South Tower Top Section Lean

[ozeco41]

...I do however remain firm at this stage with the observation it is the upper east wall ejecting out and becoming visible part way through collapse. According to the gif used, for the object to be from the lower section, it would have to be remaining relatively stationary while the upper section just 'slides' in behind it for the beginning seconds of collapse. This just seems highly unlikely to me. Truth of the matter is, behind all that dust, we can only guess what is going on, however it seems far more likely to me that it is the east wall of the top section falling off....

Good for you to stick to your guns.

But whilst we are running our various forms of "personal incredulity" I remain firmly convinced that femr2 is right.

...That purple line shape comparing bit seems flawed in my opinion. The entire building was made up of those prefabricated sections of jigsaw like spandrels, drawing a purple line over some of them and saying 'it looks like this bit here' does not prove anything at all. I could just as easily draw a purple outline over a random part of the top section and say 'minus these two parts here, it's identical!'. Not very conclusive in my opinion.

Have you examined the totality of Major_Tom's research into the break up of perimeter panels and what bits landed where and how they fell with whatever rotating or flipping in mid air? Taken overall I find it very persuasive. You may not agree but it is worth a look. M_T or femr2 can give the links. I'll see if I can find them also.

You are probably right to express scepticism - but personally I would not be confident enough to claim he was wrong based on little more than a "gut feel incredulity".

 

[cjnewson88]

*at this stage meaning I'm still going through Tom's info

These were observations of mine, they were not concrete, opinions are always open to shifting, I'm simply offering another possibility.

 

[ozeco41]

*at this stage meaning I'm still going through Tom's info

These were observations of mine, they were not concrete, opinions are always open to shifting, I'm simply offering another possibility.

I fully support your position on those points.

BTW I edited my post and we have crossed - it shouldn't matter.

 

[cjnewson88]

Just reading through this section. I wasn't aware of the large reinforced area below the failure point. This would go to explaining how that section remained in place during the initial collapse of the top section. Looks like I may have to concede defeat

 

[femr2]

the top section does not begin to move downwards before it tilts

Splendid.

however I will stick with the obvious that the tilt was in sync with a downwards motion, even if that downwards motion is a result of the tilt itself, there is still a downwards action occurring.

If you mean downward motion of all four corners...ie post-release...no. Release was a bit later on, but ho hum. As I said I'll dig out trace data and present inter-corner behaviour in visual form.

I do however remain firm at this stage with the observation it is the upper east wall ejecting out and becoming visible part way through collapse.

Not splendid, though "at this stage" is good.

It really is the lower East perimeter. I've tracked it down to individual and specific wall panels...

According to the gif used

Dozens of videos inspected in great detail are the basis of the assertion, not a quick eye-ball at a singluar GIF.

Can I suggest taking some time scrubbing through your video collection in HuffYUV format, enabling you to build a much clearer and accurate mental picture of the motion involved ?

for the object to be from the lower section, it would have to be remaining relatively stationary while the upper section just 'slides' in behind it for the beginning seconds of collapse

That's right, though it's obviously separating the East perimeter from the OOS flooring quite efficiently (which we can also see as descent progresses)

This just seems highly unlikely to me.

Nevertheless the upper East perimeter does indeed travel behind the lower East perimeter, until around the level of the "knuckle", at which point the lower East wall is rapidly ejected.

Truth of the matter is, behind all that dust, we can only guess what is going on

Incorrect. Fairly tedious and laborious observation from multiple angles can allow fully qualified assertion.

It is the lower East facade...

Watch until your eyes bleed

however it seems far more likely to me that it is the east wall of the top section falling off.

It's not.

That purple line shape comparing bit seems flawed in my opinion.

It's not perfect. Some visual cueing only.

The entire building was made up of those prefabricated sections of jigsaw like spandrels

I know. See rendered image above.

drawing a purple line over some of them and saying 'it looks like this bit here' does not prove anything at all.

Prove, no. Assist in allowing you to "see the wood from the trees", hopefully.

I could just as easily draw a purple outline over a random part of the top section and say 'minus these two parts here, it's identical!'.

