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West Seattle Bridge milestone: Repair remains on track as we begin search for contractor for final phase of construction

West Seattle High Rise Bridge viewed from below.


  • We have reached the preliminary design milestone for the West Seattle High-Rise Bridge (high bridge) this week.  
  • This important step allows us to begin the selection process for a private contractor to make improvements to the high bridge and Spokane St Swing Bridge (low bridge). 
  • We’ll select the most qualified contractor and bring them on board early in the design process to reduce unexpected issues when construction starts.   
  • While we focus on reopening the high bridge as soon as possible, we’re doing preventative maintenance on the low bridge to make sure it stays open and usable.  
  • The preliminary design for both bridges calls for using tried-and-true construction methods, including post-tensioning and carbon-fiber wrapping. We used these methods in phase 1 stabilization of the high bridge to strengthen it and reduce further cracking.  

We’re moving from emergency stabilization to full rehabilitation with an accelerated design process. We’ve now reached preliminary design—a huge milestone! 

As you may remember, we’ve completed phase 1 stabilization of the bridge. We are now monitoring how the bridge is responding to stabilization during seasonal temperature changes, particularly from colder to warmer weather. Now, we’ve reached the preliminary design milestone. 

Reaching preliminary design allows us to begin the selection process for a private contractor to complete rehabilitation of the high and low bridges. This contractor will begin final repairs this year and work to reopen the bridge in 2022. 

These repairs, which use tried-and-true methods that stabilized the bridge in 2020, are part of a comprehensive plan that provides the highest degree of certainty for a safe and rapid restoration of travel with the lowest level of impact to communities in and around the Duwamish Valley, the city, region, and state. 

Reaching this milestone also allows us to provide more specific cost estimates and continue diligent work to secure all necessary funding. For both the high and low bridge rehabilitation, total estimated costs are approximately $72 million ($58 million for the high bridge and $14 million for the low bridge). Standard practice for bridge rehabilitation projects includes using overall cost estimates at this preliminary design milestone as a baseline.  

We advertised today a Request for Qualifications and Project Approach to the private sector consultant community, initiating the process to bring the contractor on board to finish the design and construction of the rehabilitation measures on the bridges.  

This method expedites the process through efficient collaboration and allows us to restore travel across the high bridge as quickly as possible.  

Using this method – considered an “alternative delivery” method – we engage the construction contractor earlier in the project timeline; in this case, the contractor is coming on early in the design phase. Traditionally, a construction contractor is selected once the design is complete. When the designer and contractor work collaboratively, there are more ways to ensure schedule predictability. For example, the construction contractor can provide input while the design contractor finalizes the design, and the designer can provide input on the construction contractor’s means and methods to building the work — such as where work platforms will be raised and attached to the bridge.   

The selection process invites contractor teams to show how their experience and qualifications make them the best fit for the work. Shortlisted firms will be interviewed later this spring. 

We are also petitioning the United States Department of Transportation (USDOT) to allow the use of the city’s Priority Hire Program on this federally funded project. If approved, the city will be able to create local jobs and put more money back into underserved communities near the bridge and around the county. 

We remain committed to the federal and state Disadvantaged Business Enterprise Program (DBE) and the city Women and Minority Owned Businesses (WMBE) Program to support women- and BIPOC-owned businesses in these government contracting opportunities . Through the WMBE program, we make it a priority to employ BIPOC and women-owned businesses for at least 30% of consulting and 19% of purchasing needs. The rehabilitation projects will include a DBE goal, which we will set later in the design process in coordination with funding partners. 

“Our work to reopen the bridge is on track, and we’ve made great progress to date. Simultaneously, we are continuing to implement solutions for impacted communities – including traffic mitigation, paving, detour signage, and installing safer walkways and bike lanes. I am proud of the work of our teams across the department as we continue to work with urgency to restore the vitally important connection the bridge provides to our region.” 

SDOT Director Sam Zimbabwe

Coupled with Mayor Jenny Durkan’s rapid decision to initiate stabilization repairs in March 2020 and the work we have been completing on, under, inside, and around the bridge since last spring, this means that not a moment of forward progress is lost. 

Against the backdrop of combined challenges brought on by COVID-19, we have kept the vital West Seattle High Rise Bridge Safety Program on schedule. While the advertisement and selection process is a major part of many of our construction projects, the contract method we are using for bridge rehabilitation is helping to keep the project moving as predictably as possible.  

