A bridge being rehabilitated as part of a $63-million improvement project along Interstate 55 in Missouri will need an expensive fix after a demolition subcontractor removing the road surface did significant damage to the span's structural steel girders.

The cost to repair the bridge, which is one of 13 pairs of bridges undergoing rehabilitation on I-55 between Lindbergh, Mo., and I-44 in St. Louis, will be at least $10 million, according to Tom Huster, president of KCI Construction of St. Louis, which is the contractor.

Huster declined to name the subcontractor, who is no longer working on the project. He says the subcontractor used a breaker hammer during demolition work, which resulted in damage to some of the bridge's 80 girders, delaying the project.

“Currently engineers are completing design work to replace the damaged girders on the northbound I-55 bridge over the Union Pacific Railroad,” says Marie Elliott, a spokesperson for the Missouri Dept. of Transportation (MoDOT). “The replacement girders should be delivered this fall.”

Work started on the bridges between the Missouri towns of River Des Peres and Loughborough in March 2023, and was slated to be completed in 2024. MoDOT reported in November 2023 that girders on a northbound section of the Union Pacific Railroad bridge, just south of Loughborough Avenue, had been damaged in October.  

At the time, Tom Evers, an assistant district engineer for MoDOT, said the subcontractor had also used a breaker hammer on five other bridges, but those were determined to not have suffered any damage. 

The bridge work included removing and replacing the existing driving surface. The bridge girders were to be kept in place to support the new surface. 

Because they can't mix old and new girders, Huster says all of the girders will need to be replaced on the bridge. “We can’t replace girders here and there. We have to replace even ones that weren’t damaged. It's a long bridge," he says. 

The question of who will pay is still being sorted out. “It’s being worked out between us, the subcontractor, insurance and lawyers,” Huster says. “It’s messy.” He said the taxpayer-financed project will not see an increase in cost because of the mistake.

In addition, MoDOT is currently working through the necessary agreements with the railroad to install the girders once they arrive. 

Huster says his company is continuing to move forward with work, but exactly when the project is completed will depend on various factors including when the new girders are received. “We’re working to minimize delays,” he says. “We are expediting work as much as we can.” 

Work on both the north and southbound railroad bridge cannot proceed until the new girders are received, he notes. “The project is ongoing,” Elliott says. “We are focused on getting the girders in.” 

“Since the girders were not projected to be replaced during this project, the time it takes for them to be manufactured, delivered, and installed was not in the original construction schedule,” a MoDOT news release states. 

MoDOT is estimating that given current supply chain timelines and permitting requirements over the railroad, the northbound lanes could remain closed through 2024. This extends the expected completion date of the project into 2025.

The issues on the bridge do not impact the work continuing on I-55 to the north and south of the work area, she says.