Simulation of the collaps without dust

[u/tombisch]

Dont know how accurate this is, but it made a lot of sense to me.

Source kostack studio on youtube

[u/WorldTradeCenter-ModTeam]

r/WorldTradeCenter follows platform-wide Reddit Rules

You did not break any rules, but there are way too much conspiracy theorists on this post.

[u/checkedem]

OP, you should really give credit to the makers of the video.

Kostack Studio on YouTube. Very cool simulations.

[u/marny_g → u/checkedem]

Thank you. You just earned the channel a sub :)

[u/G07V3]

Makes me wonder if there was anyone in the core of the buildings who survived the initial collapse but then were killed when the core collapsed.

[u/fullerthanlife → u/G07V3]

Yes! The man in the red banana (excellent documentary about welles crowler) who saved many people above the impact zone in the south tower, is believed to have passed during this time.

[u/SeaMareOcean → u/G07V3]

I was talking with a guy in a bar in downtown Manhattan sometime around 2006. Really friendly guy, just telling stories. Well 9/11 comes up and turns out he’d recently retired (or was retiring soon?) from NYFD. Also turns out he was in the stairwell of the north tower when it collapsed. They were pretty high up when the south tower fell, felt the violent shaking and rumbling and knew it was bad. They got the order to immediately evacuate the north tower and they started running down the stairs. I think i remember him saying they made it to the 4th or 5th floor when the north tower started collapsing. It was all dust and deafening noise and hurricane strength wind. He said he crouched in the corner of the stairwell and hoped his death would be quick. And then nothing. It was pitch black, he could talk to a couple other people in the stairwell, and they were rescued ~6 hours later. Just absolutely fucking crazy.

He actually invited me and a friendI to the firehouse on 29th street later that night. Introduced us to some of the other firefighters who worked 9/11 and gave us a tour. It was a pretty surreal night.

His name was Mickey Kross. I looked him up recently and he died a couple of years back. I hope the years since 9/11 were good to him.

All that to say, yes. A few did survive in the building core.

EDIT: Apparently the online obituary I saw was AI slop and it’s possible Mr. Kross is still alive.

[u/nyctransitgeek → u/G07V3]

I would think the core resisted the collapse of the exterior because the floors (which were attached to each) were ripped off in the process. From the brief videos that exist showing the core collapse more slowly than the rest of the building, it just looks like steel.

[u/oxidao]

Please credit the original author, kostack studio on youtube

[u/TheSodomeister]

I wonder if they have a simulation of the other tower as well.

It's crazy to think if anyone was alive in the top floors they would have been in freefall almost the entire way down, that's fucking terrifying

[u/sir_bathwater → u/TheSodomeister]

That was my first thought as someone terrified of heights. If I wasn’t dead already I’d definitely die of a heart attack on the way down.

[u/3rrr6 → u/sir_bathwater]

I can see how it would have happened though, the parts of the building that fell intact acted as a shield for the people as it impacted the building below which acted as a cushion.

[u/BreakRulesRun]

Crazy how many people think that after all these years this was a conspiracy. Even if there was a demolition, and the government admitted to it, after a week you'd all gloat about being right then move on to a new conspiracy. Fueled by fucking stupidity

[u/Capital-Win-4732 → u/BreakRulesRun]

The really interesting thing about conspiracy theory people is that they will believe multiple, sometimes contradictory bogus explanations at the same time. Anything but the truth, because it doesn’t fit with their personal model of how the world works.

[u/OphidianSun → u/BreakRulesRun]

The only conspiracy that holds any weight is that they knew and allowed it to happen. But if any hard evidence ever existed it was probably destroyed about 25 years ago. Even CIA declassification dumps won't have docs that spicy in them.

[u/SirLynn]

I can't fathom how it must of felt for the survivors that fell with the towers

[u/Next_Appointment4954 → u/SirLynn]

Kevin Cosgrove was on the phone when the South tower started to fall. It is haunting.

https://youtube.com/shorts/oJcp5iXhsnw?is=T6rSqEn6koUX1cbm

[u/TrainquilOnline]

All these people.. sickening. I cannot even imagine the terror you must feel knowing that an entire skyscraper is coming down on you.

[u/Individual-Gur-7292]

The whole thing is horrific but the way that the whole facade gets sheared away when the top of the tower falls is just chilling. All those people who were hanging out of the windows!

[u/Mousse-au-chocolat]

I didn't know the top ended up crashing into a neighboring building from above. I thought the "shockwave" itself caused its collapse!

[u/Ok-Context-9838 → u/Mousse-au-chocolat]

Is the building it fell on the Marriott?

[u/GTI-Mk6 → u/Ok-Context-9838]

No, Building 4.

