The MIT Paper and it's unfounded assumptions

[wrs]

Halo,
You have put so much gibberish on that other thread you started that I am going to follow your own technique, Im going to discuss the MIT paper on it's own thread. I want to point out first that this paper was written two days after the collapse in a vacuum of information.

The first thing it fails to do is justify the mass of the upper 20 floors which it claims is more than 20 times what the FEMA data says. The FEMA report tells us what the PE of the upper 20 floors is and from that we can calculate the mass. This paper was written two days after the collapse and made a number of invalid assumptions. I will quote the biggest one from the paper:

An important hypothesis implied in this analysis is that the impacting upper part, many floors in height, is so stiff that it does not bend or shear on the vertical planes and that the distribution of the column displacements across the tower is almost linear like for a rigid body.

It turns out that they cannot justify that from the video because we can clearly see the top of the building disintegrating as it falls (which is to be expected even accepting a pancake conjecture) and much of it's mass being spewed out the sides. This is true of both collapses but most notably the South Tower which was falling at about a 30% angle and managed to end up at the base in the footprint. It is clear from viewing the collapse of the South Tower that the upper stories disintegrate on the way down and thus do not hold together as a rigid body. It's easy to dismiss the rest of this paper based on the obvious failure of the original hypothesis.

In addition to this mistake, it also fails to recognize that if the upper floors are destroying the lower floors, one by one, the lower floors will no longer satisfy the rigid body requirement because of the damage they will have sustianed and hence cannot add to the mass and structure of the upper floors progressing to the next floor. Secondly we are to expect that the upper floors suffer no further damage as they fall but that isn't reasonable either. Whenever two bodies collide and there is plastic deformation, both are damaged. The floors are made of the same stuff and so the upper floors will have sustained a substantial amount of additional damage after crashing through just a couple or three floors below them.

Finally to get the ball rolling and justify the initial collapse, the paper assumes 800C heating of all of the columns in order to produce the buckling it requires to precipitate an initial collapse. According to NIST, the highest temperature that any of the beams reached was only 500C. This is from the studies done on the representative samples obtained by NIST.

This paper was a rush job before enough data was available and as such, it's easy to dismiss on the basis of the gross errors in it's assumptions. In fact it concludes the following:

Once accurate computer simulations are carried out, various details of the failure mechanism will doubtless be found to differ from the present simpifying hypothesis.

[Halophyte]

Halo,
You have put so much gibberish on that other thread you started that I am going to follow your own technique, Im going to discuss the MIT paper on it's own thread. I want to point out first that this paper was written two days after the collapse in a vacuum of information.


In the vacuum of CT conjecture too …


The first thing it fails to do is justify the mass of the upper 20 floors which it claims is more than 20 times what the FEMA data says. The FEMA report tells us what the PE of the upper 20 floors is and from that we can calculate the mass.


I never quoted FEMA's report in any of my threads. I use my eyes. Look at the South Tower as it begins to fall. See about twenty floors of mass ? I do.

All your attacks have been made on the assumption that I am defending FEMA report.

All of your critiques have been of their work … now that you’ve quit ignoring this study I first posted about two weeks ago - you got something else to deal with.


This paper was written two days after the collapse and made a number of invalid assumptions. I will quote the biggest one from the paper:

It turns out that they cannot justify that from the video because we can clearly see the top of the building disintegrating as it falls (which is to be expected even accepting a pancake conjecture) and much of it's mass being spewed out the sides.


The question you need to ask yourself is how much mass is lost (what you see) vs how much remains collapsing in the interior ?


This is true of both collapses but most notably the South Tower which was falling at about a 30% angle and managed to end up at the base in the footprint. It is clear from viewing the collapse of the South Tower that the upper stories disintegrate on the way down and thus do not hold together as a rigid body.


Brilliant deduction. The hypothesis implied requires the top structure to remain rigid to start the collapse and subsequent floors retain enough rigidity to progress the process. Elastic Dynamic Analyisis.

