Moderated WTC 1 features list, initiation model / WTC 2 features list, collapse model

[Major_Tom]

TFK: "MT,

I asked "where is the same antenna tilt vs. frame no. analysis of video taken from camera looking at WTC1 closest to 90° (either direction) from the Sauret video?"

Tom, so as to not waste time, can you tell me the video clips available to study WTC1 collapse initiation? There are only a few good ones and they have been around for a while. Anyone who has been studying the initiation from multiple viewpoints knows what they are. Your question shows me you don't know.

Don't you think you should at least know that before asking?


............

Reactor Drone, the Sauret viewpoint is looking up at the building. Did you use this geometry?

http://img404.imageshack.us/img404/4391/sauretrelations.gif




Here is the quantity a-b over the first 3 degrees in meters. Left graph, blue line.

http://img46.imageshack.us/img46/5084/image00000x.png

So basically, the question is one of how accurately can this be measured. This may be the best place to look at what accuracy is possible:

http://www.sharpprintinginc.com/911...op=view_page&PAGE_id=146&MMN_position=322:322

 

[femr2]

It's been two mornings.
Where's the response.

I'll get there, don't worry. The nonsense yesterday sapped my available time. You in a rush ?

 

[femr2]

The building section rotated about 8 degrees and then fell vertically.

Just to give you something to think about...

Note that the NW corner is visibly descending from half way through the short clip. Trace data can show more accurately the point at which vertical motion begins.

I've used this view as it's relatively near to West-on. Quality is a bit grotty, but the best available from that viewpoint (NIST Cumulus DB).

I'll probably apply some annotation and measurement (though your eyeballs are quite sufficient in this case), but, come on, suggesting that *The building section rotated about 8 degrees and then fell vertically* is simply an acute case of NISTitis.

 

[Grizzly Bear]

I'll probably apply some annotation and measurement (though your eyeballs are quite sufficient in this case), but, come on, suggesting that *The building section rotated about 8 degrees and then fell vertically* is simply an acute case of NISTitis.

From the same post you responded to:

Until the rotation reached at least 8 degrees, the building section was rotating and falling

NIST used “rotation” and “fall vertically” as two separate stages. The north wall was rotating to 8 degrees and falling before it began to fall vertically with no rotation.
The start of falling vertically begins when rotation stops.

Although a minor "quibble," the rotation didn't really "stop." For both towers the maximum values were measured before the upper sections were totally obscured by the dust. Haven't looked directly at the NIST documents in a while but IIRC they explicitly mention that the values were measured before the obscuring made it impossible to obtain visual measurements.

 

[W.D.Clinger]

Just to give you something to think about...

[qimg]http://femr2.ucoz.com/CNN_Aircheck_Eric_Letvin_Cli24.gif[/qimg]

Note that the NW corner is visibly descending from half way through the short clip. Trace data can show more accurately the point at which vertical motion begins.

I've used this view as it's relatively near to West-on. Quality is a bit grotty, but the best available from that viewpoint (NIST Cumulus DB).

I'll probably apply some annotation and measurement (though your eyeballs are quite sufficient in this case), but, come on, suggesting that *The building section rotated about 8 degrees and then fell vertically* is simply an acute case of NISTitis.

No. I am not qualified to diagnose your disease without annoying LashL, but my eyeball analysis of the clip you posted already refutes Major_Tom's claim that the tilt was two degrees or less.

Holding a protractor against my computer monitor (the technique recommended by Major_Tom) shows a tilt of roughly 1 degree, probably slightly more, in the plane of the image. By eyeball (the technique recommended by femr2 above), the tilt of the top section is mostly toward me, so the true tilt must be several times (and definitely more than twice) the tilt measured in the plane of the image. That means the tilt must be more than two degrees.

8 degrees seems quite plausible for the true tilt, but I wouldn't argue for 8 degrees on the basis of Major_Tom/femr2's protractor/eyeball methods. BasqueArch calculated 8 degrees using better methods, and that calculation has held up since.

If Major_Tom had a better argument against BasqueArch's calculation than to claim the 8-degree tilt comes after the fairly arbitrary time that Major_Tom had chosen for the initiation of vertical fall, and to mutter darkly about "murder" because NIST and BasqueArch are using the word "as" to mean "at about the same time" instead of "before", then I think Major_Tom would have presented that argument by now.

 

[femr2]

The 8 degrees of rotation is there

Where ? On that GIF ? If that's what you are stating, please show your measurement of such.

but as far as I've read from the NIST this refers to the maximum value that was visible before the upper sections were obscured completely.

It refers to the statement by BasquArch. It's incorrect.

NIST state varying versions of the metric, but this form more times than any other...

