Construction Begins on New Interstate 270 Bridge

Feb. 24, 2023
The estimated completion date is 2025

Good news for residents in the St. Louis metropolitan area: construction is beginning on the new Chain of Rocks Bridge over the Mississippi River.

The Missouri Department of Transportation (MODOT) recently blocked off the ramp from Riverview Drive in St. Louis to eastbound Interstate 270 to build a new interchange. The ramp will be closed for a year, signaling the beginning of construction on the bridge.

The Chain of Rocks Bridge is owned by both Missouri and Illinois. The two states have been planning a replacement for years once funding was available.

“The first substructures (for the bridge) are expected to be poured later in February,” MODOT officials stated last week when announcing the ramp closure.

Walsh Contractors is the contractor on the project, and they have been preparing for construction on the river's bank.

The new bridge will be “twin” bridges, one on the same alignment as the existing bridge and one directly south of it, according to the Illinois Department of Transportation (IDOT).

The existing bridge has 1-foot-wide shoulders that makes it more difficult for first responders to reach accidents quickly. Plans call for wide shoulders on either side of the new bridge’s four lanes.

“While I-270 is currently four lanes, MODOT has completed a study for I-270 in Missouri that proposed expanding I-270 to six lanes up to Riverview Drive in Missouri,” according to IDOT's overview of the project.

I-270 is a major freight hauling route in a region that has become a hub for distribution. Widening the lanes would help with traffic congestion on the route.

By 2018, IDOT was reporting that an average 51,000 vehicles were crossing the bridge each day, which is more than it was originally designed to handle. IDOT is the lead agency in construction of the new bridge. In 2020, the estimated cost of the bridge was $246 million with a completion date of 2025.

MODOT closed the eastbound ramp from Riverview Drive at 7 A.M. Tuesday. Travelers now have to take a detour that is approximately 2 miles.