# If the planes that crashed into the WTC had no fuel, would the buildings survive? **URL:** \ **Category:** Factual Questions\ **Created:** [September 6, 2011, 6:41am UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365 "2011-09-06T06:41:54Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Darth\_Ayebaw](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darth_ayebaw/32/9870_2.png) [@Darth\_Ayebaw](https://boards.straightdope.com/u/Darth_Ayebaw)\ **Post date:** [September 6, 2011, 6:41am UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/1 "2011-09-06T06:41:54Z")
It was the fire that caused the structural failure, right? I mean the planes blew away most everything that was meant to withstand the fire, and eventually it grew hot enough to weaken the steel and bring down the buildings. But say the planes had no fuel left to start or fuel fires… say it was running on fumes and ran out completely just as the planes impacted. Would the buildings still be standing? I mean it took them a while to come down as is, fire was the main problem, and it’s been said about the buildings themselves that even if a commercial airliner crashed into them it wouldn’t knock them down. Second question: if they did survive the impacts due to lack of fire, or smaller planes or whatever scenario you want to make up, what would’ve been done with the buildings? Could they have been repaired? How would all the debris be removed? ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [September 6, 2011, 7:12am UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/2 "2011-09-06T07:12:38Z")
WAG, but I think it is reasonable to say that neither tower would have fallen if the jet fuel had not comprimised the steel framework. With that said I don’t see any way possible to repair the kind of damage that was done to the buildings. Of course I am not a engineer, so maybe I am wrong. But I would think that after sustaining that kind of damge the only option would be to demolish the tower. That in itself would seem to present an almost insurmountable problem. Yes, I am aware that buildings can be imploded on themselves. However, given the close proximity of the trade centers to other buildings I would think that it would be a huge techincal problem. Also, what challenges would be presented in trying to bring the building down with the damge present. Could it be made to fall onto itself with the damage? Or would the damage cause it to lean as it was falling? Of course we all know that the buildings came down pretty much in a pancake pattern. But would the same hold true if they were brought down by conventional means? Has there been a building anywhere near the size of one of the towers that has been demolished? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 6, 2011, 7:21am UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/3 "2011-09-06T07:21:20Z")
> [@obbn](#): > > WAG, but I think it is reasonable to say that neither tower would have fallen if the jet fuel had not comprimised the steel framework. With that said I don’t see any way possible to repair the kind of damage that was done to the buildings. Of course I am not a engineer, so maybe I am wrong. But I would think that after sustaining that kind of damge the only option would be to demolish the tower. > > That in itself would seem to present an almost insurmountable problem. Yes, I am aware that buildings can be imploded on themselves. However, given the close proximity of the trade centers to other buildings I would think that it would be a huge techincal problem. Also, what challenges would be presented in trying to bring the building down with the damge present. Could it be made to fall onto itself with the damage? Or would the damage cause it to lean as it was falling? > > Of course we all know that the buildings came down pretty much in a pancake pattern. But would the same hold true if they were brought down by conventional means? Has there been a building anywhere near the size of one of the towers that has been demolished? Largely I agree. Some nitpicks though… While the towers mostly collapsed straight down substantial amounts of crap went further afield. They did not cleanly fall in on themselves but rather caused damage in a radius around them. I agree the damage was substantial and had they not collapsed not sure what they would have done. My guess is they’d start dismantling the towers from the top down to the damage. Then rebuild the tower back up. The only other alternative would be to dismantle them entirely from the top down. It is an interesting question to wonder what they would do in that case. I am guessing there is no solid answer. It’d be after an assessment of the damage and the costs involved. Since the towers collapsed no assessment was made about repairing the towers. ---
**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 6, 2011, 8:03am UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/4 "2011-09-06T08:03:43Z")
I’ve wondered about this. Basically, I would imagine that temporary bracing would need to be brought in, just to ensure structural integrity. Then once in place, an analysis could be done to determine to keep the structures (if possible) or to demo them (and determining the huge issue that would be). So, either way there would be a rush to secure the structure, with crews doing very dangerous work as quickly as possible. But man, how would you even get the temporary steel in place? I would imagine elevator shafts could be used, with elevators replaced with hoists and such (like hydraulic strand jacks). Then just a question of getting the temporary steel in place and the damaged members removed. That all assumes any safe work could occur at all. ---