Rotation of at least 8 degrees to the south occurred before the building section began to fall vertically under gravity.

...which clearly does not fit what *you have read*.

The south tower was still rotating when it was obscured by the dust

Sure. Irrelevant to the context of discussion though.

and the max value given by the report is that visible prior to obscuring.

The quote I provide from NIST above is particularly specific.

 

[Grizzly Bear]

It refers to the statement by BasquArch. It's incorrect.

You failed to read his post in the first place. I quoted it, looks like you grabbed the initial post before I edited a good 20 minutes ago. Reread his post, he made it quite difficult to "confuse"

Sure. Irrelevant to the context of discussion though.

Perfectly relevant to what I was posting. The tilt of Tower 2 is measured exactly the same way as Tower 1. It's maximum value was measured precisely the same way.

Where ? On that GIF ? If that's what you are stating, please show your measurement of such.

It's not within the time frame covered on the GIF. It should have been obvious to what I was referring considering you responded to the part of the post that gave the context. I have absolutely no idea how you took it otherwise.

 

[femr2]

No. I am not qualified to diagnose your disease without annoying LashL, but my eyeball analysis of the clip you posted already refutes Major_Tom's claim that the tilt was two degrees or less.

Accurate determination of the exact moment that the NW corner began vertical motion is not possible with that clip, nor by eye-balling.

By eyeball (the technique recommended by femr2 above)

Whoa there. I'm only suggesting that eyeballing can confirm that the NW corner is in vertical motion before the upper section has rotated by 8 degrees. I'm not suggesting that that clip can be eyeballed to determine at what specific tilt angle the NW corner released. I think that scope is made quite clear in my post tbh.

As I said, the release point is about half way through the short clip (about frame 25) so bear in mind you're looking at the angle at that point in time, not afterwards. I can specify a more precise frame number by synchronising with Sauret, but it's not really necessary for the task in hand.

I'll be posting my own rotation details fairly soon, to compare with MT's/Achimspoks data.

Given your previous dilligent posts, I have to say that one is rather lacking in detail. This in particular was unexpected...

that calculation has held up since

You're saying it's held up because there has not yet been any direct response to it ? That's hardly *held up* now, is it. It simply hasn't been critiqued yet. I'll certainly be doing so as soon as I can make enough time available.

 

[femr2]

You failed to read his post in the first place.

Incorrect. I've read it numerous times. I'm fully aware of him stating his opinion on what he thinks NIST meant by their conflicting statements. His personal interpretation of NIST statements does not change the meaning of his own statements though.

As you say, rotation did not stop, and any suggestion that it did is incorrect. Any propogation of language making that false assumption is also incorrect.

The upper section rotated by much less than 8 degrees before all four corners had released and the whole upper section was undergoing vertical descent. Before that *release* the NW edge *hinge* had not failed.

Perfectly relevant to what I was posting.

The context of the discussion is at what angle the upper block rotated through before the whole thing began vertical motion.

The tilt of Tower 2 is measured exactly the same way as Tower 1. It's maximum value was measured precisely the same way.

Again, irrelevant to the ongoing discussion.

I'm not personally particularly interested in any discussion about what NIST did/didn't mean. Ther upper section of WTC1 rotated a certain amount before the whole upper section began vertical drop. In this particular bit of discussion, my only interest is in determining and clarifying that angle accurately.

 

[Grizzly Bear]

Also... since I didn't address it before///

NIST state varying versions of the metric, but this form more times than any other...

...which clearly does not fit what *you have read*.

http://wtc.nist.gov/WTC_Conf_Sep13-15/session6/6McAllister.pdf


The pdf reader doesn't want to open the document properly for some reason in my browser so I'll have to provide the relevant text in the final report later. This is as you can see an older document. It states this metric for both towers. There's not much room for confusion here. But since you demand WTC 1:

Tilt reached 8° before view was obscured by dust clouds -grabbed from the google text that appeared below the link. It has the same phrasing for WTC 2 which I know you have a quibble with me bringing up... but it's an FYI more than it is part of the WTC 1 tilt "analysis"

 

[sheeplesnshills]

Going back to the original post......

Any model of the collapse initiation sequence must match the visual record, just as any collapse progression model must match all observables. The OOS collapse propagation model was based on a handful of features from this list.

Does any known collapse initiation model match this visual record? (No).

Questions......

A) Why would you expect a model to match exactly?
B) How could any model match exactly as there are far too many unknowns.?
C) why should anyone care? There are no more World Trade Center Towers so knowledge of EXACTLY how they fell is of no importance or use to anyone.
The lessons that needed to be learned.....better fire proofing, avoiding putting all escape routes in a single core, and that high rise buildings are very likely to fail if hit by large high speed aircraft full of fuel, have been learned.

