99 TUNNEL: Southbound closure added next weekend for repairs

(WSDOT photo, February 14)

The weekly SDOT lookahead (PDF), which often brings first word of key WSDOT closures too, arrived with news of an added Highway 99 tunnel closure described as being for “repairs,” 10 pm next Friday (February 28) to 8 am next Saturday (February 29). We asked WSDOT spokesperson Laura Newborn if the repairs are related to the water leak from the southbound tunnel’s ceiling. She said yes, elaborating;

The purpose of the closure purpose is two-fold.

1. For the tunnel contractor to repair and reseal a small grout-port where water is leaking (the tunnel is under warranty).

2. To complete regularly scheduled tunnel maintenance from Friday, Feb. 14 as crews spent maintenance time creating a temporary repair for the water leak.

We want to emphasize this is considered a minor leak with a straightforward repair plan. The tunnel remains very safe for driving.

The repairs involve re-grouting the area near a grout port and resealing the grout port. During construction, these types of ports were used to add grout to the area between the ground and the outside of the tunnel wall.

Again, that’s next Friday night, NOT tonight. The NB tunnel, meantime, has a regular maintenance closure March 13 (10 pm)-14 (8 am).

12 Replies to "99 TUNNEL: Southbound closure added next weekend for repairs"

  • West Seattle Hipster February 21, 2020 (3:17 pm)

    Leak repairs aside, it would be interesting to know why the tunnel needs to close so often for maintenance work.  I expected occasional closures the last 2 decades of the viaduct’s life, but this tunnel is relatively new.  Is this a common occurrence with similar tunnels?

    • KBear February 21, 2020 (8:18 pm)

      Hipster, if you consider how long the tunnel is and how many systems are involved with its operation, I don’t think it’s any surprise that they have to close it down regularly for maintenance. It’s not an indication of failure, but  they can’t work on it with traffic running through. 

  • dsa February 21, 2020 (4:06 pm)

    I wonder if they have a way to measure water pressure.  I would drill an easily sealed pilot hole first if they are exploring into the unknown.

  • flimflam February 21, 2020 (6:01 pm)

    hey, its been open for MONTHS now – repairs are inevitable!! lol.

  • steve February 21, 2020 (10:09 pm)

    we’re all gonna die!!!

    • WSB February 21, 2020 (10:15 pm)

      Well, yes, of course we are.

  • Joey February 21, 2020 (10:32 pm)

    Leaking water from a pipe or from the Sound……..? This isn’t exactly instilling confidence in the engineering.

    • WSB February 21, 2020 (11:08 pm)

      Seems to be a common problem in underground tunnels. Quick search brings up many citation. The tunnel doesn’t go under the bay, though.

  • Jim P. February 22, 2020 (11:26 am)

    ” For the tunnel contractor to repair and reseal a small grout-port where water is leaking (the tunnel is under warranty).”

    I hope they kept the receipt and the shipping box in case they have to return it.

    Problem is, as I see it is you need to fix a leak from the outside, not on the inside.

    If your boat is leaking, a patch on the inside won’t do diddly in the long run.

    I keep coming back to this thing only being two lanes each way. I seem to recall the viaduct was a wee bit larger with more capacity and yet seriously overcrowded and the city has massively grown since this plan was put together.

    • dsa February 22, 2020 (1:39 pm)

      Jim P I totally agree with your last paragraph.  I do want to point out though that it appears to me that this is an attempt to make the leak repair to the outside of the rings via a currently sealed small access hole.  And it should work.

  • Bob Forrest February 23, 2020 (4:27 am)

    The viaduct was very simple in concept and execution, built and maintained with proven, age-old technology.  The Chunnel (Chumptunnel) is one complex, untested system layered upon others, layered upon others.  It is predictably going to be a thorn in Seattle’s side, forever.

  • John February 23, 2020 (9:21 am)

    I am relieved when  enjoying  the drive through the tunnel,  that none of these commenters were involved in its design and construction.

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