I'm stumped by a conspiracy theory.

[Glider]

I don't buy into conspiracy theories, but in a debate with a friend, I was stumped by a few points he made. He gave me some YouTube links to check out (yeah, I know), but I'm still stumped. Mainly because I'm not a physicist or a structural engineer I suspect.

 

Here are the points I could use some help with (I'm just trying to summarise his whole argument here):

 

1) Three buildings, despite suffering different structural damage (i.e. two being hit at different points and burning for different times, one not being hit at all apart from by debris from the othersl), all manage to fall tidily into their own footprint with almost no deflection or resistance from the more ridgid and undamaged sections below.

 

2) All manage to do so at speeds approaching freefall velocity, i.e. falling in around 10 seconds or so, where (he says) resistance from the undamaged sections (and their undamaged 47 central supporting columns) should have provided at least some resistance. Even if each floor had provided only a quarter of second resistance to the falling floors above, it should have taken over 24 seconds for them to fall. More realistically (he says) given the in-built redundancy of the central supports, it should have taken around 40 seconds (i.e. half a second resistance by each floor).

 

3) The controlled demolition hypothesis of Bulding 7. This (I'm told) only suffered external 'gouging' damage on one side and only burned on two floors, yet fell in the same manner as the towers (i.e. straight down into its own footprint and very quickly), and inconsistently with the damage it suffered. It apparently left a debris field radius of only 70 feet. The Oklahoma city bombing did much more catastrophic damage but a good part of the buiding remained standing.

 

4) Not strictly related, but odd. Apparently, the BBC released news of the Salmon brothers building collapse 20 minutes before it did. You can see the building in the background of the live report here.

 

As I say, I don't buy into conspiracy theories, so I don't want to start a debate on this, nor am I interested in theories concerning 'whodunnit' or why. It's only 'how' explanations I really need, and I'm sure there are people here who have enough physics and/or engineering knowledge to help me out in this debate (he thinks he's won). I would just tell him to bugger off, but he does so enjoy buying tequila

[insane_alien]

1) Three buildings, despite suffering different structural damage (i.e. two being hit at different points and burning for different times, one not being hit at all apart from by debris from the othersl), all manage to fall tidily into their own footprint with almost no deflection or resistance from the more ridgid and undamaged sections below.

 

well, the towers were actually designed to be able to do this from the way they were constructed (a central core and a shell) the core carried most of the weight and fell first. this had the effect of yanking the walls in. it should also be noted that the top of one of the towers hinged over as it fell. harldy neat and tidy.

 

also, if you do the stress calculations, it would have been impossible for the non damaged sectors to let the building fall over on its side as the support would buckle long before the centre of gravity got outside the footprint of the building.

 

as for WTC 7 it rotated significantly in its collapse and its collapse started at the bottom. thats why it looked so clean.

 

2) All manage to do so at speeds approaching freefall velocity, i.e. falling in around 10 seconds or so, where (he says) resistance from the undamaged sections (and their undamaged 47 central supporting columns) should have provided at least some resistance. Even if each floor had provided only a quarter of second resistance to the falling floors above, it should have taken over 24 seconds for them to fall. More realistically (he says) given the in-built redundancy of the central supports, it should have taken around 40 seconds (i.e. half a second resistance by each floor).

 

but the coloumns did provide some resistance. even if you use the more wacky numbers for collapse thats are thrown up you get an acceleration of 6.something m/s/s. hardly freefall.

 

also, the buildings did have redundancy but all this support was for a constant static load and a small amount of dynamic load from wind and people moving about. it was not designed to be able to withstand several thousand tonnes slamming into it. much like a sheet of paper can support a brick and you can move it around but if you drop it it plummets through the paper.

 

it was a normal collapse.

 

3) The controlled demolition hypothesis of Bulding 7. This (I'm told) only suffered external 'gouging' damage on one side and only burned on two floors, yet fell in the same manner as the towers (i.e. straight down into its own footprint and very quickly), and inconsistently with the damage it suffered. It apparently left a debris field radius of only 70 feet. The Oklahoma city bombing did much more catastrophic damage but a good part of the buiding remained standing.

 

yeah, a gouge that took of 18 stories worth of corner, to around 40-50 feet inside the building and setting the rest of the place on fire. there is no evidence of an explosion. just structural failure due to weakened supports on a damaged sector. Oklahoma involved a bomb. thats why it had a massive debris spread. IT HAD EXPLOSIVES. not wtc7.

 

4) Not strictly related, but odd. Apparently, the BBC released news of the Salmon brothers building collapse 20 minutes before it did. You can see the building in the background of the live report here.

 

never heard of that one.

 

if this wasn't you i would have went into a rant about nutcases.

[Glider]

if this wasn't you i would have went into a rant about nutcases.

Well, thanks for not doing so. As I say, I don't buy into conspiracy theories, but the thing that unsettled me this time was not being able to think of a reasonable response to the 'evidence' my mate presented (knowing bugger all about structural engineering).

