What Really Happened at the Hernando de Soto Bridge?

Published on Jun 15, 2021
In May of 2021, inspectors on the I-40 Mississippi River Bridge near Memphis, Tennessee discovered a major crack in a structural member. They immediately contacted emergency managers to shut down this key crossing to vehicle traffic above and maritime traffic below. This video provides a summary of the event, including a discussion on arch bridges, fatigue in steel members, and national bridge inspection standards.

Errata:
(1) 8:38 "at minimum, an arm's length away" should be "at maximum, an arm's length away"
(2) 1:14 New Madrid is usually pronounced MA-drid, not ma-DRID.
(3) 4:55 ”It’s hard to understate the severity” should be “overstate”

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Comments

  • 🚧New studio - who dis? Sorry about the audio quality and stark white wall. It’s a concrete box that is also a work in progress. 👷 My coverage of other engineering events: usdos.info/fix/PLTZM4MrZKfW_kLNg2HZxzCBEF-2AuR_vP.html

    • I like the basic background. I’m here for knowledge, not to view marble and chrome.

    • You have nothing to apologize for PE! This is one of the most clear, concise videos I've seen on USdos! All the ridiculous criticism that's going on in comments?... Well, it's the internet! There are no qualifications for admission.

    • Rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrf

    • So fantastic for someone to do an engineering vid and simply lay out the facts as they are known and not delve into conjecture which I see way too much. I did aerospace but have worked in control systems, automation and robotics for 30+ years and the amount of really poor engineering information that is published is staggering. Couple of finer points on this one. The fractured member is not exactly like a string. Its more like a main thread in a string. Its critical nature is that it now offers zero strength which means all the other components now have higher loads to handle. When you lose a main member in ANY complex structure its more like the first domino in a cascade rather than the it breaks and its instant catastrophe. If you go and watch episodes of Aircraft Investigation (I have a pilots license) it often shows that in complex failures there is an "initiating event." Usually there are failures leading up to the catastrophe but then there is "the straw that broke the camels back." As an aerospace engineer with a background in control systems things like Boeing Max-8 where a disaster in progress long before those 2 aircraft crashed. There were vulnerabilities in that system and all it took was 1 of those key failures and "bang." This fracture is a lot like that. Its such a dramatic failure that it will eventually cause the bridge to collapse, much like the Genoa Bridge eventually collapsed after poor maintenance. -> en.wikipedia.org/wiki/Genoa_bridge_collapse *This is just a case where they found it before the collapse.* Another point and I only know this because when I was in post grad one of the professors I dealt with was a fracture mechanic specialist. This came from a friend of mine who had me ask about repeated failures that the companies he was working for was experiencing. A particular machine they had kept breaking it mounts from vibration. It turned out to be bad welding (see below) Couple of points. 1: Metals (and most substances) never fail from ductile deformation, they fail from brittle deformation. The professors favorite example was Blu-Tack. If you stretch it it just stretches' and stretches' and thins and then if you pull fast enough it snaps. When it snaps its a brittle failure. WHAT HAPPENS is that almost all things start with spring deformation (as in it will return once the load is removed) then become ductile and eventually fail. Its obvious once its pointed out and easily seen in metals (even ductile ones). *The ductile deformation eventually work hardens the material which then starts fracturing.* 2: Once you start fracturing most substance lose 99% of there actual strength - as in the ability to kept handling a load. 3: When you weld and the welding involves depositing material like MIG & Arc Welding the bead that is deposited leaves a perfect crack at the end of the weld. Its actually the only way to reliably manufacture a perfect crack that can be lab tested. That's different to all the other UN-intended ways crack form. Its why all welders are taught to grind away the end of welds. Thus was what was breaking the mounts on the machine my friend asked about. They were not grinding away the weld ends. On top[ of all that fatigue is one of the least understood subjects. Its actually incredibly hard to do lab work on because how do you test for what might happen over decades???? When I was doing my degree there was the Japan Airlines 123 Boeing 747 crash in Japan that was from poor maintenance & fatigue on that poor maintenance. en.wikipedia.org/wiki/Japan_Airlines_Flight_123 My structures professor at that time gave us a lecture on procedures, maintenance and fatigue that still hurts my ears. Exactly what his issue was we never found out but he was hyper upset about HOW that came about and what was ignored.

    • @Darth Pseudonym the people who founded new Madrid can't possibly have pronounced it like that besides when you take an already well established names you can't just change pronunciation of it just because you wanna be special.

  • It tells me never trust the government.

  • So sad to think people knew in 2016 that bridge was like that. 4:52 made me mad because I live in Memphis and have been over that bridge numerous times while obviously being cracked 😩the bridge is partially opening tonight 7/30/21

  • Funny, me and my family just came through that area and was wondering why rt 40 was closed completely at the river. Thanks now we know!

