An email from a Conspiracy theorist, and I have no idea how

[Undesired Walrus]

Given my bubble video, somehow, I have no idea how, a truther called "Heath" who calls himself a structual engineer has found my email address. I really am amis to how this is possible, as I believe e^n put up my video on his server.

Conspiracy!

Anyway, You are better than this stuff than me. Help me out a little please?

OK. There's two ways to make a tower collapse vertically downwards - 1) suddenly destroy a section so that part of the tower suddenly falls on the lower sections causing a collapse or 2) evenly weakening a similar section continuously. As parts collapse away more of the tower is weakened until it's all gone.

You will notice the conspiracy theory uses method 1) (bombs in the basement or wherever) while the official report uses 2) - the fire weakening the steel and causing the floors to collapse.

If the fire had weakened the steel supporting a floor (a claim that is very open to debate in itself) it would have had to be the case that all of the supports of that floor gave way at the same time to create a floor that falls 10 feet. You can tell me how many supports each floor had but I suspect it was a lot - statistically all of them failing at once is impossible and so the more likely scenario is that the floors collapse gradually - no big shock and no collapse.

What's more likely is the tower burning until the section with the fire was just a tube and then keeling over (remember the orientation of the exterior steel girders make them very resistant to heat deformation under gravity. A horizontal beam will sag but a vertical beam will not.)

I bet there have been computer simulations done to try and see what happens. I don't suppose you know of any do you?

[uk_dave]

OK. There's two ways to make a tower collapse vertically downwards - 1) suddenly destroy a section so that part of the tower suddenly falls on the lower sections causing a collapse or 2) evenly weakening a similar section continuously. As parts collapse away more of the tower is weakened until it's all gone.

You will notice the conspiracy theory uses method 1) (bombs in the basement or wherever) while the official report uses 2) - the fire weakening the steel and causing the floors to collapse.

He's already forgotten about the damage caused by the plane impact

If the fire had weakened the steel supporting a floor (a claim that is very open to debate in itself)... Bollocks, as any self respecting structural engineer knows since they have to deal with fire protection to steel members on a daily basis
... it would have had to be the case that all of the supports of that floor gave way at the same time to create a floor that falls 10 feet. You can tell me how many supports each floor had but I suspect it was a lot - statistically all of them failing at once is impossible and so the more likely scenario is that the floors collapse gradually - no big shock and no collapse. utter rubbish. The fire affected a number of floor trusses made up of thin steel sections. These weakened, sagged and caused their connections to the outer columns to pull those columns inwards. The columns then reached the limit at which their connections could resist the pull away from upright and failed catastrophically. This resulted in the floor falling onto the one below, overloading it and causing it to fail.

What's more likely is the tower burning until the section with the fire was just a tube and then keeling over (remember the orientation of the exterior steel girders make them very resistant to heat deformation under gravity. A horizontal beam will sag but a vertical beam will not.)

Is he suggesting that the fire would have consumed everything, including the floors until the tower was just a hollow tube?:eek:
And then fall over....like....a..........a.......... tree?

I bet there have been computer simulations done to try and see what happens. I don't suppose you know of any do you?

what a fool.

[uk_dave]

Having re-read his tube comment, I now see that he is probably suggesting that the floors would all collapse internally but that the structure would remain standing until someone at ground level leaned on it.

No structural engineer would display such a blatant lack of understanding of an engineered structure.

[MRC_Hans]

Given my bubble video, somehow, I have no idea how, a truther called "Heath" who calls himself a structual engineer has found my email address. I really am amis to how this is possible, as I believe e^n put up my video on his server.

Conspiracy!

Anyway, You are better than this stuff than me. Help me out a little please?


OK. There's two ways to make a tower collapse vertically downwards - 1) suddenly destroy a section so that part of the tower suddenly falls on the lower sections causing a collapse or

Incorrect. The natural way for any structure to collapse is vertically downwards, in the direction of gravity. For a structure to collapse in any other way, i.e. keel over, something must act to transfer the vertical force of gravity into a howizontal direction.

2) evenly weakening a similar section continuously. As parts collapse away more of the tower is weakened until it's all gone.


Incorrect. Parts do not collapse away till they are all gone, they bend or otherwise deform so the force is transferred to the remaining members. When the sum of the force on the remaining members exceed their strenght, they fail catastrophically.

You will notice the conspiracy theory uses method 1) (bombs in the basement or wherever) while the official report uses

That is only some of the CTs, but OK.

2) - the fire weakening the steel and causing the floors to collapse.


This is not equal to the formulation of #2 above. This second formulation of #2 is, however, correct.

If the fire had weakened the steel supporting a floor (a claim that is very open to debate in itself) it would have had to be the case that all of the supports of that floor gave way at the same time to create a floor that falls 10 feet.

1) No, it is not under serious debate.

2) The rest is a strawman. Once enough supports fail for the remaining to be overloaded by the redistributed weight, they will fail in (very) rapid succession.

You can tell me how many supports each floor had but I suspect it was a lot - statistically all of them failing at once is impossible and so the more likely scenario is that the floors collapse gradually - no big shock and no collapse.


The scenario is wrong. Try this: Suspend a heavy weight from a rope (no need to suspend it very high, half a foot will do ;) ). The rope should be one with a breaking strenght of about twice the suspended weight.

Now start cutting the rope, fibre by fibre. Do you need to cut them all before the rope breaks and the weight falls? Answer: No, when you reach the point where the remaining fibres can no longer carry the weight, the rope breaks.

What's more likely is the tower burning until the section with the fire was just a tube and then keeling over (remember the orientation of the exterior steel girders make them very resistant to heat deformation under gravity. A horizontal beam will sag but a vertical beam will not.)


If it is weakened it will, but we have proof of the mechanism of how the "tube" was breaking down: Several pictures and videos show how the sides of the tower around the fire zone are pulled inwards: The sagging inner structures excerted a horizontal (inwards) pull. As long as the inner structures (floor trusses) remained rigid, they transferred the load to the outer girders vertically, but once they started sagging, they pulled inwards.

I bet there have been computer simulations done to try and see what happens. I don't suppose you know of any do you?


Yes, the effect of sagging trusses (both from being heated and from stuff collapsing on them) has been shown in computer simulations. They precisely imitate the actual observations.

Finally, on "keeling over":

Collapsing buildings can, and sometimes do, keel over and fall more or less on their side. However, the process of keeling over requires the falling structure to rotate from its original, vertical, orientation. Such a rotation can only happen if there is some force acting on it, and this force must be powerful enough to transfer the pull of gravity for long enough to impart a rotational movement of the falling mass.

The idea that if you hack away the supports of a building from one side, then it must keel over is fundamentally flawed. For it to happen, the surviving supports must be strong enough to carry the weight of the structure above them, while bending as a hinge, for enough time that a rotational movement is initiated. This requires a redundance of strength that is not present in a very large building.

Hans

[Alferd_Packer]

A horizontal beam will sag but a vertical beam will not.

A vertical stuctural member is called a column, not a beam.

Columns "squash" under heat deformation.

[The Doc]

Looks to me like you have someone pretending to be a structural engineer. Either that or a structural engineer that got his degree from a box of Cheerios.

[Gravy]

Looks to me like you have someone pretending to be a structural engineer. Either that or a structural engineer that got his degree from a box of Cheerios.I agree about the pretending. I always laugh at the "everything would have had to fail simultaneously" canard. The deniers always expect the forces of nature to operate on their schedule. In their world things can't fail sequentially but rapidly. Clunkity-clunk!

[MarkyX]

I remember getting these emails by so-called "structural engineers" as well. One guy who emailed me said that the fires in the towers didn't go higher then 200 degrees C, and I simply asked him "You're telling me that all the material burning, open air, and the jet fuel burning would be not hot enough to cook a pizza" ? He said yes.

We've all seen examples of 9/11 deniers pretending to be heroes or scientists like "Guy Razor" to "Mike the EMT". This shouldn't be a shock to anyone.

[T.A.M.]

Well keep a dialogue with him, then simply ask him for his full name and university he got his Engineering degree from. If he actually gives you the info (highly doubtful) it would be easy enough to check.

To be honest, this letter stinks so much of a fake, that it may not even be worth your time to do the above.

TAM:)

[Loss Leader]

For what he's proposing, it seems like he's assuming the towers were built in a traditional skeletal framework which is just ... wrong.

[NoZed Avenger]

For what he's proposing, it seems like he's assuming the towers were built in a traditional skeletal framework which is just ... wrong.

I disagree. He'd have to make major revisions and many corrections before I would be willing to concede that he was merely "wrong."

[kookbreaker]

Remember, in the trooth movement its OK to lie about being an engineer when you are not. Its all for the trooth!

[kookbreaker]

BTW, If I were you I would reply using the info you've gotten here, then insist he prove in some form that he has the degrees he claims. Note to him that you should not have to put up with liars from a 'truth' movement.

[Undesired Walrus]

I agree about the pretending. I always laugh at the "everything would have had to fail simultaneously" canard. The deniers always expect the forces of nature to operate on their schedule. In their world things can't fail sequentially but rapidly. Clunkity-clunk!

Hooray your new signature Gravy!

Seen him around Manhattan recently?

[The Silver Shadow]

At least you get something from a "structural engineer." I'm still receiving hatemail on Facebook and I have to laugh at some of them because the twoofers can't string a sentence together and yet they claim they have the answers!

Anyhow, like TAM said, ask for his degree and where he graduated from. If he gives you the name of anywhere, check to see if it's a Diploma Mill
http://en.wikipedia.org/wiki/Diploma_mill
:)

[Darth Rotor]

I agree about the pretending. I always laugh at the "everything would have had to fail simultaneously" canard. The deniers always expect the forces of nature to operate on their schedule. In their world things can't fail sequentially but rapidly. Clunkity-clunk!
In re your sig link to Annie Hall, I can still recall a favorite line from that underwhelming movie, and sure enough, it's early in the fillm:

ROB
Let's get the hell outta this crazy city.
ALVY
Forget it, Max.
ROB
We move to sunny L.A. All of show business is out there, Max.
ALVY
No, I cannot. You keep bringing it up, but I don't wanna live in a city where the only cultural advantage is that you can make a right turn on a red light.

At the time, it was a good gag, but it has lost something in context, sadly.

DR

[chippy]

At least you get something from a "structural engineer." I'm still receiving hatemail on Facebook and I have to laugh at some of them because the twoofers can't string a sentence together and yet they claim they have the answers!

Like who? I could fire back at them.

[BillyRayValentine]

For it to happen, the surviving supports must be strong enough to carry the weight of the structure above them, while bending as a hinge, for enough time that a rotational movement is initiated.


I know you understand this, but I would clarify one thing so as not to confuse the truth-bots. The issue isn't so much rotation, but the horizontal shifting of the section's center of gravity. Rotation, in and of itself, does nothing to alter the location of an object's COG. (Not the object's COG, per se, but the location of its COG relative to a fixed point in space.) Only some manner of lateral force can do this.

Looking at the south tower collapse (plenty of unambiguous videos exist), we can see that the top section was, in fact, imparted with some rotational spin at the moment of collapse. The east side buckled first, and the building immediately tilted in that direction. And at least momentarily, the uncollapsed portion did indeed act as a hinge and shifted the section's COG. The operative word, however, is momentarily. As soon as the COG was shifted even a small amount, the top section and its hundred thousand tons of bulk was no longer centered and properly distributed over the support structure. Complete collapse ensued on all sides, as it had to. After that first moment, the hinge effect (lateral force) was over and gravity ruled the day.

In fact, the manner of collapse began working against this residual (and negligible) lateral momentum almost immediately. An observation that rarely gets noted is that after the building started rotating to the east, the corner along the eastern side of the collapsing section immediately began knifing through the building below. It essentially behaved like a wedge, and with several predictable results. First, debris was violently ejected to both the east and west. Second, forces began working against the "spin" of the collapsing section almost immediately. The net result was a gentle and slowing rotation as the section fell. And any lateral momentum that remained from the first moments of the collapse was all but arrested.

[The Silver Shadow]

Like who? I could fire back at them.
I usually delete them, but I have two that I haven't yet sent to the trash bin. I have replied to them all...

[Undesired Walrus]

And he replies!


etc etc...

This may be true for cricket balls but it certainly aint for buildings. Ask any Structural Engineer and they'll tell you that it's actually very hard to get a building to collapse vertically downward.

In response to the rope with a weight
What a pointless example. A building is a far more complicated system than a rope with a weight. Think about this - a cardboard box with a big weight on top of it. How does it collapse? Well what a surprise! it kinks in one side and keels over.

I do find it quite funny that someone could be as moronic as you are being thinking that you're coming up with good arguments to support your view when in actual fact they are just like you - much to simple to be of any use.

For every engineer you'll find to say one thing you'll find another to say the exact opposite (that's the thing with engineers. They're basically physicists that aren't clever enough to do proper physics.)

As for your strong interest in a topic you can't even spell, I'm afraid I can only snort derisively at you. Consider it done.

After the plane strike the buildings were what's called a chaotic system. I did have a think about trying to explain that but I don't think I'll bother to be honest. you'll just have to take my word for it that the most important property of chaotic systems is that a very small change in the initial conditions (the position of the plane strike. The scale of the fire and the distribution of mass above the weakened section) produces a very large change in the final state of the system, in this case the building. The probability of the buildings collapsing vertically is vanishingly small because there are very many more ways for it to topple sideways that the one vertical collapse.

Of course, you can identify with vanishingly small things much more easily than I can.

????? Any opinions??

[Pardalis]

Ask any Structural Engineer and they'll tell you that it's actually very hard to get a building to collapse vertically downward.I'm not an engineer by any stretch of the imagination but this sounds like bullocks. Aren't controlled demolitions usually done vertically and downwards???


Of course, you can identify with vanishingly small things much more easily than I can.What a pedantic pr*ck

[Alferd_Packer]

a cardboard box with a big weight on top of it. How does it collapse? Well what a surprise! it kinks in one side and keels over.


This idiot must live in a cardboard box. this is what you get when you have free internet access at the public library.


For every engineer you'll find to say one thing you'll find another to say the exact opposite (that's the thing with engineers. They're basically physicists that aren't clever enough to do proper physics.)

Obviously he has never met any real engineers.

[Alferd_Packer]

you'll just have to take my word for it that the most important property of chaotic systems is that a very small change in the initial conditions (the position of the plane strike. The scale of the fire and the distribution of mass above the weakened section) produces a very large change in the final state of the system, in this case the building. The probability of the buildings collapsing vertically is vanishingly small because there are very many more ways for it to topple sideways that the one vertical collapse.


This guy learned all about this subject from Jeff Goldbum in the movie "Jurasic Park."

Too bad he never grasped the concept of strange attractors.

[Drudgewire]

but I don't think I'll bother to be honest.

Can't blame you. No sense in starting now.

[deep]

I'm not an engineer by any stretch of the imagination but this sounds like bullocks. Aren't controlled demolitions usually done vertically and downwards???


Yes, they are. I suspect that he meant "collapse without explosives".

A building is a far more complicated system than a rope with a weight. Think about this - a cardboard box with a big weight on top of it. How does it collapse?


Hmm, I just tried this- the box not only collapsed vertically, leaving hundreds of small pieces of cardboard behind, but the styrofoam inside was reduced to dust and blown all over the room. Then, a short time later, the box of Cheerios on my kitchen counter collapsed.

[Reality Believer]

I would point anyone who wants a good, concise explanation, to this clip from "World Trade Center - Rise and Fall of an American Icon"

This is the Gene Corley clip. I think the important part is when he talks about removing lateral support for a column. This is a key failure mode.

1Bg8iDaDV-A

[Alferd_Packer]

I'm not an engineer by any stretch of the imagination but this sounds like bullocks. Aren't controlled demolitions usually done vertically and downwards???


Well, not allways. If you have a monolithic structure like a large chimney, a grain elevator or a silo, they sometimes elect to tip them over in a certain direction. The key word here is "monolithic."

[grmcdorman]

Well, not allways. If you have a monolithic structure like a large chimney, a grain elevator or a silo, they sometimes elect to tip them over in a certain direction. The key word here is "monolithic."True. The four smokestacks of the Lakeview Generating Station here in Mississauga were destroyed not long ago (yes, using controlled demolition). There's some nice pictures of the stack demolition at Wikipedia (linked above). The main building was just destroyed last month (and it didn't tip over).

ETA: Even then, the stacks didn't fall like a tree, as the troofers would claim; they were mostly in their own footprint!!!111!eleventy!1 :D (at least it looks that way from the photos).

ETA 2: I take that back: SZOkOT5w7SQ

Note that the blasts from the charges are audible, even for these relatively small structures.

[beachnut]

There are a few crazy people who will not take the time to understand 9/11. If this guy says he is an engineer, the school needs to remove his degree.

[Myriad]

After the plane strike the buildings were what's called a chaotic system. I did have a think about trying to explain that but I don't think I'll bother to be honest. you'll just have to take my word for it that the most important property of chaotic systems is that a very small change in the initial conditions (the position of the plane strike. The scale of the fire and the distribution of mass above the weakened section) produces a very large change in the final state of the system, in this case the building. The probability of the buildings collapsing vertically is vanishingly small because there are very many more ways for it to topple sideways that the one vertical collapse.


What you are overlooking is that the chaotic system you describe has an attractor. I thought about explaining what an attractor is, but I don't think I'll bother. You'll have to take my word for it that the attractor for this system is a big pile of rubble centered in the building's footprint.

Also note:

I don't think I'll bother to be honest.


Indeed.

Respectfully,
Myriad

[Undesired Walrus]

This guy is really pissing me off. Can you help me compile a response to shut him up once and for all?

I am currently sitting in front of my computer shaking my head at how someone with an IQ of more than 80 (at least) can fail to grasp what I'm trying to say so completely.

Are you honestly trying to tell me a mass suspended from a string is more like the WTC buildings than a box. Actually the WTC pretty much was a box with a central core so the cardboard box example is not a bad thought experiment. If you put a stinking great weight on top of a cardboard box, much like the situation the WTC towers found themselves in, the box will kink on one side and the weight will fall off sideways. Tell me that it won't. Go on!

What was so cool about the towers was just as you say. There was no skeleton but the exterior supported the building along with the core (which did have girders within it, incidentally) In order to make the tower collapse vertically then you'd have to take out a whole horizontal section of the exterior which I'll let you get away with even though i still have doubts about the fire. The floors, perhaps but not the exoskeleton.

What I will not let you get away with is the core. Where did that go ehh? Even if the floors collapsed causing the exoskeleton to fall as well (dodgy) then the core should still have been sticking up. how did that collapse mr. NIST report?

If you asked me why the exoskeleton was being pulled inwards as it was collapsing I would guess that the core itself had collapsed. That would certainly explain why the core wasn't left there. It would also explain the witness reports of secondary explosions and the reports of floors being closed for 'maintenance' in the weeks leading up to 11/9/01.

I tell you what really stinks, even more than the main collapses of the twin towers is the other building that collapsed - WTC 7. It is just way too convenient that the offices of the CIA and the USSEC just happened to be destroyed, losing records of goodness knows what. Why 7 and not 3, 4, 5 or 6 which were closer to the twin towers?

[R.Mackey]

Cardboard boxes are dominated by shear strength. The core of the WTC Towers was quite the opposite.

Some of the core columns survived the initial collapse, but fell about ten seconds afterwards. This is barely visible on the videos. It also proves just how little shear strength they had. The core was designed to carry gravity loads only, and the wind forces were borne by the perimeters. It's all in the NIST report.

Since the exterior columns were pulled in over the course of tens of minutes, it makes no sense for it to have been caused by core collapse.

I think his observations on IQ are unfounded. :D

[Garb]

Why 7 and not 3, 4, 5 or 6 which were closer to the twin towers?

Umm am I wrong or didn't a couple of those buildings get destroyed anyways?

[AZCat]

What kind of cardboard boxes is he using for his experiments? When I place a weight on top of a cardboard box in my house, the top of the box fails and the weight falls through.

Of course, it could be the fact that cardboard boxes make [rule8] analogies for structures such as the WTC towers.

[Pardalis]

Of course, it could be the fact that cardboard boxes make [rule8] analogies for structures such as the WTC towers.

Ya think (http://www.dkimages.com/discover/Home/Sports-Games-Recreation/Toys/Creative-Play/Unassigned/Unassigned-338.html)? ;)

[kookbreaker]

He's rather loud and arrogant for someone who lies about being an Engineer...then he says this (whilst claiming to be an engineer):



For every engineer you'll find to say one thing you'll find another to say the exact opposite (that's the thing with engineers. They're basically physicists that aren't clever enough to do proper physics.)

What is 'proper physics'? I wouldn't trust an Engineer to model a collapsing star, but I don't want Stephen Hawking designing the world trade center for that matter.

Did you point out this guy's flagrant lies about his 'profession' yet?

[LashL]

Umm am I wrong or didn't a couple of those buildings get destroyed anyways?

You're not wrong. They all did.

[PhantomWolf]

I'd suggest he sets his cardboard box on fire and then watch the direction it collapses in.

[AZCat]

Ya think (http://www.dkimages.com/discover/Home/Sports-Games-Recreation/Toys/Creative-Play/Unassigned/Unassigned-338.html)? ;)

!

That's pretty cool, actually. If you had some claymation to go with it, I might buy whatever explanation of the collapses you proffered (but then I'm gullible when I'm tipsy).

[BillyRayValentine]

you'll just have to take my word for it that the most important property of chaotic systems is that a very small change in the initial conditions (the position of the plane strike. The scale of the fire and the distribution of mass above the weakened section) produces a very large change in the final state of the system, in this case the building.

Wrong. The principle of sensitive dependence on initial conditions is only relevant when considering what happened in the collapse zone, which was almost entirely within the building's footprint. Change the location of one desk on the 80th floor, and beams that were ejected outward might have burst inward instead, that kind of thing. It's actually a useful concept, considering the many truthers who seem to think that if we'd just investigate enough, we'd be able to account for the movement of every atom that day.

The "very large change in the final state of the system" to which he refers is only accurate in terms of where individual pieces of material in the collapsing and final debris piles were located, relative to where they would have been under different initial conditions. The notion that the aggregate result - a gravity-driven, vertical collapse - should have been different is nonsensical. The collapse area was a big 'ole mess, with a million different girders, slabs, chunks, etc., going in a million different directions. It was chaos, but the chaos pertained to the relative movements of the individual pieces of debris. This has nothing to do with, and in no way invalidates, the (observed) cumulative result of the process.

