...I have seen the Shyam Sunder video where he said freefall of Building 7 would be impossible, and he explains why as if he were you! When NIST's final report said that these 2.25 seconds of freefall were consistent with their prior explanations, I believe that was a mistake which explanations from JREF people were unconvincing. You're right about that, in my opinion. And BTW I asked NIST about this problem and never got a satisfactory reply..
Yes Chris, and this goes straight to the heart of the matter. Everyone agreed that a natural collapse could not happen in freefall, even NIST, because as Sunder himself so clearly explained, that would imply the complete disappearance of the structure below/inside the falling top structure.
But this complete removal of structure is possible with incendiaries and explosives, which is why freefall is prima facie evidence for controlled demolition, and it remains so because NISTs computer model confirms that a natural collapse cannot result in freefall.
That NIST tries to ignore its own finding and imply that freefall is consistent with its work is not an example of NIST making a mistake, it is an example of a supposedly scientific institution playing politics, like Clinton saying "I did not have s## with that woman". It is sad that 9/11 did not receive the same level of scrutiny.
...You say, "The problem is not the corners, but the 47 story high walls, which are way too tall and wide to remain rigid without support from the core." But we have the observed phenomena of the two penthouses collapsing (we don't know for sure how far down). I hypothesized that the corners would provide a few flimsy seconds of support to help keep the perimeter wall standing for a short time...
The corners cannot provide support to each other without a solid and stiff perimeter frame between them, and those perimeter frames depend on the support from the core. Without the core the 4 perimeter frames implode inwards. And here is the important bit Chris: As the core collapses down, it pulls on the floor structures which are outside it and in turn they pull on the exterior and drag it down with the core. You are trying to imagine an impossible scenario where interior collapses without pulling on the exterior.
...But if you believe in CD, how do you explain that it sure looks to me like a core collapse preceded the perimeter wall collapse? Seems like there is the same problem whether it's CD or natural collapse. In your CD scenario, how does the wall remain standing even after the core has at least a partial or maybe total collapse (we can't see and assert with certainty)?.
The collapses of the penthouses were only the top one or two floors, but that is only 1 or two top floors of 47. To risk the implosion of the exterior you need two things: 1. loss of core support over several floors and 2. much lower in the building. The 2.25 secs of freefall covered about 100feet which translates into about 8 stories of disappeared structure. The building did not collapse until a substantial portion of the core was dropped in unison, pulling down the exterior as it fell.
...BTW from the very beginning, when I debated Richard Gage in 2011, I said I was not a defender of the NIST Report, but an advocate for natural collapse of the buildings. As just one example, JSanderO has a very different collapse scenario based on his research. I won't say that his is better or worse than NIST's, because again I am no engineer..
Chris, NIST went over and debunked several alternative fire based explanations, including JSOs pet theory, before it arrived at the thermal expansion - girder walk off story. Some people will not listen to anyone and in the end no-one will listen to them either.
..And CTBUH had its suggestions for improvements on the NIST Report. The NIST Report doesn't have to be perfect. The bar for me for wanting a new investigation would be positive evidence of CD, such as tons of thermite in the dust, or CD devices in the debris, or melted ends of the columns, or any number of things for which no evidence has been found, in my opinion. Another bar would be even one of those investigations by Purdue, Hawaii, CTBUH, or any other major organization proclaiming that the NIST Report is fatally flawed. Not one major organization anywhere has said this! Everyone agrees with the basic collapse scenario and questions only some of the details.
Chris, first off this is not at all about NIST "being perfect". The first two criteria when evaluating whether or not a new investigation is needed are:
- Did NISTs work disprove the primafacie evidence for CD such as freefall?
- Are there any indications for misconduct?
We have already seen that NISTs work does not refute freefall as evidence for controlled demolition and that alone tells us a new investigation is needed to find out what could have caused freefall. This does not have to be any more complicated than that. We have also mentioned some of the examples of misconduct by NIST, such as the handwaving of the freefall as discussed above. Other examples of this were discussed a while back when we were going over the thermal expansion story, such as fudged numbers and missing structural elements. I don´t think you realize how serious these kinds of offenses are. A fraudulent report could not only lead to a new investigation but also people losing their licences, people going to jail, and even a new agency to replace NIST.
You talk about the CTBUH not finding any major faults but I think you are mistaking the soft language in those kind of reports. The CTBUH found flaws so fatal to NISTs story that it says straight out it does not believe it at all, not the thermal expansion story, not the girder walk off story, and not the single column story. It tore apart NISTs report, and tt did that without noticing that NISTs model does not show freefall!
It made its comments a couple of months after NIST released its report so it did not have time to really dig into NISTs work, and in particular how NIST came to its conclusions with rather dishonest methods. The CBTUH published its comments long before the revelations were made about fudged numbers, missing structural members etc. And it did not know that NIST would refuse to release input data to prevent scrutiny of its work by independent scientists!
I will let you answer this before going into your bar for a new investigation, that is evidence for CD.