SR 508 - S Fork Newaukum River Bridge Replacement - Complete Spring 2020

Project news

  • On Tuesday, April 24, 2018, crews begin work to replace the historic South Fork Newaukum River Bridge with a new two-lane concrete bridge.
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Project overview

This project will remove the aging South Fork Newaukum River Bridge that is located on State Route 508, five miles east of Onalaska, which carries approximately 1,400 vehicles a day.

As part of the replacement project, the Washington State Department of Transportation is giving away the historic structure. The bridge is one of only 13 pony truss bridges over 50 years old remaining in use on public roadways or recreation trails in Washington.

The bridge, measuring 197-feet in length, consists of a six-panel, riveted-steel 90-foot main span Warren pony truss with verticals. The trusses are comprised of fabricated steel shapes, including channels, angles and plates.

To keep existing traffic moving through the area, WSDOT maintenance crews built a temporary single-lane Bailey bridge in January 2015. Traffic will continue to utilize the temporary Bailey bridge until the new bridge is completed.

Why is WSDOT replacing the South Fork Newaukum River Bridge?

The existing bridge was built in 1930 and is now structurally deficient and functionally obsolete.

The End Result
The new bridge will provide users of SR 508 a safe and structurally sound bridge over the South Fork Newaukum River and meets current engineering and safety standards.

Needs & benefits

A new bridge will provide reliable transportation on State Route 508 in Lewis County.


  • Winter 2017: Project goes to bid for construction.
  • Feb. 12, 2018: Construction contract awarded to Oregon State Bridge Construction Inc.
  • Tuesday, April 24, 2018: Construction begain.
  • Spring 2020: Construction scheduled for completion.


Joanna Lowrey
WSDOT Project Engineer
Phone: 360-442-1350 or toll free 1-800-545-1393 Email:

Tamara Greenwell
WSDOT Communications
Phone: 360-905-2056