Layman's terms please! Tower collapse issue

[Newtons Bit]

How do your "nation awards" make up for your inability to understand basic physics?

Hey remember when you said this:

Perhaps we should consider appling Euler to entire WTC twin towers, they are certainly long and skinny.

Or how about: this:

According to this, k = 2 for the free standing WTC towers and 0.5 for columns members:

This one is hilarious:

Here, Newtons Bit makes a calculation that any structural engineer should frankly be ashamed of. Instead of treating the WTC towers as interconnected structure of 240 perimeter columns and 47 core columns, he treats the columns as if they were independent of one another. Then he merely tries to sum their resistance to bending together. This is a gross error because the radius of gyration varies with both the cross-sectional area of the towers and their moment of inertia. Because the moment of inertia varies with depth and square of the width of the towers, we can see how extreme Newtons Bit's error is.

HILARIOUS. You can't even figure out how columns behave in a building and you're accusing someone else of have an inability in physics? Architect may be not an engineer, but he's certainly more qualified then you. Remember son, you're talking to professionals. We don't have to look up concepts on wikipedia or type them into Google because we don't know what other people are talking about when they say things like "shear, moment, moment of inertia, radius of gyration, shear flow, etc". We learned those things in school, we still have our textbooks on these subjects. Some of us even get paid to use them on a daily basis.

 

[Heiwa]

Even if it telescopes into itself and disintegrates, as you put it, the mass will still be there. All 33,000 tons of it.

Furthermore, because it has telescoped into itself and disintegrated, the load path of that mass will no longer be transmitted to the columns, now, will it?



Once again, I ask you: Under your theory, if the 33,000 ton mass of the upper block was no longer supported by the columns, then how would the lower block have supported it as you claim that it should have? How would this structure been able to withstand the dynamic load of the falling mass?

Nobody suggests that the mass goes missing. But it breaks up. It is not solid. It is a mess. Disorder. And such a mess cannot impact anything instantaneously. And not cause any global collapse because PE>SE. Gravity does not work like that. Most PE will just be deflected by solid structure and pushed to the side. That's why steel structure scyscrapers, etc. do not fall down like houses of cards.

My theory? Nist, Basant, Seffen, Spoof & Co suggest that the upper block was no longer supported by the columns at the impact/initiation zone ... and free falls, PE becomes KE, and impacts instantaneously the lower, intact structure. And that the upper block then remains intact and aligned with the lower structure all the time and produces global collapse chopping the columns below in pieces - like spaghetti. Nonsense of course.

My theory is just the opposite. The upper block, or what remains of it 3 seconds after the roof started to drop, is still connected to the structure, iwo the impact/initiation zone. Local collapses started far above the impact/initiation zone before anything else happened down below. The upper block disintegrates before destruction of the lower structure started. There is no free fall and no impact ... and no gravity driven collapse. What you see is some advanced type of CD.

 

[Heiwa]

No, don't squirm away. Don't dodge. It's right there. You said that the columns would "miss" on two whole walls. That they would slide off. How can they do that if the collapse initiation results in the one whole wall being pulled inwards and the tower rotating into that void? They didn't miss on the outside, the missed on the INSIDE. Like this:
[qimg]http://www.internationalskeptics.com/forums/imagehosting/thum_1632947dbe85f60a84.jpg[/qimg]
Or like this:
[qimg]http://www.waarheid911.nl/wtc2collapse.jpg[/qimg]

The columns did not just magically move over a foot, like you claim. They obvious fell inside the building due to the rotation, not outside. Do you want to retract this claim? Man up to something.

I asked you to provide actual calculations, not the inaccurate little childish things you do on your "paper". I've read it, I posted criticisms of it, and then you called me a fraud and a charlatan because I didn't agree with you. Remember that? Do you want to respond to my criticisms are shall we just let it stand that your paper is complete b.s.?

Now then, are you actually going to do something real, or you going to keep squirming away and dodging serious questions? I've already shown that the PE is far greater than the strain energy of the towers. But if you think otherwise, show us with man. Come now, there's a lot of people here who can understand this. Don't be shy, do some math for us. Show us your theory based on engineering principles, not ridiculous metaphors to beds or fish tanks. But remember, I get paid to design buildings so they won't fall down. I'm going to look at what you say carefully.

