Commentary on the Bazant and Verdure article Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions; page 308; JOURNAL OF ENGINEERING MECHANICS (© ASCE); MARCH 2007:

by ShineOn*

At the outset it should be noted that if the articles published by Dr. Bazant are even modestly on target with regard to the analysis of the progressive collapse of the WTC Towers and (WTC 7), this still does not preclude the possibility that planted explosives were used to make sure that the demolition of the these buildings was achieved. This is basic logic and is contrary to one of his listed reasons for writing (and publishing) this latest article (2007):

“It could also help to clear up misunderstanding (and thus to dispel the myth of planted explosives).”

The formal fallacy of the above statement shows what appears to be a predisposition on the part of Dr. Bazant to only be willing to support one interpretation of these collapse events, namely that the airplanes and subsequent fires were the only causes of the rather “interesting” collapse sequences (dynamics) observed for the WTC Towers and WTC 7 on 9/11 (referred to throughout this commentary as the “official conspiracy story”).

These sorts of mistakes (of logic and/or fact) actually begin with the very first sentence of the recent article (2007). The first two parts of the first sentence of this paper states:

“The destruction of the World Trade Center (WTC) on September 11, 2001 was not only the largest mass murder in U.S. history, but also a big surprise for the structural engineering profession…”

The propaganda nature of the first part of this first sentence not withstanding, it really does not take a great deal of effort to refute such an absolute and poorly researched statement from Dr. Bazant. However, based on the definition of mass murder as “the act of murdering a large number of people, typically at the same time, or over a relatively short period of time,” perhaps it merely depends on what a person considers to be a relatively short period of time. This might suggest (at the very least) that Dr. Bazant does not consider the span of hours, days, months, years, decades, or even centuries to be a relatively short period of time.

And then a little further on in this recent article from Dr. Bazant there is the following passage that is worthy of some consideration:

“As generally accepted by the community of specialists in structural mechanics and structural engineering (though not by a few outsiders claiming a conspiracy with planted explosives), the failure scenario was as follows: …”

It is lamentable that a peer reviewed journal of this caliber has allowed for such a pitiful logical fallacy of “appealing to the majority” as a method of evincing an argument of what might have been the causes of the WTC building collapses (specifically the WTC Towers and WTC 7) on 9/11. What is said above by Dr. Bazant can be parsed as meaning that if you don’t “believe” the official conspiracy story, then you are an outsider and a conspiracy theorist; it is basically a rehash of the tired and over used mantra of “either you are with us or against us.” Of course, the official conspiracy story is also a conspiracy theory, so it appears that Dr. Bazant is willing to employ this rather over used “straw man” logical fallacy that has been the work horse of media manipulation for some decades already. It really is a sad day when a distinguished professor makes use of two rather ludicrous logical fallacies in a single sentence in the pursuit of scientific inquiry.

And besides which, the above passage from his article does not jive too well with the second part of the first sentence of the article. Am I supposed to believe that the initially surprised structural engineering community has come to their collective senses and now realize the correctness of the official conspiracy story in describing the destruction of the WTC Towers and WTC 7 on 9/11? Or is this just another instance of “catapulting the propaganda?” Of course, the detailed report on WTC 7 has yet to be completed.

Now, keep in mind that Dr. Bazant is partially trained as a theoretical physicist, specializing in classical mechanics, so it is expected that he will communicate his ideas with considerable accuracy and precision. Not only does he appear to fail at this task (e.g. does the “largest mass murder in U.S. history” include those perpetrated by the USA on other groups, both inside and outside the USA?), but he also makes claims with far too much certainty and far too little (if any) doubt; by now he should be expressing an abundance of doubt and skepticism towards the official conspiracy story in his recent article (2007) on this topic of the collapses of the WTC Towers and WTC 7, especially given the many well known observations that contradict his original analysis (2002). The history of science (and human affairs in general) is littered with such examples of people who have the appropriate training that choose to attack the messenger and ignore the observations, arguments, and reasoning that point to flaws in their hypothesis and/or the results derived from them. On this matter I am reminded of the thoughts of Hakuin that are also applicable to those of us that work in the physical sciences:

“For the study of Zen there are three essential requirements. The first is a great root of faith; the second is a great ball of doubt; the third is a great tenacity of purpose. A man who lacks any one of these is like a three-legged kettle with one broken leg.”