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [September 6, 2011, 12:20pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/5 "2011-09-06T12:20:45Z")
> [@Whack-a-Mole](#): > > I agree the damage was substantial and had they not collapsed not sure what they would have done. My guess is they’d start dismantling the towers from the top down to the damage. Then rebuild the tower back up. > > The only other alternative would be to dismantle them entirely from the top down. > > It is an interesting question to wonder what they would do in that case. I am guessing there is no solid answer. It’d be after an assessment of the damage and the costs involved. Since the towers collapsed no assessment was made about repairing the towers. The scenario where the towers remain standing but unoccupied reminds me of the case of [One Meridian Plaza](http://en.wikipedia.org/wiki/One_Meridian_Plaza#After_the_fire), which suffered a major fire affecting five floors in 1991. The tower sat damaged (but stable) and unoccupied for six years, driving down property values in the area, while the insurers wrangled over how and whether it could safely be rebuilt. The city of Philadelphia ended up suing the building’s owners to get them to either demolish or rebuild, and in the end the owners choose to demolish. The WTC towers were owned by a govermental-type organization, of course, so it’s possible that some wrangling could have been avoided in that hypothetical. But if the towers had remained standing, my gut feeling is that a similar scenario would have played out in New York, with two vacant and visibly scarred towers looming over the skyline for several years after the attack. ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [September 6, 2011, 12:39pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/6 "2011-09-06T12:39:30Z")
The biggest problem would have been the structure of the building. The WTC was a different type of design than other buildings: the load-bearing walls were on the outside. The planes would have wrecked the structural integrity of the building, fire or not. The remaining walls would be badly stressed and there would be imminent danger of them failing and the towers collapsing. It would give more time to rescue people, but the only way to save the building would have been to shore up the outside walls, something that was risky, to say the least, and not certain to help. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [September 6, 2011, 2:06pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/7 "2011-09-06T14:06:52Z")
Is it possible that the damage would be confined enough to the collision area that the buildings could be torn down to a certain level but remain in use, just shorter than their original design? I realize you’d have to rejigger the elevator sytem. The Empire State Building was once struck by a plane and survived: [1945 Empire State Building B-25 crash - Wikipedia](http://en.wikipedia.org/wiki/B-25_Empire_State_Building_crash) Speaking of the ESB, here’s an interesting what-if book about tearing it down: [http://www.amazon.com/Unbuilding-Sandpiper-David-Macaulay/dp/0395454255/ref=sr\_1\_1?s=books&ie=UTF8&qid=1315317932&sr=1-1](http://www.amazon.com/Unbuilding-Sandpiper-David-Macaulay/dp/0395454255/ref=sr_1_1?s=books&ie=UTF8&qid=1315317932&sr=1-1) ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [September 6, 2011, 4:39pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/8 "2011-09-06T16:39:15Z")
The crash did not weaken the structure. The crash and fire took out the fire main suports causing them to drop and then the heat from the fire weaked the structure. And I believe the strenght fo the structure is the core of the building. The walls on a steal building give stabilty, that is help stop sway. And beams and bracing can be added to the inside of the floor. Worse case would be some loss of rentable space. I know of a 3 story building that the columns were shattered where the 2 and 3rd floors dropped about 12 inches. They braced the floors with tembers. Then jacked each floor up to the proper level. cut out the old columns, put in new columns, cleaned up and reopened building. ---
**Author:** ![AndrewL](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AndrewL](https://boards.straightdope.com/u/AndrewL)\ **Post date:** [September 6, 2011, 4:50pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/9 "2011-09-06T16:50:52Z")
Most of the fuel which fed the fires was already in the building, in the form of normal office contents. Modern office buildings already contain a remarkably large amount of combustible material - paper, plastics, wood furniture, flammable insulation, PVC pipe, etc. The fuel from the crashed planes mostly acted as an accelerant to set multiple entire floors on fire at once. Had the planes been somehow empty of fuel, it’s likely that there would have been fires anyway, simply from the heat of impact and severed electrical wiring, but it would have started and spread more slowly. With the building’s own fire suppression systems not working, would firefighters have been able to fight that fire and put it out before it spread far enough to trigger a collapse? I don’t know. ---