Nice picture of WTC2 that proves my point 100%. No alignment at all of upper block with lower intact structure. No free fall, no impact columns against columns. What you see on the photo is part of an unusual CD of WTC2. A second later the upper block disintegrates completely ... no load acting on it so you should wonder why! ... and long before it hits the ground. Where did the upper block of WTC2 go? It is supposed to drive the global collapse of the lower structure by falling straight down on it; impacts, crush front, etc.

Read my article, the math is not too difficult, it is peer reviewed but have a try to find something wrong. Just copy/paste the erroneous part.

As a test I have hidden one minor error in my article.

 

[rwguinn]

Is he winning his argument with himself yet?

 

[X]

What you see is some advanced type of CD.

And we're back to controlled demolition.

You know what? I'm not going to argue about all the evidence against a CD. The evidence which should be present, but isn't.
No. Forget about that.

Instead, I want you to answer one simple question, which I feel poses perhaps the biggest problem to controlled-demolition theorists.

Where do you think "they" found a company/organization willing to secretly rig the towers for demolition knowing full well that the collapse was going to kill thousands of people?

Where do you find a compay to do that? By your theory, whatever group did it must have done it in secrecy, leaving no signs of demolition devices, and every single member of that group had to remain silent during the entire set up, and after if they weren't silenced. A lot of people had to reamin silent about knowing fulll well that their actions would result in untold innocent deaths.

Where do you find a company capable of doing such a heinous thing to their own countrymen?

If you can't answer that, everything else is pointless, including erroneous speculation (oft corrected to no avail) about how the towers were constructed and fell.




ETA: I apologize if this is off-topic. Mods: Please split this if it is inappropriate to the thread.

 

[Architect]

How do your "nation awards" make up for your inability to understand basic physics?

Don't make me laugh. Spelling error aside, the challenge stands. I've got a Civic Trust award for my work on tall buildings, and I'll prove it to the Mods. You and your little shipbuilding chum can either accept the challenge, or quit claiming that we're greenhorns.

Come on, put up or shut up.

 

[Dave Rogers]

How do your "nation awards" make up for your inability to understand basic physics?

Hey, Bofors, remember when you claimed that the Second Law of Thermodynamics stated that a high symmetry state couldn't evolve spontaneously from a low symmetry state, and I pointed out that you'd just effectively claimed that crystal growth from a solution was impossible? What did that say about your ability to understand basic physics?

Dave

 

[Heiwa]

And we're back to controlled demolition.

You know what? I'm not going to argue about all the evidence against a CD. The evidence which should be present, but isn't.
No. Forget about that.

Instead, I want you to answer one simple question, which I feel poses perhaps the biggest problem to controlled-demolition theorists.

Where do you think "they" found a company/organization willing to secretly rig the towers for demolition knowing full well that the collapse was going to kill thousands of people?

Where do you find a compay to do that? By your theory, whatever group did it must have done it in secrecy, leaving no signs of demolition devices, and every single member of that group had to remain silent during the entire set up, and after if they weren't silenced. A lot of people had to reamin silent about knowing fulll well that their actions would result in untold innocent deaths.

Where do you find a company capable of doing such a heinous thing to their own countrymen?

If you can't answer that, everything else is pointless, including erroneous speculation (oft corrected to no avail) about how the towers were constructed and fell.




ETA: I apologize if this is off-topic. Mods: Please split this if it is inappropriate to the thread.

Well, if gravity alone could not do the job, what happened? I only demonstrate in my article, in layman's terms, that WTC1,2 were not gravity driven collapses. Too little PE available and the PE/KE is not applied on the structure below, actually the PE/KE (the upper block) disappears before initiation at WTC1, and has tilted so far outside WTC2 that it cannot apply any PE/KE below (and the upper block WTC2 disappears then too completely). The initiations are very suspect!
The PE/KE of any rubble produced after initiation below is just broken pieces and cannot be included in any gravity energy calculation as being applied to lower structure still intact to drive a gravity collapse - it just is broken structure of the lower structure. The only PE available is, as Bazant and Seffen points out correctly, the upper block ... but then they make the arroneous assumtion that it, the upper block, has uniform density and is applied to the structure below ... like a snow/soil avalanche. But it is not seen on any videos or photos.

You should evidently put your questions to the FBI.

 

[Architect]

Your bizarre theory is based, as ever, on your failure to grasp the basic structural design concept of the tower.

Let me repeat this, if only in order that later readers can be aware of how little knowledge you really have of the building. I'll write it in terms a second year structures student will understand, in order to give you a fighting chance.


