Located in the heart of downtown Chicago, this project was awarded in September 2006 to a Kiewit-led joint venture by the Chicago Transit Authority (CTA). The project is designed to create an easy, efficient method for passengers to travel to and from O’Hare and Midway airports by connecting CTA’s Red and Blue lines beneath Block 37.
The Block 37 project will connect the subway lines through excavations approximately 160 feet long by 50 feet wide. Excavation support methods include a slurry wall, H-piles and lagging. From the top of the existing CTA subway tubes, a concrete diaphragm slab will form the new tunnel roof followed by excavation to the invert and pouring of the new invert slab. The side of the existing tunnel will be demolished as well as an opening in the Block 37 slurry wall. Turnouts and track work will be placed, and finally the excavation will be backfilled and the streets repaved.
Eventually, travelers will be able to check their luggage at the Block 37 location, then ride an express train to their airport destination. Kiewit capitalized on its experience with cut and cover work in complex, densely urban areas in obtaining this contract.
The project is scheduled for completion in December 2008.