If Belief in 9/11 Conspiracy were a US political party, it would rank #1

Originally posted by gottago

Originally posted by jthomas

You're not reading carefully. The investigation of course dealt with how and why the towers collapsed. And the conclusions demonstrated that the combination of plane crashes and unfought fires were sufficient to have weakened the damaged area enough to cause the upper sections of each tower to start falling. AND, once that started, the energy was enough to cause global collapse of the rest of the building

So, of course, once you know that, trying to model the collapse to the ground from the point the upper sections started to fall is irrelevant to ascertaining the initial cause. This is clear.

9/11 Truthers have to cling to a myth that one has to model the collapse all the way to the ground to ascertain the causes of the collapse when, clearly, such modeling is unneeded.

Oh, now I see the light! Let me try:

The buildings fell down but we don't need to know why, because they fell down.

If you would learn to read, you'd know that I said we know why WTC 1 and 2 collapsed.

Can you give me a good reason why you you have such trouble comprehending the written word???

Originally posted by bsbray11

Originally posted by jthomas
You're not reading carefully. The investigation of course dealt with how and why the towers collapsed.

How can you say that if they didn't even try to analyze the global collapses?

For the very reasons I have given you over and over and over. We already know the causes of the collapses. Learn to read better.

Originally posted by jthomas

Can you give me a good reason why you you have such trouble comprehending the written word???

Yes, because you are doing the writing.

If you would learn to read, you'd know that I said we know why WTC 1 and 2 collapsed.

I do know that you said "we" know why WTC 1 and 2 collapsed, but that's just you saying it.

You're purposely conflating onset of collapse with total collapse, so that total collapse becomes a foregone conclusion, and continue to ignore this ever since you've been caught out in it.

You've not provided the slightest proof of this remarkable claim.

At this point you're trolling, or you simply don't comprehend what's at issue.

Take your pick.

Originally posted by jthomas
We already know the causes of the collapses. Learn to read better.

You need to learn to read better.


I have asked at least twice now for you to post references for your information, and you still fail to do so.

NIST never demonstrated that global collapse was inevitable, or did any kind of analysis whatsoever.

Originally posted by gottago

You're purposely conflating onset of collapse with total collapse, so that total collapse becomes a foregone conclusion, and continue to ignore this ever since you've been caught out in it.

I clearly did not write "total collapse was a forgone conclusion," nor did I suggest it was a "foregone conclusion." So you assessment is incorrect. Go back and read again what I have written many times.




[edit on 17-3-2008 by jthomas]

Originally posted by jthomas

I clearly did not write "total collapse was a forgone conclusion," nor did I suggest it was a "foregone conclusion." So you assessment is incorrect. Go back and read again what I have written many times.

Semantic maneuverings again. Why are quoting what I wrote and flatly stating that I claim you've written it? Really, that's obvious deception. What a piece of work.

You've written nothing but unsupported assumptions on this subject. Still not a whit of proof...

Originally posted by gottago

Originally posted by jthomas

I clearly did not write "total collapse was a forgone conclusion," nor did I suggest it was a "foregone conclusion." So you assessment is incorrect. Go back and read again what I have written many times.

Semantic maneuverings again. Why are quoting what I wrote and flatly stating that I claim you've written it? Really, that's obvious deception. What a piece of work.

Because you I never suggested that it was a forgone conclusion.

Originally posted by bsbray11

I have asked at least twice now for you to post references for your information, and you still fail to do so.

There are many studies available to us all concerning the collapses of tall buildings. The real question is why you all have not done your own research in an effort to understand the issues involved.

There studies done before and after the NIST Report came out, all discussing - scientifically and structurally - what they know on the subject matter. I will list a few of them in my next post.

One thing you will take away from the studies is notso much how and why the collapses took place, but how to prevent such collapses.

I recommend that you read them. Some you will have to pay for.

