Construction is expected to take three years, director of design and construction Rob Jones tells GlobeSt.com, and is slated to start next spring. The job includes demolishing the current Goodman Theater and replacing it with a glass, steel and limestone structure facing Monroe St. The 19th-century museum is at 111 S. Michigan Ave., with its front entrance facing the end of Adams Street.

The Art Institute of Chicago began raising more than $100 million for the project in early 2003. It also is selling buildings on Jeweler's Row. Designed by Renzo Piano, the addition will be topped with a "flying carpet," a luminous sun screen that will appear to float above the building.

"I think it's a zany looking building," says 42nd Ward Alderman Burton Natarus. "I think this is very fine architecture. I think it'd be nifty, though if Aladdin were on top of it."

The addition will include 65,000 sf of gallery space, as well as a retail Museum Shop along Monroe Street, Jones says. The museum's educational operations would use 20,000 sf. The basement of the addition will be used by the museum's mechanical systems. An 11,780-sf rooftop garden designed by landscape architect Kathryn Gustafson also is planned as part of the addition.

Plan commission approval is required under the city's lakefront protection laws.