Bridge Seismic Program

What is the Bridge Seismic program? 

Earthquakes could have a major impact on Seattle's bridges. To address this risk, the City of Seattle established a bridge seismic program to assess how vulnerable the City's bridges were to earthquakes and reinforce bridges to withstand the potential impacts of an earthquake.  

As part of the Levy to Move Seattle, we committed to seismically reinforcing 16 vulnerable bridges.  

What is a Bridge Seismic Retrofit? 

In a seismic retrofitting project, SDOT modifies a bridge’s components and reduces its vulnerability to earthquakes. We do not change the current use and operation of the bridges.  

Typical modifications include: 

  1. Repairing cracks and damaged concrete
  2. Installing concrete blocks and supportive shells for the bridge's columns and crossbeams
  3. Strengthening the existing arch with a concrete infill wall
  4. Installing carbon fiber wrapping to the bridge's crossbeams, columns, and arches
  5. Replacing the expansion joints at both ends of the bridge  

Graphic showing possible modifications SDOT can make during a bridge seismic improvement.

Possible modifications SDOT can make during a bridge seismic improvement. 

Citywide BSR Map showing all current and past projects

A bridge seismic retrofit is a critical process for ensuring the safety and resilience of our city's infrastructure. With Seattle being located in an earthquake-prone region, it is necessary to take proactive measures to protect our bridges from potential damage.

During a seismic retrofit, SDOT (Seattle Department of Transportation) makes modifications to a bridge's components in order to reduce its vulnerability to earthquakes. It is important to note that these modifications do not change the current use or operation of the bridges.

Some typical modifications include repairing any existing cracks and damaged concrete, installing concrete blocks and supportive shells for the bridge's columns and crossbeams, strengthening the existing arch with a concrete infill wall, and using carbon fiber wrapping on key areas such as crossbeams, columns

Bridge Seismic Retrofit Locations

To learn more about an individual project, click on the project name below to visit its project webpage:

Active Seismic Retrofit Projects: 

Completed Seismic Retrofit Projects: 


Fact Sheet (December 2023) 


From 2016 through 2024, the Bridge Seismic Program is funded by $67 million in Levy to Move Seattle dollars, as well as an additional $14 million of other funds. 


If you need this information translated, please call (206) 771-0481.  

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Odeeffannoon kun akka siif (206) 771-0481

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당신이 번역이 정보를 필요로하는 경우에, (206) 771-0481 ? 전화 해주십시오.  


Greg Spotts, Director
Address: 700 5th Ave, Suite 3800, Seattle, WA, 98104
Mailing Address: PO Box 34996, Seattle, WA, 98124-4996
Phone: (206) 684-7623

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The Seattle Department of Transportation (SDOT) is on a mission to deliver a transportation system that provides safe and affordable access to places and opportunities for everyone as we work to achieve our vision of Seattle as a thriving, equitable community powered by dependable transportation.