He brought up a relevant concept by accident, 'cause he sure as hell doesn't understand it. Ask for his thoughts on attractors.

[Unfit4Command]

At least you get something from a "structural engineer." I'm still receiving hatemail on Facebook and I have to laugh at some of them because the twoofers can't string a sentence together and yet they claim they have the answers!

Anyhow, like TAM said, ask for his degree and where he graduated from. If he gives you the name of anywhere, check to see if it's a Diploma Mill
http://en.wikipedia.org/wiki/Diploma_mill
:)

I've been involved in quite a few 9/11 Discussions on Facebook. The one I really remember was a thread with a title of something along the lines of "9/11 debunker's, come out or shut up." I missed the first few days of the thread, so several posts were already made and several of those posts included false claims. I quickly wrote a response that took up about 3 Facebook entries, and a few hours later someone deleted the thread :( I messaged all of the admins of the group and all of them said they didn't delete the thread...so the only other person who could have deleted it is the person who originally made the post, unless the admins lied.:)

A few others were pretty interesting. I'm so used to posting here around several educated debunker's that I was surprised to see the idiocy on Facebook. Oh well, I never got any mean messages :)

[Dave Rogers]

????? Any opinions??

Yes, but I can't post them here because of rule 8.

After the plane strike the buildings were what's called a chaotic system. I did have a think about trying to explain that but I don't think I'll bother to be honest. you'll just have to take my word for it that the most important property of chaotic systems is that a very small change in the initial conditions (the position of the plane strike. The scale of the fire and the distribution of mass above the weakened section) produces a very large change in the final state of the system, in this case the building. The probability of the buildings collapsing vertically is vanishingly small because there are very many more ways for it to topple sideways that the one vertical collapse.

The conclusion doesn't follow from the premises. He's saying, in effect, that the behaviour of the collapse was unpredictable because it was chaotic (itself not true, as Myriad and BillyRayValentine pointed out), therefore he can predict how the collapse should have proceeded. He hasn't justified his statement that there were "very many more ways for it to topple sideways" either. Basically it's an argument from incredulity.

I suggest you just block his e-mails. If he wants to debate on a public forum, that's a different matter, but there aren't exactly any lurkers to convince in an e-mail exchange.

Dave

[Alferd_Packer]

What you are overlooking is that the chaotic system you describe has an attractor. I thought about explaining what an attractor is, but I don't think I'll bother.


If you stop and think about it, 9/11 truth is a chaotic belief system with a strange attractor. . .



(rimshot)

[Undesired Walrus]

Can someone give me a few good smackdowns here to mix around my answers? I'd really like to get rid of him (Without blocking).

And someone more clever. I know what is wrong with his arguments, but I cannot phrase it as beautiful as you lot.

An attractor is defined to be a point in a dynamical system where a moving object does not move from even if it is perturbed. In this case the attractor is the ground in it's entirety - not just the base of the building.

I've just re watched the videos and I can't see any core. There's a good shot from the side where the wind blows the dust away from the camera and I really can't see a core. Presumably if the core had blown over there would be more sticking up from the wreckage than there was (you can tell me how high the wreckage was - 4 floors?)

I was suggesting you use your brain and imagine what would happen if the base of your cardboard box was strong enough not to fail. You're honestly telling me that a mass attached to a string makes a better analogy than a box? Come on man, you can do better than that.

you said yourself that the wtc was 95% office space. Regular offices may contain computers, desks and staplers but generators and canisters? I don't think so. Why would the offices in one of the biggest cities in the world need canisters?

I repeat: Why 7 and not 3, 4, 5 or 6 which were closer to the twin towers?

Who's going to take legal data from a wreck like this? any data recovered from a hard drive is going to incomplete and not reliable enough to be used for a legal purpose, like proving someone owes you money for example. Thats not to mention paper records at all.

What are you saying? You really aren't that clever? You don't come across that way (most of the time )

More questions - what about the pulverised dust? No mechanism for the production has been proposed (apart from a bomb). What about the squibs? what about the fact the NIST report is based on analysis of just over 200 pieces of debris. Where did the rest go?

[Belz...]

I repeat: Why 7 and not 3, 4, 5 or 6 which were closer to the twin towers?

He said he was an engineer ? He should understansd that low buildings don't react like tall ones. Also, he might note that none of those are still standing.

[uk_dave]

Can someone give me a few good smackdowns here to mix around my answers? I'd really like to get rid of him (Without blocking).



Just tell him he's right. Tell him he's convinced you. You feel stupid for having been so blind.

Then encourage....no.. INSIST that he produces a document setting out in the clear, concise and informed language he has used so far, the truth behind the wtc towers collapse. INSIST that he must send it to every professional body representing architects, structural engineers and demolition experts both in the US and overseas. Tell him you're with him and that you've heard about this email from a guy called mike who was an EMT in NYC at the time of the crime.

Reiterate, he MUST come forward with his evidence and stand shoulder to shoulder with the common decent folk (wipes away a tear) around the world who are enslaved by this fiendish deception by the powers that be and the worlds media. HE CAN DO NO LESS!! And if those professional bodies fail to publish it, or in the (un)likely event that they tear it to shreds with reasoned argument, he must take a stand against them and resign whatever membership he holds. He must withhold tax from the evil government and state publicly his intent to see them overthrown!!!

Viva la revolucion!!!!

[BillyRayValentine]

If you stop and think about it, 9/11 truth is a chaotic belief system with a strange attractor. . .



(rimshot)

Ain't dat da twoof...

[nicepants]

And he replies!
????? Any opinions??

Part of your response should be:

"What a pointless example. A building is a far more complicated system than a cardboard box."

Since that was his criteria for deeming your rope example "pointless".

ETA: As far as the box "tipping over", I guess that would explain why every time I try to stand on a cereal box, the box falls to one side and I slide off....oh wait...

Also, if this guy is an engineer, why is he so secretive with his qualifications? His definition of an attractor sounded very much copied & pasted to me.

[Heiwa]

I am a structural engineer specialized in shipbuilding. I have inspected many ships built of steel damaged by fire and overload of various kinds. None of these ships or their structures has ever collapsed by fire. Deformed, yes. I have some observations regarding the WTC2 collapse that may be of interest:

The NIST NCSTAR 1-6D report suggests that the WTC2 collapse was due to the following:

"Buckling of East Wall and Collapse Initiation

With continuously increased (sic) bowing and axial loads, the entire width of the east wall buckled inward. The instability started at the center of the wall and rapidly progressed horizontally towards the sides. As a result of the buckling of the east wall, the east wall significantly unloaded, redistributing its load to the softened core through the hat truss and to the south and north walls through the spandrels ( …). The section of the tower above the buckled wall suddenly moved downward, and the building tilted to the east ( …).

The section of the building above the impact zone tilted to the east and south (observed at about 7° to 8° to east and about 3° to 4° to south, …) as column instability progressed from the east wall to the adjacent south and north walls. The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued (sic)."

According to other NIST reports the total mass above was supported as follows:

50% - by the 47 core columns.
12.5 % - by the south wall columns (abt 80)
12.5% - by the east wall columns (abt 80)
12.5% - by the north wall columns (abt 80)
12.5% - by the west wall columns (abt 80).

About 80% of the wall and core columns were intact after first impact according NIST and the tower structure carried the mass above. Then there were fires in the office spaces between the core and the outer walls. The outer wall columns were always cooled by fresh air so they were unaffected by the heat.

We are told that the east wall, that carried 12.5% of the mass above, buckled inward due to axial loads some minutes before the collapse, which BTW are constant and not increasing, as suggested. The buckling deformation is not big as there is still some support from floors inside.

We are then told that the east wall significantly unloaded but not how much. Let's say that 50% of the load on the east wall that originally carried 12.5% of the total mass above, i.e. 6.25% of the total mass above is now redistributed to (i) the core, and to the (ii) south and (iii) north walls through connecting structure.

So 6.25% of the total mass above is redistributed. What happens?

Say that 50% of that or 3.125% of the total mass above is redistributed to the core; it will then carry 53.125% of the total mass above. Thus the load on the core increases 6.25% after the alleged redistribution.

We are told that the core is 'softened' which is not scientific but maybe it was affected by heat. However, half of the core columns were far away from any fires so they could hardly have been affected. But as the core columns had resisted the fire so far, a load increase of 6.25% due to redistribution could not make the core collapse!

25% of the redistributed load or 1.5625% of the total mass went into the south and north walls respectively that now each carries 14.0625% of the total mass above. Thus the load on the south and north walls increased 12.5%. These walls were not affected by fire as they were cooled by fresh air. There were some damage to the south wall, but again it did not collapse at impact, so a load increase of 12.5% will make little difference. No deformation of any kind is seen on the north and south walls after redistribution.

Global collapse could therefore not ensue due to such load distributions because there were too much redundancy and safety factors built into the outer wall columns (wind, lateral loads, etc) and also in the core columns. You could maybe expect further deformations of structure finding a new equilibrium and the tower may have tilted a little and stopped in that position but sudden global collapse is impossible due to the alleged load distribution!

Actually there is no evidence of any sort for the statement "Global collapse ensued". It is only wishful thinking by incompetent and/or complacent NIST engineers. They know that no steel skyscraper has ever collapsed due to fire!!

So what happened? Controlled demolition, CD, from top down? It seems that WCT 2 47 off core columns were damaged first, as the tower actually falls in its own footprint. The outer wall columns break afterwards like spaghetti by the floors being pulled down by the core columns. It seems that the core columns were broken by CD at every 10th floor, or so. NYFD staff noted these explosions, bang, bang, bang just before collapse ensued.

It would have been very easy to recover all the bits of the core columns from the rubble and assemble them on a 400 meter long field to verify (a) in how many parts each column split during collapse and (b) how the surface of the broken areas looked like. CD would probably have cut of the core columns sideways to dislocate them so that they could just drop down pulling other structure with them. Alternatively complete pieces of core columns were blown away. In either case a forensic examination of the core columns would have explained the collapse. If the collapse was due to release of potential energy overstraining the core pillars, the broken areas would look completely different. But as no complete forensic examinations were done for unknown reasons we must find other means to establish the real cause of the collapse. Easiest is of course a complete re-hearing of the case by a competent law court.

[uk_dave]

Floor trusses.

[Alferd_Packer]

I am a structural engineer specialized in shipbuilding. I have inspected many ships built of steel damaged by fire and overload of various kinds. None of these ships or their structures has ever collapsed by fire.

Correct me if I am wrong, but isn't the correct but isn't the correct term here "sank?"

Are you saying that no steel ship has ever sank due to fire?

[Alferd_Packer]

Heiwa, hypotheticly, what would happen to the critical buckling load of an exterior column if two adjacent floors start to sag?

In other words, if the sagging floors are no longer pinning the columns laterally, the effective length of the column will increase by a factor of 3.

What is the new value of the critical buckling load of the resulting three story column expressed as a percentage of the original resistance to buckling?

What would the percentage be if 4 adjacent floors sag or become disconnected?

[Heiwa]

Correct me if I am wrong, but isn't the correct but isn't the correct term here "sank?"

Are you saying that no steel ship has ever sank due to fire?

How could I have inspected them if they sank? One was on fire for five days in port. Didn't sink. But plenty of deformations of steel structure - but no collapses!

[grmcdorman]

Besides, aren't ships a wee bit different in construction than skyscrapers?

I'd like to see how well even WTC 7 would float.

[Heiwa]

Heiwa, hypotheticly, what would happen to the critical buckling load of an exterior column if two adjacent floors start to sag?

In other words, if the sagging floors are no longer pinning the columns laterally, the effective length of the column will increase by a factor of 3.

What is the new value of the critical buckling load of the resulting three story column expressed as a percentage of the original resistance to buckling?

What would the percentage be if 4 adjacent floors sag or become disconnected?

It is OT. I am only discussing load redistribution. And to keep it simple the structure consisted of only five structural column members - one core (subject to heat) and four outer walls (cooled by fresh air) - albeit kept together by floors. But I doubt very much that the floors sagged due to heat. Wishful thinking. I think most heat was vented away with the smoke and cooled by fresh air sucked in through all open windows.
It is a pity the core columns were not examined after the collapse.

[Alferd_Packer]

How could I have inspected them if they sank? One was on fire for five days in port. Didn't sink. But plenty of deformations of steel structure - but no collapses!


So then you freely admit that your experience in this matter is heavily biased toward structures that did not fail, since it is probable that a ship fire where the structure DID fail would result in the ship’s sinking.

[Heiwa]

Besides, aren't ships a wee bit different in construction than skyscrapers?

I'd like to see how well even WTC 7 would float.

Of course - but the structural analysis is the same.

[Alferd_Packer]

oops double post

[nicepants]

Of course - but the structural analysis is the same.

How many of these ships were hit by 767s at 500 mph?

[Heiwa]

So then you freely admit that your experience in this matter is heavily biased toward structures that did not fail, since it is probable that a ship fire where the structure DID fail would result in the ship’s sinking.

BTW, care to take a shot at answering my questions?

Of course I have also seen (ship) steel structures that failed due to overload, fatigue, corrosion, incorrect design, welding, faulty material, etc. My job is to find out why! The NIST reports are rubbish in this respect.

Better you answer your OT questions yourself. I do not see them relevant.

[Heiwa]

How many of these ships were hit by 767s at 500 mph?

None - but one was hit by an Exocet missile. Big hole + fire - but no collapse.

[uk_dave]

It is OT. I am only discussing load redistribution. And to keep it simple the structure consisted of only five structural column members - one core (subject to heat) and four outer walls (cooled by fresh air) - albeit kept together by floors. But I doubt very much that the floors sagged due to heat. Wishful thinking. I think most heat was vented away with the smoke and cooled by fresh air sucked in through all open windows.
It is a pity the core columns were not examined after the collapse.

Ahhhhhhh, nice to see you acknowledge the existence and purpose of the floors.

Pity you've never seen the pics of the sagging floor trusses though. Oh well, ignorance is bliss for some people.

[Alferd_Packer]

It is OT. I am only discussing load redistribution.

No, my questions were entirely pertinent to the topic.

You are talking about load redistribution without taking into account any possible changes to the load bearing abilities of the structural members.

Now answer my question: by what percentage of the original value will the critical buckling load of the column be reduced if two floors begin to sag?

What if three floors begin to sag?

[Tbone]

None - but one was hit by an Exocet missile. Big hole + fire - but no collapse.

So, despite completely different initiating events and construction and quite possibly materials, you feel that analysis on ship hulls and superstructures hit by missiles (if this is only one example, what were the others?) equates to analysis on 110 story skyscrapers hit by commercial airliners going 500mph.

[Alferd_Packer]

None - but one was hit by an Exocet missile. Big hole + fire - but no collapse.



And what particular ship was this, and under what capacity were you able to access it?

[uk_dave]

Tell you what Heiwa, since you're so much better informed and.... well, just so much more clever than those whacky guys at NIST, why don't you write a technical paper setting out your arguments (try not to put 'I think' in there too many times though) and then send it out to every Structural Engineering Journal and society in the world (email is a wonderful thing).

I assume that you also belong to a professional association, so no doubt they would be very interested in what one of their members has to say about one of the most traumatic events of the last 50 years.

You gonna do it?

[Heiwa]

So, despite completely different initiating events and construction and quite possibly materials, you feel that analysis on ship hulls and superstructures hit by missiles (if this is only one example, what were the others?) equates to analysis on 110 story skyscrapers hit by commercial airliners going 500mph.

Yes! The subject is what the NIST-engineers say. There is load redistribution ... and global collapse ensues. To me there is something missing between the two suggestions.

[Heiwa]

Tell you what Heiwa, since you're so much better informed and.... well, just so much more clever than those whacky guys at NIST, why don't you write a technical paper setting out your arguments (try not to put 'I think' in there too many times though) and then send it out to every Structural Engineering Journal and society in the world (email is a wonderful thing).

I assume that you also belong to a professional association, so no doubt they would be very interested in what one of their members has to say about one of the most traumatic events of the last 50 years.

You gonna do it?

At present we are just discussing some observations and missing links of the NIST report. Hopefully others will get the message?

[Alferd_Packer]

Yes! The subject is what the NIST-engineers say. There is load redistribution ... and global collapse ensues. To me there is something missing between the two suggestions.

Do you mean like a change in the load bearing capacity of the structural members?

by what percentage of the original value will the critical buckling load of a column be reduced if two floors begin to sag?

What if three floors begin to sag?

[Alferd_Packer]

And what particular ship was this, and under what capacity were you able to access it?



And don't forget to fill us all in on this unique expereince of yours.

[Heiwa]

And what particular ship was this, and under what capacity were you able to access it?

OT of course.

[Alferd_Packer]

Can I be the first to call you a B.S. artist?

[uk_dave]

At present we are just discussing some observations and missing links of the NIST report. Hopefully others will get the message?

What?

I thought you was 100% certain that the NIST explanation for the collapse was wrong.

Isn't that certainty enough for you to contact those professional bodies direct? Good grief, call yourself a professional? Get a grip.

Publish or be damned.

[Heiwa]

Do you mean like a change in the load bearing capacity of the structural members?

by what percentage of the original value will the critical buckling load of a column be reduced if two floors begin to sag?

What if three floors begin to sag?

According to NIST no floors start to sag when the load redistribution occurs. NIST claims that only load redistribution on the columns - without any calculations - caused global collapse. I show that the load distribution is minimal - 6.25% of the mass above is shifted to and is carried by intact columns and that it cannot cause global collapse.

WTC2 is not a house of cards (where a very small load redistribution causes global collapse at acceleration = gravity)!

[Heiwa]

Can I be the first to call you a B.S. artist?

Feel free if you feel better. The subject is the NIST allegations load re-distribution = global collapse.

[Alferd_Packer]

According to NIST no floors start to sag when the load redistribution occurs. NIST claims that only load redistribution on the columns - without any calculations - caused global collapse. I show that the load distribution is minimal - 6.25% of the mass above is shifted to and is carried by intact columns and that it cannot cause global collapse.

WTC2 is not a house of cards (where a very small load redistribution causes global collapse at acceleration = gravity)!

You are avoiding answering my questions. Why?

By what percentage of the original value will the critical buckling load of a column be reduced if two floors begin to sag?

What if three floors begin to sag?

[Heiwa]

What?

I thought you was 100% certain that the NIST explanation for the collapse was wrong.

Isn't that certainty enough for you to contact those professional bodies direct? Good grief, call yourself a professional? Get a grip.

Publish or be damned.

It has already been done by others. Best is a complete re-hearing of the case in a law court. I am just adding some simple observations in this forum to enlight the uninformed.

[Heiwa]

[QUOTE=Alferd_Packer;2780018]You are avoiding answering my questions. Why?
QUOTE]

OT

[uk_dave]

It has already been done by others. Best is a complete re-hearing of the case in a law court. I am just adding some simple observations in this forum to enlight the uninformed.

And failing miserably.

NIST identifies the sagging of the floor trusses pulling external columns inwards as being the mechanism for collapse.

You can barely bring yourself to admit that the floors tied the internal and external columns together and stopped the columns moving out of upright.

This has been gone over time and time again. You bring nothing new to this forum. If you have the proof that the towers could not have collapsed due to impact damage and fire, then go present it in court or to a professional body.

Bye bye Heiwa

[Alferd_Packer]

None - but one was hit by an Exocet missile. Big hole + fire - but no collapse.

Since you are making this claim of real world experience to establish your "expertise" in the topic, I have to once again ask you to provide details regarding this experience.

Name of the ship?

Year that you inspected it?

Location of the ship when you inspected it?

Under what capacity was your inspection performed (i.e. what was your job title)?

[Alferd_Packer]

OT

No, it is entirely pertinent to the topic that you posted. Your inability to see that only reinforces the fact that you really have no idea what I am talking about.

Your kung fu is weak.

[juryjone]

Heiwa,

Congratulations! You've posted a mere 13 times and already you've resorted to teh troofer mantra - "I'm just asking questions". Also, you've shown that you won't answer any pertinent questions, but just declare them "off-topic".

Well done. You'll fit in well with the other CTers here.

[gumboot]

And he replies!

????? Any opinions??


Um...

As for your strong interest in a topic you can't even spell...

And then he follows it up immediately with:

After the plane strike the buildings were what's called a chaotic system.

Irony, oh how sweet thou art!

-Gumboot

[gumboot]

How could I have inspected them if they sank? One was on fire for five days in port. Didn't sink. But plenty of deformations of steel structure - but no collapses!

On October 25, 1944 the Casablanca-class Escort Carrier USS St Lo (CVE-63) was deliberately hit by an aircraft, and the ensuing fires caused the ship to sink.

-Gumboot

[gumboot]

And to keep it simple the structure consisted of only five structural column members - one core (subject to heat) and four outer walls (cooled by fresh air) - albeit kept together by floors. But I doubt very much that the floors sagged due to heat. Wishful thinking. I think most heat was vented away with the smoke and cooled by fresh air sucked in through all open windows.
It is a pity the core columns were not examined after the collapse.



Are you honestly an engineer? Because with the above comments I don't believe you.

The floors did sag. There are plenty of photographs in the NIST report in which they can clearly be seen sagging. I can also cite other building fires in which floors (with much larger steel components) also sagged.

The heat on the exterior columns is irrelevant, because the exterior column failure was caused mechanically, not through heat. Again, there is ample documented evidence of the exterior wall bowing inwards.

Finally, upon initial wall failure the building twisted. A twist of the building any more than a couple of inches would pull every single support column off alignment, thus meaning there was nothing holding the upper structure.

Finally, can you, or can you not appreciate how a fire in a ship and a fire in a badly damaged 110 storey skyscraper are entirely unrelated, and in no way whatsoever comparable?

If you cannot appreciate this, you are not a structural engineer.

-Gumboot

[BillyRayValentine]

Of course - but the structural analysis is the same.

The structural analysis of a ship is the same as for a 110 story building?

Well done. Any other gems?

[R.Mackey]

I am a structural engineer specialized in shipbuilding. I have inspected many ships built of steel damaged by fire and overload of various kinds. None of these ships or their structures has ever collapsed by fire. Deformed, yes.


If you claim to be a naval engineer, then perhaps you're more comfortable with the Mumbai High North (http://www.mace.manchester.ac.uk/project/research/structures/strucfire/CaseStudy/HistoricFires/Other/default.htm) oil platform disaster -- ship collision leads to fire, fire leads to complete collapse of the steel platform. Did you conveniently forget about this, or is your appeal to authority a simple bluff?

