By Paul Gottlieb
Peninsula Daily News
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And they present a similar danger of failure, local officials said.
Here's the North Olympic Peninsula inventory of “through-truss” bridges — most on U.S. Highway 101 — in which trusses are above, not below, bridge decks, as outlined Friday by the state Department of Transportation and officials of both counties:
■ One is a collision-prone Clallam County bridge on Quillayute Road that crosses the Sol Duc River 4 miles west of Forks.
■ Six are state bridges that carry U.S. 101 over the Sol Duc and Calawah rivers in Clallam County's West End.
■ Two are U.S. 101 bridges that stretch across the Big Quilcene and Hoh rivers in East and West Jefferson County.
Also led by steel trusses — albeit modern ones — is the 1.5-mile Hood Canal Bridge, the third-longest floating bridge in the world that is split by Jefferson and Kitsap counties.
Installed in 2010, the entrance trusses to the floating span are considered modern engineering and are not accident-prone.
Like the I-5 bridge in Skagit, the old North Olympic Peninsula steel-truss bridges are considered functionally obsolete because they do not meet present-day volume and vertical-clearance standards, Transportation Regional Operations Engineer Chris Keegan said.
That doesn't mean they are unsafe, county and state officials said.
They are inspected by Transportation once every two years.
“Our bridges are in pretty good shape,” said Bob Martin, Clallam's public works administrative director and the county's former head of emergency services.
“Some need to be retrofitted to be seismically sound,” he added.
But the spans are not immune from the same consequences that befell the Skagit River bridge near Mount Vernon, county officials said.
An 18-wheel truck clipped an overhead truss on the bridge Thursday evening, collapsing a section of the span and dropping vehicles and people into the chilly river about 50 feet below.
“If they get hit in the same place as the Skagit River bridge got hit, they are likely going down,” County Engineer Ross Tyler said of Clallam's bridges.
“It's very critical for people who are hauling really tall loads to be aware of how high that is,” he added.
Jefferson County Engineer Monte Reinders said if the Big Quilcene River bridge on U.S. Highway 101 south of Quilcene went down, it would cut off critical access to Hood Canal towns.
“The thing about truss bridges is, every single member is critically important,” Reinders said.
On the West End, the Quillayute Road span has had more than its share of truck mishaps.
“That bridge has gotten hit a lot of times over the past 28 years that I've been here,” Tyler said, estimating bridge components have been replaced at least a half-dozen times during nearly three decades.
The bridge once carried the Olympic Highway — U.S. 101 — over the Sol Duc River until it was moved piece by piece to its current location around the 1960s, he said.
“It used to get hit regularly by high log-loads in the late '80s, when hauling was really, really heavy,” Tyler said.
Back then, there was a warning system on the bridge to warn of the 14-foot, 3-inch clearance.
Martin said the interstate standard for truck clearance is 16 feet, 6 inches, more than 2 feet higher than the Quillayute Road bridge.
“Nowadays, they don't haul those big loads of logs anymore, so it's not logs causing problems,” Tyler said.
A large truck clipped one of the bridge's cross-pieces in March, Tyler said.
The piece was replaced in April.
But it all depends on the location of impact.
“If it isn't braced, it's going to bend — and one way or the other, the whole house of cards falls, and the dominoes just collapse it,” Tyler said.
“Any truss like this will collapse.
“It just so happens that our Sol Duc River bridge [on Quillayute Road] was always hit in a member that is a bracing member.”
Martin said if any of the bridges on Highway 101 was disabled, emergency responders and West End residents would not be cut off from the inner Peninsula.
“There is an alternate route for emergency vehicles for any bridge that would collapse,” he said.
“The detours around would be pretty circuitous,” Martin added.
It's not uncommon for the state's bridges to get hit by trucks, Transportation spokeswoman Claudia Bingham Baker said.
“We do have bridge structures that get hit around the state, and it varies year by year,” she said.
But there's no guarantee a bridge won't collapse if a truck hits it a certain way.
“We can give [residents] the assurance that we regularly inspect our bridges and we maintain them so they are functionally sound, so they are structurally sound,” she said.
“If we believe a bridge has any kind of repair that's needed, we do that repair.”
Said Keegan, Transportation's regional engineer:
“We do all we can do to keep them well-maintained, and that's about the limit of what we can do.”
Senior Staff Writer Paul Gottlieb can be reached at 360-452-2345, ext. 5060, or at firstname.lastname@example.org.