EoW May 2013

Transatlantic cable

† “We have extracted samples so we can have a clear understanding of what went on,” Mr Anziano told the Chronicle . “We don’t have a cost, but we will have a solution.” The problem did not particularly surprise him. “I’d be very surprised if you [were to look] at any large structural project that used fasteners and didn’t have an issue like that,” he said. “That’s why you have inspections.” † Messrs Matier and Ross of the Chronicle supplied some context for the latest problem with the eastern span, which has been under construction for more than a decade, and has a history of trouble and setbacks: notably when microscopic cracks were found in the steel deck sections being fabricated in China. That problem delayed key work on the bridge for months while new fabrication procedures were developed. There were also questions about the integrity of the welds on the piers of the new skyway section, leading to further inspections before that work was cleared. Plus, the Chronicle reporters observed, there was the accusation that an inspector who had worked on the bridge project faked seismic inspection reports on another, unrelated project: “That raised questions about whether he had taken similar shortcuts on inspections of concrete on [the Bay Bridge].” The faulty Bay Bridge steel rods originated in Ohio Last year, Bay Area motorists could glance up at huge billboards starkly asserting “Bay Bridge: 100% Foreign Steel.” The public-relations campaign, by domestic manufacturers and union groups, was intended to shame the two state agencies

The broken rods are not considered a structural problem with the bridge, Mr Rentschler told the newspaper. Nor, he said, are they expected to delay the scheduled Labor Day weekend opening in early September. All 288 rods may be replaced Although less con dent about meeting the opening-day date, toll bridge programme manager Tony Anziano did con rm that engineers are ‘pretty con dent’ the problem is not related to a design or a construction issue but to the quality of the steel rods (also known as bolts) themselves. “It appears to be a type of materials problem, the presence of hydrogen” making the metal brittle, he told the San Francisco Chronicle . As a result, the newspaper learned, Caltrans is considering replacing all 288 of the rods/bolts on the eastern span before is cleared for public use. (“Bay Bridge Inspections: Busted Bolts,” 27 th March). Chronicle reporters Phillip Matier and Andrew Ross noted that, unlike the Chinese-built deck sections, the bolts – ranging in length from 9 to 17 feet and 2 1 / 2 inches in diameter – were produced in the United States. The reporters said the problem was rst detected on a large concrete foundation and column that supports the easternmost end of the new single tower, where eight fabricated steel pieces are anchored into a concrete cap and into the bridge deck with the giant steel bolts. They were inserted in 2008, before the roadway decking was installed, making access to many of them di cult. † According to Mr Anziano, the toll bridges o cial, construction crews began tightening the nuts on both ends of 96 bolts – only to nd, days later, that some one-third of the nuts had popped loose, damaging the bolts.

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May 2013