As for ordinary ships, I cannot see how the loading of a ship's superstructure is in any way analogous to the construction of the WTC Towers, possibly excepting the IJN Fuso Class (http://en.wikipedia.org/wiki/Fuso_class) battleships.

According to NIST no floors start to sag when the load redistribution occurs. NIST claims that only load redistribution on the columns - without any calculations - caused global collapse. I show that the load distribution is minimal - 6.25% of the mass above is shifted to and is carried by intact columns and that it cannot cause global collapse.

WTC2 is not a house of cards (where a very small load redistribution causes global collapse at acceleration = gravity)!

NIST, of course, says nothing of the sort. In addition to load redistribution, you have weakening from heat, and you have buckling brought on by eccentric loading, viz. the floor trusses. Calculations are legion. I heartily recommend you actually read the NIST report before criticizing it.

Welcome to the Forum.

[LashL]

And what particular ship was this, and under what capacity were you able to access it?

Prediction: he or she will never answer this question.

Tell you what Heiwa, since you're so much better informed and.... well, just so much more clever than those whacky guys at NIST, why don't you write a technical paper setting out your arguments (try not to put 'I think' in there too many times though) and then send it out to every Structural Engineering Journal and society in the world (email is a wonderful thing).

I assume that you also belong to a professional association, so no doubt they would be very interested in what one of their members has to say about one of the most traumatic events of the last 50 years.

You gonna do it?

Prediction: he or she will not write any such paper, will not provide evidence of his/her alleged credentials, and will not set out his/her conspiratorial views to his/her alleged professional association to seek input.

And don't forget to fill us all in on this unique expereince of yours.

Prediction: he/she will not do so.

Now, I'm off to write up my application for the million dollar challenge... ;)

Oh, wait. No clairvoyance or supernatural or pyschic ability was required to predict a tinhatter's failure to provide any facts or evidence in support of a tinhatter's unfounded assertions... damn.

[stateofgrace]

I am a structural engineer specialized in shipbuilding. I have inspected many ships built of steel damaged by fire and overload of various kinds. None of these ships or their structures has ever collapsed by fire. Deformed, yes. I have some observations regarding the WTC2 collapse that may be of interest:


Really ?

Well I guess we work in the same industry. I really am an offshore engineer. I really do work on steel platforms and I really do know the dangers that comes with fires offshore. It as alrerady been pointed the dangers of fires offshore, but I guess you being a structural engineer who specialized in shipbuilding would know all about this wouldn't you ?

Ever heard of Piper Alpha ? Gee that collpased after explosions and fires also. As you know it laid down a whole host of offshore safety features, but then again I guess you know all about them don't you ?

In fact my new found friend I am actually on a ship, that you probably designed, working offshore right now, so hey I guess we have quite a bit in common don't we?You being an structural engineer will be able to tell me all about safety on this vessel won't you ?

Welcome to JREF.

[Heiwa]

Are you honestly an engineer? Because with the above comments I don't believe you.

The floors did sag. There are plenty of photographs in the NIST report in which they can clearly be seen sagging. I can also cite other building fires in which floors (with much larger steel components) also sagged.

The heat on the exterior columns is irrelevant, because the exterior column failure was caused mechanically, not through heat. Again, there is ample documented evidence of the exterior wall bowing inwards.

Finally, upon initial wall failure the building twisted. A twist of the building any more than a couple of inches would pull every single support column off alignment, thus meaning there was nothing holding the upper structure.

Finally, can you, or can you not appreciate how a fire in a ship and a fire in a badly damaged 110 storey skyscraper are entirely unrelated, and in no way whatsoever comparable?

If you cannot appreciate this, you are not a structural engineer.

-Gumboot

It would appear that some floors sagged on the WCT2 east wall due to the initial impact and that then no more floors sagged. And the tower was standing. There is no evidence that the floors later started to sag or became disconnected from the columns due to heat. This is just an invention of NIST without evidence.

The floor connections to the outer columns can be seen intact on the south wall around the hole, the north wall and the west wall. Most windows were broken so the heat could easily escape with the smoke.

The floor connections to the core columns are not known but the core columns were supported by floors all round except at lift trunks and stairways, but there the columns were interconnected by vertical supports, etc. so I do not believe that the floors sagged in the core.

And of course - even a sagged floor provides support as long as it is connected to the columns.

The floors, BTW, were not subject to much load! What does NIST say - 20 kgs/m² of furniture. So the floors could only sag due to its own weight and it can never pull apart the connections to the columns.

I agree that the floors on the east wall were disconnected due to the initial impact and that the east wall apparently buckled inward due to that and that then load re-distribution occurred as I (but not NIST) have explained. But it would not cause global collapse. The load on the intact columns are just increased marginally!

It is a pity that the forensic examination of the core columns was so sloppy = non-existing.

[Heiwa]

Really ?

Well I guess we work in the same industry. I really am an offshore engineer. I really do work on steel platforms and I really do know the dangers that comes with fires offshore. It as alrerady been pointed the dangers of fires offshore, but I guess you being a structural engineer who specialized in shipbuilding would know all about this wouldn't you ?

Ever heard of Piper Alpha ? Gee that collpased after explosions and fires also. As you know it laid down a whole host of offshore safety features, but then again I guess you know all about them don't you ?

In fact my new found friend I am actually on a ship, that you probably designed, working offshore right now, so hey I guess we have quite a bit in common don't we?You being an structural engineer will be able to tell me all about safety on this vessel won't you ?

Welcome to JREF.

You are right! I am now working in the offshore industry looking after structural maintenance of various units ... and also the initial designs where mistakes may occur, e.g. to enable people to later inspect all areas. I am quite good at spotting fractures in the structures and then to analyse them and the risks involved.

[Heiwa]

The structural analysis of a ship is the same as for a 110 story building?

Well done. Any other gems?

Of course the structural analysis of intact and damaged structure is the same but more complex for ships and offshore units that are subject to more complex loadings. The WCT2 structure is quite simple with vertical columns and horizontal trusses (and floors) and quite good connections between them and plenty of redundancy. WCT2 was just loaded by static gravity forces (own weight + furniture) and lateral wind forces (and maybe forces due to earth quakes?). Easy to analyse. Also the damaged structure is easy to analyse ... if you know what is damaged and how but unfortunatley no detailed forensic analysis was done.

To assume that all 600 + truss/floors connections to the columns suddenly burst due to heat (and load re-distribution?) in the damaged area is preposterous as the load on the trusses/floors was minimal and could not rip apart the connections, even if heated. But the outer walls were not particularly heated as they were cooled by the brisk breeze blowing outside.

And what was the temperature inside? It appears NYFD staff arrived to damaged floors through the core area and reported some minor, isolated fires, easy to handle.

They thus walked on the floors/trusses in the core area and observed no sagging there ... and that evidently the core columns were intact. I like that.

What disturbes me is the sudden collapse of the core. In my view it could only have been caused by controlled demolition.

[LashL]

Oh, look. Yet another twoofer who has made unsubstantiated claims fails to address the points raised and instead goes off on twoofer tangents.

Colour me surprised. :rolleyes:

[gumboot]

It would appear that some floors sagged on the WCT2 east wall due to the initial impact and that then no more floors sagged. And the tower was standing. There is no evidence that the floors later started to sag or became disconnected from the columns due to heat. This is just an invention of NIST without evidence.



Okay, first off... the NIST collapse theory quite clearly states, and indeed relies on, NO floor trusses becoming disconnected from the columns. Had that happened, collapse could not have happened.

Secondly, the photographic evidence of floor truss sagging - which included all floors in the impact zone - was not visible immediately after the impact, and the degree of sagging increasing over time - directly proportional to the degree of bowing in the exterior columns.




The floor connections to the outer columns can be seen intact on the south wall around the hole, the north wall and the west wall. Most windows were broken so the heat could easily escape with the smoke.


The NIST collapse theory requires that the floor trusses remained attached to the exterior columns until the point of collapse initiation. The above comment makes me think you haven't actually read the NIST report at all. And the comment about heat is just stupid.





The floor connections to the core columns are not known but the core columns were supported by floors all round except at lift trunks and stairways, but there the columns were interconnected by vertical supports, etc. so I do not believe that the floors sagged in the core.

And of course - even a sagged floor provides support as long as it is connected to the columns.


I don't think you understand the significance of the sagging floors at all.





The floors, BTW, were not subject to much load! What does NIST say - 20 kgs/m² of furniture. So the floors could only sag due to its own weight and it can never pull apart the connections to the columns.

I agree that the floors on the east wall were disconnected due to the initial impact and that the east wall apparently buckled inward due to that and that then load re-distribution occurred as I (but not NIST) have explained. But it would not cause global collapse. The load on the intact columns are just increased marginally!

It is a pity that the forensic examination of the core columns was so sloppy = non-existing.


It's a pity your understanding of NIST's explanation for the collapse is so sloppy - non-existing. In the preceding two paragraphs you make countless mistakes.

-Gumboot

[gumboot]

To assume that all 600 + truss/floors connections to the columns suddenly burst due to heat (and load re-distribution?) in the damaged area is preposterous as the load on the trusses/floors was minimal and could not rip apart the connections, even if heated. But the outer walls were not particularly heated as they were cooled by the brisk breeze blowing outside.


You don't know anything about fires do you?

If you take a small fire and blow on it does the fire get hotter or colder?

As for the 600 connections? As you should know, had you read the NIST report, these connections did not fail. Try again.




And what was the temperature inside? It appears NYFD staff arrived to damaged floors through the core area and reported some minor, isolated fires, easy to handle.


Hah. Look, a CTer regurgitating the same old BS again.




They thus walked on the floors/trusses in the core area and observed no sagging there ... and that evidently the core columns were intact. I like that.


On the 78th floor in WTC2. Which was the closest any FDNY personnel got to the impact zone. The fires on the 78th floor of WTC2, according to NIST, were pretty minor. This probably had something to do with it being the lowest impact floor, being a Sky Lobby (no office furniture to burn) not being doused in jet fuel (only the end of the port wing of UA175 hit the 78th floor, and the tip of the wings have no fuel in them), a the fact that heat travels upwards.





What disturbes me is the sudden collapse of the core. In my view it could only have been caused by controlled demolition.


You mean the sudden collapse that occurred after the rest of the building had collapsed? you mean that "sudden" collapse of the core? :rolleyes:

-Gumboot

[uk_dave]

Okay, first off... the NIST collapse theory quite clearly states, and indeed relies on, NO floor trusses becoming disconnected from the columns. Had that happened, collapse could not have happened.



Can we really say this with certainty?

The floor trusses played a pivotal role in the stability of the towers. Had a floor assembly let go of the external columns and crashed down on to the floor below, overloading that which in turn failed at the connections with the columns, then we could have seen a progressive collapse down to the ground.

It would be the continuing vertical loading on the now unrestrained columns which would cause them to move out of upright and ultimately come apart as gravity pulled them downwards.

ETA: Rather as breifly witnessed with the remains of the unrestrained core columns at the end of the main collapse

[stateofgrace]

You are right! I am now working in the offshore industry looking after structural maintenance of various units ... and also the initial designs where mistakes may occur, e.g. to enable people to later inspect all areas. I am quite good at spotting fractures in the structures and then to analyse them and the risks involved.
Is that a fact ?

yet you labour under the impression that offshore installations do not collapse due to fire. See this is the issue I have with you, you claim to be a structural engineer who is all clued in about structural failures offshore yet you have not learnt a thing from the collapse of the WTCs.

I like to think that when some guy is making safety recommendations offshore that directly effect me and my colleges, that they actually understand what they are talking about. I like to think that they know and understand that steel structures do collapse when there is enough heat, oxygen and fuel. I think to think that they fully understand that the single biggest danger offshore is fire and that they don't dismiss it as a nuisance that mearly warps structures.

I also like to think that a structural engineer who is responsible for the maintained of offshore structures, which is actually not what you claimed first, you claimed you were a structural engineer who worked on ship design knows what he is about. So which offshore structures are you actually responsible for? I am curious as to exactly what you do offshore and exactly what your position is. hey maybe we could hook and talk about various offshore projects we have worked on , Thunderhorse maybe ? How about Spiderman ? I take you have been out here a while to hold such a prestigious position, after somebody who is responsible for the structural integrity of offshore installations is hardy a novice are they ?

[Alferd_Packer]

Heiwa, The grass grows green around your feet

(i.e. you are a lying sack of biosolids.)

You lie so much, you have to get someone else to call your dog for you.

[gumboot]

Can we really say this with certainty?

The floor trusses played a pivotal role in the stability of the towers. Had a floor assembly let go of the external columns and crashed down on to the floor below, overloading that which in turn failed at the connections with the columns, then we could have seen a progressive collapse down to the ground.

It would be the continuing vertical loading on the now unrestrained columns which would cause them to move out of upright and ultimately come apart as gravity pulled them downwards.

ETA: Rather as breifly witnessed with the remains of the unrestrained core columns at the end of the main collapse



Sorry, yeah... it couldn't have happened the way it did. Which is a bit redundant I suppose.

Although I think, had a single floor truss broken away, there's probably a feasible chance the lower trusses would have arrested it. Bear in mind people trapped in the building made numerous reports of upper floors collapsing and partially collapsing well before the exterior columns failed.

So it seems at least reasonable to me that a floor truss failure alone would not have progressed very far.

And as our new friend points out, in a floor truss failure scenario it's unlikely the entire thing would drop away at once, as it was made up of sections. More likely sections would break away on their own, and just collapse onto the floor below.

-Gumboot

[Heiwa]

Is that a fact ?

yet you labour under the impression that offshore installations do not collapse due to fire. See this is the issue I have with you, you claim to be a structural engineer who is all clued in about structural failures offshore yet you have not learnt a thing from the collapse of the WTCs.

I like to think that when some guy is making safety recommendations offshore that directly effect me and my colleges, that they actually understand what they are talking about. I like to think that they know and understand that steel structures do collapse when there is enough heat, oxygen and fuel. I think to think that they fully understand that the single biggest danger offshore is fire and that they don't dismiss it as a nuisance that mearly warps structures.

I also like to think that a structural engineer who is responsible for the maintained of offshore structures, which is actually not what you claimed first, you claimed you were a structural engineer who worked on ship design knows what he is about. So which offshore structures are you actually responsible for? I am curious as to exactly what you do offshore and exactly what your position is. hey maybe we could hook and talk about various offshore projects we have worked on , Thunderhorse maybe ? How about Spiderman ? I take you have been out here a while to hold such a prestigious position, after somebody who is responsible for the structural integrity of offshore installations is hardy a novice are they ?

"The James Randi Educational Foundation is a not-for-profit organization founded in 1996. Its aim is to promote critical thinking by reaching out to the public and media with reliable information about the paranormal and supernatural ideas that are so widespread in our society today."

Offshore structures are generally welded together at very high temperatures/melting the adajcent parts under very controlled conditions and will not collapse due to fire or heat from a fire. Reason is that the welded connections will not be ripped apart due to fire. Structural parts, eg trusses or colums, between welded connections may deform due to fire/heat and loads on top but deformation will just lead to new equilibriums - never sudden collapse. Same for WTC2 albeit some connections were not welded but bolted or rivetted together. Some connections between floors/columns were aparently damaged after the initial explosion in WTC2 but afterwards heat could never have dislodged the floors/trusses from the columns. Everything would be kept together - albeit deformed or sagged - preventing sudden collapse. Strutural collapse is not a risk when fires occur and that is why no steel scyscraper or offshore installation for that matter has ever totally collapsed due fire/heat. Except WTC1,2 and 7.

That WTC2 collapsed due to - small - re-distribution of loads is thus a paranormal and supernatural idea ... that we try to discuss. Unfortunately many participants get upset and make personal attacks on the messenger, totally OT. Lack of critical thinking? Or blinded by 1000's of pages of NIST reports about the original design, the fires ranging, etc. and only 1/2 page that I quoted in my first message that due some local deformation of an eastern wall and load re-distribution (cause), global collapse of the complete building ensues (effect).
And no forensic evidence to back up this illogical and supernatural cause/effect allegation!
I understand that millions of Americans are wondering about it.

[maccy]

Offshore structures are generally welded together at very high temperatures/melting the adajcent parts under very controlled conditions and will not collapse due to fire or heat from a fire. Reason is that the welded connections will not be ripped apart due to fire. Structural parts, eg trusses or colums, between welded connections may deform due to fire/heat and loads on top but deformation will just lead to new equilibriums - never sudden collapse. Same for WTC2 albeit some connections were not welded but bolted or rivetted together. Some connections between floors/columns were aparently damaged after the initial explosion in WTC2 but afterwards heat could never have dislodged the floors/trusses from the columns. Everything would be kept together - albeit deformed or sagged - preventing sudden collapse. Strutural collapse is not a risk when fires occur and that is why no steel scyscraper or offshore installation for that matter has ever totally collapsed due fire/heat. Except WTC1,2 and 7.

http://en.wikipedia.org/wiki/Piper_Alpha

If you're interested in the truth, why are you lying?

ETA:
http://home.versatel.nl/the_sims/rig/adriatic4.htm
http://home.versatel.nl/the_sims/rig/enchova.htm

[Alferd_Packer]

Let me try this again.

Let’s deal with this as a purely hypothetical scenario.

you have a multi story building with a floor to ceiling height of 13 feet. The floor slabs act to pin the exterior columns in place. The critical buckling load of a single floor to ceiling span of exterior column is given as X. If two adjacent floors begin to sag, or become disconnected so that they no longer serve to pin the column in place, what will be the critical buckling load for the resulting three story, un-pinned, column span?

Are there any shipbuilding, structural engineers out there that can answer my question?

Any trwooothers at all that can answer my question?

[BillyRayValentine]

Of course the structural analysis of intact and damaged structure is the same...

As would be the structural analysis of a tool shed, apparently.

You are most definitely not a structural engineer. Not even close.

To assume that all 600 + truss/floors connections to the columns suddenly burst due to heat (and load re-distribution?) in the damaged area is preposterous as the load on the trusses/floors was minimal and could not rip apart the connections, even if heated. But the outer walls were not particularly heated as they were cooled by the brisk breeze blowing outside.

And what was the temperature inside? It appears NYFD staff arrived to damaged floors through the core area and reported some minor, isolated fires, easy to handle.

They thus walked on the floors/trusses in the core area and observed no sagging there ... and that evidently the core columns were intact. I like that.

What disturbes me is the sudden collapse of the core. In my view it could only have been caused by controlled demolition.

You have a completely botched understanding of the NIST report. And your comments about minor fires and cooling breezes are mind-numbingly stupid.

Shoo.

[Belz...]

It would appear that some floors sagged on the WCT2 east wall due to the initial impact and that then no more floors sagged.

Sagging due to impact ? Not heat ?

And the tower was standing.

Not for long, it wasn't.

There is no evidence that the floors later started to sag or became disconnected from the columns due to heat.

Who said anything about disconnecting ? The floors sagged and PULLED on the perimeter columns. There's plenty of pictures and videos where this is evident.

And of course - even a sagged floor provides support as long as it is connected to the columns.

Not if it breaks the columns in the process.

The floors, BTW, were not subject to much load!

Doesn't matter. THEY were doing the pulling.

It is a pity that the forensic examination of the core columns was so sloppy = non-existing.

Right.

To assume that all 600 + truss/floors connections to the columns suddenly burst due to heat (and load re-distribution?) in the damaged area is preposterous

Who said anything about "suddenly".

What disturbes me is the sudden collapse of the core. In my view it could only have been caused by controlled demolition.

Sudden ? It collapsed AFTER the building came down. AFTER. How is that "sudden" ?

[stateofgrace]

Offshore structures are generally welded together at very high temperatures/melting the adajcent parts under very controlled conditions and will not collapse due to fire or heat from a fire. Reason is that the welded connections will not be ripped apart due to fire.

Really?

You have claimed to be an offshore structural engineer, you have claimed to be in charge of offshore structures, you have claimed that fires will not collapse offshore steel structures.

I have trainees working under me, one has been offshore for less than a week and he knows more about the dangers of fires out here than you do. Tell me , is it now safe to start smoking in the exclusions zones? I take it you do know what the exclusion zone is,do you ? Every man and his dog knows about it, it is drilled into every single offshore worker, what do you understand it to be ?

[Gravy]

So now there are two offshore drilling rig engineers who are 9/11 deniers and who know diddley-squat about the towers?

Or is this new one Charles Pegelow (I haven't read the whole thread)?

Either way, just pathetic.

Edit: after reading a few of his posts, it seems that Heiwa thinks that NIST subscribes to the pancake theory of collapse initiation. Heiwa, if this is so, you really have a lot of reading to do.

Also, you should really read this page:
Accounts of structural instability in the Twin Towers, Bowing of columns, Collapse expected (http://911stories.googlepages.com/accountsoftowerstructuralinstabilityande)

Finally, in case no one has informed you, the controlled demoliton theory is suitable only for incompetents, liars, and idiots.

[Alferd_Packer]

Hey, Heiwa, or can I call you Chuck? Are you still working for Fulton?

Give it up, you aren’t impressing anyone here.


edit, damnit Gravy, you beat me to it.

[Panoply_Prefect]

So now there are two offshore drilling rig engineers who are 9/11 deniers and who know diddley-squat about the towers?

Or is this new one Charles Pegelow (I haven't read the whole thread)?


Hey, Heiwa, or can I call you Chuck? Are you still working for Fulton?

Give it up, you aren’t impressing anyone here.


edit, damnit Gravy, you beat me to it.

Heiwa's homepage can be found here:

http://heiwaco.tripod.com/

and his CV is here:

http://heiwaco.tripod.com/cv.htm


He subscribes not only to the "North of Citgo"-theory of Merc and Lyte, but also the "No plane hit the Twin Towers" as proposed by in the videoanalyses of "Socialworker".

Just to get a tad of background. But yes, as far as I can tell he actually is a Naval Architect and Marine Engineer.

Oh, and welcome Heiwa - now I dont have to ask you to translate your calculations anymore, you can just post them yourself!

Cheers,
SLOB

[Heiwa]

Who said anything about disconnecting ? The floors sagged and PULLED on the perimeter columns. There's plenty of pictures and videos where this is evident.



Aha - the floors sagged (due to heat) and pulled the perimeter columns inward. But it is not possible! There is no weight on the floor except it own weight and 20 kgs/m² of furniture, etc above.

