911 WTC collapse

Originally posted by Wolfpack 51
In a metallurgical investigation, in order for the structure to fall evenly, a unified heat source would be needed to weaken the support members evenly to a point that they would become elastic, unable to support the above weight.

Actually there are a lot more problems with that above statement than the misuse of the term “elastic.”

Wolfpack seems to be confusing the concepts of metallurgy and structural engineering. Metallurgy is a study of the basic properties of metals, whereas, it is Engineering that concerns itself with how any why structures stand or fall.

The term “unified heat source” is somewhat nonsensical. I am assuming that wolfpack means that the entire floor would have had to have been heated evenly in order for it to fail.

This is not true. When a column is no longer able to support the load that it is intended to support, that load just doesn’t go away. It is transferred to the adjacent columns and structural members. In this process, the loads on the other columns and beams can change dramatically. A column connection that was designed to be in compression may be put into tension by the shifting loads. Beams that were once supported on both ends are now cantilevered, and so on. Once a sufficient number of columns were no longer supporting the loads they were intended to, those loads would have shifted to the other columns. But this shift would not have been even.

If all of the columns on one exterior wall buckled inward to the point where they were no longer supporting the loads above, those loads would have shifted to the nearest un buckled, undamaged columns. At some point, the demand on those columns will exceed their capacity and they too will fail. This causes the loads , plus the additional loads from the newly failed columns to transfer to the next undamaged column, until it too fails and so on down the line.

The thing is, once a certain point is reached, this happens fairly quickly. It just seems like it happens all at once.

Originally posted by Wolfpack 51At a precise moment the energy of the above weight would fall evenly and continue to the ground.

Like I said, .it happens so quickly that it seems to happen all at once.

Originally posted by Wolfpack 51
This is not possible with the fuel that was present.

The fuel has nothing to do with it. Not in the sense that you are implying. The fire was hot enough to weaken the core columns and to cause the floor trusses to sag. This in turn caused the exterior columns to buckle inward.

Originally posted by Wolfpack 51
Some members may have weakend, but not all of them to give the pancake fall that we witnessed. Without all members being close to the same measure of elasticity, the building would have not fallen evenly, nor to the ground.

I think you simply fail to truly appreciate the enormous loads these columns were carrying. Once a runaway failure started, gravity pulled the building straight down.

Originally posted by Wolfpack 51
If bringing a building down of this size was as easy as igniting Kerosene on a floor with some weight above it, why do engineers go to school to study physics and load bearing technologies to do precise demolition work?

In order to prevent damage to the adjacent buildings, like WTC 6 and WTC 7, The Winter garden, The hotel, the bank, etc.





[edit on 4-1-2006 by HowardRoark]

i'd agree with you howard, except that it did just happen suddenly, and didn't just 'seem that way'.
and like i said elsewhere, the fire was moving around, and the intense parts were in different places at different times. once steel cools, it regains it strength, and will be able to bear the same load as before it was heated(approx. the same load).

Originally posted by billybob
once steel cools, it regains it strength, and will be able to bear the same load as before it was heated(approx. the same load).

Not if it's buckled.

Even at room temperature, a buckled column won't support a load.

Lumos, you are and continue to be in error with your assumption that I stated: "and glass is very elastic while rubber is not" (your quote). My quote was thus: "Rubber has a low level of elasticity."

My comment was made within the context of this thread wherein someone was using the term elastic incorrectly. You agreed.

You falsely equated "modus of elasticity" to elasticity itself, that's the only problem here. Your long list of credentials doesn't impress me, especially when your actions don't seem to back it up.

Incorrect again. I pointed out the difference between the two. I qualified that difference in the following sentence.

*As it pertains to engineering* the modulus of elasticity of a material defines its ability to maintain its dimensional stability once acted upon by another force.

After all, the point I was making was, and still is, germane to the steel the other poster was talking about.