No, that would be pretty stupid.

Not very conclusive in my opinion.

Unfortunately your opinion is/was wrong on several points within this thread.

Again, I'll dig out additional information for you, as it is the lower East perimeter being ejected.

ETA: "Just reading through this section. I wasn't aware of the large reinforced area below the failure point. Looks like I may have to concede defeat"

There's no "defeat". No battle. I'll still dig out WTC2 corner trace data for completeness.

 

[ozeco41]

...ETA: "Just reading through this section. I wasn't aware of the large reinforced area below the failure point. Looks like I may have to concede defeat"

There's no "defeat". No battle. I'll still dig out WTC2 corner trace data for completeness.

Agreed. It's a good point to remember.

 

[ozeco41]

Just reading through this section. ...

It is impressive work IMO. Hence my disagreement with those who dismiss Major_Tom and others on the spurious grounds that the are, were, or may have been "truthers". If the research is good it is good independent of what position the author holds on scepticism.

It is similar in my opinion to those who call for peer reviewed papers OR proof of PhD as excuses to avoid the reality that facts have been presented. If the facts are true they are true independent of author qualification or level of review. Conversely if the facts are wrong they are wrong despite those "safeguards".

 

[cjnewson88]

It is impressive work IMO.

It is. I didn't even know it existed

 

[ozeco41]

It is. I didn't even know it existed

I've been raising the wrath of some JREF members by praising the work of femr2 and M_T - mostly M_T because his stuff has helped me a lot. e.g. the perimeter peel off studies I regard as the definitive rebuttal of all those crazy claims that heavy beams were thrown 5-600 feet by explosives. The "peel off" mechanisms described by M_T show how those long range beam "throws" are simply explained as "bowling" including the various spins that Shane Warne would be proud to own.

Still I don't expect a Kiwi to agree with an Aussie on Cricketing analogies... BTW I'm 60/71 Aussie, the remaining 11/71 Pommie which further confuses the cricketing loyalties (Not true, the cricket loyalties are 100% Aussie - my local street corner newsagent, where my kids earned their first pay delivering newspapers, was a chap called Roger Waugh. He had a few sons who played cricket when not selling newspapers.)

...nor do I expect US members to even know what we are talking about..

BUT those beams were thrown 5-600 feet by "slow bowling with a variety of spin"

AND anyone on this JRE Forum or the911Forum will know that I have expressed and explained strong disagreements with M_T on some aspects of his presentation of his claims. But never directed at his technical research. Or femr2's by the way - and the technical stuff has involved both as contributors. My agreements and disagreements with Major_Tom would make a study of their own....but not here in this thread

 

[cjnewson88]

The "peel off" mechanisms described by M_T show how those long range beam "throws" are simply explained as "bowling" including the various spins that Shane Warne would be proud to own.

Still I don't expect a Kiwi to agree with an Aussie on Cricketing analogies...

While the all blacks are doing a lot better than the black caps, i'll pretend I have no idea what you're talking about

My agreements and disagreements with Major_Tom would make a study of their own....but not here in this thread

May as well, following my rather embarrassing intellectual ass kicking, this thread isn't good for much else

 

[ozeco41]

While the all blacks are doing a lot better than the black caps, i'll pretend I have no idea what you're talking about

Touché

...May as well, following my rather embarrassing intellectual ass kicking, this thread isn't good for much else

Overall it's been a good thread. We can stop posting now.

The ozeco v Major_Tom areas of disagreement go to aspects of his logic and style. I have attempted several times on two forums to assist but, put very diplomatically, our discussions have not progressed.

The thread "Major_Tom Disproves NIST Claims in a Number of Key Areas" is as good a revelation of the issues as you should need. Oystein shares similar opinions to mine and there is variety between our styles of explaining/addressing the issues of concern.

Bottom line is that I have challenged M_T to a one on one discussion on both this forum the 911Forum. The challenges neither acknowledged nor accepted on either forum. So I won't be pushing it. Horses, water, leading and forced imbibing of fluid being the sort of issues which arise.

And let's not misuse this thread by derailing into more details.

