South Spokane Street Viaduct Deck Rehabilitation

Updated September 10, 2024

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 are we doing? (Project Overview) 

To keep the SSV in good shape, we are dedicating the money, time, and labor to repair the road surface. We want to make sure the road surface (or what we call the deck) can handle that volume of cars, buses, and trucks. This Deck Rehabilitation project will replace the existing surface and fix these cracks using a stronger and more durable top layer of polyester coating. 

We will also update the scuppers. Scuppers let rain or other water drain into inlets. They are the are openings on the bottom of the bridge’s median barriers. We need those in good working condition so that water can drain from the road surface, making it safer to drive. 

Why are we doing this work (now)? 

The best answer to the above question is that a LOT of vehicles cross the Viaduct daily. While the SSV has undergone repairs and expansions in recent years, the deck occasionally gets cracks or other damage from the traffic. Again, a lot of people use the viaduct daily. If we do this work now, we can avoid the road surface deteriorating sooner. 

How will we do it? 

First, we grind down the current road surface. Then we blast that exposed road to give it a coarser texture. That coarseness will help the polyester coating stick better. Then we apply the polyester overlay! All three eastbound lanes will receive this treatment. We will also be doing spot repairs on the westbound lanes.   

We will also update the scuppers. Scuppers are openings on the bottom of the bridge’s median barriers. A scupper lets rain or other water drain into inlets. Water can then drain from the road surface, making it safer to drive. 

There will overnight closures most weeknights as well as entire weekends. We do this to protect the work zone. Depending on the location of our current work zone, you will need to consult the table(s) below to see detours. 

When we’re doing it (Schedule) 

Construction Updates:  

Week 6 (September 9 - September 12, 2024): _{(*schedule is subject to change)} 

Detour Options: 

• Weeknight Lane Reductions (Sept 9-12, 2024):
  • If traveling northbound on I-5 and going toward West Seattle, take Exit 163. Remain on the one open lane on the Viaduct. Then enter Lower Spokane St. (i.e., the surface street). From there, use the West Seattle Low Bridge (a.k.a. Spokane St Swing Bridge) to reach West Seattle
    • If traveling to Harbor Island, take the exit toward "Port of Seattle Terminals 5-18/Harbor Island/11th Ave SW"
    • Drivers can also use the SB 99 on-ramp to the West Seattle Bridge throughout this time period

Funding  

The SSV is one of three Seattle bridges that will receive $4.5 million for repairs. The Federal Highway Administration Bridge Improvement Program supplies this money. Thanks to a Bipartisan Infrastructure Law, we can perform these repairs. 
 

Materials

• We will share our outreach materials here when available