9/11 Conspiracies

[CabinetMaker]

Is there enough kinetic energy in a wing to slice through steel and concrete?

Yes. Keep in mind that the aluminum skin on the wing of an airplane is much thicker than the average soda can that most people seem to associate with airplanes. The skin can be up to 1" thick and aircraft grade aluminum is a different alloy than the aluminum used for cans. It is harder. The wings of a plane have to carry the weight of the plane so it needs to be structurally sound. They are designed using the principles of torsion boxes. You have an internal structure of ribs and spars with an aluminum skin. Torsion boxes are very light and very strong and rigid so it is entirely possible for a wing to cut through the thin steel skin of the WTC.

As the plane breaks apart, the energy is still present in all those pieces of plane and building blasting through the building. Remember, those bits and pieces were propelled into the building with over 1.5 million tons of force. That will blast through the relatively thin concrete around the stair wells. A large wrecking ball swung slowly against a concrete will will break it. The planes had more energy than a wrecking ball.

One last thing to keep in mind is that the WTC towers did not have the traditional steel frame that most sky scrapers are built with. The design of the WTC eliminated the skeleton resulting in wide open floors that were revolutionary for the time. To achieve this, the building was designed as a column within a column. There was a central column made of concrete and an outer column made up of the steel building skin. The two columns were connected by steel open web joists resulting in a very stable structure. So when the planes hit this structure it need only cut through the skin and the central core to significantly weaken the building structure. As the fires burned, it further weakened the steel skin until it was no longer able to support the weight of the remaining building above. When the remaining steel failed, the upper part of the building was dropped straight down on to the lower part of the building. Once again we see what kinetic energy can do. The weight of the upper building dropping several unsupported stories created enough kinetic energy to greatly exceed the loading design for live weight and dead weight and a caused the failure of the remaining structure.

 

[CabinetMaker]

So yes or no (not to be blunt), it was common knowledge prior to 9/11 that the towers would withstand a hurricane, but not an airliner full of fuel?

As far as the general public is concerned, its still not common knowledge. TO the engineers who designed those buildings, it was far less of a surprise.

 

[Nihilo]

As far as the general public is concerned, its still not common knowledge. TO the engineers who designed those buildings, it was far less of a surprise.

Given that the WTC was Al Qaeda's pièce de résistance on 9/11, and that it was known to someone beforehand that such an outcome was possible, why wouldn't we consider that information as above top secret?

 

[ok doser]

Given that the WTC was Al Qaeda's pièce de résistance on 9/11...

i'm not sure that's true

the pentagon was a much more psychologically significant strike and iirc, the shanksville plane was headed for the white house

 

[CabinetMaker]

Given that the WTC was Al Qaeda's pièce de résistance on 9/11, and that it was known to someone beforehand that such an outcome was possible, why wouldn't we consider that information as above top secret?

Buildings have been designed to survive an airplane strike since a B-25 flew into the side of the Empire state building in 1945. There is nothing secrete about it.

 

[Nihilo]

i'm not sure that's true

the pentagon was a much more psychologically significant strike and iirc, the shanksville plane was headed for the white house

I don't know that the Pentagon strike did much to Americans, surely if the WH was leveled that would have meant something (though the President wasn't there as we know now), but there was nothing like the whole world watching those towers crumple to the ground like a massive house of cards. :idunno: Opinions....

 

[Nihilo]

Buildings have been designed to survive an airplane strike since a B-25 flew into the side of the Empire state building in 1945. There is nothing secrete about it.

Well that's what me and STP are asking about, if it was well-known that buildings were designed to withstand an airliner full of fuel then why did the towers go down, and both of them? Clearly it didn't even take a precision strike, since the two planes impacted at completely different heights and from completely different angles.

 

[CabinetMaker]

Well that's what me and STP are asking about, if it was well-known that buildings were designed to withstand an airliner full of fuel then why did the towers go down, and both of them? Clearly it didn't even take a precision strike, since the two planes impacted at completely different heights and from completely different angles.

The buildings were designed to sustain an airplane strike and they did. The buildings were designed to withstand a combat a fire which they could do for a while. Either one of these happening is a first order failure and the buildings could survive them. However, when these two happened together it was a second order failure and the buildings were not designed for to deal with that. Few buildings are because of the huge cost increase that designing to second order imposes on design and construction.

I think to the general public, it is not well known that the buildings are designed to survive an airplane strike. The people who design them know, we are paid to know, but the public is blissfully unaware of what engineers do and why they do it. Personally, I think the terrorists thought that flying a plane into the side of the building would knock it over. Very, VERY few people actually understand how the physics of how the world works.

