Canadian telecommunications firm Telus has unveiled the design of its new downtown Calgary, Alberta, home: a 750,000 sq ft tower that will transition from a sleek office block at its lower levels to a textured residential tower at its upper levels. Bjarke Ingels Group
A 700 ft tall tower in Calgary, Alberta, that will open by 2017—or earlier—will seamlessly go from being a sleek office block to a whimsical residential tower as it rises.
August 6, 2013—TELUS, a telecommunications company based in Calgary, Alberta, has unveiled the design of its new downtown home: a glossy, 700 ft tall tower that will curve to combine a sleek office block in its lower levels with a textured residential tower in its upper levels. The 58-story tower will also boast retail space, a sky garden with a dedicated elevator, and publicly accessible spaces.
Designed by the architecture firm Bjarke Ingels Group, which is based in Copenhagen (København), Denmark, and New York City, the 750,000 sq ft mixed-use tower is intended to be an organic, “soft” addition to the Calgary skyline, according to Bjarke Ingels, who spoke last month at the design’s unveiling.
“The challenge was to make a mixed-used building with a single identity for the main office tenant, TELUS,” said Thomas Christoffersen, who wrote in response to written questions submitted by Civil Engineering online and is one of the partners in charge of the project for the Bjarke Ingels Group. “They were not looking for an office building with a residential building [thrown] on top, and we didn’t want the residential component to look like offices. So we had to find a solution that accommodates both.”
In addition to office and residential spaces, the 700 ft tall tower will
boast retail and public spaces as well as a sky garden with a
dedicated elevator. The tower is being designed to a platinum level
in the U.S. Green Building Council’s Leadership in Energy
& Environmental Design system. Bjarke Ingels Group
The solution that the design team created gives a distinct, clean, and traditional curtain-wall facade to the office floors, but this facade gives way to a “skin” for the residential section that presents the balconies as extruded elements, thereby forming the tower’s striking, seemingly pixilated silhouette. Two entrances, one for offices and the other for residences, will provide access to dedicated elevator cores.
Traditional concrete construction with elevator cores, flat-slab floor plates, shear walls, and columns will be used for the tower. “Design of multipurpose towers with different functions on top of each other often results in different structural systems and geometries with costly transfer structures at the points where the use of the building changes,” Christoffersen said. Careful design work, however, ensured that this would not be the case with this tower, he noted.
The column spacing in the east–west direction of the building remains the same throughout the tower, according to Christoffersen, whereas in the north–south direction the columns are placed toward the center as the thick office floor plates shrink to become the residential tower plates.
The structural engineering of the tower was performed by Glotman-Simpson Consulting Engineers, of Vancouver, British Columbia. “The exterior columns continue to ‘walk’ as the building facade steps in,” said Anthony El-Araj, P.Eng., P.E., LEED AP, a principal at
Glotman-Simpson and the project manager for the structural engineering firm’s work on the project. El-Araj wrote in response to written questions posed by Civil Engineering online. “One row of columns is introduced at [each of] the east and west bays, [and the loads are] are transferred at the transition level between office and residential,” he noted. “These columns allow for the residential floor slabs to be thinner than [in] the office and are arranged to work within the residential units.” Beginning at the 12th floor, the width of the floor plates shrinks by about 60 percent, going from approximately 108 ft at the podium level to roughly 42 ft at the roof level.
Traditional concrete construction with elevator cores, flat-slab floor
plates, shear walls, and columns will be used for the tower, albeit
with design tweaks that enable the width of the floor plates to
shrink by about 60 percent as the tower rises. Bjarke Ingels Group
“This gradual transition eliminates any need for additional transfer structures where the use of the tower changes, making it an economic and sustainable solution of a mixed-used tower,” Christoffersen explained.
“The walls that frame the residential elevators continue through the entire height of the building and form part of the shear wall system,” El-Araj said. However, while the shear walls that frame the office elevator core terminate at the top of the office floors, he noted, shear walls that rest upon columns located along the unit partition walls in the residential floors will supplement the lateral support provided by the residence’s elevator core.
The foundation will take the form of conventional pad and strip footings with larger mat footings supporting the core shear walls, according to El-Araj. However, “the footprint of the podium and below-grade parking structure is small relative to the tower, which restricts the parking,” he noted. “So, four of the shear walls below grade at the parking [level] are transferred to allow additional parking stalls.”
The $400-million development is being designed to attain platinum certification in the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) ranking system, according to Darren Entwistle, the president and chief executive officer of TELUS, who spoke last month at the design’s unveiling. The tower is to be completed in 2017, and once in operation it will use 80 percent less energy than a conventional tower of similar size, Entwistle said.
In addition to the Bjarke Ingels Group and Glotman-Simpson, the Canadian architecture firm DIALOG, the real estate developer Westbank, of Vancouver, British Columbia, and the Toronto-based real estate investment trust Allied Properties are associated with the project.