This milestone follows other important efforts in 2021, including planning and implementing improvements to Reconnect West Seattle, working with communities to plan projects that calm traffic and improve neighborhood livability through Home Zone plans, and more — all while working hand in hand with regional and federal transportation partners.  

“The bridge closure has had so many impacts on the residents and businesses of West Seattle, Georgetown and South Park. We’re keeping pace with our aggressive schedule and taking another major step toward reopening the West Seattle High-Bridge. SDOT and our workers continue to make progress in the pandemic to successfully achieve a very significant milestone on schedule. ”   

Mayor Jenny Durkan

On the high bridge, rehabilitation is currently designed to use many of the same methods that we used last year during stabilization—methods shown to help strengthen the bridge and reduce further cracking. 

A graphic side view of the West Seattle High-Rise Bridge showing approximate locations of completed phase 1 stabilization efforts, including post-tensioning, carbon-fiber wrapping, and monitoring equipment.
A graphic side view of the West Seattle High-Rise Bridge showing approximate locations of planned phase 2 rehabilitation efforts, including new post-tensioning and new carbon-fiber wrapping.

In 2020, we used stabilization methods including epoxy crack filling, carbon-fiber wrapping, and post-tensioning. We also “released” the lateral bearings at the Pier 18 column, which were compressed and bulging, locking together two critical parts of the bridge that are normally independent of each other. Our monitoring has showed that during the recent February snow, the high bridge stabilization measures performed as expected with a foot of snow across the bridge adding weight. 

Currently, the preliminary design for phase 2 rehabilitation on the high bridge includes additional post-tensioning cable and anchor systems and additional carbon-fiber wrapping across the central and side spans. By definition, however, the preliminary design milestone is just that, and the design plans will continue to be refined as the contractor comes on board and the project moves toward final design. 

You might have also noticed that we’re adding more post-tensioning to the high bridge’s center span, in addition to post-tensioning in new areas, between bridge columns Pier 15 and Pier 16 and between Pier 17 and Pier 18.  

During phase 1 stabilization, our teams intentionally added enough post-tensioning to stabilize the bridge until we had a clear path forward on whether we were going to rehabilitate or replace the high bridge. This next phase takes us to the finish line so the bridge can be traveled on again.  

While we focus on getting the high bridge reopened as soon as possible, we’re also conducting preventive maintenance on the low bridge.  

A graphic side view of the Spokane St Swing Bridge showing approximate locations for planned carbon-fiber wrapping.

We have no reason to think that the low bridge is at any imminent risk of being taken out of service, but because it now plays such an important role as a link between West Seattle and the rest of the city, we have developed a forward-thinking plan to strengthen it further. The impacts of preparing for and conducting repairs now outweigh the impacts to the community and maritime/industrial businesses if emergency repairs and maintenance were needed and unexpectedly closed the bridge.  

On the low bridge, we’ll inject strong epoxy into any existing cracks and add carbon-fiber wrapping in several locations on both the interior and exterior concrete surfaces of the swing spans. We’ll also conduct other improvement projects, including the Low Bridge Controls Project to upgrade and reroute the control system that enables the bridge to swing open, as well as the Lift Cylinder Project to refurbish the hydraulic cylinders that help the bridge to swing open. 

We’re combining rehabilitation efforts on both bridges into one contract, allowing for improved efficiency in both construction coordination and scheduling, and minimizing impacts to the community. We aim to have another update on the rehabilitation schedule this summer as we move through the design phase.  

Learn more about our tried-and-true stabilization methods on our High Bridge Rehabilitation and Low Bridge Projects webpages.  

Our teams are also working continuously to ensure that we are making smart use of our contractor team after they are brought on board.  

We’ll continue to look at opportunities to make improvements to the Pier 18 foundation and identify other possible roadway and paving improvements along the West Seattle Bridge corridor.  

We know many of you  are eager to see things moving on the bridges; we are too!  

Rest assured that we’re doing everything we can to accelerate the design process to complete the high bridge rehabilitation work as efficiently as possible, while keeping safety as our top priority. As we reach a further stage in design and select a contractor we’ll be able to share more updates about when you can expect to see construction teams at work on both bridges.  

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