When Apple’s flagship store on Chicago’s Michigan Avenue required steel connections for a glass pavilion with a seemingly floating roof, the architectural vision presented substantial engineering constraints. The roof’s distinctive profile relied on cantilevered fins extending around the entire perimeter, creating complex connection points where multiple structural members intersected at tight angles.
The building’s framework consists of four box columns supporting a rectangular frame of box girders, with cantilevered fins defining the roof’s profile. Each intersection required custom connection solutions from CSD’s team.
At locations where structural members met, CSD’s engineers addressed load transfer challenges while maintaining the required external profile. Some connections used box sections cut apart and reinforced with internal stiffeners. Other joints required solid plate nodes to accommodate welding from multiple directions.
Box section splices within the roof’s profile required complete concealment while maintaining structural continuity. CSD developed specifications for shims, bolt patterns, and bolt tightening requirements contained within the architectural envelope.
The cantilevered fin connections required low-profile details that provided stability to the extended framing. CSD’s team used combinations of end plates, stiffened extended plates, and flange plates specific to each location.
The completed connections enabled Apple’s architectural intent while meeting structural requirements for the Michigan Avenue store.
Photos by Brian Fritz Photography