Bridge Over Troubled Bolts: UC Berkeley experts raise safety concerns about new Bay Bridge

As the Bay Area celebrates the opening of a new Bay Bridge—an eastern span that transportation officials are hailing as elegant and seismically secure—UC Berkeley engineers are expressing serious misgivings about whether the structure is safe. And at least one professor labels it far less stable than the old bridge. 

Cal professor of civil and environmental engineering Abolhassan Astaneh-Asl told us only a few hours before Wednesday night’s closing of the old span that he believed the new span is so deficient in its design and execution that it is much less safe than the old one. It was Astaneh-Asl who led a Cal team that investigated damage to the old Bay Bridge after the 1989 Loma Prieta earthquake and determined that the structure’s foundations were sound.

The old Bay Bridge, unlovely as it is, was engineered for strength and durability, Astaneh-Asl said; the only significant failure during Loma Prieta was the collapse of a section of the upper deck, which he attributed to some relatively minor and localized truss shifting.

He said state and regional transportation officials “have been telling everyone who will listen that the old bridge is unsafe, and now it’s widely accepted. That’s simply not true. For one thing, Caltrans knows that the Federal Highway Administration requires the immediate closure of a bridge if state transportation department officials conclude it is unsafe. Caltrans has been claiming the old bridge is unsafe for ten years. If they truly believe that, then they willingly broke federal law, because they kept the old bridge open.” 

The new bridge, by contrast, is a ‘fracture critical’ bridge, Astaneh-Asl said. “That means that if a single component fails, the whole thing comes down. Fracture critical bridges have been out of favor since the 1960s. And when you look at this new span, there are many things that can go wrong.”

But transportation officials maintain that the opening of the new Bay Bridge is cause for celebration, and that despite a series of snafus over several years, the result will be a beautifully designed and seismically safe bridge—so safe that it will withstand a once-every-1,500-years earthquake.

The most recent of those snafus struck in March, when three dozen earthquake-safety anchor bolts were discovered to have snapped. Replacing them was expected to yet again delay the opening of the new Bay Bridge, this time until at least December. 

But the state moved forward with a temporary fix: steel plates rigged in the vicinity of the fractured anchor bolts. These devices, state engineers concluded, will minimize bridge movement during an earthquake. The plates must suffice until a more robust steel “saddle” is installed as a permanent anchoring mechanism.

This solution seemed to satisfy everyone—everyone who counts, anyway. Vincent Mammano, the administrator for the California division office of the Federal Highway Administration, wrote that he was impressed by the state’s efforts, and saw no reason to delay opening the span to traffic while the long-term repairs were completed. That pleased the Toll Bridge Oversight Committee, which subsequently voted unanimously to green light the September 3 opening.

“We had four independent groups all verify and endorse this idea on their own,” said Andrew Gordon, spokesman for the Bay Bridge project and a guest on KQED’s Forum program. “We had the Seismic Safety Peer Review Panel, which is made up of world renowned seismic experts, we had the Federal Highway Administration, and two engineering firms all on their own review this proposal to use the shims—these steel plates—in this way.

“And they all came to the same conclusion: That we could use the shims to protect the bearings that are under the bridge while we’re fixing those broken bolts permanently, and also use those to achieve the level of seismic safety necessary to get traffic onto the bridge.”

Defenders of the new span have suggested that Astaneh-Asl bears a grudge because his own design proposal for the Bay Bridge was not selected. He is perhaps the most outspoken engineering critic of the project. But he is hardly alone.

Emeritus professor of civil and environmental engineering Bob Bea—one of the nation’s foremost authorities on large project risk management—responded to our query with an email in which he took pains to separate the engineering wheat from the chaff of media hysteria and political posturing.

“This is a very challenging engineering problem that needs to be carefully addressed and the concerns properly managed,” he wrote. “It is not a time for political rhetoric that will further contribute to the fog…” That said, Bea observed that tests on the bridge and its supporting components were underway, “…(and) yes, the results are encouraging. But there are significant concerns with the validity of the testing and the testing results.”

Further, Bea wrote, “…the problems with this structure are much more extensive than the seismic support bolts. (There are) corroded post tensioning tendons in the concrete girders (and) flawed welds in the suspension span support tower.  (There are) lots of identified defects with high uncertainties concerning their effects on performance and safety. And to my knowledge, there still has not been a comprehensive analysis of the potential defects on the ‘safety’ and ‘performance’ (short and long-term) of our new ‘signature’ bridge…”

Considering its location in one of the most seismically active regions on earth, the new Bay Bridge project has seemed cursed for years. Almost from the beginning, there were questions about its design. Then came financial problems at Caltrans, worries about the soundness of many of the welds on the new bridge’s supporting members, and then the snapping of the very bolts designed to ensure the seismic safety of the span. UC Berkeley professor of material sciences Thomas Devine and Bea both expressed concerns about the safety of the bolts and other issues, and urged a thorough assessment.

