‘Preventative measure’ intended to reduce wear and tear
The state Department of Transportation and Public Facilities has imposed weight restrictions on two old bridges on the Richardson and Parks highways. State officials say that’s to protect them from being damaged by heavily loaded trucks that pull two or more trailers.
A DOT public notice posted last Wednesday says only one so-called long combination vehicle will be allowed to cross the Big Delta bridge near Delta Junction and the Rex Bridge near Nenana at a time. The change went into effect immediately.
DOT spokesperson Angelica Stabs says the Rex Bridge, which spans the Nenana River, was showing signs of wear and tear.
“ The Nenana River Bridge on the Parks has had like numerous modifications and strengthening repairs,” she said. “And so we're getting ready to replace that.”
Stabs said DOT plans to solicit bids for the project next year to get a sense of how much it’ll cost to replace the bridge, built in 1963. She says it’s estimated at about 60-million dollars.
No problems have been detected on the Big Delta Bridge, which was built in 1966.
“While the Delta Bridge doesn't currently need repair repairs or any replacements,” she said, “this posting is just a preventative measure to avoid problems we're seeing at Rex, since they are both built in the same era and they have similar designs.”
Both bridges have steel-frame structures above the roadway deck called overhead trusses that distribute the weight of vehicles on the bridge. Signs posted on the bridges state that only one long combination vehicle is allowed at a time. Stabs says that’s because more than one could put too much weight on longer spans that are supported by concrete structures the bridge is built on.
“On these bridges, we have long spans on some trusses, and so when we have more than one truck on this bridge at a time, it just causes some strain.”
A long combination vehicle typically weighs at least 40 tons. But some rigs weigh more, like the Black Gold Transport ore-hauling trucks, which travel over the Big Delta bridge that can weigh twice as much when fully loaded with gold ore extracted from a mine near Tetlin.
