Kellogg Boulevard in St. Paul is only about one mile long, but it's a bit of an engineering marvel made up of 10 separate bridges that zipper downtown to the bluffs of the Mississippi River.
Now two of those aging bridges need replacing at an estimated cost of nearly $120 million.
City engineers are preparing to replace the Kellogg/Third Street bridge on the east edge of downtown with the help of state and federal funding. Demolition of the existing bridge and construction is scheduled to start in early 2023 and close the span for two years.
The city is now asking state lawmakers for more aid this year to replace the eastbound Kellogg RiverCentre Bridge on the other side of downtown, with hopes of also starting construction next year. City officials say replacing this 86-year-old span, which includes a viaduct that tunnels through the bluffs adjacent to the convention center, is now a top bonding priority.
Both bridges have reached their end of life and have been deemed structurally deficient, forcing the city to enforce weight restrictions in recent years. City staff say new bridges are critical to keep downtown connected to the rest of the Capital City. They say the new spans include improved trails for cyclists and pedestrians.
"We assessed the condition of the bridge. With the structural degradation, the concrete degradation and the corrosion of the steel, we would just be patching things up if we tried to repair it. It has to be replaced," said Dag Dejene, city of St. Paul civil engineer overseeing the RiverCentre bridge replacement.
Fundingis just part of the challenge. Crews must work around a host of obstacles.
The Kellogg/Third Street bridge is the longest city-owned bridge measuring more than 2,100 feet long, said Brent Christensen, a city of St. Paul civil engineer overseeing the bridge replacement.