Caltrans documents tell of Bay Bridge woes
Jaxon Van Derbeken | San Francisco Chronicle
Updated 11:46 pm, Friday, June 21, 2013
Newly released Caltrans documents reveal there were quality-control problems with hundreds of the steel rods and bolts installed on the new Bay Bridge eastern span, including one batch that was improperly treated with brake cleaner and another with an aerosol product called Zinc-It.Caltrans released the documents Friday in response to media inquiries made after 32 high-strength rods that had been coated in zinc - a process known as galvanization - cracked in March.
The rods had been made brittle by hydrogen, which can seep into steel either during galvanization or when it is installed in a moist environment such as San Francisco Bay.
More than 2,000 additional rods and bolts installed on the bridge also were galvanized and made of high-strength steel, raising integrity questions that have jeopardized Caltrans' plans to open the bridge to traffic Sept. 3.
The breakdowns revealed in the newly released documents occurred in various phases of production. The rods and bolts were to be used throughout the bridge, including to bind the cables together, to anchor the tower, to hold down seismic stabilization structures and to tie cables to the anchorages.
The majority of the rods and bolts on the span were supplied by Dyson Corp. of Ohio. The documents show that in 2011, a Caltrans inspector visiting a Missouri yard of Dyson subcontractor Monnig Industries found workers spraying the threaded ends of the rods with brake cleaner before they were to be galvanized.
Blasted with grit
The rods were supposed to be blasted only with grit, to avoid having hydrogen contaminate the steel before it was dipped in molten zinc.
Monnig's general manager, Ryan Monnig, was told brake cleaner wasn't an approved cleaning method, according to the Caltrans inspector's report. "Monnig stated they had an e-mail from Dyson Corp. stating it was acceptable," the report said.
Asked for a copy of that e-mail, Monnig said he was unable to provide one because of a "recent computer issue," the report said.
The inspector and a representative of the eastern span's main contractor, American Bridge/Fluor, told Monnig to stop using the brake cleaner. But Caltrans didn't reject the batch of rods, the documents show.
It's unclear from the documents whether Monnig used the same brake cleaner on a batch of 96 rods delivered to the eastern span project in 2008. The 32 rods that failed in March were part of that batch.
Russell Kane, a corrosion expert in Texas, said brake cleaner could leave a residue that would make it more difficult for the protective zinc to adhere to the steel. "That would lead to areas that could be prone to corrosion," Kane said.
Another snafu
Caltrans inspectors found another kind of galvanization snafu in a January 2007 inspection at a construction yard in Ingleside, Texas, according to an agency quality-control report. There, the main contractor building the bridge tower's foundation, Kiewit Offshore Services, had received 424 bolts and was touching up flaws in the galvanization with a spray-can product called Zinc-It Instant Cold Galvanize.
Caltrans specifications bar aerosol products from being used to repair galvanization flaws.
Kiewit Offshore quality-control manager George Barnhill admitted in the letter to bridge officials that the company's workers had used the banned product to "touch up" damaged areas of the rods. He said the company had agreed to remove the product from the job site and ban its future use.
Caltrans officials concluded that the company had not known about the no-aerosol rules and said the spraying amounted to an "isolated case."
Source: http://www.sfgate.com/bayarea/article/Caltrans-documents-tell-of-Bay-Bridge-woes-4615826.phpCheck out http://groups.yahoo.com/group/californiadisasters/
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