The New Bay Bridge: Is It Safe?
OAKLAND (KPIX 5) — Is it safe?
That’s the question as we draw closer to when the new eastern span of the Bay Bridge is supposed to open.
The old bridge carries 270,000 vehicles a day, making it the second busiest crossing in the country after the George Washington Bridge in New York. The partial collapse of the eastern span in 1989 led to construction of the new bridge with its “lifeline” designation – meaning it is designed to quickly reopen following a major earthquake.
But bad bolts have dealt a heavy blow to public trust of the new bridge.
“We need to make sure this bridge is safe, demonstrate it, and prove it,” said engineering professor Bob Bea. Co-founder of the Center for Catastrophic Risk Management at U.C. Berkeley, he has spent years analyzing disasters – from the break up of the Columbia space shuttle to the blast on BP’s Deepwater Horizon oil platform.
When Bea talks about bolts on the Bay Bridge, he starts with a story about oil tankers.
“Those ships became known as a box of crackers,” said Bea.
Back in the 1950s and 60s, tankers were built of super strong steel. But then, Bea said, “They had so much trouble with cracks of many types, many places.”
The super-strong hulls were under attack by the very stuff they were floating in: the hydrogen in water. By the 1970s, engineers realized that the stronger the steel, the easier it is for hydrogen to create tiny cracks that make it brittle. The cracks grow under heavy loads or tension until the steel suddenly breaks.
Which is why oil tankers are now made of mild-strength steel. And why both federal and California standards warn against using high-strength steel parts on bridges – especially over water.
So why did Caltrans decide in 2002 to use high-strength steel bolts that would be most vulnerable to hydrogen corrosion?
“You come up with the design requirements, and then you come up with the fixtures that meet those design requirements,” explained Caltrans director Malcolm Dougherty, who said the bridge needed the extra strength. “So the alternative would have been using lower strength bolts and using more bolts. Or using this many bolts and using higher strength bolts. But at the time, again, these were bolts that were used in other projects – they were bolts that were used in other projects by us, and very successful. So it was not much of an issue, and it was a fully evaluated decision before we went forward.”
High-strength steel is what allows the new bridge to be much more streamlined than its cousins around the bay. The Golden Gate Bridge, for example, is held together by over one million rivets. The new suspension span uses an entirely different technique: welded steel and 2,306 high-strength bolts.
“The bolts are in critical locations,” said Bob Bea. “They’re holding critical parts of this structure together. And if they don’t function properly, the system can fail.”
To be clear, Bea does not think the bridge will fall down from everyday use.
But the Hayward fault is just seven miles away from the new suspension span, where 32 high-strength bolts holding earthquake safety devices broke last March.
The reason? Hydrogen embrittlement.
The broken bolts put Caltrans on the hot seat, and bridge safety in the spotlight.
California legislators demanded to know why Caltrans had gone outside standard specifications.
“The standard specifications are the specifications that we use for our everyday bridges,” Caltrans director Dougherty told the state Senate Transportation Committee. “This is not your everyday bridge.” Dougherty added that using high-strength steel bolts “was a decision that was made eyes wide open.”
But according to U.C. Berkeley metallurgy professor and corrosion expert Thomas Devine, “The materials that were used in these bolts were not the appropriate material to use.”
Devine says bridge designers made several mistakes. First, they ordered bolts that were too hard on the outside, making them susceptible to hydrogen cracking. Then they galvanized the bolts, leaving them more vulnerable to hydrogen. And finally, they installed the bolts without enough testing.
Caltran director Dougherty says testing on the bolts met industry standards at the time, but admits that it was inadequate. Now he says Caltrans is testing nearly all the remaining bolts, including plans to soak some in salt water to simulate decades of corrosion. And those broken bolts? They’re buried in concrete. So the earthquake protection they were supposed to provide will be replaced by a steel saddle tied down by steel cables – at a cost of five to ten million dollars.
So far, Caltrans says it has found no other broken bolts. But hundreds may need to be replaced anyway because of their high strength.
“You can never – and this sometimes makes people nervous to hear – that you can never guarantee that a high-strength steel, or a high-strength aluminum alloy, will NOT fail, by hydrogen assisted cracking,” said Thomas Devine.
Still, Malcolm Dougherty insists the new bridge will be much safer than the old bridge in an earthquake, and points to advanced safety engineering such as shear link beams that are designed to bend, even break, to absorb shock to the bridge tower; and hinge-pipe beams that will allow the roadbed to flex. And to prove it will all work, Dougherty says his team has used more computer modeling than ever conducted on any other bridge. Caltrans claims its data shows that the new bridge can withstand much more ground motion than the old one.
“I absolutely feel confident that this bridge is safe,” said Dougherty. “This bridge, besides no collapse, is also designed for operability in a very short amount of time, to get lifeline supplies into the city of San Francisco, or get people out of the city of San Francisco, because this bridge is that important.” He added, “When a large earthquake hits? I think this is one of the places I’d rather be standing.”
