The project involves the construction of a new eight-span bridge over the Illinois River and demolition of the existing structure. The existing structure was constructed in 1934 and when inspected in 2012, was deemed “structurally deficient” with a rating of 32.2 out of 100.
This is a multi-year project that requires working around always-changing river levels and conditions in the Illinois River Valley. The space surrounding the project is significantly limited by burial grounds, marina and grain elevator operations and the existing bridge near the newly constructed structure. Other complexities include managing delivery logistics of more than 100 structural steel girders, the largest of which are 135 feet long and nine feet high.
Once completed, the new bridge will be 1,800 feet long, 40 feet wide; an eight-span structure with nine-foot tall girders. It will consist of approximately five million pounds of structural steel and 10,000 cubic yards of concrete
- New embankments at the north and south abutments
- Drilled shafts for four bridge piers up to 80 feet deep
- Cofferdam installation for seven bridge piers
- Cofferdam excavation and dewatering utilizing clamming methods, long-reach excavators and dredging equipment
- Mass concrete at five piers for the drilled shafts, footings, pier stems and pier caps
- Structural steel installation, including the setting of eight spans with nine-foot-tall girders on the center span and five-foot-tall girders on the outer spans; longest span 230 feet
- Demolition of the existing structure included of the removal of the concrete deck with traditional equipment followed by engineered controlled explosives to drop the structure to the water below, where it was cut apart into manageable sections and pulled onto barges.