A spectacular make-over by renowned architect Frank Gehry has increased the capacity of the Art Gallery of Ontario (AGO) by 47% by linking existing historic buildings with daring new architectural features.
As structural engineer for the project, Halcrow Yolles has successfully risen to the challenge of realising the curvaceous and often gravity-defying elements of the design while preserving the building’s historical assets.
Gehry, who is famous for Bilbao’s futuristic Guggenheim museum, was given the task of tying together 108 years of accumulated buildings that house Canada’s largest collection of art. Halcrow Yolles’s engineers had to contend with merging the historical structures with the new features, relying at times on foundations that date back to the invention of the internal combustion engine.
One of the most remarkable features of the new AGO is that one entire facade is coated in glass, making it appear suspended in mid air. Other challenges for the structural engineers include cantilever and spiral staircases, tilted skylights and the addition of ten extra floors.
The skylights are cunningly tilted so that visitors experience plenty of natural light, but without the danger of ultraviolet light damaging the art. Meanwhile the design of the main spiral staircase, which rises through 27m, had to accommodate mechanical zones for heating, cooling and lighting within an ever changing curvature and a varying height balustrade. The complex geometry was overcome by creating a standardised system of steel members to simplify construction, and reduce cost and time.
A new glass and curved glulam façade spans 180m along Dundas Street, rising 21m above the street level. The challenges for the design team included how to effectively deal with both wind and load forces while minimising the size of nearly 1,900 structural members. During the design Halcrow Yolles analysed 200 load case scenarios to ensure the structure’s grid could withstand the load.
The Barnacle stair “clings” – as its name suggests - to the exterior of the building and cantilevers 11m from the South Tower directly above The Grange House, the fourth oldest surviving building in Toronto. Vibration has been minimised by installing a tuned mass damper system that stabilises the staircase while it is in use and during inclement weather conditions.
The design of the South Tower called for a ten-story addition over the oldest part of the AGO building. Challenges faced by the design team included how to incorporate the structural columns necessary to support the additional loads within the antiquated structural system of the original building, which was designed in 1911.
The AGO has existed for over 100 years and houses over 68,000 works, spanning from 100 AD to the present, nearly half of which document the contributions of Canadian artists such as Emily Carr, the Group of Seven and Tom Thomson. It also features one of the world’s largest collections of Canadian Inuit art.
Over the years the museum has expanded in an ad hoc fashion, and “Transformation AGO” was conceived as a major renovation that would bring unity to the facilities. Gehry, who grew up near the museum, was enlisted to design the scheme – his first art museum in North America and his first commission in his home country.
Construction began in 2005 and finished in 2008 at a total cost of £157 million. The project has added 9,000 sq m of new space, creating a 20% increase in overall building size and a 47% increase in art-viewing space. A further 18,000 sq m of space has been renovated.