The Ledge at Skydeck Chicago
(Winner - Spark!)
Designer: Ross Wimer - Design Director
Design Type: Experiential
Launch Year: 2009
The Ledge at Willis Tower, formerly Sears Tower, was created to enhance a classic building with an innovative addition that is in the spirit of the original design. Where renovations done to modern structures are often created to call attention to themselves by dissonance, this project does so by absence. Their minimalism allows these five-sided glass balconies to provide views in all directions and an experience that approximates being suspended in the air. There is a great deal of unique technology that was employed to allow for this minimal result. The ledges are approximately 4 feet deep, 10 feet high, and 10 feet wide. Each ledge is made of 1.5 inch laminated glass panels hung from a steel frame that rides on rails, allowing it to be retracted into the building for cleaning and maintenance. The design process included research of glass, to find laminations that would provide proper strength and durability. These assemblies were tested to failure to determine the ultimate capacity of the floor (which is approximately the weight of an elephant). To provide the clearest view possible, a specially produced glass was used. It has less iron in its content and consequently has virtually no green tint. A unique coating primarily used for museum cases has been applied to the glass to eliminate reflections. A steel frame system was developed not only to support the glass, but also to allow the ledges to be slid like drawers into the building for maintenance. Additionally, the hollow tubes of the frame act as a duct to supply conditioned air to the ledges and maintain air-flow across the glass to eliminate condensation of moisture.