Do you want to argue whether metals are isotropic or not, or can we skip that part?

I utterly have no idea what you mean by the quote above. Depending on the metal it can be either isotropic or anisotropic. Your point?

With regard to my typo in "constutents," is there a point to be made other than a poorly veiled ad hominem attack or a petty Parthian shot?

Dude, our discussion is over. You didn't look too well. If you really want to reiterate the points all over, feel free to do it...alone.

You didn't look too well.

Once again, another error.

Originally posted by HowardRoark

Originally posted by billybob
once steel cools, it regains it strength, and will be able to bear the same load as before it was heated(approx. the same load).

Not if it's buckled.

Even at room temperature, a buckled column won't support a load.

agreed. and the strength difference would be a function of force vectors, which would be a function of angular stress. ie. 180º bent to 90º would give fifty percent the original vector support. by the same token, a beam bent to .5º off the original axis, would lose that much strength in that direction(it would however, now ACCOMODATE that much of an increase in the direction perpendicular to the design spec's load bearing intention. this strength would not disappear, in other words, but rather be focused in a different direction)
so, how much NET buckling, and to what degree, are we thinking of, here? i'm trying to visualise how it could happen. it would be amazingly fascinating for me to actually come to the same conclusions about the two big tower collapses, as the official tripe(HIGHLY improbable) preaches. (although, let's face it, there is no 'solid' official tripe. a lot of strong(as in authoritative) suggestions, but that's it. brazent zhou(or whatever) says one thing, fema says another, and nist, yet another. 'laymen' defenders of these VARIOUS theories, regarding collapse mechanisms, make up their own stuff, like the 'syringe theory' and whatnot, often contradicting the official story in their zeal to protect it. that's what happens with complicated lies.)

i know what you are saying here. that nothing would move(much), until the final 'straw' was placed on the 'camel's back'. the problem is, we are talking about STEEL here, which is a pretty malleable material, and will bend a great deal before it breaks.

considering the redunacy factor, the non-uniform factor, and the fact that most of the tower was nearly as good as new, it just doesn't add up that the tower would be bolt straight one second, and in freefall the next. (it is the official lie that uses freefall to translate PE into KE, no?)

Originally posted by billybob
and the strength difference would be a function of force vectors, which would be a function of angular stress. ie. 180º bent to 90º would give fifty percent the original vector support. by the same token, a beam bent to .5º off the original axis, would lose that much strength in that direction(it would however, now ACCOMODATE that much of an increase in the direction perpendicular to the design spec's load bearing intention. this strength would not disappear, in other words, but rather be focused in a different direction)

I'm not sure I follow you there chief.

Are you saying that when a column buckles the loss of it's load bearing capacity is a simple function of the degree of the buckle?

Actually I think it is a bit more complicated than that.

www.efunda.com...


www.efunda.com...

Maybe we can get zamboni to calculate this for us.

wow! great site!

still. what i'm saying is true in principal. the relationship is not a simple linear ratio, however, it is still a function of amount of deformation.

also, that formula applies to a single beam, and does not account for the dynamic loadshifting, shape preserving abilities of a lattice.

cooler perimeter, hotter interior, not as much fuel(flammable live load stuff) in the core.

i don't know. still doesn't add up, at all.

we've also got a great deal of secrecy involved, and a great deal of reluctance to release vital evidence to public inspection. do you think that is in the spirit of peer review and good science? 'cause, i don't.

and how did tower seven fall so symmetrically, so quickly? literally sucked to earth, it was.

[edit on 5-1-2006 by billybob]

Originally posted by billybob
wow! great site!

If you don't want to register, you can zap the cookie.



Frankly, while I can grasp the basic concepts, the math gets a bit obtuse.

(or it's late and I'm tired)

i used to toss cookies. i think it's like trying to swat flies when someone is shooting a machine gun at you, if you know what i mean.

here's a quote from an external source, physorg.com, basic physics thread

i bolded some key bits...