No, the sagging floor cannot pull the perimeter columns inward. Only where one floor was disconnected (by the explosion) on the east wall, the floor sagged a little and the perimeter columns deformed inwards ... and rested then against the floor. It was a stable condition.

But these are minor details. The big question is why the NIST engineers, after writing 1000+ pages of the intact structure and the fires seen in various locations, just concluded what they wrote on one page ... as quoted previously but I repeat:

"Buckling of East Wall and Collapse Initiation

With continuously increased (sic) bowing and axial loads, the entire width of the east wall buckled inward. The instability started at the center of the wall and rapidly (sic) progressed horizontally towards the sides. As a result of the buckling of the east wall, the east wall significantly unloaded, redistributing its load to the softened core through the hat truss and to the south and north walls through the spandrels ( …). The section of the tower above the buckled wall suddenly moved downward, and the building tilted to the east ( …).

The section of the building above the impact zone tilted to the east and south (observed at about 7° to 8° to east and about 3° to 4° to south, …) as column instability progressed from the east wall to the adjacent south and north walls. The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued (sic)."

Actually, we only see the deformed east wall - no buckled, only deformed columns - on some photos/videos but not the rest. Rapid (? - when) progressive deformation of the east wall sideways?? No evidence at all. And collapse of the perimeter columns of the north and south walls as a consequence and load re-distrbution? No evidence. And it is not even possible. The redistribution of load is too small and it should take much longer time if it was possible! The suggestions are inventions. But why do the NIST engineers invent them?

Probably because they were very afraid of stating what we all see on the videos; that all the 47 core columns - occupying or rather supporting 50% of the tower - are giving way simultaneously prior to anything happening at the east wall, and they cannot explain that ... or would not admit that it is only possible by controlled demolition.

Easier to invent something. Like the battered wife that will not report the person beating her - the husband. She just walked into a door and the east wall fell down ... and the complete house with it. Both agree. And the neighbours.

Heiwa

PS Please avoid personal insults when answering as they just upset you and damage your health or what is left of it. Calm down!:) :)

[Gravy]

Of course - but the structural analysis is the same.Argument from personal incredulity is not structural analysis, Heiwa.

[Heiwa]

Heiwa's homepage can be found here:

http://heiwaco.tripod.com/

and his CV is here:

http://heiwaco.tripod.com/cv.htm


He subscribes not only to the "North of Citgo"-theory of Merc and Lyte, but also the "No plane hit the Twin Towers" as proposed by in the videoanalyses of "Socialworker".

Just to get a tad of background. But yes, as far as I can tell he actually is a Naval Architect and Marine Engineer.

Oh, and welcome Heiwa - now I dont have to ask you to translate your calculations anymore, you can just post them yourself!

Cheers,
SLOB

SLOB is slightly wrong - referring to different theories in a discussion (sic - is it?) does not necessarily mean subscribing to them. It just shows there are differences of opinions. But subscribers to other theories seem to get upset and sick. I always wonder why.

Enjoy my home page. If you find any errors there, pls send me a (polite) line and I will correct.

[Gravy]

Aha - the floors sagged (due to heat) and pulled the perimeter columns inward. See, you should have known NIST's conclusion, which is backed by a mountain of evidence, before you attempted to critique NIST's conclusion.

PS Please avoid personal insults when answering as they just upset you and damage your health or what is left of it. Calm down!:) :)It is you who needs to calm down and become informed about the subject you are attempting to argue.

If you want to study the problems and produce your own scholarly analysis, your work will be welcomed. If you can produce informed criticism of the NIST and other WTC engineering reports, and can back your statements with evidence, your work will be welcomed. Your arguments from incredulity are not welcome.

When an engineer disrespects and ignores professional standards, I will not be nice. Get used to it if you're going to continue posting in this fashion.

[Gravy]

SLOB is slightly wrong - referring to different theories in a discussion (sic - is it?) does not necessarily mean subscribing to them. It just shows there are differences of opinions. But subscribers to other theories seem to get upset and sick. I always wonder why.

Enjoy my home page. If you find any errors there, pls send me a (polite) line and I will correct.Do you believe that airliners hit the Twin Towers, the Pentagon, and a field in Pennsylvania on 9/11?

[ref]

Sigh, now we have this Estonia conspiracy guy here. Well, I guess everyone is welcome here.. so welcome.

[Alferd_Packer]

A hypothetical scenario

you have a multi story building with a floor to ceiling height of 4 meters. The floor slabs act to pin the exterior columns in place.

The critical buckling load of a single floor to ceiling span of exterior column is given as X.

If two adjacent floors begin to sag, or become disconnected so that they no longer serve to pin the column in place, what will be the critical buckling load (as a percentage of X) for the resulting three story, 12 meter, un-pinned, column span?

[Heiwa]

A hypothetical scenario

you have a multi story building with a floor to ceiling height of 4 meters. The floor slabs act to pin the exterior columns in place.

The critical buckling load of a single floor to ceiling span of exterior column is given as X.

If two adjacent floors begin to sag, or become disconnected so that they no longer serve to pin the column in place, what will be the critical buckling load (as a percentage of X) for the resulting three story, 12 meter, un-pinned, column span?

OT but an easy one answered by Euler already 1744. The critical load P is

P = pi² x E x I / L² where L is the unsupported length of the column.

So if P = 100% when L is one unit, it is 25% when L is two units, it is 11.11 % when L is three units, etc. This is basic! Didn't you know Euler?

[Belz...]

Aha - the floors sagged (due to heat) and pulled the perimeter columns inward. But it is not possible! There is no weight on the floor except it own weight and 20 kgs/m² of furniture, etc above.

So ? Do you have any idea how much fire weakens steel ?

No, the sagging floor cannot pull the perimeter columns inward. Only where one floor was disconnected (by the explosion) on the east wall, the floor sagged a little and the perimeter columns deformed inwards ... and rested then against the floor. It was a stable condition.

You're not very good at this.

The sagging was due to HEAT, not excess loads. The floors were NOT disconnected from the columns and that's the WHOLE point. Because they weren't, they pulled on the columns.

Actually, we only see the deformed east wall - no buckled, only deformed columns - on some photos/videos but not the rest.

You only need ONE wall to fail to initiate collapse. In fact, you can see the top section of 2 WTC tilt at the beginning. Then the strain snaps the remaining columns and the whole thing comes down. Dammit, man. You can see this on the videos quite clearly.

Rapid (? - when) progressive deformation of the east wall sideways?? No evidence at all.


http://forums.randi.org/imagehosting/thum_608045892c4f64e35.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3266)

And collapse of the perimeter columns of the north and south walls as a consequence and load re-distrbution? No evidence.

The theory explains what happened and is supported by VISUAL evidence. What do you need ? A signed document from the Maker confirming this ?

And it is not even possible. The redistribution of load is too small and it should take much longer time if it was possible!

Please tell us how much time it would take, and the exact percentage of redistribution...

The suggestions are inventions. But why do the NIST engineers invent them?

Begging the question.

Probably because they were very afraid of stating what we all see on the videos; that all the 47 core columns - occupying or rather supporting 50% of the tower - are giving way simultaneously prior to anything happening at the east wall, and they cannot explain that ... or would not admit that it is only possible by controlled demolition.

Again, please explain the following:

1) What kind of demolition charge produces no explosion and no sound ?
2) How can 47 columns fail simultaneously and STILL result in the top section tilting as it fell ?
3) How do you know the core failed first since we can clearly see it collapse LAST ?
4) What kind of explosive can caused the extreme bowing seen in this photograph ?

http://forums.randi.org/imagehosting/thum_608045892c65f25a4.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3267)

Easier to invent something.

Nonsense. Thousands of engineers and scientists around the world, with no affiliation to the US government, would be able to spot the discrepancies.

PS Please avoid personal insults when answering as they just upset you and damage your health or what is left of it. Calm down!:) :)

Toughen up.

[Heiwa]

Sigh, now we have this Estonia conspiracy guy here. Well, I guess everyone is welcome here.. so welcome.

Thanks - OT of course but I am not 'this Estonia conspiracy guy'. I just happened to assist operating 12 similar ferries 1994 and in order to avoid the fate of the Estonia (BTW for those of don't know - it was a ferry that sank mysteriously 1994 in the Baltic with at least 852 dead) to our own ferries, we decided look into the matter. And what did we find? Well, it is described on my homepage listed above, but to keep it short; the governments officials and 'experts' produced a report 1997 where every essential information and conclusion was false (!!) that I showed in a book published 1998. It got good reviews.

The governments were evidently not happy. One idiot went public and accused me to bring down his goverment! So instead of a polite exchange of opinions, the governments got angry and tried all sorts of tricks to destroy my reputation. Sad actually. I just laugh at those fools. What about the government 'experts'? They were forced to assist with the conspiracy. They were too afraid to do a proper job.

Sometimes I have a feeling the NIST engineers have fallen into the same trap. And this is the real subject of this discussion.

[Alferd_Packer]

OT but an easy one answered by Euler already 1744. The critical load P is

P = pi² x E x I / L² where L is the unsupported length of the column.

So if P = 100% when L is one unit, it is 25% when L is two units, it is 11.11 % when L is three units, etc. This is basic! Didn't you know Euler?

Well it took you long enough to google up the answer.

Now try this, How would the loss of the lateral support and the subsequent reduction in the critical buckling load affect the DCR of the columns?

[ref]

Thanks - OT of course but I am not 'this Estonia conspiracy guy'. I just happened to assist operating 12 similar ferries 1994 and in order to avoid the fate of the Estonia (BTW for those of don't know - it was a ferry that sank mysteriously 1994 in the Baltic with at least 852 dead) to our own ferries, we decided look into the matter. And what did we find? Well, it is described on my homepage listed above, but to keep it short; the governments officials and 'experts' produced a report 1997 where every essential information and conclusion was false (!!) that I showed in a book published 1998. It got good reviews.

The governments were evidently not happy. One idiot went public and accused me to bring down his goverment! So instead of a polite exchange of opinions, the governments got angry and tried all sorts of tricks to destroy my reputation. Sad actually. I just laugh at those fools. What about the government 'experts'? They were forced to assist with the conspiracy. They were too afraid to do a proper job.

Sometimes I have a feeling the NIST engineers have fallen into the same trap. And this is the real subject of this discussion.

I am Finnish, just to let you know, because I know you are Swedish. I'm familiar with Estonia, of course. Not so much with your theories. I have heard about you, though. But enough about that. Back to the topic folks.

[Heiwa]

So ? Do you have any idea how much fire weakens steel ?



You're not very good at this.

The sagging was due to HEAT, not excess loads. The floors were NOT disconnected from the columns and that's the WHOLE point. Because they weren't, they pulled on the columns.



You only need ONE wall to fail to initiate collapse. In fact, you can see the top section of 2 WTC tilt at the beginning. Then the strain snaps the remaining columns and the whole thing comes down. Dammit, man. You can see this on the videos quite clearly.




http://forums.randi.org/imagehosting/thum_608045892c4f64e35.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3266)



The theory explains what happened and is supported by VISUAL evidence. What do you need ? A signed document from the Maker confirming this ?



Please tell us how much time it would take, and the exact percentage of redistribution...



Begging the question.



Again, please explain the following:

1) What kind of demolition charge produces no explosion and no sound ?
2) How can 47 columns fail simultaneously and STILL result in the top section tilting as it fell ?
3) How do you know the core failed first since we can clearly see it collapse LAST ?
4) What kind of explosive can caused the extreme bowing seen in this photograph ?

http://forums.randi.org/imagehosting/thum_608045892c65f25a4.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3267)



Nonsense. Thousands of engineers and scientists around the world, with no affiliation to the US government, would be able to spot the discrepancies.



Toughen up.

I don't know how to quote above with sub-quotes but here we go.

There was no load on the floors above, except their own weight + furniture. Why concrete floors + steel trusses would then sag due to heat is beyond me but it will not be much. I know steel expands due to heat ... but concrete!! No way. The floors were >95% concrete. And that combination supported the perimeter columns regardless of any sagging.

Sorry - one (east) wall - supporting only 12.5% of the total load cannot initiate total global collapse. Why - the other structure, particularly the core, will easily support the load transferred to it. Basic. It is seen on the photos! The east wall is deformed ... and the other parts are intact. The tower stands.

And suddenly the whole thing explodes! But videos of the roof - far above - shows that it sags a little before that = the 47 core columns apparently failed before the east wall. Similar to WTC7? Strange case. But support for Controlled Demolition.

It would have been easy to check why the 47 off 400 metres tall core columns failed by proper forensic examination. But it was not done. This is why I suspect an Inside Job. And it is easiest decided by a re-hearing of the whole case in a law court. I actually believe in the Law of Justice. Do you?

[Panoply_Prefect]

Umm arent these supposed to be pictures of the sagging floors:

http://oceanmirage.homestead.com/files/Fig9_52.jpg

http://www.debunking911.com/sag.ht1.jpg

[DavidJames]

I actually believe in the Law of Justice. Do you?I believe in evidence and you've presented nothing but an argument from incredulity. Which means nothing to science, engineering and the court of law.

But please come back when you are able to present something tangible.

[uk_dave]

Good grief, it gets worse.

Let's try some imaginary scenarios:

First, let's say we have a beam that is spanning across a void 3.0m wide. For the sake of argument will say it is 152x152mm UB.

Now this beam is nice and flat and when we stand on it it doesn't move a millimetre. Lovely beam it is. We like this beam.

Now, we have an endless supply of beams like this, only in varying lengths. And because we like it so much, we decide to use a similar beam to span across a void 30 metres wide.

But this time we're not so happy. Can anyone tell me why?

..................

We've learned our lesson from the unhappy experience with the 30.0m beam and now we've got all clever and stuff and we've figured out how to span that distance using our favourite beams. We'll use two of them!! Aren't we clever?

Even clevererer we'll have one baem above the other and we'll connect them together with struts and braces until we have a very pretty beam indeed. We're feeling very good now.

We span our new sooper dooper beam across the void and it's solid and steady and ohhhh so fantastic, so it is.

But we really need to hold it in place with something because sometimes, when we've had a very very hot curry and we're standing on our beam, it starts to wobbly. oooooooo scarey.

So we get another couple of our most favourite beams and this time we put them upright. They look so good like that. We put one at each end of our sooper dooper beam and we fix it all together with magic fairy nuts.

ooooooooo we are soooooo clever. The most clererest thing in the whole whole..... but wait. What's this? An evil troll is in the void just under our lovely beam. And he's cooking his socks! What a smelly old troll he is. And what a big fire he has built. The flames are almost touching our beam.

But we're not scared are we boys and girls? Noooooooo. We can stand on the middle of our beam and blow rasberries at the smelly troll because he can't reach us.

But then we feel our beam begin to move. What's happening? Oh my, the fire is somehow making our beam go weak. But, not to worry, because it is safely fixed at both ends and can't fall on top of the smelly troll.

But wait...oh no!!! the eccentric forces applied to the upright members is causing them to rotate about their axis, and the fairy nuts aren't letting go!!

Help! Help! we cry, as our beam sags more and more and the fire starts to touch our toes and then, with a crack and a bang and a whoosh and a twang, our beam and our posts tumbles down into the trolls fire.

And we're sad, because the troll is now applying barbeque sauce to our nether regions.

Goodnight boys and girls.

[Newtons Bit]

There was no load on the floors above, except their own weight + furniture. Why concrete floors + steel trusses would then sag due to heat is beyond me but it will not be much. I know steel expands due to heat ... but concrete!! No way. The floors were >95% concrete. And that combination supported the perimeter columns regardless of any sagging.


Annnnnnnnd you just proved to me that you know nothing about structural engineering. Let's explain some concepts that you should have picked up in the second or third year of your undergraduate program:

The concrete slab in the WTC was composite with the floor trusses, which means that they acted together to resist bending moments. This translates to the concrete slab and the top chord of the truss being in compression, and the bottom chord of the truss in tension. Fairly basic concept for most people, you seem to be implying that the concrete did most of the work in holding the floors up.

The important point here, is how steel behaves when it is heating. You think that it only expands. Probably something you picked up watching a cooking show on TV. Something else important thing that changes is the modulus of elasticity. This modulus is the ratio of pressure to percent deformation. When the steel heats up, the modulus of elasticity goes down. So the bottom chord expierences higher amounts of elongation, hence sagging. This is immediately obvious to anyone who took a basic course in mechanics of materials, which you've either forgotten or never took.

There's something else that happens with the above, since the top chord is in compression and the bottom chord is tension, any increase in heat would result in strain compability issues with the web members. The web, being welded to the top and bottom chord of the truss, will be stretched as the bottom chord elongates and the top chord shrinks.

The above is probably the first explanation most engineers would come to when looking at a bending member that sagged due to heat. However it is not the only one.

The second one that comes to mind is the change in the yield stress of the truss due to heat. If the truss yields, then it will elongate a great deal without any further increase in stress. Also a basic concept.

There are more explanations as well:

Any damage to the web members of the truss would result in the top chord becoming more of a bending member than an axial only member. This will cause the stress in the top chord to increase and might even cause it to yield.

Localized point loads from very heavy objects (large pieces of the planes or debris from above) can overload the shear capacity of the truss. This would likely have the biggest effect if the point load was near the middle of the span of the truss as that is where an economical design will have the smallest web members.

Any large deflection in the truss, probably in the range of L/180 would crack the floor slab, further lowering the strength of the composite floor. Furthermore, floor slabs are NEVER used to brace steel columns as concrete has no tensile capacity. The only thing that braced the columns were the floor members.

[Heiwa]

Annnnnnnnd you just proved to me that you know nothing about structural engineering. Let's explain some concepts that you should have picked up in the second or third year of your undergraduate program:

The concrete slab in the WTC was composite with the floor trusses, which means that they acted together to resist bending moments. This translates to the concrete slab and the top chord of the truss being in compression, and the bottom chord of the truss in tension. Fairly basic concept for most people, you seem to be implying that the concrete did most of the work in holding the floors up.

The important point here, is how steel behaves when it is heating. You think that it only expands. Probably something you picked up watching a cooking show on TV. Something else important thing that changes is the modulus of elasticity. This modulus is the ratio of pressure to percent deformation. When the steel heats up, the modulus of elasticity goes down. So the bottom chord expierences higher amounts of elongation, hence sagging. This is immediately obvious to anyone who took a basic course in mechanics of materials, which you've either forgotten or never took.

There's something else that happens with the above, since the top chord is in compression and the bottom chord is tension, any increase in heat would result in strain compability issues with the web members. The web, being welded to the top and bottom chord of the truss, will be stretched as the bottom chord elongates and the top chord shrinks.

The above is probably the first explanation most engineers would come to when looking at a bending member that sagged due to heat. However it is not the only one.

The second one that comes to mind is the change in the yield stress of the truss due to heat. If the truss yields, then it will elongate a great deal without any further increase in stress. Also a basic concept.

There are more explanations as well:

Any damage to the web members of the truss would result in the top chord becoming more of a bending member than an axial only member. This will cause the stress in the top chord to increase and might even cause it to yield.

Localized point loads from very heavy objects (large pieces of the planes or debris from above) can overload the shear capacity of the truss. This would likely have the biggest effect if the point load was near the middle of the span of the truss as that is where an economical design will have the smallest web members.

Any large deflection in the truss, probably in the range of L/180 would crack the floor slab, further lowering the strength of the composite floor. Furthermore, floor slabs are NEVER used to brace steel columns as concrete has no tensile capacity. The only thing that braced the columns were the floor members.

So what? The vertical load on the floor assembly was only 20 kgs/m² = furniture and outfitting. No heavy members of an alleged plane landed on the floor! All that material flow in and out of the windows at once. If it was a plane? To me most fuel - 30 tons - also disappeared through the windows - at once. Why would the fuel stop inside the building, if it arrived at 800 kms/h? To me the impact looks like an explosion ... and not a plane impact. A plane impact would look completely different.

It is alleged that the temperature was high, so the steel and the concrete warmed up and material properties changed. And that the floors above impact sagged. But where is the evidence? As soon as the temperature falls again (the fire fades - only 20 kgs/m² of furniture burning you know) the material properties return to normal and the floor - even if deformed and with some cracked concrete - becomes an effective support again. The connections to the columns are still intact, i.e. the columns' supports are effective. And that accounts for 80% of the columns according NIST.

It seems on most photos that the fire was gone long before the sudden collapse ... that ensued. The small fires we see on photos are negligible. Just to roast a chicken on! So I assume most heat had escaped with the smoke, the temperature had fallen as fresh air was sucked in. It was not a big space and open all around. All columns in the south, west and north walls were effective then again before the collapse and could carry the 10-15% extra load from the failed east wall. So no global, sudden collapse could ensue. The mistake of NIST is that they ignore many things, e.g. that the temperature falls again, that the structure, even if damaged becomes more effective again, etc. But they were too afraid to admit it.

What a sloppy explanation of the collapse. It just ensued.

[The Almond]

[...]
I know steel expands due to heat ... but concrete!! No way. The floors were >95% concrete. And that combination supported the perimeter columns regardless of any sagging.
[...]


I would highly suggest reading any book on concrete. Mindness, Young and Darwin in Concrete 2nd edition list the coefficient for thermal expansion in concrete as between 7.4/C and 13/C. It lists the coefficient of thermal expansion for steel as between 11/C and 12/C. The PCA's Design and Control of Concrete Mixtures lists the value as 10/C. Jack McCormac's Design of Reinforced Concrete lists the value for reinforced concrete as between 9/C and 12/C.

So to answer your question, yes, concrete does indeed expand, deform and sag under load. The only appreciable difference between steel and concrete is in ductility and toughness, not in thermal expansion.

[Alferd_Packer]

Heiwa, a short and simple paper for your reading enjoyment:

http://fire-research.group.shef.ac.uk/Downloads/SC_Baltimore.pdf

(don't forget about my question regarding the DCRs)

[Newtons Bit]

OT but an easy one answered by Euler already 1744. The critical load P is

P = pi² x E x I / L² where L is the unsupported length of the column.

So if P = 100% when L is one unit, it is 25% when L is two units, it is 11.11 % when L is three units, etc. This is basic! Didn't you know Euler?

So you don't believe in inelastic buckling? Perhaps your studies in structural analysis would have led you to the path of Shanley and true column behavior, but ah well. Column buckling wasn't figured out until the middle of the 20th century. Euler buckling is only correct for extremely slender columns.