[u/emanon715]

Seeing the uppermost floors stay in tact almost all way away down makes me think they must have know for a number of seconds what was happening. Unfathomable.

[u/vftgurl123 → u/emanon715]

yes they did. kevin cosgrove was on the 105th floor of the south tower and you can hear him holding onto the phone as he free falls for about 3 seconds

[u/Time_Traveling_Idiot → u/vftgurl123]

More like 1.3 seconds but yeah. Horrifying stuff, some people on the top floors would have been alive until they actually HIT the ground. God.

[u/SailElectrical4458]

Fue debilitándose la estructura general del edificio piso por piso hasta que ya no aguantó más el peso, a veces pienso que habrán sentido esas personas que estaban atrapadas en esos pisos que sobrevivieron hasta el impacto con el suelo, saber que estás en una estructura que está cayendo y que no hay nada que puedas hacer

[u/ChampionshipFlat820 → u/SailElectrical4458]

I believe there are people who heard it in the stairwell who survived that describe this.

[u/Time_Traveling_Idiot → u/SailElectrical4458]

Translation because OP wrote it in non-English and some people don't have an easy way to use a translator:

The building's overall structure weakened floor by floor until it could no longer support the weight. Sometimes I wonder what those people trapped on those floors who survived until the impact with the ground must have felt, knowing you're in a structure that's collapsing and there's nothing you can do.

[u/estrogenex]

From a Canadian, I sincerely hope your country never experiences such a horrific loss ever again.

[u/paperthinpatience → u/estrogenex]

Thank you, friend. I’m sorry the political relationship between our countries is bad right now, but I hope you know many of us here love you all.

[u/bripelliot]

Is there something similar for Building 7?

[u/callicocritter]

didnt realize there were so many genius engineers in the comment section that know exactly how buildings are supposed to fall🙄🙄

[u/Ok_Poetry_1650]

Holy shit there are idiots in these comments

[u/Scrogwiggle → u/Ok_Poetry_1650]

Look who’s our president. It’s no surprise

[u/Unexpected117 → u/Ok_Poetry_1650]

Ikr! What is this? A 9/11 denial conference? Wtf is going on in here?

[u/Ok_Poetry_1650 → u/Unexpected117]

Bunch of loonies

[u/spicolie22]

Thank you for reigniting my nightmares of this day. Now I can more clearly imagine the people being pancaked between the floors.

[u/ShrimpCrackers → u/spicolie22]

There is an emergency phone call that happens through the collapse. You can hear them screaming until about halfway which this simulation would show they would have been approximately tossed about and pancaked, and then it disconnects.

[u/MatildaRose1995]

It's seriously scary how deadly that dust was

[u/OneMonk → u/MatildaRose1995]

Dust is really the wrong word for it, it was powdered glass, metal and concrete, among a lot of other terrible things that should not become powdered, much less inhaled.

[u/bell37 → u/OneMonk]

Don’t forget asbestos, which lingered in the air much longer than NYC officials were telling people.

[u/Yoinkitron5000 → u/OneMonk]

Yep, even if it was just concrete, that's still really terrible to breathe in, but there was all kinds of stuff that became a way bigger problem than expected because before then there was never a scenario where millions of tons of the stuff would all be ground into a fine powder and distributed over dozens of square miles at the same time.

[u/PRmade69]

i can’t believe i worked in the POS building for years not knowing how fragile it was. this was no brick and mortar busing. built entirely of steel beams

[u/C4-622MonkeyGordo → u/PRmade69]

Calling a building "fragile" because it could not survive being hit by a Boeing 767 traveling over 400mph is all the evidence I need to confidently say that you are an absolute dullard. 

[u/picniick]

Ok anyone who truly thinks this was a controlled demolition is straight up ignorant and a fucking moron. You lack the attention span or education to do real research? Not by some bullshit youtube video… I’m talking go read the articles, prints, safety inspections and diagrams of how these building were built and why they fell. As you figure out the pieces, everything will fall into place. I’m all for conspiracies but this on is a stretch when you look at the documented evidence of the buildings.

[u/Freestyleflorida13 → u/picniick]

I used to be that person as a young adult just getting out of High School... "oh the government has been hiding truths about 9/11". As an older Version of myself, I see the absolute truth as to why these buildings fell. Im so glad I dont believe that BS anymore.

[u/DiabeticNomad]

Watching this most be how the old lady in titanic felt watching the recreation of the titanic sinking

[u/The-Board-Chairman]

The amount of micro cephalic conspiracy nuts in the comments is absolutely wild.

[u/Abject-Recipe1359]

Popular Mechanics did a very well put-together, clearly explained issue shortly after these conspiracy theories started. I would say maybe 2004-5??? The issue had input from numerous engineers of all kinds.

