Here's what I posted the last time Rosie's nonsense was posted here:
She starts out by claiming that "ALL" the steel was removed and shipped off to "Canada" ... er ... "China", "right away". She says there is no metal to test. That is absolutely false. Hundreds of structural engineers and other investigators had plenty of time to visit the WTC site and see the steel insitu, before the steel was removed. Then it went to Fresh Kill where again they got to examine it and retain those samples they considered important to understanding what happened. And tens of thousands of pieces of steel are still being retained for historical purposes and future studies. Rosie is either uninformed or a partisan liar.
Next, in the video, she says that WTC 7 "got hit by nothing". She's either uninformed or a liar. It got hit by significant amounts of debris from the collapse of the towers. That debris ripped a huge hole out of the south side of building. According to the firemen who where on the scene, a 20 story high hole.
Then she claims there were "pools of molten steel" under all three buildings. Well I challenge you to name a single eyewitness who has actually and verifiably used the word "pool" to describe what they saw. I challenge you to name a single expert in fire or steel who says finding molten steel was impossible given the circumstances. I challenge you to tell us what kept any steel that was molten, molten for over 6 weeks after the collapse. Rosie seems to think it was bombs. Show me how that might work.
Next, she claims it took the towers "9 seconds" to fall and that is the same as "free-fall". Well her claim is FALSE. From numerous credible sources (including actual videos of the collapse which one can time) one can learn that the towers actually took about 15 seconds to collapse. One can look at hundreds of still images of the collapses and immediately see that there was debris free-falling much faster than the collapsing level of the towers were descending. She surely has to have seen these images. So Rosie is either a liar or hasn't bothered to apply the least bit of thought to interpreting what she saw or the least bit of energy into investigating the issue.
So not only do professionals in the areas of structures, demolition, materials, fire or macro-world physics NOT agree with Rosie. The facts of the matter don't either. All she is really doing is hurting the effort to find out what really happened on 9/11. There are good questions to ask but if *truthers* make no effort to stop idiots like Rosie from muddying the water with nonsense and lies, you will never find the truth. People like her are the *truth* movement's worst enemy.
And in anticipation of nolu_chan's "notice", let me add:
: Truth Movement members almost seem unable to post articles that aren't deceptive or contain outright lies about what happened to the WTC structures and the Pentagon. And they seem to have particular trouble dealing with visual materials that prove their claims false. Why is that?
They continue to claim the towers collapsed in 10 seconds when video clearly shows they took 15 seconds to collapse. They continue to claim the entrance hole in the Pentagon was less than 20 feet across when photos convincingly prove it was closer to 90 feet. They continue to make an assortment of similar, demonstrably false claims despite all efforts to get them to change their ways.
Why can't *truthers* face the truth? They (and we) will never find out what really happened on 9/11, if they can't do that. Because a *Truth Movement* cannot be founded on disinformation and outright lies. That should be obvious to all. But apparently they can't see that either. It is sad.
#21. To: BeAChooser, Nolu Chan, Christine, Zipporah, Kamala, Red Jones, SKYDRIFTER, Everyone Interested In How Silly The Government's Official Collapse Story REALLY Sounds (#1)
So not only do professionals in the areas of structures, demolition, materials, fire or macro-world physics NOT agree with Rosie. The facts of the matter don't either.
I wonder if someone had asked EVERY structural engineer and demolition expert in the world prior to 9/11 if it would work to bring down a structure like one of the twin towers by flying a large jet into the top third of it, how many would have said "Hey - that MIGHT work!"?????
Answer: PROBABLY NOT A SINGLE ONE WOULD HAVE.....
BUT, demolition experts the world over should be VERY thankful to OBL, and those 19 Mooslim cohorts that set out to prove the worlds "experts" wrong!!! They showed that not only DOES it work, but with an extremely high success rate! In fact, 100% success rate (it would have worked on the Pentagon too, but that one was a little to "sprawled out")!
