# Skyscrapers on fire, not collapsing **URL:** \ **Category:** Great Debates\ **Created:** [September 12, 2010, 10:53pm UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541 "2010-09-12T22:53:57Z")\ **Posts on this page:** 20\ **Page:** 18
**Author:** ![Cisco](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Cisco](https://boards.straightdope.com/u/Cisco)\ **Post date:** [September 24, 2010, 11:27pm UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/342 "2010-09-24T23:27:52Z")
> [@Mozart1220](#): > > I think I mentioned the odds of even one skyscraper falling straight down into it’s own foorprint. We had THREE, and one wasn’t even hit by a plane. What are those odds, and how did you calculate them? > [@Mozart1220](#): > > I think the “official” explaination for building 7 was “overwheight air conditioning units on the roof” > > Please… Where did you see this explanation? Will you abandon this idea if we can show you that it is not, in fact, the “official” explanation? Also, now that post #153 has been clearly explained to you at least 6 or 8 times, including a link to a concise Wikipedia article, will you actually respond to it? And how 'bout post #302-- any interest at all in responding to that? ---
**Author:** ![Valgard](https://avatars.discourse-cdn.com/v4/letter/v/7feea3/32.png) [@Valgard](https://boards.straightdope.com/u/Valgard)\ **Post date:** [September 24, 2010, 11:28pm UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/343 "2010-09-24T23:28:51Z")
> [@Mozart1220](#): > > I think I mentioned the odds of even one skyscraper falling straight down into it’s own foorprint. We had THREE, and one wasn’t even hit by a plane. You did and I responded to that back in post #255. Structures like that will not tip over like a signpost. This gets into some basic structural engineering and physics but skyscrapers aren’t designed to carry loads that way even without having major portions of the structural system knocked out. When I look at those buildings collapsing it looks pretty much like what I’d expect. I’m still trying to understand **why** you think it’s impossible or unlikely for those buildings to fall down as they did, given the damage that they suffered. I’m assuming that you don’t have any kind of background in structural engineering or some related field (since that question has been asked several times and not answered), so what’s your basis for that statement? Does it just “look wrong” or is there something in particular that stands out? > [@Mozart1220](#): > > I think the “official” explaination for building 7 was “overwheight air conditioning units on the roof” > > Please… No, that is incorrect. Here’s a link to the NIST website with tons of links to their analysis, questions about their analysis and so on, in nauseating detail. > **[World Trade Center Investigation](https://www.nist.gov/world-trade-center-investigation)** > > The collapse of the WTC buildings following the terrorist attacks on September 11, 2001, was one of the worst buildin Roughly speaking, WTC7 had some very long columns which lost their lateral support when various steel members expanded from the heat of the fires in that building. Poorly braced long columns collapse much more easily which led to the building coming down. As far as WTC1 & 2, here’s a grossly simplified example of how a structure can collapse straight down when a small, but critical, flaw is introduced. Take an empty soda can and stand on it. It’ll hold your weight. Now have someone tap the side with their toe - it doesn’t have to be much, a pretty small dent in the cylinder wall leads to what is called “local buckling” and the structure (the can) suffers a dramatic loss of strength. The can is immediately crushed flat by the dead load (your weight). ---
**Author:** ![psikeyhackr](https://avatars.discourse-cdn.com/v4/letter/p/97f17d/32.png) [@psikeyhackr](https://boards.straightdope.com/u/psikeyhackr)\ **Post date:** [September 24, 2010, 11:47pm UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/344 "2010-09-24T23:47:38Z")
> [@Valgard](#): > > It may not seem obvious or believable to many people, and that’s not because they are stupid, it’s because most people do not have an education or work experience in a related field and also because our everyday experience with things breaking, falling down and so on is limited to small stuff - a tree falls over, my bookshelf tips, that kind of thing. Those events don’t just scale up linearly to massive structures. The behavior changes dramatically as the size of the objects involved changes. > > Do you have some particular reason for saying that it’s not believable, or does it just not “seem right”?. That is why I use paper supports to scale the strength down to the mass I am using. [![](https://i.ytimg.com/vi/caATBZEKL4c/hqdefault.jpg?sqp=-oaymwEmCOADEOgC8quKqQMa8AEB-AHeAoAC8AGKAgwIABABGGUgVihLMA8=&rs=AOn4CLD2Q6U_x6g4lAMHx50P-v7cDaPRdg "Gravitational Collapse onto Cumulative Supports") ](https://www.youtube.com/watch?v=caATBZEKL4c) But of course then geniuses say the WTC was not made of paper. psik ---
