Skip to comments.Bertha may be on hold until summer for complicated repairs
Posted on 02/10/2014 10:22:12 PM PST by steve86
Seattle Tunnel Partners says it might repair Berthas damaged seals from the front end, which would require a digging deep hole along the waterfront and could delay the Highway 99 replacement project for months.
Workers might have to dig a hole up to 115 feet deep to reach and repair the damaged drive system of tunnel-boring machine Bertha, contractors now say.
Once the pit was dug, the 630-ton cutter head would be detached and lifted using a crane, supported by wide footings as if on duck feet, so it wouldnt sink into the soft waterfront soils.
Chris Dixon, director for Seattle Tunnel Partners (STP), said Monday his team is weighing four or five options for a front-end mission, and coordinating the use of waterfront surface space with the citys nearby Elliott Bay Seawall project.
The $80 million tunnel machine has damage to the seals that lubricate and protect the $5 million main bearing. This bearing enables the ring-shaped drive shaft to turn the cutter, at about one rotation per minute.
Sand was found in the seal grease, and high temperatures have occurred in the main bearing, according to WSDOT interviews and quality-inspection records.
(Excerpt) Read more at seattletimes.com ...
Seems like an open ended problem. $5 million ... $80 million ... what will these delays and repairs cost ?
Thanks for posting this. I was wondering how Bertha was getting along. Poor girl, doesn’t sound good.
Can the machine be backed out of the tunnel?
I think it will back up about 18 inches on its own. For more than that you have to remove all the concrete liners in the tunnel that have been installed behind it. And even then you’d be dragging it out, ruining it.
Did they figure out what they hit that couldn’t be drilled? My money is on a new element, Hillarium.
Naked Bertha Photos:
>> many others machine like this are left/parked in a side tunnel
Well then, tunnel boring machines could use a design review.
Dump Bertha and hire illegals. They are experts in tunneling.
All those poor union guys who operate it....I guess they get paid while idle?
I too was wondering.
So it turns out it was not a rock or an old car but sand that caused the machine to stop?
When you're good you're good.
Do they have surfing on the Oregon coast? Bertha has a vacation going on!
The seals are bad that protect the main bearing. But the machine was running hot from the very beginning - so perhaps an installation or design problem. Of course drilling through the drill pipe may have furthered the problem and damaged the seal even more?
And even when/if they get the thing fixed, they still have most of the tunnel left to dig.
No, they put the tunnel lining up as the machine drills. The lining is smaller then Big Bertha.
It hit a steel pipe.
They knew that well-casing was there - although they may not have had the proper cutting heads installed at the time. But I guess that is pretty common do just drill through them. Some towns are filled with old oil and gas wells. (This one was a relatively small water well done to test the geology for the tunnel).
They had the over heating problem from very early on (before they hit the casing) - so I think there might be a bigger problem. This is the largest tunnel machine ever built. Although one would hope they did some test tunnels before they shipped it - but I doubt it.
5 years from now there will be a rusting hulk in a pit.