Just think of all the profit potential this has for demolition firms... Hell, all they need is to purchase some decommissioned aircraft; have it outfitted with remote control capability (Systems Planning Corporation - [Zakheim's old haunt] can help them with that, it's their specialty); buy 10,000 gallons of jet fuel (around 30 grand at today's prices); and in less than 2 hours have that sucker down!!!!! It'll save god-only-knows how many man-hours rigging buildings for weeks and months in advance, plus the costs of the explosives themselves, and the need for high paid professionals to handle those explosives. And that's for one of the world's LARGEST structures!! Why shit, if it's a small enough eye-sore (like a 20 story run-down old office they need to "take out" to make room for a parking lot for the new bank) they could probably even get by with a little old twin-engine Cessna - and get the job done REALLY dirt cheap!!!
Wonder when Controled Demolition Inc is gonna start using this newfound technology???
Just think of all the profit potential this has for demolition firms...
Especially when they can demonstrate that this new procedure also can take any nearby bonus building insured for $800M, drop it into its own basement, eliminate incriminating documents held by the Government that could cost billions, and leave all the surrounding buildings standing.
Especially when they can demonstrate that this new procedure also can take any nearby bonus building insured for $800M, drop it into its own basement, eliminate incriminating documents held by the Government that could cost billions, and leave all the surrounding buildings standing.
Just goes to show - when you want technology done RIGHT, go ask the big thinker that motivates around on horseback and lives in caves...
#32. To: innieway, nolu_chan, christine, Ricky J., Zipporah (#25)
Here are a few of recent quotes from Dr Greening:
Even NIST argues that no structural element in the Twin Towers saw a heat flux much higher than about 100 kW/m^2 for more than about 15 minutes.
As for NIST being CONSERVATIVE in its estimates of heating by the fires, if you read how case A and B were arrived at you will find that NIST made assumptions or changes to the FDS to achieve higher temperatures in going from case A to case B! For example, soffits were (arbitrarily) added to deliberately create a high temperature environment close to the ceilings in case B!
What was the justification for doing that? --------------------------------------------------------------------------------
Oh yes, and about those NIST fire simulations.
See NIST NCSTAR 1-5G and the discussion of the experimental and computer model UNCERTAINTY.
Uncertainty in the SFRM thickness was such that the uncertainty in the steel temperature was 20 % from this alone.
Now add the uncertainty from the thermo-physical properties of the materials in a truss assembly from things like the moisture content of the Blaze-shield...
Then add the uncertainty in the steel temperature due to the uncertainty in the heat release rate of 20 %...
Then look at Tables 12-9 and 12-10 and see variations of as much as 400 deg C in the predicted temperatures of a particular WTC 1 floor at a particular time.
Then see NIST NCSTAR 1-5F for an explanation of the difference between case A and case B and tell me if this is good science, or just self-fullfilling. --------------------------------------------------------------------------------
The dislodging of fireproofing is not proven. It is an hypothesis that allows NIST to calculate that the steel weakened sufficiently for the towers to collapse. But there is no PROOF this happened.... hence it is nothing more than a self-fulfilling prophesy.
In this respect the NIST study is not a scientific investigation of the collapse of WTC 1 & 2. It's a feel-good study about whether or not the Twin Towers met the applicable codes. Unfortunately for NIST the towers were built during code changes that resulted in a moving target for the designers (and NIST!). Some things that were ok at the start of construction were eventually not ok. --------------------------------------------------------------------------------
NIST has assumed conventional "fuels" were the only source of heat and are therefore stuck in the hydrocarbon flame temperature box. This limits the achievable air temperatures to about 1100 deg C (I think!). NIST realize this and even invoke the presence of "soffits" to trap more heat near the ceilings in case B -see NCSTAR 1-5F. --------------------------------------------------------------------------------
In NIST NCSTAR 1-2 we find figures showing the estimated damage to the floor trusses and floor slabs. For WTC 1 these show severe damage only to floors 95 and 96, with minor damage to floors 94 and 97. Nevertheless in NCSTAR 1-6 NIST show insulation damage to FIVE floors! More precisely, the diagrams, such as those in Figure 5-14, indicate that about 30 % of the insulation was "damaged" on floors 94, 95, 96 and 97, plus minor insulation damage to floor 98. How could floor 94 be as damaged as floor 95 when the damage estimate is based, as NIST clearly state, on this criterion?
"If the room furnishings were damaged or destroyed by the debris field, then the insulation on the steel trusses ABOVE these furnishings was assumed to be dislodged."
