High-Rise Bridge Replacement Study

Updated August 9, 2021

What's Happening Now?

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As we continue to work to repair the West Seattle High-Rise Bridge (high bridge), we are continuing to plan for an eventual replacement.

In November 2020, Mayor Durkan made the decision to repair the high bridge and directed SDOT to continue planning for an eventual replacement of the bridge. Once contractors complete the necessary repairs to the existing bridge in mid-2022, we have full confidence it will last for decades.

Because of the complex and lengthy process required to design and plan the eventual replacement, we are continuing with a replacement bridge planning study so that we are ready when the current bridge nears the end of its service life around 2060. At the end of the study, we will better understand the needs of the corridor, including bicycle, pedestrian, and transit options, as well as location opportunities. Having a planning study completed will also allow the City to respond much more quickly in the unlikely event of another emergency.


Historically, the West Seattle High-Rise Bridge is the City's most-used bridge arterial, carrying an average of over 100,000 travelers a day, including 19,000 bus riders. The concrete bridge was built in 1984 and has since been a major route for moving people and goods to and from West Seattle and providing connections with neighboring communities, such as the Duwamish Valley and SODO. In addition, the bridge and surrounding corridor are a critical connection with the Port of Seattle, serving as a path for goods and supporting the regional economy. In March 2020, we closed the high bridge in the interest of public safety. We made this decision based on regular inspections of the bridge, which showed rapidly growing cracks. Since the closure, we've wasted no time, working to repair the high bridge and to plan and build projects across affected neighborhoods that will reduce impacts on local communities. Repairs are now underway, and we expect work to be complete in mid-2022.

Graphic showing bridge repair milestones

What's a bridge planning study?

Our teams conduct bridge planning studies for priority City-managed bridges that are functionally obsolete or structurally deficient. Recent examples are the Magnolia Bridge and Ballard Bridge planning studies. The high bridge was not slated for a study until last year, when rapidly growing cracks caused the emergency closure of the bridge. Now we consider it a priority for long-term replacement and a bridge planning study.

Replacement concept locations being studied

As part of the study, we will focus on 4 replacement concept locations to determine which will best meet the needs of West Seattle and the region. Our team will begin by researching and identifying 4 potential locations within the vicinity of existing bridge, including:  

  • North of the existing high bridge

  • South of the existing high bridge

  • In alignment with the existing high bridge

  • Below in a tunnel

These 4 location concepts were chosen for further study to span the range of practical replacement options, allowing us to explore and compare them to determine how we can best serve West Seattle and the region.

Bridge replacement study area

What's next?

As the team further develops the location alternatives and criteria for evaluating them, we will coordinate closely with adjacent projects, including those being completed by Sound Transit and the Port of Seattle, in order to consider potential impacts and opportunities. We will report out on the initial screening of the long-term replacement concepts in September, and the study findings and recommendations at the end of the year.

Replacement planning study schedule

Bridge replacement planning study schedule

Get involved

We're committed to keeping you informed of our progress on the planning work as it moves forward. At key milestones of the technical feasibility study, we will be sharing our progress with the community.  

We'd like to hear from you.