**Author:** ![begbert2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/begbert2/32/3357_2.png) [@begbert2](https://boards.straightdope.com/u/begbert2)\ **Post date:** [September 24, 2010, 11:53pm UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/345 "2010-09-24T23:53:03Z")
> [@psikeyhackr](#): > > > [@Valgard](#): > > > > It may not seem obvious or believable to many people, and that’s not because they are stupid, it’s because most people do not have an education or work experience in a related field and also because our everyday experience with things breaking, falling down and so on is limited to small stuff - a tree falls over, my bookshelf tips, that kind of thing. Those events don’t just scale up linearly to massive structures. The behavior changes dramatically as the size of the objects involved changes. > > > > Do you have some particular reason for saying that it’s not believable, or does it just not “seem right”?. > > That is why I use paper supports to scale the strength down to the mass I am using. > > [http://www.youtube.com/watch?v=caATBZEKL4c](http://www.youtube.com/watch?v=caATBZEKL4c) > > But of course then geniuses say the WTC was not made of paper. > > psik Of course it wasn’t made of paper. It was made of SOLID RINGS OF SOLID ADAMANTIUM. It sure as hell wasn’t made of a lattice of steel girders that in scale with your model would be about as thick as a hair. ---
**Author:** ![Mozart1220](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@Mozart1220](https://boards.straightdope.com/u/Mozart1220)\ **Post date:** [September 25, 2010, 12:08am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/346 "2010-09-25T00:08:44Z")
> [@Valgard](#): > > > [@Mozart1220](#): > > > > I think I mentioned the odds of even one skyscraper falling straight down into it’s own foorprint. We had THREE, and one wasn’t even hit by a plane. > > You did and I responded to that back in post #255. Structures like that will not tip over like a signpost. This gets into some basic structural engineering and physics but skyscrapers aren’t designed to carry loads that way even without having major portions of the structural system knocked out. When I look at those buildings collapsing it looks pretty much like what I’d expect. > > I’m still trying to understand **why** you think it’s impossible or unlikely for those buildings to fall down as they did, given the damage that they suffered. I’m assuming that you don’t have any kind of background in structural engineering or some related field (since that question has been asked several times and not answered), so what’s your basis for that statement? Does it just “look wrong” or is there something in particular that stands out? > > > [@Mozart1220](#): > > > > I think the “official” explaination for building 7 was “overwheight air conditioning units on the roof” > > > > Please… > > No, that is incorrect. Here’s a link to the NIST website with tons of links to their analysis, questions about their analysis and so on, in nauseating detail. > > [http://wtc.nist.gov/](http://wtc.nist.gov/) > > Roughly speaking, WTC7 had some very long columns which lost their lateral support when various steel members expanded from the heat of the fires in that building. Poorly braced long columns collapse much more easily which led to the building coming down. > > As far as WTC1 & 2, here’s a grossly simplified example of how a structure can collapse straight down when a small, but critical, flaw is introduced. > > Take an empty soda can and stand on it. It’ll hold your weight. Now have someone tap the side with their toe - it doesn’t have to be much, a pretty small dent in the cylinder wall leads to what is called “local buckling” and the structure (the can) suffers a dramatic loss of strength. The can is immediately crushed flat by the dead load (your weight). Providing my wieght is exactly balanced on the can, and providing the can is not weaker in some way on one side or the other, by say, a fire on one side and not the other. And again, how many steel building have collpased due to fire? I think THREE now, in all of history. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [September 25, 2010, 12:15am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/347 "2010-09-25T00:15:03Z")
