The 9/11 Forum

Major_Tom wrote:
If someone cares to confirm that the piece is associated with special purpose flooring and is not some kind of vertical support, then we have already proven that flooring was connected to the back of the west side peel.

Considering the condition of these pieces, if flooring, we can see they were carried away from the building on the back of the large west face peel before they were hit by the "crushing avalanche" (zone B).

Htf is that physically possible? But first let's try to confirm it is flooring. Feedback?

Speculation, but it looks more like a section of core cross-bracing to me, which would put the htf in capitals:

Or special flooring. The point is that it's cross-section is that of a horizontal support.

To be clear, the interconnected pieces that surprised me the most are:



This photo changes everything I thought I knew about perimeter peeling.


Please help me out here, guys. First of all, what is it?

How about HVAC ducting?

David B. Benson wrote:How about HVAC ducting?

Very much doubt it. Far too substantial (at least an inch thick steel in the background), steel (so far too conductive to be effective) and not 'closed' tubing in any way.

Let's withhold judgement on the piece shown above.

There could have been a semi-tubular entrance to Winter Gardens at this location and this could be part of it's structure. This debris could be a mix of WTC1 and the Winter Gardens entrance.

Enhanced view of the initial moments of the WTC 1 North Face.

As always, I recommend conversion to HuffYuv format and scrub-viewing within VirtualDub.

http://www.youtube.com/watch?v=33Cc7Hdo7Ak

In two new video clips by femr we can see the moments when the upper perimeter sheet separates and falls from the lower sheet along the WTC1 northwest corner and the first 12 columns on the north face without a trace of buckling.

Because of the wind direction these columns are more visible than the others which are obscured by a veil of smoke.

The first clip is a close-up of these columns. Same link as in the last post, relinked below

Please notice:

1) Early outward forceful movement of a column about 10 spaces from the corner. The column is clearly pushed outwards with significant force even before the corner fails.
2) Not the slightest trace of buckling, ripping or any kind of deformation due to resistance to failure during the sheet separation.

The clip http://www.youtube.com/watch?v=33Cc7Hdo7Ak


In the second clip we see the same columns from a wider perspective. We see a small section of perimeter columns remain standing. It is easy to verify the top of this piece is from the 97th floor along the collapse initiation failure line and the columns are the first 6 from the NW corner on the west side of the building. You can see where it comes from via the clip itself.

Please consider these simple questions concerning this rather frail, narrow surviving group while watching:

1) How can the bolt failures along it's edges all break so delicately so as to leave such a frail piece remain suspended in air?

If these bolts were actually ripped by force, why didn't it at least pull the piece down with it?

Consider how much force is required to rip bolt connections relative to how little force is required to knock this frail piece over.

Dearest reader, just reflect a bit and you will come to realize that what you are seeing is physically impossible.

The bolt connections on both sides must, must have been pre-cut or weakened for this unstable piece to be ripped away from the falling structure and still stand.


2) Why is there no trace of buckling or ripping seen on the top of this surviving piece since it's top was supposedly firmly attached to the upper block moments ago?

The clip http://www.youtube.com/watch?v=RN1Fq090sBA&NR=1 The HD version is good.

Major_Tom wrote:1) Early outward forceful movement of a column about 10 spaces from the corner. The column is clearly pushed outwards with significant force even before the corner fails.

The behaviour 'could' be due to separation of the aluminium cladding from the column.

2) Not the slightest trace of buckling, ripping or any kind of deformation due to resistance to failure during the sheet separation.

Whilst I do agree, given we have most of these pieces identified at ground zero without buckling being apparent, it is again possible that the cladding could confuse interpretation.

Linking in images of the relevant sections at ground zero would solidify the viewpoint.

1) How can the bolt failures along it's edges all break so delicately so as to leave such a frail piece remain suspended in air?

The initial rotation of the cap could explain why little vertical force was applied to the remnant, but I agree that it's separation from both North and West face connections is very enlightening. It is clear from video footage that there was very violent ejecta behaviour which traversed specifically down each side of the NW corner. Deliberate separation would seem the most plausible explanation, however I think it would be useful to detail the actual construction of the corner section and its strength relative to a standard facade panel section to determine whether 'natural' behaviour could also be responsible. I imagine the corners were much stronger. I would hope so at least...

This Xenomorph video shows the NW corner ejecta is great detail:
http://www.youtube.com/watch?v=a2yKp39khqI

you will come to realize that what you are seeing is physically impossible.

I suggest a bit of re-wording here. It's not physically impossible, because it occurred. It's the cause that must be clarified. I know what you mean, but I think it's important to be clear.

The bolt connections on both sides must, must have been pre-cut or weakened for this unstable piece to be ripped away from the falling structure and still stand.

