A Sightseer's Guide to EngineeringNational Society of Professional EngineersNational Engineer's Week
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From the top of the Sears Tower you can see four states--Illinois, Indiana, Wisconsin, and Michigan--on a clear day. When you’re up there, the building can sway about 6 inches from true center. And how do they keep the approximately 16,100 bronze-tinted windows clean? Six roof-mounted robotic window washing machines--designed by engineers--do it.


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© 2010 NSPE. A Sightseer's Guide to Engineering | Disclaimer | Contact: Stacey Ober, pr@nspe.org, at 703-684-2815
ILLINOIS Printable version
Sears Tower
233 S. Wacker Dr.
Chicago, IL 60606

Web Site
Go up to the Sky Deck on some of the world’s fastest elevators and take in the view. 
Hours of Operation: 10 a.m - 10 p.m., May - September and 10 a.m. - 8 p.m., October - April Need a map?
Structural engineers have a challenge designing skyscrapers in Chicago--the famous strong winds want to blow the buildings down. To keep skyscrapers standing, engineers need to find the right balance between a rigid structure, which won’t sway in the wind and make people sick, and one flexible enough not to snap like a stick. The Sears Tower is another monument to that design know-how. Opened in 1973, it rises 1,454 feet high and is the second tallest building in the world--and the tallest if one considers the highest occupiable space as the criterion. It took three years to build at a cost in excess of $150 million.
 
Who Made It: Structural Engineer--Fazlur Rahman Khan
 
Photo Credit: Courtesy Sears Tower Skydeck