35W bridge in minneapolis collapses

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A bridge over the Mississippi River in Minnesota has collapsed, resulting in cars falling into the water. Initial reports indicate that several vehicles, including a school bus, were on the bridge at the time. Recovery efforts have been complicated by darkness, and there are concerns about fatalities, with reports suggesting a death toll of at least nine and many others missing. The bridge was undergoing repairs and had previously been classified as "structurally deficient," raising questions about its safety despite a recent inspection. Discussions among forum participants highlight the potential causes of the collapse, including possible material fatigue and the impact of construction work nearby. The media coverage has drawn criticism for sensationalism, with calls for more responsible reporting on the incident.
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"A bridge over the Mississippi River in Minnesota has collapsed, sending cars into the water, The Associated Press reports" - CNN. Hope everyone here is ok! My sister and brother-in-law take it every day, but they phoned us ok.
 
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Good grief.

Do you have a link to the story?
 
It's on cnn.com and every tv news station
 
There's a little more at Yahoo:

http://news.yahoo.com/s/ap/minnesota_bridge_collapse

I hope no one was killed.
 
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Mallignamius said:
There's a little more at Yahoo:

http://news.yahoo.com/s/ap/minnesota_bridge_collapse

I hope no one was killed.

Reports of cars under the collapsed bridge, that doesn't look good
 
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Thats very shocking to see. Your right it dosen't look good for some, but was glad to hear the school bus made it.
 
I have a friend in Minneapolis that takes that bridge.
 
Yeah, I saw this on the news, I hope there aren't too many serious or fatal injuries. I wonder what caused it.
 
Wow, those people were in their car and fell 64 feet into the water. Thats like driving into a brick wall at 100mph.

Thats a bad way to crash because the road literally fell from under the car. A car is not designed for that kind of an impact.
 
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  • #10
"Recovery efforts have been halted because of darkness"

CNN says "Recovery efforts have been halted because of darkness". Are they serious? Night light at football games can make the whole field look like it was noon on a sunny day. It's my understanding that there might still be dead people in the water. Terrible tragedy.
 
  • #11
On the bbc, they were reporting 50 cars in the water -- there's sure to be people killed :frown:

Also, the story of a school bus, with 60 kids on board, which just stopped before/on the gap (http://www.bbc.co.uk/mediaselector/check/player/nol/newsid_6920000/newsid_6927100?redirect=6927160.stm&news=1&bbwm=1&bbram=1&nbwm=1&nbram=1&asb=1)

http://img381.imageshack.us/img381/4146/44034277bridgecollapse4ji4.jpg http://img381.imageshack.us/img381/7104/44034283slope220apsl4.jpg

http://news.bbc.co.uk/1/hi/world/americas/6927113.stm (e2a: http://photos.denverpost.com/galleries/newsgallery.html#id=1351&num=1)

:frown:
 
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  • #12
Said on the radio an hour ago that the death toll is 7. Looks like a lot of people survived the impact.
 
  • #13
They just mentioned 9 people were killed, and 20 people are still missing. They mentioned that the effort this morning has changed from one of rescue to one of corpse recovery.

They are saying that the death toll is expected to rise later on today.
 
  • #14
Are they suspecting terrorism? I mean, the bridge was given the OK about 3 years ago after an inspection. It just can't fall, right?
 
  • #15
No one mentioned an explosion before it collapsed, just that it suddenly gave way.

Terrorism has been ruled out, it said that just as I was typing this. :smile:
 
  • #16
Schrodinger's Dog said:
No one mentioned an explosion before it collapsed, just that it suddenly gave way.

Terrorism has been ruled out, it said that just as I was typing this. :smile:
When I first heard it on the radio this morning, it sounded like an earthquake -- the people were saying it started shaking then they went into free-fall.
 
  • #17
Earthquake? Minneapolis? The shaking was probably just the bridge giving away.
 
  • #18
According to the news reports the bridge was under repair at the time.
 
