Tacoma Narrows Constructors, the company building the new Tacoma Narrows bridge, is not conceding that the bloom of “white rust” on stockpiled bridge wire is its fault.
“We are continuing to categorize and research the cause of this situation,” Erin Babbo, a TNC spokeswoman, said Friday.
In a Nov. 30 news conference, the state’s project manager, Linea Laird, stated definitively that the corrosion was caused by improper storage.
With four television cameras running, Laird flatly said, “We improperly stored the wire.”
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The state and TNC are partners in the project.
TNC withheld comment at the time, and Babbo now says the company is looking into all possible causes as it continues its worldwide search to replace the damaged wire.
Babbo would not say whether TNC has found any likely suppliers, saying only, “We continue pursuing an aggressive international procurement process.”
Initial estimates were that at least 2,400 miles of wire – and perhaps as much as 4,000 miles – were rendered unusable by corrosion of the zinc coating on the wire.
None of the wire used so far in spinning the bridge’s main cables was corroded, according to the state.
Replacing thousands of miles of wire still needed on the bridge will cost millions, industry observers say. It also could cause missed deadlines, which could get expensive. The matter of assessing blame might easily wind up in court.
Laird was not available for comment Friday, but Claudia Cornish, a state Department of Transportation spokeswoman for the project, acknowledged that Laird’s analysis might have been premature.
Cornish declined to speculate on other possible causes for the problem with the wire, but noted, “It’s a long way from Korea to us.”
The 19,000 miles of pencil-thin wire, which is being looped back and forth across the towers to form the new bridge’s main suspension cables, was made from Japanese steel at a factory near Pusan, South Korea.
The wire was coiled in 4-mile lengths, wrapped in plastic and shipped to Washington by ocean freighter.
TNC and the state had quality control inspectors at the Korean plant, and verified the wire was manufactured and coated correctly.
Most of the wire was stored outside once it reached Tacoma, some for more than a year.
Throughout last week, TNC crews sorted through wire at a holding area near the bridge’s Tacoma anchorage, separating good from bad.
Meanwhile, spinning crews continued to work with undamaged wire, building the bridge’s south main cable.
Spinning crews had been working on both cables simultaneously, but TNC managers decided to finish the south cable with the remaining good wire and hold off on the north cable until replacement wire can be found.
TNC’s internal schedule had called for finishing both cables this month.
The company’s contract with the state does not specify a time for cable spinning to be completed. TNC’s next contractual deadline is May 7, when it is to have the first deck section in place.
Cornish said the transportation department so far is not overly concerned that the project will be delayed.
“We know that TNC is working very hard on the problem,” she said.
But, she added, “There’s a tremendous amount of work and a lot of questions to be answered before we’re ready to talk about how we move forward from here.”
Rob Carson: 253-597-8693