Studies, Part 1:

Pre-NIST Reports
Progressive Collapse Basics.
www.aisc.org...
"Progressive collapse is the collapse of all or a large part of a structure precipitated by damage or failure of a relatively small part of it. The phenomenon is of particular concern since progressive collapse is often (though not always) disproportionate, i.e., the collapse is out of proportion to the event that triggers it. Thus, in structures susceptible to progressive collapse, small events can have catastrophic consequences."
[...]
"...the structure near the impact zone lost its ability to support the load above it as a result of some combination of impact damage and fire damage; the structure above collapsed, having lost its support; the weight and impact of the collapsing upper part of the ower caused a progression of failures extending downward all the way to the ground."

How did the WTC towers collapse: a new theory
www.sciencedirect.com... 1&_urlVersion=0&_userid=10&md5=021d81d7f11917e60d84959ab1e75c1c
"This paper uses a finite-element model to investigate the stability of the Twin-Towers of the World Trade Center, New York for a number of different fire scenarios. This investigation does not take into account the structural damage caused by the terrorist attack."
[...]
"The results are illuminating and show that the structural system adopted for the Twin-Towers may have been unusually vulnerable to a major fire."
[...]
"The collapse mechanism discovered is a simple stability failure directly related to the effect of heating (fire). Additionally, the mechanism is not dependent upon failure of structural connections."

Could the World Trade Center have been Modified to Prevent its Collapse?
scitation.aip.org...
"The feasibility of protecting tall buildings against progressive downwards collapse following catastrophic structural failure at high level is explored and various design suggestions made."

Progressive Collapse Basics.
www.aisc.org...
"Progressive collapse is the collapse of all or a large part of a structure precipitated by damage or failure of a relatively small part of it. The phenomenon is of particular concern since progressive collapse is often (though not always) disproportionate, i.e., the collapse is out of proportion to the event that triggers it. Thus, in structures susceptible to progressive collapse, small events can have catastrophic consequences."
[...]
"...the structure near the impact zone lost its ability to support the load above it as a result of some combination of impact damage and fire damage; the structure above collapsed, having lost its support; the weight and impact of the collapsing upper part of the ower caused a progression of failures extending downward all the way to the ground."


NIST Report
NIST NCSTAR 1-6: Structural Fire Response and Probable Collapse Sequence of the World Trade Center Towers
wtc.nist.gov...
"Global collapse occurred as potential energy of the falling upper structure exceeded the strain energy capacity in the deforming structural members."

Post-NIST Reports
Structural Response of Tall Buildings to Multiple Floor Fires
scitation.aip.org...
"The results of the analysis show that large displacements may occur in long span structural floor systems without failure, however, the interaction of the highly deflected floors with the exterior or perimeter columns can lead to structural collapse."

Collapse scenarios of WTC 1 & 2 with extension to generic tall buildings
www.era.lib.ed.ac.uk...

Determination of Fire Induced Collapse Mechanisms of Multi-Storey Steel Framed Structures
www.era.lib.ed.ac.uk...
"Following the events of September 11th 2001, understanding the performance of multi-storey buildings during large-scale fires has assumed greater importance. These events have highlighted the possibility of large uncontrolled fires lasting for several hours (WTC-7). Owners of high-rise buildings are seeking assurance that integrity can be maintained during similar elevated temperature situations. This work is part of a much larger study to evaluate the performance of high-rise steel-framed structures in the event of large uncontrolled fires, using primarily a computational approach. Given a building and its operating conditions, different fire scenarios are established. The choice of scenarios is established on the basis of probability of occurrence and also as a function of damage potential. Computational fluid dynamics models are used to predict critical conditions within pre-determined areas of the building. Emphasis is given to establish a proper thermal boundary condition for the structural elements. A three dimensional numerical model of the structure provides the basis for a structural finite element analysis to be carried out under combined static and thermal loading. Full investigation of the temperatures and stresses generated on structural members due to the design fire chosen are considered. Particular attention to detail is given to those members that are thought likely to contribute to total collapse through localised failure. This is done by combining CFD codes with finite element models. This paper will present a selection of results from the aforementioned investigation, with particular emphasis on the conditions that cause total collapse for the chosen case study."

