If the twin towers were left burning, could they soon collapsed?

Originally posted by Valhall
And then I'd like to point out one more factoid that I don't believe I've ever seen anybody share when discussing thermal degradation of steel strength...

it's not permanent. If the steel is allowed to start cooling back down, it follows the same strength curve back to ambient that it followed getting to temperature. So if you start with an 50,000 psi piece of steel at ambient, bring it to 250 C (and therefore decreased yield strength), and then burn up all the available combustible fuel and the fire passes on to another area allowing that piece of steel to start cooling. If it comes back to ambient it's going to have 50,000 psi yield strength again (especially when you're talking about less than an hour at the elevated temp).

Just thought I'd slip that in.


[edit on 7-30-2006 by Valhall]

But when it contracts from from the cooling process the sagged or twisted steel is no longer in its original shape. Do you think this can be a factor in things like shear forces..buckling and the ability to transfer loads as per design?
Just throwing that out there.

And furthermore, I'm not done.

Let's take this silly nonsense here:

Effects of Subsequent Fires and Impact Damaged Fireproofing:
A.Thermal Weakening of the Core:
•The undamaged core columns developed high plastic and creep strains over the duration the building stood, since both temperatures and stresses were high in the core area. The plastic and creep strains exceeded thermal expansion in the core columns.
•The shortening of the core columns (due to plasticity and creep)was resisted by the hat truss which unloaded the core over time and redistributed loads to perimeter walls.
•As a result of the thermal weakening (and subsequent to impact and prior to inward bowing of the South wall), the North and South walls each carried about10 percent more gravity loads, and the East and West walls each carried about 25 percentmore loads. The core carried about 20 percent less gravity loads after thermal weakening.

From here:

wtc.nist.gov...

Stand back while I hurl a major BULL$*** at these people.

Creep does NOT increase the deformation of a member under the same load. And what I mean by this is the following:

Once the plane impacted and knocked out whatever structural elements it knocked out, and the load of the upper floors of the building was redistributed onto the remaining core elements and perimeter elements - whatever deformation that caused - creep did not intensify. And the statements quoted above made by NIST implies it did. Creep does NOT increasing deformation, creep makes deformation permanent.

So if the planes had hit the building and knocked out the same elements and there was no fire and then you went in and rebuilt the knocked out elements (jacking the building up off the remaining load bearing elements, those load bearing elements would return to their original lengths. But with creep, if you came in to rebuild the missing elements and you jacked up the building off the remaining elements, they would NOT return to their original length. But they wouldn't be "more deformed" because of the creep...they just wouldn't return because they have had plastic deformation instead of elastic deformation.

For the NIST to claim that the hat trusses took more load and put it on the perimeter elements because of CREEP in the core elements is an OUTRIGHT LIE. And further to that! Let's pretend there was creep at all:

Creep

Temperature affects steel in another important manner. If a load slightly less than the elastic limit is applied at room temperature, the steel will elongate and, when the load is removed, will return to its original length. This elastic behavior will continue regardless of the number of loadings and regardless of how long the load remains in a single loading. If, however, an identical piece of steel is heated to some slightly elevated temperature and a load is applied, it is found that after a length of time the specimen will assume a permanent deformation even though the stress applied is below the elastic limit determined at the testing temperature, usin gthe relatively rapid tensile test. This phenomenon is known as creep, and while not fully explainable with our present range of knowledge, it is measurable and very important in steel applications where elevated temperatures are involved and deformation is not permissible. In some instances, a limiting creep extension of 0.1% in 10,000 hours may be allowed.

Steel and its Mechanical Properties, by George F. Melloy, B.S., Materials Engineering Institute, pp 20-21.

I'm sharing this and emphasizing the one statement to make everybody understand - just how damned slow creep is. But the major point here is this:

If the core columns, at 250 C to 450 C, still had enough residual strength left for the increased static loading, there would have been minimal shortening of the columns and it most likely would NOT have compensated for the thermal expansion they were experiencing at the same time. But to say "CREEP" negated the thermal expansion AND INCREASED the deformation is A LIE.

a lie a lie a lie. lie lie lie...liars.

