NOVA - how the towers fell on 10 p.m. MDT

[TrogL]

Probably other times in your timezone.

I had a long talk with a professional architect who teaches architecture and used the design of World Trade Centre in his lessons.

He says given how cheaply the building was constructed and the manner of their construction they behaved exactly as their design said they would when they fell.

He said the Nova documentary got it exactly right.

[karlschneider]

1. Your friend is right. I predict there will be some jumping in here

claiming there were explosives "planted", that jet fuel doesn't burn hot, that Satan sent devil X-rays into the WTC towers, ad nauseum.
There's no shortage of nutcases in the world and inevitably some of them find their way to DU.

[TrogL]

2. I know. There's an equally valid argument

to theirs that the towers were brought down by the power of prayer and meditation.

Prove otherwise.

(on edit, don't mind me, I'm mad 'cause my other thread died)

[karlschneider]

4. Well, my dear friend Pat ROBert$on said it was GAWD's revenge...

must be the case.

[hang a left]

3. what nutcases aren't allowed here Karl? says who?

[karlschneider]

5. I submit that all nutcases are ALLOWED here. And the sane ones reserve

the right to identify them. Is that okay with you?

[bpilgrim]

7. what if we just have QUESTIONS? are we still to be considered 'NUTS' karl?

i've never seen buildings fall in their own footprints before unless it was done by CD have you?

btw: what happened to WTC7?
http://globalfreepress.com/movs/911/wtc-7_collapse.mpg

peace

[karlschneider]

9. Jeezus fucking christ. If you wreck the basic structure of a building, or

anything else, it's going to fall DOWN. We do live under the well established paradigm of GRAVITY. That's what makes shit FALL DOWN (toward the center of the planet) Surely you are trying to shit me...??

Give me a fucking break here. It isn't as if we don't have enough evidence to indict Shrub and his cadre of criminal bastards, yet some people seem to have an obtuse need to invent forty five layers of conspirical idiocy.

The fucking buildings fell down because they were FUCKIING DAMAGED to the point of collapse!!!!!!!!!!!!

Why is that simple engineering principle so hard to assimilate?????

AAAAAAAAAAAAAARRRRRRRRRRRGGGGGGGGGGGGHHHHHHHHHHHHHHH


Edit: fixed a typo. Posted originally and erronouesly because the whole thing is so damned stupid.

[pretzel4gore]

17. i recall clearly

on one of the networks (i dumped cnn cuz they TOO fulla crap pre 911!) the way one tower was LEANING, and i mean big time...you could see it on the tv! the thing literally looked ready to fall, and one of the anchors was saying 'oh god it's gonna fall over' etc)
somehow or other the towers both went down like sandcastles the bush's peed on(!) straight down...
almost all the hijacked jets had small passenger loads, the pentagon jet hit the side where least numberr lives could be affected....it was as if the BRAINS behind 911 was trying not to hurt too many americans....
course, i think KAL 007 was a global hawk technology job too ):!

[TrogL]

19. You can't see buildings lean properly on TV

To take architectural photos they have to use a special lens that removes the lean factor. On TV all buildings look like they're leaning.

[pretzel4gore]

27. millions must have seen the item....

you know a straight line? the towers formed straight lines up/down...then gradually as coverage ongoing a noticeable bend developed...(too bad archival photos of the news coverage aren't available)...we're talking a major network (abc i think) with a woman anchor helping guy.....she did say (paraphrase) 'omg it looks like it's gonna fall over!' so it wasn't just me(!)

[TrogL]

37. This is your source???

a news anchor watching TV?

Unless you are using a special tilt and shift lens (more about that later), you get this.



A lens like this



allows you to modify the focal plane to eliminate the paralax problems inherit in ordinary lenses.

Ordinary TV cameras do NOT have that capability. Hence, you cannot tell, looking at a TV picture, if a building is leaning unless it's drastic.

Given the number of people watching the buildings from all sorts of angles, somebody besides this one newswoman would have noticed.

