Bowman is providing Phase III construction engineering services for the Mile-Long Bridge replacement. This multi-year project entails the construction of two entirely new twenty-seven span bridges to replace the
original structure, which was constructed in 1957. The new twin structures span the Illinois and Michigan Canal, Chicago Sanitary and Ship Canal, the DesPlaines River, the mainline CN R.R., and a UPS and BNSF R.R. intermodal freight facility.
Each of the new substructures is approximately 4800 feet long and consists of twenty-six reinforced concrete piers founded on drilled concrete shafts embedded into bedrock a minimum of six feet. The superstructure for each of the bridges will be a combination of ten-foot-deep steel girders over the CN R.R. and the two canals. The remaining twenty-three spans over the DesPlaines River and the intermodal facility will utilize long span 90 and 72 precast concrete girders. The superstructures are stainless steel reinforced cast in place concrete decks for longer service life. The deck cross-sections will be five lanes, each with a flex lane and full-width concrete shoulders. The structures are being constructed separately so that there are no lane reductions during construction to affect the high traffic volumes on the existing Tollway.