“You need to approach an engineering challenge like this with a fair degree of humility. And I don’t think we had nearly enough of it when we started,” said Steve Heminger, head of the Metropolitan Transportation Commission, which manages Bay Area bridges.
If you’re looking for the man in charge of the new Bay Bridge project, Heminger is it.
When former Governor Arnold Schwarzenegger and the California legislature got fed up with billion-dollar cost overruns on the new bridge in 2005, they took full control away from Caltrans and handed it to a brand new committee to oversee costs and construction. Heminger is now the chair of the Toll Bridge Project Oversight Committee (TBPOC), sharing control with Caltrans director Malcolm Dougherty and California Transportation Commission executive director Andre Boutros.
The finish line for completing the bridge was within sight when the story of the bad bolts broke last March. Suddenly the Labor Day opening was in doubt, and the very safety of the bridge under scrutiny.
A 32-page report by retired Bechtel metallurgist Yun Chung analyzed the bolt problem and accused Caltrans of “bad materials engineering.” Furthermore, wrote Chung, “the confusion surrounding these…failures reflects the lack of expertise by Caltrans.”
State Senate Transportation Committee chair Mark DeSaulnier blasted the agency for not being up front with the truth. “There’s a culture in Caltrans that is not transparent;” said DeSaulnier. “It is not responsive enough to the people they work for.”
The Transportation Committee held a hearing on the bolts in May and put Steve Heminger and Malcolm Dougherty under oath to explain what went wrong.
“What is Caltrans going to do to earn the trust of the public? For them to say, look, this is a safe bridge, we are comfortable going across,” asked state senator Anthony Cannella at the hearing.
Dougherty responded, “I think that is one of my enormous challenges: to raise the confidence not only in the legislature, but in the public.”
Caltrans investigated the broken bolts in its own report. But the Transportation Committee wanted more and asked the Legislative Analyst’s Office to form an independent expert review panel. Steve Heminger launched a separate investigation by the Toll Bridge Project Oversight Committee, and he arranged a seismic peer-review team to probe the safety of all the bolts on the bridge. He also brought in inspectors from the Federal Highway Administration to examine the proposed fix and review findings from the other investigations.
“They are on the job now,” Heminger told the Senate Transportation Committee, “and will be reviewing the job that we do, the decisions that we make, so you have that arm’s length assurance that it’s not just us that you have to take the word for.”
But there are more than bad bolts to examine. Hidden inside the skyway section of the bridge are tons of high-strength steel cables that help support the concrete roadways. In 2006, some of those cables were accidentally exposed to water, making them susceptible to hydrogen-assisted cracking.
And last year, another problem: inspectors found what they called “imperfections” in welds at the base of the tower.
Caltrans says it has fixes for these issues. But critics insist there is no proof those solutions will hold up.
“Look, I think there’s a lot of public concern,” said Heminger. “And I don’t blame people. Because, when you read some of the newspaper headlines— We had a story not long ago about the railing for the bike path. As if that was as important as these 20-foot, 3-inch diameter bolts holding down a major seismic device on the bridge. They’re not the same issue.”
The bike path railing is fixed, but the publicity was another hit.
“It is a bit of a death by a thousand cuts,” said Heminger. “And I think this is one of the questions you face when you lose a measure of public confidence. And I think this project has done that, unfortunately. And we need to earn that confidence back. We need to earn that trust back. And I think the first way we do it, the best way we do it, is to complete this investigation and honestly and candidly say: What went wrong and why. And secondly, we’re going to take care of the problem.”
From an original plan to build a $1.1 billion bridge by 2003, to a $6.4 billion project not yet complete in 2013, this is the most expensive public works project in California history. And drivers on all Bay Area’s state-owned bridges are paying more than they used to. A one-dollar surcharge to pay for the new bridge was added to the toll in 1998. Another dollar was added in 2007. And a third dollar in 2010, which is earmarked for retrofits on the Dumbarton and Antioch bridges.
There is no set end-date for those surcharges. The extra dollars, along with fuel taxes and revenue from voter-approved bonds, have to pay 95% of the cost of the new bridge. Only 5% comes from the federal government. And it will be just enough, with none left for another mega-project like this one. In fact, you could say all Bay Area bridges, roads, and transit systems will be in “maintenance mode” for years to come.
“I think job-one in the Bay Area is to take care of what we’ve already built,” said Steve Heminger. “We’re going to spend almost 90% of all the money we expect to be available over the next 30 years – that’s federal, state, private, you name it – 90% of it is going to operate and maintaining the current system.”
WHEN WILL THE BRIDGE OPEN?
Steve Heminger says July 10 is his “drop-dead date” for announcing whether the bridge will open on September 3 or be delayed. That July 10 date is when results from the investigations are supposed to be complete. That’s also the day the Bay Area Toll Authority Oversight Committee meets, giving Heminger, Malcolm Dougherty, and Andre Boutros a public forum to present findings and answer questions.
So what’s the answer to the key question: “Is this bridge safe?”
The builders say it is.
Some outside experts say it’s not.
The final decision to open the bridge will be technical, but it will also be political. It will come from Heminger’s committee and California governor Jerry Brown.
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