Architect: Gehry International

Client: Art Gallery of Ontario

Completion: 2008
Category: Cultural

Project Type: Structural Engineering, Feature Structures

Attribution: Crispin Howes*

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Awards
2009–Ontario WoodWORKS!
Institutional Wood Design Award

2009–CISC Ontario Steel Design
Award of Merit

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The Art Gallery of Ontario (AGO) is a world-class cultural institution contributes to the fabric of Toronto. Transformation AGO is a major development which integrates six previous additions and renovations over the last century. The re-developed building is accented by a series of feature elements which include a glass and timber facade along Dundas St. to the north, a wood-clad sculptural staircase with Walker Court, and stainless steel clad exterior staircase above Grange Park to the south.

 

The Dundas St. facade extends the full 600ft of the building and rises 70ft above street Level. The architecturally exposed structure mixes Douglas Fir Glulam framing with strategic instances of structural steel and is clad with curved glass panels. The structural solution employees a highly optimized multi-layer system that minimizes the sizes of the framing members while maximizing the overall transparency. The facade has four distinct areas. The central zone with a gently varying curvature encloses the 400ft long sculpture, Galleria Italia. Abutting each end of the Galleria are two exterior zones with an aggressively warped curvature, which are referred to as “wings.” Finally, a “skirt” extends the full length of the building. The “skirt” conceals a stainless steel-lined gutter and transitions the experience of the façade from a building scale to a pedestrian scale.

 

The heart of the renovated building is Walker Court where the feature staircase cantilevers overhead, curves upwards thru the glass roof and provides an exterior enclosed pathway that undulates up the north face of the South Tower. The structural solution concealed beneath the Douglas Fir cladding utilizes a pair of steel plate girders within the stair’s balustrade. The plate girders are curved not only in plan but also in elevation to match the varying height of the balustrade. A series of brake-formed steel plates link the plate girders to support the treads and risers of the stair. An integrated plenum is incorporated below the treads and risers in the enclosed exterior of zone of the stair. The plenum feeds ductwork incorporated inside the balustrade assembly to provide condition air along on the face of the exterior curved glazing. The form of the stair offers visitors to the AGO multiple experience. Viewed from below, the stair is experienced as a sculptural element. Ascending and descending stairs, views to the surrounding gallery are revealed thru playful variations in the path of the stair and the height of the stair’s balustrades.

 

Overlooking Grange park is a second feature stair, informally called the “Barnacle Stair” for the appearance of clinging to the face of the face of the titanium-clad South Tower. The stair cantilever outward by 30ft and links the two Modern Art gallery floors of the South Tower. The staircase is clad in curved stainless steel and glass. The structural solution builds on the structural system from the Walker Court staircase, by adding posts above the curved steel plate girders within the balustrades to support a roof above. A custom tuned mass damper (TMD) is concealed below the mid-landing at the furthest point of the cantilever. This TMD helps control the vibration response of stairs as visitors ascend and descent.

 

Transformation AGO was realized with a BIM approach and, at the time, was a pioneering application of the technology within the Canadian construction industry. Design and coordination of the feature elements made extensive use of CATIA. BIM models were issued as control geometry for construction. The models were further developed and detailed by the construction trades and were the basis for CNC fabrication of components. 3D scanning and surveying was used on site to coordinate, erect, and document the construction. The design and construction approach for the Dundas St. façade was the subject of a case study by WoodWorks, an industry organization focused on advancing timber construction within Canada.

 

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