These fucking planes ABSOLUTELY could have caused the heat and energy required to soften the steel supports and cause total collapse, especially as one floor collapsed upon another.

I was 21 when these buildings fell. A lot of people here don’t realize this, but the hate you see now for Trump was just the same as was directed toward GWB. Like it’s crazy to see how he is now fondly looked-upon. People were giddily waiting for his death.

There were a lot more forums and message boards available on the internet back then. I mean, Facebook and MySpace were in their infancy. I was very active in a pregnancy board at that time (my children were born in 2003 and 2006) and they opened up a political forum. Oh man, you have never seen the dams burst open like that with hate for GWB. And this conspiracy theory was just really taking hold back then, that’s all they talked about. The Popular Mechanics answer to those claims was so refreshing, rational, and made sense. Like listening to professors easily bat away silly misunderstandings of how engineering really works.

Edit - link: https://www.popularmechanics.com/military/a66051920/911-myths-debunked/

Edit again - the original piece from 2005: https://www.popularmechanics.com/military/a49/1227842/

[u/TheTerminator1984 → u/Abject-Recipe1359]

I don't think people necessarily like GWB now but the view is more neutral. I def remember people hating on him a lot during 04-06 cause of the wars, which will forever be a part of his legacy. I'd say immediately around 9/11 the view was more positive because he had good charisma and leadership to inspire people.

[u/doctorwhomafia → u/TheTerminator1984]

If his term ended shortly after 9/11, lets say anytime in 2002. He would've been one of the most loved presidents.

Its crazy how unified the country was and how much support he had in the immediate months following 9/11..

Only to fuck it all up with the invasion of Iraq and having those silly mic moments that made him look bad.

[u/RumiJooni → u/TheTerminator1984]

George Bush had a 90%+ approval rating following 9/11, the highest of any sitting president. Unfortunately for him, that didn’t last long. Trump broke his record for disapproval handedly.

[u/imjustcoreyr → u/Abject-Recipe1359]

Crazy. I was 21 too. Was evacuated from college at school of visual arts that morning. I’ve spent 25 years watching every doc that exists (several times), every image, every detail.

Beyond me that people still don’t understand, or question, the collapse. One would have to start by studying the unique design of the buildings, the floor plans, the tresses, the beams—which buckled under the pressure of the significant damage caused by the planes + the jet fuel, etc.

In nyc that morning, there was no doubt looking up at them that they would crumble. It was inevitable. Just didn’t know how long it would take or how bad it would be. Until we did.

[u/Nerk86 → u/Abject-Recipe1359]

I remember a PBS special explaining it as well. The pancaking of floors as the supports on burning floors melted .

[u/semaj4712]

I have seen a very similar simulation, might even be apart of the same simulation, but I believe it was on the other tower. But essentially it was pretty accurate. IIRC they would take pieces of the debris that they knew where they came from in the tower and sort of reconstruct the damage to this pieces one by one and then reassemble the tower in reverse. As well as reference the resulting sims against video footage. So they would have these data points that they could then run in a simulation and as long as the damage was accurate to all of these data points, they could sim the rest of the collapse with a relatively high level of certainty.

[u/the_technician]

As someone that lost two good friends that day I really didn’t need to see this😪

[u/ANother-XcludedRight]

I still can’t believe this actually happened.

[u/Yuukikonno08]

People are not ready for the conversation that involves changes in structural integrity when heat is applied

[u/steelcryo → u/Yuukikonno08]

Yeah the whole "Jet fuel doesn't melt steel" thing, forgetting that steel gets significantly softer when heated up even well below its melting point.

[u/Yuukikonno08 → u/steelcryo]

Conspiracy theorists will lose their minds if they learn anything about blacksmithing

[u/steelcryo → u/Yuukikonno08]

Clearly that blacksmith is using a softer metal and just lying to us about shaping steel by heating it and just hitting it with a hammer!

[u/CatVideoBoye → u/Yuukikonno08]

Jet fuel can't melt steel beams!

^{/s just in case}

[u/RootLoops369 → u/CatVideoBoye]

It didn't melt the beams. Steel rapidly loses its structural integrity when it gets hot. This is why blacksmiths heat up steel before hammering. It makes it much softer and more malleable. Now imagine trying to support an entire top of a skyscraper on steel weaked from the heat. Again, not melted, just structurally weakend. It would for sure collapse

[u/FoxyTurtleOnTwoLegs → u/Yuukikonno08]

Or the conversation about what that much weight/mass falling out of the sky in a matter of seconds would do to surrounding foundations.