I don't think pre-cut is correct, but I do think that each corner was subjected to progressive and deliberate separation. I'll hold judgement a little until I gather details on the physical construction of the corner (which I'm a little grey on at the mo).

Major_Tom wrote:Let's withhold judgement on the piece shown above.

There could have been a semi-tubular entrance to Winter Gardens at this location and this could be part of it's structure. This debris could be a mix of WTC1 and the Winter Gardens entrance.

Let's have another look:

http://femr2.ucoz.com/photo/6-0-183-3 (3072x2048px/1292.4Kb)

It's a compressed version of one of the new Kurt Sonnenfeld images. The original is 3.5Mb, so I had to compress it a little (jpeg 10) to get it under 1500Kb (my image size limit).

It's "sonnenfeld_WTC - 19.jpg" in the Sonnenfeld archive.
http://www.911blogger.com/node/20835
(The torrent is a LOT quicker than the direct download)

MT... I'm afraid download is a MUST for you, and you'll be spending the next couple of weeks identifying all sorts of important photographic features. I suggest we start a new thread for the purpose, if not a separate section.

Greg... Think analysis of a 650Mb photo archive warrants a (sub)section ?

A note for femr:

In the link below I am only interested in the image played over and over again for the first 30 seconds.

http://www.youtube.com/watch?v=dtx_GcFCs6c&feature=channel_page


Speculation: The west face peel is done in sections. It is not a whole wall peel from top to bottom. Height-wise the large single piece seen extends from floor 94 to just below the lower mechanical room.

I believe you guessed somewhere that the west perimeter breaks just under the first mechanical floor also. I think you are right.


I think it may be possible to verify that the single sheet seen falling westward actually pivots at it's base around an axis just below the lower mechanical floor.

Why do I point this out? Because the WTC2 east face peel is identical in that the huge sheet breaks just under the lower mechanical room.

They are identical.


So my previous idea of whole perimeter peeling was a bit off. The single sheet peel only extends down to about floor 36 (?).

Major_Tom wrote:A note for femr:

In the link below I am only interested in the image played over and over again for the first 30 seconds.

http://www.youtube.com/watch?v=dtx_GcFCs6c&feature=channel_page

Another couple of versions you may be interested in:
http://www.youtube.com/watch?v=pC0ZBSDBZCY
http://www.youtube.com/watch?v=samGjZ8nKgk

Speculation: The west face peel is done in sections. It is not a whole wall peel from top to bottom. Height-wise the large single piece seen extends from floor 94 to just below the lower mechanical room.

I agree, though I'm not sure where the separation points actually are, and I'm pretty sure that the large segments were not formed from the full width of each tower. Bits were, others seemed narrower.

I believe you guessed somewhere that the west perimeter breaks just under the first mechanical floor also. I think you are right.

I think that segmentation at both mechanical floors was a more probable behaviour. For me, the structural differences at each mechanical floor region are reason-enough for my, admittedly, speculative viewpoint. For the lower mechanical floor separation, yes, after looking through your diagrams of the peel I watched the videos linked until my eyes went fuzzy and got the impression of the behaviour described (separation at mechanical). The camera viewpoint is pretty static, so it may be practical to consider feature tracking/acceleration graphing/smearograms...I'll see if I can come up with anything useful as soon as I can. (Am multi-tasking )

These column tree did not come from the Twin Towers.
It looks like a column from the core of Building 7.

OK, I solve this mystery.
Its a steel section of the northern West Street pedestrian bridge, which connected the WTC with the WFC complex.



Before the 9/11 Attacks:

MrKoenig wrote:

These column tree did not come from the Twin Towers.
It looks like a column from the core of Building 7.

Why ? The dimensions can be checked of course. What were the dimensions of the section of WTC 7 you think it originated from ? Did WTC 7 have closed box columns ?

And, Welcome

femr2 wrote:

MrKoenig wrote:

These column tree did not come from the Twin Towers.
It looks like a column from the core of Building 7.

Why ? The dimensions can be checked of course. What were the dimensions of the section of WTC 7 you think it originated from ? Did WTC 7 have closed box columns ?

And, Welcome

The same column tree and same steel worker, seen from further away:


Full-size:
http://algoxy.com/psych/images/pre.cut.salvage.box.column.jpg

The I-beams are too long for a horizontal core column-to-core column bracing in the Twin Towers, for my opinion

Unfortunately I can not examine the exact location of this column.
Either its the Barclay Street and in the background the rubble pile of Building 7, or its the corner of Vesey Street and West Street, with the half-demolished WTC6 in the background.
(OK, I can except the Barclay Street, because some exterior panels from the Twins' are visible behind the excavator)

Building 7 had closed box columns at its perimeter.
(But its not the same column, the I-beams or the Wide Flange beams here are too short)

For example:

*comment withdrawn*