Don’t play stupid word games. You’re the math wiz, do the math.


It's easy to dismiss the rest of this paper based on the obvious failure of the original hypothesis.


You wish.


In addition to this mistake, it also fails to recognize that if the upper floors are destroying the lower floors, one by one, the lower floors will no longer satisfy the rigid body requirement because of the damage they will have sustianed and hence cannot add to the mass and structure of the upper floors progressing to the next floor.


As the collapse progress, the increase in velocity requires less mass to generate equal to, or more kinetic energy. The ratio of Resistance (Elastic or Inelastic) to Kinetic energy decreases because the area of impact remains the same, the load pressures per unit of area increases from floor to floor. This reduces the rigidity requirements from floor to floor. Until it’s all a pile of dust.


This you cannot logically dismiss. But you will …


Secondly we are to expect that the upper floors suffer no further damage as they fall but that isn't reasonable either. Whenever two bodies collide and there is plastic deformation, both are damaged. The floors are made of the same stuff and so the upper floors will have sustained a substantial amount of additional damage after crashing through just a couple or three floors below them.


The upper floors rigid mass is reduced as it falls, velocity increases requiring less rigid mass to impart the same or greater amount of energy to the next floor …. Re read what I just wrote, you’ll catch on.

But maybe not …


Finally to get the ball rolling and justify the initial collapse, the paper assumes 800C heating of all of the columns in order to produce the buckling it requires to precipitate an initial collapse. According to NIST, the highest temperature that any of the beams reached was only 500C. This is from the studies done on the representative samples obtained by NIST.


And it is YOUR assumption that heat losses were at 50% ?!?!?

What losses ?

Convection losses ?

Radiant losses ?

How much radiant energy was absorbed by what area ?

How much sprayed on fireproofing was destroyed by impact ?

What is the R value of the concrete floors above that contain and insulate the trusses within the fires ?

What was the total radiant core temp at center vertical supports and trusses ?

How much deformation of the truss system was required to start bowing of the floors ?

How many floors were affected ?

Interesting estimate of heat loss considering your loss of relevant information.


Boy, ain't that an educated guess ...


This paper was a rush job before enough data was available and as such, it's easy to dismiss on the basis of the gross errors in it's assumptions. In fact it concludes the following:


No chit mon, you think more data might help us create a more accurate computer generated study of a pancake collapse function or the shortcomings of building design ?

While you're playing cheerleader to the clueless, I noticed you had absolutely nothing to say about the calculations.

What’s wrong ?

Calculator battery dead ?


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[Large Sarge]

@WRS

I appreciate all you are doing, and with respect to Halo, he falls into one or more of the following categories below

1. Simple internet troll, I think if you search some of his history, you will find he likes to argue, as much as HT....

2. He is a religious zealot concerning the Bush doctrine, and anyone telling him something negative, is the equivalent of convincing a deeply religious person there is no God

3 Other deeper psychological issues not listed above?

Are there other motives/possibilities? yes, Will halo ever be right in his science or his theory on 9/11? No

Will he ever stop arguing? Seems doubtful
Does he enjoy it? He must

Some guys get their kicks out of porn, halo likes online verbal jousting....

For future reference on confused newbies, once we get tired of "Spreading the truth"

we can advise then to do a quick archive search... w/ Halo & anyone else....

Seems he is quite the little troll w/ all kinds of folks here

Thanks again WRS

[Halophyte]

Rah, rah, ree

Kick em in the knee

Rah, rah, rass

Kick em' in the ....


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[wrs]

The FEMA report is what Im quoting, it has real numbers, the MIT paper made up numbers and called them assumptions. As we can see, both NIST and FEMA contradict their numbers and those are the govt agencies with the best access to the wreckage.

Once the KE of the collapsing masses are used to deform the steel of the undamaged floor below them, it is lost and the mass of the upper floor slows down, that is simple physics and yet that didn't happen. Again, it is clear to see from the video that the upper floors disintegrated shortly into the collapse and hence they never were acting as a rigid body.