 

[femr2]

There's not much room for confusion here.

There is no confusion in the slightest. I'm fully aware of the varying scopes which NIST apply to the use of 8 degrees of rotation, and anyone who has followed either this thread or the ROOSD thread knows that over, and over, and over again.

As I said, NIST state varying versions of the metric, but this form more times than any other...

Rotation of at least 8 degrees to the south occurred before the building section began to fall vertically under gravity.

And, yes, they also state...

Tilt reached 8° before view was obscured by dust clouds

Varying forms, and with very different implications.

it's an FYI more than it is part of the WTC 1 tilt "analysis"

Thanks, but I don't need the FYI.

 

[W.D.Clinger]

Accurate determination of the exact moment that the NW corner began vertical motion is not possible with that clip, nor by eye-balling.

You and Major_Tom are arguing about "the exact moment that the NW corner began vertical motion" because that's the only way you two can continue to support Major_Tom's attack on the 8º tilt reported by NIST. In geometry and physics, there is no agreed-upon definition of "began vertical motion". It could mean the beginning of a rotation or other motion that has a non-zero vertical component, or it could mean the instant at which the magnitude of the vertical component exceeds the magnitude of other components, or it could mean some time at which the vertical component begins to dominate other components (which is itself not well-defined).

It all comes down to you and Major_Tom insisting that your favorite arbitrary definition be used instead of NIST's arbitrary definition. That's beyond pointless; it's pathetic.

Whoa there. I'm only suggesting that eyeballing can confirm that the NW corner is in vertical motion before the upper section has rotated by 8 degrees.

You seem willing to admit the possibility that the upper section did indeed rotate by 8 degrees, as NIST and BasqueArch have reported. That's wise of you.

I expect you will attempt to bury the 8 degree tilt under a barrage of data and analysis that purports to prove (and may well prove) that no 8 degree tilt occurred prior to the instant that marks the start of vertical motion according to your arbitrary definition. That's the only way you and Major_Tom can claim victory, and claiming victory appears to be the main point of this charade. One thing has become obvious: This ain't about discovering the truth.

 

[sheeplesnshills]

my only interest is in determining and clarifying that angle accurately.

Why? do you imagine that just because NIST may have got a minor detail wrong that a plane didn't hit the building and that impact and fire caused the collapse?????

This is just mental self abuse.......keep chugging away, all that you and MT are doing are showing that you have lost your marbles.

 

[femr2]

You and Major_Tom are arguing about "the exact moment that the NW corner began vertical motion" because that's the only way you two can continue to support Major_Tom's attack on the 8º tilt reported by NIST.

Incorrect. Determining the angle at which vertical motion began has the direct implication that all vertical support had failed by that time, and so intimitely linked to initiation sequence...the thread topic.

In geometry and physics, there is no agreed-upon definition of "began vertical motion". It could mean the beginning of a rotation or other motion that has a non-zero vertical component, or it could mean the instant at which the magnitude of the vertical component exceeds the magnitude of other components, or it could mean some time at which the vertical component begins to dominate other components (which is itself not well-defined).

Rotation is clearly about the *hinge* of the North face until that fails and vertical descent of the entire upper section ensues.

This allows pretty clear definition and separation of the phases rotation without vertical descent, and rotation with vertical descent. Of course, suggesting that rotation ceased when vertical descent began is foolish.

It all comes down to you and Major_Tom insisting that your favorite arbitrary definition be used instead of NIST's arbitrary definition. That's beyond pointless; it's pathetic.

You're entitled to your opinion, but in mine, you're wrong.

You seem willing to admit the possibility that the upper section did indeed rotate by 8 degrees, as NIST and BasqueArch have reported. That's wise of you.

I imagine the upper section rotated by far more than 8 degrees before it was so mashed-up it could not reasonably be referred to as the upper section. 30, 40 degrees ? The condescending tone is more than unnecessary.

I expect you will attempt to bury the 8 degree tilt

See previous comments.

under a barrage of data and analysis that purports to prove (and may well prove) that no 8 degree tilt occurred prior to the instant that marks the start of vertical motion according to your arbitrary definition. That's the only way you and Major_Tom can claim victory, and claiming victory appears to be the main point of this charade. One thing has become obvious: This ain't about discovering the truth.

You're showing your true colours I'm afraid.

Blinkers off please.

 

[W.D.Clinger]

Incorrect. Determining the angle at which vertical motion began has the direct implication that all vertical support had failed by that time,

I'm sorry, but I'm having trouble imagining any definition of "the angle at which vertical motion began" that could possibly have "the direct implication that all vertical support had failed by that time."