> [@Mozart1220](#): > > I think I mentioned the odds of even one skyscraper falling straight down into it’s own foorprint. Please post examples of the vast majority of fallen skyscrapers that did not collapse predominantly straight down. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [September 25, 2010, 12:18am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/348 "2010-09-25T00:18:12Z")
> [@Mozart1220](#): > > And again, how many steel building have collpased due to fire? I think THREE now, in all of history. Which is 100% of all steel frame skyscrapers that have ever collapsed. If you have exceptions, post 'em. ---
**Author:** ![Mozart1220](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@Mozart1220](https://boards.straightdope.com/u/Mozart1220)\ **Post date:** [September 25, 2010, 1:24am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/349 "2010-09-25T01:24:02Z")
> [@Fear\_Itself](#): > > > [@Mozart1220](#): > > > > I think I mentioned the odds of even one skyscraper falling straight down into it’s own foorprint. > > Please post examples of the vast majority of fallen skyscrapers that did not collapse predominantly straight down. Which brings us to the number of skyscrapers that have collpased for any reason other than Earthquake, which I think we can all agree is another level of destruction altogether. I’d bet that number is very close to zero, which is the number of skyscrapers previous to these which have collapsed due to fire. Wouldn’t it just be easier to admit that this a completely unique occurance, and that you are looking very hard for excuses why there WOULDN’T have to be preset explosives? ---
**Author:** ![Mozart1220](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@Mozart1220](https://boards.straightdope.com/u/Mozart1220)\ **Post date:** [September 25, 2010, 1:26am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/350 "2010-09-25T01:26:38Z")
> [@Fear\_Itself](#): > > > [@Mozart1220](#): > > > > And again, how many steel building have collpased due to fire? I think THREE now, in all of history. > > Which is 100% of all steel frame skyscrapers that have ever collapsed. If you have exceptions, post 'em. THat’s kinda what I’m saying here. Steel buildings DO NOT collpase due to fire. The fire inviolved was not nearly hot enough to melt the girders. And the straight down thing was pretty strange. You woyuld have thought that just the floors above the damaged area would ahve “sloughed off”. In fact on one tower you can actually see this happening and then STRAIGHTEN IT’S SELF OUT. (Watch the antenna) Pretty odd, going against gravity like that. ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [September 25, 2010, 1:27am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/351 "2010-09-25T01:27:56Z")
> [@Mozart1220](#): > > > [@Fear\_Itself](#): > > > > Please post examples of the vast majority of fallen skyscrapers that did not collapse predominantly straight down. > > Which brings us to the number of skyscrapers that have collpased for any reason other than Earthquake, which I think we can all agree is another level of destruction altogether. > > I’d bet that number is very close to zero, which is the number of skyscrapers previous to these which have collapsed due to fire. > Wouldn’t it just be easier to admit that this a completely unique occurance, and that you are looking very hard for excuses why there WOULDN’T have to be preset explosives? Well, yes, this was a unique occurance, as very few other large buildings have had airliners full of fuel deliberately flown into them. Why do you feel there is a need for explosives (which would make these just like controlled demolitions of buildings which did not have planes flown into them)? ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [September 25, 2010, 1:29am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/352 "2010-09-25T01:29:36Z")
