6 Construction Failures, and What We Learned From Them


Scientists sometimes get a little excited when an
experiment doesn’t work the way they expect it to. It’s an opportunity to learn something new about the
world, and they can always change the expriment a bit to try again next time. Engineering… is a little bit different. Desginers and engineers generally prefer to find out
something’s wrong before it’s built instead of after, because engineering failures can be disasterous. But engineering failures have
happened and, if nothing else, they’re an opportunity to learn
what not to do next time. When it opened in 1878, Scotland’s 3.2 km
Tay bridge was the longest bridge in the world. It was so impressive that queen Victoria knighted
Thomas Bouch, the Tay bridge designer after she took the train across it. But on December 28, 1879, a train was
crossing the Tay bridge during a violent storm, when the middle of the bridge collapsed. The bridge, the train and the 60 or so people
on board crashed into the water below— there were no survivors. An official investigation found so many problems
with the bridge’s construction and design, that they couldn’t even figure out what failed first. But according to their report,
Bouch did just about everything wrong. They tested a lot of the bridge’s
surviving components, for example, and found that they couldn’t stand anywhere
near the pressure they were supposed to. So the bridge would have failed eventually, anyway,
and the storm just accelerated things. And when investigators looked at the columns
that had been holding the bridge up, they saw that they were broken at the bottom,
so the columns might have been responsible for the bridge’s collapse. The winds could have made the train rock as it went
along, maybe even forcing it against the bridge’s walls. If that had happened, it would have put
a lot of extra stress on those columns, breaking them and bringing the bridge down. Whatever the reason the Tay bridge fell,
engineers found even more problems when they looked at some of Bouches’ other projects. Some of their components were either just
as badly-made as the ones on the Tay bridge or they were arranged in ways that meant
they couldn’t hold much weight. Apparently, he just wasn’t a very good engineer. The Tay bridge disaster made it clear that
those projects were also ticking time bombs and that bridge inspections had to be way more
thorough to stop these kinds of things from happening. The other bridges were either quickly repaired…
or destroyed to prevent another disaster. But The Tay bridge, of course, was not
the last bridge to collapse. The Quebec bridge was set to be
the longest cantilever bridge in the world when construction began in 1900, but it collapsed
TWICE before it eventually claimed the title in 1917. Cantilever bridges are made of big bulky parts that
support relatively flat sections between them. And during construction, workers kept
noticing that some of the support pieces were bent more than they should have been. They were holding way more
weight than they were designed to, partly because the bridge ended up longer
than it was originally planned to be. But to save time and money, extra support wasn’t added. The designers hoped that the problem
could be fixed as construction went on, but at the end of the workday on August 29, 1907,
parts of the bridge collapsed under their own weight, killing 75 workers. Construction resumed after investigators
figured out what happened. Their main conclusion was that the bridge’s
components just weren’t strong enough. So the bridge was rebuilt. This time
much bigger and stronger. But, all that extra metal made it much heavier, too. was hoisted into place in 1916 the equipment bringing it up broke and they plunged into the river below this time 13 people died the Quebec bridges after was a reminder that it’s important to make sure that the thing you’re building can carry the weight you’re putting on it and it probably would not have happened today over the last century engineers have developed tons of new mathematical techniques and computer programs that probably would have caught the first collapse long before the bridge was built even before it opened in nineteen forty people noticed something strange about Washington State’s tacoma narrows bridge it moved gentle winds could make the long suspension bridge flex up and down by meters at a time making it hard to drive or even walk across the British designers tried to keep it from bouncing so much by installing shock absorbers but they weren’t very effective and then about four months after it opened to the public one of its cables snapped from how high the bridge was bouncing a strong wind and the other cables started to slide around this let the bridge start twisting back and forth instead of bouncing and eventually the middle broke off and fell into the water below unlike the Tay and Quebec Bridge disasters there was only one fatality this time a dog named Tubby Tacoma Narrows failed because of something called aeroelastic flutter when that first cable snapped its side of the bridge fell slightly because it was less supported then other cables on that side pulled up like stretched out rubber bands and the bridge started twisting back and forth then the wind gave each twist a little boost so small boosts built up over the course of the morning and eventually twisted the bridge apart engineers learned their lesson pretty quickly and reinforce the bronx Whitestone bridge in New York which is also known to flex in the wind and that bridge is still standing today but not all failed construction projects has been bridges tho the 40-story hyatt regency hotel opened in Kansas City, Missouri in 1980 and it quickly became known for its innovative atrium which featured three long walkways that seemed to float in the air the hotel called them “skywalks” instead of being supported by pillars each skywalk was suspended from long rods hanging down from the ceiling the second floor skywalk hung below the fourth floor skywalk with the third floor skywalk off to the side on separate supports their unique design made the huge atrium an ideal place to host events and parties like the one that the hotel hosted on july seventeenth 1981 about 1,600 people attended hundreds danced and talked in the atrium while others milled around the hotel and check out the famous skywalks then at 7:05 p.m. two of the skywalks suddenly collapsed