I35 bridge collapse Minnesota | Why did it happen and how could it have been avoided?

On August 1, 2007 at 6:05 pm the I35 bridge in Minneapolis, Minnesota collapsed. This video explains why the bridge collapsed. It video discusses the age of the bridge and the amount of deterioration and bridge inspection ratings. Finally, the design is discussed. The bridge was not designed correctly and this contributed to the failure. A video of the failure is also shown that highlights tracks how the failure occurs at the under designed Node U10. At the time of failure the bridge was under construction and a load of 580,000 lbs was placed in a 12’ x 115’ area. This is a large load for a small area. Furthermore, this load happened to be placed right at the under designed spot.
The video goes on to discuss ways that the failure could have been avoided and it completes by highlighting changes that are needed to keep failures like this from happening in the future.
A detailed report can be found here: www.ntsb.gov/investigations/A...
A video of the failure can be found here: • Video
My website is: www.tylerley.com
If you would like to donate to my channel please visit www.tylerley.com/giving

[@jksaw]

Government never does anything until a major disaster occurs.

[@trackerrrr]

They sure got a new bridge up quick though after this didn't they?

[@jacqueslefave4296]

IME, most contractors don't give a sh*t.

[@sln7839]

So important to inspect and maintain bridges regularly. Inspection should be serious and not just another formality.

[@dudeplayinadudeplayinadude]

Thank you for this video. My friend was on this bridge when it collapsed and was hurt severely.

[@MCCORMICK10202236]

I worked on that bridge and knew before that bridge went down. First of all. When that bridge was designed and built, it was for a four lane, with a lighter deck. Then for some reason it was made into a six lane with a larger deck and heavier barriers. Look at the history of the bridge first. Also DOT was warned by contractors that the bridge was being overloaded with the bigger deck and heavier traffic. That causes accelerated fitige. And during that time of the incident DOT told the contractor to put all that material on the bridge. Funny how the DOT wasn't held accountable?!! That bridge should have replaced back in the 80's. But mndot and the federal are always trying to run on a budget!

[@josephkane825]

MCCORMICK If you read the investigation report, there was a question as to whether the contractor had tacit permission to pile the cement , gravel and sand on the bridge deck as a time saving device. There was clearly no prohibition against it. Furthermore, the investigators say that the trucks were of bridge formula legal load. So, even if they did not have permission to dump the loads on the deck, they could have parked legal load trucks on the bridge with an even greater weight! In fact that number of trucks or perhaps a far greater number of completely legal truck loads could have been driving on the bridge with the additional vectors of speed and surge from acceleration and traffic slow down, creating an even greater total load. I cannot see this as an issue of blame. The bridge was not designed for the loads that it was in daily use for twenty years after it was designed.

[@MorrisDugan]

There has been something fishy about MNDOT in general for a long time, and nobody seems to be interested in investigating. Lots of bad but expensive road design, lots of tearing up poorer neighborhoods with road projects...

[@jimmadson]

I agree. I have lived in Minneapolis my entire adult life and I remember the expansion from 4 to 6 lanes. People say the gussets were underdesigned. I think they were probably fine when it was 4 lanes but they didn't reinforce them to hold the new weight of the lanes and cars. Also, I drove over the bridge during the reconstruction, you had to go very slow and I remember seeing large holes in the deck, about the size of a queen sized bed that had been completely cut out and you could see river below. I read a few years ago the the strength of the bridge came mostly from the strength of the deck. I would guess if you started removing large sections of it, it would make it weaker. That with all the construction equipment (which they left all day and overnight for months), the unreinforced gussets, deterioration, and all the jack hammering to remove portions of the deck make we wonder why anyone thought it wouldn't collapse.

[@MorrisDugan]

Minnesota has a relatively "clean" government, but I have to wonder about the DOT, and quite a bit more about the MPCA (Pollution Control Agency).

