Seattle is a truly fabulous city. It may be gone soon if they keep this up. Visit while you can!
Apparently, earthquakes have been damaging the elevated viaduct, and they decided they had to replace it. So...a tunnel! Somehow going underground to avoid earthquake damage doesn't seem all that logical to me. But, what do I know? Certainly, brilliant engineers and planners are on the case who know all about this stuff.
However....there have been problems. Lots of problems.
Drilling began July 30, 2013. On December 6 of that same year, drilling stopped. After a month of investigation, it was announced that the blades of Bertha, the massive drilling machine, were damaged after hitting a steel pipe "left over from a previous 2002 drilling project" that assessed groundwater conditions.
Lesson learned, we hope.
In February 2014, when they finally got her fixed and ready to drill again, they discovered Bertha was overheating. It appeared a seal in the front of her was broken. The Wikipedia entry for Bertha notes that rather than go through the lengthy process of taking the machine apart from the rear, it was decided to lift it from its location underground up to street level to replace the seal.
(FYI, Bertha was not made in the USA. Japan. Assembled in Seattle.)
Here I have to say, you may have noticed a problem with my reporting. I admit it. I don't know how they replaced blades without bringing Bertha up to the ground level but decided it was too time-consuming to replace a seal that way. Or why there wasn't a check of her seals when they took care of the blades. Could we just skip that and move on, though? This story is long enough as is, and I've done all the research I can take for now.
So...
In actuality, when they went in for the seal repair, they discovered damaged drive gears as well. (Yes, apparently not discovered when they replaced blades.)
At any rate, Bertha was finally lowered back into the ground on August 24, 2015, but for some reason, digging was not resumed until December.
Apparently, fortunately for some, and not so much for others, some official folks were checking out related issues not involving the repair of Bertha herself, and so it was discovered that the ground under Bertha had settled an inch. And settled unevenly.
Oh yes, indeed, costs on the project are climbing steeply. And the insurance companies have been weaseling out of paying for machine repairs, as you know they would, claiming Bertha was not built to stand up to the use she's getting."A whole block just went down an inch," said Todd Trepanier, the administrator of the project for the State Department of Transportation, at Monday's City Council hearing. "We don't like an inch."
[...]
The New York Times reports that the settling has affected about 30 businesses in the Pioneer Square area above the tunnel-borer's current location, with some reporting new cracks in their basements and foundations.
Popular Mechanics
Trying to get to the main problematic issues of the project, I went straight to Wikipedia - a summary, if not best-practice research tool - to get started on this post. Apparently, people there have simply given up staying current with the "progress".
And done. March 2015 was some time ago. What happened?Boring of the tunnel began on July 30, 2013, with the roadway scheduled to open in 2015.[7] Tunneling stopped on December 6, 2013, after the boring machine struck a pipe, which obstructed its path. Boring resumed briefly on January 28-29, 2014, stopping again due to damage to the seal system which protects the machine's main bearing [2]. Work is expected to resume by March 2015 [3].
Wikipedia
We must go over to the Wikipedia entry for Bertha herself where people seem to be keeping up.
Or, we can "follow Bertha" at the Washington DOT website.
As noted earlier, drilling began July 30, 2013. It was originally estimated (by some very optimistic people) the 1.7 mile-long tunnel would be completed and open to traffic December 2015. What's the over/under now, I wonder, for when (if) this thing will be completed? The January 13, 2016, Seattle Times reported April 2018 as the date Seattle Tunnel Partners have projected for the tunnel to be open to traffic. The Washington DOT site posts the last estimate (2015) from STP as January 2017 to finish drilling, with nothing mentioned about opening to traffic.
Take another look at that map. After 2-1/2 years, they're still in Zone 1. I'm feeling a little skeptical about that January 2017 date.
Of course, Zones 2-10 could be really smooth sailing. Er...drilling.
Apart from all the issues in the early stages, and now that Bertha has had her numerous repairs, why are they still in Zone 1?
Well....
It's not told whether the reporters were, in fact, assured.Tunneling on the project to replace the Alaskan Way Viaduct came to a stop Tuesday [January 12, 2016] after damage to the pier where crews load dirt from the project onto barges left no options for getting rid of the excavated material, officials said Wednesday.
But before mining stopped completely, a 35-foot-wide sinkhole started opening up Tuesday night [over ground that had already been tunneled].
[...]
[Chris Dixon, project manager for Seattle Tunnel Partners] assured reporters that the 15-foot-deep sinkhole, which opened up just to the west of the viaduct and not far out of the access pit, was not a dire incident and would not be an issue going forward.
Seattle PI
Sure. I believe that. [By the way, it looks like sinkholes in Seattle are not all that uncommon.]"The sinkhole is an unfortunate event, but isn't something that is unique or something that wasn't anticipated," Dixon said.
[...]
The top of the tunnel is about 60 feet deep where the sinkhole opened up, but as Bertha digs deeper, the risk of future sinkholes will be minimal, if anything at all, Dixon said.
But, it gets better.
That would probably be a good idea.The cause of the sinkhole wasn't made exactly clear by Dixon, but he did indicate that workers running the machine were paying less attention to the soil than the machine.
[...]
Workers were focused on how the world's largest tunnel-boring machine was working and were relying more on "theoretical" measurements of dirt being removed, a practice that will change now, Dixon said.
Washington DOT officials have a slightly different take on the sinkhole issue.
Well, thank goodness, eh? Only one more block of downtown Seattle businesses to worry about their foundations.State DOT officials say this is the only area where Bertha will be digging through loose soil. For the first time in her journey, she's digging through soil that hasn't been strengthened with concrete.
Some of the soil along King Street is glacial till, which is dense and good for tunneling. But a layer near the surface is loose fill material, dumped by Seattle's early settlers.
The fill includes loose soil, sawdust and timber piles that - if disturbed during tunneling - can create voids above the machine.
DOT officials say more sink holes are possible, but only for another block north to Jackson Street.
KOMO News
(Why they didn't reinforce this drill area with concrete, I do not know. Suffice to say they did not deem it necessary - or perhaps feasible. Or perhaps, what the heck? Reinforcement didn't stop the ground from settling anyway.)
And still, it gets better.
Gee, I wonder if that was "something that is unique" or something that couldn't be "anticipated."Meanwhile, damage to one of three barges that hauls dirt from the project to a pit in Port Ludlow, and damage to the pier where those barges dock, has mining halted for at least a couple of days.
[...]
Mining can only resume once there is somewhere to put the dirt.
[...]
The barge and pier damage happened after a barge being loaded with dirt started leaning to one side. For fear of damaging the conveyor that brings the dirt from the tunnel to the dock, crews set the barge adrift, and it eventually hit the nearby Pier 48 and Terminal 46, damaging both barge and dock in the process.
Seattle PI
Please don't destroy Seattle.
...but hey, do what you want...you will anyway.
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