Special events have been held in Calgary this week to mark the official opening of The Bow, a 237-metre-high headquarters tower – the city’s tallest building and Canada’s tallest tower outside Toronto. A bold new landmark on the skyline, the project is equally significant in urban, social and environmental terms: the public base of the tower is filled with shops, restaurants and cafes and extends into a generous landscaped plaza, while the office floors are punctuated by three six-storey sky gardens, which encourage natural ventilation and help to significantly reduce energy use.
The building’s form was shaped by analysis of the climate and organisations. The tower faces south, curving towards the sun to take advantage of daylight and heat, while maximising the perimeter for cellular offices with views of the Rocky Mountains. By turning the convex facade into the prevailing wind, the structural loading is minimised, thus reducing the amount of steel required for the inherently efficient diagrid system. Each triangulated section of the structure spans six storeys, helping to visually break down the scale of the building.
Where the building curves inwards, the glazed facade is pulled forward to create a series of atria that run the full height of the tower. These spaces act as climatic buffer zones, insulating the building and helping to significantly reduce energy consumption. In order to promote collaboration across the companies and bring a social dimension to the office spaces, vertical access to the office floors is directed through three spectacular sky gardens, which project into the atria and incorporate mature trees, seating, meeting rooms, catering facilities and local lift cores. Staff facilities in these atria are complemented by an auditorium at the very top of the building.
The Bow also establishes lateral connections with surrounding buildings. The tower is fused at two points to Calgary’s system of enclosed walkways. The second floor is open to the public and integrates shops and cafes, and with the only public connection over Centre Street, the scheme completes a vital pedestrian link in the downtown network. Externally, the building’s arc defines a large landscaped public plaza, at the heart of which is a landmark sculpture by Spanish artist, Jaume Plensa.
CREDITS.
Architects.- Foster + Partners. Collaborating Architect.- Zeidler Partnership
Structural Engineer.- Halcrow Yolles
Quantity Surveyor.- Altus Helier (Partial)
M+E Engineer.- Cosentini
Landscape Architect.- Gustafson Guthrie Nichol (Carson McCulloch - Local)
Lighting Engineer.- Claude Engle Lighting Design
Additional Consultants.- Sturgess Architecture, DA Watt, KJA, Kellam Berg, Cerami, Gensler, Cygnus, leber Rubes, Transolar, RWDI, Brook Van Dalen, Leber Rubes, Hayes Davidson.
Appointment.- 2005
Construction start.- 2007
Completion.- 2013
Area.- 199 781 m²
Height.- 239 m
Client.- Matthews Southwest Developments Limited