[@agentx7138]

This a bad excuse. I will not do things at work if I dont believe it's safe even if the boss insists that it is ok.

[@morg52]

I was running erands in the area of the bridge about an hour before it collapsed. I was going to take the bridge northward over the river but though better of it because I figured the traffic would be backed up. I took tenth ave instead. Kind of weird how choices can have consequences. Anyway, Cemstone got the contract to build the new bridge and they poured it out of the Mpls plant. I'm out of the Midway-Saint Paul side of town. They had a day where they got way behind because of dispatch screw ups and I got to haul two ten yard loads to the new bridge. Still have the 35W bridge safety briefing sticker on my hardhat.

[@grizzlygrizzle]

In another case of disaster avoidance, the Schoharie Creek bridge in NY collapsed right around the time I would have been going over it to get home for an appointment, were it not for a screaming argument I had with my girlfriend that led me to leave her early and drive through the night prior to the collapse. She was a very difficult woman, and the relationship didn't last long, but her bad personality may have saved my life. That was in 1987.

[@TylerLey]

Those are both really cool stories!

[@markfryer9880]

Yes the sliding doors of fate can save you or kill you. I avoided being involved in the Russell St Police Station bombing Melbourne Australia in 1986 simply by deciding to go home to nap before going out that night. The place where I usually parked my car was in the shrapnel zone and and I could have been walking towards the intersection near the station at the time the car bomb went off. I have also narrowly avoided a number of car accidents by less than one minute, one of which was a double fatality. I have also had a mobile crane fail and drop its load within metres of me. You need eyes everywhere and to listen to that little voice in your head as well as the hairs on the back of your neck.

[@danielfronc4304]

Mark Fryer Whether or not you believe in a God, you may well have had someone looking out for you. Also, with your stated history you may be being stalked. Thirty years ago I did not believe in an evil existing in our world at different levels but from what I have seen and, like you, experienced in the intervening decades I now know that there is indeed an evil that exists in our world, either courting some, trying to harm us and working against the good efforts of my God. And no, I am not a born again, holy roller Christian. I'm just an "ordinary Joe" who works in the healthcare field. I just know what I have seen in life, the good and the bad that has happened. Watch your six my friend.

[@ulcus...]

My dad was going home from work and decided not to go on i-35w because of the traffic

[@patriot9455]

I am a retired long haul produce driver. My "route" ran from the valleys of California to the cities of the east coast. every time I came to Atlanta, I went under a runway. When I went through Louisiana, I tried to avoid avoid I-10 through New Orleans. My career was based on having safe roads to travel. I hope you help the students you teach understand deeply that their contribution is of life and death importance, as much as my job was to deliver fresh, safe vegetables and fruits on time.

[@bbeen40]

I used to hate sitting on that bridge in traffic. You could feel it shaking and swaying. MNDOT is crooked as hell. They had the same problem with a Bridge in St. Paul, they replaced that pretty fast after this. The new 494 bridge started falling down before it was even finished, so they had to tear it back down and rebuild it, again, with the SAME crooked contractor. Then they built a new bridge near Stillwater and when the two ends met in the middle, they didn't line up. They jimmy-rigged it so look forward to more of these in the Twin Cities in the future.

[@maddeusdoggeus1]

Tyler you are a breath fresh air. Wish we had people like you in politics. Thanks for taking the time to teach and inform.

[@stevewaclo167]

As I review the comments, I’m pleased to discover contributions from many educated and motivated people. 👍👍👍 Tyler, this channel is a valuable resource and deserves much more attention! Best

[@lowercherty]

Right after Minnesota started a major bridge inspection program and found two other major bridges that were shut down immediately and replaced. Others have had ongoing major structural work done since.