 

I was tempted to go into a rant about nutcases too, but he seems to enjoy buying tequila so much (probably helps to get people to listen to him) and it seemed a shame to screw up a good thing at the time

 

PS Thanks for the (quick) reply too. Very helpful.

[insane_alien]

heh. i''m not a genius about structural engineering either. i know a bit about mechanics of deformation and fracture though. the conspiracy nuts always get basic stuff wrong. and completely ignore the more advanced stuff

[YT2095]

if I`m not mistaken, they were all structurally connected underground too, in fact there was a massive underground complex where you could go shopping etc... that connected these.

the shock of one falling would be like a massive earthquake and undermine the structural integrity of Anything connected by it.

like dropping a hammer on a table with a house of cards on it, it May not fall over, but it won`t be a safe as it was either.

[insane_alien]

thats a valid point to. there are harldy any earthquake proofing measures employed in NYC. and two 500,000 tonne buildings falling down so close is going to shake the ground.

[swansont]

Conspiracy theories are usually based on events not fitting preconceived notions or assumptions. When these assumptions (e.g. the extent to which the science/engineering is understood; that any event will occur in the most typical, ideal fashion; highly accurate information flows quickly in a crisis situation; people behave rationally and predictably under stress) are wrong, some people will erroneously leap to the conclusion that it was a conspiracy. Not being able to dismiss a claim of conspiracy is not the same as proving it exists.

 

I think the presence of conspiracy theories is, in fact, a conspiracy to divert us from the truth.

[Mag]

4) Not strictly related, but odd. Apparently, the BBC released news of the Salmon brothers building collapse 20 minutes before it did. You can see the building in the background of the live report here.

 

its easy to mistake buildings and get the wrong information during such panic.

[insane_alien]

mm its not hard to imagine the press taking a message of 'we think its going to collapse' and shoving it out as 'it has collapsed' because they misheard or something. even deliberately so they can say 'you heard it here first'

[Pre4edgc]

Well, my sister was checking something out about the twin towers, and this came up on the list in YouTube. I'm also not one for conspiracies, though I like making fun of them by making some up. But what do you think of this?

I'm not encouraging this as true, so please do not post as such...

[Glider]

All tall buildings flex in the wind. You can feel it.

 

I think the movement caused by a plane hitting the building would be enough to pop windows out and remove what were essentially big tiles from the walls.

 

Why only in the lobby? It's where the building joins its foundations and it's less flexible there. The movement higher up would have been shared between floors, in the same way that you can bend a stick quite a lot in the middle where it's free to flex, but if you bend it to the same extent at an end that's fixed (e.g. clamped in a vice), outer fibres will begin to crack and peel off.

 

The shock wave of the impact would have rippled down the more flexible parts of the building until it reached the more rigid section at ground level where, due to it's inability to move, damage would have occurred.

 

mm its not hard to imagine the press taking a message of 'we think its going to collapse' and shoving it out as 'it has collapsed' because they misheard or something. even deliberately so they can say 'you heard it here first'

That wouldn't surprise me in the least.

[insane_alien]

the movement caused by the planes would have been relatively small compared to the mvements caused by a strong gust of wind.

 

i don't know what caused that bang but from the location of the camera (and i presume microphone) the dust cloud should have appeared before the sound.

 

but i mean, its not as if any large chunks of building had fell down that could have made a lot of dust that could have been whipped up by the wind.

 

and, from the fact that the towers still standing, people were still being evacuated. i think one of them would have shouted out about someone setting off explosives in the lobby.

[bascule]

I'd ask anyone advocating the conspiracy (Glider, you might want to pass this on to your friend) to take a look at the counterpoint to their argument. I have certainly familiarized myself with the arguments of the "9/11 truth movement", watched Loose Change, and read quite a bit on the matter in general.

 

For starters, there's Screw Loose Change, a fact-checked version of the original movie:

 

http://screwloosechange.blogspot.com/

 

There's also Popular Mechanics issue on debunking 9/11 myths:

 

http://www.popularmechanics.com/technology/military_law/1227842.html

 

And debunking911.com

 

Specifically regarding WTC7 and the NIST report, the lack of a definitive theory of the building's collapse has been used by the 9/11 truth movement to argue a conspiracy. It's not acceptable that NIST did not put forward a theory because they did not feel they had sufficient evidence or research time to formulate one.

 

This video demonstrates the central argument of the NIST report, which was a prolonged structural collapse:

 

http://video.google.com/videoplay?docid=3132857754400064872

 

Here the collapse of a mechanical penthouse (demonstrating an internal structural failure) can be seen to occur a few seconds before the rest of the building collapses. We also see a second mechanical penthouse begin collapsing instants before the rest of the building.

 

We do know WTC7 was hit by large chunks of extremely hot, high velocity debris. This resulted in a fire which NIST argues subsequently resulted in the collapse of the building. The extent of the structural damaged caused by the debris and the exact role of the fire are not known with any degree of certainty.