Time for me to do some work - just after 0800 over here on the "Western Islands" of NZ where us "strines" live.

Cheers.

 

[jaydeehess]

Oy Vey, this again. Yet another windmill for AE911T to tilt at?

The pivot point is all but immaterial as no matter where it is, it is not going to survive for long. If one had a hinge between two pieces of plywood and set them up vertically the top one would rotate until it was parallel to the other. However that's only because the hinge itself is a real hinge and not a length of steel that is being compressed on the inside of the angle and in increasing tension on the outside of the angle, it is not subject to massive loads that it was never designed to take.

Once the hinge/pivot breaks down, and this will occur fairly quickly as columns buckle or snap, the entire mass will fall with it Center of Mass moving straight down. Any angular momentum it has built up while pivoting will now be converted to angular momentum with the CoM as the center of rotation.

Unless the mass has been rotated such that the CoM is now outside the footprint of the structure then the greatest percentage of that mass will impact the lower structure. There will be NO column on column impact, all mass within the foot print of the next lower floor space will impact that floor pan with a huge dynamic force that will collapse that level which only adds to the falling mass and load on the next floor down, etc., etc., etc.

Is this a difficult concept?

ETA: I see that this thread has run its course,,, oh well I believe my point still stands.

 

[ozeco41]

Oy Vey, this again. Yet another windmill for AE911T to tilt at?...

I don't see where AE911 comes into this thread...BUT they may be desperate.

...The pivot point is all but immaterial as no matter where it is, it is not going to survive for long...

Sure - but the discussion is about what happens in the period which is "not going to survive for long..." So a discussion about details NOT the big picture. It probably wouldn't interest those who are only interested in the end point but it is a valid interest for those who are interested. Notwithstanding that bit of circular logic.

...There will be NO column on column impact, all mass within the foot print of the next lower floor space will impact that floor pan with a huge dynamic force that will collapse that level which only adds to the falling mass and load on the next floor down, etc., etc., etc.

Is this a difficult concept?...

Not difficult at all. It has been explained yet again in full 3D colour and multi-channel sound over on the "Can 15 floors crush one floor?" thread mainly for the benefit of Doubting Tony Sz.

OH, alright, prune out my hyperbole. Substitute "It has been explained yet again in comprehensive reasoned arguments put by ozeco41, Oystein and femr2...." with encouragement,support and agreement from several other members. Then replace the "Doubting Tony ...etc" with "Determined denialist in face of and ignoring all reasoned arguments including visual evidence of his faulty reasoning Tony ...etc"

The key point to understanding "NO column on column impact" is IMNSHO the simple fact that once the top block started to fall all columns had failed (or were in the process of failing) AND their ends were already past each other (or were heading that way) Both the disclaimers needed to keep my logic pure. They allow for highly unlikely bits of "yes butting" and are easily explained for Doubting T...er "Thomases" - if said DT's are prepared to listen. BTW it is interesting how many people miss that point - with the "top Block" falling it is already too late for axial end for end contact. (And, once again, with an easily disposed of minor disclaimer.). Additional argument from femr2's observations that the outer perimeter did in fact miss. But visual evidence is also ignored by certain doubters.

...ETA: I see that this thread has run its course,,, oh well I believe my point still stands.

Yes And Yes - with a few minor nit-picks not worth worrying about.

 

[femr2]

There will be NO column on column impact

Whilst I agree that perfect axial column-column impact is impossible, it's possible that some columns may come into partial contact with others (or parts of themselves). Not at all like the scenario painted within TMJ.

all mass within the foot print of the next lower floor space will impact that floor pan

Not all at once, and not all at the same time. Different places at different times.

with a huge dynamic force

Multiple smaller.

that will collapse that level

Too simplistic wording imo, but successive OOS region support failure, yes, with, in practice, multiple separately propogating "crush fronts" closely matching the OOS region "zoning".

which only adds to the falling mass and load on the next floor down, etc., etc., etc.

Again, too virtual and simplistic. In reality it is highly probable both theroetically and by observation that only a portion of mass descending within the perimeter was involved in propogating ROOSD. The rest trailing behind a-bumpin' into other stuff the first "crush front" didn't dislodge.

Is this a difficult concept?

No, but stated in a rather 1D "block" type manner still.

 

[ozeco41]

Whilst I agree that perfect axial column-column impact is impossible, it's possible that some columns may come into partial contact with others (or parts of themselves). Not at all like the scenario painted within TMJ...

Which is the main reason I include the disclaimers in my otherwise simple claim.

A couple of scenarios to explain:
1) If a columns or a few columns came into end for end contact the overwhelming falling weight would result in "instantaneous" buckling and back into all ends missing. The flexibility of the structures would not prevent that buckling and I use "instantaneous" for brevity of writing. More wordy explanations if needed so nobody ask please.

2)The most likely place for such brief end for end IMO being in the initiation zone (which is where we are anyway in case we forget) with columns that could have broken leaving some separated ends with vertical space between them. (Again a simplified explanation...please don't ask etc )

3) At that initiation stage and more so as progression works down the core (but not the perimeter) there could be opportunities for glancing contact between falling bits and "columns which are leaning out of vertical". Or out of vertical columns falling on other bits including out of vertical....you will get my drift.

So your proviso femr2 is what I have in mind with my "disclaimers" against the simple scenario. But easily explained.

And "TMJ" is pure fantasy based on a false concept of how the collapse transitioned from "initiation " to "progression" PLUS arse about sequencing in both physical events and timing of Tony's base premise that something is falling "from above" to "later" land on something below.

The confusion at least in part probably resulting from his pre-determined belief that bits of columns had been removed by CD cutting --- then his need to "prove CD" which led him into the circular logic aspect of TMJ where he in effect proves his initial assumption.

Simple as that methinks.

 

[Oystein]

I see with a bit of sadness a gulf between Dave Rogers and femr2 that ought to, and could easily, be marrower.

And I think much of it is (besides learned and practiced animosity) quite simply about the semantis of the word "release".

In Dave's mind, "release" is the approximate point in time when the center of mass enters the period of sustained dropping at increasing velocity greater than that which results from creep and localized failures.
In femr's mind, release is the moment after which all sub-assemblies across the floor above crush zones are moving down - from corner to all corners.

Dave's release may be a little earlier.

Obviously, the tilt implies absolute and never stopped descent of the center of mass, so by that definition, tilt can't possibly start before release.
But that cannot reasonably be what the OP asked about - because in that definition, tilt is logically tied to descent: if tilt, then descent (not necessarily vice versa).



If you want to think about tilt and drop as independent quantities, I think femr's approach makes slightly more sense.


Best would be if we knew where the center of mass is, and could track its movement. But that is practically impossible.

 

[ozeco41]

I see with a bit of sadness a gulf between Dave Rogers and femr2 that ought to, and could easily, be marrower....

I had similar thoughts but couldn't see how to address the issue.

...(besides learned and practiced animosity)...

..that is the hard bit given that the mechanism is both two sided and based on poor foundations. You and I having some experience of both sides whether for better or "not so good".

...If you want to think about tilt and drop as independent quantities, I think femr's approach makes slightly more sense....

Yes. But the whole discussion seems to have a few doubtful premises mixed in among the pearls. My simplistic view being that:
1) If one side of the damaged zone crushes it will lower the "top bit which I won't call a block even though I don't think it is rigid"; AND
2) One side going down will:
3) cause "dowmward movement" of parts of the top bit;
4) at the same time causing rotation of the whole top bit;
5) with both of those effectively just orthogonal vectors of the same movement; AND
6) the balance of which parts of the whole moved where/how far depending on where the hinge was; AND
7) the flexibility of the lot; AND
8) all of the above most likely varying as time passes; AND
9) including movement of the (virtual) hinge...
10) and I had the arrogance to call this "simplistic"

and there are probably a few more but those will do for starters.

Which is why I prefer to stay with the big picture logic when that dominates rather than go into details which as often as not can only be conjectures etc etc...

...Best would be if we knew where the center of mass is, and could track its movement. But that is practically impossible.