[@paranoidandschizophrenic2813]

I wonder how everything is going now

[@calcrappie8507]

I remember fishing under that bridge around 1970 as a young teenager. Looking up I would see pigeon droppings, rust forming and dripping even when it wasn't raining. I wasn't impressed. It didn't look very solid to me and it was only 3 years old at that point. The underside of the bridge kind of reminded me of that movie from the mid 70s with the bridge collapse called Cassandra Crossing. Just imagine how much salt was dumped on the roadbed over the 40 winters before it collapsed.

[@rogerfurer2273]

Good info! I remember that disaster. Always wondered about the details. Thank you.

[@jr3474]

Dr. Ley.. I really like your honest approach. Any words about the FIU emblematic bridge that collpased in Florida in 2018?

[@tscott6843]

Stumbled across your channel tonight. Awesome. Thank you.

[@hchenfullerton7683]

Learning something new everyday....with much appreciation!

[@TazzeOptical]

1:39 "Engineers do not allow the traveling public to be on bridges that are unsafe" 145 people would probably disagree with that statement, 13 probably would if they could

[@TroyParaiso]

💯

[@johnb9394]

IF the bridge failed because of node 10 then why did the other end on the bridge go down first?

[@johnb9394]

I think the video is turned around or you pointed out the wrong end or something. Other videos I have watched showed Node 10 on the failing end that went down first

[@ilovecops5499]

Evewr hear of somalis? Thinks abioutit!

[@KD_Smoove]

Bro Node 10 was the weak one we saw the pictures, watch the video nod10 is where it starts bending and since the majority of the bridge was behind it it fell, it weigh more... but yeah you can literally see where its bending and why ts fell

[@drewandfrank]

Great video! Tragic, tragic. I believe recent inspections of bridges in the US indicate that this type of tragedy will reoccur unless major repairs are made.

[@muizerabdusalam4587]

Thank you Sir for the great information regarding the failure of the bridge. I really like your channel. Thumbs up! 👍👍👍

[@julianm8215]

Great video. I was wondering if you could do a review of the chirajara bridge failure in Colombia last year?

[@julianm8215]

@dothemathright 1111 did you read about the other one that looks like an acordeón? (Puente hisgaura)

[@hull39]

The Schoharie Creek bridge collapse on the New York State Thruway (approx. 1982?) would be another interesting one to look at.

[@hamzamMR]

great as usual Dr tyler !!!

[@TylerLey]

Thanks Hamza! It is nice to see your comment so quickly on my videos.

[@hamzamMR]

thank you for uploading such high quality videos !!!

[@victorcharlie6384]

This is a excellent video.

[@TylerLey]

Thanks Victor! I tried to keep is to the point. Thanks again for the comment and advice.

[@gregg4164]

No not really. Someone got their facts mixed up or where mis informed.

[@Waterman-wv2jx]

You just described the FIU bridge collapse problems to a T. Yes, other issues there, but you nail it.

[@sportsmediaamerica]

Well done. Important stuff. Thanks.

[@TylerLey]

Thanks!

[@jtveg]

Great assessment. Thanks for sharing. 😉👌🏼

[@uendarkarplips7263]

I drove over that bridge hundreds of times. That was a scary day.

[@sln7839]

Superb analysis.

[@windaddiction]

Just found your channel (looking for info on concrete for school) it is awesome.

[@patrickp6775]

Again, great video.

[@TylerLey]

Thank you!

[@isaackimber5280]

Hi Tyler, concrete and asphalt roads which ones last longer and which one is less expensive?

[@TylerLey]

Isaac - Concrete is typically more expensive and should last a lot longer than asphalt if done correctly. If you look at the cost over a long period of time then concrete usually wins.

[@prodprod]

This seems to be a pattern that repeats constantly. A small repair early can prevent a massive disaster later --- but it's put off because it's just a little expensive, a little inconvenient, a low priority -- and it's put off and put off and put off -- until it's too late.

[@mfw6020]

Another great video.

[@ranggagautama3953]

nice analysis sir...