Conclusion, this paper is a whitewash that made fallacious assumptions which have since been shown wrong. Even the author of the paper admitted it would be shown wrong once a real analysis was done. This author didn't even know what size the columns were nor how many there were, he underestimated the size and strength of the columns and overestimated the mass of the upper floors in order to get the answer he wanted.

This paper proves nothing, it is based on false premises, you have nothing here and you have failed to answer any of my questions. If this paper analyzed the actual columns in the building and used the real mass of the upper 20 floors it wouldn't be able to make the conclusion it does. Ergo, you have done nothing but expose your ignorance by not understanding the paper and you have still failed to prove the pancake collapse conjecture.

[Halophyte]

Sorry, Halo you lose again.

It’s not about me. Your quotes,

“…if you want to understand this problem, you have to question the pancake conjecture, not the initial collapse conjecture. <snip> When the upper floors run into the stationary lower floor, they cannot continue at the same speed, they have to stop or slow down in order to accelerate the next floor downward.”

You have two important points you made here ;

1) “…question the pancake conjecture, not the initial collapse conjecture …”

Because you know there was enough energy and/or static weight applied to the surface area of the floor below to overload its live load limits. Good for you. I agree.

2) “… they have to stop or slow down in order to accelerate the next floor downward …”

Agreed energy conversion is the key, how much is absorbed by the undamaged floors in each succeeding floor collapse, but you miss one very important point that the study takes into account ;

Kinetic energy transferred back into the moving mass by deflection of structural members. That amount of energy deflected back into the moving mass only has to approach the energy needed to collapse each succeeding floor in order to approach fee fall velocity. It’s called Elastic Dynamic Analysis.

But you don’t want to talk about that. Instead you want to attach proven engineering platforms used in common structural engineering.

Conclusion, this paper is a whitewash that made fallacious assumptions which have since been shown wrong. Even the author of the paper admitted it would be shown wrong once a real analysis was done. This author didn't even know what size the columns were nor how many there were, he underestimated the size and strength of the columns and overestimated the mass of the upper floors in order to get the answer he wanted.

Conclusion, your calculations do not take into consideration the laws of conservation of energy by ignoring the structural dynamics of ductile metals a.k.a., Elastic Dynamic Analysis.

This paper proves nothing, it is based on false premises, you have nothing here and you have failed to answer any of my questions. If this paper analyzed the actual columns in the building and used the real mass of the upper 20 floors it wouldn't be able to make the conclusion it does. Ergo, you have done nothing but expose your ignorance by not understanding the paper and you have still failed to prove the pancake collapse conjecture.

Once again, your assumption that all structural members are inelastic is simply conjecture of ignorance on your part. Instead of looking at the structural dynamics, conservation and transfer of energy potentials by structural columns and beams, you play into the amature CT engineering game propagated by the CT artist and ignorance of the general public

Instead, you attack peer reviewed engineering study by qualified credentials that exposes your presentation as nothing more than armature speculation - a common theme among the CT websites.

You may now officially join the ranks of the quasi-professional CONspiracy theory cheerleaders.



Here's a kicker for you to burn-out some brain cells ;

From the beginning I've maintained that the open floor plan and longer than normal floor trusses aided to the collapse function of the towers. Check out the maximum deflection of beam spans as the length increases. Try calculating the energy potentials required, you find the energy potentials returned in a ringing wave to the moving mass.

Have fun. The collapse study isn't as simple as you try to maintain.

I'm not buying your bullshit, or your ad hoc attacks on the engineering profession.


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[Ponce Cuba]

My dos centavos......and I want you to think about this.

I believe that the Twin Towers were "air tight" in other words no open windows.....with me so far? .....good.

Now then, as the floors were collapsing from top to bottom and the air tight space of the floor below "should" have served as a "cushion" to slow down the incoming floor.....ok so far?

As the incoming floor breaks thru the cushion of air it should had pushed the air "out" (like a exploding balloon) and by doing this it should had "pushed" a lot of junk out into space (once again, like a balloon filled with powder).

