Thursday, October 1, 2015

Revisiting the Sea Wall

Today was another in a short string of good days.  That ends tomorrow.  We decided to go downtown and see what was happening with the sea wall replacement.  Apparently it's now running $70M over budget, and is two years behind schedule.
This is the always lovely Elliot Bay.  If you look in the way far off distance you can see the remnants of the morning fog.

It's a big hairy deal of a project.  The original sea wall was made primarily of untreated wood.  If you look on the far side of the photo on the right, in the middle, that may be original timber.  Gribbles are eating the wood.  If the sea wall is lost, it'll take a big chunk of Seattle with it, including the Alaskan Way Viaduct, which you can see in the background on the right.  The other difficulty of the project has been moving all of the utilities along the water front.  Look underneath the reddish metal beam spanning the ditch, those are utilities hanging underneath.

This is a water pipe, suspended from a piece of wood which spans another ditch.  Upper right in the photo is a closed fire station. 

This we did not know until today.  Replacing a sea wall is difficult, because you must keep the water out while doing the work.  Here is an interesting article on the subject.  There is a local company, SoilFreeze,  which has created a 35 foot wall of frozen water.  This greatly lessens the need for de-watering, which causes ground levels to drop, damaging foundations and water lines.

We'd looked at these white blobs on piping and thought they were plastic blobs.  That's ice.

More ice, and a lot of pipe wrap.

We walked back via Pioneer Square and discovered the Milepost 31 museum.  It's a very well done telling of the story of how Seattle got the way it is.  There were glaciers, which extended as far south as Olympia.  There was the Denny re-grade.  Now we are having a deep bore tunnel drilled (maybe).  They had some interesting stuff on the tunnel.  As Bertha moves through the dirt, she also builds the tunnel walls from pre-cast conrete sections.  Berth uses a power vacuum to pick up the sections, each of which weighs 37,500 pounds.

An entire tunnel ring is 10 segments, and can be put in place in 30 minutes (when she's operating, which she's not at the moment.)

An interesting fact from the museum was that a tunnel boring machine was run under the Sagrada Familia, Gaudi's giant church in Barcelona.  They were able to get the tunnel done, and install a high speed train in the tunnel without collapsing the church.  It's an amazing structure. According to the exhibit, some of that expertise is now here.  Tunneling has worked well in Europe, just not so much here.

This is the historic pergola in Pioneer Square.  It's been awhile since it's been hit by a lost truck.

In my humble opinion, the Seattle area has just lost its mind. About 5 years ago, DOT started tolling on 520, which is the northern most bridge over Lake Washington.  People hate tolls.  So they started driving I5 and using I90 instead.  This week on I405, DOT installed tolled HOV lanes. People won't pay it.  So, they're taking surface streets around the top of Lake Washington and totally clogging up those communities, and they're also using I5 instead.  So I5 is just taking it in the head with traffic.  And remember, when the Alaskan Way Viaduct comes down, two lanes of traffic carrying capacity will be lost, and shift to I5.  The new tunnel will be tolled, so that will also move traffic to I5.  Can we spell gridlock?

So, that was our day.  Then we came home to learn about the mass shooting in Oregon.  It's the 41st shooting this year.  There are just no words.

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