Look, I am not a scientist, nor a physicist, nor structural engineer.
I am a Boilermaker, Shipbuilder, Blacksmith Forger and helper. Union. Now a contractor on military facilities. I build steel storage tanks for jet fuel. A few years ago, a typhoon blew through, and I got to watch a Mobil AST, with @ 1,000,000 gallons of diesel in it, get hit with lightning, the grounding failed, and the million gallons BLEW!!
Well, for a diesel fire that is. it simply caught fire, burned itself out after 4 days, blackened the steel. Catch that? One million gallons of diesel fuel, burned for 4 days, didn't melt squat. Tank, 1/4" steel, never melted.

Yet HUGE core I-beams, supporting the elevator and utility shafts, were VAPORISED at the WTC towers? Stop, I'll wet my britches laughing.

I've melted, welded, forged, bent, twisted, repaired sheared, punched, formed, plated, blasted and coated just about every metal you see used commonly in industry and construction, for over 32 years. I 've welded many a steel I-beam: purlin clips, joining plates, you name it.
I ask you plainly: you know the explosion you see after the second plane hits the tower? a_ht, what caused that?
Tell me you believe, like me, it was the JP-8 (yes, I work with jet fuel daily, too) contained in the jet's tanks, correct? Huge explosion, you say you were there that day? Your father? He see this huge fireball? What was it?
Because, if it was the kerosene (JP-8, acts just like diesel, you can put it right in your diesel tank, works great, low flash point of 140 deg) that did explode that way, that you state so assuredly melted steel, explain how it reconstituted itself after exploding, and put itself back inside the building, and THEN what?

Ran down 90 floors to melt the "uninsulated I-beams"? What? "Shook" it off by jet impact? Are you kiddin' me? When the jet hit, it did not even knock folks down in the building below!!! What nonsense, a_ht!!

Because I KNOW the dimensions of a 14,000 gallon fuel tank. About the size on one of the many offices on the floor hit. That's all, a_ht. The size of one office.

Yet, you would have me believe NOT my own eyes, that see an explosion of huge proportions caused by the impact of the jet plane, but rather a tale that says exploded fuel turned back into liquid form, and only

Okay! I misused elastic in the post.

I was not refering to the ratio of stress-strain in the region below the proportional limit on the stess-strain curve, which is the modulus of elasticity.

To state it simply, as you know, it was to relate to the point that the steel would yeild its strength due to heat.

I have not researched the exact point that steel would yeild but I do know that it has a phase change at 723 degrees celsius(1333 degrees fahrenheit). Ok not a phase change but it is the critical temperature between the pearlite phase field and the austenite phase field.

The issue is that the planes did not have enough energy to elevate the steel temperature to the point of yeilding in the manner that was seen.

The first tower to fall was the last one hit. Most of the fuel from the plane went out the corner of the building.

The fact that there was no examination of the metal leaves open the actual cause of the collapse. That leaves us to only debate the cause. Only metallographic examination of the metal would reveal actually what happened to cause the buldings to collapse.

Big words and calculus formulas are intimidating and help those that have some knowledge of these things intimidate the "common person". The towers do not need either of these items. Those that just use plain common reasoning can argue that if tower 1 took the full impact and fuel of the airplane into its structure, and tower 2 took at the best 1/4th the fuel and only a partial impact onto the main middle structure, then tower 1 should fall first. Also since tower 2 was hit on a corner of the structure, if it was to fall, then it should fall at the weakest area. It did lean when it fell, but amazingly still came straight down, but unfortunately, it fell first.[ I would be willing to bet that was a uncalculated error in the detonations]

I enjoy seeing the educated argument to prove the impossible. I feel we may never know the truth, so we will be left to bebate in vain.

Originally posted by Wolfpack 51
The fact that there was no examination of the metal leaves open the actual cause of the collapse.

There was some, provided by NIST.