[maha]

32. They didn't lean all that much.

I wasn't watching on TV. I had a clear view from a high-rise on West 17th street. What leaning went on was very slight.

[TrogL]

11. Gee, implosion works

Implosion works by wrecking the inside of the building and the rest falls down and goes boom.

A big fire wrecked the inside of building 7 and it fall down and go boom.

What don't you understand?

[never cry wolf]

13. What buildings have you seen fall OUT of their footprints

and what were the circumstances. Besides, they did not fall in their footprints, numerous buildings were damaged by falling debris at a good distance away and you can't have two buildings in one footprint.

As an architect we have had 30' high masonry walls under construction under a wind storm and all the debris is withing 10' usually, and that is under a lateral force. They do not just tip over and fall down go boom.

[TomNickell]

25. If they are idiotic questions.....

If the questions are stupid, and people give you perfectly reasonable explanations, and you just keep on with the stupid 'evidence' and cite nutcases and refuse to listen to serious people....

Yeah, NUTS is a good description...

[maha]

30. What happened on 9/11...

...had never happened before. There's nothing to compare it to. You can't say, well, buildings just don't fall down like that. No buildings of that size and construction were ever hit with that kind of damage.

[Liberal_Dog]

6. I'll Jump In

The North Tower was hit at 8:46 and collapsed at 10:30 AM-- 104 minutes later.

The South Tower was hit at 9:03 and collapsed at 9:59 AM-- 56 minutes later.

Assuming that the Twin Towers were composed of basically the same building materials and that the jet fuel from Flights 11 & 175 were similar, then the same physical processes should have been at work in both of the Towers.

So, why did the South Tower collapse almost twice as quickly as the North Tower?

[karlschneider]

8. Because the death rays were primarily directed toward the South Tower.

See how simple it is?

[Liberal_Dog]

15. Cute Little Non-Response

nt

[TrogL]

16. It's called sarcasm

Often a sign of disrespect, often earned.

[Liberal_Dog]

28. Disrespect This!!!

At no time did I say that I believed that there were bombs in the WTC. I am, however, open to that possibility. I simply was asking a logical question.

Why did the South Tower collapse twice as quickly as the North Tower? I need more of an answer than "Fire works in mysterious ways".

We know the construction layout of both Towers and we know where the planes hit each Tower. Give me a logical reason why one Tower would collapse twice as quickly and I would be perfectly willing to accept it.

Also take note that in no post that I have made in this thread have I disrespected anyone or called anyone names. If the only way that you guys can defend your position is to be disrespectful of others, perhaps you need to re-think a few things.

[JHB]

36. Mostly because it was hit lower...

...which meant lots more weight above the fire zone. More weight = more stress on remaining and damaged supports = a lowered threshold of damage required to cause structural failure.

It's not mysterious.

[TrogL]

38. Shit happens

It's a firefighter's expression.

We just went through a bad season for forest fires up here. The fires actually burned down some houses in Kelowna, B.C. Some houses got burned and others next door weren't affected. Why did the fire behave like this?

"Shit happens".

[karlschneider]

39. I'm not disrespecting anybody. The South tower was struck in a very

different way. Much lower and tangentially. So the damage done to it was potentially (and ultimately) more serious, since there was FAR more weight above the damaged portion. Translation: There was more heavy shit overhead, ready to fall down. Toward the ground.

And that is the -main- reason it fell first. I am not an architect, but I am an engineer and I have a pretty good grasp of structures (my degree is Aeronautical Engineering) and there is absolutely and unequivocably no doubt in my educated mind that those buildings collapsed from heating of the trusses. If anybody wants to discuss that, let's have another thread.

And right about now I'm beginning to seriously wonder why I'm even bothering to defend science against idiocy. Let me think....yep, it's enough.

[TomNickell]

26. NO. NO. NO!

It was explosives planted by gov't agents the night before!

They cleverly set off the charges out of order to drive the Conspiracists crazy with frustration.

[TrogL]

10. Because fire is a chaotic event

It doesn't occur evenly over all places at all times. Pure happenstance will cause it to be cooler on the weakest point of one building and stronger on the other.