If you actually did REAL structural analysis, you would know this.

[maccy]

The small fires we see on photos are negligible. Just to roast a chicken on! So I assume most heat had escaped with the smoke, the temperature had fallen as fresh air was sucked in.

Why did people jump from the building if the fires weren't hot?

And where did all that smoke come from?

[Heiwa]

So you don't believe in inelastic buckling? Perhaps your studies in structural analysis would have led you to the path of Shanley and true column behavior, but ah well. Column buckling wasn't figured out until the middle of the 20th century. Euler buckling is only correct for extremely slender columns.

If you actually did REAL structural analysis, you would know this.

Of course - I was just testing this fool Alferd. And I like basics. But this is OT. We are discussing the NIST load re-distribution theory after alleged buckling of the east wall due lack of support and what happens to the core columns. OK - the core columns were not slender at all - some were box shaped - quite strong - why did they suddenly collapse? Did they buckle, compress, go up in smoke? You agree with NIST? Were they only softened?

Have you seen the core columns arrangement of WCT2? I was there a couple of times before the collapse on various floors. Looked very strong.

[Newtons Bit]

Heiwa, click the link below my post. I have actually calculated the compressive strength of the columns near the plane impact. It's overly conservative in favor of collapse prevent because it's based on Gordon Ross's assumptions.

If you REALLY knew what Euler buckling was, you wouldn't have used the I term, you would have used the more generic and modern (KL/r).

If you claim to be an engineer, use some actual engineering to make your arguments. Don't just use things you find on google, actually take the time to write a real paper with a real mathematical model. All your doing now is blowing smoke out of your filing cabinet.

[Heiwa]

In my comment #49 I quoted the NIST suggestion how global collapse ensued due to a small load distribution, which I queried. Nobody has so far explained why a small load distribution caused total collapse, so I assume we all agree that NIST suggestion is wrong. Most respondents have queried my knowledge about basic structural strength etc., which is of course OT.

But NIST is quite specific what happens when the east wall buckles and before total collapse ensues:

"The section of the building above the impact zone tilted to the east and south (observed at about 7° to 8° to east and about 3° to 4° to south, (…) as column instability progressed from the east wall to the adjacent south and north walls. The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued (sic)."

So now we turn from structural analysis to pure mechanics and dynamics.

Thus - due to the east wall collapse that started at time T and before global collapse ensued at time T + t1, i.e. in t1 seconds, the section above the impact zone tilted 7-8° to east due to release of potential energy. Assume that the section above is 100 metres high with its centre of gravity, CoG, at 50 metres above the impact zone. This means that the CoG of the section above shifted abt 6.14 metres to the east and the top of the lose section 12.28 metres to the east during time t1, before it started to fall straight down, when the south, west and north walls and the centre core collapsed - disappeared.

What is the rate of tilting (°/s) of the section above the impact zone at time t1. It was 0 °/s at time T but what was it at time t1? 15 °/s or more? As many observers have pointed out the section above the impact zone was completely undamaged and should evidently continue to rotate or tilt as it falls down. Its rotating momentum cannot be stopped.

How long time, t2, does it take for the undamaged section above the impact zone to fall down to the ground. Say its CoG was 350 metres above ground. Say that t2 is 8 seconds. How much should the 100 metres tall section above the impact zone rotate/tilt in that time? 120° or 90°? Did it? Or did it disappear in smoke?

You also wonder how the west part of the tower below the impact zone collapsed as there was no weight - potential energy - released above it. The potential energy that caused collapse - the intact section above the impact zone - was evidently shifting is CoG to east during the collapse. The CoG of section above the impact zone must in the end have been east of the east wall.

Regardless - the undamaged section above the impact zone obviously lands on top of rather on the east side of the remains of the tower that globally collapsed (for unknown reasons) below it.

Did it? I assume that the undamaged section above the impact zone should have landed more or less on its east wall side with the west wall on top, i.e. after the total collapse of the tower, we should have observed 100 metres of west wall columns on the east side of or on top of the rubble.

This 80 x 100 metres west wall column assembly should be more or less intact before it hits the ground/rubble on the ground and should then deform a little. It should have been easy to document this section. It was on top of everything.

Did anybody? Under the 100 metres of west wall columns, we should find 100 metres of 47 centre core columns, etc. They should be more or less continuous, i.e. one piece each but maybe deformed. It would have been easy to see how these core columns were torn apart at the impact zone.

But strangely enough it was not done. No forensic examination was done of section above the impact zone. It seems, which many observers have noted, that the intact section above the impact zone - four walls and its core - disintegrated in air between times t1 and t2. How to explain that? NIST does not explain it.

[Heiwa]

Do you believe that airliners hit the Twin Towers, the Pentagon, and a field in Pennsylvania on 9/11?

Good question. As I didn't see the incidents in person, I can only study the effects (holes in WCT1,2, Pentagon and a Pennsylvania field and rubble everywhere) and try to establish what caused them. Witnesses have given many different testimonies of what happened just before the impacts so I leave that analysis to others. It seems that forensic documentation of parts from any objects hitting the various locations is sloppy, so I have given up analysis of that too.

Subject here is of course the alleged by NIST load redistribution in WTC2 long after impact and what happens then. I have my doubts that global collapse ensued due to load redistribution as described by NIST, so what caused the global collapse? And how did the intact section above the impact zone get damaged, etc. It was the potential energy released, but it seems it flew away eastward during the collapse.

[stateofgrace]

Good question. As I didn't see the incidents in person, I can only study the effects (holes in WCT1,2, Pentagon and a Pennsylvania field and rubble everywhere) and try to establish what caused them. Witnesses have given many different testimonies of what happened just before the impacts so I leave that analysis to others. It seems that forensic documentation of parts from any objects hitting the various locations is sloppy, so I have given up analysis of that too.
Really ? I guess it is beyond your wildest dreams that planes that were hijacked by Islamic terrorists were the cause of all the death and destruction? I guess we should start to look for hidden explosives, missiles, maybe planes that flew over the buildings or hey maybe we should question whether sinister top secret US black guys staged it all in order to gain public support for the war on terror eh ?

Your analysis to date is one of wild speculation, based on wishful thinking and a desire to be oh so clever and spot something that the entire planet missed. You have failed, you have not spotted anything because there is nothing to spot other than your small anomalies that goes with every large event. An event that you and your like minded buddies wish to be a part of, you wish the importance that comes with this event upon yourself, again you will fail because you are not important, you are just some guy who plays at being the internet detective when the rest of the planet has moved on.

I guess the truth really is too terrifying for you, that being we really are hated , hated enough for 19 guys to board four planes, kill all their path and slam three of them into buildings full of innocent people. Is that enough truth for you ? Or did you actually fail to get the message that was sent to you on 911?I guess you did.




Subject here is of course the alleged by NIST load redistribution in WTC2 long after impact and what happens then. I have my doubts that global collapse ensued due to load redistribution as described by NIST, so what caused the global collapse? And how did the intact section above the impact zone get damaged, etc. It was the potential energy released, but it seems it flew away eastward during the collapse.


Really? and where exactly do you expect a massive dynamic weight that is falling on floor trusses to go? Just how on earth do you expect the floors that simply braced the external columns to core to support it ?

The core survived the collapse, the floors and the external columns did not, why oh why do you have such a difficult time with such a simple process. The weight fell on the floors,the floors were violently ripped away from the inner core and the external columns. The core collapsed later.

SIMPLE.

Oh wait maybe not, lets look at explosives, thermite, secret death squads, fires that could not possibly cause any further damage to a already damaged steel framed structure and while we are at it lets investiagte Flight 77 not hitting the Pentagon but actually flying over it . Oh wait theres more, lets all say the desperate calls from the passengers on flight 93 were faked, as was the crash site. Wow lets just make up all sorts of nonsense and pretent we are all self important.

Yeah sure, what ever you say Mr Offshore Structural Engineer ( not).

[Dog Town]

The small fires we see on photos are negligible. Just to roast a chicken on!

You must have acre sized BBQ's, per chicken. Are you for real?

[Heiwa]

Heiwa, click the link below my post. I have actually calculated the compressive strength of the columns near the plane impact. It's overly conservative in favor of collapse prevent because it's based on Gordon Ross's assumptions.

If you REALLY knew what Euler buckling was, you wouldn't have used the I term, you would have used the more generic and modern (KL/r).

If you claim to be an engineer, use some actual engineering to make your arguments. Don't just use things you find on google, actually take the time to write a real paper with a real mathematical model. All your doing now is blowing smoke out of your filing cabinet.

Interesting link. So there are two possibilities - global collapse ensues (NIST) or global collapse should have been prevented (and something else initiated the collapse). Anyway - global collapse was prevented for some time, so the structure was not too bad ... until it suddenly disintegrated due load redistribution. It is a pity that a forensic analysis was nor carried out of the structural parts in question. Of course I am an engineer, but I try to explain matters in layman terms for easy understanding. It is very practical when working in the field with welders and platers, etc. I can do 3D FEM/beam analysis, etc. but the input has to be correct, e.g. the actual conditions and loads. And NIST establishing actual conditions and loads is sloppy. And then it is very easy to chose some assumed conditions and loads to achieve the given result. I have seen it before.

Interesting reactions on this forum. Many believes anything and do not like open discussions.

[Heiwa]

Really ? I guess it is beyond your wildest dreams that planes that were hijacked by Islamic terrorists were the cause of all the death and destruction? I guess we should start to look for hidden explosives, missiles, maybe planes that flew over the buildings or hey maybe we should question whether sinister top secret US black guys staged it all in order to gain public support for the war on terror eh ?

Your analysis to date is one of wild speculation, based on wishful thinking and a desire to be oh so clever and spot something that the entire planet missed. You have failed, you have not spotted anything because there is nothing to spot other than your small anomalies that goes with every large event. An event that you and your like minded buddies wish to be a part of, you wish the importance that comes with this event upon yourself, again you will fail because you are not important, you are just some guy who plays at being the internet detective when the rest of the planet has moved on.

I guess the truth really is too terrifying for you, that being we really are hated , hated enough for 19 guys to board four planes, kill all their path and slam three of them into buildings full of innocent people. Is that enough truth for you ? Or did you actually fail to get the message that was sent to you on 911?I guess you did.





Really? and where exactly do you expect a massive dynamic weight that is falling on floor trusses to go? Just how on earth do you expect the floors that simply braced the external columns to core to support it ?

The core survived the collapse, the floors and the external columns did not, why oh why do you have such a difficult time with such a simple process. The weight fell on the floors,the floors were violently ripped away from the inner core and the external columns. The core collapsed later.

SIMPLE.

Oh wait maybe not, lets look at explosives, thermite, secret death squads, fires that could not possibly cause any further damage to a already damaged steel framed structure and while we are at it lets investiagte Flight 77 not hitting the Pentagon but actually flying over it . Oh wait theres more, lets all say the desperate calls from the passengers on flight 93 were faked, as was the crash site. Wow lets just make up all sorts of nonsense and pretent we are all self important.

Yeah sure, what ever you say Mr Offshore Structural Engineer ( not).

Thank you but you are 200% OT as we discuss another matter - alleged load re-distribution and its effects on WTC2.

[stateofgrace]

Interesting link. So there are two possibilities - global collapse ensues (NIST) or global collapse should have been prevented (and something else initiated the collapse). Anyway - global collapse was prevented for some time, so the structure was not too bad ... until it suddenly disintegrated due load redistribution. It is a pity that a forensic analysis was nor carried out of the structural parts in question. Of course I am an engineer, but I try to explain matters in layman terms for easy understanding. It is very practical when working in the field with welders and platers, etc. I can do 3D FEM/beam analysis, etc. but the input has to be correct, e.g. the actual conditions and loads. And NIST establishing actual conditions and loads is sloppy. And then it is very easy to chose some assumed conditions and loads to achieve the given result. I have seen it before.

Interesting reactions on this forum. Many believes anything and do not like open discussion s.

That is because I am close minded and beleive every single thing that my Government tell me, I am a sheep you see, I simply all fall in and obey the NWO. Oh Wait...............

Maybe , just maybe all your bunk as already been debunked , maybe just maybe that people actually find it quite offensive when internet detectives start accusing perfectly innocent people of being involved in mass murder.

You see, sunbeam you are actually acussing your fellow countrymen of mass murder and trying to excuse the real terrorists who committed this wicked act. So my learned fellow offshore worker( not) maybe you can start your open discussion by explaining to me why on earth I should listen to a word you say. Why should I listen to somebody who is trying to tell me that every single event that took place on 911 is not as it seems? You are the detective you are the one doing all the investigating , not me, I have no such delusions of grandeur, this is because I believe everything I am told, oh wait...... except your bunk that is.

So in the spirit of fair play and open discussion why don't you tell me what happeend on 911, no more "I'm just asking questions", no more sliding out of it, a simple summary of the day events. It goes something like this.

" On 911 four planes were hijacked by Islamic terrorists, two hit the towers, which burnt and then fell down. They fell on top of other buildings , which also fell down. A third plane hit the Pentagon and the forth crashed after the passengers fought back. A Group called Al Qaeda have repeadley claimed responsibility for this attack"

Now that is a simple summary, please offer up your own, do not have a go at mine, after all I am just a sheep who buys into anything, so why don't you tell , in your own words what happened?

[Lurker]

I can do 3D FEM/beam analysis, etc. but the input has to be correct, e.g. the actual conditions and loads. And NIST establishing actual conditions and loads is sloppy. And then it is very easy to chose some assumed conditions and loads to achieve the given result. I have seen it before.


You have actually seen the details behind the FEA? Have you seen how they arrive at the assumptions of boundary conditions and loads?

In your FEMs, do you perform coupled heat transfer/structural analysis?

Lurker

[Panoply_Prefect]

You see, sunbeam you are actually acussing your fellow countrymen of mass murder

Just to clarify, Heiwa is swedish (although techically an expat living in France), not american.

Cheers,
SLOB

[The Almond]

Interesting reactions on this forum. Many believes anything and do not like open discussions.

Before I start with the analysis of your claims, I'd just like to ask a few questions.

1) If we believe anything without critical thought or analysis, why don't we believe you?
2) If someone were to come onto an internet forum, fail to address arguments presented to him, and routinely declare discussion points "off topic" instead of addressing them, would you call him a facilitator of an open discussion? Do people who do that really facilitate open discussion?

[GlennB]

....
Have you seen the core columns arrangement of WCT2? I was there a couple of times before the collapse on various floors. Looked very strong.

That's a very strange statement.

Care to clarify?

[Heiwa]

You have actually seen the details behind the FEA? Have you seen how they arrive at the assumptions of boundary conditions and loads?

In your FEMs, do you perform coupled heat transfer/structural analysis?

Lurker

I have no problems to establish the actual conditions of structural parts and their boundary conditions before impact. The model is just the damaged floors and the intact section above. All parts are beams except the core box columns that are FE. The loads I know. After the impact the structure stands and I can model that by removing the damaged parts as proposed by NIST. The model is stable. But then it becomes complicated.

I assume that the perimeter columns are not affected by heat as they are outside the fire. I also assume the core columns are not affected by the heat (because it it unclear how hot it was at the various columns). NIST suggests that the floors sags due to heat and this I can model in different ways as long as the boundary conditions remain unchanged, i.e. the floors are connected to the columns. I can manually change the truss material properties. The vertical load on the trusses is small so sagging is small. The model is still stable. I can also model what happens if some trusses cool down again. The situation improves.

But if the floors starts to detach from the columns due heat + sagging I cannot model that because I have no idea if, where and how it takes place. Everything becomes guesswork. But why would the trusses be ripped of the columns due fire long after the impact? Has it happened in other fires? So I assume the floor trusses do not detach from the columns. The model is thus stable. The function of the trusses (+ concrete) are just to support the columns. Axial loads (tension) are transmitted by the trusses even if sagged but they are small.

I can remove the perimeter columns of the east wall (assumed buckled and not connected to the Trusses/floors) and observe the load re-distribution. The weight of the intact section above is shifted to the remaining walls and the core and the model still stands. No global collapse ensues. There was plenty of redundancy, it appears.

[T.A.M.]

interesting he would have access to the core column arrangement of the WTC. Was that part of the standard tour...lol

TAM:)

[Panoply_Prefect]

Good question. As I didn't see the incidents in person, I can only study the effects (holes in WCT1,2, Pentagon and a Pennsylvania field and rubble everywhere) and try to establish what caused them.


Ignoring the heaps of witness testimony who actually saw the planes hit the Twin Towers and the Pentagon - not to mention that the NY planes were caught on video - which should help give a clue as to what actually exploded at and in those buildings.

Oh, or let me put it like this:

Do you believe that videos that show planes hit the Twin Towers are forged?

Do you believe that the witnesses who saw a plane hit the Pentagon are lying?

Two rather simple questions.


Cheers,
SLOB

[Belz...]

I don't know how to quote above with sub-quotes but here we go.

The first thing you should learn is not how to quote, but how to read. Many of the things you state below are adressed in the post you were responding to.

There was no load on the floors above, except their own weight + furniture.

Which is already compromising when the head makes the steel useless.

Why concrete floors + steel trusses would then sag due to heat is beyond me but it will not be much. I know steel expands due to heat ... but concrete!! No way.

You do understand how floors hold together, don't you ?

The floors were >95% concrete.

>95 % ?

And that combination supported the perimeter columns regardless of any sagging.

Precisely. So what do you think bore the brunt of the stress once they started to sag ?

And we can SEE the sagging on the pictures and videos. How can you ignore that ?

Sorry - one (east) wall - supporting only 12.5% of the total load cannot initiate total global collapse.

Yeah, I'm sure that top section would've held just fine without those walls. :rolleyes:

Why - the other structure, particularly the core, will easily support the load transferred to it. Basic. It is seen on the photos! The east wall is deformed ... and the other parts are intact. The tower stands.

So your reasoning is that if the tower didn't fall immediately following the impact, it shouldn't have collapsed at all ??

And suddenly the whole thing explodes!

The word you are looking for is collapses.

But videos of the roof - far above - shows that it sags a little before that = the 47 core columns apparently failed before the east wall.

There is no reason to believe that the core columns failed and caused the collapse. I told you:

We can see the core STILL STANDING after the collapse of the perimeter is completed.

Similar to WTC7? Strange case. But support for Controlled Demolition.

Only if you assume that a CD is the only way to produce this effect.

It would have been easy to check why the 47 off 400 metres tall core columns failed by proper forensic examination. But it was not done. This is why I suspect an Inside Job.

And that's funny, because the REASON why it wasn't done is because there was no REASON to suspect foul play. We SAW the planes crash into the towers, we SAW the effect of the fires on the structure and NOTHING in the collapse is suspicious. Why the hell would you suspect foul play ?

And it is easiest decided by a re-hearing of the whole case in a law court. I actually believe in the Law of Justice. Do you?

Yes, and your theories would be laughed at by a judge.

[Belz...]

So what? The vertical load on the floor assembly was only 20 kgs/m² = furniture and outfitting.

Who cares ? The metal EXPANDED without the need for excess weight.

Also, please don't forget that the floor itself has mass, and that heat doesn't help steel to withstand that.

Why would the fuel stop inside the building, if it arrived at 800 kms/h?

Actually, that's a false dichotomy. The fuel was spread.

To me the impact looks like an explosion ... and not a plane impact. A plane impact would look completely different.

Evidence ?

And what do you think an explosion is ?

It is alleged that the temperature was high, so the steel and the concrete warmed up and material properties changed. And that the floors above impact sagged. But where is the evidence?

The evidence is, this is how things work.

It seems on most photos that the fire was gone long before the sudden collapse ...

Then what was all that smoke doing there ?

The small fires we see on photos are negligible. Just to roast a chicken on!

I don't know why you feel the need to mock the events of that day.

So I assume most heat had escaped with the smoke, the temperature had fallen as fresh air was sucked in.

Actually, that's not how fires work. Fresh air doesn't help.

So no global, sudden collapse could ensue.

Engineers and experts around the world disagree with you.

What a sloppy explanation of the collapse. It just ensued.

Yes. It ensued. I don't think that word means what you think it means.

[Heiwa]

So my learned fellow offshore worker( not) maybe you can start your open discussion by explaining to me why on earth I should listen to a word you say. Why should I listen to somebody who is trying to tell me that every single event that took place on 911 is not as it seems? You are the detective you are the one doing all the investigating , not me, I have no such delusions of grandeur, this is because I believe everything I am told, oh wait...... except your bunk that is.



If you have read the 9/11 Commission report about all events that took place on 9/11 prior impacts as I assume you have, do you believe everything in it? I do not (and millions others). It is too much fiction and fantasy in the report.
But my main interest is the analysis of structural damages after impacts, i.e. the results of forensic examinations ... or the lack of them.

WTC2 was the first tower that collapsed. I assume the people trapped in the section above thought they were safe and that the tower would not collapse as the fire slowly went out. But then WCT2 suddenly collapsed ... and NIST is coming up with some suggestions why that we are discussing. Controlled demolition is evidently not investigated by NIST.

The people trapped in the WCT1 must have been horrified when WTC2 collapsed. I assume they concluded their tower would also collapse ... and some desperate persons decided to jump before that, etc. Terrible.

I see no harm in discussing WTC2 and what happened to its structure after impact and prior to the global collapse that ensued.

NIST alleges that the east wall suddenly buckled and that there was load redistribution which caused the collapse. But it is not certain. Very little is certain.

NIST says that the intact section above tilted 7-8° to east prior collapse, but then the west part of the tower could not really be damaged as it was. And where did the intact section land?

With all respect to NIST they should have spent less ink/paper on the design, construction, maintenance and fire protection of the tower and descriptions of fires after impact and prior collapse. Much more efforts should have been spent on the structural conditions of the tower after impact and prior collapse and forensic examinations of the rubble that could explain the collapse.

[T.A.M.]

Heiwa:

with all respect to you sir, NIST was mandated to do those exact things you have said they should have spent less time on. Should they have gone against that mandate, and if so based on whose request or suggestion? They were never asked to be a forensic investigation, despite what the truth movement seems to think they should have been.

TAM:)

[twinstead]

NIST was NOT tasked to analyze the event post collapse, if I recall.

[Panoply_Prefect]

The people trapped in the WCT1 must have been horrified when WTC2 collapsed. I assume they concluded their tower would also collapse ... and some desperate persons decided to jump before that, etc. Terrible.