> [@Mozart1220](#): > > > [@Fear\_Itself](#): > > > > Which is 100% of all steel frame skyscrapers that have ever collapsed. If you have exceptions, post 'em. > > THat’s kinda what I’m saying here. Steel buildings DO NOT collpase due to fire. That is significant only if you can show comparable skyscraper fires that did not collapse. Otherwise, meh. > [@](#): > > The fire inviolved was not nearly hot enough to melt the girders. Irrelevant. They don’t need to melt, just get hot enough to weaken the steel. Gravity does the rest. > [@](#): > > And the straight down thing was pretty strange. No, falling like a tree would be strange. Straight down is fully consistent with gravity. ---
**Author:** ![Mozart1220](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@Mozart1220](https://boards.straightdope.com/u/Mozart1220)\ **Post date:** [September 25, 2010, 1:36am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/353 "2010-09-25T01:36:56Z")
> [@Fear\_Itself](#): > > > [@Mozart1220](#): > > > > THat’s kinda what I’m saying here. Steel buildings DO NOT collpase due to fire. > > That is significant only if you can show comparable skyscraper fires that did not collapse. Otherwise, meh. > Irrelevant. They don’t need to melt, just get hot enough to weaken the steel. Gravity does the rest. > > \*\*\*Not enough heat for that either. \*\*\* > > > [@](#): > > > > And the straight down thing was pretty strange. > > No, falling like a tree would be strange. Straight down is fully consistent with gravity. _ **Not when the top is already sliding off to the side…** _ ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [September 25, 2010, 1:45am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/354 "2010-09-25T01:45:28Z")
> [@Mozart1220](#): > > \*\*\*Not enough heat for that either. \*\*\* Yes there was. * * * > [@](#): > > Not when the top is already sliding off to the side… \*\*\*The top of the tower never tilted outside of the footprint. ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [September 25, 2010, 1:54am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/355 "2010-09-25T01:54:00Z")
> [@Mozart1220](#): > > _ **Not when the top is already sliding off to the side…** _ Not sliding off to the side, although the way that one side collapsed before the other might make it look as if it was “sliding.” ---
**Author:** ![JXJohns](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jxjohns/32/469_2.png) [@JXJohns](https://boards.straightdope.com/u/JXJohns)\ **Post date:** [September 25, 2010, 2:27am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/356 "2010-09-25T02:27:10Z")
> [@Mozart1220](#): > > …The fire inviolved was not nearly hot enough to melt the girders. It didn’t need to melt, just soften a bit. Jesus, go read a book or something. ---
**Author:** ![psikeyhackr](https://avatars.discourse-cdn.com/v4/letter/p/97f17d/32.png) [@psikeyhackr](https://boards.straightdope.com/u/psikeyhackr)\ **Post date:** [September 25, 2010, 2:47am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/357 "2010-09-25T02:47:54Z")
> [@Valgard](#): > > I’m still trying to understand **why** you think it’s impossible or unlikely for those buildings to fall down as they did, given the damage that they suffered. I’m assuming that you don’t have any kind of background in structural engineering or some related field (since that question has been asked several times and not answered), so what’s your basis for that statement? Does it just “look wrong” or is there something in particular that stands out? The problem is the collapse TIME. Dr. Sunder of the NIST says it was 11 seconds of the north tower. > **[NOVA | Building on Ground Zero | 9/11 Conspiracy Theories | PBS](https://www.pbs.org/wgbh/nova/wtc/cons-flash.html)** > > (Flash) Dr. S. Shyam Sunder of NIST discusses 9/11 conspiracy theories. If the towers accelerated downwards at 50% of gravitational acceleration it would take 18 seconds. A magical collapse assuming masses floating in space with no supports would take 12 seconds simply due to the conservation of momentum. Her is a Python program for it: > **[The 9/11 Forum-Crush-down models](https://www.tapatalk.com/groups/the911forum/crush-down-models-t145-s300.html#p10572)** > > When it comes to notions like psychic spoon bending, I point to the lack of experimental confirmation, just as I do for the official stories for how t So how does that core not make it take longer than 18 seconds? In fact, why didn’t the core cause the top of the south tower to fall down the side? psik ---