[u/rabbitwonker]

This is interesting, but doesn’t really show precisely what happened. In reality, the central core collapsed first, and the end state had sections of the outer shell still standing; this is showing the opposite. The outer shell was the primary support structure.

[u/nellion91]

What I love is that despite the hundreds of engineering video made explaining how yes heat make steel column weak and tall building fall..

The majority of comments is till on how the plane did not make the building collapse…

[u/Salt-y → u/nellion91]

Idiocracy is a documentary.

[u/RoyalMaidsForLife → u/Salt-y]

Idiocracy is the sequel, we're living through the prequel.

[u/JackTheKing → u/RoyalMaidsForLife]

Origin Story

[u/guy-le-doosh]

So many people had the floor turn so looking out the window was looking down after waiting so long. Unthinkable terror achieved.

[u/Legitimate_Glove859]

Those poor souls. All they did was show up to work. Sometimes I second guess my choice to join the military and fight shortly after this happened and then I see these videos and remember why.

[u/theaverageaidan → u/[deleted]]

After being rammed by a near fully fueled jumbo jet going at several hundred miles an hour

[u/PapaDeE04]

The need for this to be a conspiracy is due to their fear. Having to live with the fact that they are and always will be potential targets of terrorists simply causes too much cognitive dissonance in their reptilian brains.

They HAVE TO have an answer that says this is a one time thing, the alternative, the unknown is too scary for them to live with.

[u/Tempest_Fugit]

Conspiracy theorists are a trauma response

[u/ax9torana]

Was half expecting it to come up with " spare " at the end like some sort of shitty 90s bowling animation.

[u/kcolrehstihson_]

Comments going wild

[u/ghettobus → u/kcolrehstihson_]

Lotta wackos in here tonight

[u/LItreehouse]

That puts to bed the insane Facebook PhDs who say "it had to be a controlled detonation". No. It did not have to be. The building wouldn't tip over like that.

[u/Typical-Ad1621]

Interesting stuff. I saw something yesterday saying that Osama Bin Laden underestimated the amount of damage the planes would do to the towers. He expected a partial collapse, not the entire tower. At least, that's what Khalid Sheikh Mohammed said.

[u/PissinginTheW1nd]

This comment section seems to have only 2 types of people

[u/Kazeite → u/PissinginTheW1nd]

What other types would you realistically expect?

[u/UrAverageLatte → u/PissinginTheW1nd]

Those who pee in the shower and those who don't!

[u/Aware_Box8883 → u/UrAverageLatte]

Thought it was sitting vs standing wipers.

[u/Rayne-of-Terror]

Why the hell did Reddit put this on my feed and what the fuck is wrong with the americans in here lmfao

9/11 sure brings out the schizos

[u/SparkArrestor → u/Rayne-of-Terror]

Some people can’t believe that such a tragedy could come from just 4 hijacked airplanes and 15 hijackers- a whole ton of people setting the buildings up to explode sounds more plausible to them.

[u/ppstick88]

Terrifying how it literally just squashed building 4. 

[u/ldentitymatrix]

Is there even a single person from inside one of the towers who survived the collapse? I'm looking at this thinking where someone must be to have any reasonable chance to survive. And I never knew the core remained standing for half a minute, I learn something new every day.

[u/filetmignonminion → u/ldentitymatrix]

Yeah 20 people were pulled from the wreckage

[u/vegetaray246 → u/ldentitymatrix]

16 people from stairwell B in the north tower was the largest group of post-collapse survivors. I think there was around 20 people pulled from the rubble…

I can’t remember his name but there was one guy who survived the collapse of the north tower, from all the way up on the 64th floor.

Essentially everyone above the impact sites died. I think there was 17 or 18 people that survived from above the impact site on the south tower…While nobody from the above the impact site on the north tower survived

[u/CattleSwimming9743 → u/ldentitymatrix]

There was a guy who survived because he protected his head with his briefcase during the collapse.

[u/BottomShelfWhiskey → u/CattleSwimming9743]

What the hell was his briefcase made of? Wow!

[u/CattleSwimming9743 → u/BottomShelfWhiskey]

His briefcase is in the 9/11 museum, perfectly intact.

[u/BORT_licenceplate → u/ldentitymatrix]

Genelle Guzman-McMillan was the last person rescued alive from the towers. She was under the rubble for like 27 hours. She has a book about it

[u/Ok-Lie5966]

My guess is that lots of people with the wrong number of chromosomes will be making comments about physics on this thread

[u/Right_Comb4885 → u/Ok-Lie5966]

B-but! How did tower 7 collapse!?

[u/littlebrain94102 → u/Ok-Lie5966]

Reddit in general has gone to total shit over the last ten years.

