Spectacular failures

By ANA RIVAS  |  July 25, 2006

Now the Governor and his engineering team are saying that none of the 1,146 epoxy bolt hangers can be trusted… maybe all of the nuts were weak after all. Do you know what this "epoxy" glue is, where else it's been used? Do the panels HAVE to be so heavy?
Unfortunately, I have no idea where else this technique is used. What I can say about other ways of building and the weight of the panels is: In any design process, you would consider all the options that met your design criteria and winnow them down until you were satisfied that you were looking at the best option.  So at some point, I have to assume that all the alternatives that are being tossed around (use lighter panels, hang them some other way, etc.) were considered and rejected.

What's somewhat critical in understanding the process is for us to eventually find out what was rejected, why, and furthermore what were the design criteria in the first place?  (As a simple design example, the decision to use 3-ton panels obviously carries with it a new issue — namely, that the hanging system needs to be basically infallible, since the consequences of a failure are tragic rather than simply inconvenient.  So the question is, what do you gain by having panels that heavy, so that you're now willing to take on that new requirement? Presumably there's a good reason, but I don't know enough about the inner workings of that tunnel design to start speculating on what it might be.)

Can you speculate if it was a matter of bad math, too-fast construction, or too cheap materials?
Again, no idea.  Could be any or all, or some combination, or something else entirely that nobody's thought of yet.  Some failures can be traced back to a single batch of bad steel; others are caused by long chains of failures, the prevention of any one of which could have stopped the whole event

Would you drive through the broken tunnel?
Of course I'd drive in the tunnel. Just like I still drive a car, even though they've had failures in the past that have now been fixed. I have to trust that those responsible will learn from whatever happened and deliver a re-opened tunnel that's safer than it was before.

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