My cousin lived in Minneapolis/St. Paul for years. She’s in Colorado right now, but was recently planning to move back. Maybe that’s why I feel so shocked and horrified watching the CNN video of the I-35 Bridge collapse.
Or maybe it’s because something this stupid shouldn’t ever happen, and the engineer in me is just screaming that somebody somewhere had to have known.
My thoughts and condolences go out to all those affected.
*update* corrected link since CNN’s having fun moving the video around.
Making Light has a good thread on it.
The thing is, whoever it is who instructed the inspectors on what kind of damage was dangerous had to have been wrong. Either that, or at some point, someone made a big error that set up resonance problems or something, because with half the lanes of traffic due to resurfacing, there’s no way it should have failed.
I don’t know about that they were wrong. I think it is a matter of time being the ultimate test. In the grand scheme of things, we haven’t had these bridges for a long time. Its not like Transportation Departments did long term testing of bridge construction. Its kind of like medicines and medical procedures – the practices deliver the results we need now, but we have no idea what the long term results are.
Peri-renna – some good links in that one, thank you :)
I’m with Jamie. The engineering on bridges is a lot like the engineering on computers. You can do all the simulations you want and you can do everything possible to test, but at some level you can’t even observe what’s *really* going on, and one odd outlier out of the thousand-plus variables affecting the bridge *could* be the only one that could take it out…. which is within risk tolerances, until it happens.
ah, the magic screw principle. bugs bunny would be proud :)
Y’know what’s depressing? One day I was talking about the Milgram experiment, and someone else at the table commented that such experiments wouldn’t be needed anymore, because we can make computer models now. I wish I was exaggerating.
On more sober consideration, yes, I might be forced to concede the point – there are many ‘unknown unknowns’ to deal with. We won’t know until the NTSB finishes its investigations.