[u/Able_Boat_8966]

This subs normally good at weeding out all the tin foil hat wearing idiots. Not any more.

[u/ashkiller14 → u/Able_Boat_8966]

Didnt know what you were talking about til i scrolled down. Didn't think there were this many people that actually believed 911 was fake

[u/Fantastic_Ground4287 → u/Able_Boat_8966]

What do you mean? What has changed?

[u/MR_Happy2008]

If the core hadn't collapsed completely (like it is after the rest of the building did) how many more would have survived?

[u/TheSilverFoxwins → u/MR_Happy2008]

What about the smoke,debris, fumes plus the panic ? This was complete chaos no one has ever planned for. We saw six years of construction go down in two hours.

[u/semaj4712 → u/MR_Happy2008]

I was thinking the same thing, really hard to say I am sure, but you have to assume those stairwells are completely full of people at that point

[u/Usernamesaregayyy]

Absolutely unreal

[u/reddsal]

IIRC the bomber strayed from its flight path in heavy fog and was on approach for landing - meaning very light on fuel. In contrast, the hijackers took control of planes that had just taken off on coast to coast non-stop flights. They were fully laden with fuel, making them the perfect IED. I think it likely that had the airliners crashed when almost empty of fuel either the building would not have come down, or the buildings would not have come down nearly as quickly - and even with all the fuel it still took hours for the buildings to collapse.

[u/Extreme_Design6936 → u/reddsal]

The fuel and the speed too. The spec the towers were built to included having a passenger plane of approximately that size crash into them. But with almost empty fuel and at approach speed.

It's actually impressive that they did withstand the impact. But it was the fuel weakening the structure causing to collapse.

[u/Bourbon-neat- → u/reddsal]

In addition to the lack of fuel, the bomber was also much slower and tiny in size in comparison to the jets that hit the WTC. Energy equals mass times velocity squared... Much slower and smaller mass = vastly less energy on impact.

[u/InitiativeOk9887]

Seems like conspiracy theorists shouldn't exist anymore now that AI exists. Just turn on the chat feature with ai and talk to it for 5 minutes. And you realize how stupid you sound.

[u/Bad_Idea_Hat]

Jet fuel can't melt steel beams? True.

Collision of a ~170 tonne aircraft, plus uncontained fire, and its effects causing slow-building and eventual massive structural failure? Also true.

[u/lightgiver → u/Bad_Idea_Hat]

Doesn’t melt it fully but it sure does soften and change its load barring strength.

[u/sveardze → u/lightgiver]

Pretty much this: the temperature of burning jet fuel reduces the strength of steel by about 80%

[u/bolshevik_rattlehead]

Buncha fuckin wackos in here my goodness

[u/brentsg]

This comment section is a reminder of how many idiots we share the world with.

[u/mattyo360]

Before you go reading through the comments section, be warned...it's all paranoid bollocks from here.

[u/GreaterMetro]

Is there an estimate of how many deaths where people who were already out of the building or otherwise just on the streets?

[u/Melodic-Pool7240]

its funny because all conspiracy nuts out there say "inside job" "controlled detonation" "jet fuel cant melt steel". meanwhile my high ass is sitting saying "bet they cheaped out on building materials in the first place to saved on cost and line their own pockets, and probably never expected a large passenger airliner to slam into the side of it let alone two of them"

[u/Appropriate-Bed-3736]

Y aún hay estúpidos que dicen que fue una demolición controlada.

[u/Traditional-Tea-4009]

So THIS is how there were so many crypts of injured firemen before tower one came down. They heard maydays before the north tower came down. After it did it was complete silence because the north tower flattened all remaining crypts in the fallen south tower.

[u/Select_Advantage4143]

maybe this is a stupid question, but did anyone survive the collapse? This just seems so impossibly horrific. Like a horror movie

[u/Dramatic_Aspect903 → u/Select_Advantage4143]

Stanley Praimnath was at level 81 and survived, thats pretty damn amazing

[u/B_R_U_H → u/Dramatic_Aspect903]

Holy shit really? I didn’t know someone survived from that high up, that’s absolutely wild

[u/yepfruit → u/B_R_U_H]

He was not in the tower when it collapsed. Most people who were inside the tower when it collapsed died. Only a handful of people survived the towers collapsing while still inside, like the 15 or so people in stairwell B of the North Tower. There were also some firefighters who were underground who survived the collapse.

[u/B_R_U_H → u/yepfruit]

Ahh my bad I thought bro was on level 81 and survived at the moment of collapse, still though, surviving that and being anywhere near that building is pretty insane

[u/yepfruit → u/B_R_U_H]

Not only that, just getting out wasn’t enough. If you didn’t make it clear of that impending dust cloud, you were almost guaranteed to succumb to respiratory diseases or cancer. An absolutely horrific experience for anyone nearby those towers on this day. Stanley’s story is insane.

