- This topic has 245 replies, 1 voice, and was last updated 4 years, 10 months ago by
.
-
Posts
-
The stiffener plates are relevant to WTC7. I have no desire to defend NIST’s analysis of WTC7’s collapse.
Yes, I’m saying that an emergency demolition was performed on WTC7, on the day of 9/11.
I stress emergency, not “controlled”. A civilian demolition is “controlled” in the sense that the company guarantees to limit the adjacent damage, and will pay compensation should damage exceed those limits. None of this applied post-collapse of WTCs 1 and 2; saving lives became the priority. The fire-fighters were on the verge of mutiny, prevented from searching for their lost comrades in the WTC7 exclusion zone.
Military engineers have repeatedly brought down structures in a matter of hours, behind enemy lines. Similar to 9/11, adjacent damage is not going to spark compensation claims and “control” is not the primary objective. It is true that WTC7 came down pretty symmetrically. Considerable asymmetry in fact occurred, but it was only clear from one of the camera angles, and all the more commonly seen shots make the fall look more symmetrical than it was. The fall also damaged two adjacent buildings; though most of the debris did end up in the building’s footprint, it would have been considered an expensive failure as a controlled demolition.
I think the remarkable symmetry of collapse was a combination of skill, luck, and WTC7’s unusual truss arrangement straddling a pre-existing electricity transformer substation; the “bridge” upon which the core was constructed acted as a convenient way of dropping the core.
I have no interest in defending NIST’s collapse initiation scenario. That perimeter walls bowed in is a matter of photographic and video record, but then so is the early descent of WTC1’s antenna, indicating core failure.
…though I wouldn’t have used the term “confined to”. Damage on 9/11 was anything but confined.
– “the floor system in the twin towers did not take any of gravity load of the building”
Precisely. The floor systems were never intended to take the weight of the structure above – someone needs to ram this home to people like Gage.
Of course when the vertical columns got out of line at collapse initiation, a floor system or two is precisely what would be the next line of defence against collapse. No chance.
– “The North tower collapsed in about 13.8s total which equates to around 2/3 freefall, total freefall being approcx 9.2s for 1365ft. Still way too fast.”
Yes, the internal collapse accelerated at around 2/3 of g, so 1/3 of the entire potential energy of the structure (before collapse) was available for destruction of materials.
Convert that to TNT equivalent and you can see that it was way more than enough.
– “the internal collapse accelerated at around 2/3 of g…”
That’s Chandler’s very good work too; he has a video on YouTube, a shot of WTC1’s collapse from afar, with superimposed descending bars indicating free-fall and the actual progression of the internal collapse front.
No, he isn’t wrong. The aircraft did indeed puncture the “screen netting” (a fact that many Truthers declare impossible, and get away with) and the buildings indeed continued to stand.
Do we know that the buildings hadn’t become overloaded and weakened in use? Floor assemblies had been breached to install entire escalator systems. Massive lead-acid battery backup rooms had been installed. By 2001 nearly every desk probably held an old-fashioned glass CRT computer monitor, unanticipated when the buildings were designed.
I thought the “largest elevator upgrade in history” was WTCs 1 and 2, not 7, but do check if you wish.
Explosives in WTCs 1 and 2’s cores do not help us explain those collapses, because the video record shows that those cores fell only after the floor stacks had torn themselves to pieces and the perimeters had toppled outwards.
Gerry, I’d like to thank you for having kept the discussion reasonably well-focussed upon engineering and physics. I have had many very unpleasant exchanges with “9/11 Truthers” who leap about diverse points eg. as if lack of effective airport security had some relevance to building collapse rates etc., and they have insisted upon insinuating that I’m some sort of pro-war secret agent, repeatedly sniggering amongst themselves.
I am no such thing; I’m an anti-war activist since 2003 and now a member of Extinction Rebellion; I spent ten days last April camping on the Marble Arch traffic island, and for many years I was a volunteer helping Craig with this website. It gets really depressing when some self-appointed gang quip among themselves about how I must exult in the murder of innocents, just because I know when Newton’s laws haven’t actually been broken.
…and when I praise Chandler’s work I am not being sarcastic; sarcastic voice tones don’t survive transcription to text, so I’m not using sarcasm, I’m trying to write as straight as I can. If I find myself lapsing on that rule I hope to apologise and clarify.
Chandler has done painstaking observation and measurement of the video record. His “Smoking Guns” videos are simply misinterpretation – the objects that fly apart in mid-air are spinning, and fly apart due to conservation of angular momentum. The objects that suddenly change direction seem to have been struck by other falling debris; you can even make out some of the impinging objects.
The whole matter of the Twin Tower collapses has become highly polarised and contentious with nearly all participants taking one side or the other and accusing their opposite numbers of ill intent; an entirely inappropriate environment for detached and rational analysis. Let’s try to work together to correct that as best we can.
Peter Ketcham, a former National Institute of Standards and Technology (NIST) employee, explains in the video linked below that he had always been very proud of working for NIST (as a computer scientist/mathematician) and believed at one time that NIST had an established reputation for doing “research of the highest integrity”. He was employed by NIST at the time the investigation into the WTC collapses was ongoing, but was not involved in that research himself.
He describes in the video how he became very disillusioned with his former employer when it was drawn to his attention that NIST had apparently made some quite egregious errors in the investigations into the WTC collapses. For one example that springs to mind, he found that NIST was quite clearly misleading the public when they boldly insisted computer modeling of their proposed WTC7 collapse initiation and the following couple of seconds closely matched what was seen in the actual videos of the event when it clearly did not.
