For the first time, Hitachi Zosen executives discuss their view that Bertha was a “perfect” product and their commitment to finish the Highway 99 tunnel.

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The makers of tunnel-machine Bertha insist it would have made it all the way to South Lake Union long ago if that abandoned steel pipe, deep in the dirt, hadn’t tangled in the cutting teeth on Dec. 3, 2013.

The Highway 99 tunnel project lost more than two years because the drill overheated and stalled soon after, leading to a massive repair job.

Now that Bertha is churning through the dirt as intended, executives at Hitachi Zosen felt comfortable enough to discuss the episode, and their commitment to a finished tunnel, for the first time since work began. A team from the company was interviewed Friday by The Seattle Times.

The Japanese firm poured an estimated 70,000 hours into what it calls an unprecedented operation in tunneling history — engineering investigations, a crane lift of the machine’s 4-million-pound front end, disassembly next to Elliott Bay, and new bearing seals to protect the rotary-drive system.

Working six-day weeks, with engineers and technicians far from home, the company revived the $2 billion tunnel without knowing whether the firm would recover tens of millions of dollars.

Legal battles will go on for years about who is responsible for the damage that put Bertha so behind. Did the manufacturer make a machine that was tough enough? Did the state transportation department provide reliable information about soil conditions, and that pipe? Did the contractor, Seattle Tunnel Partners (STP), operate the machine properly?

Soichi Takaura, Hitachi Zosen general manager of tunnel-boring machines, said Friday the machine was “perfect” when it was shipped from Osaka, Japan, to Seattle in 2013, and that it worked fine before hitting the 8-inch-wide, 119-foot-long pipe near South Main Street.

That pipe was left over from groundwater studies in 2002 and 2010. A dispute review board said the Washington State Department of Transportation (WSDOT) should have done more to warn STP, but the board didn’t judge whether the steel-well casing caused Bertha’s breakdown, nor did it make any damage estimates.

The repairs, made above ground last year, created unique challenges for Hitachi Zosen because the new ring-shaped bearing had to be adjusted and machined to tolerances of a fraction of an inch. Ordinary temperature changes caused slight expansions and contractions, requiring extra measurements and quality checks.

“This program is, of course, a headache for me because I am in charge of the TBM business,” Takaura said through a translator.

“The company likes to contribute to the society through business. Because we’re a company, of course we have to do it with some kind of profit, but the top management wants to complete this project for the citizens of Seattle.”

Bertha recently achieved a winning streak of 40-foot workdays, pushing 1,500 feet north from Yesler Way to Spring Street during May and June. It’s now undergoing inspections of 700 cutting teeth. Only about 33 teeth have needed replacement so far, said STP manager Chris Dixon.

Takaura wouldn’t estimate how much money Hitachi Zosen spent fixing Bertha, saying he didn’t want to change the figure later. Some work is unfinished, he said, including investigation by “multiple experts” in Japan into exactly what caused the seal system to take on grit, and overheat three days after the pipe hit. Operators tried in vain to move the machine as it spun near its limits, at temperatures of up to 140 degrees, without grasping soil.

“It has not been finished,” he said of the inquiry, “but we are confident that, but for the accident, the TBM could have been able to complete the project as planned.”

A written follow-up statement said “there was nothing wrong with the seals in the original machine.” On the other hand, Hitachi Zosen’s 2014 repair plans, as presented by Dixon, showed that the company devised stiffer seal parts and fewer internal spaces where grit might penetrate.

“Gentleman’s agreement”

Hitachi Zosen’s costs might exceed the original $80 million price of the machine.

The company says it forwarded the money for parts, repair crews and the giant lift, while the STP partners (Tutor-Perini and Dragados USA) paid for a 120-foot-deep, concrete-lined access shaft to lift out Bertha’s front end in spring 2015. In a court dispute with insurance companies and WSDOT, tunnel contractors guessed the vault and repairs together exceed $143 million.

“We decided to proceed with the project, in a gentleman’s agreement, in good faith,” Takaura said.

“After an accident like this, most major construction projects would stop until responsibility for paying for the errors is resolved. That could have taken years. In order to avoid that, the top leaders of Hitachi Zosen and STP wanted to make every effort to support the project and to complete it as soon as possible.”

Takaura emphasized the firm has sold 1,300 tunnel-boring machines since 1967, and despite worldwide attention to Bertha’s problems, orders continue. “The client satisfaction is the most important policy,” he said.

Insurance companies have argued that Bertha was “underdimensioned,” meaning it lacked enough power for the Seattle job. And Martin Herrenknecht, founder of a rival German boring-machine maker, has called it the wrong type of machine, saying tunnel builders should have ordered his “slurry” machine that relies on fluid to soften the soil and keep pressures stable up front, and that carries boulder-cutting devices.

Bertha has cut effectively through Seattle clay this summer and not encountered large rocks.

“I understand that there are a lot of different opinions and decisions. I respect each of these companies’ decisions, but here at Hitachi Zosen, we do not think we chose the wrong machine or the strength was not enough,” said Takaura.

Bertha as art?

The tunnel bore is also grinding through greenbacks.

WSDOT makes monthly payments to contractors based on their actual progress. Payments surpassed $1 billion of the $1.35 billion contract a year ago, and neither the state nor Dixon would answer questions in the past week about how much is currently left for the state to pay. At some point, construction spending will exceed what the state will reimburse — unless contractors win money in court or in negotiations.

“Cash flow’s definitely a concern, but it’s not going to stop us from finishing,” Dixon said last week.

The state replied to Takaura’s comments in a statement Friday:

“While WSDOT generally does not comment on matters in litigation, WSDOT does not agree that Bertha was “perfect” or that an eight-inch steel well casing caused any significant problems for the massive TBM.”

“WSDOT is pleased that tunneling has gone well since the repairs were completed and that all parties are fully committed to the successful outcome of the SR 99 tunnel project.”

Contractors currently expect drilling to be finished early next year, with the tunnel opening to traffic in spring 2018.

Hitachi Zosen executives laughed and said they’re amenable to leaving Bertha’s 57-foot-diameter cutting disc in Seattle, when asked about selling or giving it to Olympic Sculpture Park or the Museum of History & Industry. City leaders have made no such overtures, nor has Dixon shown an interest in this sort of artwork.

But Takaura noted the company did leave a replica of a 46-foot cutter disc, as a monumentthat stands along Tokyo Bay.

Information in this article, originally published July 16, 2016, was corrected July 20, 2016. A previous version of this story incorrectly stated Hitachi Zosen left a cutter disc from another tunnel-boring machine as a monument along Tokyo Bay. The company later clarified that it was a replica.