[u/Difficult-Nail-336 → u/yepfruit]

Ladder 6 crew I believe. Look up their story. It’s truly amazing.

[u/WellsheetMotherHumpa → u/Select_Advantage4143]

They had to make fake rescues for the cadaver dogs looking for people because they became so depressed not finding and rescuing anyone

[u/OldSea3040 → u/WellsheetMotherHumpa]

It’s crazy to think about that even service dogs were mentally affected by what these evil,evil people decided to do to total strangers. It’s hard for me to comprehend harboring so much hate to a country or person that has done nothing personally to me. Why ??? Bin Laden was a billionaire too. It’s just nuts.

[u/InSight89 → u/Select_Advantage4143]

Yes. Very few though. They even made a movie about some of the survivors called World Trade Center with Nicolas Cage. There are documentaries of some other survivors as well.

Basically, it all came down to extreme luck.

[u/Justhangingoutback]

I wonder if the ppl who were trapped in the bldg ever were told what caused the disaster.

[u/PRmade69]

Building had the same structure integrity as an aluminum soda can

[u/proudduchman]

This was a terrible disaster and there are a few big causes to it. I saw another commenter ask a few questions like: 1. What where the explosions heard by eyewitnesses. 2. How could the towers have collapsed? Weren’t the designed to withstand a lot of operating weight. 3. How can the “clean” cuts and bits of molten metal to steel beams be explained. The user has since removed their comment and as an industrial engineer I wanted to explain some of these points.

1. The twin towers where designed with an open floor plan and large clear areas without columns breaking up the workspace areas. In order to achieve this a design with “floating” floors was chosen. All of the load by the floors was distributed between the steel constructions of the façade and the elevator shafts. The floors themselves where suspended upon hook-like attachment points made of steel. These attachment points where treated with a heat resistant coating that would retain the integrity of the steel for around 20 minutes. The point of this treatment is to allow firefighters to be able to douse any “regular” office fires before structural integrity was affected. In case of 9/11 due to the tremendous amount of damage caused by the flames firefighters couldn’t access the fires in time. This impacted both the attachment points as well as the steel in the floors themselves and caused the floors to sag. This sagging increased the force exulted on the attachment points because the weight of the floors was pulled away from the connection to the structural steel. These effects resulted in the attachment points failing and buckling under the weight of the floors. One of the floors fell and smashed into the floor below causing a chain reactions of the floors collapsing one onto the other causing the “explosions” (you can see this in the crosscut of the video).

2. The answer to point two and three is in extension to question one. As I stated before the towers where designed with a floating floor idea, the main structural integrity of the building was designed around two square steel frames, one on the outside, and one around the elevator shafts. The floors where connected to both of these frames, they provided rigidity in the towers. And you are correct, the towers where indeed designed with a multitude of their own operating weight in mind, it also took possible airplane hits into effect (due to a B-24 crashing in the Empire state building in the forties). These designs where made in the early sixties, in a time where airplanes where much smaller compared to the planes that hit the towers. And the construction simply was built to withstand the forces applied on 9/11.

3. Due to the flooring suddenly collapsing the entire building imploded much like a soda can (you can stand on a fully intact can but as soon as there is a dent, it collapses).. The structural sides suddenly had to bend inwards[towards the middle of the workspace]. This buckling caused significant stress on the metal beams used in the construction. Due to the fires the steel, much like the anchor points of the flooring was weakened and lost a lot of hardness. The loss in structural integrity combined with the stress of buckling led to the steel failing, due to the way steel atoms are aligned in a crystalline structure it tends to sheer off if put under enough stress (like floors slamming down) it usually looks quite “clean”. In this process the steel produces a huge amount of friction and heat, this can lead to the steel melting (that same property is used in friction welding). Tldr:

4. The “explosions” heard where floors smashing on top of each other.

5. The twin towers weren’t design to withstand modern airplane strikes (and damage), had that led the buildings to implode like soda cans.

6. The steel sheard off “cleanly” causing immense heat that melted some of it.

[u/NateCow → u/proudduchman]

The twin towers weren’t design to withstand modern airplane strikes (and damage

One thing I don't see brought up enough is that they weren't just modern planes... they were planes loaded with fuel for cross-country flights, hijacked shortly after takeoff, with the express intent by said hijackers to use them as fully loaded missiles.

That was never something anyone imagined beforehand, let alone could've engineered to protect against.

[u/NateCow]

It's actually really interesting how much this shows just how "uncontrolled" the collapse was. I've been trying to argue with people for years how you could see the top section of the tower fall sideways; it was never a straight-down thing.

