Sea Change

Vancouver’s Aquarium is as venerable as an institution gets in Canada’s West Coast metropolis. Despite this, the calibre of its architecture has until recently failed to live up to its reputation in the community. Prior to the insertion of the Pacific Canada Pavilion in the existing courtyard, the Aquarium entry sequence was vague and unsatisfying. It led to a rabbit warren of displays without any focus or orientation space. The key success of Bing Thom Architects’ new room is to provide a dynamic central volume for the collection of existing buildings. The shape of the space was dictated by the outline of the existing courtyard, which created an obvious challenge: the space is somewhat awkward, requiring a number of access points. This reduced the ability of the wall surfaces to control the architectural dynamic of the space.

As a result, the ceiling had to be enlisted to play the central unifying role. Accordingly, the most striking feature of the new space is the system of composite wood and stainless steel trusses. The stacked triangular organization of these trusses frames a new diffused skylight. Unusual for a span of this length, the trusses are very close to the floor, which permits a close-up visual inspection of the detailing. Fortunately, careful scrutiny of the detailing of these trusses does not disappoint. Although the combination of steel bottom chord in tension and wood top chord in compression has become something of a West Coast clich, here it is rendered with poetic expression and airtight structural detailing. In particular the increased number of the lower chords in the trusses is a precise articulation of the higher loads on the bottom chord relative to the higher one. Unfortunately, this clean resolution is not consistently carried through to the supporting columns. Only one column is exposed, located at the new exterior faade. In other places, the trusses disappear into the walls, a detail that contributes to a sense of unresolved loading. Also curious is the choice to paint over the wood portion of the trusses and the adjoining surfaces in a single colour of neutral brown. While this uniform colour replicates the tones of the West Coast forest–one of the design intentions–the repercussion is that it reduces the visual sense of the structural hierarchy.

The lighting strategy is also a key participant in evoking the qualities of the coastal forest, with its characteristic low light level and patches of sunlight poking through the trees. The triangle of skylight framed by the composite trusses incorporates a unique parabolic filter to direct sunlight into the centre of the display pool, which replicates the local sea conditions. This filter has a diffusion ratio of 1 to 1,020, minimizing glare and keeping reflections off the display glass. The dark sea of the north Pacific, distinct from the brightness of the tropics but every bit as full of life, is allowed its subtle expression.

Another lighting challenge was created by the desire to open towards the former killer whale display. Transparency would be, inevitably, accompanied by an overabundance of light. To handle this problem, the exterior glazing combines two layers of glass with a dot pattern frit on the inner face of the exterior panel. This reduces the light transmission by 80%, allowing a view to the exterior pool while minimizing light penetration into the central Pavilion.

The pleasure in structural detailing exhibited throughout the Pavilion is also picked up in the vertical mullions of this glazing. Another composite structure of vertically oriented pre-curved parallel strand lumber (PSL) and stainless steel elements acts as wind bracing for the glass wall. The short span could probably be handled by more conventional means such as aluminum mullions, but the more dynamic solution chosen here evokes the expressive nature of whalebones and ship construction and provides a delightful tactile surface. According to the architects, the use of PSL in this application is unique.

A couple of other details are worthy of note. The delicacy of the glazed handrails does not interrupt the continuity of the volume, and allows inviting views to the lower exhibit area. The polished concrete floor employs a random scattering of brass and stainless steel shavings–a reward for observant visitors.

It is no coincidence that this precise orchestration of tectonic expression and sense of locale coincided with the Aquarium’s abandonment of the circus-like killer whale shows. The substitution of a sense of place for surface spectacle offers an analogous lesson for architects.

Bruce Haden is a principal of Hotson Bakker Architects and a regional correspondent for Canadian Architect.

Client: Vancouver Aquarium Marine Science Centre

Architect team: Bing Thom (lead designer), Michael Heeney (project director)

Structural: Fast & Epp Partners

Mechanical: Keen Engineering

Electrical: Schenke/Bawol Engineering

Contractor: Shimizu Canada Engineering

Optical Physicist: Department of Physics, UBC

Acoustics: Brown Strachan Associates

Area: 13,000 square feet

Budget: $3 million

Completion: 1999

Photography: Martin Tessler