Long story short, ``We underestimated the density of materials we have been cutting through and now are replacing with materials that should have been the default configuration.''
Whether the tunnel was the best choice is no longer the question. I favored a suspension bridge from Harbor Island to the 99 connector. Taking down and viaduct and either replacing it or not replacing it would have meant years with no traffic corridor at all, and was the main driver behind the tunnel. The comments I read sound like folks who don't have a lot of experience with the physical world of machinery and big projects. Right now, there are 5 or 6 tunnel projects going on right here in Seattle. The big one for Metro ran into exactly the same sort of problem where they had to lift the head out and repair it. Tunnel completed, on time and near budget. This tunnel will get done, and the execution of the job will be studied for those who go on to build elsewhere. Since the tunnel walls get laid behind the boring machine, there is never a reverse on any big tunneling project. This access hole was in lieu of bringing the machine out in pieces, and is working. I'm glad they tunneled under the viaduct along the waterfront because this wouldn't have been possible if the tunnel had gone more under downtown. Relax folks, and enjoy the show. This is really an amazing project.
Bruce Sherman That's a great explanation. But it does seem this project will be late by about 20 months if there are no more issues (current projection is Fall 2017 instead of December 2015). I guess we'll get a better sense of what the final cost will be once Bertha is running again and makes more progress.
We begin by tying a string to Bertha's tooth. The other end is then tied to the knob of a door. When the time is right we will then slam the door shut extracting the bad tooth. Upon completion of the removal of said tooth we will then place it under Bertha's pillow. Hopefully by morning the tooth fairy will pay a visit and leave $195,000,000.00 to help pay for the procedure.
Colin Gibson Because it was the least practical way of doing it, it was the most expensive and it won't accommodate much of the traffic that heads that way. Makes sense, right? This is Seattle. The least practical is SOP.
The tunnel is in no way impacting (now or in the future) downtown traffic. Brilliant idea. Sink money into a sinking project.I think bringing the sonics would have been a better idea.
Nack Athens If they just rebuilt the viaduct, the view would stay the same as it is now and it would be easier to build, cheaper and it wouldn't cause damage. The machine has only made it 1000 (out of two miles) feet and surounding buildings have sunk up to an inch, streets have cracked and the present viaduct, which has earthquake damage, has sunk up to .5 inches in places. If they keep going with this tunnel idea, chances are very high of disaster. Seattle being what it is, will only rethink what they are doing when a disaster happens. A road will sink, taking a few cars with it, the viaduct will colapse, likely during rush our. They may be able to kill a hundred people with that one. Maybe a building will collapse. Who knows how many people that they can kill with a building collapse. Since so many buildings have sunk up to this point, when the first one goes down, they will condemn the rest in the area. This comes from a state that has a history of collapsing suspension bridges and sinking pontoon bridges. They seem to be hell bent on trying to up their destruction record, maybe taking people with it this time. the project is two years behind schedule now and the boring machine is still broken. they dug an access hole, (undermining the surrounding area even worse) just in front of the cutting head so they could get it out of the hole. The machine had to move forward 20 feet to be accessible. It moved 3 feet and quit. Now what? This is like watching the three stooges but in this case, there's hundreds of them.
What a joke. It's a $4 billion dollar joke on the taxpayers of Washington, with construction companies and real estate moguls laughing all the way to Chase bank. And all this repair because the $80 million machine with no reverse hit a small pipe that WSDOT left in the ground during initial exploratory work. This is not a proud moment in Seattle's history.