  • So basically Arkansas......that's all I need to know.

  • Apparently the caravan bridge in turkey is closed...tf happened?

  • Beyond the mechanical problem there’s the greater “NIMBY” problem: Not In My Back Yard, not on my watch, I’m not going to shut down millions of dollars of commerce, this will ruin my career, I’ll leave it for the next guy, etc., etc., etc…. One of the greatest, most important parts of any project is the human factor: integrity.

  • As Memphian it’s a nightmare.

  • "Crack". That's a serious break through most of the beam.

  • The problem is Hernando built it😬

  • As far as that inspector getting fired, there’s an old saying…. “ fix the problem not the blame!!”

  • bought the steel from china, eh?? haha

  • I mean, if it was under enough stress to break it, it must be a pretty important part of the bridge holding it together.

  • Another excellent video!

  • It's not hard to "understate the severity of the situation" rather it's hard to OVERSTATE it.

  • You'll see, also, at 5:11 at top-center, a pin and hanger assembly, similar to one that failed on CT's Mianus River bridge, bringing down one lane of a span. Bad flashbacks.

  • Don't think you need to be any kind of expert to realize that that bridge needed to be shut down.

  • has mothman been sighted down there?

  • I'm not an engineer-type fellow but I enjoyed the video and learned a lot. I live in Coastal Virginia and we have many bridges to cross. I have seen snooper-trucks (thanks for teaching me that term) regularly on the bridge that I cross almost every day.

  • Once again. Our government FAILED THE PUBLIC.

  • Indicative of EVERYTHING wrong and going on in the world. Check the box. It's fine. This is a rampant problem and higher ups need exposed and held accountable.

  • If its like that there what is it like id say the same all over its completely rotten needs to be replaced

  • For NDA reasons, I will merely ask some questions What if the inspection team had repeatedly brought this to the attention of their supervisors but no further action was taken? Do we actually know what was said and what decisions were made? What resources were made available to the inspection team and were they sufficient to the task? Was proper training and instruction provided for the job? Were rough drafts of the reports censored by those in charge of money? How about we don't just throw the inspectors under the bus (bridge?) without knowing all the facts. Always remember; Health and Safety Departments should be more accurately called Litigation Mitigation Departments.

  • 2:26 "how did engineers know to act so quickly? maybe because half of the bridge was completely severed? any moron wouldve done the same

  • Crazy year lot of bad people lot of bad things happened.... Probably just a coincidence 😉

  • As a bridge design engineer, I quite enjoyed this video. Thanks for sharing

  • We already heard what happened there. They bragged about it. Before it collapsed, that is. After, they started denying it.

  • Government workers don't know the difference between a crack and a break. duh

  • This is the most informative video on any subject that I have ever see . Thank you so much for explaining so much and making it understandable. Hats off to you👌🥰😌

  • I often face challenges in transferring my knowledge to your videos as the language barrier in Engineering is too much to handle even with my rather decent English skills. So my question: The cause of this failure is called stress corrosion cracking like seen (or rather having to be taken into account during calculations) in prestressed steel? The one where we limit it to elastic calculations and limit the tension?

  • Arkansas is a classic “good ol’ boy” state. It doesn’t matter whether it’s Bill Clinton or Asa Hutchinson in charge - you can just look at the State Police diverting public funds into their own retirement system to see how crooked our state government has become. Compounding this problem is the judiciary and U S attorneys office. The system stinks, period.

  • Yeah. I'm from Memphis and this could have been a severe tragic disaster. I wonder if the crack has been there for years and how did no one notice when they were building the bridge from day one?

  • Some fishermen took a picture of the crack and sent that to officials to alert them, 3 months before they close it down?

  • Man! I've gone across that bridge so many times in the last few years....

  • Who is inspecting these structures and how often are they doing this? If it’s contracted out than it’s obviously going to the lowest bidder or someone who knows a guy who is connected to the department awarding the bid to inspect the structures…

  • Just got your video on my feed. Love how you demonstrate the bridge with the model

  • On what planet is a “crack” with a one inch offset, not called a “break”? Answer: Planet Earth. wtf.

  • I am glad that dispite this having been a clear 'inspection failure' I am glad that you keep pointing to the 'natural inevitibility' of failures in just about anything and that the best we can hope for being inspectiin catching faikures before the becone catastrophic Good presentation

  • Exactly why we should be advocating for an infrastructure bill to bring it up to date.

  • Still cringe to think I’ve been over that bridge many times at or close to 80k pounds since that crack had been there.

  • I would not wait for engineers to come up with an idea. I would not cross that bridge.

