ST. LOUIS – IDOT will host an open house meeting Wednesday detailing the plan to replace the Chain of Rocks Bridge between north St. Louis and Madison County, Illinois.

The project calls for two new twin bridges to be built side by side replacing the current Chain of Rocks Bridge that was built in 1966. It is now approaching the end of its lifespan. IDOT said as the bridge has gotten older, more repairs have become necessary, and the roadway geometrics are now sub-standard. Traffic has also increased significantly from just under 20,000 vehicles per day in 1975 to over 51,000 vehicles per day.

IDOT said one of the two new side-by-side bridges will replace the current Chain of Rocks Bridge. The other one will be just to the south of the existing bridge. The new bridges will have wider shoulders and will also accommodate a possible future expansion of 270 being proposed by MoDOT. IDOT said while there will be some lane closures during construction, the plan is to keep four lanes of traffic open. FOX 2 was told the southern bridge will be built first. Then, the current bridge will be demolished and a new bridge will be built in its place. MoDOT’s changes to the Riverview Drive interchange will be done at the same time.

Wednesday’s open house will be at the Granite City Campus of Southwestern Illinois College on Maryville Road from 4 p.m. to 7 p.m. There is no formal presentation, so anyone can stop by anytime. Exact construction timelines are still in the works.