Which says most of what I just said but with more efficient usage of words than my verbose legalistic pedantry allows me.

 

[leftysergeant]

Okay, I am not sure Iam following all of the previous descriptions of the motion that we see going on. Correct me if I am wandering into undefended territory here.

Look at the tower from an angle that put the hot spot where the molten metal appeared on the left of the screen.

When collapse begins, the bottom edge of the top block moves toward the camera, very slightly, in the scale which we see, but, given the size of the towers in real life, this could be a matter of feet. Given that the face we are looking at is on the up-wind side, it may be safe to assume that there are fewer floors damaged by heat there. Most of the damage to this face is ballistic in origin. The most heat would be down-wind, thus more floor trusses would have failed due to sagging. The top block is, therefore, heaviest on this side. The columns to the left would have sustained the most damage in the initial crash, and those to the right almost no damage. They were also sheltered from the most direct heating.

I am now thinking of the video we have often seen of a massive I-beam bent into a horseshoe shape at obviously quite high temperature. From this, I have drawn a mental picture of the top block not being dropped abruptly on the lower, but being set down on it as the columns sagged, rather than snapped.

This sagging would, obviously, disalign the ends of the columns at the point of failure. Based on my conclusion that the side of the builoding toward the camera weighed more, it would seem logical that the upper columns would have been pulled toward our point of view. Once the upper columns are set in motion, it follows that they would continue to some degree, for a time, in the same direction.

Now we have the heavier portion of the descending block pulling the other side of the building over a pivot point across the tops of the standing core columns. This puts a strain on the undamaged columns to the right side of this face, so that they break as well.

It is clear to me that the vidoes of the event show the top of the falling block moving slightly toward the failure point until well into the process of collapse. The less robust upper core structure is breaking itself to pieces on the lower, more robust core. (This also damages the lower core to some extent, causing it to be vulnerable to the vibrations and resonances set up by the pummelling of ther collapsing floors and the upward rush of air turbulence created when the floors collapse and air can find exit only out to the sides or up the core.)

Anyone using the word "symetrical" to describe the collapse is pulling evidence out of his underwear.

 

[femr2]

Anyone using the word "symetrical" to describe the collapse is pulling evidence out of his underwear.

The word "symmetrical" appears only once in this thread, well, twice including my quote from your post above

 

[Dave Rogers]

I see with a bit of sadness a gulf between Dave Rogers and femr2 that ought to, and could easily, be marrower.

And I think much of it is (besides learned and practiced animosity) quite simply about the semantis of the word "release".

I appreciate your concern, and I think you're probably right on most of it, though in the great scheme of things it's no major tragedy if two people continue to bicker on the Internet. But I think the real disconnect is that femr2 is talking about the fine details of the collapse mechanism, whereas I'm talking about the confused thought processes of the people making the original claim. Going back to the way it was stated in the OP:

The claim by conspiracy theorists is that the top of the South tower leans over, and then seemingly out of nowhere, just begins to fall down through the building instead of falling off the top like "it should".

Although this is prey to accusations of a strawman argument, it's not a bad representation of the way supposed anomalies are commonly presented by conspiracy theorists. In particular, it's very vaguely phrased. It seems to me that this is a mechanism, whether wilful or accidental, by which the claim of an anomaly is supported. Suppose a conspiracy theorist were to say, "Have you ever noticed how the upper part of the South Tower initially appears to rotate about a fixed axis somewhere within the building at or close to the level at which collapse initiates, but then at some subsequent point, instead of continuing to rotate about that point, the otion of upper part of the structure also acquires a downward component?" It would then be a rather trivial matter to point out that this is exactly how a hinge point in a collapsing structure would be expected to behave, even though this is no more than a more precise statement of the original claim. And it's the inability or unwillingness of conspiracy theorists to state their claims clearly enough to allow them to be effectively refuted that I was originally commenting on, not the details of the collapse mechanism.

Of which, I should add, I have no issue with femr2's description. He was simply addressing a very different point to the one I was trying - apparently rather ineffectively, it appears - to make.

Dave