“This job is to rehabilitate the existing I-255 bridges over the Mississippi River,” says Christopher Morgan, MoDOT Resident Engineer for the South-West St. Louis County area.
The westbound bridge was built in 1985 and the eastbound, into Illinois, in 1993. In the last few years, inspectors found failed expansion joints and weld cracking. The department made some emergency closures and repairs, but the bridges needed rehabilitation to remain serviceable and in good condition in the years ahead.
About 31,800 vehicles travel on the eastbound bridge on average and 33,200 on the westbound structure. Trucks comprise 18.2 percent of the traffic.
Wiss, Janney, Elstner Associates of Northbrook, Illinois, designed the bridge modifications and repairs. Civil Design of St. Louis, Missouri, designed the roadway, primarily traffic control, and bypass. KCI Construction of St. Louis, Missouri, received the rehabilitation contract with a notice to proceed on January 3, 2022.
“KCI has been good to work with on this project,” Morgan says. “We’ve been able to work together to adapt quickly to all of the unexpected things we’ve discovered so far.”
Ethan Renner, Project Manager for KCI agrees, saying, “Our team has done a good job of working together, coordinating and keeping open communication, both internally and with MoDOT. It’s going well.”
“Our superintendent Ken Recar has done a great job with all of the daily coordination required to keep all work moving forward,” Renner says.
The river bridge work includes removing the existing paint and repainting of the bridges. About 284,000 square feet per bridge are to be painted. Containing the blast residue has been the biggest environmental concern on the project. Crews built a steel skeleton around the bridge part being worked on and placed white tarps over that area.
“Thomas Industrial Coatings of Pevely, Missouri, has done a great job so far with all of the work under the deck, and Liberty Maintenance of Youngstown, Ohio, put together a very good encapsulation of the tied arch,” Morgan says.
The work also required demolishing and then replacing 306 linear feet of expansion joints with beefed up joints poured in with ultra-high performance concrete (UHPC), with 18,000 to 24,000 psi strength.
“The UHPC is more fluid than typical concrete, so the formwork on these joints gets a little more complicated. Everything has to be sealed very tight,” Renner says.
The project also includes inspecting 4,500 linear feet of welds per bridge and where needed, either welding or repairing; fixing catwalks and lighting; replacing six cables in the tied arch; and metalizing the bottom 25 feet of the remaining cables, where they get splashed by salt in the winter.
“We haven’t begun that work yet, but the application of the metalizing to the existing cables is a bit unique and will be interesting to watch,” Morgan says.
Crews also are milling and overlaying the existing deck surface with polyester concrete on the eastbound bridge and latex modified concrete on the westbound structure.
“We used a couple of innovative items,” Morgan says. “This would be the polyester concrete overlay being used on the eastbound bridge and the UHPC used on the joints. We believe the polyester concrete overlay being used on these will help extend the life of the bridge and reduce future maintenance. In addition, we were able to obtain additional federal cost share by including them in the project.”
Although there is no foundation work, the project includes some half-sole substructure repairs on the river bridges. Those bridges have steel plate girders for the approaches and steel tied arches for the navigation span.
Crews are working on the eastbound bridge this year. “This first year is a big push to get the eastbound bridge done before winter,” Morgan says.
KCI will start on the westbound structure in April 2023. The scope of work is mostly the same, but crews will be replacing six of the cable hangers on the westbound bridge. That will entail jacking and shoring to take out the old hangers and install the new ones. The top of the arch is 180 feet above the bridge deck. KCI will deploy some 180-foot man lifts during that work.
Traffic on the bridges is reduced from three lanes to two narrower, 11-foot lanes in each direction and is diverted to one bridge while the rehab work is being completed on the other. The traffic lanes are separated with a concrete barrier wall. Crews have built bypasses on both sides of the river.
“One of our biggest challenges has been maintaining the bypass traffic on the westbound bridge,” Morgan says. “The two westbound – two eastbound lane configuration has worked really well with minimal congestion.”
Also, traffic is driving over the existing deck drain grates on the shoulders of the westbound river bridge. When there have been loose or broken grate on the river bridge, the team has had to repair or replace them and reduce traffic to one through lane in a direction. Morgan reports seeing significant backups with the restricted lanes when reducing the lanes during those repairs. “We’ve had several we’ve had to repair or replace,” Morgan says.
The job required removing the existing asphalt surface on the Kock Road bridges and various repairs including patching the void tubes, which run the length of the bridge, and performing hydrodemolition – using high pressure water to locate bad concrete in need of repair. Crews will chip out the bad concrete and replace it.
During paving, crews will use new latex-modified concrete overlays and new barrier curbs, Morgan says. The Koch Road bridges have voided concrete slabs.
“The condition of the existing deck surface of the westbound Koch Road bridge has caused a lot of needed repairs,” Morgan says.
The eastbound Koch Road bridge is currently fully closed during this year’s construction. In 2023, the westbound off ramp to Koch Road will be closed. Both closures require a detour to the next interchange west at Route 231, Telegraph Road.
When crews performed emergency repairs to a hole in the Koch Road bridge deck, traffic backups occurred.
The project is on schedule for completion by December 15, 2023. Morgan praises the work of MoDOT Senior Inspector Tyler Wolk and his collaboration with department and consulting inspectors and the contractor.
“I’m most proud of our team working on this project,” Morgan says. “We have been able to work well together keeping a common goal in mind.”
Photos courtesy of KCI Construction