The only "real" dust that I saw was the ones created at strategic places as the chargers were being detonated.

If it was the "fire" that made the buildings collapse you then should had been able to see the fire being blown out (like a blow torch).

Like I said before I don't have a PhD after my name so if there is one here then please tell me if I am right or wrong.......thanks.

[Halophyte]

This explains the huge dust cloud along the collapse front. The white dust below is the air column blowing out the windows below the collapse front of moving mass, other so called "squibs" are compression blow outs of vertical support columns, where fasteners fail and the columns are violently kicked out from their footings.

Notice all "squibs" happen AFTER the collapse begins.

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[Ponce Cuba]

sorry Halo but I don't buy that, that cloud dust was and ugly black from an explosion and and not clean powder from the bldg itself.

Also if that was the case it would had goneout in more than just the front entrance.

From floor 37 where the plane struck and down I say ok because you would have the air vents plus the weight of the above floors, but from 37 up? there were no holes and only the weight of the floors itself.

Both towers PLUS bldg 7 came down the same way and at the same speed.

[Halophyte]

I'm not selling anything. It's the CT sites that sell videos and books.

This is a 'not for profit' post.

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[wrs]

I am a Registered Professional Engineer in the state of Texas, you are not an Engineer at all and Im not making ad-hoc attacks. I made legitimate objections to this paper that you hold in high esteem. You still have never computed a single number that shows where there is enough energy available to continue a pancake collapse of the buildings. This analysis you reference doesn't either, it assumes smaller columns and more massive upper floors than reality so it's baseless at the outset. Yapping about elastic dynamics isn't meanignful, explain it and show some computations that demonstrate its relevance or drop it.

No kinetic energy is transferred back to the moving mass from the bending, buckling and breaking columns, the energy is used up warping the structure of the steel. You can't make a steel I-beam without expending a tremendous amount of energy to heat it and then shape it and you can't bend a cold column without a similar expenditure of energy. Once that energy has been spent, its gone. It's in the new shape of the steel molecules.

You are truly ignorant and willfully stupid..............

[Halophyte]

Let me guess. An I.E. ?

[hoarder]

Tell 'em Skyvike!
Discussions like this would really be great if the parties involved refrained from ad hominem and other logical fallacies. It would be unfortunate if the participants expended all that energy just to have a Jerry Springer Show conclusion.

Appeals to authority
Sarcasm
Strawman arguments

What is the benefit? None to the truthseeker.

It's unfortunate that public schools and universities have not weaned the public from these practices.

[Halophyte]

A critical structural issue contributing to collapse.

Structural elements contributing to Dynamics of floors collapse.

Another weak link in design.


Viscoelastic (VE) dampers are dependent on both relative velocity and displacement to dissipate energy. VE damping system in Twin Towers is a double-layer shear damper using a 3M material, which is a rubber derivative, glued to steel plate and angle irons. This material will carry some load (which is temperature-dependent and would be less than the two-bolt connection) as it displaces. As installed it has several functions:

1. It develops continuity moment at the end of joist girder, that is, the joist girders will behave as partial continuous members under Dead and Live load. It is partially restrained under Wind load.

2. It restrained the lower chord of the joist girder (in the direction perpendicular to the plane of the joist). Therefore it stabilizes the concrete diaphragm. Note that for a 4-inch thick concrete slab spanning 60 feet, it would buckle if there were no joist girder. It also transfers compression load through bottom chord.

3. Joist girder-column connection is a moment connection.

4. It reduces the energy to be absorbed by the joist girder and the columns under Wind load.

As the temperature rises, 3M materials would loose its load carrying capacity, i.e. its energy-dissipating capacity. This is equivalent as loosing the two-bolt connection because it will act as though there is gaps between the steel plate and the angle irons. As a result, several things would occur:

1. The joist girder is no longer a continuous member. Therefore, even under Dead and Live load, its top chord would rotate more relatively to its supporting column.

