This story has 9 updates
SEATTLE — The tunnel-boring machine Big Bertha has been stuck in neutral for more than a month now, and the Washington State Department of Transportation still doesn’t know why.
On Wednesday, three crews of five trained divers were to work around the clock to get up close to Bertha’s cutter head using a hyperbaric chamber.
“The workers need to go into these hyperbaric manlocks; they go in there and increase the pressure,” said Seattle Tunnel Partners project manager Chris Dixon.
There’s up to 50% more pressure underground than on the surface so it will be a slow and careful process for divers.
“We a very confident that it’s going to give us the ability to assess what the situation is,” Dixon said.
But underground, crews will have limited vision.
“We are not going to be able to determine maybe what’s 5 or 6 feet out in front,” Dixon said.
As WSDOT waits for a solution to get Bertha moving again, the pressure is on the contractor, Seattle Tunnel Partners, which could possibly face a lawsuit.
State Transportation Secretary Lynn Peterson sent a letter to lawmakers and a part of it reads:
“WSDOT has had concerns about the machine’s operations and critical systems since its launch on July 30, 2013. We have discussed these concerns with STP frequently over the past five months and this week sent a formal letter stating our concerns and asking STP how they will address them prior to tunneling under the viaduct and downtown. We are providing you with this information in lieu of a copy of the letter because it could be the subject of a potential future litigation between WSDOT and the contractor.”
The agency wanted a series of answers from the contractor by Wednesday, including how they would make up for lost time.
“They are going to blame somebody. You know, somebody is going to pay for this,” said Luigi DeNunzio, owner of Al Boccalino restaurant in Pioneer Square.
Business owners in the area say their livelihoods depend on a quick solution.
“Whether the project works or doesn’t work, we are at their mercy,” DeNunzio said.
More than a month after the project stalled, crews still don`t know what’s blocking Bertha.
They say it’s possible it’s a long steel pipe. Earlier this month, they discovered a part of it protruding from Bertha’s cutter head.
WSDOT says the pipe was installed by their crews in 2002 to study the flow of groundwater but it might not be the only problem.
“Absolutes in this kind of industry is not where we want to go. It is kind of like a medical diagnosis, they have to do a certain amount of things,” WSDOT program administrator Todd Trepanier said.
Seattle Tunnel Partners says the hyperbaric intervention could take several days and they hope to have a better picture by then.
Peterson will appear before the state Senate Transportation Committee Thursday afternoon to try to answer legislators’ questions about the project.
SEATTLE — The deep-tunnel boring machine tasked to dig the new State Route 99 tunnel was at least partially blocked by a steel pipe, the Washington State Department of Transportation said Friday.
The tunnel machine, nicknamed Bertha, has been stalled since Dec. 6. Crews working to determine what stalled the machine found a 8-inch diameter steel pipe protruding through one of the machine’s many openings in the cutterhead Thursday.
Officials said the pipe was installed by the WSDOT in 2002 following the Nisqually earthquake to better understand how groundwater flowed through the area. The pipe was known to WSDOT prior to the dig.
WSDOT said other potential factors could still contribute to the blocking of boring machine, such as changing soil conditions that may have caused excessive wear on the cutting tools. It is still possible other objects are blocking the cutterhead, WSDOT said.
Bertha will remained stopped until the steel pipe can be removed. It was “too early to speculate” on when work would resume.
The boring machine has stalled several times, and is slightly behind schedule. The machine has bored approximately 1/10 of it’s scheduled work.
SEATTLE — It’s been almost a month since the world’s largest tunneling machine along Seattle’s waterfront came to a screeching halt, stopping work on the tunnel to replace the Alaskan Way Viaduct.
The Washington State Department of Transportation was hoping to get deep enough Thursday to figure out what is exactly blocking Bertha.
There is a lot of speculation, but David Williams, a writer specializing in urban geology who is studying the area where Bertha is stuck, said it could be similar to the landmark found in Seattle’s Wedgwood neighborhood known simply as the Big Rock.
“Well, it’s very unusual,” resident Gary DeGorgue said of the Big Rock.
Sitting at the corner of 28th Avenue NE and NE 72nd Street, the rock is more than 19 feet tall.
“Awesome, I really think it is,” resident Carol Cassinelli said.
But something similar could be the reason why Bertha, a 7,000-ton machine, is at a standstill 60 feet below the surface miles away.
“From a geological point of view, that’s the best guess,” Williams said.
“When the first Europeans arrived, where Bertha is right now was water,” Williams said.
From the Cascades to the Olympics, the landscape was covered with ice more than 16,000 years ago. When the glaciers started moving, they carried rocks along the way.
“Those could be any size. As you can imagine,you have a 3,000-foot thick massive ice, it can push anything in its path,” Williams said.