without warning a hundred and fourteen people were killed and more than 200 were injured making the incident the deadliest structural collapse in US history until 9/11 happened 20 years later investigators found a small last-minute change to the rods holding the to collapsed skywalks that meant that instead of each holding its own weight they were linked together originally rods went from the feeling all the way through the fourth floor skywalk and down to the second floor one with pieces underneath each skywalk supporting its immense weight but after the change the second floor skywalk hung from the fourth floor one so supports for the fourth floor skywalk weren’t just holding up 129 metric ton skywalk they were holding up two of them it also didn’t help that to save some money the building materials themselves weren’t quite as strong as they should have been and on the night of the party the extra weight of a couple dozen people standing on the skywalks proved to be too much what seemed like a tiny change to their construction turned out to have terrible consequences Manhattan Citicorp Tower which is now just called 601 Lexington Avenue proves that projects with problems don’t always end in disaster the skyscraper’s triangular top makes it stand out from afar but you’d notice something else if you were just walking by Citicorp Tower was built on stilts which turned out to be a problem the stilts were built to accommodate a church next door that essentially said they could build a skyscraper on the property as long as it didn’t block the church so the building’s designers just decided to start most of the tower nine stories up they knew that such a tall building with so little on its bottom floors could be prone to toppling over on strong winds so they wanted to make sure that it could withstand even the strongest winds blowing against its windows so they added extra weight to the top of the tower that moved in the opposite direction of any lean the wind might cause wind against the skyscraper’s corners usually just sort of slides past the building so Citicorp Tower’s designers didn’t even bother checking for them and that probably would have been fine if the stilts were on the corners but because that weird thing with the church the building’s stilts are in the middle of its sides and in 1978 about a year after the center opened a college engineering student figured out just how unstable the building was calculations showed that storms strong enough to topple the tower hit Manhattan about every 16 years pretty alarming the building’s designers didn’t tell anyone other than the New York City Police Department and the Red Cross who helped them secretly work out an evacuation plan while the building’s internal structure was quietly but frantically improved every night after the office workers who were using the building went home braces that had been bolted together during construction were now welded steel plates making the connections between them stronger so Citicorp Center would be sturdier in the wind in the end everything turned out fine the repairs were finished after just three months and the only major northern hurricane of the year missed New York City but almost no one knew about any of this until 1995 when someone finally spilled the beans on just how close New York came to having a skyscraper fall over in a powerful storm London’s Millenium Bridge was another project with a major design flaw that got fixed before it led to disaster the bridge opened on June 10th 2000 as a way for pedestrians to cross the River Thames it was touted as an engineering accomplishment at the time a sleek new bridge to mark London’s entry into the 21st century then it promptly closed for repairs on June 12th 2000 and no I did not say that wrong it was open for a grand total of three days the problem wasn’t weight or wind or waves the bridge was plenty strong enough to deal with everything it was supposed to hold instead it was the people themselves who were unintentionally making the bridge sway back and forth like a pendulum some sort of random coincidence would get a wobble started like a bunch of people randomly stepping on the bridge on the same side at the same time and with up to 2,000 people crossing at once that sort of coincidence was bound to happen sometimes then once the wobble got started it was easier for people to walk with that wobble than to fight against it so many people walking in sync made the wobble get even bigger and soon it got so extreme that people couldn’t walk across the bridge without grabbing the side railings the bridge probably wasn’t in danger of failing because people would stop walking once the wobbles got too big and wait for them to die down before continuing but the wobble would have still weakened the bridge over time and the bridge’s engineers knew what happened to Tacoma Narrows they weren’t taking any chances so they decided to close the bridge pretty much immediately before the wobbles started causing other problems they spent the next two years adding dampers all along the bridge which absorb most of the force from pedestrian steps to keep the bridge from swaying the bridge re-opened in 2002 with all the dampers firmly in place and it’s been a famous tourist attraction ever since designers and engineers are human and occasionally they make a mistake that isn’t caught or there’s a factor that no one anticipated sometimes like with the Citicorp Tower and the Millennium Bridge the issues are fixed in time in other cases they can lead to catastrophe but generations of engineers have studied and learned from these failures and there’s no telling how many potential disasters have been avoided because of those lessons thanks for watching this episode of SciShow which was brought to you by our patrons on Patreon if you wanna help support this show you can go to patreon.com/scishow and don’t forget to go to youtube.com/scishow and subscribe is a suspension bridge that connects two mountain peaks and between them is an absolutely stupefying drop of almost 500 meters even though the bridge is pretty remote it does

100 thoughts on “6 Construction Failures, and What We Learned From Them”

  1. Yah, I remember the sky walks falling. A couple of dozen people on the skywalks? I recall more. It was a party atmosphere. People dancing, tapping their feet to the music. So many bodies keeping time. Never march an army across a bridge.