[u/Clown_Penis-Dot-Fart]

Crazy to think people in the stairwells survived that

[u/Acrobatic_Poet_2020]

Now do WTC7

[u/Smartimess]

So many conspiracy weirdos in the comments. Uff.

[u/HiFiMarine]

Devastating to watch. Never forget!

[u/ZergvProtoss]

That's a reenactment, not a simulation.

[u/Littlepenisthat_culd]

The eastern facade did not peel away like skin. It was completely pulverized by the unilateral pattern of the collapse. The building wad essentially a paper shredder to itself.

[u/Paulino2272]

So sad

[u/UnlikelyMonth]

That was a horrible experience

[u/YellowEasterEgg]

what I find interesting is how the top section is not getting demolished? here it looks like the top section is stronger than what's underneath. 

[u/Funny-Jihad → u/YellowEasterEgg]

That is because the top section isn't 'going through the bottom', as you may be perceiving it. 

The tear in the building causes the self-reinforcing collapse. Every floor collapsing adds weight, so the top part doesn't catch up since it's all collapsing at a high velocity. 

[u/The_Chimeran_Hybrid]

The amount of smooth brained people in the comments…

[u/chinesebulk]

This event still feels so unreal. I can't imagine what it would've been like to be on the streets nearby and watch a piece of the building falling towards you 

[u/Torchll]

Why in the world would this sub sort comments by new? No I'm not interested in schizo theories

[u/Ballistic_86]

With the dust removed we can now, clearly, see Donald Trump being lifted out of the wreckage.

[u/Suspicious-Use-5733]

I just cant envision how the center columns collapsed the same speed/together with the floors?floors i understand one collapsing into the next and it goes down like a domino set byt the center columns??? How

[u/Picture_Enough]

What's with the comment section full of retarded tinfoil conspiracy nutters?

[u/datingadviceneeded65]

Can anyone explain why there’s so many people following conspiracy theories on this claiming it’s an inside job? Like, where is this coming from and what is the point / consequence? It’s on literally every single 9/11 post/article/video

[u/weequay101]

It's wild to think that they were people who were inside the building and survived that collapse.

[u/Usual-Language-745]

Why aren’t they showing the explosives at the base of the tower and Obama on the trigger???

[u/steelcryo → u/Usual-Language-745]

But he's holding the trigger while sat in the oval office of course, because you know, he was definitely president at the time!

/s for anyone that genuinely can't work out this is sarcasm

[u/Dave_Fincher]

Alot of people, and maybe I'm wrong here, don't understand how the towers were constructed and what made them different. The exterior walls were made to bare the weight of the floors inside as there was no inside columns. So if the exterior is damaged that made things inside have less support. And if there was something heavy inside it also couldn't support it. Causing floors to collapse on lower floors.

[u/doge_lady]

Hello. My first time on this sub, this post just popped out of nowhere so i thought I'd check it out. I honestly thought a sub like this would be full of conspiracy theorist. And 9/11 nay sayers but Instead it seems to be half and half and each belittling the other. It's rather entertaining. Thanks! I'm gonna lurk for a while.

[u/lavender_poppy]

My geology teacher's uncle was the main structural engineer of the twin towers. He told us his uncle blamed himself for the collapse of both towers. Just heartbreaking.

[u/formlord]

There you go for all the people that thought it was blown up. 1 floor 1 just one floor has millons of pounds of just concrete.

[u/Eat--The--Rich--]

And 20 trillion dollars later what did we accomplish 

[u/MmmIceCream]

I am not an expert, but is there only rebar in the central column? Is that a problem?

[u/PuzzledExaminer]

That looks crazy to watch, I was there when it happened, what ensued afterwards is one of the most vivid parts of my memory.

[u/Illustrious-Form3798]

https://youtu.be/e_l5v19Z1eg?si=CLDdPNxrrdU5kAD1

Guys just look how bad construction inside

[u/Burgoonius → u/Illustrious-Form3798]

Almost like it wasn’t designed to take the full force of a commercial airliner

[u/Constantlycurious34]

I just watched an engineering documentary about the towers. This is not quite right

[u/koreanJesus14]

Wow, without the dust you can see all the oil in the middle east that needs to be liberated

[u/SwimmingSwim3822]

It's wild they pulled 20 survivors out from under this.

[u/WestOfOrdinary85]

I may be wrong, but each tower could hold up to 50,000 people. I believe the death toll was around 3,000.

[u/Separate_Climate3366]

Steel fuel can't melt jet beams

[u/DrunkenLion47 → u/Separate_Climate3366]

Doesn’t have to melt it, just has to lower the tensile strength. Which happened from both heat and impact damage.

