The Bow

The Bow is the first phase of the regeneration of two city blocks on the east side of Centre Street, a major axis through downtown Calgary. Providing a headquarters for a major energy company and attuned to the local climate conditions, its form was shaped by both environmental and organizational analysis.

At the time of construction, The Bow was the city’s tallest building and Canada’s tallest tower outside of Toronto. A bold landmark on the skyline, the project is equally significant in urban, social and environmental terms: the public base is filled with shops, restaurants and cafés and extends into a generous landscaped plaza, while the office floors are punctuated by three six-storey sky gardens to encourage natural ventilation and help to significantly reduce energy use. Connecting to the city’s +15 Skyway network, the scheme completes a vital link in the downtown pedestrian system offering a retreat from the city’s harsh winters.

The building’s form was shaped by analysis of the climate. The tower faces south, curving towards the sun to take advantage of daylight and heat, while maximizing the perimeter for cellular offices with views of the Rocky Mountains.

By turning the convex façade into the prevailing wind, the structural loading is minimized thus reducing the amount of steel required for the inherently efficient diagrid system. Each triangulated section of the structure spans six storeys, providing superior structural efficiency, while helping to visually break down the scale of the building. At the time of completion, it was the first time a triangular diagrid has been applied to a curved skyscraper in North America.

Where the building curves inwards, the glazed façade 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. This atrium collects solar radiation in a predominantly ‘heating climate,’ greatly reducing the building’s energy consumption. At the same time the large curving floorplates offer a window office to in excess of 70% of staff. This, combined with floor-to-ceiling glazing, reduces the need for artificial lighting. Heat produced within the offices is also recycled through the atria to further reduce energy consumption. Offices have the benefit of displacement ventilation via the raised floor which is shown to be far more efficient than many other means.

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Project Details