A quarter century has passed since the Loma Prieta quake struck. The new Bay Bridge, when it debuts next week, will have been under construction for two decades and come in hugely over budget, at a cost of more than $6.4 billion

As for Astaneh-Asl, he continues to cite his original concern over basic design: self-supported spans are inherently unstable, he said, because they are not anchored to the earth like conventional suspension bridges. Then there is the matter of the anchor bolts – they’re all a problem, he said, not just the ones that snapped.

“We know the steel they used has an issue with hydrogen embrittlement, which makes the bolts inadequate to the stresses they could face,” he said. “There is also the matter of the 20 main welds that connect the legs of the tower to the tower’s foundation. These are each about 30 feet long, and they have hundreds of visible cracks—and at least one of them is seven inches long. That’s incredibly bad news. Cracks in welds are always a problem, but you usually can only detect them by sonic testing—and these can be seen with the naked eye.”

Everything considered, continued Astaneh-Asl—“and by that I mean the 2,300 faulty anchor bolts, the cracked welds, the corroded tendons in the girders, the basic flawed design—there’s no doubt in my mind that the old bridge is much, much safer than the new bridge. (The new span) should not be opened to the public.  All the evidence that Caltrans has indicates this bridge will collapse when the Hayward Fault ruptures.”

—Glen Martin

California Magazine delved into the troubled history of the redesigned Bay Bridge in its Summer 2013 issue and also here. We also filed a follow about the bitter dispute between Professor Astaneh and Bay Bridge officials here.

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Comments

Whenever you enter a massive project like this and your immediate concern is cost not safety, problems are likely to arise. The new Bay Bridge should have been constructed by union steel workers using American steel from Pittsburg. God help us if Caltrans is wrong.

It was built by union iron workers and the American steel industry has gotten so little investment in modernization that it can no longer make the steel that was required for the bridge. Thank Wall St. for that!
I am amazed that only one other comment besides mine has been posted. The potential for disaster if the bridge should fail should get many comments. Then there is the political and financial fallout that will occur should the bridge be faulty. As a former united auto workers union member, and a operating engineer union member ini the public sector division, I am appalled at the ignorance of our young generation in regards to what being a union member brings them. I guess they are so caught up in working two and three jobs and believing the BS spread by the conservative right regarding union benefits they just don’t get it. Read your history people, unions made this country and they can save it again if you have the guts to fight for fair wages and benefits. That’s enough, probably falling on deaf ears anyway.
I too am a union member and proud of the fact. Collective bargaining prevents employers from divide and conquer tactics, thus helping to keep the middle class alive by ensuring fair wages and benefits for a fair day’s work. Still, the (union) ironworkers can only build the bridge that the contractor tells them to build. They are not engineers. The men and women of the local ironworkers (I’m in a different union but I know some of them), take a great deal of pride in their work and strive to do the best job they possibly can, while strenuously reporting any problems they notice. Who do you think noticed the broken bolts? A bad bridge is not their fault. Also, some of the welds were done in China (need I say more). If the bridge falls down we deserve what we get because we listened to the bean counters.
We all know that Caltans are experts in such kind of jobs. How come their findings on the bridge is taken for granted? Why is the bridge still open? Are they waiting for accidents to happen before they close the bridge? A lot of bridges around San Francisco, including walking bridges, are found to be functioning obsolete. I hope they (authorities) take time to review these issues because safety is at stake in this matter.
Fabricated in China—that says it all.
As far back as 1980, I was selling tooling to fabrication shops in south Texas where “Buy American” was taken very seriously (burnt Toyotas and so on). The shop managers would sheepishly tell me that they were buying Chinese steel because the American steel (which they were willing to pay a higher price for) was so full of carbide impurities as to triple their cutting tool costs. Wall St. insists on a certain % of return on investment; year in and year out that makes investment in modernisation a stock price killer. So we have become a nation that is slave to the lowest bidder, and ensuring that we get substandard everything (with a purposely designed obsolescence included). It brings to mind something my father told me: “When you pay peanuts, you get monkey business.” My own experiences dealing with ‘lowest bidders’ has only reinforced that opinion. So… If our Chinese bridge falls down, as I said before, we deserve what we get.

I just heard the phrase “Fracture Critical” this morning on the radio. So I knew what to type in on Google to find this and other articles that voice similar concerns. It isn’t that the public doesn’t care. It’s that there is too much information being disseminated and too many news sources. As for the Bay Bridge, Barbara Simpson had Astaneh Asl on her radio show several times discussing this after the Loma Prieta earthquake. I’m saddened, but not surprised that nothing is being done to properly re-build the bridge. As for me, from now on I will use Richmond/San Rafael bridge when travelling to the east bay!

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