Each of the WTC Towers was constructed in a similar tubular formation, reaching heights of 1,362 feet and 1,368 feet for WTC 1 and 2 respectively. The structures were designed as a combination of three main components: the external envelope or perimeter columns, the interior core columns, and the floors.

Each facade consisting of prefabricated steel lattices formed each building and collectively they were the world's highest load-bearing walls. The lattices were made up of more than 130 closely spaced vertical cantilevered steel columns, creating a "hollow tube" structure. Each column was itself a hollow 14-inch square steel box section placed at approximately 39 inch centres. These exterior columns served as wind bracers for the building to resist overturning forces such as high speed winds.

Each tower's core comprised a series of columns, beams, and bracing. The core was designed to support its own gravity load, the elevator system, and of course half of the floors. It did support the external structure. This design left the office space free of constricting interior columns.

Prefabricated steel trusses, 33 inches in depth, were welded to the exterior columns and supported the compiste steel and concrete floor plates of the two towers. These floors spanned the entire 60 feet to the core against wind loadings, deflection, and the like.

Not one person in the professional engineering community has produced any meaningful analysis which even suggests that the core, or the outer facade, can survive as anything other than an inter-linked structure. Not one. This is not surprising; the engineering and cost implications of such a design would be simply untennable.

The collapse sequence is well understood, based on visual evidence and structural modelling.

The fire results in failure of the floor trusses at a number of locations, which in turn pull the outer envelope inwards rather than shearing. Buckling impairs the structural perormance of the envelope, transferring the loads elsewhere, and rapid progressive collapse occurs.

As far as I can tell, Heiwa, your structural hypothesis is based upon a number of untennable assumptions which barely qualify as engineering including, inter alia:

- That steelwork is not susceptible to fire induced failure (although I note that you are gradually stepping back from this absurd claim).

- That the floors do not, in fact, pay a part in the overall composite structure and that the external envelope was designed to act as a freestanding structure in its own right.

- That columnar failure would only be precipitated by overloading immediately thereone, i.e. an end to end impact, and not by any interaction with the floor structure.

- That the fragmented nature of the collapse following initiation would have, as far as I can tell, have resulted in a more gradual increase in floor loadings which would, in turn, allow us to discount the overall kinetic energy arising from impact of the upper structure.

- That rendering mass as overall desnity rather than considering load paths, point loadings, and so on is an appropriate means of considering such kinetic energy issues as might arise.

I put it to you, as others have done before, that this is little more that a preposterous bluff which owes absolutely nothing to any branch of construction or structural engineering which those of us who are actually qualified in the field would understand.

It is particularly amusing that, in discussions pertaining to the hard realities around structural engineering and building design, you have adopted the position that your lay opinion is to be preferred no just to myself or NB but rather the entire engineering community - Arup, Nist, BRE, Bazant, Edinburgh University, Sheffield University, the authors of the Eurocodes, and indeed the rest of our field.

Under such circumstances, Heiwa, I really can only conclude that you must be ill. There is no way in which a purportedly competent and sane professional could so fail to grasp the basic analysis and then simply ignore cogent points put to him. I would therefore encourage you to cease your sensless posting and seek professional help, before it all goes too far.

 

[Heiwa]

1. Prefabricated steel trusses, 33 inches in depth, were welded to the exterior columns and supported the compiste steel and concrete floor plates of the two towers. These floors spanned the entire 60 feet to the core against wind loadings, deflection, and the like.

2. The collapse sequence is well understood, based on visual evidence and structural modelling.

3. The fire results in failure of the floor trusses at a number of locations, which in turn pull the outer envelope inwards rather than shearing. Buckling impairs the structural perormance of the envelope, transferring the loads elsewhere, and rapid progressive collapse occurs.

1. The floor trusses were generally bolted to the columns.

2. The collapse sequence is not understood at all. First PE>SE (local failures + freefall + impact + >90 impacts = none seen anywhere) and then in a FAQ Dec 2007 floors dropping down according Nist. Impacts can only occur between two solid objects, perfectly aligned. Basic. Do not exist in any steel structure.

3. A failed floor (local failure) cannot pull an outer envelope inwards. What would pull in the outer envelope? A floor broken in two?

