MEDFORD, Ore. – Thousands of bridges across the country are in need of major repair or replacement, and while Oregon is better than most states, transportation workers say there is still more work to do.
The Oregon Department of Transportation is working to repair a number of aging bridges that are beginning to show more wear and tear, including thousands that are considered “structurally deficient” or “fracture critical.” The terms refer to red flags in regard to a bridge’s age, width, height, the amount of cracking, strength of its support beams, and other criteria.
According to the most recent data from the National Bridge Inventory, Oregon has 1,774 deficient bridges, which is fewer than other states in the U.S. An Associated Press Report found 65,000 nationwide were structurally deficient, and more than 20,000 were fracture critical.
Bridges are inspected every two years, and are assigned a number from 0 to 100 representing how structurally sound it is. Notable bridges in the Rogue Valley that rated low were older bridges built in the 1950s and ‘60s. Tolo Bridge over Interstate 5, which was built in 1955, was rated 35. Table Rock Road bridge over I-5, built in 1961, rated 34. East Main Street over I-5 in Ashland, built in 1962, rated 13.
ODOT officials said this does not necessarily mean the bridges are unsafe, but it does mean that the structures are reaching the end of their intended lifespans, and need work done to repair cracks and bring them closer to the current code.
“[We need to] tighten those bridges and get as much life out of them as we can,” said Gary Leaming with ODOT public affairs. “But down the road we’re going to need to see more repairs or replacements on a lot of the bridges.”
Engineers said a major sign that a bridge is becoming unsafe is when a weight limit is posted. The Fern Valley Road Bridge in Phoenix was given a weight limit to try to extend the bridge’s life, and is scheduled to be replaced when the new interchange is built next year.
A recent bonding project allowed ODOT to repair many major bridges along important freight routes, which is why many bridges on Interstate 5 in southern Oregon, including the Medford viaduct, rated in the 80s and 90s.
“We couldn’t do all of the bridges that needed repair, but we did do a lot of bridges on these critical freight routs to keep traffic moving,” Leaming said.
But Leaming warned that ODOT is “getting behind the curve” when it comes to repairing the older bridges, and said eventually those aging bridges will need to be replaced. He said part of what is causing problems is the increasing weight of freight trucks. Leaming said that in the 1960s truck freight typically weighed about 80,000 pounds. Today, he said, freight tends to weigh closer to 105,000 pounds.
“When these were built 50 years ago we weren’t running the weights that we’re running on them today,” he said.
Replacing the bridges is easier said than done. According to Jackson County Engineer Mike Kuntz, it costs between $1 million and $2 million to replace an average bridge. Kuntz said the price tag makes it hard for local agencies to budget for. He said roads departments across the country are faced with a similar dilemma.
“If you don’t take care of it, eventually it goes,” Kuntz said. “And it costs trillions of dollars [nationwide] to put it back.”