Steel Shots: Floating with Steel

Suspending the 11 stories of new office space above two heritage structures as part of Toronto’s Queen Richmond Centre West building are three, 70-ft-tall architecturally exposed structural steel (AESS) delta frames connected by 35,000-lb cast steel nodes engineered, detailed and supplied by AISC Member Cast Connex. Photo: Courtesy of Cast Connex 

Toronto’s Queen Richmond Centre West office tower continues to rise and defy gravity; with steel.

The development includes both the modernization of an existing historic Toronto building and the construction of a new 11-story reinforced concrete office building perched atop three, 70-ft tall, architecturally exposed structural steel (AESS) "delta frames.”

AISC Member Cast Connex provided design-build services for the 35,000-lb cast steel nodes that form the central kernel points of the delta frames. The magnitude of the loading required that the 1-meter (39.375-in.) diameter tubular members of the frames, along with the cast steel nodes, be concrete filled for composite strength. The three delta frames are primary elements in the gravity and lateral force resisting systems for the building.

Each delta frame is an hourglass-shaped frame comprised of steel pipes - four rising from the foundation, meeting at approximately the mid-height of the frame, and continuing through to the tabletop to frame directly below the centerlines of the tower’s columns, which are placed on a 9-m by 11.25-m (29.5-ft by 37-ft) grid. This configuration halved the unbraced length of the inclined pipe columns, significantly reducing their required member size to provide a slim aesthetic. The result was a support concept that was far less obtrusive to the building’s soaring atrium and which would be a distinctive feature of the iconic development.

The project is expected to be complete by mid-2015 and receive LEED Gold Certification.

You can read more about the Queen Richmond Centre West project in MSC’s March 2014 issue.