 

Arguments that the collapse involved with explosives seem to hinge around the argument that no steel frame building in history has ever collapsed due to fire alone, therefore controlled explosives are needed to bring down WTC7. This is not only an argument from incredulity, but a strawman as no one is arguing that WTC7 collapsed due to fire alone. The NIST argument is that the building collapsed due to a combination of fire and structural damage from debris resulting from the nearby collapse of two monumental skyscrapers.

[Glider]

I'd ask anyone advocating the conspiracy (Glider, you might want to pass this on to your friend) to take a look at the counterpoint to their argument.

And therin lies the problem. It is in the nature of conspiracy theorists to deny themselves exposure to alternative explanations to their own theory.

 

Having said that, to be fair, I don't believe he's really that convinced anyway. I wouldn't class him as yer actual full blown conspiracy therorist, he's more somebody who likes to argue (a lot) whilst drinking.

 

Still, there's some very useful stuff there, thanks for posting those links.

[JohnB]

I've never really bothered with the whole WTC conspiracy thing and know b*gger all about structural engineering. (I don't think playing with Mechano counts. )

 

Concerning the Youtube video;

 

1. As has been said, the dust cloud at the base should have preceeded the sound by a few seconds at least. and

 

2. Since when are elevator shafts "hermetically sealed aka airtight"? Might I suggest that a blast could travel down the enclosed space of the elevator shaft? On reaching ground level it could blow the doors off the elevator and sweep through the foyer with indeed the force of a bomb.

[insane_alien]

there were also a lot of storage tanks around the building carrying fuel and such. its also not unreasonable that it was a transformer(not the optimus prime type) that got heated to combustion by debris and burning fuel flowing down the shaft.

 

even if the shafts were airtight(lol what a joke) i think having a plane flying through them is going to compromise that somewhat.

[Norman Albers]

I watched the Trade Towers being built, in the sense that every 2-3 months I drove between Long Island and Princeton University. I was moved by the skeletal structure of a few central steel members and a spindly-looking web for the floors.

[Phi for All]

I think the presence of conspiracy theories is, in fact, a conspiracy to divert us from the truth.

I truly believe this. I think a few real questions get spun into a mass of... erm, questionable questions and then the whole thing gets labeled a conspiracy theory. It should be a logical fallacy unto itself.

[bombus]

I don't believe the official story of the whole 9/11 affair. There is something very fishy about it. The question is though, how far does one travel down the conspiracy highway. Ultimately people end up with totally whacko theories, but as I've said before, those who stick rigidly to the official story and refuse to see the 'fishiness' are just as nuts in my opinion!

[insane_alien]

well, of course the official story is still incomplete, they're still investigating it aren't they? the official story won't be finalised till the results are available.

 

our only problem is with those who make outrageous claims that have zero evidence. like the 'fell at freefall acceleration' when it fell at something like 2/3 g type of claims.

[TinFoilHatMan]

I have been reading through this whole thread and it has went from some actual discussion to a down right bashing of anyone with a differing viewpoint.

 

Now say what you want but I can find 623 different architects and engineers who don't agree with 9-11.

 

http://www.ae911truth.org/

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Another thing, On Feb 9, 2009 The Mandarin Oriental Hotel caught fire and the fire spread throughout the whole building.

 

 

This is the aftermath of the fire, the building is completely burned on every floor.

 

 

The building still stands today and is gonna be fixed up to be a hotel again.

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Beyond that look at the layout of the WTC complex. Building 5 was smack dab in between 1, 2 and 7

 

http://www.foxnews.com/images/36149/1_22_wtc_layout.jpg

 

http://www.stagedterror.com/images/WTC%20Complex.jpg

 

http://www.libertyforlife.com/images/911/wtc-complex7.jpg

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This next site gets into WTC 7 very in depth.

 

http://www.studyof911.com/articles/winstonwtc701/

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[Kyrisch]

Now say what you want but I can find 623 different architects and engineers who don't agree with 9-11.

 

Appeal to authority is a fallacy unless you actually put forth the evidence that they endorse. Just saying that "these talking heads agree with me" is no good.

Another thing, On Feb 9, 2009 The Mandarin Oriental Hotel caught fire and the fire spread throughout the whole building.

 

 

This is the aftermath of the fire, the building is completely burned on every floor.

 

The building still stands today and is gonna be fixed up to be a hotel again.

 

... Don't you think that gasoline fuel would burn at a higher temperature than a normal blaze? C'mon.

[insane_alien]

the mandarin hotel was a completely different scenario.

 

no inital massive structural damage

nothing to dislodge the fireproofing

not even the same type of fire(fuels, accelerant, area alight at one time)

vastly different supporting structure

[bombus]

...As I say, I don't buy into conspiracy theories...

 

Some of them are true. Thats the big problem.

 

With 911 I'd guess most people know something aint right with the official version, but at one end of the extreme people say that simply the US Govt used it as an excuse to invade Afghanistan/Iraq, and at the other its down to the CIA/Illuminati/Aliens.

 

The truth is probably somewhere along the continuum - but where depends on ones level of paranoia!

[insane_alien]

yeah, people have went to some real crazy places with 9/11 although i'm almost positive some of them started off as satire but people took it as fact. like the one that they were taken down by nuclear icbms.