How one design flaw almost toppled a skyscraper - Alex Gendler

Dig into the unique engineering of New York City’s Citicorp Center tower, and the design flaw that threatened to topple it.
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In 1978, Diane Hartley was writing her undergraduate architecture thesis when she made a shocking discovery. After weeks of poring over the Citicorp Center’s building plans, she’d stumbled on an oversight that threatened to topple the 59-story tower into one of New York City’s most densely populated districts. Alex Gendler digs into the skyscraper’s potentially deadly mistake.
Lesson by Alex Gendler, directed by Nicholas Paim, Alopra Studio.
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[@asiyasaiyed]

Little did Diane Hartley knew her homework was going to save lives. Astonishing how a student notices things that great engineers missed.

[@applecider3616]

I think I understand why the head designing engineer would disregard a student's findings. Just sometimes, all it needs is a small sprinkle of pride to make a domino effect of unlucky events that leads to a full blown disaster

[@JC-vt4mt]

imagine if the engineer really neglected the concern... phew

[@Narrowcros]

A great engineer can't be great in every single detail, giants need assistance sometimes

[@FrostArchon]

Well, the engineer didn't miss anything in his calculations, as the structural footing he designed was enough to support the weight as he confirmed. She did however, make him recheck the construction of which he noticed that the bolted joints weren't as strong as welded joints because someone changed it without his approval. In the end the corner-wind was a non-issue.

[@jerardosalgado4506]

@@FrostArchon agreed. This video made LeMessurier seems like the villain when he did his due diligence to double check his work as suggested by the student.

[@REEEPROGRAM]

"if you want to be lucky Do your homework" **FURIOUSLY ANSWERS MISSED ASSIGNMENTS**

[@frgal1336]

*quietly googles answers to the missed assignments*

[@tajrice5398]

**suspiciously gets an answer wrong so the teacher doesn't suspect anything**

[@johnather]

@@frgal1336 *just does missed assignments normally*

[@ThatOneOddGuy]

Off to do homework that I postponed *untidyly!*

[@hasanmuhammad6651]

So that's why Yukko is so unlucky

[@izzyshine19]

I am glad Diane Hartley is finally getting the recognition she deserves.

[@georgplaz]

what about the cash she deserved?

[@CharlieQuartz]

@@georgplaz For happening to cause the engineer to check the plans and notice an unrelated issue with the bolts? The corner wind wasn’t an issue after they fixed the structure to match his original plans.

[@jerardosalgado4506]

@@CharlieQuartz I agree this is something I'm lost about too. Her 'discovery' had nothing to do with the safety issue that the structural engineer discovered. It was an unrelated issue all together and is the fault of the contractors who made the building.

[@r.vincenta.9678]

@@CharlieQuartz there is a phenomenon called the wind corner effect where air blown on a square corner accelerates. Buildings in close proximity can cause a reduction of wind pressure thus creating turbulent wind channeling by the venturi effect. This of course has low impact on the structural integrity of the building (assuming it's up to spec) and high impact on passing pedestrians. Hartley was essentially concerned with a possible issue and probably pressed too hard with the concern before being told hakuna matata. I'm skeptical that the head guy took it seriously but he did, at least, take a last look on the plans to check if everything was up to spec.

[@r.vincenta.9678]

@@CharlieQuartz it always pays off to do your homework eh?

[@hardyjoshuanto]

A lot of people seem to misunderstand: the corner wind was never an issue. there was nothing wrong with the strucural design but the bolts used by the contractor. Diane Hartley pointed out a completely fine issue but she made the engineers review the construction and they found a totally different issue (the bolts).

[@escobar3349]

Yes. You are right.. ❤️

[@kyunchee1686]

True. 👍👍👍

[@-SimonRiley]

👍🏻

[@jonathan_herr]

And the weakness of the dampened system! The power going out!

[@ninofromkitchennightmares1497]

It’s also slightly misleading There wasn’t a design flaw at all The Engineers Added the bolts instead of wielding it together

[@MAGACult]

My engineering professor always referred to this specific scenario. All through undergrad, he always always always stressed how important it is to have multiple engineers actually look at plans, not just glance at them and assume the first caught everything.

[@pixynowwithevenmorebelkanb6965]

Lemessurier: so i got a call saying this is unstable Company: oh dont worry we bolted it Lemessurier: ok good thing, WAIT WHAT??