 

[Nihilo]

The buildings were designed to sustain an airplane strike and they did. The buildings were designed to withstand a combat a fire which they could do for a while. Either one of these happening is a first order failure and the buildings could survive them. However, when these two happened together it was a second order failure and the buildings were not designed for to deal with that. Few buildings are because of the huge cost increase that designing to second order imposes on design and construction.

I think to the general public, it is not well known that the buildings are designed to survive an airplane strike. The people who design them know, we are paid to know, but the public is blissfully unaware of what engineers do and why they do it. Personally, I think the terrorists thought that flying a plane into the side of the building would knock it over. Very, VERY few people actually understand how the physics of how the world works.

I'm still not getting a straight answer here. Was it known before 9/11, that an airliner full of fuel impacting one of the towers (of course assuming that the fuel ignites upon impact!), would cause it to collapse like a controlled demolition?

 

[CabinetMaker]

I don't know that the Pentagon strike did much to Americans, surely if the WH was leveled that would have meant something (though the President wasn't there as we know now), but there was nothing like the whole world watching those towers crumple to the ground like a massive house of cards. :idunno: Opinions....

The terrorists won a huge victory that day and the buildings collapsing were only a small part of it. We enacted a very unconstitutional law, the Patriots Act, under which we traded our freedom for imagined security. Been to the airport lately? I remember walking to the gates to meet my uncle when he flew into town. Now I can't get near the gates if I have my 1" blade pocket knife in my pocket.

“Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety” -Be Franklin

We traded our liberty to the government for safety. What cowardice by the American people.

 

[CabinetMaker]

I'm still not getting a straight answer here. Was it known before 9/11, that an airliner full of fuel impacting one of the towers (of course assuming that the fuel ignites upon impact!), would cause it to collapse like a controlled demolition?

You have gotten the best answer that is possible. Some people knew, most did not. Those most familiar with building design understood the risks associated with second order failures.

 

[Nihilo]

The terrorists won a huge victory that day and the buildings collapsing were only a small part of it. We enacted a very unconstitutional law, the Patriots Act, under which we traded our freedom for imagined security. Been to the airport lately? I remember walking to the gates to meet my uncle when he flew into town. Now I can't get near the gates if I have my 1" blade pocket knife in my pocket.

“Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety” -Be Franklin

We traded our liberty to the government for safety. What cowardice by the American people.

I agree with that. Airports are unpleasant enough without the excessively secure security lines, but thankfully, the security people are still Americans too, and most of what I've seen, they feel our collective pain and just try to make it as tolerable as possible under their mandate.

 

[Nihilo]

You have gotten the best answer that is possible. Some people knew, most did not. Those most familiar with building design understood the risks associated with second order failures.

OK, then I still wonder who exactly did know, and whether or not that information was treated as top secret or not, because that information wound up being integral to a very grave breach of our national security.

 

[quip]

Internal structural failure cause by fire weakening the two main supports of the building. If you watch the videos of the collapse you can see the internal failure by the way the building starts to move and the way the windows start to break. Really fascinating study in structural failure analysis.

Interesting indeed...went down like a pancake!

 

[CabinetMaker]

Interesting indeed...went down like a pancake!

No, it didn't. The building wasn't construed in such a way as to allow for a pancake collapse.

Here is a video that shows the full collapse sequence of WTC7.

 

[CabinetMaker]

OK, then I still wonder who exactly did know, and whether or not that information was treated as top secret or not, because that information wound up being integral to a very grave breach of our national security.

Commercial buildings are not considered part of national security. You can go down to the local county offices and pull blue prints of just about any building you are interested in. Blue prints are public record unless the building is truly a classified government facility.

 

[quip]

No, it didn't. The building wasn't construed in such a way as to allow for a pancake collapse.

Here is a video that shows the full collapse sequence of WTC7.

Yes, it did.

 

[ok doser]

i remember debating someone way back when who insisted that the WTC buildings fell faster than freefall :darwinsm:

 

[CabinetMaker]

Yes, it did.

Your compilation video cuts out the first 6 seconds of the collapse and does not address the internal collapse that started before the walls collapsed. When you look at the entire video you see that the penthouse structures collapsed into the building several seconds before the exterior walls begin to collapse. By definition, that is not a pancake collapse.

 

[CabinetMaker]

i remember debating someone way back when who insisted that the WTC buildings fell faster than freefall :darwinsm:

Some of the un-exploded demolition charges went off after the building started to fall and the explosions drove the debris downward at faster than free fall speeds. :rotfl: