The Sears Tower construction crews broke ground in 1970 and the building topped off in 1973 becoming the tallest building in the United States, a title that stood for about 25 years. The Venerable architectural firm of Skidmore, Owings and Merril took on project led by architect Bruce Graham and architectural engineer, Fazlur Khan. Khan invented a construction technique utilizing construction tubes. The Sears Tower is actually nine buildings connected to the main tower by Khan’s tubes. Kahn’s engineering brilliance lives on. There is not a skyscraper in the world that doesn’t tip a hat to the engineer.
Sears was once the retail king/queen of the world – the Amazon of shopping in the 1970s, 1980s and 1990s. . As its business model faded so did its need for office space and the company eventually ended up leaving the legacy landmark. United Airlines is now the largest tenant. Trivia. There are 40,000 fire detectors in the building.
The Sears Tower has a little brother named “Big John” also known as the John Hancock Building. Same architect, same architectural engineer and agency. The Hancock topped off in 1969. Construction on the Sears started in 1970.
Chicago is rich in great architecture, but the Sears Tower and the John Hancock continue to serve as the most identifiable buildings in the city and perhaps the country. Here’s to courage, ingenuity and risk taking in world class Chicago architecture.