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  • #19
cyrusabdollahi said:
Wow, those people were in their car and fell 64 feet into the water. Thats like driving into a brick wall at 100mph.
Just to put a little perspective on this, they could not have fallen at free fall velocities. It's a collapsing bridge, not a disappearing bridge.
 
  • #20
ranger said:
Earthquake? Minneapolis? The shaking was probably just the bridge giving away.
Yeah -- I don't know that part of the US very well (apart from the airport), but thought it stange.

Like you say, the bumps people were reporting were probably the bridge giving in stages.

bbc: why?
 
  • #21
BEFORE:
i35wmiss02.jpg
AFTER:
ekjl.jpg
Who knows what caused it... the bridge was undergoing resurfacing and other 'minor' construction. Not sure what that means, but it might have had something to do with it. A failure of just one of those truss connections could cause the whole thing to come down.

They said it was bumper to bumper traffic just before the collapse, but it was mostly small cars. Bridges are designed to carry fully loaded tractor trailers bumper to bumper which is considered the worst case loading. I don't think this was the highest load the bridge had seen in it's 40 year lifetime. It must have been either some kind of material failure (corrosion, fatigue) or something happened with the construction that was going on.

Lower maintenance is a big reason that a lot of bridges like this are made of concrete now instead of steel (see adjacent bridge).
 
  • #22
  • #23
That video on cnn's website is quite a mouthful to grasp. Its just unbelievable to see steel and concrete (?) in such a state.
 
  • #24
My friend in Minneapolis just wrote me, he had this to say.

They installed an automatic de-icing system a few years ago and that is corrosive material (no one mentioned this) and it's been quite hot, that could have placed unusual expansion stresses in the steel truss structure. The failure happened at one point and the rest of the collapse was cascade or chain reaction. It's clear it was on the west (south end) bank side and from my inexpert opinion looking at the wreckage from the TV videos, the down stream side failed first and the bridge torqued and collapsed.
 
  • #25
ranger said:
Are they suspecting terrorism? I mean, the bridge was given the OK about 3 years ago after an inspection. It just can't fall, right?

Sure it can, it just did. 3 Years ago is a LONG time ago. But they said on the news it was inspected last in 06, and probably its next inspection for 07 was coming around sometime soon. I am not sure where you heard 3 years ago from.

Whoever the engineer is that signed off on the bridge, its going to be his ass.
 
  • #26
DaveC426913 said:
Just to put a little perspective on this, they could not have fallen at free fall velocities. It's a collapsing bridge, not a disappearing bridge.
As we know from debunking 9/11 conspiracy theories, structural failure is generally an all-or nothing thing. When the structural members fail, the bridge would have essentially dropped in freefall. Even when the failure is buckling instead of breaking (this one probably had both), the ability of the members to hold up the weight/resist the fall drops by many orders of magnitude.
 
  • #27
ranger said:
Are they suspecting terrorism? I mean, the bridge was given the OK about 3 years ago after an inspection. It just can't fall, right?
Not a cheery throught, but this bridge was on a federal list of "structurally deficient" bridges...a long list:
He says investigators are sure to look into whether work crews or passing trains caused excessive vibrations on the steel-truss span, which was deemed "structurally deficient" on a federal list of bridges.

"A structurally deficient bridge might be one not adequate for the traffic it takes, but not necessarily dangerous," Burnett tells the paper. "But a lot of structurally deficient bridges are dangerous."

The feds have information about deficient bridges. So does the group that represents civil engineers. It says: As of 2005, 156,335 of the nation's 595,363 bridges, or 26.3%, were structurally deficient or functionally obsolete, as compared to 34.6% of all bridges in 1992.
http://blogs.usatoday.com/ondeadline/2007/08/expert-points-t.html
 
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  • #28
Schrodinger's Dog said:
Terrorism has been ruled out, it said that just as I was typing this. :smile:

Yeah, in a country of paranoia that's the first concern. :rolleyes:

It's insane though. The infracture issue is happening all over North America. No politician wants to take anything seriously, so maybe we will an INFRAC Concert like Earth and that 8 convert.
 