[@stevec8861]

Nice video teaching, but I was surprised by your emphasis on maintenance/repair near end, when bridge was doomed from get-go (needed a major retrofit of the gusset plates, not maintenance/repair). I remember the post collapse investigative finding you report here that the gusset plates were supposed to be an 1 thick, which came out long after the drive-by news media blamed neglect, which is unfortunately what stuck in most people's minds as root cause. Is there any chance the steel fabricator supplied two half inch gusset plates for each side of every joint (for a total of 1 inch on each side) but only one 1/2 inch gusset plate was installed on each side by mistake? I ask because it's hard for me to believe gusset plates not meeting design specs weren't caught before leaving the fabrication shop or when received on site, but I'm not a steel structure engineer and don't know if two half inch gusset plates stacked on each side of joint are equivalent to a 1 inch gusset plate on each side.

[@kdash3215]

Apparently the i80 W bridge in Illinois over the Des Plaines River just got rated 6/100. I remember driving over it thinking how damn rough it was. Over 50K cars a day

[@ndenise3460]

Looking at the bent gussets, i am surprised a quick fix wasn't some angle iron tied inon the diagonals of the gussets weren't installed until they could follow up with further engineering

[@nononsenseBennett]

Excellent review of the facts

[@TylerLey]

Thank you!!!

[@ScooterFXRS]

Another fun fact: They are using lead [Pb] plates as a buffer, as I understood it, however lead and alkalis do not go well together. Lead stands up great to acids but alkalis, AKA concrete, No. So unless they designed the bridges with that in mind, the lead becoming inorganic lead oxide powder which will buffer nothing.

[@MissJami]

Still think you're the best thing since sliced bread. Love your work as much as Feynman's (high compliment, Tyler).

[@TylerLey]

Thanks Jami! I am a big Feynam fan as well. I really appreciate the kind words.

[@TylerLey]

Feynman may show up in a video next week!!!

[@MissJami]

His comparison of hydrogen and water to people at a party is inspired. . You have that same ability...the ability to discuss something in terms of the familiar. (Cookies and Concrete). Thank you.

[@kenactofkindness4017]

as inspector and owner of 2 labs , sent my feelers out, talk to those on site, how bridge seized silent , no flex, talk to guy who cut wholes in the deck, also those who found out why plans for the bridge disappeared ..... tip of ice berg :) happy to be reitred amen

[@masmediamnt]

Tyler would you like to do a video like this about the collapse of the bridge of Genoa by ING. Morandi? I hear that creep has something to do about it, have you any thoughts? Take cake concrete Master

[@TylerLey]

Nicolas - Thanks for the message and nice words. I don't know a lot about the failure. I will look into it.

[@DuncanMaguire]

i have an exam in a weeks time and this collapse was on one of the previous papers, thanks :)

[@glennfelpel9785]

Would you consider checking into the failure of the bridge in Miami, FL. You are a concrete guy. And that was a very interesting case. I had never heard of a concrete truss before that failure. But looking at the preliminary sketches they had, not much was said about how loads would be transferred through the joints. What would be gusset plates in a steel application. Would like to see you look into that one! You are good at explaining the details.

[@sergeyshubin6679]

nice explanation!

[@TylerLey]

Thank you so much!

[@hasanshirazi9535]

If the bridge functioned for 50 years and collapsed due to extraordinary load placed on a small area then it cannot be attributed to design fault. Which designer in his right mind would design a bridge for this kind of misuse?

[@TylerLey]

Hasan, I agree that this was an overload case and it is not reasonable to totally blame the design. However, the gusset plates were undersized for the design loads. If they were the right size then the bridge probably would not have collapsed.