That’s why geologists call the boulders a glacial erratic.
“A glacial erratic is a rock that’s pushed from point A to point B. As the glacier pulls back or retreats, it leaves behind the rocks, the most famous one is Plymouth Rock in Massachusetts,” Williams said.
WSDOT has 10 de-watering wells, pumping out water to lower the pressure so divers can see for themselves. For now, all experts can do is look to history for an answer.
WSDOT did not share how far they got on Thursday but they are holding a press conference on Friday at 1 p.m to update the public.
SEATTLE — Crews are taking the first step toward identifying and removing the obstruction that’s kept Bertha sitting idle for a week. Seattle Tunnel Partners is installing eight wells 120 feet deep at the construction site near the SR 99 tunneling machine.
An unknown object forced officials to stop Bertha about 60 feet below the surface between South Jackson and Main Streets, according to WSDOT.
The contractor says the wells will lower water pressure in the ground enough to create a safe environment for workers to assess the situation.
“We’re confident STP has the right people and the right approach in place to safely determine what’s causing the obstruction,” said Matt Preedy, Alaskan Way Viaduct Replacement Program deputy administrator. “Once they know what the obstruction is, our contractor will be able to select the best path forward.”
The contractor began installing the wells Thursday and hopes to begin inspecting the machine by late next week.
Since its start on July 30th, Bertha has dug out more than 1,000 feet. That is about one-eighth of the tunnel’s total distance.
SEATTLE – Four years ago Mayor Mike McGinn rode to victory by opposing the $3 billion viaduct tunnel project. At the time he said it was fraught with risk and any problems could easily balloon the cost.
Today, in an extended interview on Q13 FOX, McGinn reflected on his position.
“I was prepared, you know, to proceed with the tunnel agreements with the state if the state would agree to pay cost overruns,” he said. “Well here we are, Bertha’s stuck, the state still doesn’t want to pay cost overruns.” McGinn defended his handling of the tunnel project during his first 18 months in office, leading up to the Tunnel referendum that was approved in 2011. “I was just trying to ask a question that mattered,” he said.
McGinn resisted any I-told-you-so reaction. “Nobody likes that from anybody, including me,” he said. “We have a situation we are facing right now where the public and all the elected officials, Ed Murray’s one of the chief proponents of this, said we’re going to go ahead despite the risks.” McGinn hopes the problem can be resolved quickly. “They gotta figure out how to get to the other end of this tunnel without going way over budget.”
SEATTLE – Some people are questioning the safety of the Highway 99 tunnel machine, after a large sinkhole opened up in downtown Seattle.
When the world’s largest tunneling machine starts digging beneath a major city, there are bound to be issues. Early Thursday morning, a seven foot deep sinkhole opened up on King Street.
“This was not out of the realm of expectation,” says Matt Preedy, Deputy Program Administrator for the Washington State Department of Transportation.
The sinkhole was immediately filled in, and Bertha kept digging.
Today, WSDOT tried to reassure people working and living downtown that the project is going as planned. They say right now, the soil they’re moving through is loose fill. Until they get down to more compact soil around Jackson Street, sinkholes are a possibility. But they say they’re prepared for that.
“We have a variety of monitoring equipment on all the utilities. We have a variety of monitoring equipment on the surface street itself,” says Preedy.
That doesn’t make downtown resident Matthew Hall feel better.
“I live right there, my office is right there, who knows what else is going to happen?” he says. “If it happened down here, what if it happens under one of the big office buildings or whatever?”
WSDOT says Bertha will be much farther underground by the time it reaches the viaduct early next year.
“What has happened down here is not able to happen there,” says Preedy.
But they’re still planning on closing the viaduct at that point, to be safe.
Shelli Park, who’s getting ready to open a new business downtown, is hoping WSDOT’s safety plan will work.
“I think I trust just enough that there’s been forethought and the buildings aren’t going to be in any danger,” she says.
Bertha started digging on July 30. She’s traveled about 460 feet since then.
SEATTLE — A 7-foot-deep sinkhole was discovered in a restricted area south of Seattle’s King Street Thursday as Bertha, the Alaskan Way tunneling machine, was boring beneath the area, officials said.
“Located in the construction yard just south of King, the sinkhole was about 15 feet long, 20 feet wide and 7 feet deep,” transportation officials said. “The hole was quickly filled in as Bertha continued on her way, but not before it illustrated why our contractor spent $53 million building a protected area at the start of the tunnel drive. If ever there was a good spot for a sinkhole, it’s here, in a restricted area protected by underground walls.”
The Bertha blog said some of the soil near King Street is glacial till, which is good for tunneling, but a layer near the surface is fill material dumped in 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, it said.