**Author:** ![Mr.Miskatonic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.miskatonic/32/310_2.png) [@Mr.Miskatonic](https://boards.straightdope.com/u/Mr.Miskatonic)\ **Post date:** [September 25, 2010, 3:00am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/358 "2010-09-25T03:00:50Z")
> [@Mozart1220](#): > > \*\*\*Not enough heat for that either. \*\*\* You are certain of this how? BTW, you are wrong. > [@](#): > > _ **Not when the top is already sliding off to the side…** _ The top block tilted. It did not slide. Then it acted like any lever that crushes its fulcrum. Even if it were like you say: just what magical explosives or thermite could make what you saw happen? This is like the idiotic Jones claim that the block was dissolved with explosive without knowing a bit about how much explosives that would take. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [September 25, 2010, 3:04am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/359 "2010-09-25T03:04:09Z")
[QUOTE=psikeyhackr] The problem is the collapse TIME. [/QUOTE] Serious question here…assuming you are 100% correct (you aren’t of course, but for shits and giggles assume you are), do you really think no one else can do math? Have all the experts in the various fields really never heard of a calculator? And if not, how do you explain the glaring fact that the vast majority haven’t twigged to this supposed discrepancy? Are they all in on it? Do none of them have access to a calculator? None of them ever taken first year physics? Never heard of that Newton guy? How do you explain this? I’m genuinely puzzled why people believe this stuff, so help me out here and fight my ignorance of da crazy by explaining to me how all the experts could miss this seemingly glaring issue. After you explain it I’ll be happy to link to sites debunking this (assuming that other 'dopers don’t beat me to it), but I’d really like you to answer the question if you would. -XT ---
**Author:** ![sparky\_1](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@sparky\_1](https://boards.straightdope.com/u/sparky_1)\ **Post date:** [September 25, 2010, 3:09am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/360 "2010-09-25T03:09:40Z")
psik: I took the time in the other thread to explain pretty well exactly why your way of thinking and your arguments are totally wrong, yet you seemed never to read it or comment. You are not, and never will be looking for answers. People repeatedly take the time to explain and educate you, yet you continue to ignore them. Personally, I find it rude and insulting and damaging to any meaningful debate. ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [September 25, 2010, 3:19am UTC](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541/361 "2010-09-25T03:19:06Z")
> [@psikeyhackr](#): > > > [@Valgard](#): > > > > I’m still trying to understand **why** you think it’s impossible or unlikely for those buildings to fall down as they did, given the damage that they suffered. I’m assuming that you don’t have any kind of background in structural engineering or some related field (since that question has been asked several times and not answered), so what’s your basis for that statement? Does it just “look wrong” or is there something in particular that stands out? > > The problem is the collapse TIME. > > Dr. Sunder of the NIST says it was 11 seconds of the north tower. > > [NOVA | Building on Ground Zero | 9/11 Conspiracy Theories | PBS](http://www.pbs.org/wgbh/nova/wtc/cons-flash.html) > > If the towers accelerated downwards at 50% of gravitational acceleration it would take 18 seconds. A magical collapse assuming masses floating in space with no supports would take 12 seconds simply due to the conservation of momentum. > > Her is a Python program for it: > > [Crush-down models - Page 21 - The 9/11 Forum](http://the911forum.freeforums.org/post10572.html#p10572) > > So how does that core not make it take longer than 18 seconds? In fact, why didn’t the core cause the top of the south tower to fall down the side? > > psik How many questions do you have? Is there a limit to these ghodforsaken questions, or is it your intention to keep recycling these inane questions over and over and over and over and over and over and over and over and over and over again? You and your Truther compatriots haven’t come up with a new question in years, and all of your old ones have been answered…and ignored. I think a moratorium should be called on any more answers until you and your deliberately ignorant compatriots acknowledge the facts that have repeatedly been provided you. [Previous page](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541.md?page=17) [Next page](https://boards.straightdope.com/t/skyscrapers-on-fire-not-collapsing/553541.md?page=19)