Contracting Shortcut Imperils San Francisco Bridge Safety
(Corrects that one type of bolt was considered, rather than one supplier, in first paragraph.)
A new span of the San Francisco-Oakland Bay Bridge, the most expensive public works project in California history, is vulnerable to earthquakes because state planners considered only one type of bolt for a type of steel fastener that subsequently failed, an investigative report concluded.
Thirty-two anchor rods, each about the diameter of a baseball and as much as 17 feet (5 meters) long, fractured when they were tightened. The Metropolitan Transportation Commission’s plan to open the 2.2-mile eastern section in early September has been put off indefinitely.
Construction on the Bay Bridge, which carries Interstate 80 between San Francisco and Oakland, started in 2002 and is already six years behind schedule. The price, once put at $1.1 billion, has soared to $6.3 billion. The new delay may cost the prime contractors performance incentives, while 270,000 drivers a day must depend on a bridge finished in 1936 and damaged in the 1989 Loma Prieta earthquake.
“We need to get the new bridge open and make sure it’s safe,” state Senator Mark DeSaulnier, a Walnut Creek Democrat and chairman of the Senate Transportation and Housing Committee, said by telephone. “That shouldn’t preclude us from looking at the whole project, looking at what we can do better, and holding people accountable.”
The Bay Area Toll Authority, the financing agency for the Metropolitan Transportation Commission, will meet today in Oakland and may discuss possible penalties against contractors and the timing of opening the new span, said Randy Rentschler, a commission spokesman.
The suspension bridge is designed to move slightly during earthquakes, rather than break, according to the report by the Toll Bridge Program Oversight Committee. In such an event, the bolt-like steel rods, manufactured by Dyson Corp. in Painesville, Ohio, help hold the road decks to the piers.
Besides excluding alternatives, engineers made the rods susceptible to breaking by specifying the wrong anti-corrosion treatment, according to the report.
“The specifications, the grades of material they ordered, were the grades we provided,” said Brian Rawson, the president of closely held Dyson, the low bidder. The company, which makes bolts, screws and fasteners, supplied components of the original Bay Bridge, where construction began in 1933. “They should have specified a higher-grade material.”
The state Transportation Department, known as Caltrans, shares responsibility for the failure with project contractors and engineers, according to the oversight report.
Engineers should have considered alternatives to the generally available steel rods, the report said, yet didn’t because of state contracting rules. Finding alternative materials might have required a “sole source” contract, discouraged by the state because it may cost more for exclusive designs or materials.
“Investigation into other types of high-strength steel rods, even if they might have required sole sourcing, appears to have been warranted,” the report said.
Tamie McGowen, a Transportation Department spokeswoman, referred questions to Andrew Gordon, a Bay Bridge spokesman who declined to address the sole-source issue.
The engineers approved dipping the rods in molten zinc at 850 degrees Fahrenheit (450 Celsius) to protect against corrosion. The technique can cause hydrogen to spiderweb through the metal and weaken it, Thomas Devine, a professor of Materials Science and Engineering at the University of California, Berkeley, said by e-mail.
The engineering team, a joint venture of T.Y. Lin International Group and Moffatt & Nichol Design, and state transportation engineers concluded that the rods were too long and heavy to be coated with zinc by a different method that might have prevented the brittleness, the report said.
Maribel Castillo, a spokeswoman for T.Y. Lin in San Francisco, declined to comment on the report and referred questions to the Bay Bridge spokesman. Moffatt & Nichol spokeswoman Tracy Russell didn’t respond to an e-mail message seeking comment on the report.
The 32 rods that cracked were among 2,306 on the entire east span. There’s no evidence that the other fasteners are vulnerable, Gordon said. Bridge designers are working on devices to take the place of the damaged rods. The fix is to be completed by Dec. 10, Gordon said, although officials haven’t determined when to open the new span to traffic.
Tax-exempt Bay Area Toll Authority revenue bonds maturing in April 2028 traded July 8 for the first time since May at an average yield of 3.84 percent, the highest since the debt was sold in September, data compiled by Bloomberg show. sold in September, data compiled by Bloomberg show. The penalty relative to AAA rated munis was 1.26 percentage points, close to the highest since issuance, the data show.
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