[@ajb7990]

They new it was going to fall in 1994

[@jdrissel]

I think this is the clearest explanation of what happened on the I-35 bridge. When I was about 18, I made a formal complaint about a bridge in Dallas County that crossed the Trinity River and it's very wide floodplain. If my memory serves, I came across it while using a map book to try to route myself around the worst rush hour in memory with the minimum of stops since my old truck had no AC. By the time I got to that bridge it was hard dark. There were no lights. The bridge jumped up and down, leaned this way and that. It was terrifying. I went back to look at it the next day. There were places where the pillars were crooked to the naked eye. When driving on it, some spans were more than a foot out of level from one end to the other. One span even rocked if you can imagine that. I was told it would be 3 to 6 months before an engineer's report would be made & a copy would be sent to me. About 2 weeks later that bridge was closed. Part of it collapsed in a flood about 4 months later. The "formal report" I received just said the bridge was "unsafe and essentially unrepairable". This seems to have all been "pre-internet". I can't even find a picture of the old bridge and there is now a huge park where the bridge once stood. You might be able to find it in bridge documents though. It connected Shady Grove Road in Irving TX to somewhere in the city of Dallas. It still amazes me that it was allowed to get to that state.

[@jdrissel]

@Jimmy De'Souza When I made the report the people in the office did not even know where the bridge was. When I showed them a map of it, it was not in their system. I do not think it had been inspected since that office had opened back in the 50's. If a bridge more than 1000' long and crossing the largest waterway in the county can be missed for 30+ years, how many small bridges that do not cross anything of note are being missed by the inspection program? It's a scary thought, but fortunately small things tend to be stronger and less prone to sudden failure.

[@MorrisDugan]

@@jdrissel That's why it's good to report those things. Even though it seems obvious that there's a serious problem, that problem might not be noted anywhere where it could make a difference - until you report it.

[@sureshtripathi9178]

You should also metion importance of Monitoring for the bridge

[@EddieVBlueIsland]

One more thing most people and even engineers missed - quite evident on the Wikipedia images of the buckled gusset plates are the numeros strain gauges attached to the adjcent beams - load monitors? Some technician or engineer reveiwing those images should have noticed the buckled plate and wonder why no strain gauge rosette was placed at the most obvious point of strain?

[@1425363878]

I'm so happy I found this channel, lol. Don't even know why.

[@TylerLey]

Thanks for watching!

[@markhottman2652]

Some things over looked in your video; 01) AASHTO 02) Operation & Maintenance If you don’t know what these items are you don’t know how critical bridges are in our Infrastructure

[@danielfronc4304]

Everyone who enjoyed this, go watch Tyler's presentation "Citicorp Center | NYC Skyscraper...". When it was finished and I saw it's design I could not at all not only understand how its design was approved but more importantly understand how such a huge structure could stand on five "peg-legs", or for that matter for how long. This is another of your excellent presentations Tyler, and as I tell my teenagers so that they may properly appreciate my compliments, I don't give false praise. I like the trouble you go to to show all aspects and reasons for such disasters, presented in the vernacular (average man's language) to be best understood and especially the video and diagrams you present. My father was an excellent mechanical engineer (Deputy Director, Naval Sea Systems Command, Bureau of Weapons - the highest such post a civilian in the U.S. Navy could hold) and while I was always interested in mechanics, creating things and working with my hands he passively reinforced and fostered it so that I entered a healthcare field which deals in micro-mechanical engineering. I had the grades and accomplishments to go to medical school but rather chose another similar path. Needless to say, a well earned "Thumbs Up"!

[@TylerLey]

Thank you so much Daniel for your praise and for your story. I love learning more about my viewers.

[@MorrisDugan]

Several years before the collapse, I had lived for many years in a part of Minneapolis where I would cross that bridge almost every day.

[@TylerLey]

Thanks for sharing! I grew up in Oklahoma City and I went by the Murray Federal Building about once a week. It is startling when a traumatic event happens in a place that we are familiar with.

[@bhatkat]

Here there now, remember I was watching the Simpsons when my ex called, got down there on my bike with my camera, got lots of pics of dazed college kids taking it in. Our pole barn outstate was built with plywood gusset plates. They were failing. Got pics of the nails pulling out before I beefed em up, never mentioned it to my dad, he never brought it up.