And we all know what happens to a kettle that has a broken leg…it will tip over on its side. And we might expect a similar behavior to occur for a tower that suffered asymmetric damage and began to collapse. In the case of collapsing buildings we certainly have no reason to believe a priori (as Dr. Bazant apparently wishes for us to do based on simple models) that the collapses of the WTC Towers and WTC 7 should progress with a high degree of symmetry all the way to their foundations without some additional help in the form of controlled demolition devices. I am quite troubled by the lack of integrity on the part of people and agencies in not considering the possibility of the controlled demolition hypothesis. It appears these people and agencies see it as their mission to only consider supporting the official conspiracy story; at a minimum this is bad science and at a maximum it will perhaps turn out to be complicity after the fact.

If a theoretical physicist chooses to set up a physics problem with the intent of achieving a desired conclusion (while ignoring relevant facts and/or observations to the contrary), it may in some cases (such as in the simple models developed by Dr. Bazant) be possible to do so. But this does not necessarily indicate that the assumptions and/or approximations that went into setting up a given model are correct or that the conclusions derived from them can or do correctly account for the observed reality, even if at first glance they appear to do so.

And this latter issue of matching theory with observations (experiments) is the bedrock upon which the “scientific method” is built. I’d at least expect an honest and ethical scientist to acknowledge this point and state the obvious limitations of their initial assumptions and approximations at some point in a given article on a given topic, especially one as complex as collapsing steel framed high-rise towers, and also to suggest real world experiments that could help to prove or disprove a given model.

Instead of performing to this sort of expected level of academic and intellectual integrity, Dr. Bazant chooses in the recent article (2007) to steadfastly rely on the conclusions of his own previous simplified model (2002), which for many (or most) of us paying a modest amount of attention now know, based on a total review of all the relevant evidence, both physical and otherwise, is to an unreasonably high degree of probability likely to be incorrect:

“In broad terms, this scenario was proposed by Bažant (2001), and Bažant and Zhou (2002a,b) on the basis of simplified analysis relying solely on energy considerations. Up to the moment of collapse trigger, the foregoing scenario was identified by meticulous, exhaustive, and very realistic computer simulations of unprecedented detail, conducted by S. Shyam Sunder’s team at NIST. The subsequent progressive collapse was not simulated at NIST because its inevitability, once triggered by impact after column buckling, had already been proven by Bažant and Zhou’s (2002a) comparison of kinetic energy to energy absorption capability.”

The above passage makes it clear that not only has Dr. Bazant in this recent article (2007) declared that there is no need for large computer simulations of the collapse dynamics, he is also contradicting what he had previously claimed in the first article (2002), namely that such large computer simulations would be appropriate:

“The details of the failure process after the decisive initial trigger that sets the upper part in motion are of course very complicated and their clarification would require large computer simulations. For example, the upper part of one tower is tilting as it begins to fall ~Appendix II!; the distribution of impact forces among the underlying columns of the framed tube and the core, and between the columns and the floor-supporting trusses, is highly nonuniform; etc. However, a computer is not necessary to conclude that the collapse of the majority of columns of one floor must have caused the whole tower to collapse.”

And even in the above passage Dr. Bazant is thrashing about trying to convince us that large computer simulations of the dynamics of the collapse of the WTC buildings are not necessary, claiming instead that the simplified analysis he has presented is enough to “prove” what would happen.

Now, these statements above in the first article (2002) from Dr. Bazant should get the attention of nearly all physical scientists as being quite suspicious and capricious, since we all know that simplified models generally depart from more comprehensive and detailed models on a range that goes from small differences that are relatively inconsequential out to large differences that are quite instructive in showing the limitations and inaccuracies in derived results that often arise from making too many simplifying assumptions and/or using unrealistic approximations. There are also a great many instances when simple models do not even allow for certain observed behavior in real world physical systems, and it is only when some small perturbation is accounted for that the models actually begin to predict what is observed in experiments. And for a complex and large extended structure like the WTC buildings, claiming that the derived results of simple models as “proof” of what would happen seems at best to be disingenuous when coming from a person with the training and achievement that Dr. Bazant has acquired.

In the addendum to the first article (2002), Dr. Bazant suggests that large computer simulations might reveal differences of a factor of 2, but again he does not show enough doubt (or perhaps humility) in recognizing that the differences seen in large computer simulations of the collapse dynamics could amount to a couple of orders of magnitude. At least as disturbing (and perhaps more so from my perspective) is his lack of interest in the symmetry of the dynamics of collapse, as this would be a major blow to the simplified models presented by Dr. Bazant if large computer simulations could not reproduce the observed nearly complete and relatively symmetric collapse sequences of the WTC Towers. (Of course, the problem with such a possible mismatch could be with the large computer simulations, but this could quite appropriately be investigated more thoroughly through controlled experiments.)

