BIG's iconic Vancouver skyscraper twists and turns around the regulations

However, an opportunity was found in constraint as the 30-meter setback from the bridge only applies until the tower reaches 30 meters in height. The provision therefore allowed for the concept of a triangular footprint that expands as it rises. At its highest level, the floorplate steps out approximately 80 feet. The form becomes rectangular, reclaiming valuable area while providing an icon for the city’s skyline and generous ground-level public space.

This stepping out and the asymmetrical twisting posed a challenge to project engineering firms Glotman Sipson and Buro Happold. Their task was made even more challenging as the site lies in a seismic region. To provide the required stability and flexibility, the engineers strung cables through the walls to offer post-tensioning. The post-tensioned steel cables, also called tendons, are tied to thick concrete walls to provide the structure’s core stability. Furthermore, larger-than-average expansion joints and gaskets between panels give the required flexibility and mobility.

On the exterior, the seemingly asymmetrical openings per floor eventually formulate a single face that resembles a built wall. Covered by glass surfaces, the facade contributes to the original concept of visually linking Granville Street to the city as a 'control tower' while maintaining a LEED Platinum rating. 

 

Interestingly, BIG and Vancouver House developer Westbank also teamed up on a similar project called Telus Sky Tower in Calgary, which appears as a kind of inverted version of Vancouver House as a skyscraper with a dramatic sloping exterior that narrows towards the top floor. The architect developer team is currently also collaborating on future high-rise projects, including one in Vancouver and one in Toronto.