[@StarlinGrimes]

This is inspiring

[@gregg4164]

What we need is for you to go back and look at the video again and you will clearly see, the bridge failed on the other end first . Not where the bulk material was being stock piled.

[@darkaheart]

I don’t get it. If U10 failed why is it that the right side of the bridge collapsed and then it brings everything down with it? 3:49 - 4:25 I think the right side of the bridge failed due to the load and then it over stress U10, bending it even more. Someone correct me.

[@joshuasmith1215]

Looks like the original failure was the opposite side of what you circled in the video because it went down first...so how do you explain your explanation?

[@aeb1barfo]

One other consideration: The larger deck was made of pre-stressed concrete. That means that you had iron rebar embedded into the deck construction. this is a bit of a cheat, because pre-stressed concrete deck is only suitable for temperate climates.

[@rogerfroud300]

What did that extra massive load added by the contractors consist of?

[@jackandblaze5956]

Paving material and heavy equipment

[@ingenesist]

Tyler - I love your channel. Engineers need to become activists. I am the founder and Chief Engineer at the Integrated Engineering Blockchain Consortium. We are working on a new class of money that stores value in infrastructure (rather than gold, oil, or debt). This is our plan for funding engineering works. Let me know if these issues ever reach your radar screen and we'll discuss further. All the best to you and thanks for the great work. Dan

[@coldlama1909]

I remember when that happened I was sitting in my house in minisota and the TV just randomly turned to the news channel and I saw lots of dead people and cars and just lots of mayhem

[@2mj]

Tyler repeatedly says in the video the bridge was 50 years old, but it was 40 years old. That makes the line on the NACE graph at 1 minute into the video wrong, and the age + risk stats are off too.

[@TylerLey]

Your right. It was 40 y old. The stats are off a little but that again reinforces the bridge was not too old.

[@kib2675]

I have never seen a local politician getting into the media for good maintenance of road, tunnels and bridges. They only do that when they open something new. We need to vote for politician who promise to do nothing, and who will let the local engineering departments do their job.

[@FOBob-sr1fd]

I 80 bridge in Joliet. Very bad shape and no repair yet. Avoid that bridge.

[@grassfarmer42]

Aren't they working on it now?

[@ssmith2019]

'Nother gud viddy Tyler ! And Yeah let's fix some roads and bridges !

[@TylerLey]

Thanks! Let's do this!

[@Chepecafeteria]

For a second i got scared because I live in Dallas and thought that haf happened here in Dallas lol

[@josephkane825]

Tyler I liked this video. I did not like your Toyota Corolla comparison. It was lame. It would have been better to describe what the estimated load was made of, and possibly what types and vectors of loading were present at the time of collapse. There is also the inference that this load, which is shown 2 1/2 hours earlier, purportedly, is the same load that was there at the moment of total failure.

[@TylerLey]

The contractors interviewed confirmed that the load didn't drastically change. Using something that people understand like a car can make it easier for people to understand.

[@josephkane825]

@@TylerLey Ok, Tyler, I understand you were trying to make a mental picture of how large you think this load was. For me, a 12 yard transit mix truck would be a more important concentrated load than a load evenly spread over 100 feet. The AASHTO axle load "Bridge Formula" explanation would make a better example. Why did some particular load at the precise moment or time frame of collapse cause the collapse? Did the total load spread over that 110 foot rectangle concentrate the strain at that particular node and "break the camels back"? wOR - Was a load spread over that large triangle exacerbated by some unusually heavy load. (like a 12 yard Transit MIx truck not in compliance with the Bridge formula) Most people intuitively consider the lower chord of a truss to be the point where the greatest tension and strain loads are located. How were did loads get transmitted to the top chord and Node 10 (which had been known to be overloaded for more than 4 years ) and suddenly precipitate the collapse.