  • #29
I like how the newspeople are asking, "well, they were jackhammering near the bridge, do you think that might have been a cause?"

Just ONCE, Id like to see someone say, "No,...its your bullsh!t reporting that caused it to fall". They have animations of the bridge falling, actual footage. Probably a bridge falling expert to comment on it. Of course, "terrorism was ruled out". Really, you think so?

The people on the news are idiots. One guy on cnn.com was on the bridge and he was talking about it. The reporter said "wow, you're very calm, Id be panic stricken"...yeah were all a bunch of idiots that run around like our heads chopped off everytime something happens. GIVE ME A BREAK. Then he said "I guess that calm comes over you when you have a near death experience".
So the guy just looked at him, gave a little laugh and said "Yeahhh...I guess so".

<smacks myself in the forehead>

A damn bridge fell. Its not that hard to comprehend if you have a brain in your head. This kind of media hype gets under my skin.

[/rant]
 
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  • #30
Crappy engineers, crappy maintenance.
 
  • #31
russ_watters said:
As we know from debunking 9/11 conspiracy theories, structural failure is generally an all-or nothing thing. When the structural members fail, the bridge would have essentially dropped in freefall. Even when the failure is buckling instead of breaking (this one probably had both), the ability of the members to hold up the weight/resist the fall drops by many orders of magnitude.

Isn't there any resistance from the connecting roads? I was just wondering if it would take slightly longer to begin a drop because of the steel beams (or stiffening girders?) running horizontally underneath, connected to the ends of the bridge and the anchorage blocks or abutments. If so, perhaps that would explain the "earthquake" descriptions, that the bridge has to pull away from the ends?
 
  • #32
cyrusabdollahi said:
...Probably a bridge falling expert to comment on it. ...[/rant]

They did have a bridge expert on the news this morning to explain what might have caused the collapse. He was a reporter's worst nightmare. The reporter had to keep pushing him for an answer to why the bridge fell.

The short version of his answer (stripped of the technical info incomprehensible to the average viewer) was, "How could anyone possibly know until they get a look at the bridge?"

You could see it in her eyes: "You have to know because some stage technician led you up here to a chair in front of me! Don't you realize you're killing me right here on the air?!" :smile:
 
  • #33
This is nothing but more of the same, media hype. A bridge fell. Report it correctly. Tell me what happened, how many people died and then move on. Then follow up a month later with a report explaining why it fell. But when you have all day news programs with nothing to talk about, they report the same crap for 12 straight hours on how the bridge fell. Yes, there was a school bus on the bridge......and? So what? Did everyone in the bus die? No. :confused: Is this good news reporting? No.


Quick, make an animation of the bridge falling, because were too stupid to think in our minds how a bridge falls. They even put all the cars on the bridge (bus included) as it fell in the animation. I wish one day a news reporter asked me a question live on the air. I'd call him a moron to his face.
 
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  • #34
cyrusabdollahi said:
This is nothing but more of the same, media hype. A bridge fell. Report it correctly. Tell me what happened, how many people died and then move on. Then follow up a month later with a report explaining why it fell. But when you have all day news programs with nothing to talk about, they report the same crap for 12 straight hours on how the bridge fell. Yes, there was a school bus on the bridge......and? So what? Did everyone in the bus die? No. :confused: Is this good news reporting? No.

Welcome to the 21st century, bro. Sensationalism in its most pure form ever.

cyrusabdollahi said:
Quick, make an animation of the bridge falling, because were too stupid to think in our minds how a bridge falls. They even put all the cars on the bridge (bus included) as it fell in the animation.

:smile: :smile:
 
  • #36
cyrusabdollahi said:
Excuse me, I am going to go hide in my closet now with my duct tape.