It is also quite reasonable for us to expect an honest and ethical discussion (or analysis) by Dr. Bazant to have at least questioned or complained about the lack of completeness and transparency in presentation (that might properly be considered a foundation principal of the “scientific method”) on the part of NIST in not releasing all of the details of their computer simulations, even though these (supposedly) only deal with the lead-up to the collapse (initiation) trigger. Instead, Dr. Bazant appears to embrace the computer simulations performed by NIST while basically ignoring the necessity of conducting exhaustive real world experiments to help confirm this type of theoretical modeling, which, of course, is a major breach of the proper application of the “scientific method.”

Dr. Bazant has set up the “analysis” of the problem of these collapsing buildings by dividing them into two distinct parts, the collapse trigger (for the initiation of a collapse) and the subsequent progressive collapse. Furthermore, the problem has been tacitly set up in the first paper (2002) with the assumption of a symmetric trigger (initiation event):

“For our purpose, we may assume that all the impact forces go into the columns and are distributed among them equally. Unlikely though such a distribution may be, it is nevertheless the most optimistic hypothesis to make because the resistance of the building to the impact is, for such a distribution, the highest. If the building is found to fail under a uniform distribution of the impact forces, it would fail under any other distribution.”

But what might the more probable asymmetric failure mode look like in the real world? Dr. Bazant does not ventures into a discussion (or analysis) of what we might expect to observe if the collapse trigger is asymmetric or if the collapse trigger is asymmetric and these two (supposedly distinct) events – collapse trigger and progressive collapse – are not well isolated in time, but instead were considerably overlapped in time. While it is quite reasonable to state that a given force concentrated in a smaller area will cause more damage at the impact location(s) than if that same force were spread out uniformly over a larger area, it is an unsubstantiated leap of logic to imply that the outcome for these different scenarios would necessarily result in nearly identical dynamics. Furthermore, as Dr. Bazant even stated, the former case of an asymmetric collapse trigger is much more likely (based on a qualitative argument of the behavior of distribution functions). What then would an asymmetric collapse trigger and perhaps a mixing in time of these two events – collapse trigger and progressive collapse – mean with regard to the observed dynamics of a progressive collapse? Is this somehow related to the refusal of NIST to make available to us “outsiders” all of their computer simulation data? Many of us apparently have an intuitive sense that the observed nearly complete and relatively symmetric collapse sequence of any one building on 9/11, let alone three buildings, is about as probable as seeing a tossed coin land on its edge and stay in this relatively unstable configuration. A more rigorous analysis invoking stability theory would seek to address the role that perturbations would play in the expected dynamics of the events observed on 9/11. I certainly find it difficult to believe a priori that enough of the building support structure would fail nearly simultaneously (or in a short enough period of time) based only on asymmetric airplane impact damage and what were most likely to be asymmetric fires to produce the observed nearly complete and relatively symmetric collapse sequences of the WTC Towers. And even if a collapse trigger were symmetric (which, as noted above, is highly unlikely), this is still not a sufficient “proof” that the subsequent dynamics of a collapse would proceed with such a high degree of symmetry and nearly to completion; a basic understanding of perturbation theory would lead a competently trained physical scientist to have serious doubts and reservations about such a claim.

It should also be pointed out (and I’ll leave it to other people or perhaps myself to follow up on this issue at another time) that the calculations made by Dr. Bazant in the first article (2002) do not appear to account for the core columns as contributing to the ability of the WTC Towers to withstand lateral forces during the observed tipping phase of the upper portion of the South Tower, and that he appears to discount entirely the core columns in the initial collapse phase when stating without a satisfactory amount of details:

“…the upper part may be assumed to move through distance h almost in a free fall...”

Indeed, is it a reasonable (and not clearly stated by Dr. Bazant) assumption that enough columns, perimeter and/or core, failed almost simultaneously so that an “almost” free fall motion of the upper part of the South Tower onto the lower part? This sort of assumption does not appear to be plausible based on the NIST computer simulations suggesting that 50 to 75 percent of the 47 core columns suffered no damage by the airplane impacts, and those that did suffer damage were graded from completely severed to light damage in four steps. And it is difficult to believe (a priori) that enough of the undamaged core columns plus those that were not severed would fail catastrophically all at the same time (or even nearly simultaneously) so as to not provide considerable resistance to an “almost” free fall drop of the upper portion onto the lower portion of either WTC Tower. And if the failures of the core columns were not nearly simultaneous and/or complete, what might the observed collapse sequence (dynamics) have been? Would a collapse sequence, if it were to happen at all, proceed with such a high degree of symmetry and nearly to completion?

