The 9/11 Forum

Dr. G wrote:The energies I have estimated are to break all the perimeter column splice bolts on one floor. All A325 bolts are assumed to be 36 ksi steel.

Now we know the perimeter columns in whole horizontal sections of the impact zones of both towers bowed significantly in the moments before the total collapses.

I'm afraid we do not know that. We have zero evidence of such behaviour, other than inference.

I fail to see how cutter charges made columns bow like that.

What bowing ?

If any posters believe otherwise I would like them to explain how these charges worked!

Do you mean the charges which inititated descent, utilising the requirement to sever 96-98 core, blow the roof ( confirmed by radical increase in smoke ejecta ) closely timed with charges in upper and lower mechanical floor regions to ensure that gravity did it's thing, followed by...... Booom, boom, booom. Three charges synchronised to ensure that the central core did not remain upstanding, but instead descended figuratively into the basement. Though in practice it actually went....boooooom, and ended up in 36ft sections around ground zero.

As for thermite on the perimiter columns, it would have been clearly visible in the large areas where the columns bowed

Any charges would be directed towards the core. There would absolutely no rational reason to think that any of the actual destructive implementation would be visible to the public in the slightest (other than the obvious requirement to totally mash-up the mechanical floor regions)

, but was not seen; so we can rule out thermite, super or nano, as well.

No, we cannot. Not until we have a sample of an appropriately handled sample to analyse.

(As I have said before, proponents of CD theories never offer anything but hand-waving fantasies about how the alleged dirty deed was done, .... and yet they are so quick to offer criticism of "natural collapse" theories!)

I have offered many "old skool" questions, which have been ignored and remain unanswered, the simplest of which is the identical nauture of the damage to the mechanical floor regions on impact of "flight "175" (N175F) and the "collapse" of the building and the identical nature of the debris ejecta to the lower mechanical floor region.

As time is critical, gloves off...

David B. Benson wrote:

femr2 wrote:

Dr. G wrote:We have zero evidence of such behaviour, other than inference.

With all due respect, this is false. We have the evidence of the south wall of WTC 1, both visually and the NYPD helicopter observer reports. The video shot of the south wall was, of course, several minutes before collapse commenced. The NYPD helicopter observer, however, reported he could see the buckling of the western portion of the south wall (or the southwest corner) about 2--3 seconds before reporting that collapse had commenced. That is direct evidence and confirms the inferences described in the WTC 1 Collapse Initiation thread.

... the roof ( confirmed by radical increase in smoke ejecta )

WTF? I just see some additional smoke coming out the ventilators from the uppermost mechanical floors, due to increased internal air pressure. That's all it is.

Would you care to let me know where you are quoting me from, right now. Not something I have said, for absolute kin sure.

David B. Benson wrote:

femr2 wrote:Would you care to let me know where you are quoting me from, right now. Not something I have said, for absolute kin sure.

Two posts back. In quoting you, somehow an extra Dr. G crept in. I went back to my previous post to correct that and so the quotations from your post should now be correct.

Apologies for the error.

No probs. What I'm trying to highlight is the difference between gradual 'bowing' over an indeterminate period of time and almost instantaneous bowing due to initiation, which was unclear from the statement reposnded to. (I have calculated zero structural defomation of the facade in any direction prior to initiation)....(WTC2, yes. Instant slight deformation upon impact. WTC1, no. Zero.)

I do not agree that the rapid increase in smoke volume and the initiation of the descent were totally unrelated events.

I am sure that with additional scrutiny, over an extended viewing period, that there cannot be any iference that the increase in volumous smoke ejecta and the rapid onslaught of descent are unrelated.

Especially given the location of the smoke ejecta and the southerly tilting of the cap...totally inconsistent with the damage caused by impact, which really should have caused a northerly tilt and mode of failure (if any....).

Add: We have previously discussed the NYPD viewpoint, with their own photographic evidence, from their absolute point of view and have still seen nothing to validate their 'at the scene' opinion. My view is that analysis of their photographs is significantly more valid than the heightened situational opinion at the time. No tilt was evident in my analysis. Additionally, no deformation of nearby structural members was evident either.

If you want me to show the contrasting evidence pointing to immediate WTC2 deformation upon impact, no problem. I can find no similar deformation for WTC 1.

(No probs with the topic drift btw. It's all in the right direction)

David B. Benson wrote:

femr2 wrote:What I'm trying to highlight is the difference between gradual 'bowing' over an indeterminate period of time and almost instantaneous bowing due to initiation

Go back to the WTC 1 Collapse Initiation thread to see the actual data from the antenna mast. The transition for gradual to much less gradual is as smooth as could be. What was essentially instantaneous was the fracture of the west wall, as reported by Major_Tom. By inference, the same happened to the east wall.

I assume you are aware of the time-frame of the smoke ejecta mentioned, and the evidence available to confirm any form of bowing ? If not, we are talking around 10s-15s prior to initiation, not minutes. Does this alter your viewpoint ?

I do not agree that the rapid increase in smoke volume and the initiation of the descent were totally unrelated events.

I don't either. But the increase in smoke volume is simply due to compressing air as collapse progressed, forcing some additional smoke out the HVAC ventilators at the uppermost mechanical floors.
Do note that OneWhiteEye's measurements of the antenna tower dish and, further up, dark band are subpixel and good within centimeters. There is no evidence of anything but a very good fit to the B&V crush-down equation. Ergo...

Have to refer the honourable gentleman to my previous response...

... the southerly tilting of the cap...totally inconsistent with the damage caused by impact, which really should have caused a northerly tilt and mode of failure (if any....).

However, the breeze that day blew through the tower and fanned the fires towards the south side. Additionally, one of the wall panels was knocked out by the impact and there was also a hole through the SW corner. The accident of the location of combustables, determined by NIST's analysis of videos to have the history of fire progression, meant that the south side, towards the west, had the worst of it.

As far as I am aware, the sudden appearance of fire around the initiation zone, around the west side is unexplained....and is a topic of much discussion.
Could you elaborate ?
(Surely the wind would have 'fueled' fire on the east side...)

David B. Benson wrote:

femr2 wrote:If not, we are talking around 10s-15s prior to initiation, not minutes.

Oh, that early.

Yes. Other points moot in context of rapid increase of smoke ejecta and correlation to initiation of descent.

David B. Benson wrote:

femr2 wrote:... rapid increase of smoke ...

I take this as rather without value all by itself. Maybe from the floor 104 fire? Yawn.

... correlation to initiation of descent.

Correlation is not causation. In particular, there is no evidence of the antenna tower even beginning to slowly tilt/descend until about 2.5--3 seconds before the formal t0. That does not mean that it did not, just that the available evidence, although of very high quality, is not accurate enough to support such a conclusion.

Without yawning, I suggest the ony route (given the video challenged) is for me to provide clarification of the time-frame of the increase in smoke ejecta I am referring to. Bear with me. 4am UK time. Will post inline video of relevant detail after zees.