West Seattle Bridge at sunset. Photo Credit: Madison Linkenmeyer Every Monday, we’re posting a blog to keep you informed about our progress to stabilize the bridge, our efforts to address traffic and mobility, and other items related to the West Seattle High-Rise Bridge closure.
In this week’s update:
- High-Rise Bridge Stabilization Update
- Paving Work on 16th Ave SW & Tree Trimming on West Marginal Way
- Upcoming Community Outreach
High-Rise Bridge Stabilization Update
This past week, we reached two significant construction milestones to stabilize the High-Rise Bridge:
- We released the restrained lateral bearings at Pier 18. (Read more on our blog.) The lateral bearings, which transfer the load from the bridge superstructure to the bridge pier, were compressed and bulging, locking together these two critical parts of the bridge that are normally independent of each other. The bearing was creating additional pressure on the surrounding area and affecting the bridge as a whole. You can learn more by watching the YouTube video.
- We also continued the stressing of the post-tensioning system, which will reinforce the strength of the bridge’s concrete superstructure.
Pier 18 Photo Gallery
Crews prepare to “release” the compressed bearings on Pier 18. 
The line saw set up to precision-demolish the concrete surrounding the bearings.
Upcoming Work
This coming week, the contractor is planning to:
- Begin the final phase of carbon fiber reinforced polymer (CFRP) wrap to strengthen the exterior bridge girders, which support the bridge deck
- Continue to wire-saw the concrete released from Pier 18 into smaller pieces and remove the concrete blocks
Next, Kraemer North America will do other stabilization work, including applying the final layers of CFRP wrap to the bridge girders and rebuilding the lateral bearing at Pier 18. Once all stabilization work has been finished, we will lower the work platforms onto barges and remove other temporary work structures.
We expect to complete stabilization work by the end of this year. This work includes wrapping weakened areas of the bridge, adding post-tensioning inside the girders, and injecting epoxy into cracks wider than 0.3 mm. The epoxy injections don’t stabilize the bridge; they help prevent further deterioration by protecting the post-tensioning steel inside from corrosion. Monitoring and inspection activities will continue after stabilization work is complete, whether the bridge is repaired or replaced.
Construction Impacts
Kraemer North America, our contractor for the stabilization work, is working Monday through Saturday from 6 AM to 4:30 PM every week to stabilize the bridge.
While the majority of the traveling public will see little to no traffic impacts during Pier 18 work, there may be lane reductions on Klickitat Ave SW and SW Klickitat Way on the west and south sides of Harbor Island. Please obey the traffic control signs and devices, and do not attempt to move them. Our teams are coordinating closely with the Port of Seattle to mitigate traffic impacts.
During daily work, you will see some crews working on top of and under the bridge, as well as scaffolding and crews working on platforms suspended under the bridge. You may also see large equipment and vehicles delivering, moving, and storing materials. There is work taking place inside the bridge that you will not be able to see. That work includes monitoring cracks and installing the additional post-tensioning strands.
Past Work
Stabilizing the High-Rise Bridge is necessary to preserve public safety and the integrity of the bridge so that all options remain on the table with the approaching repair or replace decision. Stabilization puts us on the right path if repair is determined to be the best option and helps prevent further crack growth. Stabilization is also necessary for safe demolition if we choose to replace the bridge.
Since we closed the bridge in March, we have:
- Installed an intelligent monitoring system to better understand what type of stabilization and repairs would be needed and to monitor the bridge during this work.
- Designed and started to install stabilization measures, including safety upgrades on Pier 18 and the post-tensioning system
- Built and hoisted custom work platforms.
- Completed the first phase of carbon fiber wrapping.
- Completed the cost-benefit analysis (CBA) that will help inform the decision to repair or replace the bridge.
Paving Work on 16th Ave SW & Tree Trimming on West Marginal Way
This past weekend, crews began paving work on 16th Ave SW near the north entrance to South Seattle Community College. Paving is weather dependent, and paving on 16th Ave SW is currently planned to continue this weekend.
Our Urban Forestry crews also trimmed trees in the 6000 block of West Marginal Way SW.
Upcoming Community Outreach
Our outreach team is continuously connecting with the community to gather your input and hear about day-to-day experiences in West Seattle and the Duwamish Valley. Upcoming events include:
- Tuesday, Nov. 10: Maritime Town Hall meeting
- Tuesday, Nov. 10: South Park Neighborhood Association meeting
- Monday, Nov. 16: Georgetown Community Council meeting