Many people believe that when ships impact water/waves in rough weather, e.g. that the ship's bottom slams down onto the water surface or that the bow flare above water impacts an oncoming wave and that water/ship meets but it is all nonsense. The ship surface and the water surface are never perfectly aligned (flat to flat) for a solid impact to take place! You can test it yourself - drop a flat solid surface on an absolutely flat water surface and you will find that the air between the solid surface and the water will affect the water surface and make it rounded = no real impact. It is more obvious if you ripple the water a little. No impact at all! What is observed as an impact is only air trapped between the two surfaces that compresses ... and then explodes a a certain pressure (often about 10 bars) and most energy produces a big splash. For similar reasons an upper part structure of a WTC tower can never impact on the lower structure; no alignment, no solid to solid touch/impact, one part will be deflected by the other, neither part is solid, very small load bearing areas that can really impact each other, etc. Result? Most PE is lost into the air. That's why steel buildings never collapse on itself due to gravity. So the WTC collapse sequence assuming any sorts of impacts is just nonsense. Real impacts only occur between solid steel balls or similar to explain momentum transfers and no such things took place 911.

But please, copy/paste anything you find wrong in my article and explain what is wrong in lieu of vague references to unknown experts of all kinds about OT subjects.

 

[Architect]

It did not support the external structure. This design left the office space free of constricting interior columns.

An apparently minor but critical typo there.

 

[Architect]

1. The floor trusses were generally bolted to the columns.

Well there's a statement of the blindingly obvious.

2. The collapse sequence is not understood at all. First PE>SE (local failures + freefall + impact + >90 impacts = none seen anywhere) and then in a FAQ Dec 2007 floors dropping down according Nist. Impacts can only occur between two solid objects, perfectly aligned. Basic. Do not exist in any steel structure.

Wrong, wrong, wrong.

Firstly, no-one has uniform pancake collapse -which is what you're describing - as the udnerlying cause. Show me a linked reference, if you can. Secondly, you once again ignore the effects that destabilisation of the floor structure has on the outer and inner envelopes.

This is basic stuff. Why can't you grasp it?

3. A failed floor (local failure) cannot pull an outer envelope inwards. What would pull in the outer envelope? A floor broken in two?

Sag in the trusses. Really, have you even read the NIST report properly?

Many people believe that when ships impact water/waves in rough weather, e.g. that the ship's bottom slams down onto the water surface or that the bow flare above water impacts an oncoming wave and that water/ship meets but it is all nonsense. The ship surface and the water surface are never perfectly aligned (flat to flat) for a solid impact to take place! You can test it yourself - drop a flat solid surface on an absolutely flat water surface and you will find that the air between the solid surface and the water will affect the water surface and make it rounded = no real impact. It is more obvious if you ripple the water a little. No impact at all! What is observed as an impact is only air trapped between the two surfaces that compresses ... and then explodes a a certain pressure (often about 10 bars) and most energy produces a big splash.

Are you seriously trying to make a comparison between the interaction of a fluid and the collapse of two structural components? Is this what underpins your hypothesis?

For similar reasons an upper part structure of a WTC tower can never impact on the lower structure; no alignment, no solid to solid touch/impact, one part will be deflected by the other, neither part is solid, very small load bearing areas that can really impact each other, etc.

That is just so wrong that it hardly merits a reply. So 33000 tonnes were just going to gently slide off the bottom structure, were they?

Result? Most PE is lost into the air. That's why steel buildings never collapse on itself due to gravity. So the WTC collapse sequence assuming any sorts of impacts is just nonsense. Real impacts only occur between solid steel balls or similar to explain momentum transfers and no such things took place 911.

That's right, the 30,000 tonnes - in bits - would magically bounce sideways and would never cause an overload in the underlying structure! How could we all be so wrong?!?!

But please, copy/paste anything you find wrong in my article and explain what is wrong in lieu of vague references to unknown experts of all kinds about OT subjects.

It's been done already. You're just ignoring it, as ever. Just like you "forgot" that you claimed that steel was magically fireproof.


Get medical help.

 

[X]

Well, if gravity alone could not do the job, what happened? I only demonstrate in my article, in layman's terms, that WTC1,2 were not gravity driven collapses. Too little PE available and the PE/KE is not applied on the structure below, actually the PE/KE (the upper block) disappears before initiation at WTC1, and has tilted so far outside WTC2 that it cannot apply any PE/KE below (and the upper block WTC2 disappears then too completely). The initiations are very suspect!
The PE/KE of any rubble produced after initiation below is just broken pieces and cannot be included in any gravity energy calculation as being applied to lower structure still intact to drive a gravity collapse - it just is broken structure of the lower structure. The only PE available is, as Bazant and Seffen points out correctly, the upper block ... but then they make the arroneous assumtion that it, the upper block, has uniform density and is applied to the structure below ... like a snow/soil avalanche. But it is not seen on any videos or photos.