So a) nobody jumped prior to the collapse of WTC2 and b) nobody from WTC2 jumped?

Is this correct?

Cheers,
SLOB

[Heiwa]

That's a very strange statement.

Care to clarify?

In the 90's I visited American Bureau of Shipping (93rd floor?) and some other companies high up in the WTCs and I am always curious about escape routes, fire protection, etc. if the lifts fail, fires break out, etc. so I had a look around. Also interior decoration ... how to hide the supporting columns in the entry hall at every floor. I was quite impressed but would never work in such a tower.

Actually the purpose of the visit to ABS was to discuss a better, safer and more environmentally protected seagoing oil tanker design that spills zero oil in most incidents - the Coulombi Egg tanker! http://heiwaco.tripod.com/ce_coulombiegg.htm . In 1997 the United Nations International Maritime Organziation approved it as an alternative to double hull according international rules. Quite an achievement! It is the only design that has been so approved by the IMO. Unfortunately one member of the IMO did not agree! The USA. So USA had to abandon the international rules and make their own rules.

You can note that the Coulombi Egg design is based on data of actual incidental damages to oil tankers! Most collision damages are actually located only above and in the waterline, so the Coulombi Egg logic was to maximize the protection there. The USCG apparently disagreed. They thought a flimsy, uniform 'protection' all the way down to the bilge (double side) was better. It was very easy to demonstrate the opposite. The USCG was not happy. Strange case.

But above explains my interest in the WTC2 collapse. What caused it? How to prevent it happen again.

[GlennB]

I assume that the perimeter columns are not affected by heat as they are outside the fire.

That's quite an assumption ...

http://i95.photobucket.com/albums/l131/Ignatz_CT/WTC1latefires.jpg


I also assume the core columns are not affected by the heat (because it it unclear how hot it was at the various columns)



You don't know how hot it was, therefore you assume room temperature?
Er .....

[Gravy]

Good question. As I didn't see the incidents in person, I can only study the effects (holes in WCT1,2, Pentagon and a Pennsylvania field and rubble everywhere) and try to establish what caused them. Witnesses have given many different testimonies of what happened just before the impacts so I leave that analysis to others. It seems that forensic documentation of parts from any objects hitting the various locations is sloppy, so I have given up analysis of that too. Thank you for your honest answer. As I don't waste time with people who can't figure out if airliners were used in the 9/11 attacks, I wish you well in your pursuits and bid you goodbye.

[T.A.M.]

And here I thought Heiwa was an NWO disinfo agent/explosives specialist who was part of the CD team for the towers...

Oh well, welcome to the forum, a litte belated, Heiwa.

TAM:)

[The Almond]

I am a structural engineer specialized in shipbuilding. I have inspected many ships built of steel damaged by fire and overload of various kinds.

I don't care. I care about mathematics, evidence and logical analysis.

None of these ships or their structures has ever collapsed by fire. Deformed, yes. I have some observations regarding the WTC2 collapse that may be of interest:

This point has been shown in error.

The NIST NCSTAR 1-6D report suggests that the WTC2 collapse was due to the following:

"Buckling of East Wall and Collapse Initiation

With continuously increased (sic) bowing and axial loads, the entire width of the east wall buckled inward. The instability started at the center of the wall and rapidly progressed horizontally towards the sides. As a result of the buckling of the east wall, the east wall significantly unloaded, redistributing its load to the softened core through the hat truss and to the south and north walls through the spandrels ( …). The section of the tower above the buckled wall suddenly moved downward, and the building tilted to the east ( …).


The section of the building above the impact zone tilted to the east and south (observed at about 7° to 8° to east and about 3° to 4° to south, …) as column instability progressed from the east wall to the adjacent south and north walls. The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued (sic)."

That's page 321 in case anyone else is following along.

According to other NIST reports the total mass above was supported as follows:

50% - by the 47 core columns.
12.5 % - by the south wall columns (abt 80)
12.5% - by the east wall columns (abt 80)
12.5% - by the north wall columns (abt 80)
12.5% - by the west wall columns (abt 80).


A side note here, the corner columns of the WTC complex held, by themselves, about 1/5th of the load on the core. See NCSTAR 1-1, page 8 for details on the structural subsystems.

About 80% of the wall and core columns were intact after first impact according NIST and the tower structure carried the mass above.

Again, columns that were in tact did not necessarily have the same load capacity as they did before impact. Your analysis seems to hinge on the idea that any in tact column is still capable of carrying 100% of the load. That's a ridiculous assumption.

Then there were fires in the office spaces between the core and the outer walls. The outer wall columns were always cooled by fresh air so they were unaffected by the heat.

Excuse me? Just because a column is cooled by fresh air on one surface does not mean it is impervious to effects by heat. That is a wildly inaccurate statement. Section 3.2.1 shows NIST's analysis of the heat effects in the exterior wall for WTC 1.

We are told that the east wall, that carried 12.5% of the mass above, buckled inward due to axial loads some minutes before the collapse, which BTW are constant and not increasing, as suggested. The buckling deformation is not big as there is still some support from floors inside.


Actually, we're told that the columns on the east wall buckled due to a combination of increased axial load and increased out of plane loading due to floor sagging. These are the infamous "pull in" forces that are discussed, oh, maybe 100 times in 1-6D. Read page 310 for further details. It seems as though you're intentionally misrepresenting NIST's findings.

Second, while the collapse happened suddenly,
We are then told that the east wall significantly unloaded but not how much.

We are told the column loads prior to buckling.

Let's say that 50% of the load on the east wall that originally carried 12.5% of the total mass above, i.e. 6.25% of the total mass above is now redistributed to (i) the core, and to the (ii) south and (iii) north walls through connecting structure.

That's complete nonsense. You've pulled that number out of thin air and assumed that it completely redistributes to areas of the WTC towers which you assume are undamaged by fire. How does that assumption have any basis in reality?

NIST describes, in detail, a load cycling from damaged exterior columns to less damaged exterior columns, and further to the core columns. It is a cycle which catastrophically collapsed when load redistribution failed. 30 minutes into the collapse, creep strain was already buckling core columns where the temperature stresses were high. See pages 313 to 318 for the details.

So 6.25% of the total mass above is redistributed. What happens?

It is redistributed to an area heavily damaged by fire. An area that, by the way, continues to shed thermal load onto the exterior columns via the Hat Truss system. Load can't cycle both ways, and when one system fails, all of them do.

Say that 50% of that or 3.125% of the total mass above is redistributed to the core; it will then carry 53.125% of the total mass above. Thus the load on the core increases 6.25% after the alleged redistribution.

Again, you pulling numbers out of thin air is not convincing.

We are told that the core is 'softened' which is not scientific but maybe it was affected by heat.

Maybe? Maybe it was affected by heat? Did you read any of the NCSTAR? Do you understand anything about fire or the effect of heat on steel?

However, half of the core columns were far away from any fires so they could hardly have been affected.

Excuse me? You're talking about load redistribution, and you assume that the only way a column can be damaged is if it is directly damaged by fire or impact? What about load redistribution? Do increased loads and additional thermal stresses also deform and damage columns?

But as the core columns had resisted the fire so far, a load increase of 6.25% due to redistribution could not make the core collapse!

Wow! An argument from personal incredulity! Not only that, you're assuming that because the core columns were able to carry the increased load directly after the impact, they should have been able to hold the weight indefinitely. That's silly.

25% of the redistributed load or 1.5625% of the total mass went into the south and north walls respectively that now each carries 14.0625% of the total mass above. Thus the load on the south and north walls increased 12.5%. These walls were not affected by fire as they were cooled by fresh air. There were some damage to the south wall, but again it did not collapse at impact, so a load increase of 12.5% will make little difference. No deformation of any kind is seen on the north and south walls after redistribution.

Once again, you making up numbers is not a convincing scientific argument.

Global collapse could therefore not ensue due to such load distributions because there were too much redundancy and safety factors built into the outer wall columns (wind, lateral loads, etc) and also in the core columns. You could maybe expect further deformations of structure finding a new equilibrium and the tower may have tilted a little and stopped in that position but sudden global collapse is impossible due to the alleged load distribution!

Ok, your argument was based on the idea that redundancy could have handled the impact of the aircraft and the increased thermal stress due to fire indefinitely. Yet you provide no mathematics to prove it, and your best effort is to make up numbers, fail to account for thermal stresses, and assume infinite load distribution on a static system.

Actually there is no evidence of any sort for the statement "Global collapse ensued".

I can't tell if this statement is sarcastic or stupid.

It is only wishful thinking by incompetent and/or complacent NIST engineers. They know that no steel skyscraper has ever collapsed due to fire!!

So, hundreds of the world's best civil, structural and materials engineers are wrong. As are their academic, professional and international collaborators, reviewers, and the various professional societies to which they belong. And your belief is that they're incompetent.

So what happened? Controlled demolition, CD, from top down? It seems that WCT 2 47 off core columns were damaged first, as the tower actually falls in its own footprint. The outer wall columns break afterwards like spaghetti by the floors being pulled down by the core columns. It seems that the core columns were broken by CD at every 10th floor, or so. NYFD staff noted these explosions, bang, bang, bang just before collapse ensued.

I would implore you to take a logic class. On your first day, the first words from your teacher's mouth will be, "Universal affirmatives can only be partially converted." The fact that all explosives cause explosions does not imply that all explosions are cause by explosives.

It would have been very easy to recover all the bits of the core columns from the rubble and assemble them on a 400 meter long field to verify (a) in how many parts each column split during collapse and (b) how the surface of the broken areas looked like.

I'm glad that your opinion is that it would be "very easy" to recover the core columns. It's too bad no one cares about your opinions.

CD would probably have cut of the core columns sideways to dislocate them so that they could just drop down pulling other structure with them.

That would have caused a radically different collapse than the one seen. The core of WTC 1 and WTC2 remained standing for several seconds after the exterior of the building had collapsed.

Alternatively complete pieces of core columns were blown away. In either case a forensic examination of the core columns would have explained the collapse.

A forensic examination was completed. It is the subject of a 10,000 page report completed by the most advanced and experienced building fire research lab in the country.

If the collapse was due to release of potential energy overstraining the core pillars, the broken areas would look completely different.

I don't care about your opinion.

But as no complete forensic examinations were done for unknown reasons we must find other means to establish the real cause of the collapse. Easiest is of course a complete re-hearing of the case by a competent law court.

Wow! So, lawyers are better able to judge the technical veracity of the NCSTAR than engineers and scientists in the field. I had no idea that the courts were in the business of establishing scientific truth!

[Alt+F4]

As I didn't see the incidents in person, I can only study the effects (holes in WCT1,2, Pentagon and a Pennsylvania field and rubble everywhere) and try to establish what caused them. Witnesses have given many different testimonies of what happened just before the impacts so I leave that analysis to others. It seems that forensic documentation of parts from any objects hitting the various locations is sloppy, so I have given up analysis of that too.

So where did all those dead bodies come from?

[Belz...]

Nobody has so far explained why a small load distribution caused total collapse

Maybe because it's a strawman.

so I assume we all agree that NIST suggestion is wrong.

Sorry, no cigar.

Regardless - the undamaged section above the impact zone obviously lands on top of rather on the east side of the remains of the tower that globally collapsed (for unknown reasons) below it.

Again, you're assuming your conclusion. The tower "below it" collapsed because 40 floors were crashing onto it.

Did it? I assume that the undamaged section above the impact zone should have landed more or less on its east wall side with the west wall on top, i.e. after the total collapse of the tower, we should have observed 100 metres of west wall columns on the east side of or on top of the rubble.

Well, then it's a good thing that the people making the REAL analyses are those who know what they're talking about.

Did anybody? Under the 100 metres of west wall columns, we should find 100 metres of 47 centre core columns, etc. They should be more or less continuous, i.e. one piece each but maybe deformed. It would have been easy to see how these core columns were torn apart at the impact zone.

Why the hell would you expect that ?

But strangely enough it was not done. No forensic examination was done of section above the impact zone. It seems, which many observers have noted, that the intact section above the impact zone - four walls and its core - disintegrated in air between times t1 and t2. How to explain that? NIST does not explain it.

Again, why should they ? Something that massive won't stay in one piece for long when such forces are involved.

[Belz...]

Anyway - global collapse was prevented for some time, so the structure was not too bad ... until it suddenly disintegrated due load redistribution.

Again, why do you assume that the damage was not progressive ?

Of course I am an engineer

A garden engineer ?

Interesting reactions on this forum. Many believes anything and do not like open discussions.

That's funny because that's exactly what we're doing. Discussing.

But if the floors starts to detach from the columns due heat

Again: who said anything about detaching, except you ?

[Belz...]

If you have read the 9/11 Commission report about all events that took place on 9/11 prior impacts as I assume you have, do you believe everything in it? I do not (and millions others).

These things cannot be a matter of belief.

It is too much fiction and fantasy in the report.

How do you know it's fiction if your entire reasoning is based on simple incredulity ? It seems very circular, to me.

WTC2 was the first tower that collapsed. I assume the people trapped in the section above thought they were safe and that the tower would not collapse as the fire slowly went out.

And that's why they jumped.

But then WCT2 suddenly collapsed ... and NIST is coming up with some suggestions why that we are discussing. Controlled demolition is evidently not investigated by NIST.

Because it's nonsensical. How could someone prepare the WTC tower for demolition, a job that would take months, while people were werking 24/7 in that tower, and risk wrecking that work by slamming huge airplanes into the tower just a few minutes before detonating the soundless, invisible explosives ?

NIST alleges that the east wall suddenly buckled and that there was load redistribution which caused the collapse. But it is not certain. Very little is certain.

Simply saying that something is not certain does not raise actual suspicion, Heiwa.

NIST says that the intact section above tilted 7-8° to east prior collapse, but then the west part of the tower could not really be damaged as it was. And where did the intact section land?

What intact section ? The tower collapsed.

With all respect to NIST they should have spent less ink/paper on the design, construction, maintenance and fire protection of the tower and descriptions of fires after impact and prior collapse.

Why ? That was their job. Why would they spend more time on anything ?

Much more efforts should have been spent on the structural conditions of the tower after impact and prior collapse and forensic examinations of the rubble that could explain the collapse.

Why ? We saw the planes crash into the towers. We saw the progressive effect of the fires, and we have a perfectly good explanation as to what happened to trigger the collapse. We also have confirmed suspects and evidence to prove their involvement.

[Alferd_Packer]

Of course - I was just testing this fool Alferd. And I like basics.

yeah, right.

Still tap dancing around the questions, I see.

[stateofgrace]

If you have read the 9/11 Commission report about all events that took place on 9/11 prior impacts as I assume you have, do you believe everything in it? I do not (and millions others). It is too much fiction and fantasy in the report.

Many members have already addressed your points, repeatly, but I would like to pass comment on this little gem. Along with a few other gems your have posted. I take it that is ok? Since we are having an open discussion and all that stuff. Yes I have read the 911 commission report, thats the one that say Al Qaeda carried out the attack right? The same report that says 19 guys who subscribe to this ideology carried out the attack right ?

Yes I do beleive this is generally correct and I beleive that billions of other people on the planet also beleive it to be correct. So were exactly do you get the figure of millions of Americans from ? maybe you pulled it from somewhere? You didn't make it up did you, you wouldn't just say that to try and impress people would you? After all you are after the truth are you not ? You couldn't just start telling stories would you? the only fiction and fantasy comes from you sunbeam, prentending that millions of people support you. Is it a comfort thing you seek, thinking millions all think like you? Does it make you feel you not so isolated,?

But my main interest is the analysis of structural damages after impacts, i.e. the results of forensic examinations ... or the lack of them.

WTC2 was the first tower that collapsed. I assume the people trapped in the section above thought they were safe and that the tower would not collapse as the fire slowly went out. But then WCT2 suddenly collapsed ... and NIST is coming up with some suggestions why that we are discussing. Controlled demolition is evidently not investigated by NIST.Now this gem is the lock , stock and barrel of the truther, you assume? You assume what pal? How dare you assume you have any idea how terrifying it must have been for anybody trapped inside those towers? How dare you use your assumption to fuel you fantasies? You assume the fires had gone out and you assume that everybody felt save, .It may have slipped your mind but two very large planes had just been slammed into each tower, they had fires inside them and you drag another inane comment out, assuming that everybody inside one of the towers felt safe?

Your assumption aside, the firefighters inside WTC 1 did not even know that a second plane hit the second tower and they did not know it had collapsed, they did not see it ,they heard it. many people inside WTC 1 would not have even seen WTC 2 collapse simply because of the side of the building they were on, but you in your infinate wisdom make assumptions of jaw dropping insensitivity.

Controlled demolition was not investigated any more than little green men with lazer beams was investigated, becasue the most plausible senario which fits all the facts is that the damage from the planes and the fires brought down the towers. Maybe they didn't assume like you, anything, maybe , just maybe they used science and physics, but hey you would know all about that wouldn't you ?

The people trapped in the WCT1 must have been horrified when WTC2 collapsed. I assume they concluded their tower would also collapse ... and some desperate persons decided to jump before that, etc. Terrible. More assumptions, see above. You are not in a postion to assume anything. Do not assume that you will be shown anything other than the same distaste, I have for any other conspirator who mocks this event. If you assume this, you will be wrong.

I see no harm in discussing WTC2 and what happened to its structure after impact and prior to the global collapse that ensued. Neither do I , give it you best shot, opps sorry you already did and got torn apart, try harder next time.

NIST alleges that the east wall suddenly buckled and that there was load redistribution which caused the collapse. But it is not certain. Very little is certain.Yes there is very little that is certain when you make wild assumptions, but hey lets assume I am actually bothered what you say anymore. Lets assume that I actually am wondering why you have not offered up any answers to the questions I have asked you. lets assume that you are not ignoring these questions but actually giving them some serious thought. So based on these assumptions, are you actually going to try and answer them?

NIST says that the intact section above tilted 7-8° to east prior collapse, but then the west part of the tower could not really be damaged as it was. And where did the intact section land?

With all respect to NIST they should have spent less ink/paper on the design, construction, maintenance and fire protection of the tower and descriptions of fires after impact and prior collapse. Much more efforts should have been spent on the structural conditions of the tower after impact and prior collapse and forensic examinations of the rubble that could explain the collapse.The collapse as been explained and countless billions accept it. Maybe you should write to NIST and tell them all about it, maybe you should tell them they got it all wrong and that fires don't effect steel framed structures and fires have never caused any to collapse and the fires went out inside WTC 2 and everybody inside WTC 1 saw WTC 2 collapse and decided to jump. I assume they will tell you exactly what to do.

[T.A.M.]

The only thing certain is that a group of highly trained scientists, with more qualifications among them than all the truthers combined, studied the collapses and came to the conclusions in the NIST report.

TAM;)

[gumboot]

Reading Heiwa's posts gives me a headache.

-Gumboot

[LashL]

So a) nobody jumped prior to the collapse of WTC2 and b) nobody from WTC2 jumped?

Is this correct?

Cheers,
SLOB

No, that is not correct. Sadly, there were people jumping to their deaths long before the collapse of WTC2. The Naudet brothers video, the book 102 Minutes, and numerous eyewitness accounts make this horrifically apparent. :(

[BillyRayValentine]

The people trapped in the WCT1 must have been horrified when WTC2 collapsed. I assume they concluded their tower would also collapse ... and some desperate persons decided to jump before that, etc. Terrible.

What's terrible is when some fraud misstates nearly every pertinent fact with respect to an event that killed thousands. And then tries to speak authoritatively about it.

It's particularly offensive to New Yorkers like myself, who were close enough to get a real sense of the massive fires, and close enough to see the steady stream of HUMAN BEINGS forced to jump to their deaths to escape the agonizing heat. AND THEY STARTED JUMPING LONG BEFORE WTC2 COLLAPSED you absolute insect.

Those memories will forever be seared in my mind.

[BillyRayValentine]

So a) nobody jumped prior to the collapse of WTC2 and b) nobody from WTC2 jumped?

Is this correct?

Cheers,
SLOB

People in WTC1 started jumping long before WTC2 collapsed.

My view of WTC2 was largely obscured, so I can't answer b. with complete certainty. Since many people had left the tower, and it burned for only about half the time of WTC1 before collapsing, we can expect that, if it happened at all, the number would be far less for WTC2.

[Panoply_Prefect]

No, that is not correct. Sadly, there were people jumping to their deaths long before the collapse of WTC2. The Naudet brothers video, the book 102 Minutes, and numerous eyewitness accounts make this horrifically apparent. :(

People in WTC1 started jumping long before WTC2 collapsed.

My view of WTC2 was largely obscured, so I can't answer b. with complete certainty. Since many people had left the tower, and it burned for only about half the time of WTC1 before collapsing, we can expect that, if it happened at all, the number would be far less for WTC2.

Tnx for the replies guys. I was rather sure that Heiwas statement was bull, but the thing is with him, you can't accept anything he says at face value. He has no problems whatsoever with pulling things out of thin air, just to fit his own theory, and when questioned about it he's an expert at dodging and avoiding to give answers to his claims. And when he does he nine times out of ten invents something new, and equally unfounded.


So Heiwa, your explanation to why people jumped doesn't hold. What does that do to your theory?

/S

[LashL]

He has no problems whatsoever with pulling things out of thin air, just to fit his own theory, and when questioned about it he's an expert at dodging and avoiding to give answers to his claims. And when he does he nine times out of ten invents something new, and equally unfounded.

This is common behaviour among troofers. I think they take lessons from Alex Jones.

So Heiwa, your explanation to why people jumped doesn't hold. What does that do to your theory?

Well, Heiwa?

[Heiwa]

So Heiwa, your explanation to why people jumped doesn't hold. What does that do to your theory?

/S

Nothing. The topic raised by me is the NIST statements about WTC2 collapse. There is no evidence that global collapse ensued due to the alleged east wall buckling i.w.o. the impact area causing load redistribution. There are pictures/videos showing the wall being deformed - none that it collapses causing load redistribution, etc. NIST suggests the core was softened, etc. but there is no evidence.

Then there is the NIST statement about the undamaged 100 m section above quickly moving its CoG >6 m eastward due to this east wall buckling. This can be also be seen on pictures/videos but then the whole section above disappears in smoke. This is very strange. You would expect that undamaged section to continue moving eastway and not disappear at fall. It should fall down to the ground and be damaged there.

There are many indications on the other hand that the global collapse was initiated/caused by control demolition by remote control and that the also the undamaged section above was blown up in the air by controlled demolition before hitting the ground.

