Yakima River Bridges Cle Elum to Ellensburg EB & WB Deck Rehab

Interstate 90 (I-90) is a transcontinental interstate highway that runs from Seattle, WA, to Boston, MA. I-90 is the only interstate to cross Washington state from west to east, as well as the only one to connect the state’s two largest cities, Seattle and Spokane. I-90 crosses the Cascade Mountains at Snoqualmie Pass, one of the busiest mountain pass highways in the United States. Just 48 miles east of the pass are the Yakima River Bridges, which carry the eastbound and westbound lanes of I-90 over the Yakima River. The bridges were showing signs of deterioration, including numerous full depth holes in the decks that had been temporarily repaired over a span of decades. They required full-depth repair and resurfacing to maintain structural integrity, continue safe operation of the highway, and extend the life of the bridge.

The extensive nature of the required repairs necessitated removing traffic from the bridges to perform structural repairs to both the top and bottom flanges of the cast-in-place girders. Graham installed temporary bridges and detours at both locations to re-route traffic off the bridges during construction. The repair work included installation of temporary shoring for the bridge substructure, removal and replacement of the bridge deck, and localized carbon-fiber reinforcement of the bottom of the girders.

During the first summer season, a local operator’s union strike shut down the project for a month, delaying the installation of the piles for the temporary bridges. As the Yakima River is fish bearing, in-water work is only allowed during a designated fish window, and the delay due to the strike threatened to halt the project for an entire year until the next in-water window. Graham partnered with WSDOT to develop a schedule recovery plan that included application for a subsequent in-water work window. Through significant coordination with the Washington Department of Fish and Wildlife, the additional in-water window was approved and Graham was able to complete the piling in the same year.

Graham opened the bridges to traffic in August 2020. The next summer season, crews were remobilized to remove the temporary bridges and detours.