[@pixynowwithevenmorebelkanb6965]

Ted ed had a stroke and i dont know what to comment Help

[@deliocache2528]

@@pixynowwithevenmorebelkanb6965 it isnt ted ed. It is a spam bot. Report the comments it made.

[@TheBeatboxHitmanTwo]

I never get tired of these kinds of videos. Gives me the feely feels. Feels.... Feely *Mr. Krabs voice*

[@futuregmchess1561]

@Ted Ed Bruhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh what's your username LOLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL we all know that isn't the real TED-Ed btw

[@Mariana16562]

I study architecture, and regardless of what you think of Lemessurier, using a computerized counterweight to stop winds to affect a building's stability is one of the most effective and cool solutions to wind forces I've ever heard

[@richardwagon6433]

Have you seen the giant spheres that they hang on the inside of skyscrapers like a pendulum to help counteract the building oscillating from wind?

[@dondee5439]

Yeah, because a counterweight that has to have electricity to work properly is a good idea. Storms never ever cause power outages so it all makes sense. The SARCASM in this comment runs at a high level.

[@freeeggs3811]

@@dondee5439 even without the counter weight the building could still handle strong winds.

[@BiggieCheeto]

@@freeeggs3811 Winds are strongest during storms pretty counter intuitive, no?

[@SvSGaming]

@@BiggieCheeto Well don’t forget that the mistake made was approved without his knowledge. If the building had the proper joints it would have been fine during a hurricane, but somebody opted for cheaper bolts without telling him.

[@mitodrumisra8972]

Probably he was the guy who said: *'Trust me, I'm an engineer!'*

[@guiorgy]

Oh sh*t, I think I'm outta here!

[@jonelbolanos9248]

hahahahaha

[@kingraijun9908]

more likely: "i'm 'the' engineer"

[@DoubleDDD]

" I build many building's, well some of them even fail "

[@alvinip9128]

it is not his design that was flawed it's just that the construction company made changes on their own which could've caused a lot of deaths without even contacting the engineer

[@NihilistEmier]

Watching ted ed is as soothing as mining diamonds .

[@ThatOneOddGuy]

Can I join u in maiming diamonds then I steal a few good rough ones

[@enjybadran7876]

@@ThatOneOddGuy you are known not unknown

[@seventeencarattrash]

@@ThatOneOddGuycan I join bestie? ❤👄❤

[@weirdalexander8193]

We talking Minecraft diamonds or blood diamonds?

[@ThatOneOddGuy]

@@enjybadran7876 then what is my name young one

[@dh4913]

Basically my math exam, "How one flaw in calculation almost toppled a teenager's graduation."

[@Unknown12462]

@Ted Ed shut yp

[@mihaleben6051]

@@Unknown12462 bro managed

[@West-brook]

Its hard to believe that one person doing their homework saved hundreds maybe thousands of lives

[@johneyon5257]

no lives were in danger - the ironic corollary is no lives were saved - see the NIST reassessment using modern technology of the wind loads on the Citicorp building - Hartley and LeMessurier were wrong to be overly concerned about the quartering winds

[@roheemolaiya2018]

"If you want to be lucky, do your homework" Most students: that sign won't stop me cause I can't read B)

[@johnather]

Lol

[@Arunabhh]

kzbin.info/www/bejne/b3q0h5ioqM6ehK8 ❣❣❣❣💯💯

[@-SimonRiley]

Where's the B?

[@Sam-ey1nn]

I worked in the top floor (59) of this building for several years. Like all tall buildings, it does sway somewhat during storms. And it sure is scary being up there during a storm with the building swaying.

[@johneyon5257]

think of what the sway would have been with the damper

[@Nitephall]

That base design freaks me out. Even with the repairs I don't think I would ever go in there, especially now that we know buildings can crumble to the ground for no apparent reason.

[@johneyon5257]

we've always knew buildings could crumble to the ground - but always with a reason - as the recent collapse in florida - but keep that in perspective - there are probably millions of buildings that soar even higher - that are older that the Florida building - and have stood thru storms and earthquakes - and remain standing - the causes of the florida building's collapse is not only known - but warnings about its immanent collapse were visible - but the observers were indecisive people - the weakest link in many tragedies

[@NoahJaeger]

Actually Hartley didn’t think there was anything unaccounted for, but instead thought she was missing something in her calculations. She also never talked to LeMessurier and he is on record saying he wished he knew who she was. It’s likely her name got lost in the flurry of trying to fix the building. The New Yorker could have never known who she was because LeMessurier never knew who she was.

[@pvic6959]

wait how do we know this?