[maha]

31. That's easy.

The plane that hit the South Tower hit it lower. That changed several variables.

[Gloria]

12. The Ric Burns documentary on the the Towers, aired again last night

(or was it Friday night) on PBS had somebody on who said it was actually the PAPER in the buildings that burned....so much paper, that the temperatures rose so high that the damaged sections gave way. The jet fuel burned hot, but only for a few minutes. After that, it was all paper, plus carpet, computer casings, etc. But mostly...PAPER.

The one tower was hit closer to the top than the other tower. Which may explain the different collapse times. Also, as the first tower fell, the other tower apparently swayed and then righted itself. So the impact of the plane crash plus the collapse of the first tower may have also been a factor.

[never cry wolf]

14. That is exactly correct.

The impact damage was different and weakened the base structure of each in a different manner. The additional load above the damaged area of the second tower because it was hit lower doomed it to a quicker fate.

[maha]

33. Yes, of course it was paper.

The jet fuel itself didn't burn long, but it ignited all the stuff inside the offices -- furniture, people, carpeting, paper.

I keep running into flaming idiots who say, well, jet fuel wouldn't have been burning all that long. Do they think the towers were solid steel? Have they never been in an office building?

[never cry wolf]

18. Ahhhh, back on topic

The guy you talked to is correct in that I believe that Nova got it right too. The only thing I may quibble with is saying it was built cheaply. All construction is designed to be as economical as possible, except for interior finishes and aesthics. The structural engineers who can safely engineer a building utilizing an economy of steel and concrete thru innovation and brains are the successful ones.

[TrogL]

21. He said they scrimped

for example on the insulation for the core.

[never cry wolf]

23. Oh that.

I agree with that. Spray on fireproofing for a large part is a joke, a cheap way to meet fire code. The stuff gets tested and approved under laboratory conditions at UL but in reality it is applied by humans and really does not adhere very well. Unfortunately, at the time there was little other choice and it is still used today because it is alot cheaper than the intumescent type coatings that really do a much better job. Other options are encasing the steel in drywall, VERY expensive or in concrete which is not practical for buildings that tall, they tend to weight too much.

[Atlant]

29. The other issue with the spray-on fireproofing...

The other issue with the spray-on fireproofing is that it
is designed to help the steel resist an ordinary fire (and,
properly applied, it can do that fairly well).

It ISN'T designed to stay on the steel after the
impact of a 767 hitting the building at several hundred
miles per hour. A very large amount of the fireproofing
was almost certainly blown off the steel by the impact of
the planes. After all, it's just lightweight, frangible
stuff with no particular structural strength; you can
knock it off with your hands.

Absent the fireproofing, the steel would certainly suffer
in the consequent fire.

Atlant

[never cry wolf]

34. Exactly right

Also, generally it is applied before the finish trades start and alot gets knocked off during hanging of ceilings, ductwork, sprinkler piping, etc. Over many years it gets compromised but no where near what the impact would have caused.

[TrogL]

20. Reminder: it's on now

[never cry wolf]

22. It's also on streaming video

at I believe www.pbs.org.

[TrogL]

24. Website

http://www.pbs.org/wgbh/nova/wtc/

[protect freedom impeach bush now]

35. agree with program

as one who has spent a few years working in hi-rise
construction, not with prime core contractor, but with the
following new construction of interior finish (offices, etc)


at lot of these buildings seem rather filmsy.

light-weight air-enhanced concrete poured into floor pans
that rust easily, sometimes the concrete thickness is so
thin that electrical floor pentetrations do not meet the
needed concrete thickness for fire ratings.

I've seem concrete as thin as 2" in the floors on hi-rises, and
this was construction done by the countries top bldg General
Contractors. This was on 50th floor or so.


EVEN though engineered for 'strength', JUST try something
really simple ---

just jump up & down a couple of times on the concrete floors in high
rise building -- watch and feel the floor shake.

likely safe, but shows just how flexible these building are constructed....again this is for a structural steel structure,
not a re-enforced concrete column structure.