Studies, Part 2


Progressive Collapse of the World Trade Center: Simple Analysis
cedb.asce.org...
"The collapse behavior of the World Trade Center towers is considered formally as a propagating instability phenomenon. The application of associated concepts enables the residual capacities of both towers after the onset of collapse to be formally estimated. This information is combined into a simplified variable-mass collapse model of the overall dynamical behavior. The resulting, nonlinear governing equation of motion can be solved in closed form, to yield compact information about the overall collapse conditions."

Structural Responses of World Trade Center under Aircraft Attacks
cedb.asce.org...
"At the September 11, 2001, terrorist attacks on the New York World Trade Center (WTC) Towers, extensive structural damage, including localized collapse, occurred at several floor levels directly impacted by the aircraft. Despite this massive localized damage, each structure remained standing for approximately 1 h or 1 h 30 min. Although the damage to the beams and columns in the perimeter tube of each tower were clarified in the published ASCE/FEMA report, the damage to the floor system and inner core columns were not estimated. The purpose of this study is to determine why the towers remained standing after impact through several analytical studies, including impact analyses using a simplified model to estimate the overall damage, a rigorous finite element model to estimate the local damage, and stress analyses after some structural members are lost. The results of the stress analyses show why both buildings did not collapse immediately after impact, and WTC2 collapsed sooner than WTC1."

A study on the collapse control design method for high-rise steel buildings
www.pwri.go.jp...
"...it is understood that in cases where vertical load supporting members are lost due to unexpected loads or to accident and where vertical load supporting members lose functionality due to large-scale fire, it is important to provide measures whereby local collapse does not lead to entire collapse. To achieve this goal, it is necessary to increase vertical load redistribution capacity by providing back-up systems for multiplying the number of loading routes, as shown in Table 1. Further, it is necessary to secure the plastic deformation capacity and fire resistance of individual steel members and joints between them."

jthomas,


Where is NIST's demonstration that global collapse was inevitable? I see above that they assert that the PE was enough, but where is the demonstration, the proof? Where do they figure it?

You said they didn't just say it, they demonstrated it. So put up or shut up.



Edit to ask: reading through all of the above excerpts and everything they reference and imply, do you really think you'd just catch it (especially not even looking!) if someone did something dishonest in there, unless you actually carefully looked at and thought about what they are saying? Like Valhall noticing that NIST was coming to conclusions a priori, or the testing just not being there, or the data being contradictory to the final hypothesis, or many details being intentionally left without being filled in. Have you ever noticed anything like that about the NIST report? If it exists, how do you think you would come to find out about it? Not with the stubborn and biased mindset you have now, just pouring through looking for the cliff notes to debunk us 9/11 nutballs, right? Do you even know what you're looking for?

[edit on 18-3-2008 by bsbray11]

Originally posted by bsbray11
jthomas,


Where is NIST's demonstration that global collapse was inevitable? I see above that they assert that the PE was enough, but where is the demonstration, the proof? Where do they figure it?

You said they didn't just say it, they demonstrated it. So put up or shut up.

Do you recall that I am responding to your request:

"I have asked at least twice now for you to post references for your information, and you still fail to do so."

I responded with TWO pages of references to help you understand the subject matter, including NIST.

You can start with NIST 1-6:

"NIST assembled a collection of nearly 150 hours of video footage and over 7,000 photographs, which were reviewed for insights into the structural performance of the towers. A timeline of significant events that characterized the weakening and eventual collapse of the WTC towers was developed with the photographs and videos that were time stamped. Quantitative information, such as the amount of inward bowing observed on the exterior walls of the buildings, was extracted from key photographs through image enhancement and scaled measurements. Key observations and the timelines were used to guide the global collapse analyses."

wtc.nist.gov...

Edit to ask: reading through all of the above excerpts and everything they reference and imply, do you really think you'd just catch it (especially not even looking!) if someone did something dishonest in there, unless you actually carefully looked at and thought about what they are saying?

In other words, you have reason to believe ALL independent, scientific studies done on building collapses before and after NIST completed its investigation should be treated as "suspect" because they are in line with the observed collapses of WTC 1 and 2? That ALL the data - math, physics, forensic analysis, and structural analysis - of the collapses doesn't count?

