weight exceeded the tower crane’s lifting capacity.
Because the ramp is continuously sloping, the bearing ledges on the beams and walls had to be modeled with extreme accuracy. Even a small deviation from the shop drawings would have caused fit issues and misaligned sloping on site. A pool was integrated above the parking structure at the terrace level, adding further complexity to the design.
The team used three-dimensional modeling software to achieve a precise fit. “The use of advanced building information modeling software was a key in the success of this project, along with a great team,” says VandenHeuvel .
With installation taking about six days per floor, the contractor was able to progress quickly from the foundations to the roof slab with a small crew and a tower crane, delivering the finished project on time and within the budget.
“This was a milestone project for Stubbe’s,” VandenHeuvel says. “Providing an elegant tower extending up from a complex parking garage and heritage building proved to be a true test of our design and coordination capabilities, which we were pleased to execute while maintaining our high standards.”