**Author:** ![postcards](https://avatars.discourse-cdn.com/v4/letter/p/8e8cbc/32.png) [@postcards](https://boards.straightdope.com/u/postcards)\ **Post date:** [September 6, 2011, 6:04pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/10 "2011-09-06T18:04:11Z")
> [@Snnipe\_70E](#): > > The crash did not weaken the structure. The crash and fire took out the fire main suports causing them to drop and then the heat from the fire weaked the structure. And I believe the strenght fo the structure is the core of the building. The walls on a steal building give stabilty, that is help stop sway. Just about all of this is incorrect; see **RealityChuck** ’s comments two posts above yours. ---
**Author:** ![anson2995](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@anson2995](https://boards.straightdope.com/u/anson2995)\ **Post date:** [September 6, 2011, 6:05pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/11 "2011-09-06T18:05:34Z")
> [@obbn](#): > > Of course we all know that the buildings came down pretty much in a pancake pattern. But would the same hold true if they were brought down by conventional means? Has there been a building anywhere near the size of one of the towers that has been demolished? No. The largest buildings to be imploded are in the 30-story range. I imagine that a controlled implosion would have been difficult given the proximity of other buildings in the complex. But buildings taller than 30 stories have been deconstructed. The Singer Building (which was once the tallest building in the world, and coincidentally stood across the street from the WTC site) was torn down in 1968. The Deutsche Bank Building was about 50 stories IIRC, and they just finished tearing it down earlier this year. It was heavily damaged by the collapse of the WTC’s south tower. I’m sure there are other examples. Some of the buildings around the WTC were damaged from the buildings’ collapses, but it’s worth noting that there was also significant damage from the initial explosions. Engines and landing gear landed 1500 feet away, as did pieces of the building. ---
**Author:** ![isaiahrobinson](https://avatars.discourse-cdn.com/v4/letter/i/85e7bf/32.png) [@isaiahrobinson](https://boards.straightdope.com/u/isaiahrobinson)\ **Post date:** [September 6, 2011, 7:11pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/12 "2011-09-06T19:11:17Z")
> [@AndrewL](#): > > Most of the fuel which fed the fires was already in the building, in the form of normal office contents. Modern office buildings already contain a remarkably large amount of combustible material - paper, plastics, wood furniture, flammable insulation, PVC pipe, etc. The fuel from the crashed planes mostly acted as an accelerant to set multiple entire floors on fire at once. Had the planes been somehow empty of fuel, it’s likely that there would have been fires anyway, simply from the heat of impact and severed electrical wiring, but it would have started and spread more slowly. With the building’s own fire suppression systems not working, would firefighters have been able to fight that fire and put it out before it spread far enough to trigger a collapse? I don’t know. This was basically what I had figured: the jet fuel multiplied the problem but when you have tonnes of steel slamming into each other at hundreds of miles an hour, that’s always going to create sparks and enormous temperatures. Throw in all the electricity and the fact that most constituent parts of a building are probably combustible at those temperatures and my guess would be that severe fires were unavoidable either way. But that’s just my intuition. ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [September 6, 2011, 7:46pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/13 "2011-09-06T19:46:56Z")
> [@Darth\_Ayebaw](#): > > If the planes that crashed into the WTC had no fuel, would the buildings survive? Well, on second thought no, no they wouldn’t have survived. Everyone knows that regardless of the damage that the planes did the building was brought down by expolsives placed in the building by the Bush administration. Geez, are you people sheep? /Sorry, had to get a little snarky today and open up a can of worms. //put your tin foil hats on now boys, they are going to be coming out of the woodwork ///never knew trolling could be so much fun!😃 ---
**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 6, 2011, 7:49pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/14 "2011-09-06T19:49:26Z")
> [@obbn](#): > > Well, on second thought no, no they wouldn’t have survived. Everyone knows that regardless of the damage that the planes did the building was brought down by expolsives placed in the building by the Bush administration. Geez, are you people sheep? > > /Sorry, had to get a little snarky today and open up a can of worms. > //put your tin foil hats on now boys, they are going to be coming out of the woodwork > ///never knew trolling could be so much fun!😃 Careful. We purge truthers with fire around here. ---
**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 6, 2011, 7:51pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/15 "2011-09-06T19:51:19Z")
> [@Elendil\_s\_Heir](#): > > Is it possible that the damage would be confined enough to the collision area that the buildings could be torn down to a certain level but remain in use, just shorter than their original design? I realize you’d have to rejigger the elevator sytem. > > The Empire State Building was once struck by a plane and survived: [1945 Empire State Building B-25 crash - Wikipedia](http://en.wikipedia.org/wiki/B-25_Empire_State_Building_crash) Very different cases. The ESB had a different construction method and the plane that hit it was much, much smaller and going much slower. ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [September 6, 2011, 8:00pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/16 "2011-09-06T20:00:51Z")