But this is not the only problem with NIST's analysis of insulation damage in the Twin Towers because NIST is very vague about the meaning of the term "insulation damage". I would assume that "damage" means partial destruction or removal. However, it appears that "damage" actually means "complete removal" when applied to the FDS model.
In this sense the NIST Report is not "CONSERVATIVE" as it claims to be. In fact, I would say that NIST removed insulation until heating of the steel sufficient to bring down the towers was achieved. This is why I claim that the NIST Report is a self-fulfilling prophesy. --------------------------------------------------------------------------------
My concerns are centered on the performance of passive fire protection materials on the truss assemblies in the collapse of WTC 1 & 2 and statements made by engineers in the NIST report on this VERY IMPORTANT topic.
So let's look closely at the NIST Report's statements on "damage" to the passive fire protection, or SFRM on the trusses in the Twin Towers, as in these quotes:
NCSTAR 1-2: "The aircraft impact damage to the EXTERIOR of the WTC towers could be visibly identified from the video and photographic records. However, no visible information could be obtained for the extent of damage to the INTERIOR of the towers."
And:
"The extent of dislodged fireproofing was ESTIMATED by considering fireproofing damage only to structural components in the direct path of the debris."
And:
"The truss floor system on floors 94 through 96 were damaged and sagged downward as a result of the impact loading."
So far so good...., but now we go to NCSTAR 1-6 to find more information on the question as to HOW NIST actually estimated the thermal insulation damage:
"The insulation damage estimates were conservative as they ignored possible damaged and dislodged insulation in a much larger region that was not in the direct path of the debris but was subject to strong vibrations during and after the aircraft impact. A robust criteria to generate a coherent pattern of vibration-induced disloging could not be established."
And:
"Where partition walls and furnishings remained intact, the insulation was also ASSUMED to remain intact."
And:
"This ASSUMPTION was consistent with the level of modeling detail... if substantial portions of the insulation were removed."
At this point I start to get the feeling that NIST is admitting that it really is unable to say anything definitive about the true extent of "insulation damage".
But "insulation damage" is key to NIST's explanation of the collapse of WTC 1 & 2.
And the NIST Report is supposed to convey the message "CASE CLOSED"
Nevertheless, NIST's conclusions appear to be based on "estimates", "indications", "if" and "might have resulted in" statements and an almost total lack of meaningful experimental data! --------------------------------------------------------------------------------
The place to look for NIST's estimates of the loss of SFRM is NIST NCSTAR 1-5G. Here you will find diagrams indicating estimates of the "fireproofing damage" for WTC 1 & 2. Focussing on WTC 1 for simplicity, I would say that NIST's diagrams suggest that fireproofing was removed from over 25 % of the floor areas for floors 95, 96, 97 and 98. That would imply that about 25 tonnes of insulation was dislodged by the aircraft impacts!
NIST also estimate that, on average, accelerations of over 40 g's, and sometimes as high as 300 g's, were required to dislodge SFRM from planar steel surfaces by hard impact.
So much for the idea that the SFRM was easy to dislodge. --------------------------------------------------------------------------------
As for NIST being CONSERVATIVE in its estimates of heating by the fires, if you read how case A and B were arrived at you will find that NIST made assumptions or changes to the FDS to achieve higher temperatures in going from case A to case B! For example, soffits were (arbitrarily) added to deliberately create a high temperature environment close to the ceilings in case B! What was the justification for doing that?" --------------------------------------------------------------------------------
NIST's diagrams suggest that fireproofing was removed from over 25 % of the floor areas for floors 95, 96, 97 and 98. That would imply that about 25 tonnes of insulation was dislodged by the aircraft impacts." --------------------------------------------------------------------------------
See NIST NCSTAR 1-5G and the discussion of the experimental and computer model UNCERTAINTY.
Uncertainty in the SFRM thickness was such that the uncertainty in the steel temperature was 20 % from this alone.
Now add the uncertainty from the thermo-physical properties of the materials in a truss assembly from things like the moisture content of the Blaze-shield...
Then add the uncertainty in the steel temperature due to the uncertainty in the heat release rate of 20 %...