Furthermore, he questions NIST apparent obsession with only identifying an initiating event or failure that could possibly start a collapse process but then ignoring any investigation into the subsequent behaviour of the falling structures, as if that was entirely inconsequential to producing a well rounded and comprehensive report of the three most significant structural failures in history.
Stand for the Truth: A Government Researcher Speaks Out | 9/11 Evidence and NIST
https://youtu.be/GvAv-114bwMIs not the point of using namothermite that it will cut the steel for you, obviating the need for disc cutters?
1. Controlled demolition does not break Newton’s laws. It allows building collapse to proceed within normal laws of physics.
2. Dozens and dozens of first responders reported contemporaneously a series of loud bangs indicative to them of explosions at WTCs 1 and 2. Do you immediately rebut their testimony as wilfully inaccurate?
3. Expert demolitions professionals conclude that WTC7 collapse was entirely consistent with controlled demolition. Do you regard those specialists as lying incompetents?I will not get into the scientific rigour of Extinction Rebellion, but suffice it say that you have a job on your hands to convince me that you are scientifically rigorous.
FYI, MI5 et al put me under surveillance for strong opposition to Iraq war amongst other things. It was very intrusive surveillance. I have never worked for an arms manufacturer, in the oil industry nor have I ever supported Likud, Verwoerd et al or US imperialism.
1) After collapse initiation, the collapses of the Twin Towers as recorded on many videos proceeded within the normal laws of physics, without any need for assistance by explosives.
Indeed, explosives would have noticeably disturbed the natural motion and destruction. Further, observation of the wreckage shows that the perimeter broke into sections by breakage of the bolts at the box section ends, not by melting or explosion. Dust was produced predominantly in the final crush of the internal collapse hitting ground, not evenly throughout collapse as the proposed sequenced detonations would have done.
2) I regard that testimony as reasonably accurate – after any incident, testimony of different witnesses shows considerable variation. But nearly all such reports concern loud bangs before and up to the time of collapse initiation. There are not widespread reports of percussions in a timed, accelerating sequence during collapse progression.
3) You seem not to have read what I have written; I wrote that I agree with the late Danny Jowenko, the Dutch demolition expert. I suspect that WTC7 may have been subjected to emergency demolition, decided upon and executed shortly after the collapses of the Twin Towers, so that the fire-fighters could continue rescue operations in the WTC7 exclusion zone.
My disagreement is one only of semantics; this could not be called a controlled demolition, because the word “controlled” in the term “controlled demolition” refers to guarantees of limiting the extent of adjacent damage. This would have been neither reasonable nor possible in the chaotic environment of 9/11; just for starters, WTC7 was on fire.
Sorry, this is a reply to Rhys Jaggar’s comment #46979 of September 7, 08:45.
The video Stand for Truth has the clearest video images of the Twin Tower core remnants, both during and immediately after collapse, that I know of anywhere. It clearly confirms that the cores stood longest, after the internal collapse had stripped out the floor assemblies and the perimeters had consequently tumbled outward. This rules out destruction of the buildings by initial explosive segmentation of the cores.
NIST made many errors and frequently returned sloppy work, but their statement that after initiation, rapid global collapse became inevitable, is true. It is true by a very wide margin. This is why there has not been a massive outcry from the global physics and engineering communities.
Clarke: forest / trees. Don’t lose sight of the forest when examining the precise texture of a tree’s bark or the pattern of a leaf. Not calling for intuitive guess work but one part of the brain should scan the bigger picture and then decide where to allow the forensic part to look to examine the detail. The bigger picture: novice pilots for towers 1 and 2; no plane at tower 7; and then consider Bill Biney’s statements on the change of policy from targeted to bulk acquisition of domestic and world wide data, which preceded the event in question.
Sorry, I replied to Rhys Jaggar, but in the wrong place, below. Those wishing to reply on this subtopic please continue there, to preserve continuity.
fwl, I am aware of and have considered all those matters. My big picture assessment is that the attacks may well have been a Gladio B operation exploiting proxies, either broadly intentional, or something certain parties permitted to get out of hand. I look more to NATO and the military-industrial-secrecy complex than the US government and its (thoroughly penetrated) agencies.
My assessment of the various collapse dynamics does not conflict with this.
A thermite substance might explain the “attacked” steel that FEMA found in the WTC7 debris, which NIST notably failed to mention despite FEMA stating that it required explanation. Thermite would also be easy to make at short notice from commonly available substances.
Ok – noted.
Even descending to less clandestine possibilities, we have decades of US collaboration with and exploitation of Wahhabist extremists, emanating primarily from those Western/Israeli allies the Gulf Monarchies, primarily Saudi Arabia.
I recall asking someone to look up WTC7 on their internet phone and watch it fall and they couldn’t accept what they saw as evidence of controlled demolition. And that’s the problem, people know if they allow a bit of truth to enter their mind-set the whole story falls down, which they fear to allow, as what do you do with such information?
You’re assuming that they’re more attached to a particular story than you are; controlled demolition can indeed be ruled out, and you need to question your own acceptance of that catch-phrase.
I assume that you’re not David Chandler.
- The topic ‘Engineering Prof releases draft report on 9/11 collapse of WTC Bldg 7 in NYC’ is closed to new replies.