[edit on 7-30-2006 by Valhall]

Valhall, disregarding how fast the buildings fell, have you ever noticed that all three buildings fell without visible changes in how fast they fell, from start to finish?

For example, would it have been possible to crush the Twin Towers with a falling mass? I think we can agree it would have been possible, given an endless reserve of energy, mass falling downwards.

But exactly how much energy would be required to crush the buildings from, say, floor 97, to the bottom floor, and into the basement? I think we can agree that it would take more energy to crush more floors, than less floors.

But what about this: How much energy would it take to cause a collapse in which the collapse itself appears not to slow down, indicating no diminishing kinetic energy?

When anything else that moves loses energy, it will slow down. A ball rolling will slow down before stopping, even if it rolls into someone's hand and comes to a sudden stop in the end. I know of no reason to think the WTC collapses should have been any different. The collapses, as far as one can tell from any/all videos, neither slowed nor sped up, the whole time. They started at a pace, and continued at that same pace, despite thickening columns towards the bases, the vast amount of mass being lost over the sides of the buildings, the amount of energy being lost in pulverizing all the concrete, etc. And pulverized floors, I don't think, would have the same effect upon falling onto other floors, as intact floors would. Dissociated steel beams and concrete dust just won't do near the same damage as an intact floor, even when the same amount of mass is there, and yet the collapse of WTC1 especially quickly became driven, by official theory, by a bunch of destroyed floors. Again, apparently without slowing down.


As a different perspective on the same oddity, BillyBob created a thread a while ago showing the collapse wave briefly ahead of free-falling debris beside the building. The debris passed the collapse wave as it accelerated, but the building collapse didn't appear to ever accelerate, but rather just started at a pace (which was initially faster than free-falling material still accelerating) and continued at that pace.


This is my main bone to pick with the collapse speeds. Not so much the times, but the lack of acceleration (meaning either speeding up or slowing down).

bsbray,

I understand where you're having difficulties, but to me the "harmonics" of the pancaking collapse could negated any change in strength as you got to the lower floors. I'm just telling you that for me, personally, I can't find anything in the actual collapse sequence that bothers me a lot. That doesn't mean I'm right, it just means, it makes sense to me.

But the collapse initiating in the first place is where my issues lie (that and the miraculous self-righting 30 story top of WTC 2). And then when you get the collapse initiation (that's hard to explain in the first place based on the data provided by NIST) in two separate buildings - acting just alike, but with completely different damage, and different loading conditions and in as short of time as it did...well, I'm not convinced by NIST's report.

In some instances, a limiting creep extension of 0.1% in 10,000 hours may be allowed.

I'm not clear on what this statement is saying.

The way I read it, its saying that in some instances a certain rate of creep may be allowed.

It doesn't seem to be stateing that .1% in 10,000 hour is a progressive rate of anything as a standard for creep.
When he states that 'in some instances'....'may be allowed'..what instances are those?..in what application?

Maybe I'm reading it wrong.

Originally posted by zappafan1

Hey I'd post all day long within the well rebutted Popular Mechanics parameter, which is totally absurd and focuses on red herrings while ignoring hundreds of PHds on Scholars for 911 truth and other independent viewpoints.

REPLY: Well rebutted? by whom? Jones?
So the structural and mechanical engineers et al, who wrote the Pop. Mech. article are somehow less knowledgeable than those you mention?

Hundreds of PHD's? I've seen no such number of those who agree with Jones (whose "presentation" was very poorly done; "Lame" might be a better word).

I've seen only one who has attempted to vet his theories.

Comment: Popular Mechanics had a hostile takeover just prior to the publication of the infamous 911 article. That hostile takeover was heavily sponsored by the government. The Vladimir Lenin lookalike, Chertov, has a brother who runs Popular Mechanics, a once credible source that currently has a conflict of interest regarding scientific objectivity.