Like Valhall noticing that NIST was coming to conclusions a priori, or the testing just not being there, or the data being contradictory to the final hypothesis, or many details being intentionally left without being filled in. Have you ever noticed anything like that about the NIST report? If it exists, how do you think you would come to find out about it? Not with the stubborn and biased mindset you have now, just pouring through looking for the cliff notes to debunk us 9/11 nutballs, right? Do you even know what you're looking for?

[edit on 18-3-2008 by bsbray11]

So, in other words, the state of 9/11 Truth is that we must regard all scientific studies of global and progressive collapses as nothing more than "Cliff Notes." I can't even imagine anyone believing that.

That's very indicative of the way the 9/11 Truth Movement has operated all along. Data, evidence, research, and facts the Movement does not like is summarily dismissed as whooy.

reply to post by jthomas



So where is your response to what bsbray11 is asking for?

The question was

"Where is NIST's demonstration that global collapse was inevitable?"

So where is that *DEMONSTRATION*???

reply to post by talisman


Yeah, I'm still not seeing it, either.

Originally posted by jthomas
So, in other words, the state of 9/11 Truth is that we must regard all scientific studies of global and progressive collapses

Case histories of other high-rises globally collapsing: 0. Oklahoma City (the Murrah Building) was allegedly a partial "progressive collapse," the only 3 global ones all happened on 9/11.

I suppose the "science" you have in mind on this subject is "progressive collapse = always 'inevitable' once poised; no more thinking please!" It must be something along those lines, because you don't even seem capable of explaining how it was or even could be demonstrated to be "inevitable."

After you actually read the material I've presented, if it is still unclear, here's a question for you both:

How would you both go about investigating whether or not the circumstances of WTC 1 and 2 would lead to global collapse or not?

Then list how you think structural engineers, architects, physicists, chemists, and forensic scientists would do it. What is the methodology? Is your claim that NIST would have to model the actual collapse in order to understand IF global collapse would occur or not valid or not?

Please demonstrate and cite references.

Flashback:

Originally posted by jthomas

Originally posted by ANOK
To say global collapse was inevitable and doesn't need explaining is complete #e.

They didn't "say" it - they demonstrated it.

Are you finally conceding what a lot of the rest of us already know? You're not even trying to show us where NIST demonstrated the global collapse was "inevitable." You must also realize now, they just said it. Didn't demonstrate it.

Originally posted by jthomas
How would you both go about investigating whether or not the circumstances of WTC 1 and 2 would lead to global collapse or not?

Wrong question. The question should be, "What was the mechanism that propagated global collapses, ie 99% of the actual collapses?" If you want to ask what started it, we could even go back to the impacts and just assert that that was enough, the rest was inevitable. Why not? Or even building them. When you build Twin Towers, terrorists attack them, and they fall. It's inevitable! We don't need further study. No science involved. You just like to say that there was. In reality you wouldn't even know whether it was or not; you at least thought NIST actually supported everything they assert with evidence/references. Good morning, sleepy head! They don't.

[edit on 19-3-2008 by bsbray11]

Here's some more help for you brsbay11. Get back to me if you still don't understand what happened and why. I look forward to your refutation of global collapses of WTC 1 and 2 as the result of the crashes and unfought fires, and your evidence to the contrary.

Preventing Disproportionate Collapse
scitation.aip.org...
"'Disproportionate collapse' is structural collapse disproportionate to the cause; it is often, though not always, progressive, where "progressive collapse" is the collapse of all or a large part of a structure precipitated by damage or failure of a relatively small part of it. There have been many attempts to develop design guidelines and criteria that would reduce or eliminate the susceptibility of buildings to this form of failure. In recent years, the particular focus has been on the prevention of progressive collapse due to deliberate attack. The present study suggests, however, that these guidelines and criteria may be of limited value. Arguably the most important deficiency in the state of the art of design to prevent disproportionate or progressive collapse is uncertainty about the design event: We have the technology now to design for almost anything, but most recent building failures due to explosions and terrorist attacks have involved insults to the building not anticipated in design guidelines and criteria."


