Waterfall Building

One of Arthur Erickson’s last built projects, the Waterfall Building was designed as a “live-work” infill development, with four- to six-storey commercial spaces and residential buildings linked around a central courtyard.

Accessed from the street by passing under a 20m concrete bridge that spans the east and west buildings, the project gets its name from the dramatic curtain of water that falls from the underbelly of its entrance bridge.

Fast + Epp’s primary structural challenge was to design this iconic gateway – a bridge that would look light, yet still carry the significant weight of three storeys of concrete construction. Complicating matters, the architect wanted glazed façades to be free of shear walls or lines of diagonal bracing.

In response, we formed the bridge deck using a site-cast cellular post-tensioned concrete deck with a circular soffit profile, 1.8m deep along its centre line but tapering to only 400mm deep at the edges. As a result, transverse 15m-long shear walls balance over the stiff centre ribs of the deck, and longitudinal concrete corridor walls are engaged compositely with the deck, thereby tying the slabs together as a frame to share the forces.