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West Seattle Bridge: What’s next for bridge repairs and construction before reopening

Crews finished pouring concrete structural components for the new post-tensioning system on May 26. Photo: SDOT

Editor’s Note (June 24, 2022): We added a short 2-minute video to this blog post describing how bridge post-tensioning works. You can view the video below or check in out on our SDOT YouTube videos page.

We expect the West Seattle Bridge to open the week of September 12, 2022, and wanted to share an update on what’s next for bridge repairs.

This blog post details how we’ve adapted to changing construction conditions, what construction work is remaining, and what our next steps are to get the bridge back open as safely and quickly as possible.

What we’ve done to minimize delays during the concrete strike

During the concrete strike, we worked with the contractor to resequence work activities so that progress would continue as we waited for the concrete to be delivered.

During the strike, we modified the schedule by:

  • Changing where epoxy injections and carbon fiber wrapping took place on the bridge
  • Building as many forms (supports used to pour concrete into) as possible before concrete delivery so they were immediately ready for concrete and we could minimize the number of structural pours needed
  • Directing crews to begin major maintenance work, including expansion joint and sign replacement needed to prepare the bridge for reopening

While schedule sequencing changes helped us reduce the strike’s impact, it means we’ve already taken advantage of the schedule efficiencies available to us on a project of this scale. Our contractor has multiple crews working simultaneously, and we’ll continue to seek ways to move our work forward faster if possible, while keeping safety top of mind.

How we’re streamlining the remaining repairs since we’ve received all specialized concrete needed

Many activities are underway at the same time as our “critical path” post-tensioning work:

  • Sign structure replacement (11 total)
  • Bridge deck repair and concrete overlay on the Fauntleroy Expressway (2+ acres of new concrete)
  • Concrete panel replacement on the western approach to the bridge structure (61 panels)
  • Traffic control signs and road striping
  • Illumination and streetlight restoration (14 miles of new wire) in partnership with Seattle City Light
Crews conduct resurfacing along the Fauntleroy Expressway. Heavy equipment is pictured, including a large truck, on a wet and cloudy day.
Major maintenance activities to prepare the bridge for reopening include resurfacing about two acres of the Fauntleroy Expressway. This work involves grinding away a half-inch of the surface and pouring a new concrete overlay. Photo: SDOT

Regardless of how quickly major maintenance activities happen, we still have the most important work left: the bridge post-tensioning system. This work is sequential, so we must complete the job in a specific order.

The steps of the process are:

  1. Let the concrete used for the post-tensioning anchors and supports set and cure (in progress)
  2. Install post-tensioning ducts (in progress) (11,000 feet of ducts)
  3. Complete a pre-tensioning round of epoxy injections and carbon-fiber wrapping (in progress)
  4. Install post-tensioning strands (~46 miles of strands)
  5. Tension the strands
  6. Complete a final round of epoxy injections and carbon-fiber wrapping after tensioning is done
  7. Complete cure time for the carbon-fiber wrapping
  8. Remove work platforms
  9. Load test and inspect the repairs
  10. Restore the bridge deck by closing holes in the bridge deck created for access
  11. Demobilize the site, which means crews remove their equipment (like trailers and tools) from the bridge

For a brief overview of the post-tensioning process, check out this short 2-minute video, below.

West Seattle Bridge repairs post-tensioning overview video. Video credit: SDOT

Our efforts to accelerate remaining work where possible, without compromising safety

When we began construction, we were on an aggressive timeline to complete major construction by summer 2022. The contractor’s initial schedule did not account for a regional concrete strike that delayed major work on the program by approximately two months – the time between when structural concrete was needed for the post-tensioning anchors and deviator blocks and when drivers returned to work. The anchors and deviator blocks are essential structural components for the new system supporting and guiding the post-tensioning strands through the bridge.

The contractor crews are working with urgency and completing the repair procedures without making any compromises and keeping safety at the forefront. They are currently working 10-hour days, six days a week, at capacity and in the interest of worker safety. Our contractor is seeking additional experienced workers, a challenge in this tight labor market.

For the bridge’s post-tensioning system, the concrete must cure for a specific time, so we can’t accelerate the process. Carbon-fiber wrapping also has a specific cure time. These two activities are part of the sequential work that’s essential to restore traffic safely.

We will continue to work with the contractor to find any potential efficiencies as they work through each step in the post-tensioning process and the remaining major maintenance work.

How we’re anticipating and managing future challenges to opening the bridge in September

While our contractor feels confident about the September reopening plan, certain factors are beyond our control.

Those risk factors include bad weather that could affect exterior carbon-fiber wrapping; getting future concrete deliveries for the bridge deck overlay and restoration; and ongoing worker availability.

To manage these risk factors and make it less likely that these issues would alter the schedule, we’re:

  • Prioritizing and scheduling carbon-fiber wrapping during good weather days and tarping these work areas during bad weather days to allow work to continue
  • Prioritizing contractor work on the high bridge over working on the low bridge
  • Continuing close coordination with our concrete supplier to get remaining pours on their schedule as far out as possible
  • Maintaining and scheduling project personnel to the critical path and time-sensitive work items
  • Continuing to require all staff working on the bridge to follow project COVID-prevention protocols
  • Collaborating closely with our agency partners such as King County Metro, the Port of Seattle, Northwest Seaport Alliance, WSDOT, and our partners at the City to develop further mitigation measures for any potential issues as they arise
A worker conducts carbon-fiber wrapping on the West Seattle Bridge as part of the structural repairs that are currently underway. He is wearing a blue hardhat, goggles, and  white work clothing.
After we tension the bridge and compress the structure’s concrete, we will do a final round of epoxy crack injection and carbon-fiber wrapping (seen above) to reinforce the concrete around the new post-tensioning components. Photo: SDOT

Thank you

We hope this information is helpful and appreciate the community’s patience as we continue working on the West Seattle Bridge. We also look forward to providing ongoing updates about this work as it moves forward. Thank you.