Traffic is flowing again over the Johnson River bridge south of Delta Junction, now that the Alaska Department of Transportation and Public Facilities has completed repairs on Tuesday. DOT plans to replace the 81-year-old bridge on the Alaska Highway south of Delta Junction five years from now. Until then, the agency will keep sending crews to fix it.
It only took a day for DOT to get traffic moving again by re-attaching a steel plate that covered one of the bridge’s expansion joints. That’s a gap between two sections of concrete on the bridge deck that’s engineered to let the sections move slightly to handle things like heavy loads or earthquakes.
“An expansion joint pretty much just accommodates the expansion and contraction of bridge materials caused by temperature changes or vehicle weight,” says DOT spokesperson Angelica Stabs. She says expansion joints help bridges handle those stresses.
“We don't want our bridges to be really rigid. We want them to flex a little bit,” she said.
But expansion joints weren’t the problem that required DOT to close one lane of traffic Monday and part of Tuesday during repair work. It was the big steel plate that covered one of the joints.
“So this was not a scheduled repair,” Stabs said. “And, after some wear and tear after being on there for a while, the steel plate that covers that expansion joint came loose.”
It’s not unusual for a structure that was built in 1944 to need repairs.
“That bridge is a bit old,” she said. “so after a little while it (the steel plate) became loose, and we were just laying it back down as a temporary measure as we move forward and try to find some permanent repairs.”
The ultimate permanent repair will come in the form of a new bridge. DOT officials said they hoped to start work on the structure early this year. But Stabs says the plan now is to launch the project in a couple of years.
A DOT document released in March sets the estimated cost of the new bridge at 22-point-4 million dollars.
Stabs said once the first project is underway, DOT wants to begin work on a couple of other old bridges along that stretch of the Alaska Highway. She said the Gerstle River bridge project is tentatively scheduled to begin in 2029. Work on the Robertson River bridge would then begin in 2030. Stabs says each project will take about three years to complete.
