Aon Building
Problem
Towering over Lake Michigan, the 90-story Aon Building was built in 1973. In order to keep the windows clean and the facade maintained, a train-like house rig was installed on the roof that runs along an elevated rail track so that a swing stage can be lowered to access any inch of the building. After 35 years, the house rig needed replacement, and the elevated track and supporting posts required reinforcement to support its weight and to counteract deterioration.
Solution
- Removed concrete around each of the 102 4" diameter, heavy duty gauge steel posts supporting the elevated rail track to expose the original post connections
- Evaluated and coordinated welding repair of each post
- Painted and re-poured the concrete around each post
- Biggest challenge: getting up to the 90th floor with electric demolition tools and removing debris in small batches through the freight elevator, while President Elect Obama was using the building along with heightened Secret Service security
Details
Work
Concrete roof restoration for a house rig system
Location
Chicago, IL
Budget and Scope
Price: $220K; 102 repair locations
Owner
Jones Lang LaSalle
Architect/Engineer
Wiss, Janney, Elstner Associates, Inc.