[@rasmusgarbonzo1411]

no

[@EmonEconomist]

@@pvic6959 Yes, this was my question too - how did we (and TED-Ed) find out about Hartley if she wasn't credited? I want to hear the rest of that story.

[@zofar9565]

It was after BBC aired a special city group tower crises, one of the viewers was Diana Hartley.

[@johneyon5257]

it was a phone call from student Lee DeCarolis (now an architect in New Jersey) that prompted LeMessurier to recalc the wind loads - that led to his concern about the bolts - that led to the multi-million dollar reinforcement however - a recent re-analysis of the wind loads on the building using modern technology showing the quartering winds were not the threat Hartley and LeMessurier thought - and the original building may not have collapsed after all - the structural design still needs to be re-analyzed to be sure

[@Youmu_Konpaku_]

She saved thousands of lives by doing her thesis, but here i am procrastinating on mine xD

[@MarkWTK]

what is yours about?

[@Youmu_Konpaku_]

@@MarkWTK just stuff about doing a survey to my classmates about their interaction with their family with the lockdowns going on. Our teacher forced us to do it solo and when i feel overwhelmed i just get too lazy to do anything.

[@lucretius8050]

You are just waiting for the right time.

[@pvic6959]

good luck!

[@entropydagoat]

Everything's really interesting when it's 3am

[@gilvinzalsos8734]

The engineer wasn't at fault here, it's the project manager or whoever tf made the decision to cut the budget and use cheap materials for those security bolts, but if it weren't for hartley the head engineer wouldn't have rechecked. credit's still on her >:)

[@johneyon5257]

credit Lee DeCarolis - the student who prompted LeMessurier to recalculate - and initiate the reinforcement - - to her credit - Diane Hartley did anticipate LeMessurier with her concern about the quartering winds - but both were probably wrong - as determined by recent re-analysis of the wind loads - the building may have been fine - i suppose the bank can consider the loss of a few million in reinforcement as an extra cushion of safety

[@alphabladelm2011]

Props to Hartley for warning Lemessurier about the design flaw and Lemessurier for inspecting the building and actually taking action to correct the issues.

[@jerardosalgado4506]

But the corner winds wasn't even an issue or a design flaw, and was accounted for by LeMessurier

[@markzeuslim]

@@jerardosalgado4506 exactly, right? As I see it, because of her that the engineer saw the actual flaw. But the flaw she noticed wasnt the real issue. So I dont think she has to take credit, right?

[@johneyon5257]

Hartley deserves some credit for anticipating LeMessurier in her concern for the quartering winds - even tho both have been proven wrong by a recent re-analysis of the wind loads using modern technology - the building is now extra-strong btw - the student whose phone call influenced LeMessurier is Lee DeCarolis - Hartley never spoke to LeMessurier

[@kiranoel49]

I remember my professor telling this story in my structures class in architecture school :') It was really cool going through the calculations to come to the same conclusion as Diane did. Needless to say... I made sure I did my homework thoroughly from then on.

[@frankmark787]

the problem wasn't structural though. she just alerted the engineer to go through the exzcution reports and he found out about the cheap bolts.

[@kiranoel49]

@@frankmark787 yes you're right. my structures prof framed the story in a way as a lesson on how something as innocuously simple as a bolt can have an aggregate effect on the overall system (also how important a good contractor is to a project). after all, structural systems are only as good as the tectonics of how their materials are joined. also, we focussed more conceptually on the added load at the top of the skyscraper and how it factored into calculations with the horizontal wind forces to test the integrity of the system.

[@kiranoel49]

the fact that wind forces had only been calculated in perfect cardinal directions was conceptually a major flaw in the integrity of the building's structure because real wind doesn't always work that way, and as a general rule, we want to design with the worst conditions in mind.

[@skya6863]

@@kiranoel49 normally with buildings that are supported in the corners the worst scenario is when the wind is blowing in perfectly cardinal directions

[@mrdobika4635]

that's why in software development a code change has to be always reviewed by someone else from the team

[@hamentaschen]

"The sea was angry that day my friends, like an old man trying to send back soup in a deli."

[@letsburn00]

And I looked Into the analysis and pulled out the calculation... *pulls out a bolt* "THAT A M20?...A BOLT IN ONE."

[@user19324]

I work in this building right now! I had heard this story about a city skyscraper and had no idea it was my building...