[@josephkane825]

Tyler Since I wrote this critical reply, I have looked up your credentials. I did not know I was pushing back to an individual with such a high level of competence. (I could not find your California P. E.) I still have an issue with the first video I saw, which involved your critical evaluation of the coated rebar. However, for all my other comments which may have been critical I wish to say, that I am not your intellectual equal, and only speak from an inspectors experience. I apologize to you and say I did not mean to offend you. Except where I disagree with your opinion about coated rebar, I did not mean to imply that you were totally wrong in any of my other comments.

[@jacqueslefave4296]

An alternative to a thicker gusset plate would be a suitable alloy steel, I would have recommended a 2000 series nickel steel, about 3.8% nickel would give you about double the strength. Some other alloys would probably work well, too. The stacking of tons of steel on the bridge was inexcusable, I hope that the responsible people spent some time in jail.😬

[@captaincope4303]

I'd be the guy making the case of over loading the bridge and I'd be the guy ignored and scoffed at. Immediately upon seeing that gusset before a word was said I thought, Wow that looks way too thin.

[@Bitterrootbackroads]

Decided to scroll down a bit before writing the same thing, you beat me to it. I bet some of the guys who built it had the same thought. I'm not a professional engineer but have done some design & fabricating that does not fall apart. I've also cobbled a few things together in a pinch with inadequate, but available, materials when things were not critical and seen them fail. The number & size of the rivets (or bolts?) in that gusset tell me it's being asked to do a job beyond what that plate can take.

[@biblestuff1107]

So it wasn't rated as unsafe but obviously was unsafe, or it wouldn't have collapsed. Therefore there was negligence. The people hurt and families of victims should be compensated. And the bridge inspection and grading system needs to be updated.

[@quietcorner293]

I was born and raised in the Twin Cites and I heard about it from another American on a cable car in Austria.

[@marktomlin5484]

Well done

[@jamesmonahan1819]

Harassment of people that know what's going on by the common worker, and removing these people from the decision making process for making waves, by elected officials, leads to disaster. Afterwords, they will blame the person they fired and harrassed.

[@ndenise3460]

I was working sewer/roadwork. I brought up my concerns to the project engineer wrt the pipes being to close to the surface(permafrost heaving) his response was " the book says". I told him I would be doing the same job next year, he probably wouldn't (just about got fired) next year I did it again, buried pipes another 2.5' lower. Gotta love the lowest bidder.

[@Markdmarque]

Very interesting. If a fraction of the money spent on Foreign regime change and space was spent on USA infrastructure they wouldn't have these problems.....PRIORITIES !!..Been to Sicily recently and it seems that after the collapse of the Genoa bridge they are digging out huge chunks of reinforcement on viaduct type concrete bridges with contraflows in place.FLAP FLAP FLAP after a disaster but then after a while complacency sets in and this urgency to inspect and repair bridges gets less important. Sicily has an incredible civil engineering infrastructure with tunnels and bridges spanning mountains and valleys throughout the country but maybe the maintenance has been a bit lax!..Glad that they are checking them out now as these bridges are thousands of metres in the air at points!!

[@ayrendraganas8686]

I looked up how the sufficiency rating you mentioned is calculated (www.fhwa.dot.gov/bridge/mtguide.pdf Appendix B; I hope its the right one) And only 55 of the 100 points consider the structural status and safety of the bridge, the rest being calculated by the features of the bridge (like how functional it is; is it adequate or needs an upgrade) and the how essential it is to the public making up 30 and 15 points respectively. if you look at it like that 50 seems pretty low...

[@SimonTekConley]

"Understanding public" righttt. When the public complains about a tornado warning affecting their TV watching on Twitter, God forbid they have a 15 minute warning now a days, you know that the public is spoiled.

[@TylerLey]

I agree that the public is spoiled but they need to learn that there are trade offs.

[@dvferyance]

They inspected a few months before and it did not get a good report yet they would not close it.

[@mrbuck5059]

Built the year that Mothman brought bridge down in West Virginia.