Then look at Tables 12-9 and 12-10 and see variations of as much as 400 deg C in the predicted temperatures of a particular WTC 1 floor at a particular time. --------------------------------------------------------------------------------
NIST is not consistent in its reporting of the tilting of WTC 2 prior to collapse. Thus in Figure 9-14 (page 308) of Chapter 9 we read in reference to WTC 2 just before global collapse:
“The entire section of the building above the impact zone…began tilting as a rigid block about 7° - 8° to the east and about 3° - 4° to the south. …. The building section above impact continued to rotate to the east as it began to fall downward, and rotated to at least 20 to 25 degrees.”
However, on page 169 of the NIST Report, in a Section called Observations and Timeline of Structural Events, we read in reference to WTC 2, (See item 11 of Table 6-2):
“ The building section above the impact area tilted to the east and south. …. Rotation of approximately 4 to 5 degrees to the south and 20 to 25 degrees to the east occurred before the building section begins to fall vertically.”
Thus we see NIST claiming, on the one hand, that WTC 2 “rotated 20 to 25 degrees as it began to fall”, while on the other hand claiming elsewhere that WTC 2 “rotated 20 to 25 degrees before it began to fall.”
The suggestion that WTC 2 rotated by up to 25 degrees before it began to fall is very significant since it would indicate that the top of WTC 2 fell over rather than fell down! --------------------------------------------------------------------------------
In truth, the NIST Report is seriously flawed in many respects. It is inconsistent and contradictory in the way it treats the tipping of the upper section of each tower. It assumes that global collapse ensues without modeling the collapse. Its fire simulations generate such a wide array of temperature profiles as to be essentially useless. Its assumptions about the loss of thermal insulation are mere speculation. It ignores the important effects of massive releases of corrosive gases in the fires. Its metallurgical analysis of the steel is perfunctory. It ignores evidence (micron sized spheres) for the presence of molten iron in the towers prior to collapse. It mentions sulfidation, which it does not explain, while ignoring chlorination. And finally, NIST still cannot explain the collapse of WTC 7 after 6 years of trying. --------------------------------------------------------------------------------
However, if any WTC collapse theory is to gain full acceptance it must, at the very minimum, be able to explain certain well-documented phenomena such as:
· Sudden on-set of the collapse of each tower
· Near free fall descent of the block of floors above each impact zone
· Pulverization and ejection of concrete during the collapse
· The completeness of the destruction of each tower
· Sustained high temperatures in the rubble pile long after 9/11
Most, if not all, of these phenomena have been quoted as being problematic in some way to the currently proposed collapse theories. --------------------------------------------------------------------------------
To who like the NIST Report - great! Then perhaps you could explain how NIST's collapse initiation mechanism works with maximum pre-collapse downward displacements of only 33 cm? --------------------------------------------------------------------------------
I think the collapse of the Twin Towers was extremely complex. That's why NIST took so long to come up with its collapse model. Trouble is the model itself gets so complex you start to lose any sense of cause and effect. It's a bit like these climate change models..... you can get a believable answer that may be completely wrong. So, I guess I am complaining about NIST's approach and failure to consider the collapse itself. I know that wasn't part of its mandate. --------------------------------------------------------------------------------
Now the NISTIANs are convinced that theirs is the one and only TRUE STORY because they have studied what happened with their engineer's tool box. --------------------------------------------------------------------------------
NIST, in its fire simulations, tried very hard to get steel (>95 % iron) to temperatures above 1000 deg C but failed! This is not surprising because NIST was using kerosene or hydrocarbon/cellulosic-based fuels. NIST WANTED high temperatures to support the idea that the structural steel was weakened by heating effects.
Nevertheless, some steel appears to have melted in the WTC prior to the collapse of the buildings. Interestingly some of the NISTIANs posting on this site appear to be bothered by that, preferring to deny the physical evidence for molten iron. --------------------------------------------------------------------------------
Conspiracy theories only come from doubt. --------------------------------------------------------------------------------
I am curious what Bush meant when he said we should not "tolerate outrageous conspiracy theories". --------------------------------------------------------------------------------
It would probably be the bureaucrats at NISTthat would be the problem. The "we must have consensus" guys. --------------------------------------------------------------------------------
However, I would say that the presence of molten iron in the WTC is inconsistent with the NIST Report’s conclusion that temperatures in the towers during 9/11 were well below the melting point of iron or steel."