[@limerence8365]

Hartley's concerns were not about the mass dampener but the base of the building. If the power was cut and there were strong side winds, the building had more structural integrity than if the winds came from the corners. The dampeners main goal was to combat strong side winds. If the power was cut, if the bolts were weak, and if there was incredibly strong winds, the building was more likely to be pushed from the corner than the side, simply by how the base was built. That was Hartley's contribution, not just spurring the engineers to discover other faults.

[@whatsupgeek9608]

The greatest discoveries come from the simplest questions.

[@vitorfrancisco7726]

So true!

[@SATYANSH]

_Homework is important, but Ted-Ed notification is importanter_

[@seventeencarattrash]

Importantest*

[@justabotatthings.1039]

and worth it~

[@babamcrib]

Yes

[@sonofben3322]

@@seventeencarattrash importanterest*

[@MadMadOne]

I love it when the government works with companies in secret, but a speeding ticket is public information.

[@deanab-se5op]

This animation is on another league. 👁️👄👁️

[@thisisausername4459]

I literally watched a video about this today - wonderful timing! Diane surely saved many lives

[@squeaksquawk4255]

Last time I was this early the only skyscraper wsa in Giza.

[@seventeencarattrash]

Me taking three whole minutes to figure out what that meant: 👁👄👁

[@siesta7520]

wha-?

[@enjybadran7876]

You mean when you were a kid there was less skyscrapers than now

[@shawnebk]

www.youtubegas.com/watch?v=zipzip12

[@Arunabhh]

kzbin.info/www/bejne/b3q0h5ioqM6ehK8 ❣❣❣❣💯💯

[@johnnywasabi8710]

Ted you guys are amazing and make learning fun. You are the only channel that keeps me invested without being bored

[@AyratHungryStudent]

I was trapped on the 50th floor of 55 Water St building in Manhattan during hurricane Sandy. I felt like I was on Titanic, the building was swaying to the point it was noticeable and the metal construction was squeaking loudly. One of the reasons I left NYC.

[@feyh]

"Ok, I know that you are thinking" "OH NO" "Will the tower of pizza fall?" "Ah... Phew! Yeah, sure, totally what I was thinking"

[@claradipaolo571]

It’s the leaning tower of piza not pizza. Piza is the city in Italy where it is located.

[@feyh]

@@claradipaolo571 I know, blame the autocorrect. Or maybe my desire to eat a pizza right now.

[@claradipaolo571]

I think the second one is even more understandable than the first.

[@EmonEconomist]

@@claradipaolo571 It's Pisa, not Piza.

[@claradipaolo571]

@@EmonEconomist Double autocorrect lol

[@rosieg6989]

Thank you Ted-Ed, we covered this in class today and I got to explain the whole topic before the teacher even went over it.

[@fmailscammer]

I love these videos, its so relaxing to watch them and learn

[@seventeencarattrash]

A topic I didnt know I needed to know but learned wholeheartedly

[@vg666]

So Hartleys concern with the wind was not the problem, it was just that the construction people didn't weld the bolts (like they were supposed to do).

[@foxbatmc8457]

No the building needed reingotcements

[@johnathandoesemire2744]

Correct, the real problem arose from design changes (using bolts instead of welding) that were not communicated to the engineer.

[@johneyon5257]

don't be misled - using bolts instead of welds was approved by the engineering team - LeMessurier says they were authorized to do so - he wasn't unhappy when he learned about the change - until he recalculated the wind loads and grew concerned about the quartering wind loads - and realized the bolts were designed to meet the lesser loads originally considered - and that there were fewer bolts than he thought needed - i should add that his concern included the disabling of the damper by electric outage - causing extreme wind loads however - a recent e-analysis of the wind loads on the building using modern technology showing the quartering winds were not the threat Hartley and LeMessurier thought - and the original building may not have collapsed after all - the structural design still needs to be re-analyzed to be sure

[@danielf986]

This type of animation is pretty awesome! Please more of this!

[@rameshm9032]

Read about this years ago happy to see the animations.😀

[@thebakedfruit8850]

The KZbin algorithm has dark humor…

[@brandonf1260]

I don't understand what you mean by this comment?

[@brandonf1260]

NVM I REMEMBERED

[@brandonf1260]

@Sassy Sim the Florida building collapse

[@charlesloftin8768]

I found this by searching the archive but still it's a coincidence it was made around the same time. Before the incident if I'm not mistaken

[@aur9035]

@@brandonf1260 i love how you type ur texts

[@pepigeon8040]

Love the animation as always!

[@riddhipaithankar8047]

the quote called out so many of us...