The lack of forensic examination of the tower steel structure wreckage is frightening.

[Gravy]

Why didn't the upper part pivot about it's base? See Bazant & Zhou (2001) Appendix II (http://www.911-strike.com/BazantZhou.htm)

Frank Greening's paper on "Tipping (http://www.911myths.com/WTC2TIP.pdf)"

JREF juryjone with a simple graphic explanation of why the top of the south tower didn't fall to the side. (http://forums.randi.org/showpost.php?p=2243709&postcount=1243)

R. Mackey on Independent validations of the NIST report. (http://forums.randi.org/showpost.php?p=2547065&postcount=21)

[David Wong]

There are many indications on the other hand that the global collapse was initiated/caused by control demolition by remote control and that the also the undamaged section above was blown up in the air by controlled demolition before hitting the ground.


This person has no education in this subject. No way.

The technical stuff he's posted has to be copied and pasted from other websites. It's sprinkled with these ridiculous statements that I believe are the poster's own words peeking through.

[Panoply_Prefect]

Nothing.

Nothing? You claimed:


WTC2 was the first tower that collapsed. I assume the people trapped in the section above thought they were safe and that the tower would not collapse as the fire slowly went out. But then WCT2 suddenly collapsed (...)
The people trapped in the WCT1 must have been horrified when WTC2 collapsed. I assume they concluded their tower would also collapse ... and some desperate persons decided to jump before that, etc. Terrible.



And you were wrong. People jumped from WTC1 prior to the WTC2 collapse, and people from WTC2 jumped (prior to collapse obviously) as well. Which means your theory on why people jumped is debunked. It also shows just what level of respect you are willing to give those who took the horrible decision to actually jump from those buildings. That is not "nothing", but in the mind set on denial.

And the reply you gave to stateofgrace, did avoid his final question. One that I have been asking you a lot of times. See if you can face up now:


So in the spirit of fair play and open discussion why don't you tell me what happeend on 911, no more "I'm just asking questions", no more sliding out of it, a simple summary of the day events. It goes something like this.

" On 911 four planes were hijacked by Islamic terrorists, two hit the towers, which burnt and then fell down. They fell on top of other buildings , which also fell down. A third plane hit the Pentagon and the forth crashed after the passengers fought back. A Group called Al Qaeda have repeadley claimed responsibility for this attack"

Now that is a simple summary, please offer up your own, do not have a go at mine, after all I am just a sheep who buys into anything, so why don't you tell , in your own words what happened?

(my bolding)

Oh, and you forgot my two questions:


Do you believe that videos that show planes hit the Twin Towers are forged?

Do you believe that the witnesses who saw a plane hit the Pentagon are lying?


A simple "yes" or "no" will suffice.

Cheers,
SLOB

[Belz...]

Nothing. The topic raised by me is the NIST statements about WTC2 collapse. There is no evidence that global collapse ensued due to the alleged east wall buckling

No evidence ?

http://forums.randi.org/imagehosting/thum_608045892c4f64e35.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3266)

http://forums.randi.org/imagehosting/thum_608045892c65f25a4.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3267)

[Heiwa]

No evidence ?

http://forums.randi.org/imagehosting/thum_608045892c4f64e35.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3266)

http://forums.randi.org/imagehosting/thum_608045892c65f25a4.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3267)

Not really - the pictures show the building still standing with the east wall perimeter columns deformed a little inward.

[BillyRayValentine]

Nothing. The topic raised by me is the NIST statements about WTC2 collapse.

You also raised the issue of the fires being small and contained. And the heat being swept away by the breezes. And the people in WTC1 jumping NOT because they're skin was being seared by the heat, but because they were frightened by the collapse of WTC2.

If your only beef is with the NIST statements, then limit your comments to such. You'll still be ignorant and wrong, but far less offensive to us sentient beings.

[Heiwa]

Why didn't the upper part pivot about it's base? See Bazant & Zhou (2001) Appendix II (http://www.911-strike.com/BazantZhou.htm)

Frank Greening's paper on "Tipping (http://www.911myths.com/WTC2TIP.pdf)"

JREF juryjone with a simple graphic explanation of why the top of the south tower didn't fall to the side. (http://forums.randi.org/showpost.php?p=2243709&postcount=1243)

R. Mackey on Independent validations of the NIST report. (http://forums.randi.org/showpost.php?p=2547065&postcount=21)

With all due respect to Greening according NIST the undamaged upper section above the fire zone seems to have tilted 7-8° to east much quicker, i.e. in a very short time, because it has not even started to fall. Are we then to believe that it stopped tilting and fell straight down - causing a symmetrical collapse? It seems magic.

[Pardalis]

Not really - the pictures show the building still standing with the east wall perimeter columns deformed a little inward.

:hb:

[Heiwa]

You also raised the issue of the fires being small and contained. And the heat being swept away by the breezes. And the people in WTC1 jumping NOT because they're skin was being seared by the heat, but because they were frightened by the collapse of WTC2.

If your only beef is with the NIST statements, then limit your comments to such. You'll still be ignorant and wrong, but far less offensive to us sentient beings.

If you have some moral objections to me discussing the alleged 'facts' of NIST in order to reach some just conclusions, suggest you start another thread about that.

[stateofgrace]

Nothing.

It means nothing to you because like all good truthers you dismiss anything that proves you are utterly and completely wrong. It proves you are as dismissive as you are clueless. It proves you are a heartless individual who believes he as a grasp on reality when you have none. PEOPLE died, fool, they jumped to their deaths because of the intense heat inside the towers. This intense heat came from the fires. The fires you dismiss as irrelevant.

Maybe you could actually prove you are a human being and actually acknowledge you were wrong and made an inappropriate comment and apologies for being highly offensive.
The topic raised by me is the NIST statements about WTC2 collapse. There is no evidence that global collapse ensued due to the alleged east wall buckling i.w.o. the impact area causing load redistribution. There are pictures/videos showing the wall being deformed - none that it collapses causing load redistribution, etc. NIST suggests the core was softened, etc. but there is no evidence.
Wow how to totally contradict yourself in one easy move. the external columns buckled inwards, stop making up nonsense.
Then there is the NIST statement about the undamaged 100 m section above quickly moving its CoG >6 m eastward due to this east wall buckling. This can be also be seen on pictures/videos but then the whole section above disappears in smoke. This is very strange. You would expect that undamaged section to continue moving eastway and not disappear at fall. It should fall down to the ground and be damaged there.

There are many indications on the other hand that the global collapse was initiated/caused by control demolition by remote control and that the also the undamaged section above was blown up in the air by controlled demolition before hitting the ground.

The lack of forensic examination of the tower steel structure wreckage is frightening



Are you on something ? seriously ? Are you just making this up as you go along ? The top section was blown up in midair? Seriously ? This is a wind isn't it ? NOBODY can be serious with this one, please, please tell me you are just having a laugh here. It is not funny by the way , you do realise that people were still alive inside the top section of WTC 2 when it fell towards earth, you do realise that this top section contained real people, with real families and real thoughts and aspirations .



The lack of forensic examination of the tower steel structure wreckage is frightening.


I will tell you what is frightening sunbeam is your complete lack of understanding of anything and your complete lack of any moral fibre. You are lacking in so much it is actually mind boggling you can actually make it though the day. It is actually frightening to believe that somebody like you who claims to know what he is talking about can be so wrong in everything he says.

It is a worry that crackpots and loons who make it all up as they go along , actually believe they deserve to heard rather than simply dismissed as crackpots and loons, but hey I guess it goes with the internet where you are free to say what you like, irrespective of how disrespectful it is and irrespective of how completely and utterly insane it may sound.

[Heiwa]

It means nothing to you because like all good truthers you dismiss anything that proves you are utterly and completely wrong. It proves you are as dismissive as you are clueless. It proves you are a heartless individual who believes he as a grasp on reality when you have none. PEOPLE died, fool, they jumped to their deaths because of the intense heat inside the towers. This intense heat came from the fires. The fires you dismiss as irrelevant.

Maybe you could actually prove you are a human being and actually acknowledge you were wrong and made an inappropriate comment and apologies for being highly offensive.
.
Wow how to totally contradict yourself in one easy move. the external columns buckled inwards, stop making up nonsense.


Are you on something ? seriously ? Are you just making this up as you go along ? The top section was blown up in midair? Seriously ? This is a wind isn't it ? NOBODY can be serious with this one, please, please tell me you are just having a laugh here. It is not funny by the way , you do realise that people were still alive inside the top section of WTC 2 when it fell towards earth, you do realise that this top section contained real people, with real families and real thoughts and aspirations .




I will tell you what is frightening sunbeam is your complete lack of understanding of anything and your complete lack of any moral fibre. You are lacking in so much it is actually mind boggling you can actually make it though the day. It is actually frightening to believe that somebody like you who claims to know what he is talking about can be so wrong in everything he says.

It is a worry that crackpots and loons who make it all up as they go along , actually believe they deserve to heard rather than simply dismissed as crackpots and loons, but hey I guess it goes with the internet where you are free to say what you like, irrespective of how disrespectful it is and irrespective of how completely and utterly insane it may sound.

Moral and my alleged lack of any moral fibre is OT but I will reply anyway. The analysis of the scientific NIST report has nothing to with moral or lack of it. Many persons in this discussion ask me various specific questions what happened at 9/11 and why I do not answer. But I have. I have answered somebody and therefore everybody:

"If you have read the 9/11 Commission report about all events that took place on 9/11 prior impacts as I assume you have, do you believe everything in it? I do not (and millions others)."

Very soon after 9/11 the answer to all questions were given by the authorities (It was 19 arabs, etc). And it was added that if you didn't believe THAT, then you were worth nothing or part of some evil group. Moral? Of course - it is moral to believe authorities according to the same authorities. But it has nothing to do with justice and science.

Many years later the 9/11 Commission reported that the early findings of the authorities were 100% correct (It was 19 arabs, etc). What else could they report according to the present moral standards?

I fear that the NIST engineers were also influenced by the moral threats of the authorities and thus produced reports to suit. But, I repeat, it has nothing to do with justice and science.

Actually - to stand up for justice and science in the present situation requires moral fibre shown by prof. S. Jones & Co.

[Panoply_Prefect]

words


Do you believe that videos that show planes hit the Twin Towers are forged?

A simple "yes" or "no", will suffice.


Now that is a simple summary, please offer up your own, do not have a go at mine, after all I am just a sheep who buys into anything, so why don't you tell , in your own words what happened?


An as simple summary as stateofgrace's will suffice.

/S

[Heiwa]

Do you believe that videos that show planes hit the Twin Towers are forged?

A simple "yes" or "no", will suffice.

/S

Yes, I do not believe the 9/11 Commission report (as stated 10 minutes earlier).

[Gravy]

How many batpoo-crazy no-planers can this place hold? Don't they know about Rick Siegel's forum (http://911researchers.com/)? Every miserable misfit in Casablanca knows Rick's.

[T.A.M.]

How many batpoo-crazy no-planers can this place hold? Don't they know about Rick Siegel's forum (http://911researchers.com/)? Every miserable misfit in Casablanca knows Rick's.

Well if not Rick's, They'll always have Paris....

TAM;)

[Panoply_Prefect]

Yes, I do not believe the 9/11 Commission report (as stated 10 minutes earlier).

What does the 9/11 Commission report have to do with the various videorecordings of the planes hitting the Twin Towers?

But thanks for your straight "yes".

/S

[Heiwa]

What does the 9/11 Commission report have to do with the various videorecordings of the planes hitting the Twin Towers?

But thanks for your straight "yes".

/S

The 9/11 Commission report suggests that AA175 collided with WTC2. But I do not think anybody has been able to identify AA175 as that plane shown on various videos of the collision (the videos are too bad?). BTW - the original 'live' footages by several news media of the collision have later been edited to remove the 'Fade to Black' sign that pops up and various beeps in the live versions, etc. that some researchers suggest indicate live editing (!!), i.e. that the live show was delayed 17 seconds in order to 'paste in' a plane in the sky while the voice continues reporting no plane but an explosion, etc. http://www.livevideo.com/socialservice . Amazing observations.

It seems the 9/11 Commission just guessed that it was AA175 colliding with WTC2 and never considered, e.g. 'live editing' as a means to confuse the public?

Evidently no witness on the ground ever saw AA175 colliding with WTC2.

It is easy, in a confusion about high-jacked planes and collisions with towers, to assume that the planes collided with the towers but it has nothing to do with justice and science that require real evidence.

[Alferd_Packer]

So what hapened to the planes full of people, then?

What did the witnesses on the ground actually see?

What did the witnesses on the ground actually hear?



Give us your theory on what happened, we really do want to know.

edit

Evidently no witness on the ground ever saw AA175 colliding with WTC2

that is a very stupid statement.

[Heiwa]

I note that in above message #188 the link goes to part 6 of socialworkers analysis. See it - and then click on part 1 further down; Enjoy.

[stateofgrace]

The 9/11 Commission report suggests that AA175 collided with WTC2. But I do not think anybody has been able to identify AA175 as that plane shown on various videos of the collision (the videos are too bad?). BTW - the original 'live' footages by several news media of the collision have later been edited to remove the 'Fade to Black' sign that pops up and various beeps in the live versions, etc. that some researchers suggest indicate live editing (!!), i.e. that the live show was delayed 17 seconds in order to 'paste in' a plane in the sky while the voice continues reporting no plane but an explosion, etc. http://www.livevideo.com/socialservice . Amazing observations.

It seems the 9/11 Commission just guessed that it was AA175 colliding with WTC2 and never considered, e.g. 'live editing' as a means to confuse the public?

Evidently no witness on the ground ever saw AA175 colliding with WTC2.

It is easy, in a confusion about high-jacked planes and collisions with towers, to assume that the planes collided with the towers but it has nothing to do with justice and science that require real evidence.

Wow, just wow., I am speechless.

[Heiwa]

So what hapened to the planes full of people, then?

What did the witnesses on the ground actually see?

What did the witnesses on the ground actually hear?



Give us your theory on what happened, we really do want to know.

edit



that is a very stupid statement.

You haven't seen the info in the link then?

There is no evidence that AA175 is the plane on the video colliding with WTC2.

We do not know what happened to the people in AA175. They disappeared somewhere and are missing? Then ask FBI about them! FBI looks for for missing people.

What did people on the ground see? Nobody saw AA175. They saw something else. But didn't have a possibility knowing it was AA175.

What did people on the ground actually hear? Probably an explosion ... but not a plane approaching before that. Did the 9/11 Commission analyse the sound recordings? Apparently not.

What really happened? I have not got a clue. I am just a structural engineer in ship building happily far away from USA. If I hint at foul play about the WTC2 collapse that ensued I am accused of being amoral by some allegedly moral people. But it seems foul play was also involved prior to the collapse ... to fool all these moral people.

[Heiwa]

Wow, just wow., I am speechless.

So was also I at first. Spread the message.

[T.A.M.]

I don't think you want him to spread the message he was referring to when the "speechless" line was uttered to the screen.

TAM:)

[kookbreaker]

So was also I at first. Spread the message.

Sorry, but spreading that kind of insanity as a 'message' is like spreading the bubonic plague as a 'purification ritual'.

[Panoply_Prefect]

the original 'live' footages by several news media of the collision have later been edited to remove the 'Fade to Black' sign that pops up and various beeps in the live versions,


Yes, I seem to recall you claimed that even all the archived material at Wayback Machine has been edited prior to being uploaded, to remove that "fade to black" you seem to think, for some reason, indicates live realtime editing. You failed, however, to explain as to why while the clips from BBC, FOX5 and ABC had no Fade-to-black, CNN still had it. But, oh, its obvious. NWO slipped there didn't they, yeah, thats right.


etc. that some researchers suggest indicate live editing (!!), i.e.

Who but "Socialworker"?


Cheers,
SLOB

[Heiwa]

Sorry, but spreading that kind of insanity as a 'message' is like spreading the bubonic plague as a 'purification ritual'.

You are quite right even if OT. The US moral majority however needs a little shaking up. There is a real world outside Springfield.

[T.A.M.]

doh!!

Wait til I tells Cleatus...hes gonna be pissed. I told him, gosh darn it, that the world stops at dem der "springfield" town limit signs.

TAM;)

[Heiwa]

doh!!

Wait til I tells Cleatus...hes gonna be pissed. I told him, gosh darn it, that the world stops at dem der "springfield" town limit signs.

TAM;)

Sometimes some people at my coffee house wonder if the US cowboys see what's ahead of the ears of their horses.

[T.A.M.]

sometimes people at my coffee house wonder if CTists see anything that doesn't fit into their world view of the NWO and the 9/11 plot.

TAM;) (A Canadian Urbanite)

[kookbreaker]

Sometimes some people at my coffee house wonder if the US cowboys see what's ahead of the ears of their horses.

I'm always amused at statements like this, because the people who make them invariably turn around and call Americans arrogant.

[Panoply_Prefect]

You are quite right even if OT. The US moral majority however needs a little shaking up. There is a real world outside Springfield.

You, however aren't really shaking up the "US moral majority", but pissing on the victims of 911 and their living relatives.

But you wouldn't know the difference, from your desktop warrior pad way over in France.

/S

[Crungy]

There are many indications on the other hand that the global collapse was initiated/caused by control demolition by remote control and that the also the undamaged section above was blown up in the air by controlled demolition before hitting the ground.


Yup, somehow these many "indications" have escaped the worlds leading structural engineers, but the batSh**t paranoid nutters all declare it blindingly obvious.



The lack of forensic examination of the tower steel structure wreckage is frightening.

Not nearly as frightening as your complete detachment from reality.

Heiwa is just Swedish for Ace Baker.

[T.A.M.]

How the F&*K can you blow up a 20 storey piece of building, in mid air, as it is falling to earth, through controlled demolition...lol

Please Heiwa, give us at least a bare bones description of how they did that one...that one is almost as good as the no-planer's Star Wars Weaponry...

TAM:)

[Heiwa]

How the F&*K can you blow up a 20 storey piece of building, in mid air, as it is falling to earth, through controlled demolition...lol

Please Heiwa, give us at least a bare bones description of how they did that one...that one is almost as good as the no-planer's Star Wars Weaponry...

TAM:)

Sorry cannot answer. My US sources seem to have disappeared.

http://www.globalresearch.ca/index.php?context=va&aid=6377

[T.A.M.]

I don't want sources for this, I want you, as an "Engineer" to describe to me, how they blew up the twenty story top section of the WTC AS IT WAS FALLING TO EARTH via CD?

TAM:)

[Pardalis]

This reminds me of geggy's "controlled demolition made to look like a fake collapse but which was in fact a real collapse in part because it looks so much like one" theory.

Truthers trying to conciliate their CD theory with the overwhelming evidence that the towers fell by structural collapse... What a pathetic sight.

[Heiwa]

I don't want sources for this, I want you, as an "Engineer" to describe to me, how they blew up the twenty story top section of the WTC AS IT WAS FALLING TO EARTH via CD?

TAM:)

Pls read first the link. Second, I am glad that you agree that they blew up the top section and now wonder how. I assume they did it it by remote control. Like the rest of the tower. BTW, who are they you are referring to?

[Heiwa]

You, however aren't really shaking up the "US moral majority", but pissing on the victims of 911 and their living relatives.

But you wouldn't know the difference, from your desktop warrior pad way over in France.

/S

OT and moral rubbish. Start to think, SLOB.

[T.A.M.]

Fire proof detonation charges that survived an airplane impact, intense multistorey fires, and the collapse of the building below it. A seperate detonation circuit just for the top portion...so the airplane had to be dead on, or the wiring for the detonation for the top portion would have been severed.

Come on man...admit you don't really believe that shaite do you...REALLY (cue south park character).

TAM:)

[T.A.M.]

Pls read first the link. Second, I am glad that you agree that they blew up the top section and now wonder how. I assume they did it it by remote control. Like the rest of the tower. BTW, who are they you are referring to?

I agreed to nothing. I am asking you to explain your theory on how they did this. I find your suggestion that they blew up the top section seperately, as it was falling, to be more insane than most of the no-planer CGI fakery crap...and that is saying something.

Its called "playing along" to hear your further explanation.

TAM:)

[T.A.M.]

your link is OT with respect to the top portion being detonated independently.

TAM:)

[Pardalis]

http://forums.randi.org/showpost.php?p=1624347&postcount=3105

I'm saying it didn't look like a controlled demo that is normally practiced in a regular building imploding project

I'm saying it (controlled demo) was done differently and uniquely for the towers to start imploding from the top

Strangely reminiscent isn't it? And geggy is no engineer of anykind.

[Panoply_Prefect]

Start to think, SLOB.

Yes. I. Will. Here. Is. My. Theory:

Fire bad.

Now, for the question you've so far dodged:


Now that is a simple summary, please offer up your own, do not have a go at mine, after all I am just a sheep who buys into anything, so why don't you tell , in your own words what happened?


An as simple summary as stateofgrace's will suffice.

/S

[Heiwa]

I agreed to nothing. I am asking you to explain your theory on how they did this. I find your suggestion that they blew up the top section seperately, as it was falling, to be more insane than most of the no-planer CGI fakery crap...and that is saying something.

Its called "playing along" to hear your further explanation.

TAM:)

Strange developments of this discussion about the WTC2 collapse that could not take place according to NIST descriptions (the subject). Suggest you start a new thread how they did it. My US sources seems to have disappeared as per some emergency instructions. Do you care about that?

[T.A.M.]

Strange developments of this discussion about the WTC2 collapse that could not take place according to NIST descriptions (the subject). Suggest you start a new thread how they did it. My US sources seems to have disappeared as per some emergency instructions. Do you care about that?

You are the one who made the statement that they (whoever you feel they are...NWO, USG, whatever) blew up the top section of the WTC via remote control, after it had begun falling toward the ground.

You posited the question, dont then tell me to start a new thread on it...answer the question, provide us with your engineering education behind you, on how they carried this out...or else dodge it again like a coward.

I hope no harm have come to your sources, whomever they are, but no I really do not care that they have "mysteriously" disappeared.


TAM:)

[Heiwa]

Yes. I. Will. Here. Is. My. Theory:

Fire bad.


/S

Make a better effort. Or try at least.

[kookbreaker]

Make a better effort. Or try at least.

Its a perfectly viable, if simplified theory. There's really nothing wrong with it, and all the evidence points to that.