No, you are reading it right. You are reading that if you design for an instance of elevated temperatures, you are to design such that you do not get more than .1% permanent deformation over 10,000 hours of elevated temperature. I'm not saying the WTC was designed to those parameters, I'm illustrating how very slow creep is.

Primarily creep is taken into account in high temperature, high pressure situations and typically where a member is in tension. (For the WTC we would be talking about "creep in compression set".) For instance, in high pressure piping (steam applications and such) the bolted members holding the piping sections together would have to be designed to prevent appreciable creep.

This makes sense because if a bolted connection between two sections of pipe is elevated in temperature, you rely on your thermal expansion of your various elements to prevent leakage. But if the bolting members experience creep (i.e. the extension due to loading during the elevated temperatures becomes a "permanent set"), then when the connection decreases in temperature (and the thermal expansion decreases), you're going to get a leak because the bolted connection can't stay tight.

[edit on 7-30-2006 by Valhall]

Thanks for the explaination.

How does the sudden unnatural forces factor into something like the towers. I mean like the sudden and violent deformation of the steel with sudden high temps applied i.e. a sort of instant 'permanent set'? I'm wondering mostly about how deformed steel members (deformed in ways we'll never know) affect the ability to transfer loads per design?

I'm just asking. If we're talking about a bolt becoming permanently loose, thats one thing. But if we're talking about a structure that depends on an intact system for stability, it would seem that alot of calculations get tossed into the air of unpredictability.

Any member damaged at the time of impact in a manner that changed its intended loading condition (whether that be through torsion or bending or partial shear) should be considered "gone" when trying to calculate the loss of structural integrity. Because there's nobody (including NIST) that can say what new state that damaged element was in after the impact. If you go to the presentation of NIST that I linked earlier, you will see they indicate elements that were completely eliminated and elements they considered severely damaged.

Any member damaged at the time of impact in a manner that changed its intended loading condition (whether that be through torsion or bending or partial shear) should be considered "gone" when trying to calculate the loss of structural integrity. Because there's nobody (including NIST) that can say what new state that damaged element was in after the impact.

So in your opinion did NIST underestimate the loss of structural integrity in their report?

Wait, rephrase your question to:

"In your opinion, do you believe the towers should have fallen based on the damage modeled by NIST?"

Answer: no.

I have no idea whether their model underestimated the damage. And since they won't share their data with anyone so that their methodology can be verified, we have to assume they are correct, and therefore full of crap. EDIT: Let me rephrase that...we have to assume their model is correct, and therefore their results are for crap.

See the sticky wicket they have themselves in?

[edit on 7-30-2006 by Valhall]

The towers were 1350 and 1360 feet tall. So let's start by using our trusty free-fall equation to see how long it should take an object to free-fall from the towers' former height.

Distance = 1/2 x Gravity x Time(squared)

or

Time(squared) = (2 x Distance) / Gravity


Time(squared) = 2710 / 32 = 84.7


Time = 9.2

So our equation tells us that it will take 9.2 seconds to free-fall to the ground from the towers' former height.

Using our simpler equation, V = GT, we can see that at 9.2 seconds, in order to reach the ground in 9.2 seconds, the free-falling object's velocity must be about 295 ft/sec, which is just over 200 mph.

But that can only occur in a vacuum.

Since the WTC was at sea level, in Earth's atmosphere, you might be able to imagine how much air resistance that represents. (Think about putting your arm out the window of a car moving half that fast!) Most free-falling objects would reach their terminal velocity long before they reached 200 mph. For example, the commonly-accepted terminal velocity of a free-falling human is around 120 mph. The terminal velocity of a free-falling cat is around 60 mph. (source)

Therefore, air resistance alone will make it take longer than 10 seconds for gravity to pull an object to the ground from the towers' former height.


