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Re: AP: Wash. State bridge

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Friends at SEAINT,

I like to have a discussion on this forum on how we should reply to requests for interview. Please note that we as a faculty of public universities have to answer to reporters if their questions are in our area of expertise and we have information that we believe is correct on the very subject of their questions, especially when the question is directly related to public safety as this case was. I do not have the luxury of private sector employees who have the right to reject any request for interview even if they know a lot about the subject matter. Of course that is perfectly fine. So, with that in mind, I am interested in knowing your opinion , especially hearing your critical comments on following excerpts from news stories on I-5 Bridge collapse. I have only excerpted my own quotes but the URL for the full news story is also given. I really like to know which part you think is not correct and should not have been given to public.

1. From Wall Street Journal: "One Link Proves Bridge's Undoing " By JOEL MILLMAN, ZUSHA ELINSON AND JIM CARLTON, May 24, 2013
(URL:<http://cirrus.mail-list.com/seaint-seaosc/97312051.html> )
"This is not the sign of deteriorating infrastructure, this is a sign of vulnerable infrastructure," said Abolhassan Astaneh-Asl, a civil- engineering professor at the University of California <http://cirrus.mail-list.com/seaint-seaosc/52407369.html>, Berkeley." "This original design in those days was fine," he said of bridges lacking redundancy, "but today we should invest in getting these…out of the system." "The bridge has what is known as a "fracture-critical" design, which means that if any part fails, the whole bridge could fail, said Mr. Astaneh-Asl. "A fracture critical bridge is like a chain," he said. "Any link in this chain you cut, it's going to fail." ..... " Mr. Astaneh-Asl, the Berkeley professor, said the incident shows that states need to install height-limit pipes—like those in parking garages—on bridge approaches to fend off oversized vehicles."

2. From San Jose Mercury News: "Washington I-5 bridge collapse spotlights California's aging bridges"-By Pete Carey, Lisa Vorderbrueggen and Steven Harmon
By PETE CAREY,/LISA VORDERBRUEGEN and STEVEN HARMON, May 24, 2013
(URL:
" The bridge in Washington that collapsed was not rated structurally deficient and had a grade of 57.4 under a federal rating system. Anything below 50 would be considered especially worrisome, said Hassan Astaneh, professor of engineering and bridge engineering at UC Berkeley. More significant, he said, was the fact that the bridge was "fracture critical," an engineering term that means that damage to one structural component can cause the entire structure to collapse. The bridge that collapsed in Minneapolis in 2007 was also fracture critical, he said."

3. From ABC 7 (Local) TV in SF : "I-5 bridge collapse raises Bay Area safety questions" by Cornell Barnard and Heather Ishimaru, May 24, 2013
(URL: <http://abclocal.go.com/kgo/story?section=news/local&id=9115102>
"UC Berkeley engineering professor and bridge expert Abolhassan Astaneh says that's because the design is what's known as "fracture critical" -- if any one element fails, the whole thing goes. Back-up systems were harder to design without computers. He thinks there are a couple hundred fracture critical bridges in California, including the San Rafael and the old Carquinez bridges. "Fracture critical doesn't mean it's going to collapse tomorrow, what it means is eventually we have to budget as a nation to replace those bridges," Astaneh said. But could the self- anchored-suspension span of the new bridge have fracture critical features? Astaneh think that's a possibility, in part because the self- anchored suspension span is not anchored into land, but holds itself up with a single cable <http://abclocal.go.com/kgo/story?section=news/local&id=9115102#> looping around the structure."Even if bolts are good, the bridge is fracture critical," Astaneh said.

Best wishes as always.

Hassan Astaneh
www.ce.berkeley.edu/~astaneh

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