2. All the compression or tension force to the diaphragm would go through the top chords only.

3. More rotation between the top chord and its respective column under Wind load.

4. No more lateral restraint for the bottom chord and the joist girder could buckle laterally and the slab diaphragm would follow.
And the result is a tremendous demand on the connection between the top chord and its supporting column.

The VE damping system is a novelty design. First of its kind in the World. First of its kind implemented in a skyscraper. The reason I still think it is a design flaw is that:

In the 60’s and beginning 70’s there are many literatures about plastic design in steel including ASCE manual No 41. From J Heyman to Beedle, they all emphasize the importance of collapse mechanism in Limit Analysis. And in dealing with inelastic behavior such as VE damping system is engaging in Limit Analysis whether you want it or not because you have to think what will happen beyond the device limit.




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[DrillAndFill]

The MIT Paper and it's unfounded assumptions

This may be helpful to you.

The possessive pronouns in English mirror the regular pronouns.

So think "he, she, it" for the regular pronouns and "his, her, its" for the corresponding possessives. (I'm leaving out you/your and they/their for simplicity.)

My point is that the possessive of "it" requires no apostrophe in English.

"It's" is contraction of "it is."

Hence these examples:


The handsome face on the Krugerrand exerted its spell on her tender emotions.
"It's spelled with two r's," she protested, stroking the Krugerrand.My apologies if you meant to say "The MIT Paper and it is unfounded assumptions."

Now back to the topic at hand.

i AM, tHE duck!

QWAK

[wrs]

If you believe that calling Halo ignorant and willfully stupid is a personal attack then please remove the thread that is entitled

Paranoia and Childish Fear at GIM

That is not what the thread is about at all. It's a repost of a paper that was written 2 days after 9/11 and based on gross assumptions that later proved completely wrong. Halo is insulting the rest of the people that are attempting to question the govt wash jobs that hogged the entire media focus after this event occurred. Calling people that disagree with and show such papers to be totally wrong, paranoid and childish is a personal insult.

I have put my creds out on several threads but I will do it again here

B.A.C.S UT Austin, 1979
B.S.E.E UT Austin, 1981
MS Eng. Non-Linear System Theory UT Austin, 1990
P.E. State of Texas since 1988

I find Halos comments to be insulting and I find that he hasn't been able to compute anything that backs up his position so my conclusion is that he is ignorant which is correct because he demonstrates lack of knowledge. He seems to be willfully stupid in that he refuses to deal with any information that refutes the claims he holds forth and he constantly puts forth irrelevnat material as a way to sidetrack the discussion. By willfully stupid I mean that his stupidity is on purpose, it's not innate but it's done to keep other people from seeing that he has been shown wrong.

My intent wasn't to insult but to describe his actions to date on this section of GIM, which by the way is an excellent addition to the board.

[hoarder]

Skyvike,
I'm not surprised ours is not the only society in which ad hominem has not been diciplined. If we lived in a society where ad hominem was not tolerated, i.e. one in which people who used it would be strictly identified as users of such by media and academics, truth would prevail.
That said, it stands to reason that those who want to prevent the dissemination of truth would also want to legitimize ad hominem. Watch a few talk shows or listen to Flush Limbaugh and you'll see their purpose.

I'm not one to advocate censorship. I advocate admonishing anyone who uses poor logic by pointing out the use of logical fallacies, even when I agree with the person using them.
I've had people accuse me of ad hominem because I've pointed out logical fallacies. But there is an underlying distinction to be drawn, and thats if logical fallacies are used in place of reason in a debate.
If you start a thread titled "Hoarder is a Jerkoff" it's not a logical fallacy unless it is intended to disqualify a position I've taken on something.

If I point out the use of logical fallacies it isn't intended as inflammatory, just to keep the debate logical and on topic.
Though I generally agree with WRS's positions on this thread, it's evident to me his education (same for his opposition) has not diciplined him about logical fallacies. Truth exists independently of the messengers credentials (appeals to authority). Both sides have made credentials an issue, and this is not going to resolve the debate.
As you have stated, debate is a great learning tool. Those of us interested in seeking the truth need to be diciplined in logical fallacies to maintain it as such.

