NIST's Evasion
NIST (National Institute for Standards and Technology)
was given a budget of tens of millions of dollars to
study the collapses of the World Trade Center skyscrapers.
Yet it avoided that charge in any meaningful sense.
Its final report admits that it didn't even attempt
to model the collapses.
The first critique to thoroughly expose NIST's evasion of
its task of investigating the collapses was provided by Sami Yli-Karjanmaa
on July 14, 2005.
The following excerpt includes more that half of the brief critique.
|
e x c e r p t
|
|
The first of the specific objectives of the NIST study was to
"[d]etermine why and how WTC 1 and WTC 2 collapsed
following the initial impacts of the aircraft
and why and how WTC 7 collapsed."
[3]
These questions are not answered for simple reasons:
Incredibly, the progressive collapse of the Twin Towers
has been left out of the computer models used:
"The global models of the towers extended from several stories
below the impact area to the top of the structure."
[4]
Thus the structurally intact floors 1-91 of WTC 1 and floors 1-77 of WTC 2
were excluded from the so called "global" models of the towers.
Correspondingly, the temporal dimension was cut short as well:
NIST gave itself the task of finding out
"[t]he probable sequence of events from the moment
of aircraft impact until the initiation of global building collapse."
[5]
...
In other words,
"Even without the modeling of the progressive collapse we had to postpone
the publication of the reports four times so we just didn't have time to do that.
And besides, the lower parts of the buildings simply did not slow down the collapse,
as everyone could see on TV, so why bother?"
In summary:
The reports by NIST say nothing about how -- and if! -- the collapse
was able to progress through dozens and dozens of structurally intact floors
without being stopped. If no external energy was available e.g.
in the form of explosives, this would have been the opportunity to show
that no such energy was needed. On the other hand, if some unaccounted-for
energy broke the supporting structures enabling the collapse to progress
with the speed it did, there would have been many good reasons not to try
to model the impossible, ie. a purely gravitation-driven collapse.
Stopping the analysis early enough also saves NIST from trying to explain
the symmetricality of the collapses (despite non-symmetrical impact damage and fires),
the almost complete pulverization of non-metallic materials as well as
the extremely hot spots in the rubble.
These remain as inexplicable by the official story as they have ever been.
One appendix of project 6 includes an interesting analysis of a dropping floor.
[8] According to the results, however, temperatures of
400 to 700 ºC are needed in order for the collapse to be initiated.
Unfortunately, the destruction of evidence at Ground Zero was so complete
that NIST can now only say that the steel components recovered demonstrate
that there was "limited exposure if any above 250 ºC."
[9]
NIST's collapse creed, repeated eleven times with identical wording
(and once with a slightly different one) in the report of project 6 dealing with
the collapse sequences, is this:
"
The change in potential energy due to downward movement of building mass above
the buckled columns exceeded the strain energy that could have been absorbed by
the structure. Global collapse then ensued."
[10]
In other words: "Once the top started coming down,
it was so heavy that the damaged columns could not stop it.
Neither could the undamaged columns of dozens of floors do that, it seems.
But we didn't need to model that for we've all seen that down it came."
Thorough, open, independent?
References:
[1] http://wtc.nist.gov/pubs/semerjian_remarks_62305.htm
[2] http://wtc.nist.gov/pubs/reports_june05.htm
[3] http://wtc.nist.gov/pubs/NCSTAR1ExecutiveSummary.pdf (75 kB), p.3
[4] http://wtc.nist.gov/pubs/NCSTAR1-6ExecutiveSummary.pdf (1.4 MB), p. lxii
[5] Ibid., p. lxiv
[6] http://wtc.nist.gov/pubs/NISTNCSTAR1-6DDraft.pdf (19.4 MB), p. 5
[7] Ibid., p. 169
[8] Ibid., p. 371
[9] http://wtc.nist.gov/pubs/NCSTAR1-3ExecutiveSummary.pdf (52 kB), p. xli
[10] http://wtc.nist.gov/pubs/NISTNCSTAR1-6Draft.pdf (17.5 MB)
|
Later, Jim Hoffman wrote a critique of NIST's report, which, although far more detailed
than Yli-Karjanmaa's, makes essentially the same central point.
|
e x c e r p t
|
|
To shield the reader from the evidence of controlled demolition,
NIST fills hundreds of pages with amazingly realistic plane crash simulations,
tedious details about fire tests and simulations,
and long lists of recommendations for improving building safety.