If you could show that a sufficiently rigid upper section's center of mass had begun to accelerate directly downward with instantaneous acceleration g beginning at time t, then that would come close to having the direct implication you mentioned. Even then, there would be alternative explanations, as we have seen with WTC7. In any case, the instantaneous acceleration cannot be measured with enough accuracy to support that particular line of reasoning.

Rotation is clearly about the *hinge* of the North face until that fails and vertical descent of the entire upper section ensues.

This allows pretty clear definition and separation of the phases rotation without vertical descent, and rotation with vertical descent. Of course, suggesting that rotation ceased when vertical descent began is foolish.

Allowing "pretty clear definition and separation" isn't good enough. If your argument rests upon details of your definition and separation of phases, as the argument that might possibly conceivably eventually be presented by Major_Tom evidently will (else you and he wouldn't have spent so much time arguing about the tilt), then you need to state your definitions.

The clearest definitions I've seen so far have come from BasqueArch.

 

[tfk]

TFK: "MT,

I asked "where is the same antenna tilt vs. frame no. analysis of video taken from camera looking at WTC1 closest to 90° (either direction) from the Sauret video?"

Tom, so as to not waste time, can you tell me the video clips available to study WTC1 collapse initiation? There are only a few good ones and they have been around for a while. Anyone who has been studying the initiation from multiple viewpoints knows what they are. Your question shows me you don't know.

Don't you think you should at least know that before asking?

And this is why you clowns are such … clowns.

You may note that you, not me, are the ones that have been "studying the initiations from multiple viewpoints."

A simple response such as "we have these videos from these angles" would be appropriate.

This sort of snarky response is worthy of a petulant 15 year old.
Really improves the quality of the discussion, don't it?

An acknowledgment of the obvious fact that it is impossible to measure 3D tilt from only one direction's analysis would be even better.

PS. I asked "how did you determine the location of the cameras?

No answer yet.

Am I supposed to be able to psychically intuit this info as well…?

 

[Seymour Butz]

Rotation is clearly about the *hinge* of the North face until that fails and vertical descent of the entire upper section ensues.

Rotation around the north face would result in *some* downward movement of that face, even BEFORE they buckle/shear. So then it depends on just how fine a movement you think you're measuring. If your method can see downward movement at ~ 2 degree rotation, but the ext columns haven't buckled/sheared yet, then...... so what? It can't therefore be considered to be falling vertically until they have buckled/sheared off, is what. Semantic arguements be damned.

Tell us when the ext columns can be expected to buckle, using math and the well known properties of steel. FYI, in the 2001 Bazant article IIRC he estimates that the columns in WTC 2 must have sheared plastically at 2.8 degrees, and is indeed seen in videos where the ext columns shear off and fall 'inside the footprint'. Granted, this is a response to the "why didn't the upper part didn't rotate and fall off" hilarity, but the engineering basics are laid out for you to give us an estimate.

Or, tell us when you see them buckle in videos and relate that to your graph of how much downward movement is seen, if any are available of the north side.

Then, tell us how NIST is wrong.

 

[Seymour Butz]

.....can you tell me the video clips available to study WTC1 collapse initiation? There are only a few good ones and they have been around for a while. Anyone who has been studying the initiation from multiple viewpoints knows what they are.

Then multiple views/graphs would be best, right?

Then see some work to correct for the off angle view.

Cuz, well, the ole protractor-held-against-the-screen method isn't exactly confidence inspiring. To the contrary, it reeks of ineptitude.

Don't you think you should at least know that before asking?

Maybe he does in fact know, and wants to see what you did to correct for the off angle view in order to get an accurate estimate. This would need math work, which looks to be your Achiles heel.

 

[Major_Tom]

WD Clinger,

this is a drop curve of the NW corner:

From the drop curve you can extract the slope. It is drawn over the drop curve just not to scale. We can recognize a point at which the velocity takes off rapidly.

I defined this point as a "release event" in the links in the OP. We can also call it the "failure event" or the "velocity take-off point".

The NW corner is the last group of columns to fail. Clearly visible.

By locating the velocity take-off points in different drop curves at different key anchor points on the building, we can see order of failure. That is what I did in some of the links in the OP.

Much, much better than using your "eyeball". Obviously.

In fact, if you try to find the velocity take-off event using your eyeballs and compare it with results by using drop curves, not surprisingly you will find that the eyeball method always guesses the release point too late.

By the time you can see it from that blurry west side view it already happened in reality. Why this is so is obvious if you just think about it.

I guarantee that accurate drop curves in 30fps or 60fps video will beat your eyeball every time.