I35W Bridge Collapsed in Minneapolis
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The bridge was found in a report structurally unstable for heavy traffic and trains at the same time. a jack hammer will cause no harm to the structure of the bridge.(unless your doing it on supports or something) ive been watching the news off and on all day and there are only 4 deaths so far with 79 people in the hospital. the sad part about it is they havent started diving yet do to the settling debris.
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Jackhammers, packed full of cars, AND a train underneath it could all cause quite a bit of vibration.
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atleast 40-50 is the early reports.
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tjamz;179162 wrote:
The jackhammer alone could not take down the bridge, this is 100% true, but IF the jackhammer where causing reverberation across the entire bridge at precisely the right frequency AND if the cars were traveling at the exact right speed to amplify/spread the vibration across the bridge there is about a 1 in a trillion chance that it could have AIDED in the falling of the bridgeok i had to say this... do you seriously just think up random shit. i jackhammer is not going to do shit. how does a car reverberate jackhammer movements?
they had some guy that is a safety inspector and he said it was prolly cracking and that it finally just gave way. he also said that the roadway had nothing to do with it's strenght so the work being performed had little effect on the collapse.
but i will leave the cause up in the air as i have no clue how it fell down.
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DrifterExtreme;179208 wrote:
ok i had to say this... do you seriously just think up random shit. i jackhammer is not going to do shit. how does a car reverberate jackhammer movements?they had some guy that is a safety inspector and he said it was prolly cracking and that it finally just gave way. he also said that the roadway had nothing to do with it's strenght so the work being performed had little effect on the collapse.
but i will leave the cause up in the air as i have no clue how it fell down.
To answer your questions one at a time here:
No, I do not think up random shit.
**IF **jackhammer is causing a slight ripple that is traveling at the same frequency as the cars, the cars would essentially push the wave taller and taller. I learned this basic principle in highschool physics.
I also have no way of proving/disproving my statements, hence the 1 in a trillion guesstimate.
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civic91;179214 wrote:
i dont know about bumper to bumper because there wasnt that many cars on the parts that didnt completly fell but they could have moved off idk. i just think that you would have seen more cars parked on the edge.... dude it was bumper to bumper, the rest of the cars are underneath the rubble.
Have you ever been in that construction zone during rush hour?
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http://www.in-forum.com/pdfs/bridges_opt.pdf
Report on the bridge in 2001.....
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tjamz;179219 wrote:
http://www.cnn.com/video/#/video/us/2007/08/02/vosli.mn.i35w.bridge.collapse.side.view.cnnvideo of it falling
That is crazy that it all came down at once so quickly. I figured someone had to have gotten video of it with traffic cams or something, but hadn't seen one yet.
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tjamz;179209 wrote:
To answer your questions one at a time here:No, I do not think up random shit.
**IF **jackhammer is causing a slight ripple that is traveling at the same frequency as the cars, the cars would essentially push the wave taller and taller. I learned this basic principle in highschool physics.
I also have no way of proving/disproving my statements, hence the 1 in a trillion guesstimate.
see the mythbusters episode? They were actually able to make an entire bridge vibrate with a fairly small weight however they were quick to note it's nowhere near remotely capable of knocking over a bridge.
The only theory I've heard yet that I'll be willing to buy this early is the possible seperation of an expansion joint.
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tjamz;179209 wrote:
To answer your questions one at a time here:No, I do not think up random shit.
**IF **jackhammer is causing a slight ripple that is traveling at the same frequency as the cars, the cars would essentially push the wave taller and taller. I learned this basic principle in highschool physics.
I also have no way of proving/disproving my statements, hence the 1 in a trillion guesstimate.
Then your high school physics should explain how that frequency could establish sympathetic vibration to "match and push the wave taller and taller' which must be required to.
The frequency of that jackhammer in that small of distortion area, even let us assume that there is 30 of them, chained hypothetically side to side, would fail to create that frequency require for the support to bend, look at the pictures it is due to one of the large pilers crippling.
What more of the issue is, for anyone who lives in the metro, please take a jump in the miss. river in comparison to the past 10 years, during the spring/summer season it is extremely volatile towards its northbound push, it is more then likely the failed support piler beneath that (Soot) was eroded, and thus it crippled.
This is a pure educated guess, and is not factual, however many expert PE and CE's are concurring to this, but will not be affirmed until maybe after 2 years of investigation.
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In reality its just that everything necessary for the bridge to collapse happened at the exact same time. For all we know it could be there was a crack in the support, the water had eroded away more soil or whatever around the pillar, the train going by caused vibration that somehow when combined with the cars overhead and the jackhammers all added up to create a single wave with a HUGE amplitude that helped destroy the rest of that already cracked support which led to the collapse. None of those alone could have brought it down but when they all added up at that single point in time it did the entire bridge in.
We will really never know, the best we can do is say that the DOT and whoever else's investigation will give us a very good guess as to what led to the failure.
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StangerBanger96;179269 wrote:
In reality its just that everything necessary for the bridge to collapse happened at the exact same time. For all we know it could be there was a crack in the support, the water had eroded away more soil or whatever around the pillar, the train going by caused vibration that somehow when combined with the cars overhead and the jackhammers all added up to create a single wave with a HUGE amplitude that helped destroy the rest of that already cracked support which led to the collapse. None of those alone could have brought it down but when they all added up at that single point in time it did the entire bridge in.We will really never know, the best we can do is say that the DOT and whoever else's investigation will give us a very good guess as to what led to the failure.
I agree with you 100%, I just don't agree that jackhammer(s) could cause anything to be remotely related to it though however, after my own research, and after consulting with 2 PE's (Certified and work for a firm located in the same building)
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