It calls its event narrative of each Tower,
which starts with the jet impact and ends at the point that
"collapse ensued,"
the "probable collapse sequence,"
but it is neither probable nor a collapse sequence.
NIST's misleadingly named "probable collapse sequence" is a mirage,
masking the explosive reality of the collapses
with a cinematic account of the crashes and fires.
NIST's theory stops at the moment that the
"upper building section began to move downwards,"
thus avoiding the longer timeline of the truss-failure theory
and any overlap with the time span
in which the demolition-like features appear.
Despite NIST's theory being even more incredible than its predecessors
(with spreading "column instability" triggering "global collapse"
in an instant) it works better as a mirage
because its timelines stop short of the collapses.
NIST's Report states that its first objective is to
"determine why and how WTC 1 and WTC 2 collapsed."
The Report does not fulfill that objective,
and hides that failure with misleading headings and disproportionate,
misapplied technical detail.
Its authors should admit that they have failed to explain
why and how the Towers collapsed,
and should call for an investigation that will address rather than avoid the issue.
|
Hoffman's critique points out that NIST's Report,
while avoiding even claiming to model the collapses,
implies but does not show that it modeled the onsets of the collapses.
The Report's section entitled
Results of Global Analysis"
describes the tops of the Towers first tilting
and then moving downward as intact blocks,
but there are no images in the Report of its computer models
showing this behavior.
The New Civil Engineer (NCE),
an engineering trade journal based in the United Kingdom,
published an article highlighting NIST's failure to publish
visualizations of its alleged analysis of "collapse initiation."
|
e x c e r p t
|
WTC Investigators Resist Call for Collapse Visualisation
WORLD TRADE Center disaster investigators are refusing to show computer
visualisations of the collapse of the Twin Towers despite calls from
leading structural and fire engineers, NCE has learned.
Visualisations of collapse mechanisms are routinely used to validate
the type of finite element analysis model used by the investigators.
The collapse mechanism and the role played by the hat truss at the top
of the tower has been the focus of debate since the US National Institute
of Standards & Technology (NIST) published its findings
(NCE 22 September 2005).
NIST showed detailed computer generated visualisations of both the plane
impacts and the development of fires within WTC1 and WTC2 at a recent
conference at its Gaithersburg HQ. But the actual collapse mechanisms
of the towers were not shown as visualisations.
University of Manchester (UK) professor of structural engineering
Colin Bailey said there was a lot to be gained from visualising the
structural response. "NIST should really show the visualisations,
otherwise the opportunity to correlate them back to the video evidence
and identify any errors in the modelling will be lost," he said.
University of Sheffield professor Roger Plank added that visualisations
of the collapses of the towers "would be a very powerful tool to promote
the design code changes recommended by NIST."
NIST told NCE this week that it did not believe there is much value
in visualising quasi-static processes such as thermal response and load
redistribution up to the point of global collapse initiation and has
chosen not to develop such visualisations.
But it said it would 'consider' developing visualisations of its global
structural collapse model, although its contract with the finite element
analysis subcontractor was now terminated.
A leading US structural engineer said NIST had obviously devoted enormous
resources to the development of the impact and fire models.
"By comparison the global structural model is not as sophisticated," he said.
"The software used has been pushed to new limits, and there have been a
lot of simplifications, extrapolations and judgement calls. This doesn't
mean NIST has got it wrong in principle, but it does mean it would be hard
to produce a definitive visualisation from the analysis so far."
|
NIST's WTC7 Report
Seven years after the attack,
NIST issued it's Final Report on WTC7.