Please explain why you now have no trouble with molten iron in the WTC because some "experts" say molten iron is to be "expected" in building fires; meanwhile NIST cannot generate temperatures within 400 deg C of the melting point of iron!
Which "experts" do you prefer to believe? --------------------------------------------------------------------------------
it is sadly lacking in some contentious areas. Thus, when it comes to the pulverization of the concrete, the ejection of debris, the chemical analysis of WTC dust, etc, the NIST Report is of little or no use.
Of course, there are those who would say that post-collapse initiation issues were of no interest to NIST but I would argue that this is simply not true! A good example would be the metallurgical examination of recovered steel samples. NIST concludes that the samples were in the debris pile at the WTC site when the corrosion products developed. Thus NIST asserts WITHOUT PROOF that the observed degradation of the WTC steel occurred AFTER THE COLLAPSE OF THE BUILDING. Interestingly, the FEMA Report is more equivocal on this topic. Thus in Appendix C of the FEMA Report we read in reference to the infamous sulfidation of the steel: “It is possible that the corrosion is the result of long-term heating in the ground following the collapse of the buildings. It is also possible that the phenomenon started prior to collapse and accelerated the weakening of the steel structure.”
I find it quite amazing that such an important issue remains unresolved to this day. But I guess it’s no more amazing than the fact that the cause of the collapse of WTC 7 also remains unresolved! --------------------------------------------------------------------------------
NCSTAR 1-5G, page 91: "It should be noted that there is a wide variation of time-temperature curves that hold at different points in the structure and that these curves DO NOT resemble those from a standard time-temperature curve used in furnace tests."
So it is good to see NIST spelling out this kind of discrepancy! --------------------------------------------------------------------------------
In this PREFACE we find GOALS and OBJECTIVES listed separately. Interestingly the GOALS appear to be engineering goals and the OBJECTIVES are more obviously scientific. So I guess NIST achieved it's engineering goals... but, ironically, failed on some scientific objectives?!?! --------------------------------------------------------------------------------
See NIST NCSTAR 1-5G and the
discussion of the experimental and computer model UNCERTAINTY.
Yes, modeling is an uncertain business. But what Mark
doesn't tell you is that fire code models are still widely regarded as the
best means currently available of determining conditions inside complex
burning structures. And note that despite all these uncertainities, the peak
temperatures that steel samples were determined to have experienced agreed
quite nicely with what the models computed steel would have seen in the
locations from which those samples came.
The dislodging of
fireproofing is not proven. It is an hypothesis that allows NIST to calculate
that the steel weakened sufficiently for the towers to collapse. But there is
no PROOF this happened....
Actually, there is quite a
bit of evidence this happened. First, as pointed out in the NIST reports,
visual imagery shows that fireproofing did come off structural elements in the
towers. Second, engineers didn't suggest this happened without good reason.
Those reasons are clearly identified in the NIST reports. To suggest that
fireproofing wouldn't come off during a high speed impact is actually the more
ridiculous notion. Which is why no real experts in steel and fireproofing or
impact have joined Dr Greening or the *truth* movement in suggesting that.
Now readers should know that Mark in a previous discussion of this subject
declared that NIST concluded "vibration played no role in shaking off the 2.2-
2.5 inches of upgraded SFRM". Well that was false. What NIST did was say that
loss of fireproofing due to vibration was not included in the models. They
said "insulation damage estimates were limited to areas subject to direct
debris impact."
"The insulation
damage estimates were conservative as they ignored possibly damaged and
dislodged insulation in a much larger region that was not in the direct path
of the debris but was subject to strong vibrations during and after the
aircraft impact. A robust criteria to generate a coherent pattern of vibration-
induced dislodging could not be established due to (1) the numerical noise
inherent in the acceleration time-histories on structural components obtained
from the aircraft impact analyses, and (2) lack of data on the strength of
insulation materials under such a high rate of loading with sharp peaks in a
very short duration. However, there were indications that insulation damage
occurred over a larger region than that estimated. Photographic evidence
showed insulation dislodged from exterior columns not directly impacted by
debris (NIST NCSTAR 1-3C). The towers underwent a period of strong impact
loading for about .6 to .7 s. Further, video analysis showed that WTC 2
vibrated for over 4 minutes after aircraft impact with amplitudes in excess of
20 inches at the roof top (NIST NCSTAR 1-5A). First person interviews of
building occupants indicated that building vibrations due to aircraft impact
were strong enough to dislodge ceiling tiles and collapse walls throughout the
height of both WTC towers and to cause nearly all elevators to stop
functioning (NIST NCSTAR 1-7)."