Observations of paint cracking due to thermal expansion. Of the more than 170 areas examined on 16 perimeter column panels, only three columns had evidence that the steel reached temperatures above 250 ºC: east face, floor 98, inner web; east face, floor 92, inner web; and north face, floor 98, floor truss connector. Only two core column specimens had sufficient paint remaining to make such an analysis, and their temperatures did not reach 250 ºC. ... Using metallographic analysis, NIST determined that there was no evidence that any of the samples had reached temperatures above 600 ºC. (p 90/140)

Source. Or look at NIST's actual report by the page numbers given in the above quote (NIST 90, 140). Either will work.

So of at least 170 perimeter column samples, only 3 went beyond 250ºC, and those apparently did not approach 600ºC.

Neither did any core column samples. None of those samples even showed signs of heating beyond 250ºC, but we're apparently not told exactly how many core column samples were examined.

250ºC doesn't really even hurt the integrity of the steel.... At all. Cached Source.



Image source.

On the above image, line up 250ºC (1/4 of the way between the 200 and 400 degree designations) with the amount of strength loss. That's apparently what brought down the towers.

How does jet fuel burn? I thought fuel exploded in big quantities? which is what looked like happened when the majority of the fuel went up in a massive fireball OUTSIDE of tower 2

A jet fuel explosion doesnt sound like it would cause sufficient prolonged temperatures to affect steel of this magnitude in any way at all, infact if the fire was so intense why did a fire chief make it to the floor of impact (near as damn it) and radio in to say it would be controlable? shouldnt he of been incinerated by the intense heat?

Has anyone here had a go with thermite? I have on a small scale and it could quite easily account for the "molten steel" still being uncovered days/weeks after the collapse, and its not an explosive reaction so would be perfect for this scenario coupled with a few selective charges rigged up throughout the buildings.

Jet fuel burns quite nicely. Jet fuel VAPOR explodes.

If I drop a match into a bucket of petrol then it will just burn and wont take my head off?

So where did all that "vapour" come from that went up in a big fireball outside of the tower?

Planes fly with empty fuel tanks all the time. They give them the amount of fuel they need to get to their destination, and a little bit more for a reserve, and leave the rest of the tanks empty.

I am glad to see that there are still people interested in the towers collapse.

There are no resonable explanations given by the government as to the actual reason the towers collapsed.

There are not large stock piles of the debris to examine properly to determine that there were no means other that the planes that contributed to the collapse or towers 1 and 2.

There to my knowledge is no physical pieces left of wtc 7 to examine.

I hope that many people keep looking for the true answer, and that maybe in the looking we find enough evidence to get the real reason the towers collapsed.

Many wonder if the government was involved in this conspiricy, why, what reason could they use to justify something as horrific as self inflicted terrorism.

National Security. Imagine that back 10 to 20 years ago a group of high ranking American officials met in a forum to talk about the dangers to our nation that were real and very possible. In this discussion the danger of nuclear attack to was brought up and that one possible danger was from the middle east region. How would we be able to defend our nation from such a threat. We would need a military staging point in the region with access to ports for supplies.

The question then arises of how to get such a military base established in a region that would not willingly allow this. The answer is with a military action in that region, thereby our middle eastern allies would not look bad to their fellow neighbors when the military arrived.

The next question was how to get the American people behind such a move. Also how to present it to the world in a manner that would look somewhat legitimate. The answer was an attack inside America with civilian casualties. If this line of thinking is used, then manipulating an anti-American organization would be wise. Get this group to do something horrific, and plan the disaster so it would be devistating.

This is one way of justifing government involvment. The question would be do we lose thousands of lives, so we can prevent millions of deaths and protect our nation from nuclear damage or do we do nothing and try diplomatic solutions only.

Given this line of reasoning, I would side with the government. I do not imply that this is what happened, but it is something to think about since the answers to the collapse and other events are shaded to say the least.