In 2006 point man Shyam Sunder
had told a New York Magazine reporter in 2006 that
"We’ve had trouble getting a handle on building No. 7".
1
Now, in a press conference to wrap up their multi-year "investigation",
Sunder emphasized how "comformatable" they were with their new theory --
a theory that is breathtakingly innovative
in distancing itself from facts.
Cast aside are the diesel fuel,
which had been the key ingredient of collapse explanations since 2001,
and the severe structural damaged
that NIST's earlier reports made so much of.
All of that could be forgotten along with
the expeditiously destroyed steel
with NIST's new "elegant" theory, in which a single beam,
heated by fires, broke loose of its connections and took
the whole skyscraper down with it.
No need to investigate further, according to Sunder,
because their results are "incredibly conclusive".
And certainly no need to test for explosives because such testing,
according to multiple statements of NIST
"would not necessarily have been conclusive".
|
e x c e r p t
|
|
After years of talking about diesel fuel fires
and damage from the towers being
the causes of the near free-fall collapse of WTC 7, and then acting as if they
just couldn't get a handle on it, NIST now has a new "obvious" story.
The new story is based on a "new phenomenon" of thermal expansion whereby
fully insulated steel beams are exposed to temperatures of 600 ºC
in only 32 minutes. Believe it or not, NIST actually says this happened in
only a few seconds (NCSTAR 1-9, table 8-2, p 353).
This extreme temperature, which did not weaken the beams at all,
as would have
happened in WTC 1 or WTC 2,
broke all the shear studs, seat bolts and clip bolts
on all the beams of the east wall of WTC 7.
The beams then expanded linearly,
pushing the girder between column 79 and column 44 by a maximum of 2.2 inches,
causing that critical girder to buckle and fall away from columns 79 and 44.
We have seen that this "initial local failure" is not realistic.
This is because the fire times could not possibly have caused the high steel
temperatures cited, the steel would not have remained rigid
if those temperatures had been reached,
and the very slight thermal expansion would not have been
great enough to cause the extensive girder damage imagined by NIST.
From that tenuous position, we are led to believe
that the one fallen girder caused one column to buckle
and that meant the total destruction of this 47-story
building in a matter of seconds.
But who could have predicted all of this?
NIST admits that this is a rare phenomenon
that it had to work hard to prove.
"Failure of a floor beam in fire is a rare event, and, indeed,
there have been many building fires that have not resulted
in even local failures of the floor system.
The challenge was to determine if a fire-induced floor
system failure could occur in WTC 7 under an ordinary building contents fire."
NCSTAR 1-9, p 330
What geniuses knew that this new phenomenon
of the thermal expansion of several
floor beams in unison would cause this one hair-trigger girder to bring the
entire building down several hours before it actually occurred?
And if you believe all that...
NIST topped off this most ridiculous of explanations
with a truly bizarre consideration of a "hypothetical blast event."
First, NIST asks us to assume that it wasn't a planned demolition. We are
led to believe that no one would have placed explosive charges
around the entire building to cause what appears to everyone
who sees it as a completely symmetrical
and purely vertical near free-fall implosion.
On the contrary, NIST says that if WTC 7 was to have been a demolished, it
would have to begin with an assumption that most of their new story is correct.
That is, anybody wanting to bring the building down in a demolition event would
have obviously placed one gigantic bomb under that one all important column
-- column 79.
Therefore, let's play along with this dishonest pretense and see what NIST
says that would do.
A "Blast from the smallest charge capable of failing the critical
column would have resulted in a sound level of 130 dB to 140 dB at a distance
of at least half a mile. There were no witness reports of such a loud noise,
nor was such a noise heard on the audio tracks of video recordings of the WTC
7 collapse." NCSTAR 1-A, p xxxii
Essentially, NIST is saying that WTC 7 was not a demolition because
a big boom would make a big sound.
That, ladies and gentlemen, is the culmination of seven years of Bush Science.
|
References
1.
The Ground Zero Grassy Knoll,
|
page last modified: 2010-12-18
|
|