You should evidently put your questions to the FBI.

That is not an answer, and rests upon the assumption that "gravity alone could not do the job".
You have been repeatedly shown that this is untrue. But instead of realizing the outlandishness of your claims, instead of this question making you think that maybe your answer isn't correct, you launch into more absurd and incorrect theories.



Heiwa, Let me tell you something. I do not mean this as a personal attack, I am saying it as a last-ditch effort to get you to take a dispassionate look at exactly what it is you are claiming:

In Canada, you would be at serious risk of losing your engineering certification for your claims here and on your website. You make claims outside your area of expertise, but back them up by using your professional status as an engineer.
- You make claims that are wrong, and refuse to correct them.
- You maintain the position that every single expert in the relevant fields are wrong and amateurs, and that you, a ship deisgner, know more about buildings and structural mechanics than do people who actually design buioldings.
- You peddle your nonsense to children and other people without the technical knowledge to see the errors.
- You are falsely accusing the U.S. government of murdering it's own people.

It is dishonest. It is borederline incompetent. I do not doubt that you know a lot about nautical engineering. But you are out of your depth when it comes to buildings.
The professional responsibility you are shredding is the same professional responsibility that would have all knowledgeable engineers worldwide up in arms demanding answers (and listeneing to them) if there were indeed anything at all in their analysis or the evidence that did not fit with aircraft impact and fires. Engineers are professionals. They have to be, because their work is often critical to public safety.

Please stop.

 

[ElMondoHummus]

In Canada, you would be at serious risk of losing your engineering certification for your claims here and on your website.

Hmm... problem is, I don't think he has to worry about losing certification in Sweden:

Swedish engineers are not required to have a license or certification from a specific state or central organization.

Source: http://www.overseasdigest.com/country/Sweden.htm#Engineering

Assuming that Heiwa resides and practices in Sweden, that is.

 

[Architect]

Assuming that Heiwa resides and practices in Sweden, that is.

Oh for heaven's sake......they must be just about the only country in the EU that doesn't require registration/chartering of their engineers.

It explains a lot.

 

[Heiwa]

That is not an answer, and rests upon the assumption that "gravity alone could not do the job".
You have been repeatedly shown that this is untrue.

Where? PE>SE according Nist! Nonsense.

No, it is a well known FACT that if local failure occurs in an upper part of a steel structure, gravity alone will NOT destroy the whole structure due to that 'initiation'. The PE released due local failure is always diverted away by intact structure. Quite basic. WTC 1 and 2 are the only exceptions.

It seems we have different opinions.

But please feel free to copy/paste any errors you find in my article.

 

[Architect]

Heiwa

Don't make us laugh. We've responded umpteem times and challenged you to provide structural calculations. You've evaded such issues time and time again. You're not interested in debate, only your own personal delusion.

 

[Apollo20]

Heiwa's Point?

This debate is going nowhere, so let me offer this:

I believe Heiwa's main point is that the Twin Towers were like very tall cages. And the more a cage structure is multiply connected horizontally as well as vertically, the more robust it gets. So how can a cage, or a part of a cage, collapse/crush another cage?

Now that's a fair question. But I think the answer to this question is that such a collapse can in fact happen if the cage unit-cells are weakly inter-connected, and this was probably the case for the Twin Towers. WTC 1 & 2 had relatively weak welds and relatively weak bolts. The buildings could literally "fall to pieces" if struck/stressed in a particular way.

Thus there is no need for explosives to explain the collapse of WTC 1 & 2. The structure of each tower was very sensitive (anywhere below the 100th floor) to local lateral stresses/impacts + heating rates. As a consequence, certain conditions are capable of triggering a self-propagating domino-effect/unzipping type of collapse, especially in the case of top-heavy buildings such as the Twin Towers.

 

[Sizzler]

Look at the upper left side of the falling upper block. I never noticed the bowing of the perimeter columns so high up in the building. Did this occur before or after collapse initiation?

 

[R.Mackey]

Yes, NIST refers to this as "The Kink." It is strongly implied that this occurred after collapse initiation (but only just). Search for it in NCSTAR1-5A and NCSTAR1-6.