Short off-topic comment: at some point, you'll have to get out of the closet, though. :-p
 
  • #38
Mallignamius said:
Isn't there any resistance from the connecting roads? I was just wondering if it would take slightly longer to begin a drop because of the steel beams (or stiffening girders?) running horizontally underneath, connected to the ends of the bridge and the anchorage blocks or abutments. If so, perhaps that would explain the "earthquake" descriptions, that the bridge has to pull away from the ends?
Yeah, and of course, parts of the roads never detatched, so those sections only fell at one end. So perhaps the outer third on each side was slowed by that. But the center of the span would have fallen at near freefall acceleration. Also, though, supporting a falling object from one side makes half of it fall slower than g, but the other half faster than g because the center of gravity is trying to accelerate at g. That's why smokestacks that are demolished by toppling them break while they are falling - the different accelerations cause them to bend.
 
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  • #39
(I only a few minutes ago saw the animation. I didn't know it broke up.)

So then could a connected end quickly snap upwards (following a detachment)? I suppose under such circumstances, cars could go flying if they're on those sections.
 
  • #40
Not according to the animation! LOL
 
  • #41
They have video of the actual collapse online now...
 
  • #42
Yea, you should watch the video on cnn's website instead of those crappy animations.

As I was reading the morning papers, they were saying that the bring had an inspection in 1990. To sum it up, it was given "structurally deficient".
http://www.courant.com/news/nationworld/nation/wire/sns-ap-bridge-collapse,0,1159498.story?coll=hc_features_outdoors_util
 
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  • #43
cyrusabdollahi said:
I like how the newspeople are asking, "well, they were jackhammering near the bridge, do you think that might have been a cause?"

Actually the jackhammering could have played a part in the collapse. If there were already corrosion problems and fatigue cracking in the welds, it is very possible that the vibration from the jackhammer amplified the problem and was the immediate cause of a truss connection failure... which in turn caused the rest of the bridge to come down.
 
  • #44
A jackhammer is not really going to put a stead sinusoidal vibration on the bridge at exactly the resonant frequency of the structure. Could it play a role, possibly. The point is, it was a stupid question/statement for the reporter to make. I have seen a few clips of reportes saying stuff without knowing what there talking about, such as: "I know in a suspension bridge that if one section fails the whole bridge fails" and the expert told him, "well, that's not true". Quite sad.

Bumper to bumper traffic twice a day for 40 years of loading and unloading the bridge will fatigue crack it appart though.
 
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  • #45
The coverage makes me believe everyone should be forced to play armadillo run, or a similar game, in school at some point. It's amazing how small the difference between all-ok and near total collapse is.
 
  • #46
cyrusabdollahi said:
A jackhammer is not really going to put a stead sinusoidal vibration on the bridge at exactly the resonant frequency of the structure.

You don't have to have steady vibration at the resonant frequency of the truss to cause fatigue stress in the connections. I'm a licensed structural engineer by the way.
 
  • #47
Interesting, you think jackhammers would have an effect on such a large structure? Personally, I find it rather hard to believe. I would expect the vibrations of the cars and tractors trailer going up and down the bridge to wash out the noise from a jack hammer.
 
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  • #48
cyrusabdollahi said:
Interesting, you think jackhammers would have an effect on such a large structure? Personally, I find it rather hard to believe. I would expect the vibrations of the cars and tractors trailer going up and down the bridge to wash out the noise from a jack hammer.

I'm not saying the jackhammer caused the collapse, but it could have contributed. I think corrosion and fatigue were the main problems... but since only 2 of the 6 lanes were open at the time of collapse, something else must have played a part. Otherwise it would have collapsed on a day when it was more heavily loaded (all 6 lanes full).
 
  • #49
Cheif, you should get a copy of the New Yorker, June 25, 2007, pg. 70. They have a nice article on Cecil Balmond.

He is one of the top structural engineers in the world right now.
 

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