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[azure_armand]

Since when do bridges ever fall down? Can anyone think of any other example ever (I mean, without sabotage involved)? I've only heard of, like, jungle rope bridges, or model bridges made out of toothpicks and glue collapsing

Comments

[eqe]

Tacoma narrows. Various earthquake failures. I believe there have been a few bridges in India and Pakistan that collapsed after years of mismaintenance.

Wikipedia has a category:Bridge Disasters.

[alisgray]

didn't you guys have a freeway fall down earlier this year?

[eqe]

Yeah, a gas tanker crashed and caught fire under an overpass, melting the steel and causing the overpass to collapse. No fatalities, and the driver was just badly burned. Only took about 2 months for the reconstruction, because Caltrans bid it out as "$700k for the job, up to $5M in bonuses for early completion" or something like that.

[thisc0rrosion]

I'm having a similar reaction. Not the sarcasm, but just a strange sense of disbelief. The WHOLE THING? just dropping?

I mean, I'm sure an engineer can explain how every part supported every other part. But it just feels completely counter-intuitive. alien.

[birdfigment]

This image is useful in explaining what happened, in some part. Not why it started, but the sequence after the central span went.
http://www.startribune.com/10072/rich_media/1338795.html

[ilexcassine]

That is a good link.

[lokey]

Apparently the 35W bridge was completed just before an overhaul in the way such bridges were designed. Unfortunately the older design method made for a bridge that completely collapses an smaller portion of it gives out.

The 40-year-old bridge that collapsed in Minnesota last night, causing the deaths of at least seven people, was graded "structurally deficient" two years ago but was not scheduled to be replaced until 2020

[lokey]

Apparently the article has changed addresses-
http://www.timesonline.co.uk/tol/news/world/us_and_americas/article2186631.ece

[whitefox77]

"I always imagine that just one part of a structure would cave in, maybe just one pillar."

Most likely one small part failed first. People on the central span spoke of feeling strong vibrations for a few minutes before the collapse. This could easily been caused by individual beams bending, or individual rivets breaking. As each rivet or beam gives way the stresses it was supporting are transfered to the rivets and beams around it, putting them under more stress. Since those rivets and beams aren't in much better shape than the one that first broke, they break as well. It's a domino effect.