Now as to whether fireproofing would have
been dislodged by direct impacts of plane debris, here are some excerpts from
http://wtc.nist.gov/NCSTAR 1-2.pdf (the final NIST report on this
subject):
***********
5.2.3 Damage to Fire Protection for Structural
Steel
The aircraft impact simulation models included not only the
structural components of the towers and aircraft, but also representations of
the partition walls and building contents and furnishings (modular office
workstations). The results of the analyses included damage to the partition
walls, workstations, and structural elememts. Such damage estimates were
crucial for the estimation of areas with dislodged insulation as explained in
this section.
Estimates of the post-impact condition of the fire
protection was based on criteria that considered damage to structural
components, building partitions, and furnishings along with the debris field
as calculated from the aircraft impact analyses. Estimates for the extent of
dislodged insulation considered insulation damage to structural components
only in the direct path of debris, as follows:
- Core columns had sprayed
fire-resistance material (SFRM), gypsum wallboard enclosures, or a combination
of both. Insulation was assumed to be dislodged from the columns if they were
subject to direct debris impact that could fail wall partitions in the
immediate vicinity. The representative bending strength of building partitions
in the impact simulations was 500 psi (NIST NCSTAR 1-2), while the
representative adhesion and cohesive strength of SFRM measured in the
laboratory by NIST was generally less than 12 psi (NIST NCSTAR 1-6A). Gypsum
column enclosures were also assumed to have a lesser representative strength
than wall columns.
To consider that insulation on core columns was
damaged, the predicted debris impact had to be sufficient to fail building
partitions immediately in front of the columns. If the wall partitions
remained intact in the core area after interactions with the debris field,
then the insulation on core columns behind these partitions was assumed to
remain intact. If wall partitions were damaged or destroyed by the debris
field, then insulation on core columns behind these partitions was assumed to
be dislodged over that floor height.
- To consider that insulation on
exterior columns was damaged, the debris impact had to damage or destroy
office furnishings (modular office workstations) adjacent to the columns. If
the office furnishings remained intact after interaction with the debris
field, then the insulation on the inside face of the exterior columns behind
these furnishings was assumed to remain intact. If the room furnishings were
damaged or destroyed after interaction with the debris field, then the
insulation on the inside face of the exterior columns in the vicinity was
assumed to be dislodged over that floor height. The other three faces of the
exterior columns were protected by windows and/or aluminum cladding and were
assumed to have no insulation damage.
- To consider that SFRM on floor
trusses was damaged, the debris impact had to be sufficient to damage or
destroy room furnishings (modular office furniture) in the same area of the
affected floor. If the room furnishings remained intact, then the
insulation on the steel trusses above the furnishings was assumed to remain
intact. If the room furnishings were damaged or destroyed by the debris field,
then the insulation on the steel trusses above these furnishings was assumed
to be dislodged.
The insulation damage estimates were conservative
as they ignored damage and dislodged insulation in a much larger region that
was not in the direct path of the debris but was subject to strong vibrations
during and after the aircraft impact (BAC - the rest of this paragraph
was quoted earlier but basically it indicates that photographic evidence shows
that vibrations were sufficient to dislodge insulation from structural
elements not impacted by debris.)
****************
Now apparently,
it's Dr Greening's (and Mark's) opinion that debris which could destroy
partitions and structural members in the analysis models could not remove
sprayed on fireproofing with measured adhesive and cohesive strength of less
than 12 psi? Frankly, I think this is yet another case of someone with no
expertise in a given subject making claims he knows nothing about. Dr Greening
should stick to chemistry ... such as the composition of thermite and the
conditions underwhich thermite like reactions would occur. He only embarrasses
himself, like that sub-atomic physicist named Jones embarrassed himself, when
he makes declarations in areas for which he has little education and NO
experience.