[@MitzvosGolem1]

paper thin splice plates not spotted by engineers fabricator s Erectors or maintenance. Insane blatant oversight. Super imposed construction live load insane. There is a man and his wife survived in a pickup truck that jumped across failed section unharmed.

[@markfryer9880]

Dukes of Hazard style driving can sometimes save the day. Or maybe it was the Blues Brothers

[@alexanderboulton2123]

The 35E may have similar problems

[@truckerallikatuk]

That's only about 300 tons... that shouldn't be an overload. Even at the lightweights the US runs trucks at, this is less than 10 loaded semi trucks.

[@ajb7990]

The bridge was unsafe.. That's why they lost every law suit. I've looked papers myself.

[@manuelstupu4295]

It's never one thing. All the time there is a multitude of factors. Check all dezasters and you will see something like :"because that wose not good and that guy did not known and so on".

[@CDN1975]

It was 40 years old.

[@krackatowski4081]

My dad drove over that bridge 1 hour before it fell

[@salvadorhirth1641]

I don't understand why mayors don't have all the preventive mentality, this should not happen. Nowadays, lots of people have remote controlled drones with cameras, how about a campaign to invite the public to help and inspect these types of structures?

[@binladen2739]

what the hell was that 580000 lbs??

[@sct4501]

material, rock, concrete

[@sbeallvln]

Umm... 40 years, not 50. 1967-2007=40 years.

[@ugoof855]

The bus there were full of kids and I go to a stable that had those kids there after

[@nerysghemor5781]

Maybe put up a billboard when a bridge repair like this gets underway with the picture of the collapsed bridge with the words, “THIS IS WHAT WE DON’T WANT. BE PATIENT WITH OUR REPAIRS.” Then again people might not appreciate something that blunt given how easily offended people are...

[@markbogen8970]

👍

[@TylerLey]

Thanks Mark!

[@shanemaritch]

Maybe it's just me but as the video goes on he looks like he is medicated or something. Lol

[@sageg58]

Me when playing polybridge

[@carriekegley3652]

i subscribe

[@TylerLey]

Thanks!

[@martyisabeliever]

I dare you to honestly and with full integrity tackle WTC 1-2 and 7 collapses, I double dog dare you!

[@martyisabeliever]

@Vladimir_Bone Spur_tRump I know i know...But Physics is Physics and I saw what i see.

[@martyisabeliever]

@Vladimir_Bone Spur_tRump BBC, Larry Silverstein and Building 7. Bldg's 1&2 97% free fall speed. No "Pile". "The Spire" I wear glasses.

[@martyisabeliever]

@Some Guy "be this way" prelude to an ad hominiem?

[@gravyboat2370]

The world trade centre collapses are fully explained already. I will give you some simple facts . 1. They are a tubular steel construction, their main strength is in the outer walls of the building. 2The world trade centre 1 and 2 are 95% air. 3 the first building to collapse is the 2nd one that got hit .......because it took more damage and was hit lower down . It's not rocket science.

[@martyisabeliever]

@@gravyboat2370 Building 7 gravy for brains. Building 7.

[@jamielake-boyd3600]

We need some engineers with a machine head get these bridges fixed in america.

[@qco5349]

Mike.

[@WeekendsOutsideFL]

Maybe I tend to be politically conservative but we really need that infrastructure funding.

[@qco5349]

Holly Shapiro

[@tedsmith6137]

1) It is obvious the collapse started out of frame to the right of screen, before anything happened at the area you indicate. 2) You don't suppose the 'debris' on the bridge is, in fact, cars?! I think you have failed to tell us anything useful.

[@TylerLey]

Thanks Ted for the comment. Why do you think the failure started somewhere else? Many experts looked at the failure and arrived at this conclusion. The debris was seen by an airplane before the collapse and that was the same area seen in the video. If you are thinking about this subject enough to discuss it in the comments then I think I have done some thing useful.