  • The problem is the idiots in charge piss all the tax dollars away that could be used to build new bridges but instead they put bandaid on top of bandaid to infrastructure that was only designed with a 50 year lifespan. Replace the bridges instead of patching them up.

  • So, you should look into the huge emc billboard that fell at the hard rock arena

  • GOOD NEWS GUY!!!!! Both Parties want to Privatise American Infrastructure out to Corporations and let them take responsibility for Maintenance while ensuring no individual person can be held legally responsible for any negligence.

  • US Gov and FedRes generated more than enough money to maintain and repair all of USAs aging critical infrastructure...but chose to give the money to Privately owned Banks and Investment Funds instead.

  • Shux..... Practical Engineering is becoming an Autopsy Channel for collapsing US Infrastructure.

  • Well presented as always! Nicely done.

  • I can already tell you why this happened. It's because of the mentality of work effort here. No where else can you go to any restaurant, business, or government agency and be told they are closed two or three hours earlier than posted, when they are indeed still on the clock. As a memphian I can tell you that we don't work hard here for the most part. We do the bare minimum and that's it. In other words don't expect nothing when yall come here 🤣🤣 cuz it will shock you.

  • Gross mis-management, highlighted by a token firing of a mid-level inspector. Nice job guys. Our nation is slowly decaying under our feet and fat, lazy old men are responsible. Supervisors deferring to subordinates who, in turn, defer to subordinates, etc., etc. smh America's infrastructure is in dire peril, across the country.

  • This is the most boring shit i’ve seen all week

  • What do I think? lol The shadow of the ax hangs over it all. I cannot stop thinking the futility of it all is proof of my blunder.

  • I hope you and your team are making a ton of dough off these!

  • 4:33 I pass this bridge every day and always wondered how the arch sat in the middle. For those wondering this is the Fort Pitt bring in Pittsburgh Pennsylvania

  • whats the song in the intro here?

  • The fact that that fracture might have been on the bridge since 2016 just reminds me of the poor state of the Golden Gate Bridge. Though it's hard to tell from the outside, that damned bridge has so much damage the management just ignores

  • Build in 1973 means build without computer. In that time it was oldfashed calculating and then divided times two, That is the reason that the bridge is not collapsed

  • It's New Maadrid, long "a", not Madrid like the city. We like to pronounce things differently in the Midwest, like Karo, spelled Cairo, or New Berlin, accent on the first syllable, not Berlin like the city in Germany or the composer.

  • Another case of shit rolling down hill!

  • 5700 comments... ill get yelled at for this, but here goes: span is too long for a tie arch that is not fully 2 arches. the stylishness where the upper arches meet increases load to the outter ends of the arch. only way this design arch could be reliable long term would have been to build with abutments or have added a means to transfer force to a larger center pier

  • That's absolutely right. 1 Person Should NOT be responsible for such a vital structure as this.

  • Terrific job on this video. What on earth happens to all of the barge traffic? (July 26, 2021, St. Joseph, MO.)

  • I have dealt with ARDOT.. That is one slow ass agency. They take forever to approve the slightest thing! Then something like this and they still don’t get it done. It is clear to me why Arkansas produced a President as bad as Bill Clinton! Just imagine all the ladies that have to sell themselves to get the inspection of the bridge done properly! I bet Bill wishes he still had a hockup now that his buddy Jeffrey Epstein is long gone! They were thick as two porn stars when times were good! Thank God the country was spared the Hillary Presidency!

  • HOLD UP!! did you just casually glide past the fact they knew the crack was there 2 years earlier??? Because that's kinda A BIG DEAL!

  • In california, it was discovered a few years ago that for many years, Bridge Inspectors were just filling out paperwork and never actually inspecting the bridges.

  • Great video!! I live the at home example to show how the load is distributed!

  • Thank you for explaining it in a way I can understand it. I’ve driven across that bridge many times. This is kinda scary.

  • The democraps are so worried about a vote they flood our country with illegals Which makes our roads,schools,jail ,law enforcement,housing ,medical,sewage systems and food supplies etc Get overwhelmed if they don’t care about those issues you know maintenance and preservation of our original infrastructure is the least of there worries

  • Sounds more like some government officials decided to put off the repair due to overall price from fix and from shutting it down but this is just my opinion from dealing with officials in the past

  • 4:51 This model only represents the bridge if it was made in a different way. The i40 bridge with the crack has two sides, one with the crack and the other side with no crack. Hypothesis: If you were to add another rope to the model that you demonstrated, the model would not collapse. I understand that this is just a demonstration and is not an actual representation of the bridge, but you can see the bridge were the beam on 1 side of the bridge has fractured but the other side of the bridge seemly has no fractures.