[@aaronstanley6914]

Best version of this story I have ever heard

[@momowithnono]

I have seen my fanarts and many videos are not being credited I feel that how Hartley felt because this has happened to me to.

[@posthocprior]

There's a logical jump from Hartley's finding about corner winds to the bolts. The two aren't directly correlated. If the architect of the building never credited Hartley, how does one know that it was her discovery of corner winds on the building that was the cause of the discovery of the problem with the bolts?

[@johneyon5257]

LeMessurier directly credited a "guy" (see the video of his 1995 lecture at MIT) - an architectural student who called him to discuss the building - after that call - LeMessurier was moved to check the wind loads - and then to compare his new results with the actual structure - when he realized the bolts were probably too weak and too few recently - the student revealed himself - Lee DeCarolis (now an architect in New Jersey) was the student whose phone call prompted LeMessurier to recalc the wind loads - that led the engineer to become concerned about the bolts - that led to the multi-million dollar reinforcement however - a recent re-analysis of the wind loads on the building using modern technology showing the quartering winds were not the threat Hartley and LeMessurier thought - and the original building may not have collapsed after all - the structural design still needs to be re-analyzed to be sure

[@Plantpuffbaby]

Well, this is ironic now isn’t it?

[@radhakrishn9341]

Thanks for this😊

[@kl4pp3d_78]

Watching ted-ed is as smooth as mining sand with an efficiency V and beaconed shovel.

[@foxbatmc8457]

Haste 3

[@Yusuf-ke5iu]

Literally copied and then you added words.

[@nurozfajris338]

when someone ug's thesis has saved many lives, my ug's thesis only saved my marks 😥

[@anthonyz9321]

Absolutely awesome.

[@rushilpatel7418]

*Her homework had saved lives* Every SchoolTeacher: This is the moral of the story

[@snorefest1621]

I read an article about this in New York Times two years ago. I'm so interested in this that I saved the article

[@vasurvawadajkar]

Nice video you guys!

[@m.islamnafees5770]

Love Alex Gendler's lessons

[@sutats]

It's always good to have an open mind.

[@pretty.cool.sports]

I just happened to learn about this in science a little while ago.

[@atikahrostam5778]

this gave me chills

[@justalilblobcom]

I love the animations and the never ending puns! xD

[@NihilistEmier]

Hey there!

[@dynamosaurusimperious6341]

Good video about Skycarper again.

[@adityachk2002]

The last line was lit

[@pimlico3225]

Wait, was the Chief Architect's name Le Mesurier as in "the measurer" in French? Was just watching stand up where the comic made the point that most times you'll find people have careers that match their name. Just interesting.

[@lynnroney1234]

I'm not an engineer, but when I heard and saw "bolts" I loudly said "What? Are you crazy? That's what we have highly skilled and experienced welders for". I watched a humongous addition to the hospital I work at get built from the ground up. Welders, welders welders all over the construction of the skeleton. Like I said, I'm not an engineer, but with all the issues that seemed dangerous in and of themselves, I wonder, if the "perfect storm" so to speak, of all those elements coming at once and the 4 ton "leveler" at the top having been rendered inoperable by a lightening strike, would that have been enough to also make the building "top heavy" and that makes it even worse? Is there someone out there who could answer my question? Just my curious little mind at work, but I'm just one of those people who needs to have an answer. I thank you in advance.

[@sksanjeev1106]

I love this channel ❤️❤️

[@55455]

i love that i already knew this... from a ted video years ago

[@kirbymarchbarcena]

It was a long one but at least Hartley got the respect and recognition she deserves

[@Arunabhh]

kzbin.info/www/bejne/b3q0h5ioqM6ehK8 ❣❣❣❣💯💯

[@johneyon5257]

maybe someday the architectural student that LeMessurier spoke to by phone - which prompted LeMessurier to recalculate the wind loads - and spurred him to get the building reinforced - gets the recognition he deserves - his name is Lee DeCoralis - he is now an architect in New Jersey - but he only revealed himself since he learned about the re-analysis of the wind loads on the building - concluding that the concern showed by Diane Hartley and later LeMessurier - was misbegotten - the re-analysis used modern technology and showed that the quartering winds were not the threat those 2 thought they were - would the building have withstood the high winds like the ones carried by hurricane Ella during the reinforcement - a re-analysis of the original design against the new wind load info would need to be done to be sure

[@akshada01akki]

I would love to watch a movie based on this amazing story.

