KENT, Wash. — The opening of several Sound Transit light rail extension projects will be delayed a several months to more than a year because of various construction issues, the board for the Seattle-area agency was told last week.
The Seattle Times reports the East Link project, a line from downtown to Bellevue and Redmond, will open at least a year after its projected July 2023 date because 4 miles of concrete supports must be reinforced or rebuilt between Seattle and Mercer Island. The news site MyNorthwest.com reports that track is having to be removed on those 4 miles on either side of the floating bridge across Lake Washington, while KING-TV reports there are issues with precast blocks and fastener bolt inserts on the bridge itself.
Another section of that project, reaching further into Redmond, is now projected to be completed four to five months beyond the original December 2024 target, mostly because of delays resulting from a four-month strike by concrete-truck drives.
The concrete-truck strike is also responsible for a four-to-six-month delay on the northern extension from Northgate to Lynnwood, deputy CEO Kimberly Farley told the board. That addition had been expected to open in July 2024.
And the Federal Way extension between Angle Lake and Federal Way will require different underground supports after a July landslide in Kent showed the ground was more unstable than had previously been believed. That will push back completion of that segment from late 2024 into 2025.
Negotiations with construction companies over the delays are in progress, and no estimate of the costs resulting from the delays has been released.
— Updated at 7:15 a.m. CDT on Aug. 23 with additional details on East Link problems.
Typical Sound Transit “hurry up and wait”, but to be fair, there are some extenuating circumstances related to the concrete-driver strike in the Seattle region delaying concrete deliveries to the Lynnwood LINK project (and thus delaying it).
The section of ST Federal Way LINK ROW does indeed have some soil liquification issues as noted by Mr. Jones above. HOWEVER, it would appear that, yes, not enough soil (core) samples were made to discover this issue. Perhaps a source of litigation between Sound Transit and its contractor.
The I-90 “Floating Bridge” and the Eastlink light rail line that is being built on it, was always going to be a complex engineering challenge, unprecedented in fact (first “floating” light rail bridge structure in the world!) and will likely have more engineering challenges before it is ready for operation (in 2024?).
But Sound Transit and the ‘experts’ promised everyone that this could be done. We will see …..
Unfortunately Sound Transit does not have a good track-record of delivering its rail (light-rail and commuter rail) projects “on-time” and “on-budget” thus far ….
The landslide in Kent showed that the Federal way construction piles are not sufficient to support the track. It appears that area is subject to liquidfaction . That would mean that under an earthquake situation that support of track might fail. What appears to have happen is that not enough coring samples were taken to find these liqifaction zones. Preliminary engineering mistakes probably due to the coring work contract did not call for enough samples?
Solution? Cannot even specuate until new engineering work is completed to determine what mitigation will be needed.
At least some of the concrete supports in question are on the I-90 floating bridge over Lake Washington. Ever since this line was started, I’ve expected that there would be issues since it is all ‘cutting edge’ technology to have trains cross a floating bridge that has quite a bit of movement. This might only be the first problem, there is a good chance of more to come.
Four miles of concrete supports need to be reinforced or rebuilt?
Could we have more detail please? What was the mode of failure and how did it happen?
Yes, early failures can – and do – occur in concrete structures. Rarely. This one seems a little much.
You could actually click through and read the article. It’s a thought.
The upshot is that the construction work was of poor quality and the contractor has to go back and fix it.