And what exactly does it mean to “move almost in free fall?” There are perhaps too many such examples of vague qualifiers used in this first article (2002) by Dr. Bazant that require careful consideration: how much deviation from free fall of the upper portion of a WTC Tower onto the lower portion is required such that his simple analysis in the first article (2002) will not result in a progressive collapse based on the stated and implied assumptions and approximations?

Moving almost in free fall also brings up the issue of how fast the WTC Towers and WTC 7 collapsed with a high degree of symmetry nearly all the way to their foundations: is it reasonable to expect that such massive structures would collapse so quickly – basically in a free fall time interval – without the help of planted explosives? (Obviously, I’m quite doubtful that the answer to such a question would be in the affirmative.) This point of concern has been raised by many people and so there is little need for me to dwell on it here, except to point out that Dr. Bazant does not appear to be the least bit interested in this rather relevant observation and makes no attempt (meaningful or otherwise) to explain it in his simple models.

(A couple of other perhaps less relevant questions about the first article by Dr. Bazant (2002) might be: how did he decide on the choice of stiffness factor, C, used in his simplified modeling of the spring-like nature of the lower portion of the Towers, and why were such values not made available to him from an archived source of detailed information on these buildings? In fact it appears that throughout his analysis he had to use or calculate approximate values of the material properties, values that it seems reasonable to expect should be available from original blue prints and tests run during the design and construction of the WTC buildings.)

Furthermore, in the case of the WTC Towers and WTC 7 no attempt has been made by Dr. Bazant to reconcile the observed persistent hot spots in the debris field that were recorded in satellite spectra for several weeks after 9/11. It was later revealed during the removal of the debris field that the recorded hot spots were most likely the result of molten steel. How and why would there be molten steel in such a debris field several weeks after 9/11? Even if WTC 7 collapsed due to fires on the lower floors (as Dr Bazant has proposed in the addendum to the first article (2002)) that resulted from the prolonged burning of a liquid fuel (perhaps diesel fuel) on the day of 9/11, and perhaps had little to do with the damage suffered higher up in this building from falling debris from the WTC Towers, there are, of course, still symmetry considerations to take into account. Would these fires on the lower floors (or in the sub-structure) have been sufficiently hot and spread out to cause the observed nearly complete and relatively symmetric collapse of WTC 7? Furthermore, if such fires were raging on the lower floors, it seems reasonable to expect that the fire fighters would have noticed and made comments on them? And finally, it seems quite unlikely that such liquid fueled fires would result in what appears to be molten steel in the debris field for several weeks after 9/11. Of course, these questions of persistent hot spots and molten steel can be investigated further, both through real world experiments and computer simulations.

(We have read reports that the steel from the collapsed WTC buildings was shipped off, melted down, and turned into steel that was then used in the construction of a battle ship, and who knows what else. I can’t help but wonder if any of that steel was set aside and preserved in its original 9/11 collapse condition. I wonder what socio-political consequences might result if thorough tests were run on that steel confirming the use of demolition devices on 9/11?)

What about the explosions in the substructure of the WTC Towers many seconds before the impact of the airplanes? Dr. Bazant does not acknowledge these observations, both by eyewitnesses, and even more compellingly for a physical scientist, in the comparison of seismic records to the FAA flight data records. (What about the black boxes from the airplanes that would have contained an abundance of meaningful flight data?)

If building design and safety is of such paramount importance, as Dr. Bazant makes reference to in his articles, then why was the physical evidence contained in the debris field, evidence that might have helped to more accurately determine the nature and causes of the collapses, removed and destroyed with considerable efficiency and under relatively high security? Not once does Dr. Bazant appear to question or complain about this very obvious mistake of destroying valuable physical evidence. (And it does seem to be a curious situation that large computer simulations of the collapse dynamics have not been undertaken by other qualified people and discussed with a wider audience, at least with regard to building design and safety.)

In spite of the efforts of Dr. Bazant (and others such as NIST), it is abundantly clear to a good many qualified people that the official conspiracy story is highly unlikely and so the remaining evidence, physical and otherwise (including every last scrap of data at NIST), should be turned over to independent and honest groups of people for further investigations. Two questions then come to mind: Can such teams of investigators be formed and can the USA be compelled to turn over all of the remaining evidence?

(This article has been entirely written on my own without as yet any peer review, so any mistakes or omissions are entirely of my own doing, and I apologize in advance for any such blunders that may later be revealed.)

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* ShineOn wishes to remain anonymous... for now. If you have a message for ShineOn, post it in the comments thread, and I'll make sure it is passed on. -r.