West Seattle Bridge can be repaired but SDOT has not yet reached their decision
Wed, 06/17/2020
The second meeting of the West Seattle Bridge Task Force revealed some new information on June 17. First, Matt Donahue, Seattle's primary bridge engineer revealed that hairline cracks continue to form on the bridge, even with no live load. Donahue said, "We can fix the bridge but the question is, should we? A cost benefit analysis on that question will be done by this fall." The decision will come later. If they do, it could open in 2022 but might only offer limited service, meaning fewer lanes.
Crack width and crack slippage are being monitored and if certain thresholds are reached regarding speed of change of amount of change key team members are immediately notified. Donahue said his team and others would call 911 in the event of catastrophic failure but for now that's still not likely.
He said Kraemer North America, contracted to do repairs to the bridge bearing on the east side of the bridge at Pier 18 was in place near the bridge now and working on constructing steel lifting frames that will be suspended under the bridge as work platforms to permit the application of carbon fiber wraps to the exterior of the hollow concrete girders. They will apply the material, which is bonded to the surface with epoxy, to hopefully stop the cracks from propagating further and give the bridge more strength. He did not offer a timeline on that work.
The bridge could potentially return to service if the decision was made to go ahead and complete repairs but that must wait.
They will likely reach a conclusion on repair or replace by this summer. If they choose to repair it they will do the carbon fiber wrapping, complete the work on the Pier 18 bearing, move to the shoring and design work. Along the way, working on parallel tracks they would begin preliminary design work for a replacement including type, size and location.Donahue indicated that the tunnel, proposed by retired civil engineer Bob Ortblad was being given serious consideration as one of the options. Then they would move ahead with repairs with the earliest possible opening date being sometime in 2022. If they get repairs complete the replacement bridge would begin work in approximately 2032 as the repaired bridge reaches the end of its repair status.
If they choose to replace it instead all the stabilization, strengthening and shoring would still take place, but then they could begin a controlled demolition process, followed by construction, resulting in an opening date of betweeen 2024 and 2026. That bridge might have a 50 to 75 year lifespan, depending on type, size and location.
No mention was made of the potential inclusion of light rail.
SDOT's Goal- Reconnect West Seattle
Heather Marx, Director of Downtown Mobility for SDOT said that the vision is to get similar levels of travel across the Duwamish as before the bridge failed. She said that to achieve that goal it has to be a community led process. She noted that the bridge closure created a situation that can't be solved with just detours or service changes. "At the beginning of 2020, there were 21 vehicle travel lanes across the Duwamish but now there are only 12 and most of those are concentrated at the south end of the peninsula. In 2019 82% of the trips across the Duwamish were people in cars, followed by transit at 17%, then water tax at 1% and then bikes also at 1%.
Somehow we need to solve the lost 53% of trips that trips across the West Seattle Bridge represented.
She said that individually each of us is going to have to take part in that solution.
Marx pointed out that the increase in vehicle volumes for West Marginal Way SW at hte Duwamish River Trail went up by 154% and the increase at Highland Park Way SW at West Marginal Way SW was up by 108%. Other routes were single digit increases.
As they consider how to address the impacts of heavier traffic Marx and SDOT were careful to point out that this has race, environmental and social justice implications. Traffic means more air pollution, can affect public safety, and the economics of the Duwamish Valley.
She made note of different modes of transportation including bikes, buses, ferries, business shuttle vans, van and carpools and the water taxi.
Given those implications she spoke about a community led effort to get West Seattle and those traveling across it to points east should examine a draft approach to solve these problems.
SDOT will collect all the potential ideas for traffic mitigation from the community then create individual neighborhood proposals concentrating on Highland Park, and Roxhill, Georgetown, South Park and SODO. These plans will not exceed $100,000 and take less than 12 months to build.
Following that they will go through a neighborhood priortization process and the final plans will be reviewed by the West Seattle Community Task Force and the final working plans, based on affordability will then be the subject of community meetings followed by actions and timelines.
The next meeting for the Task Force will take place on Wednesday at Noon and will cover access to the low bridge. The link to that public WebEx meeting will be announced early next week.
Comments
We live by PCC in admiral…
We live by PCC in admiral. We went to Costco on 4th ave today. What would have been a 30 minute round trip took Driving time over 2 hours round trip not including shopping time. We started at noon, so it wasn’t rush hour. Many folks are still working from home. When the quarantine is over, it will be worse. We need the bridge fixed now, and work on a tunnel simultaneously!
Please repair the bridge and…
Please repair the bridge and use the 10 year life span to get the replacement accomplished.
2 years to make repairs?…
2 years to make repairs? That's ridiculous. Isn't this a city full of engineers? Folks need access to Seattle NOW, not in two years. Asking folks to commute via water taxi , bike rides and telework is ridiculous and still doesn't solve the problem! My husband is undergoing treatment at the SCCA and it now takes us over an hour to get there and over an hour to get back. This trip used to take 20 minutes. With traffic, maybe 25. SDOT needs to fix the bridge NOW and come up with a solution that isn't 10 years down the road!
Fix the bridge! We dont have time to replace!