Salt Creek Tunnel Viaduct

DOWL began working on this project in the summer of 2014 with the project already partially constructed. As a trusted partner, DOWL was directly hired by the Oregon Department of Transportation to get the project back on track by reevaluating the design and producing a new design package that could be bid and under construction by the spring of 2015.

The scope of improvements for this project included completing the construction of two partially completed bridges; replacing two half viaducts with new bridge structures on each side of the tunnel; rehabilitating and seismically upgrading a historic electrical power room built integrally underneath the existing bridge; constructing a new retaining wall; electrical upgrades; guardrail modifications; stormwater design; and signing, paving, and striping.

This is a historic structure, originally constructed in 1938, located in challenging terrain on OR 58, also known as the Willamette Highway. The existing structures were severely deteriorated and in need of replacement. OR 58 serves a major freight route between central Oregon and the Willamette Valley. To maintain traffic, DOWL carefully redesigned the construction staging to allow partial demolition of the existing structure while still maintaining one lane of travel during daytime hours throughout construction.

An accelerated design schedule and a deep team of talented engineers allowed DOWL to meet the delivery goals while maintaining technical excellence and providing a high-quality set of plans and specifications. The project successfully bid in February of 2015 — less than six months after DOWL received notice-to-proceed on our design contract.