7 South Dearborn
With 108 stories and an antenna together reaching over 2,000 feet, 7 South Dearborn was conceived to be a figural piece that would stand alone in the city of Chicago as the tallest structure in the United States and the symbolic center point of the downtown central business district.
The tower represents a major advance in the engineering of tall buildings. The record-setting height is made possible by the building’s stayed mast structural system, formed by a series of spaces that evolve from a reinforced concrete core. A number of widely spaced columns dot the perimeter of the office component, allowing the interior to be column-free.
The cantilevering of the upper 57 floors from a concrete core provides 11-foot floor-to-ceiling uninterrupted views in all directions. The spandrel panels on the south, east and west surfaces were designed to be clad with integrated photovoltaic panels. The “notches” separating the upper sections of the residential floors act as ventilators to reduce the vortex-shedding forces on the overall mass.
The mixed-use complex includes 360 residential units on 40 floors, office space on 36 floors and 800 parking spaces on 12 floors in addition to 13 floors of communication facilities.