[@benjaming.8368]

Some people spend their lives nothing but studying to perform exceptionally. It is people like this man that discourage future talent by taking them for granted.

[@MRMOH-st6pr]

the last time I was this early TedEd still hearted the comments

[@sobhaks7231]

They still do

[@lubu682]

oh wow! thank you!

[@thankswillie]

would really like to hear from one of the welders on that repair job

[@FinancialShinanigan]

Hope she got an A++ for her thesis

[@Cybernaut551]

It's great that this was made.

[@pragha_]

It's been a long time since you made videos on Space and Physics. Please make one...

[@dynamosaurusimperious2718]

Epic video about Skycrapers again. Ted-ed

[@josephgodbey5490]

this is the best ted ed video

[@Amitdas-gk2it]

TY ☺️

[@anonymousdude2550]

TED Ed is the pool of countless genres

[@_Breakdown]

3:06 - - never knew there was a mass damper - - or that it would be inoperable if the power goes out.

[@kingshill96]

@ted-ed, Roman Mars podcast 99 Percent Invisible brought this story years ago. I am sure you would have drawn inspiration from this podcast in the script writing for this. In any case they deserve a shoutout for that podcast episode, it's fantastic!

[@hambos]

Ok but the music in this is extraordinary

[@thunderlol99]

Thank you so much Ted-Ed for enriching our lives with these interesting videos, that most of us did not even know. Words cannot describe what you did for us. My special gratitude goes for the animators, researchers, linguists (Excellent language).

[@eronpetri1049]

It is just me or the chief engineer looks like a James Bond villain

[@DrRank]

The narrator is the Demon of Reason's voice actor! He's doing regular TedEd videos now!

[@DrRank]

@Ted Ed You nearly had me there.

[@Arunabhh]

kzbin.info/www/bejne/b3q0h5ioqM6ehK8 ❣❣❣❣💯💯

[@alparslankorkmaz2964]

Nice video.

[@tobias2688]

So if I understand it right, the issue wasn't Hartley's discovery but the fact that the construction wasn't according to the engineering plan.

[@johneyon5257]

the video is too brief to give the entire story - i see a lot of misinformed comments here - but you may be right - if they used welding instead of bolts - it may have been fine - but it also may have been fine with the bolts - a recent e-analysis of the wind loads on the building using modern technology showing the quartering winds were not the threat Hartley and LeMessurier thought - and the original building may not have collapsed after all - the structural design still needs to be re-analyzed in light of the new wind load numbers to be sure

[@GM-zy3xj]

They should have credited Diane Hartley for her work and her warning.

[@johneyon5257]

she has been getting alot of mention lately - altho some of it is misplaced - she wasn't the student who LeMessurier talked to over the phone - it was a guy called Lee DeCarolis - that call got LeMessurier recalculating wind loads - leading him to worry about the quartering wind loads - and that led to the reinforcement of the building - Diane Hartley in her thesis also was concerned about the quartering wind loads - however they both may have been wrong to do so - a re-analysis of the wind loads using modern technology has contradicted them

[@momowithnono]

How can I contact the editor/animator? He/She is literally an amazing person

[@boy638]

They always include it in their description.

[@momowithnono]

@@boy638 but there are bunch of people not specified

[@boy638]

@@momowithnono Then I would contact the animation studio for that info.

[@raygordonteacheschess5501]

I used to sakte under the construction maze they had up while fixing the building.

[@idontremember8021]

OMG imma do my assignments and projects too . what if it is threat to people ? brb gotta do my home work . thanks ted ed .

[@HelgaCavoli]

If "the article failed to give credit where it was due" how do we know about it today that she was the one? Wouldn't even her papel be proof enough? To go to the article people and ask for a retraction or something?

[@roscoejones4515]

Later studies (2019) have shown the building was actually safe as built, even with the bolted beams.

[@marcusmitchell6220]

Question everything!🤔

[@sushikazuki5945]

Oh hey they talked about this on Well There’s Your Problem

[@snidhireddy5896]

Ted-ed is the reason that makes my regular classes seem boring

[@benrozner3353]

is that the voice of demon of reason!? i love that voice(and the character)

[@alessiabondoc8641]

Demon of Reason voice? Love it

[@zerocell2657]

Ok, but she didn't really figure out what was wrong. She had a concern, and the architect assured her it was accounted for. The concern just happened to make him go back and check, where he found a different problem that he had no knowledge of or input on.

[@thefandombard4774]

I should send this to my CE professor....

[@naclvine]

I just watch these because it’s relaxing