2006: Apple Store, New York City – Structural Glass
Innovation: Structural Glass
Location: Apple Store, Fifth Avenue, New York City
Architects: Bohlin Cywinski Jackson
Structural Glass Engineering: Eckersly O’Callahan
The iconic 90 paneled 32 foot structural glass cube of the Fifth Avenue Apple Store was created to enhance Apple’s retail brand and has since been patented by Steve Jobs. The cube is an entrance to the retail space below which visitors descend to on a circular all-glass stair or elevator. The store uses the strongest grade structural glass in the world that at the time could only be produced by Seele GmbH & Co. in Germany. During the design process, finite element analysis software was used to test the stresses and deformations present in the structure resulting from the vertical and horizontal loads. With the analysis focusing on its weakest points at the edges and corners, which are somewhat relived by the use of vertical fins. 
Structural glass is the result of laminating technologies that introduce flexibility and strength to the material along with shatter and UV resistance. Laminated glass has in internal thermoplastic material layers that hold the two surrounding layers together during high impacts. This is the same technique used in car windshields. The outer layers consist of annealed glass which strengthens the materials by allowing some internal stresses to be relieved .
The New York store was the first to include a cylindrical stair encompassing an elevator. The design had to consider seismic loads, foot-traffic, sound vibrations and fire-coatings. Here they used the titanium double grip system from the original San Francisco stair case, but this time they had to account for the 60 degree sloping stair on curved panels as opposed to horizontal treads .
As a result of this technology, structural beams, columns and other members can be made out of glass.`