Now that isn't the first instance in which Mark has been
dishonest in his description of NIST and the facts. Here's a direct quote by
Mark in a previous discussion of the fireproofing and the temperatures reached
in the fire:
"Even without SFRM, the time the office fires burned in
the area of limited outer girder bowing, wasn't long enough to raise steel
temperatures. The limited heating and suspected loss of SFRM to the perimeter
columns played no role in the collapse. All steel tested from the fire zones
bare this out.
Contrary to what Marked claimed, the steel tests
actually validate the NIST modeling because the tested specimens did not come
for the regions in the simulations where they found the highest temperatures.
They came from regions in the models where similar temperatures to those
determined for those test specimens were calculated. Second, the steel test
procedures used were limited to specimens subject to relatively low
temperatures (roughly 250 C) because they depended on paint still being on the
specimens. Third, the detailed analyses done by NIST and reported in NCSTAR 1-
6 clearly show that the temperatures in structural members without
fireproofing were indeed high enough for long enough to seriously weaken
structural members.
Mark went on to claim
"No matter what airliner
impact case NIST plugged into the model A,B,C or D, no simulation produced the
observable events of impact and the debris path."
"The exterior wall damage was the one structural system for which direct
visual evidence of the impact damage was available. Therefore, the comparison
of the calculated and observed exterior wall damage provided a partial
validation of the analysis methodologies used in the global impact analyses.
A comparison of the north exterior wall observed and calculated damage from
the base case WTC 1 global impact analysis is shown in Figure E-28. The
comparison of the calculated and observed damage indicated that the geometry
and location of the impact damage zone were in good agreement. This agreement
in the position and shape of the impact damage served to validate the geometry
of the aircraft model, including the aircraft orientation, trajectory, and
flight distortions of the wings."
"The comparison also indicated a
good agreement in the magnitude and mode of impact damage on the exterior
wall. The exterior wall completely failed in the regions of the fuselage,
engine, and fuel-filled wing section impacts. Damage to the exterior wall was
observed all the way out to the wing tips, but the exterior columns were not
completely failed in the outer wing and vertical stabilizer impact regions.
Failure of the exterior columns occurred both at the bolted connections
between the column ends and at various locations in the column depending on
local severity of the impact load and the proximity of the bolted connection
to the impact. The agreement of both the mode and magnitude of the impact
damage served to partially validate the constitutive and damage modeling of
the aircraft and exterior wall of the tower."
Here is what the report
says about base case WTC 2 analysis:
"The comparison of the calculated
and observed damage indicated that the geometry and location of the impact
damage were in good agreement. This agreement served to validate the geometry
of the aircraft model, including the aircraft orientation, trajectory, and
flight distortions of the wings. The agreement of both the mode and magnitude
of impact damage served to partially validate the constitutive and damage
modeling of the aircraft and exterior wall of the tower."
And for the
more severe case analysis:
"The calculated damage to the south wall
from the more severe WTC 2 global impact analysis is shown in Figure E-54. A
comparison of the south exterior wall observed (Figure E-46a) and calculated
(Figure E-54) damage from the more severe WTC 2 global impact analysis
indicated that the calculated and observed magnitude and mode of impact damage
were still in good agreement."
And then there is this from the same
report
*****************
"The observables available to help validate
the global impact analyses included the following:
- Damage to the
building exterior (exterior walls and floors in the immediate vicinity of the
impact) documented by photographic evidence.
- Aircraft debris external to
the towers (landing gear for WTC 1 and a landing gear and an engine for WTC 2)
as documented by photographic evidence.
- Eyewitness accounts from
survivors who were inside the towers (blocked or passable stairwells).
An
example of such comparison was a detailed comparison between the observed and
calculated damage (from the base case analysis) to the north wall of WTC 1 and
the south wall of WTC 2. The comparison included the mode, magnitude, and
location of failure around the hole creatd by the aircraft impact. The color
code included in the following: (1) green circles indicating a proper match of
the failure mode and magnitude between the observed and calculated damage, (2)
yellow circles indicating a proper match in the failure mode, but not the
magnitude, (3) red circles indicating that the failure mode and magnitude
predicted by the calculation did not match that was observed, and (4) black
circles indicating that the observed damage was obscured by smoke, fire or
other factors. The comparisons shown in Figure E-62 and Figure E-63 for WTC 1
and WTC 2, respectively, indicate the overall agreement with the observed
damage was very good."
