Click on image to view large versionBrentwood Skytrain Station
Burnaby, BC
Busby + Associates Architects (Vancouver, BC)
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This skytrain station occupies a flagship location on the new Millennium Line extension in Burnaby, a suburb of Vancouver. It is set nine metres above the median of Lougheed Highway, straddling a pedestrian bridge. The station is intended as a catalyst for development of the future Brentwood Town Centre.

The station encourages use of the transit system through attention to accessibility, safety, comfort, and appearance – priorities that were established during an extensive public consultation process. The design includes open spaces with clear visibility and generous canopies for protection from wind and rain. With the extensive use of glass, the station is transparent during the day and glows at night. The functional template for the station was based on train size and passenger volume. The design also incorporated standard infrastructure components such as lighting, signage, escalators, and elevators. A desire for civic presence led to the use of a heavy timber structure. As a North American precedent for this type of building, it required a demonstration of code equivalence to non-combustible alternatives.

The double-curved shell of each platform canopy is supported by a series of composite ribs set five metres apart. The tapering profile of the roof in both plan and section was achieved by cutting the ribs incrementally to nine different lengths. The upper (roof) portion is glue-laminated timber. Steel is used for the lower (wall) portion of the ribs, where wood could not function adequately. The two canopies are connected by a structural gutter, steel cross-bracing, and V-shaped steel struts that create a system of moment frames and transfer lateral loads across the central space. The exterior walls consist of overlapping glass panels that provide protection from the weather, natural ventilation and lighting, good visibility, and a safe environment for skytrain patrons.

Click on image to view large versionSteel is used in exposed locations and wood is used where it can be protected from hazards such as water, fire, and vandalism. For the structural ribs, glu-lam was chosen for its strength, predictable performance, and economical use of wood fibre. In contrast, the roof decking is low-tech: 38mm x 89mm softwood, reclaimed or locally sourced, laid side by side on edge - a system that is sufficiently flexible to follow the double curve. The platforms, mezzanine land-bridge, and supporting structure were all cast on site using 50 per cent fly ash concrete. Although the extended curing time required an additional set of forms to maintain the desired construction schedule, the environmental benefits justified the small cost premium.

Click on image to view large versionA 3-D computer model was used in design, shop drawings, and layout to compare alternatives and identify economic solutions. It showed that all of the ribs could have the same lower curvature and be made with the same jig. It also showed that a standard glazing system with swiveling clips and flat panels could be used for 70 per cent of the curved surface.

Transit infrastructure projects are central to the environmental agenda. They are intended to reduce carbon emissions from automobiles and to reduce urban sprawl by encouraging densification. This project complements these long-term environmental goals by using building materials and components with lower embodied energy.

 

 

Jury Comments:

This building dances between the lightness of movement and the solidity of a structurally anchored diaphragm. The curved sectional extrusion expresses a tectonic elegance in which steel and wood are exploited for their intrinsic strengths, while gravity, wind and seismic loadings are registered in the details. The project also portrays the teamwork that is required to marry architectural form, engineering and green building principles.

Daniel Pearl,
(Quebec)
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This project tempers a fundamentally technological vision of architecture with regional materials and a craft sensibility. The elegant sculptural form of the station is realized with careful detailing, thereby setting a high standard for Canadian public infrastructure projects.

Stephen Teeple, FRAIC
(Ontario)
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