  2. Regarding the last example of the foot bridge which would start swinging/swaying with the movement of pedestrians all moving at the same time building up a harmonic distortion, even the ancient Romans observed this. They quickly learned when crossing a bridge to have the foot soldiers all march out of step, ie. not everyone dropping their feet at the same time. I guess some simple problems and their solutions have been lost to history over the ages.

  3. I heard that in Roman times, the chief engineer was required to stand under or on top of any arch they designed, as the supporting wooden frame it was built on was removed.

  4. I was studying Civil Engineering in 1981. The Hyatt skybridge disaster was driven home big time in classes.

  5. You forgot Connecticut: Hartford Civic Center Roof Collapsed Jan. 1978 and Mianus River Bridge collapsed over I95 in 1983.

  6. Sorry buddy, but none of the 3 buildings at the WTC were "structural failures". Controlled demolition is not a structural failure

  7. HORRIBLE. This guy talks too damn much and doesn't say ANYTHING. Don't watch his videos if you want to learn anything.

  8. Another factor, the joints linking the rods supporting the Hyatt Regency skywalks were improperly constructed. Had they been done right, the collapse probably wouldn't have occurred.

  9. Hey! I can be an engineer to! All projects would be disasters but, I would have plenty of company. Wouldn't even stand out.😀

  10. My dad was a combat engineer in WW2. He told me all troops were trained to break their steps while marching over bridges.

  11. What about the West Gate Bridge in Melbourne, Victoria (Australia)?
    https://en.m.wikipedia.org/wiki/West_Gate_Bridge

  12. If you’re making a video about spectacular engineering failures without mentioning modern China even once, you’re just not doing your research: a skyscraper in Shanghai that topples over; dams that burst and kill thousands of people; a city as big as anything in America in which nearly every building (except for Communist Party ones) collapses in a single earthquake; a highway made with bricks torn from the Great Wall with no curbs to stop for hundreds of miles.

    Please do some research and remake this video properly.

  13. I'm surprised they didn't mention that walking bridge that collapsed in Florida around 2017. That was nasty and I can't believe something like that happened in this day and age

  14. The london bridge was wobbling when roughly 27 people walked on it… the vibration set up waves that amplified that and it got worse…
    Its called resonant frequency and everything has it….

  15. I thought the video for the #3 bridge was taken during an earthquake??? If not then there is a nearly identical video of a nearly identical bridge that was taken during an earthquake…

  16. The Hyatt skywalk collapse resulted in the architect being sued. The architect signed off on a construction design that changed the load. The architect was held criminal responsible. Doubt he ever served time, but his firm was ruined.

  17. It would appear that architects hadn't heard of resonance or forced response in the year 2000. Perhaps they shouldn't be allowed to design bridges, and be forced to give the job to real engineers.

  18. How could you not talk about the chernobyl sarcophagus yeah it was a rushed thing and they knew it wouldnt last long at all which led to the mega tomb which was a pretty big achievement but besides that if the megatomb wasnt bult or they waited longer the sarcophagus would have collapsed within it self shooting radioactive dust everywhere you couldnt talk about that but a bridge that had a wobble which made people stop walking made it?

  19. I was working at UPS hub in the 80's when a 42lb tractor part fell off the conveyor 20' above and slid down my back thus crushing the metal wagon I was pulling. I asked if they would put up a safety railing and they said they only ever paid $40,000 in death claims so it was cheaper to let somebody die then to put up a rail all over the country. At the time they had a union too. I quit wondering what else they endangered their employees with.

  20. You forgot to mention building 7 at the world trade center. It collapsed when debris from the twin towers were hit by two airliners.

  21. All of us Structural Engineers have studied the "failures" of all 6 cases shown in this video. As technology advances and new techniques become available for us to use, we always go back and review work done by others. It is a constant learning experience for us in the field. The two incidents that have most of us interested in is Ponte Morandi and Cancura Bridge. Construction wise Florida International University pedestrian bridge collapse is what keeps me up at night, because it could happen again.