  • I crossed that bridge, with the crack there. I'm glad that not only myself and my dog crossed that bridge safely, but others did too before it was closed. What could have been and the lives lost...

  • Roflmao at the New Madrid thing.... People here in the midwest-southern region, love to butcher intl names. Versailles, MO is pronounced Ver-SALES Nevada, MO is Ne-Vay-duh And they wonder why they get treated like illiterate stupid folk.

  • Interesting that the bridge shown as an example of the tied arch design was the Fort Pitt Bridge in Pittsburgh, PA. I've been over THAT bridge way more times than I care to remember. This incident reminds me of a similar one back in the late 70s, involving the I-79 bridge over the Ohio River at Coraopolis, PA. A crack was spotted by a towboat crew passing under the back channel section. That crack was later determined to be caused by a then- new welding process whose name escapes me, but has since been banned in bridge construction. The process introduced a brittleness to the surrounding steel that was aggravated by the bitter cold weather the area was suffering over the course of several winters at the time.

  • I'm an inspector and you don't want to know how bad American bridges are and how rarely we are allowed to inpect them.

    • I the video he states every couple of years but that's a lie. They won't let us because it's not in the budget and when we find something they sit on doing anything for as long as possible. Firing that inspector was to save face.

  • De Soto’s down but Cosmo’s got the caboose

  • Have you covered the old Sunshine-Skyway Bridge Incident in early 80's St. Pete FL??

  • Why haven't they built a Temp. Span in the interim??

  • How would they go about fixing such damage?

  • Is it possible to weld that huge crack or would they have to rebuild the bridge ?

    • Ok thank you for the info cause the size of the crack in the bridge was super thick I'd hate to think that I would be driving on that bridge ps how old is that bridge I know it must have come from a steel mill somewhere

    • Since that piece has already failed, they will likely cut it out to a determined safe margin, and splice in a new member. The splicing will likely be done with fish plates and bolts to make the joints. Welding would possibly weaken the steel surrounding the new weld by burning the carbon out of the surrounding steel.

  • Yep. I am glad they closed it. I was pissed off with the 45 minute detour and delay driving back to Arizona, but now I understand totally.

  • Wild to think I had driven accross this bridge just 2 months prior on my trip to Memphis.

  • This is the best video yet. If you made a video about the golden gate bridge collapsed. I am happy the Hernando Desota bridge didn't collapse.

  • how close did this bridge come to failing??? umm that big ass cracked beam looks like a fail to me

  • I bet that inspector was thinking to himself "f@$!, why me? Why couldn't Ralph or Bob have found this! God damn, now I have close this stupid bridge. This was supposed to be my day off!"

  • Should've called Andrew Camarata

  • What really happened was corruption. Paying uniformed mercenaries to harass and eat out the substance of the citizenry to fund a privately owned prison industry. What happened is corrupt politicians pandering to socialist special interests, instead of to funding maintenance and repair. Inspections every 5 yrs instead of every year, because funding... that crack should have been discovered and fixed, long before it became a break. This was an infrastructural attack by treasonous politicians claiming negligence as an excuse for liability.

  • Cracked beam....bridge broken.🤷‍♂️

  • I'm just here for the Al Gore rhythms. BTW, I enjoy your videos. Thanks!

  • Being the failed section the I 40 bridge has been removed, hopefully there is a failure analysis .to be under taken to determined the how and what caused the fracture. Ret. Me Eng

  • Rap music done this

  • They say itll take til August 2021 to fix it. Never knew about this til today. only read that someone got fired.

  • So just a comment here... While the earlier inspections missed this defect, a later inspection DID catch it BEFORE catastrophic failure, even if was pure luck that kept the bridge intact. So even though the inspection process was flawed, the process of inspections actually fulfilled their intended function and identified a problem before it resulted in a failure of the structure. It's inexcusable for it to have gone unremarked for so long and probably a fair number of people need to answer for that but, nevertheless, the inspectors that caught it still kept the public safe and they deserve our thanks.

  • Ahhh education. Thanks for taking the time to share this , sir.

  • I’ve always wanted to know what bridge this was, I remember falling asleep when I was on a car ride home as a kid and woke up for a couple minutes and have a vivid memory of seeing this huge ugly ass bridge and assuming it was near my house for so long but never saw it. This explains it… this thing is over a hundred miles away I just didn’t have any concept of time since I fell asleep 😂

  • thanks but what is happenning to the inspection protocol

  • As a lifelong Memphian it is weird to hear you talking about and even just seeing videos of Memphis.

  • Don't worry guys we fired a single person this clearing us of all wrong!

  • I don't know if I would consider this bridge iconic. It's quite ugly honestly.

  • update: just a few more weeks, folks. apparently there were a few more issues needing attention, and then we'll see. let's see if the elephant walks all the way across.