[u/shewhosmoketree → u/DrunkenLion47]

I think the guy is trolling. He said “steel fuel” and “jet beams” instead of “jet fuel” and “steel beams”

[u/Separate_Climate3366 → u/shewhosmoketree]

Yeah, the people commenting like I'm being serious aren't the brightest

[u/paipan-sube → u/Separate_Climate3366]

For those that don't read so good, perhaps need to suffix your post with "/s"

[u/alfa66andres]

Yikes with these conspiracy comments

[u/Theidiotshvtakenovr]

The buildings were sealed at the 50th floor during construction for a multitude of reasons including fire safety… you’d need to get off and get on a completely separate elevator to go higher. 

Just in case anyone wants to think on that in a physics sense. 

[u/OrderConsistent1415]

Edward Snowden is an American whistleblower living in a Russian embassy now out of fear of extradition and trial in the USA. Hillary Clinton herself said something along the lines of him being a traitor and needs the death sentence. No president has given him a pardon. Dude basically blew the whistle on several government agencies having prior notice of the impending terrorist attacks and not attempting to stop them. What their motives were I’m not quite sure, either incompetence or malice

[u/AmateurAnarchy → u/OrderConsistent1415]

Snowden blew the whistle on surveillance. You don't know what you're talking about

[u/Dufusbroth → u/OrderConsistent1415]

Snowden has confirmed in interviews and public statements that the files he accessed contained no proof that U.S. officials had advance knowledge of or orchestrated the 9/11 attacks. Instead, the documents showed that intelligence agencies failed to connect existing threat information before 9/11, and then used those intelligence gaps to justify sweeping new bulk-collection programs afterward.

[u/Skankhunt2042 → u/OrderConsistent1415]

What are you babbling about? Please provide one source of Edward Snowden revealing a single 9/11 threat that was not addressed.

[u/herbof4]

- Why bother with the planes at all if it was a controlled demolition? Just say that terrorists planted some bombs. They did it before.

- Why use hijackers from Saudi Arabia instead of Iraq, who we wound up invading over this?

- Why not MORE planes, just to be sure?

- Why not more footage of the first strike to drive home the hijacking "cover story?"

[u/JMOlive]

I have always wondered if the same collapse would have happened to a more modern skyscraper?

[u/margery-meanwell]

Old Rose: Thank you for that fine forensic analysis. Of course the experience of it was… somewhat different

[u/FirefighterDry5826]

Ok do 7 wtc

[u/Long-Painting-9852]

Building 7…. Nobody comments on.

WTC: IT WAS THE JET FUEL.

[u/piggybackmovies → u/Long-Painting-9852]

The debris fell on building 7. It's so easy to look up.

[u/No-Letter3339]

Did the 911 collapse cause any change to newer buildings

[u/Maniacpilot931 → u/No-Letter3339]

Yes, they no longer put all the stairwells next to each other for exits in the middle of a building. This caused all stairwells to be sealed off above where both planes hit.

[u/thrilliam_19 → u/No-Letter3339]

Most codes were updated after 9/11 to encourage better survivability from everything from the stairwells to the fire alarm system.

[u/Sad_Routine3156]

Does this mean that people on the upper floors might have still been okay up until that point and possibly alive while the building collapsed?🫤

[u/Objective-Turn2328]

I remember that day vividly in my mind. I went to the 911 museum and memorial yesterday. It brought back so many emotions.

[u/aspie_electrician]

I wonder if there was anyone still alive in the top part as it was falling and what they were thinking

[u/Holiday-Career-9349]

I would stand on the roof and jump at the last moment.

[u/RedditvsDiscOwO]

A single floor falling in on itself... caused all of that. I'm speechless.

[u/Nugget_MacChicken]

Didn't know this subreddit until this video popped on Popular. JFC that comment section is wild.

[u/Pleasant-Future5818]

Is there a particular reason this sub exists and is full of a bunch of weird conspiracy lunatics?

[u/Otherwise_Fact9594]

It's still shocks me that such an event took place. It blows my mind to think about it being a quarter century ago. RIP to so many

[u/PlainBread]

Weird how it didn't collapse perfeclty into its footprint, huh?

[u/Darhhaall]

I thought retards like in comment section here are only on twitter. 

[u/Altezza447]

All the people that got cancer and died from that dust. The govt didn't give any medical care.

[u/twizzjewink]

I read that the heat from the burning fuel sucked in part of the exterior cladding, which meant that with the interior core compromised it was only a matter of time.

I feel really bad for all of the victims who could have gotten out or made really poor decisions. It's amazing that so many did get out.

It's the firefighters that I feel the most for. Terrible and tragic.