> [@Mr.Miskatonic](#): > > Careful. We purge truthers with fire around here. And pitchforks? I was hoping there would be pitchforks. Seriously though, I am not a Truther, although I am very surprised one hasn’t shown up in this thread yet. Good job SD in keeping away the nuts. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [September 6, 2011, 8:01pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/17 "2011-09-06T20:01:58Z")
If you want some bedtime reading, have a look at the [NIST reports](http://www.nist.gov/el/disasterstudies/wtc/wtc_finalreports.cfm) into the collapse. > [@](#): > > [In WTC2]As in WTC1, less than 15 percent of the jet fuel burned in the spray cloud inside the building. Roughly 10 percent to 25 percent was consumed in the fireballs outside the building. Thus, well over half of the jet fuel remained after the initial fireballs That unburned fuel later fed the extremely intense fires that led to the collapse - without it they would not have been as severe. Also, don’t underestimate the effect of those initial fireballs in weakening the structure: > [@](#): > > The rapid burning of the jet fuel inside the building created an overpressure that was estimated at 2 psi to 3 psi for 0.5 s to 2 s. […] It is not unreasonable that a combination of physical damage from the impact and overpressure from the fireballs caused the partial collapse of [some] floor slabs (from p42 of the final report) ---
**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 6, 2011, 8:14pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/18 "2011-09-06T20:14:32Z")
Just a nitpick, but: [QUOTE=RealityChuck] The biggest problem would have been the structure of the building. The WTC was a different type of design than other buildings: the load-bearing walls were on the outside. The planes would have wrecked the structural integrity of the building, fire or not. [/QUOTE] The building core also was load bearing, and used floor trusses tied into the core and the outer skin (which was comprised of Vierendeel trusses all along the exterior and tied into the facade). I’ve heard it described as a ‘tube in a tube’ design. Both the outer tube and inner tube were load bearing though, and used to tie the floors together…that’s what gave the WTC buildings the unique (at the time) large open spaces on each floor…they didn’t have a bunch of vertical support beams throughout each floor. That said, the planes were flying fast enough that they definitely DID damage the core as well as cut through the exterior supports (and cut through multiple floors since both hit at an angle). I’m not sure if the building would have failed regardless, but I certainly think that the structural integrity was compromised, and that both buildings would have almost certainly have had to be taken down, or at least massively renovated and re-certified. -XT ---
**Author:** ![Darth\_Ayebaw](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darth_ayebaw/32/9870_2.png) [@Darth\_Ayebaw](https://boards.straightdope.com/u/Darth_Ayebaw)\ **Post date:** [September 6, 2011, 9:35pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/19 "2011-09-06T21:35:22Z")
Even if fires had started, would they burn hot enough to warp the steel without the fuel? Or if you get a big enough blaze, will you inevitable reach high enough temperatures? Suppose fire doesn’t exist is what I was asking at first. Let’s say the planes run out of fuel right before impact, and all fires are instantly put out. Was the structure damaged enough by the impact alone to collapse? ---
**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 6, 2011, 9:43pm UTC](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365/20 "2011-09-06T21:43:00Z")
[QUOTE=Darth Ayebaw] Even if fires had started, would they burn hot enough to warp the steel without the fuel? [/QUOTE] No, of course not. To melt steel you need temp above (IIRC) 1700 degrees. But you don’t NEED to melt the steel…just weaken it, to cause the beam to fail. Heating a structural steel beam in burning jet fuel is certainly enough to cause it to deform. Even a small deformation of a load bearing beam is going to start to cause the structure to fail, as we are talking about some serious load here. > [@](#): > > Or if you get a big enough blaze, will you inevitable reach high enough temperatures? No, to melt steel you need something like a blast furnace. But to soften steel you need a lot less heat. This is one of those things that Truthers never seem to be able to grasp or acknowledge…you don’t actually have to melt the steel beams to cause them to fail. > [@](#): > > Was the structure damaged enough by the impact alone to collapse? Obviously it wasn’t enough to cause the structure to fail immediately, or it would have. I don’t know if it would have eventually failed without the fire. It’s possible that it would have failed, but perhaps not as catastrophically. Then again, once you get that much mass moving downwards nothing is going to stop it. -XT [Next page](https://boards.straightdope.com/t/if-the-planes-that-crashed-into-the-wtc-had-no-fuel-would-the-buildings-survive/595365.md?page=2)