MPLS Bridge Collapse
I got a call from my buddy Brian around a quarter after six tonight, hopped on my bike and flew down through the U of M campus to the Cedar Ave. Bridge on 10th. This is what I saw.
I'm still in shock, I take that bridge almost everyday. One of my best freinds was driving home from work and went over it through road construction and rush hour traffic just minutes before it collapsed. So far, no one I know was involved, but it's horrible knowing that loved ones were lost and many more were and still are in critical condition, overflowing the hospitals in the area.
35W bridge was such an important part of the Twin Cities area, now it's gone. It'll take years to recover from this.
posted by Matt @ 11:20 PM
9 comments
9 Comments:
What happened there?
Your guess is as good as mine. I'm not sure anybody knows why or how it collapsed. The mayor and governor have told us that it was inspected for structural damage in 2005 and 2006. Sen. Coleman said (and it looks like most of the media have seemed to pick up on this) that it hadn't been inspected since 2004. Regardless, structural engineers weren't expecting any major repair of the steel beams supporting it until 2020.
There's been major road construction for the past two months or so going both ways on the bridge, reducing it to two lanes on each side. My best guess is that that may have had something to do with it. Right now, from what I know, everyone is at a loss as to what may have caused it. Questions that are probably best left unanswered for the time being.
I was trying to find a good pre-collapse picture of the bridge to try to get an idea. The video CNN is showing only shows one side, but it looks as if the "near" bank on that video was the point of collapse.
My first thought was water corrosion / erosion of a foundation somewhere but it would appear at least on the level of casual observation that the failure happened somewhere near where the support met the deck. This makes sense stress wise as thats the highest point stress, but it doesn't make much sense bridge wise.
Civil engineers tend to design stuff with a safety margin of about seven, which is why things like this happen so infrequently.
I seriously wonder if this was a terrorist attack. Homeland security was mighty quick to say there was no evidence, considering that some C4 placed under the water line on a support could have accomplished this easily and there would be no way to tell at this time.
It looks like some of the inspections done over the last couple of years have actually found some structural deficiences in the steel supports, giving it a rating of 4 out of 10 (i think), whatever that means. We have a democratic legislature and republican governor who have been in gridlock for years on how to best fund the maintenance of minnesota's infrastructure. We have brutally cold winters, and moderately (getting warmer and dryer every year) warm summers. You can't walk down your street anywhere in minneapolis during the summer without seeing some kind of road construction. I'm not sure if the funds for infrastructure were insufficient, but it wouldn't surprise me considering the fact that pawlenty was elected on the promise that he wouldn't under any circumstances raise taxes in the state.
It's definitely not an attack, although I must admit, that was the first thing that came to mind when I saw it. The roads are sheered off in a clean perpendicular line on the side that I live on... really strange. There were some reports of an explosion, but they're probably just referring to the force of the steel beams snapping in two.
Well thats the odd thing. Quick engineering lesson coming, so look out!
There are tons of different ways things can fail but for this purpose I'll limit it to three. Things can fail in tension, like what happens if you pull silly putty apart really fast...stretch a bit then bang! Or, things can fail from fatigue. The way fatigue works is something is bent over and over and over and eventually (usually at a surface imperfection) a crack will develop...eventually the crack moves through the material until you run out of enough area to support the stress..then snap! A third major way is shear, like if you pushed down so hard on the axle of your car that it just snapped clean from the wheel. Thats how bolts in bridges and things usually fail.
Now the concrete makes sense because its brittle and it doesn't support any of the structural load (weight) of the bridge -- it just sets on top.
But the fact that people heard a big bang tends to go more with what you said...a snapping or popping type failure, which is usually caused by overload. Thats the first type I mentioned.
Which isn't really consistent with bridges, because its been sitting there for 40 years with varying loads on it. I understand the thing with weather but for steel the range of -20 F to 110 F isn't that dramatic; and in actuality the type of failure it *appears* to be is more likely to occur during the winter, as a lot of steel alloys suffer from whats called a ductile to brittle transition around 0-32 F. That makes them less bendy and more likely to snap (like the Titanic).
I guess my point is that if it was shear, like bolts breaking, the thing seems to me would just kind of...fall to pieces, as if someone pulled a lynch pin. This looks more like several lynch pins were pulled at once to me.
But I'm not a civil engineer or anything...
Matt, you should read this.
NASA has made a mistake in their data and published a correction -- meaning that 1998 is no longer the hottest year on record. 1934 is.
In fact, only three of the top ten hottest years are even from the past ten years.
Let me know what you think.
Sorry man, I gotta stick with my climate scientist peeps again on this one. McIntyre has some legitimate points to make about the methodology of some of the collection of data in the study of anthropogenic global warming, but when you look at the bigger picture, it's all just white noise in the background.
This is an insignificant adjustment to the mean temp in the U.S., which geographically makes up a tiny fraction of the entire world. You're right, 1934 is now the warmest on record... in the United States. 2005 is still (or 1998, depending on what set of data you're looking at), the warmest on record globally. This isn't exactly blowing the lid off of the "global warming hoax".
McIntyre isn't a climate scientist. He is a rather accomplished mathematician however which gives him credibility. But this, and his other "major contributions" to global warming denial are unsubstantiated and have had little impact on the overall assertions of real climate scientists. I'm not a mathematician, and I'm not a climatologist... But I'll trust RealClimate over ClimateAudit anyday. Each has an agenda to push a certain point of view, but one has the advantage of expertise on its side.
1934 now beats out 1998 by .02 degrees celsius in the United States alone.... I say, BIG WHOOP. That's why it's called global warming.
Just for the record almost every climate paper published in the past 10 years references that very same GISS data. Its not a big whoop, its a HUGE one.
That's what they were using to calibrate their models. It would be as if someone suddenly found that every calculator or computer manufactured in the past fifteen years had a teensy weensy goofup that rounded all answers up .1%. Whoops! Billions of dollars!
But no big deal right, because what would a mathematician know about computers?
Wow, you make sooo much sense. You've awoken me from my climate science stupor. I NEVER thought of it that way. Thank you for being such a friggin genius... I don't know what I'd do without you kaggie. If only more problems with surface temperature data could be found... than global warming would just magically go away.
Evidence for global warming isn't entirely based on surface temperature data. Even if it was, finding a flaw in the data collection at ONE or TWO, or even (god forbid) THREE stations wouldn't throw off the mean enough to have any significant impact on the overall fundamental, and incredibly obvious conclusion that the planet is warming at a disturbing rate. Even your hero richard lindzen has admitted that things are getting hotter around here.
The Richard Lindzen who's pocketed $2,500 a day from big oil and coal. Who's travel is paid for by Western Fuels. Who's speeches are underwritten by OPEC. The Richard Lindzen who gets hosted by ExxonMobil at luxurious conferences and distributes his writings to oil-funded pundits everywhere. The Richard Lindzen who can't for the life of him get any of his current articles published in any peer-reviewed journal. Even HE admits there's warming.
You're fighting the wrong battle, grasping for straws... hanging on tooth and nail to your denial. You won't believe because you choose not to. Not because you objectively looked at and studied the issue. You labeled global warming science liberal propoganda a long time ago, making it permanently evil to you in your simple, black and white conservative world. Keep fighting, I like these arguments... they're the easiest to win. Find a better point to make next time though... something that actually affects the overall conclusions of climate science; make this more of a challenge.
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