Observations from 9/11

On page 305 of the 9/11 Commission Report, we are told, in the government's "complete and final report" of 9/11, that the South Tower collapsed in 10 seconds. (That's the government's official number. Videos confirm that it fell unnaturally, if not precisely that, fast. See for yourself: QT Real)

ut the "collapse" proceeded "through" the lower floors of the tower. Those undamaged floors below the impact zone would have offered resistance that is thousands of times greater than air. Recall that those lower floors had successfully supported the mass of the tower for 30 years.

Air can't do that.

Can anyone possibly imagine the undamaged lower floors getting out of the way of the upper floors as gracefully and relatively frictionlessly as air would?

www.911blimp.net...

Conclusions

In order for the tower to have collapsed "gravitationally", as we've been told over and over again, in the observed duration, one or more of the following zany-sounding conditions must have been met:

• The undamaged floors below the impact zone offered zero resistance to the collapse
• The glass and concrete spontaneously disintegrated without any expenditure of energy
• On 9/11, gravity was much stronger than gravity
• On 9/11, energy was not conserved

However, none of these physics-violating conditions can be accounted for by the official government conspiracy theory of 9/11, nor by any of the subsequent analyses designed to prop up the official theory of 9/11.

www.911blimp.net...

Here's the "911 Commission Report"

www.9-11commission.gov...

Show me where it says WTC 2 fell in 10 seconds.

You have had several people here point out to you that there are multiple video sources that show the collapse times of WTC 1 and 2 to be around 14 to 16 seconds. If your intent is to cling to your erroneous theories in direct opposition to facts - then go off some place and continue your obsession. But if you'd like to talk facts, we're all here trying to do that.

[edit on 7-30-2006 by Valhall]

By the way - prophet - aren't you the same character that argued with the half the board that satellite communications and radio communications can't take place in space and therefore every bit of the space missions are fake?

I'm seeing a pattern here.

In this photo:



Which top section of the WTC would hit the ground first.

Please review The Last Prophet's post above.

www.abovetopsecret.com...







[quote of Entire previous post removed]
Mod Edit: Big Quote – Please Review This Link.

[edit on 7/30/2006 by 12m8keall2c]

Originally posted by Valhall
By the way - prophet - aren't you the same character that argued with the half the board that satellite communications and radio communications can't take place in space and therefore every bit of the space missions are fake?

I'm seeing a pattern here.

Interesting. Double Speak.

You talk about "facts" and then spew verbal assault "made up for all I know". This is what FOX news does all the time.

I am not the person you refer to.

According to physics, in a perfect vaccum it should have AT LEAST taken 100 seconds for ANY of the 3 Buildings to fall.

18 seconds is ridiculous - but whatever.

sell crazy some where else.

The research came from the Scholars for 911 Truth. Peer reviewed by doctors of engineering and physics.

I found it:

At 9:58:59, the South Tower collapsed in te seconds, killing all civilians and emergency personnel inside...

They were wrong. It's about that simple. The 9/11 Commission was not the body doing the analysis on the WTC collapses anyway, so it's not like they are the authoritative body on the data surrounding the WTC collapse.

Simply put - they were wrong. The really neat thing about dealing with facts (versus delusion) is you don't get to use somebody's mistake to your advantage when the facts prove otherwise.

Originally posted by Valhall
Wait, rephrase your question to:

"In your opinion, do you believe the towers should have fallen based on the damage modeled by NIST?"

Answer: no.

I have no idea whether their model underestimated the damage. And since they won't share their data with anyone so that their methodology can be verified, we have to assume they are correct, and therefore full of crap. EDIT: Let me rephrase that...we have to assume their model is correct, and therefore their results are for crap.

See the sticky wicket they have themselves in?

[edit on 7-30-2006 by Valhall]

I was just basing my question on the fact that they differentiated between the levels of damage to the columns and your idea is that if they were damaged at all they should be thought of as 'kaput'.

I have to disagree a bit about the idea that not sharing? the input data =crap conclusions. That doesn't really track.

Who has asked for the information and what information was asked for? If a request was made for all million + bits, well you don't have to assume a cover up for refusing to set a precedent for all previous and future investigation by releasing data to anyone who asks.
I don't see how that makes the results 'crap'.