Progressive Collapse of Structures: Annotated Bibliography and Comparison of Codes and Standards
scitation.aip.org...
"Progressive collapse is one of the most under-researched areas in structural engineering due to the relative scarcity of the circumstances leading to progressive collapse. The current design standards and building codes provide limited prescriptive or performance-based guidance on analysis or design to guard against progressive collapse. The collapse of the World Trade Center on September 11, 2001, led to demands by the public to amend current building codes and provide protection against collapse caused by extreme events. Following September 11, the literature on progressive collapse mitigation has expanded significantly. Important issues examined by investigators include events leading to progressive collapse, assessment of loads, analysis methods, and design philosophy. This paper seeks to explore aspects of the current state of knowledge on progressive collapse in the technical literature. The paper also discusses loads, structural analysis requirements, and design approaches in United States standards and guides as well as selected international building codes and standards."


PROGRESSIVE COLLAPSE OF STRUCTURES
www.sh.tu-harburg.de...
"Progressive collapse is characterized by a distinct disproportion between the triggering spatially-limited failure and the resulting widespread collapse. If this disproportion is taken as the defining feature of progressive collapse, then the cause of initial failure, be it a local load or a local lack of resistance, is irrelevant to this definition."
[...]
"In terms of tragedy and losses the above mentioned cases of failure were far exceeded by the collapse on September 11th, 2001 of the twin towers of the World Trade Center. The impact of the airplane and the subsequent fire initiated local failures in the
area of impact. The ensuing loss in vertical bearing capacity was limited to a few stories but extended over the complete cross section of the respective tower [9, 10]. The upper part of the structure started to move downwards and accumulated kinetic energy. The subsequent collision with the lower part of the structure, which was still intact, caused enormous impact forces which were far beyond the reserve capacities of the structure. This, in turn, led to the complete loss of vertical bearing capacity in the area of the impact. Failure progressed in this manner and led to a total collapse."
[...]
"The first reason lies in the consideration of local instead of global failure. Correspondingly, design equations are usually defined and applied on a local level only (check of cross-sectional forces or element stability). Structural safety, therefore,
is likewise accounted for on the local level only. The global safety, i.e., the safety against the collapse of the entire system or a major part thereof, is a function of the safety of all the elements against local failure but also of the system response to local failure. The latter influence is neglected.
[...]
"The problem can be illustrated by expressing the probability, P(C), of a progressive collapse, C, due to an event, E:
P(C) = P(C LE)P(L E)P(E) (1) where P(E) = probability of occurrence of E, P(L|E) = probability of local failure, L, given the occurrence of E, and P(C|LE) = probability of collapse given the occurrence of L due to E [13]. The factor P(C|LE) is not reflected in current design codes. The probability of progressive collapse thus remains likewise disregarded."


Materials and structures (fascinating paper)
web.mit.edu...&%20Structures.pdf
"Ever since that day, structural engineers all over the world seek for explanations as to how and why the towers collapsed, and how to prevent such failures in the future."

reply to post by jthomas


I am seeing a lot of fluster, but no substance to what is being asked. Keep in mind you are always asking others to 'put up evidence'.

Again, the *DEMONSTRATION* please...

Originally posted by talisman
reply to post by jthomas

 

I am seeing a lot of fluster, but no substance to what is being asked. Keep in mind you are always asking others to 'put up evidence'.

I have. Please read it. Thanks.

And please demonstrate your claims for a change, talisman, since you have never done so. Not only do you have to refute NIST, you have to refute all the other papers I have posted.





[edit on 19-3-2008 by jthomas]

[edit on 19-3-2008 by jthomas]

Originally posted by jthomas

Originally posted by talisman
reply to post by jthomas

 

I am seeing a lot of fluster, but no substance to what is being asked. Keep in mind you are always asking others to 'put up evidence'.

I have. Please read it. Thanks.

And please demonstrate your claims for a change, talisman, since you have never done so. Not only do you have to refute NIST, you have to refute all the other papers I have posted.





[edit on 19-3-2008 by jthomas]

[edit on 19-3-2008 by jthomas]

Where does NIST *DEMONSTRATE* the Inevitability of GLOBAL COLLAPSE? All I am seeing is blunt assertion, no logical formula, nothing.