SEQUIM — A $1.53 million project to construct a 750-foot-trestle over the Dungeness River requires crews to navigate thick woodlands and cross the waterway without disturbing wildlife, said the president of the construction company performing the work.
Crews with Nordland Construction NW of Port Townsend began removing a damaged trestle from the west side of Railroad Bridge on Monday in preparation for replacing it and reopening the link on the Olympic Discovery Trail.
About 30 percent of the present 570-foot-long wooden trestle had been removed as of Wednesday, said Thomas Johnson, president of Nordland Construction, which is using design and engineering schematics by Otak of Portland, Ore.
The trestle will replace the existing one on the bridge in Railroad Bridge Park, 2151 W. Hendrickson Road, which was damaged by the rain-swollen Dungeness River during a Feb. 6 storm.
The bridge itself is undamaged, but traffic over it has been closed since February because the trestle connecting it to the west bank is unsafe. That blocked use of a portion of the 140-mile Olympic Discovery Trail, which will eventually span the North Olympic Peninsula from Port Townsend to LaPush.
The Jamestown S’Klallam tribe owns both the park and the bridge, and recently received the permits required to begin construction on a replacement.
The bridge is expected to be reopened after work is completed in December.
Crews are taking special measures to do the work without disturbing salmon and other wildlife.
“We are going to make another 800-foot access road to the side of the perimeter alignment,” Johnson said, noting that the current pathway on the west side of the river is not large enough to accommodate large machinery.
The temporary roadway will include an 89-foot-long railroad car bridge that will span the river channel, allowing machinery to move across and onto an island in the center without entering the waterway.
“We have to be extremely careful about disturbing any spawning salmon,” said Pat McCullough, owner of ESA Inc. of Belfair and subconsultant to Otak.
The temporary bridge will be set using a small crane, he said.
Once the new roadway is in place and the old trestle has been completely removed, crews will begin driving steel pilings that will support the new trestle into the ground at four locations.
Concrete piers will be placed on top of the pilings to hold up the trestle.
The piers will be about 50 feet long and consist of 16.5-inch walls, McCullough said.
A concrete pier beneath the existing Howe Truss bridge will support the new trestle where the two structures connect.
The final phase will be to lower a walkway onto the piers with two massive cranes, McCullough said.
“I imagine it will be at least two 200-ton cranes — one on each side” of the river channel, he said.
The new trestle will arrive in prefabricated 60-foot-long, 9-foot-deep sections, and crews “will bolt them together,” McCullough said.
The new trestle will be longer than the existing one and includes four 182-foot-long sections with one 22-foot-long section in the middle.
The old trestle previously was propped up in 38 areas by five creosote poles in each location. The depth of the pilings varies from 6 feet to 25 feet.
All 33 remaining creosote supports from the river bed will be removed. Five were removed previously in early August.
The replacement trestle will allow logs and migrating salmon to pass beneath without hindrance by reducing the number of support beams needed to prop up the walkway to four.
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Sequim-Dungeness Valley Editor Chris McDaniel can be reached at 360-681-2390, ext. 5052, or cmcdaniel@peninsuladailynews.com.