[Halophyte]

I repositioned figure 1 to orientate it to its true vertical mounting position.

See how the glued surfaces are all parallel to vertical loads ?

All loads on these plastic dampers are shear loads !

Each towewr was fitted with 10,000 Viscoelastic Dampers connecting all floor trusses to the outer vertical support columns. These damper connectors are almost impossible to fireproof due to their composite platic design, VE dampers do not use bolts or pins incorporated in its shear surfaces.

The maximum mid-span deflections of the long-span and short-span zones under the original WTC Design Criteria loads were approximately 1.55 in. and 0.70 in., respectively. That's all.

Failure of the VE damper shifts all vertical load limits to the top bolt/pins of the trusses. <edit> VE failure allows the trusses to hinge (rotate) on their top cord connertor bolt/pins. This allows the trusses to then have unlimited mid span deflection, well beyond design limits. What follows is floor sag and eventual buckling of floor trusses.


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[Halophyte]

I have put my creds out on several threads but I will do it again here

B.A.C.S UT Austin, 1979
B.S.E.E UT Austin, 1981
MS Eng. Non-Linear System Theory UT Austin, 1990
P.E. State of Texas since 1988

I find Halos comments to be insulting and I find that he hasn't been able to compute anything that backs up his position so my conclusion is that he is ignorant which is correct because he demonstrates lack of knowledge. He seems to be willfully stupid in that he refuses to deal with any information that refutes the claims he holds forth and he constantly puts forth irrelevnat material as a way to sidetrack the discussion. By willfully stupid I mean that his stupidity is on purpose, it's not innate but it's done to keep other people from seeing that he has been shown wrong.

My intent wasn't to insult but to describe his actions to date on this section of GIM, which by the way is an excellent addition to the board.


With all those hats you wear why don't you press on and do a complete Elastic Dynamic Anaylisis with VE dampers taken into consideration ?

You have the background, right ?

You have an old TI calculator, right ?

You want to prove your calculations as being accurate, right ?

If you refuse to do so it's not because you do not have the ability,

therefore,

it is willfull rejection of the need for proper anaylisis.


But you still refuse to thoroughly engage in your discipline.


Would that fullfill your definition of "willfull stupidity" ?


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[PatColo]

Halo must have so many

MILLIONS (http://reopen911.org/Contest.htm)


laying around already, he scoffs at the prospect of earning yet another

MILLION BUCKS. (http://reopen911.org/Contest.htm)


We should all thank Halo for spending his valuable engineering time laboring in vain to enlighten us here at GIM about the truthfullness of the gummit´s Official 911 CT, rather than grabbing his

MILLION BUCKS. (http://reopen911.org/Contest.htm)

[Large Sarge]

With all those hats you wear why don't you press on and do a complete Elastic Dynamic Anaylisis with VE dampers taken into consideration ?

You have the background, right ?

You have an old TI calculator, right ?

You want to prove your calculations as being accurate, right ?

If you refuse to do so it's not because you do not have the ability,

therefore,

it is willfull rejection of the need for proper anaylisis.


But you still refuse to thoroughly engage in your discipline.


Would that fullfill your definition of "willfull stupidity" ?


.

I think they tire of the game Halo....
JMO

the ventilator issue is a non-issue, because of the building was acting like a big chimney, then the smoke would not have been black....

simple observations tell you the fire was oxygen starved...

combine that with the molten steel observed for weeks afterwards...

I and so many others here could add to this list for a long time,

I do not think the truth matters to you, so go enjoy yourself in fantasyland, or trollville, whichever address fits your M.O.

[gpond]

http://911blimp.net/prf_FreeFallPhysics.shtml

Or this is even better:

http://goldismoney.info/forums/showpost.php?p=184050&postcount=3 written by our own Blue_pill_envy, who appears to be a natural teacher.