US 12 Wildcat Creek Bridge – Replace Bridge

Location: Rimrock, WA

U.S. Route 12 (US 12) is a major east-west U.S. Highway, running from Aberdeen, WA, to Detroit, MI. The highway crosses the Cascade Range over White Pass, south of Mount Rainier National Park, providing an important transportation link for Washington residents. Near Rimrock, WA, the highway crossing structure over Wildcat Creek had been around since 1936. It was no longer feasible to continue patching the large holes forming in the 82-year-old bridge deck – the bridge needed to be replaced.

The Graham Design-Build team developed an innovative bridge design that minimized traffic, community, and environmental impacts by using a 54-ft buried precast arch culvert structure instead of the standard WSDOT girder bridge. The precast arch design accelerated the bridge replacement timeline allowing Graham to replace the bridge in just 17 days. With this reduction in construction schedule, Graham was able to utilize an existing US Forest Service road to detour traffic over Wildcat Creek, eliminating the need for construction of a temporary bridge. This approach exceeded WSDOT’s expectation for an accelerated schedule to eliminate highway lane closures and minimize impacts to motorists on this major mountain pass. Graham eliminated four and a half months of ongoing impacts to motorists and 90% of proposed tree and vegetation removals, at a cost savings of over $4M to WSDOT.

Contract Value


Prime Consultant

Stantec Inc.

Project Owner


Contract Format


Completion Date

November, 2018

Contract Duration

7 months