SDOT: High-Rise Bridge stabilization update
Fri, 08/28/2020
information from Seattle Department of Transportation
Since the closure of the West Seattle High-Rise Bridge, SDOT has worked to simultaneously advance all efforts needed to expeditiously pursue both a repair or replace scenario. By advancing both pathways at once, not a moment has been lost while the careful and thorough assessment is done to understand which avenue – repair or replace – is best over the long term. Once that pivot does occur this October, through a decision aided by the completion of a comprehensive cost-benefit analysis, we will not be starting from scratch. We will be standing on a firm foundation of progress, no matter the direction we go.
Today, and every Friday going forward, we want to provide you with a detailed update about the work we’re doing on the bridge. These efforts are necessary to maintain public safety, but have the double and efficient bonus of advancing core elements of the repair work, should we move in that direction.
Kraemer North America, our contractor for the stabilization work, is on the bridge every Monday through Saturday from 6 AM to 4:30 PM to stabilize the West Seattle High-Rise Bridge. The stabilization work, which includes wrapping weakened areas of the bridge in carbon fiber, adding post-tensioning inside the girders, and epoxy injecting cracks wider than 0.3mm, is expected to continue at a safe but expedited pace over the course of the next several months.
Next week, the contractor is planning to:
- Continue to inspect cracks
- Fill cracks with epoxy
- Place carbon fiber wrap around recently filled cracks
- Begin to install the post tensioning system
During this work, you will see some crews working on top and underneath the bridge. You will also see scaffolding and crews working on platforms suspended under the bridge. There is additional work taking place inside the bridge – including monitoring cracks and preparing for the installation of the additional post-tensioning strands – that you will not be able to see. We do not anticipate any additional traffic impacts from the West Seattle High-Rise Bridge construction work over the next couple weeks.
Small “syringes” are placed into affected areas and used to channel epoxy into the cracks.
Upcoming Work
Over the next few months, the contractor will continue the stabilization work listed above and will also work to “release” the restrained bearing at Pier 18. There may be traffic impacts associated with the Pier 18 work.
This fall, we will make the final determination as to whether we will move forward with repairing the current bridge or replacing it with a new structure. With our replacement consultant HNTB on board, we are ready to pivot to designing the demolition and replacement structure, should it be determined that it’s in the public’s best interest to replace rather than repair the bridge.
Past Work
Crews have been working hard since SDOT closed the bridge:
- 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 begun to install stabilization measures.
- Built and hoisted custom work platforms.
- Begun the cost-benefit analysis (CBA) that will help inform the decision to repair or replace the bridge.
Work on the ground: what we've done so far to address traffic impacts
Since March, we have implemented 175 changes to support communities affected by the West Seattle Bridge closure.
At the 16th Ave SW and SW Holden St intersection, we installed new turn pockets so drivers can make protected left turns to go east and west on SW Holden St.
During the closure, we’re working to keep people moving, lessen traffic impacts to the best of our ability, and preserve/enhance public safety.
We know that no level of traffic mitigation can overcome the 100,000+ travelers displaced across West Seattle, Duwamish Valley, and all of Seattle by the closure of the High-Rise Bridge. But to the greatest extent of our ability, we’re working diligently to mitigate the impacts and above all else, to maintain public safety for you.
Every day since the closure, our teams have been actively listening to the community and taking action in and around the peninsula to keep you safe.
In our latest blog, we spotlight some of the important work (from the 175+ projects both big and small completed since March) to support those who are affected by the closure.
The results of the recent Reconnect West Seattle community survey (BTW, thanks so much to those who took the survey!), helped us identify and begin implementing some of our biggest safety, mobility, and traffic calming improvements to date. Survey responses were valuable in helping guide our ongoing dialogue with the community and increasing our understanding of each neighborhood’s unique needs.
Since May, when we shared the completion of over 80 delivered projects to mitigate traffic, we’ve implemented over 95 new projects. These include adding pedestrian-first safety upgrades, reducing speed limits, providing ongoing detour route management, and more. Read the full blog post.
Weekend construction and full road closure for Delridge RapidRide H Line
Construction started on the Delridge RapidRide H Line in June 2020 and is expected to continue through 2022.
We will be closing all lanes of Delridge Way SW from SW Barton St to 18th Ave SW beginning tomorrow, August 29, 2020. The work will continue through August 30, 2020 to allow time for Seattle Public Utilities to complete additional work in the area.
During the weekend detour, traffic is detoured to 16th Ave SW.
Please expect:
- Delridge Way SW to be fully closed from SW Barton St to 18th Ave SW
- Local access only to be allowed from SW Henderson St to SW Barton St and 18th Ave to SW Roxbury St
- Restricted turns from side streets onto Delridge Way SW while the closure is in place
- Access to businesses to be maintained at all times
- Traffic to be detoured to 16th Ave SW. Please see this detour map for more information.
How about timing the lights on Michigan to avoid back up to 1st Ave bridge?