John Hancock Center / Skidmore, Owings & Merrill

© Dave Burk, Courtesy of SOM 

Over fifty years after completion, the John Hancock Center, designed by American architecture firm Skidmore Owings & Merrill, has established itself as one of the world’s most recognized skyscrapers and an iconic example of late 20th century Chicago design, construction, and engineering. The building’s structural, programmatic, and architectural innovations combine to create a design that has become a city symbol.

John Hancock Center Technical Information

• Architects¹: Skidmore Owings & Merrill
• Location: 875 North Michigan Avenue, Chicago, Illinois, USA
• Owner/Developer: Jerry Wolman Associates
• Topics: Mixed Use, Skyscrapers, Steel Structure
• Site Area: 104,000 ft²
• Project Area: 2,800,000 ft²
• Height: 344 m (1,128 ft), Height to tip: 457 m (1,499 ft)
• Stories: 100
• Project Year: 1970
• Photographs: © Dave Burk, Flickr Users: © Kim Eriksson, © Ben Schumin, © Scutter Hohn

The John Hancock Center is gutsy, masculine, and industrial; reflecting the tradition of Chicago, where structure is of the essence.

– Bruce Graham, Skidmore, Owings and Merrill

John Hancock Center Photographs

© Dave Burk, Courtesy of SOM

© Dave Burk, Courtesy of SOM

© Kim Eriksson, Courtesy of SOM

© Dave Burk

Construction, 1967

Text by the Architects

875 North Michigan Avenue, formerly known as John Hancock Center, the world’s first mixed-use tower, is an architectural icon representing the close collaboration between architect Bruce Graham and structural engineer Fazlur Khan. The building remains an archetype for the collaborative ideal that continues to make SOM a leader in a wide spectrum of design disciplines.

Known locally as “Big John,” the tower is situated on North Michigan Avenue in a prestigious district with expensive apartments, shops, offices, hotels, restaurants, and art galleries. The wish to continue this mixture initially gave rise to the idea of building a 70-story apartment tower and a 45-story office tower. But the two towers would have occupied most of the site and would have impaired each other’s privacy and daylight conditions. Moreover, the lower-level apartments would have suffered from noise nuisance from the street. Therefore, it was decided to construct a single tower where the offices would be on the lower floors and the apartments on the higher levels.

The tower’s tapered shape was chosen to match the different floor space requirements that decrease from bottom to top — from the entrance and commercial zones at the base to the clusters of small apartments at medium height and finally to the large apartments on top, where relatively less space is needed for ancillary rooms with artificial lighting.

Structurally, the steel frame’s exterior members represent a tube where the necessary stiffness is provided by diagonal members and those structural floors that coincide with the diagonals’ intersections and the corner columns. In keeping with the functional organization, this tubular body has its largest cross-section where the stresses caused by wind forces are greatest. Steel consumption, amounting to about 30-pounds-per-square-foot of floor space, was no greater than for a 50-story conventional tower.

History of the John Hancock Center

The project, which would become the world’s second tallest building at the opening, was conceived and owned by Jerry Wolman in late 1964. The project was financed by John Hancock Mutual Life Insurance Company. Construction of the tower was interrupted in 1967 due to a flaw in an innovative engineering method used to pour concrete in stages, which was discovered when the building was 20 stories high.

The engineers were getting the same soil settlements for the 20 stories that had been built as what they had expected for the entire 99 stories. This forced the owner to stop development until the engineering problem could be resolved, resulting in a credit crunch. The situation is similar to the one faced during the construction of 111 West Wacker, then known as the Waterview Tower. Wolman’s bankruptcy resulted in John Hancock taking over the project, which retained the original design, architect, engineer, and main contractor.

The building’s first resident was Ray Heckla, the original building engineer responsible for the residential floors from 44 to 92. Heckla moved his family in April 1969, before the building was completed.

The Chicago Skyscraper Plans

John Hancock Center Floor Plans

John Hancock Center Image Gallery

About SOM

Skidmore, Owings & Merrill (SOM) is a global architectural, urban planning, and engineering firm. It was founded in Chicago in 1936 by Louis Skidmore and Nathaniel Owings. In 1939, they were joined by engineer John O. Merrill. The firm opened its second office, in New York City, in 1937 and has since expanded all over the world.
Works from SOM 

1. Structural Engineer: Skidmore Owings & Merrill
2. Contractor: Tishman Construction

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