  22. Sugestion: Make a video about the Hercilio Luz Bridge, in the city of Florianópolis, Brazil. It connets the continent to the island of Santa Catarina (also know as the magic island).

    the story is a mixture of design failiures (with collapsed her twin bridge), corruption, burocracy and delays caused by the fact it became an historical landmark. Long Story short: the bridge was partially closed to car traffic in 1981 and pedestrian in 1992. Its in a MAJOR reform and its expected to be open for traffic in the new year of 2020

  23. What about that Mall collapse? or was this only in US? There were also 2 damn collapses that resulted in many deaths.
    https://en.wikipedia.org/wiki/Sampoong_Department_Store_collapse

  24. No mention of the tower in South Korea that collapsed because the owner kept cutting the size of the supports?

  25. Boston's John Hancock tower also could have collapsed in the right wind conditions and it too was kept a secret while work was done to shore it up. Not to mention the fact that the windows kept popping out when it first opened! We called it the Plywood Palace!

  26. An interesting one is the tall building in Leeds, UK that killed a guy because it created strong winds around itself somehow. It blew up truck over in top of a guy.

  27. Yet another presenter who doesn't talk like a normal person. Enough for me – I don't need to listen to a tirade.

  28. Before modern engineering structures incurred increased costs because an additional 10% of structural integrity was built in for any problems not anticipated. With modern engineering these same structures could be built considerably cheaper and the savings could be applied to help with burying the dead and paying for the legal damages.

  29. Washington has had two major bridge failures, the Tacoma Narrows and the I-90 floating bridge sinking during renovation work.

  30. EPILEPSY – What's wrong with the man in the video–there is literally no quarter-second when he isn't gesticulating wildly, with sways, shakes of the shoulder, and other body part movements. It's distracting–literally annoying.

  31. 2: What it should have taught us is that if the professional workers who deal with that stuff on a daily bases say that it's not gonna happen, than it's not gonna happen. But people who are responsible for it fear more of losing their job/money than 45 human lifes and they get away with it.
    [edit]
    5: same thing even worse, letting thousands of people work in lifethreatening danger just to hide their asses.
    Outro: yes making mistakes is human but standing tall for the deaths you've caused is… well I don't know, dignity?

    nice video!

  32. So just how does a skywalk or a bridge let people know they are going to collapse! Do they think it's going to say Hey I am going to fail you better run! Just like when someone says with out warning lighting strikes.

  33. What about WTC7? The entire building collapsed due to an isolated fire? How does a 'failure' of that magnitude not get a mention? I won't mention the other two massive elephants in the room for fear of upsetting Americans who swallowed the official narrative.

  34. Wonder if Burch was transported for his lethal incompetence. Probably not, although he probably deserved it more than anyone who actually was.

  35. Couldn't find room for Melbourne, Australia and the 1970 nWest Gate Bridge collapse? You're not trying.

    https://en.wikipedia.org/wiki/West_Gate_Bridge#Collapse

  36. In my days as a student we used to say that an engineer is someone that designs a bridge that stands but doesn’t know why. A professor is someone who designs a bridge that fails, but knows exactly why.

  37. Most design problems come from the famous, "It's not my problem." attitude of most workers. At All levels of the work force. Being able to see the Big Picture and having a Strong and Responsible Work Ethic, is rare. If you do have one, No One wants you anywhere near them in case another person of responsibility makes a comparison.

  38. Number 4 wasn't an engineering failure though. I remember learning about it, the construction company decided to save money, instead of installing the long rods they opted for smaller ones which were much cheaper without realising the bolt on the first bridge would have twice the weight. They did this despite the design was to use longer rods.

  39. The segment on the Citicorp Tower is loaded with inaccuracies. Better to read The New Yorker article: https://people.duke.edu/~hpgavin/cee421/citicorp1.htm

  40. "…if you enjoyed this video and would like see more from the definitive channel for construction, subscribe to the B1M"

  41. You skip major details at number 4… have watched a documentairy about that one a day ago and its not just because how they used the rods, it how they conected the rods in the beams that is one of the biggest failures to why it fell down. The beams caved in under the presure since they were turned inwards instead of outwards wutch would have made them stronger, but now the bolts basacly traveled straight trough the beam once the beam failed under the presure.

  42. The problem with the Citicorp tower wasnt because "wind slides past the corners". Its because in typical sky scraper design the 45 degree wind strength is usually way stronger than staight on wind. So they didnt take the time to calculate the strength of 45 degrees. But because of the unique design, it was very weak on the 45 degrees.

  43. I would think proper plan review would be a better preventative measure than bridge inspections to find defective designs

  44. Wasn't the Millennium Bridge destroyed by some bad guys ( They're called Todesser in German but i don't know the English name) in Harry Potter?😁

  45. What dumbass though hanging one massive skybrige off a second one was a good idea without reinforcing the supports! Holy hell someone was smoking something strong that day.

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