Not all the observables were perfectly matched by
the simulations due to the uncertainties in exact impact conditions, the
imperfect knowledge of the interior tower contents, the chaotic behavior of
the aircraft breakup and subsequent debris motion, and the limitations of the
models. In general, however, the results of the simulations matched these
observables reasonably well."
********************
Mark is trying
to paint a false picture of the NIST analyses. Just as he is trying to paint a
false picture about the validity of statements by Dr Greening on subjects Dr
Greening knows little about ... either through education or experience.
And here's another example of Dr Greening doing that. He states
NIST also estimate that, on average, accelerations of over 40
g's, and sometimes as high as 300 g's, were required to dislodge SFRM from
planar steel surfaces by hard impact. So much for the idea that the SFRM was
easy to dislodge.
First of all, keep in mind that NIST
did not assume that any SFRM was dislodged due to motions of the structure.
Only due to impact. And second, how high of accelerations does Dr Greening
think occur during a hard impact? Do the numbers that he quoted have anything
to do with such estimates? NO.
It states that "for values
representative of the upgraded thermal insulation on the floor trusses, an
acceleration of about 80 g would be required to dislodge a 2.5 in. thick layer
of well-bonded SFRM from a planar surface." For bars, the report states "the
smallest required acceleration is about 40 g, which corresponds to a large bar
having a thick layer of the higher density SFRM with low strength ...
snip .... For a 1.2 in. diameter bar with 2.5 in. thickness of SFRM and
density of 19 pcf, which are representative of the conditions of the upgraded
insulation on the floor trusses, the acceleration required to dislodge the
SFRM would vary from 55 g to 230 g, depending on the strength characteristics
within the assumed ranges given above." Then it states "these models apply
to members not directly impacted by debris."
The lesson is that one
can get into serious trouble straying from one's area of expertise. Regardless
of whether its Jones or Ryan or Woods or Greening.
Now perhaps Dr Greening
should have looked at Appendix C of the above linked report. It's
titled "Debris Impact Tests of BLAZE-SHIELD DC/F Sprayed Fire-Resistive
Material".
It says "tests were performed to provide evidence regarding the
assumption that, withing the debris field created by the aircraft impact into
WTC 1 and WTC 2, the SFRM used for thermal insulation of structural members
was damaged and dislodged." As far as the tests are concerned, the report
states "the impact kinetic energies from the projectiles were significantly
lower than those from actual impacting debris in the WTC towers due to
differences in size (mass). However, when the impact kinetic energies were
normalized by the impact area, the impact conditions used in the tests
approximated those in the towers ...".
The report concludes that "based on
the observations made in the ballistic impact tests, the SFRM was dislodged by
direct impact with solid objects that had a kinetic energy per unit impact
area approaching 10^^4 to 10^^5 ft lb/ft^^2 (10^^5 to 10^^6 J/m^^2). In
addition, SFRM that was not dislodged after the debris impact lost its
adhesion to the steel surface in all but one test. The SFRM on the steel plate
was dislodged upon impact of the projectiles, except for the ballistic impact
at a 60 degree angle to the plate. ... snip ... The tests results demonstrated
that there was dislodgement of SFRM at locations subject to direct debris
impact. ... snip ... In the WTC towers, where the debris fields were larger
than the dimensions of steel componentes (i.e., such as trusses, beams, and
columns), these testes show that SFRM would have been dislodged for a wide
range of debris sizes and speeds. The test results support the assumption
that, within the debris field created by the aircraft impact into WTC 1 and
WTC 2, the SFRM used for thermal insulation of structural members was damaged
and dislodged."
Regardless of what Dr Greening says or Mark believes ...
Nevertheless, some steel appears to have melted in the WTC
prior to the collapse of the buildings.
This is not
proven. Not by a long shot. As I've demonstrated in several earlier threads.