South Spokane Street Viaduct Deck Rehabilitation

Updated October 16, 2024

We officially finished our work on the South Spokane Street Viaduct Deck Rehabilitation

Between July and October 2024, we repaired all of the damaged pavement on the deck’s surface, which was prone to potholes and “alligator skin” cracking. Crews repaved the bridge deck with a synthetic polyester concrete to help ensure it remains in good condition over time. We also made drainage improvements and bridge deck repairs on the westbound lanes.   

Project Background  

As its name suggests, the Spokane Street Viaduct (or the SSV) sits above South Spokane Street. The Viaduct was first built in the 1920s. Back then, it was one of only two road connections between West Seattle and downtown.  

The SSV is important to Seattle's transportation network. The Viaduct literally helps connect West Seattle to the rest of the city: people leaving Interstate 5 (I-5) use the SSV to enter the West Seattle Bridge and the Spokane Street Swing Bridge (aka the Low Bridge). Large, heavy vehicles travel across the bridge every day. Think heavy freight vehicles, buses, and hundreds and hundreds of cars. Add wet weather conditions to this equation and the wear and tear is inevitable.  

What did we do? (Project Overview) 

To keep the SSV in good shape, we dedicated the money, time, and labor to repair the road surface. The road surface (or what we call the deck) bears the weight of numerous cars, buses, and trucks. To ensure that the deck can handle this load, our Deck Rehabilitation project replaced the existing surface and fixed these cracks with a stronger and more durable top layer of polyester coating. First, we ground down the old road's surface. Then we blasted that exposed road to give it a coarser texture. That coarseness helped the polyester coating stick better. Then we applied the polyester overlay. All three eastbound lanes received this treatment and we also did spot repairs on the westbound lanes.   

We also updated the scuppers. Scuppers are the openings on the bottom of the bridge’s median barriers that let rain or other water drain off the road surface. We need those in good working condition so that people can safely drive. 

The majority of our work occurred overnight during weekdays and during weekends. We appreciate your patience as we completed the work. 

Funding  

This work was funded by a $7.5 million federal grant from the Federal Highway Administration Bridge Improvement Program - which was funded in part by the Bipartisan Infrastructure Law and then passed to the WSDOT’s Local Bridge Program.