For months, Thurston County Public Works inspectors have said a 1950s-era bridge riddled with cracks and sags on Littlerock Road Southwest was unsafe for heavy vehicles.
This month during demolition work, crews found proof that the bridge near 110th Avenue had already structurally failed, according to civil engineer Matt Unzelman .
“The reason it failed was due to scour,” he said. “The material washed out from one of the piers, and it settled.”
Even after crews made temporary repairs to the two-lane bridge, which the county inherited from the state, it didn’t meet current safety standards, Unzelman said.
“The bridge didn’t have any re-bar in it,” he said. “It was just concrete. ... It confirmed what we suspected all along.”
Last week, remnants of the old structure, known as the L-4 Bridge, were hauled away, and a crane began setting up a support system for its replacement. Construction manager Brandon Hicks said the new bridge, which will have a 71-foot span, is expected to open for vehicle traffic in six weeks, on Oct. 6. Work is expected to continue on the bridge after that date, but the goal is to have it ready for vehicle traffic in six weeks, he said.
The contractor, Active Construction of Tacoma, is working under a “very aggressive schedule” to meet that deadline, Hicks said. It will include long shifts and some night and weekend work, he said.
The $1.6 million bridge is being paid for with an emergency grant from the Federal Highway Bridge Program. While construction is going on, Salmon Creek is temporarily being routed through a 120-foot-long pipe, known as a stream bypass. Crews already have buried old stumps in the area to help prepare the habitat for the creek’s native Coho salmon.
“The whole goal is to have it ready for wildlife as soon as the bridge is done so that the fish can spawn,” Hicks said.
“This was a huge collaborative effort with (the state Department of) Fish & Wildlife,” Unzelman added.
A natural gas line was temporarily moved to the other side of the bridge so that it won’t be affected by the pile driving, Hicks said. Crews also had to find ways to work around other utilities such as electric and phone lines, cable and fiber optics, Unzelman said.
Hicks said there’s a high level of curiosity about the project, but he urges people to follow its progress on Thurston County Public Works’ website at www.co.thurston.wa.us/publicworks instead of visiting the construction zone.
“Obviously, with the old bridge gone, it’s impossible for people to drive through, but we actually have had several joggers and several bicyclists wander through, and we need to get the word out that the road is completely closed to everyone,” he said. “It’s for everyone’s safety.”