Wheras all you have done is try to claim TAM was agreeing with something he was not, a cheap debating trick if I have ever seen one.

Anyone else starting to smell :socks:?

[Heiwa]

You are the one who made the statement that they (whoever you feel they are...NWO, USG, whatever) blew up the top section of the WTC via remote control, after it had begun falling toward the ground.

You posited the question, dont then tell me to start a new thread on it...answer the question, provide us with your engineering education behind you, on how they carried this out...or else dodge it again like a coward.

I hope no harm have come to your sources, whomever they are, but no I really do not care that they have "mysteriously" disappeared.


TAM:)

What was wrong with the previous answer? Remote control. For details - sorry - my US advisors cannot be reached. Apparently a result of http://www.whitehouse.gov/news/releases/2007/07/20070717-3.html .

I think it is better we stop this discussion here. You have all proven you cannot see beyond the tall ears of your donkeys. Bye, bye.

[Panoply_Prefect]

Make a better effort. Or try at least.

Ok, I agree with the theory summarized by stateofgrace.

How about you?

/S

[T.A.M.]

I'd say don't let your tail get caught in the door on the way out, but it is far between your legs, so there is no chance...bye bye.

TAM:)

[T.A.M.]

Its a perfectly viable, if simplified theory. There's really nothing wrong with it, and all the evidence points to that.

Wheras all you have done is try to claim TAM was agreeing with something he was not, a cheap debating trick if I have ever seen one.

Anyone else starting to smell :socks:?

This guy comes here claiming to be an engineer, yet even after repeated requests to explain how a falling 20 storey building section could be remotely detonated via CD, while FALLING TO EARTH, he gets on with his "US advisor" bullcrap, and say that "remote control" is all he can provide as an explanation.

Sock...ya, or fake, either works for me.

TAM:)

[Jonnyclueless]

This guy comes here claiming to be an engineer, yet even after repeated requests to explain how a falling 20 storey building section could be remotely detonated via CD, while FALLING TO EARTH, he gets on with his "US advisor" bullcrap, and say that "remote control" is all he can provide as an explanation.

Sock...ya, or fake, either works for me.

TAM:)


I don't want to make any false implications or anything. But I am starting to think that maybe he isn't an engineer after all. Just putting it out there in case it hasn't been considered....

[T.A.M.]

I agree. He has shown no proof he is an engineer, either in the complexity/relavence of his answers, or any documentation.

Any engineer, who when asked "how would they cause a remote CD in the top portion of the tower, once it had begun falling", simply says "Remote Control" displays none of the intellect or logic that one would hope would come from someone smart enough to complete an engineering degree.

TAM:)

[Panoply_Prefect]

EDIT: Forgetit

[T.A.M.]

I would imagine he has retreated to go read some more of the details that some CTer created on this "Remotely CDed WTC top section" theory. He will be back in a while, all refreshed, ready to give us some more garbage.

TAM:)

[uk_dave]

Strange developments of this discussion about the WTC2 collapse that could not take place according to NIST descriptions (the subject). Suggest you start a new thread how they did it. My US sources seems to have disappeared as per some emergency instructions. Do you care about that?

I see a large dose of Lithium in your future.

[twinstead]

Wow. Our government is bad enough without folks like Heiwa getting all paranoid and pathological about it.

[Rahne Everson]

What was wrong with the previous answer? Remote control. For details - sorry - my US advisors cannot be reached. Apparently a result of http://www.whitehouse.gov/news/releases/2007/07/20070717-3.html .

I think it is better we stop this discussion here. You have all proven you cannot see beyond the tall ears of your donkeys. Bye, bye.

So... your sources were causing instability in Iraq?

[David Wong]

So this guy is full-blown. Towers rigged with many tons of explosives, with nobody noticing, planes switched, every news outlet in on it, thousands of witnesses fooled...

Wow. The cream of the CT crop here.

[T.A.M.]

even better, he claims...lol...get this, he claims that once the WTC started to collapse, that the NWO had the top part, the 20 storey section of the building above the impact zone, colapse via seperate CD for that section alone, WHILE IT WAS FALLING TO EARTH.

TAM:)

[Corsair 115]

What was wrong with the previous answer? Remote control.You do understand the technical definition of remote control, don't you? It means an object which is controlled remotely by a human operator, like how an RC model aircraft is controlled by human standing on the ground watching the model while it flies. That's remote controlled.

Something like a Tomahawk cruise missile is NOT remote controlled. It is programmed with a pre-set course before it is launched, then follows that course autonomously - no more human input needed. Which means if something goes wrong with the missile's guidance system it misses the target.

At least get the terminology correct. So were the 9/11 jets remote controlled or following pre-programmed courses autonomously?

[stateofgrace]

You do understand the technical definition of remote control, don't you? It means an object which is controlled remotely by a human operator, like how an RC model aircraft is controlled by human standing on the ground watching the model while it flies. That's remote controlled.

Something like a Tomahawk cruise missile is NOT remote controlled. It is programmed with a pre-set course before it is launched, then follows that course autonomously - no more human input needed. Which means if something goes wrong with the missile's guidance system it misses the target.

At least get the terminology correct. So were the 9/11 jets remote controlled or following pre-programmed courses autonomously?

This could be a mistake, Corsair, I don't think he understands anything, just thought I would say.

[Belz...]

Not really - the pictures show the building still standing with the east wall perimeter columns deformed a little inward.

A little ?

http://forums.randi.org/imagehosting/thum_608045892c65f25a4.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=3267)

[Belz...]

The 9/11 Commission report suggests that AA175 collided with WTC2. But I do not think anybody has been able to identify AA175 as that plane shown on various videos of the collision

Yeah, it's kinda hard to read numbers of a plane going that fast from that distance.

the original 'live' footages by several news media of the collision have later been edited to remove the 'Fade to Black' sign that pops up and various beeps in the live versions, etc. that some researchers suggest indicate live editing (!!)

Evidence ?

, i.e. that the live show was delayed 17 seconds in order to 'paste in' a plane in the sky while the voice continues reporting no plane but an explosion, etc.

That's Ace Baker's theory. And he's nuts.

it has nothing to do with justice and science that require real evidence.

If by "real evidence" you mean "absolute proof" you're bound to be dissapointed.

[Belz...]

Sorry cannot answer.

I don't doubt it.

My US sources seems to have disappeared as per some emergency instructions.

Your sources are no longer available. It doesn't follow that they were "silenced".

Remote control.

Sorry, that's not good enough.

How CAN you detonate a 20+ storey building in mid-air ?

Why would you want to ?

[kookbreaker]

So...yet ANOTHER troofer who lies about his qualifications and turns out to not be what claims, or even close.

Y'know, if any of us so much as exagerrated their job desccription we would never hear the end of it from the troofer side, yet their end of the pole lies and lies and lies and lies and lies abot their qualifications and nary a word is said.

Hypocrisy, thy name is the Truth Movement.

[Alferd_Packer]

Can I be the first to call you a B.S. artist?


What took you guys so long?

I had him pegged all the way back on page 2. :D

[Lurker]

I assume that the perimeter columns are not affected by heat as they are outside the fire. I also assume the core columns are not affected by the heat (because it it unclear how hot it was at the various columns). NIST suggests that the floors sags due to heat and this I can model in different ways as long as the boundary conditions remain unchanged, i.e. the floors are connected to the columns. I can manually change the truss material properties. The vertical load on the trusses is small so sagging is small. The model is still stable. I can also model what happens if some trusses cool down again. The situation improves.

I am not sure either of your assumptions here (preimeter columns and core unaffected by heat) are valid. In the heat transfer analysis the temp of the perimeter columns does not equal the outside air temp. Convection is just not that efficient. As to the core, I think it is fairly safe to assume that those columns are also not at room temperature.


But if the floors starts to detach from the columns due heat + sagging I cannot model that because I have no idea if, where and how it takes place. Everything becomes guesswork. But why would the trusses be ripped of the columns due fire long after the impact?
One might have to model the welds or bolted connections on the beams. Add in expansion due to heat. As to the time parameter, it could be heat transfer effects (which have a time component) or stress relaxation which also has a time component and is greatly effected by temperature. Also, all beams are not loaded equally after the impact so some may heva higher loads than others and fail at different times, thus the time factor again shows up.


I can remove the perimeter columns of the east wall (assumed buckled and not connected to the Trusses/floors) and observe the load re-distribution. The weight of the intact section above is shifted to the remaining walls and the core and the model still stands. No global collapse ensues. There was plenty of redundancy, it appears.

And you have performed the FEA showing this or are you just making educated guesses?

Lurker

[Mr. Skinny]

You do understand the technical definition of remote control, don't you? It means an object which is controlled remotely by a human operator, like how an RC model aircraft is controlled by human standing on the ground watching the model while it flies. That's remote controlled.

Something like a Tomahawk cruise missile is NOT remote controlled. It is programmed with a pre-set course before it is launched, then follows that course autonomously - no more human input needed. Which means if something goes wrong with the missile's guidance system it misses the target.

At least get the terminology correct. So were the 9/11 jets remote controlled or following pre-programmed courses autonomously?

Not to put too fine a point on this, Corsair, but some RC aircraft can be flown by either human or autonomous control. They can be flown by human control and then switched to follow pre-planned waypoints sent from the ground control station. If it loses contact with the ground station, it can have an on-board program to cause it to fly to a waypoint within range of the station, or even auto-land itself.

These aircraft are still considered to be Remote Control aircraft, even when there is no human-in-the-loop. So your correction of Heiwa is not 100% accurate. :)

[T.A.M.]

technically, Heiwa has not proven he is an engineer, but nor has it been proven he is not. I am merely speculating that he is not based on his running from this thread when the tough questions were asked, and his lack of knowledge etc...in his posts...

TAM:)

[Heiwa]

I am not sure either of your assumptions here (preimeter columns and core unaffected by heat) are valid. In the heat transfer analysis the temp of the perimeter columns does not equal the outside air temp. Convection is just not that efficient. As to the core, I think it is fairly safe to assume that those columns are also not at room temperature.


One might have to model the welds or bolted connections on the beams. Add in expansion due to heat. As to the time parameter, it could be heat transfer effects (which have a time component) or stress relaxation which also has a time component and is greatly effected by temperature. Also, all beams are not loaded equally after the impact so some may heva higher loads than others and fail at different times, thus the time factor again shows up.



And you have performed the FEA showing this or are you just making educated guesses?

Lurker

Re heat I assume it is <600°C locally and <300°C generally so it would not affect the material properties too much; the heat will assist deformation.

One difficulty is to model the floor trusses. The lower flange is a steel bar, the 'web' is also steel bars, but the upper flange is a steel plate + concrete poured on it. Thus the upper flange sandwich of the trusses is quite strong and if it it continuously connected to the perimeter and core walls/columns all around, it can hardly detach due to heat. So the floors may deform - sag - when the lower flange heats up (the span is quite long) but even so it is unlikely that the connections to the walls will burst and then the floors would still support the columns = no collapse.

The floor sag is also limited to the free height of the floors, i.e. new support/contact points will develop.

I use a CASA Gifts software of limited capability just to get a feel of the problem. According my opinion the heat could contribute to local deformations, e.g. the east wall, but hardly to global collapse.

[Gravy]

One difficulty is to model the floor trusses. The lower flange is a steel bar, the 'web' is also steel bars, but the upper flange is a steel plate + concrete poured on it. Thus the upper flange sandwich of the trusses is quite strong and if it it continuously connected to the perimeter and core walls/columns all around, it can hardly detach due to heat. So the floors may deform - sag - when the lower flange heats up (the span is quite long) but even so it is unlikely that the connections to the walls will burst and then the floors would still support the columns = no collapse.

Since you came back, I'll also come back.

Heiwa. Pay close attention.

You
still
have
no
idea
what
NIST's
explanation
of
the
collapses
is.

Since you refuse to read the NIST reports, will you at least take a few goddamned minutes and read their short "Answers to frequently asked questions?" (http://tinyurl.com/pqrxt)

Will you?

Jesus Christ, what deliberately ignorant children the 9/11 deniers are.

[Belz...]

Re heat I assume it is <600°C locally and <300°C generally so it would not affect the material properties too much; the heat will assist deformation.

Why stop there ? Why not simply assume it's room temperature ?

[Lurker]

Re heat I assume it is <600°C locally and <300°C generally so it would not affect the material properties too much; the heat will assist deformation.

Well, there is one of your first problems there. You need more precise answers than this to actually perform the heat trasnfer analysis. To know the temperature distribution in the WTC, clearly the outer members would either be at a known temp or at a calculated temp from the FEA. The fact that you have no idea reveals that you did not perform an FEA of the structure. Or at least, not a coupled heat transfer/strucural analysis.

... but even so it is unlikely that the connections to the walls will burst and then the floors would still support the columns = no collapse.
I am not sure people are claiming the connections burst but that the floors pulled the outer walls in which reduced the structural capacity of those columns.


I use a CASA Gifts software of limited capability just to get a feel of the problem. According my opinion the heat could contribute to local deformations, e.g. the east wall, but hardly to global collapse.

The question is whether the combination of heat AND loss of structural integrity due to the plane crash was enough to cause the collape. Your opinion is noted but I see you have failed to back it up with anything more than continued opinion. Why not put your FEA model up on a FTP site so we can take a look?

Lurker

[Lurker]

Heiwa:

I will make a simple analogy of what happened. (Correct me if I am wrong)

1. Imagine a floor is held up by 80 columns.

2. A plane hits them and takes out ro severely damages 25 of them. Many remaining columns have the fireproofing damaged and/or removed from the impact.

3. The load of each remaining column increases by a minimum of 45% as the load redistributes to the remaining columns (we ignore bending forces, eccentrically loaded columns, and assume the load is distributed evenly which it would not be)

4. As the fires rage on, the temperature rises. Since every engineer knows that the modulus is a function of temperature, the strength of the materials is reduced dramatically. Also, steel and concrete elongate under the high temperature.

5. Floors sag, bending columns further reducing the structural capacity.

5. At some point, enough columns fail such that there is catastrophic and complete failure. Steel fails very quickly, it is not a ductile failure.

Hope this helps you plot out the theory.

Lurker

[Heiwa]

Well, there is one of your first problems there. You need more precise answers than this to actually perform the heat trasnfer analysis. To know the temperature distribution in the WTC, clearly the outer members would either be at a known temp or at a calculated temp from the FEA. The fact that you have no idea reveals that you did not perform an FEA of the structure. Or at least, not a coupled heat transfer/strucural analysis.


I am not sure people are claiming the connections burst but that the floors pulled the outer walls in which reduced the structural capacity of those columns.



The question is whether the combination of heat AND loss of structural integrity due to the plane crash was enough to cause the collape. Your opinion is noted but I see you have failed to back it up with anything more than continued opinion. Why not put your FEA model up on a FTP site so we can take a look?

Lurker

I am not doing a heat transfer analysis. I am doing a simple structural analysis at a given time with certain assumptions of the parts/members, which is only valid given the input being valid.

In my view - the floor/truss with it continuous top flange (thin steel plate/concrete) connected to the walls is very strong even when sagging. All the trusses are connected via the top flange.

Somebody asked me if I had read the NIST reports. I skimmed the first parts and concentrated on section 1-6D about the structural analysis. Unfortunately there are five authors so you do not know who has done/written what. So if you ask they can always refer to another.

Better would have been to ask one person only to analyze WTC1 and another WTC2. Now five persons analyse two different accidents and it becomes messy, e.g. fig. 5-3 on p 315. The writers mix up the two towers!

Re temperatures inside the WTC2, e.g. fig A-10, p. 342 is quite good. The core pillars are quite cool! And the perimeter columns are in fresh air so should also be cool! Max heat is apparently in the northeast corner on floor 82, etc. and you wonder why? It is not clear from any photos, etc. I doubt very much that info. How did they establish it?

The floor/truss connections to the columns are very simple. They cannot transfer any bending! Only axial forces. So even if the floor is sagging it transfers axial forces, etc. It is suggested that the sagging floor pulls in the perimeter columns but I doubt that. The vertical load on the floor is too small (20 kgs/m²). No way that a locally sagging floor will pull in all the perimeter columns. Etc. ,etc.

[Heiwa]

Heiwa:

I will make a simple analogy of what happened. (Correct me if I am wrong)

1. Imagine a floor is held up by 80 columns.

2. A plane hits them and takes out ro severely damages 25 of them. Many remaining columns have the fireproofing damaged and/or removed from the impact.

3. The load of each remaining column increases by a minimum of 45% as the load redistributes to the remaining columns (we ignore bending forces, eccentrically loaded columns, and assume the load is distributed evenly which it would not be)

4. As the fires rage on, the temperature rises. Since every engineer knows that the modulus is a function of temperature, the strength of the materials is reduced dramatically. Also, steel and concrete elongate under the high temperature.

5. Floors sag, bending columns further reducing the structural capacity.

5. At some point, enough columns fail such that there is catastrophic and complete failure. Steel fails very quickly, it is not a ductile failure.

Hope this helps you plot out the theory.

Lurker

I like simplifications.

1. Say it is 360 perimeter columns and 47 core columns that hold up a floor. The columns are interconnected at the floor by some horizontal bracing.

2. A plane hits them and damages 40 perimeter columns on the south side and 2 perimeter columns on the north side. All windows are blown out.

3. The load on the remaining columns increases marginally and the structure stands.

4. The temperature rises inside the building due to fire

5. The floor sags due heat. But the load on the floor is minimal (20 kgs/m²) and its own weight very small too and its connection to the column is very simple - it can only transfer axial loads but no bending moments.

5a. The axial load of the floor pulling the perimeter column inward is negligible. The perimeter column would not deform due to that.

5b. The fire/heat is getting smaller.

6. So no remaining perimeter column will suddenly fail.

[The Almond]

I like simplifications.

1. Say it is 360 perimeter columns and 47 core columns that hold up a floor. The columns are interconnected at the floor by some horizontal bracing.

2. A plane hits them and damages 40 perimeter columns on the south side and 2 perimeter columns on the north side. All windows are blown out.

I can agree with 1 and 2.

3. The load on the remaining columns increases marginally and the structure stands.

The load on the remaining columns increases by 25% in WTC1 (east and west walls) and 24% in WTC 2 (east wall). The load on the core decreases because the remaining top sections cause an eccentric loading.

4. The temperature rises inside the building due to fire

Changing the modulus of elasticity of the columns affected by the heat, thereby inducing plastic creep and strain deformations.

5. The floor sags due heat. But the load on the floor is minimal (20 kgs/m²) and its own weight very small too and its connection to the column is very simple - it can only transfer axial loads but no bending moments.

I was wondering where this floor load value came from. 20 kg/m^2 sounds way too low for a furniture load. The lightweight concrete in the floor was 120 lb/sq ft which translates to about 600 kg/m^2. At a depth of 5 inches, that's a floor weight of 76.2 kg/m.

5a. The axial load of the floor pulling the perimeter column inward is negligible. The perimeter column would not deform due to that.

The pull in forces, as described by NIST were 5 kips for WTC1. At elevated temperatures, this is quite sufficient to cause bowing of the exterior columns as shown in the photographic evidence.

5b. The fire/heat is getting smaller.

Irrelevant. What is at issue are the temperatures of the steel columns, the loads and the pull in forces, not the change in heat.

6. So no remaining perimeter column will suddenly fail.
These 6 points are an exceedingly poor example of an engineering analysis.

[Heiwa]

I can agree with 1 and 2.

The load on the remaining columns increases by 25% in WTC1 (east and west walls) and 24% in WTC 2 (east wall). The load on the core decreases because the remaining top sections cause an eccentric loading.

Changing the modulus of elasticity of the columns affected by the heat, thereby inducing plastic creep and strain deformations.

I was wondering where this floor load value came from. 20 kg/m^2 sounds way too low for a furniture load. The lightweight concrete in the floor was 120 lb/sq ft which translates to about 600 kg/m^2. At a depth of 5 inches, that's a floor weight of 76.2 kg/m.

The pull in forces, as described by NIST were 5 kips for WTC1. At elevated temperatures, this is quite sufficient to cause bowing of the exterior columns as shown in the photographic evidence.

Irrelevant. What is at issue are the temperatures of the steel columns, the loads and the pull in forces, not the change in heat.

These 6 points are an exceedingly poor example of an engineering analysis.

Thanks for agreeing with 1 and 2.

But then you are wrong.

Due to the design of the floor connections to the perimeter and core columns, the floors cannot transfer any vertical loads from the perimeter columns to the core columns during any alleged load re-distribution due to heating the floors! What does this mean for WTC2?

According NIST the east wall buckled at the damaged floors around floor 82 and there was load redistribution, i.e. the weight of the undamaged section above carried by the east wall was transferred to the north and south walls and the core columns.

However - no load could be transferred from the perimeter columns to the core via the floors. The trusses cannot transfer any big loads as shear and will not participate in the load re-distribution! (The only load on the floor truss transferred to the columns as shear is the weight of furniture, etc. (20 kgs/m² according NIST) on the truss and its own weight through a very small connection ot the truss to the column.

The load on the east wall can only be transferred to the north and south walls via the horizontal bracings keeping the perimeter together sideways at every floor. Either they manage to do that or they shear off ... like the floor connections of the east wall ... and the whole east wall above the buckled section would fall down to the ground! The east wall below the damaged section and the whole tower below the damaged section would stand.

Maybe some parts of the north and south walls would also fall down, but the west wall and the core evidently should stand! Quite basic, actually. That's why no steel skyscraper has ever globally collapsed. Local collapse of some areas for various reasons, yes.

Compare the building in Oklahoma city, where a home made bomb removed the perimeter columns of the front wall at ground level! The whole front wall fell down ... but the remainder of the building remained standing. Reason - the floors did not re-distribute load to the other side of the building.

So the NIST proposal (without any evidence) that global collapse of the whole tower ensues when the east wall first buckles and then collapses is wrong. Only the east wall above the damaged east wall section would fall down, i.e. only a local collapse would occur. The core and the west wall should be standing and probably most of the south and north walls. And the whole tower below the damaged floors.

All proposals of the heat weaking the structure all around and the core in the damaged area is just nonsense to confuse local collapse with global collapse.

NIST should be asked why not only local collapse ensued due to some local failures, i.e. only the east wall above the damaged area falling down.

But local collapse did not ensue. Suddenly the whole building explodes from the damaged area down to the bottom. What we see on all videos is not global collapse ... that should take much longer time ... but controlled demolition. No doubt about it.