WTC2 E Face Perimeter Pulls in, Breaks Along Bolt Seam
High resolution video shows that the line of perimeter columns along the east face of WTC2 which bent inwards during the earliest moments of collapse initiation broke along bolt connections after being pulled in.
There is no evidence that the perimeter buckled inwards. There is substantial evidence that the east perimeter broke into an upper and lower sheet cleanly along a zig-zag line of bolt connections with no permanent column deformation or buckling. The action of the break is shown:
We extract the most informative frame images from frames 11650 to 11760 of the high resolution version of the WTC2 compilation video here. This corresponds to the 4 second interval, 6:29 to 6:33 in the video. The high resolution download is here
These images show:
1) Increased inward bending until frame 11070
2) The visible columns become straight again after that point. This means that the tension that caused the columns to bend has disappeared. The upper columns have broken, or "snapped" from the lower visible columns.
3) The visible columns were never bent past their elastic limit before "snapping" from the upper columns. The bending caused little permanent deformation and the columns quickly straightened up again when the cause of tension was removed.
Part 2 of this presentation, using other portions of the same video compilation linked earlier, will show
4) When this lower sheet of columns fell away from the building a few moments later, it's entire upper edge was clearly visible from multiple angles, showing that the break between upper and lower happened completely along bolt lines in a zig-zag pattern over 3 floors.
All columns along the top edge appeared very straight as they fell from the building. There was no evidence of a single buckled columns along the top edge of the falling sheet.
All images are in chronological order.
Frame 11653
frame 11659
frame 11665
frame 11671
frame 11679
frame 11690
frame 11695
frame 11702
In the image above the bending reaches a maximum inward displacement.
In the following images we see the visible columns quickly straighten.
There is no longer the evidence of increased inward bending. Instead, there is a release of tension as the visible columns break away from their connections above.
Please observe as the visible columns return to their former (straight) shape.
frame 11707
frame 11716
The image below shows the columns once again quite straight.
As they return to their former shapes and positions we see an open space, a empty hole is left where the upper columns once were.
frame 11736
frame 11741
In the last image in our short but educational presentation we see the camera has zoomed out allowing us to see how the upper sheet of columns has folded into the building and inside the lower straight visible columns.
Notice the obvious difference in angle between the upper and lower right corners of the building. The upper part is folding within the lower part.
frame 11756
Part 2 of this presentation will identify the line along which the east perimeter "snapped" into upper and lower. I will show that it was a clean, unbuckled break completely along bolt lines.
The two images below, of the top edge of the lower sheet moving outwards, show a small taste of what the type of break I mean. The first image shows how clean and unbuckled the break was, while the second image hints that the pattern stretched across the entire east face, from the NE to the SE corners of the building.
The upper edge of the sheet is marked in the graphics:
It is the first stepped pattern of bolted connections above the 75-77 Stiff MER panels.
The orange line marks a row of welded and bolted conections. They prove much stringer than the connections along the stepped pattern shown.
Photo archive of debris in the area east of WTC 2 here
1) The spandrels along the blue lines pull inward and downward. The upper large standard sheet is pulled behind the red sheet, breaking along the upper edge of the large MER stiffening plate (green belt). The upper edge is marked in purple.
2) The red middle sheet falls outward, breaking at the base just above the 41-43 MER panels and fall down over 40 fls to earth leaving the purple lower sheet standing. It also breaks along the upper edge of the 41-43 MER stiffenig belt (purple line).
3) The lower sheet then falls outward and was found lying practically interconnected from the base of the footprint to the 44th fl.
4) The stiff NE corner breaks along the 3 red marks. No info on SE corner breaks.
5) The top of the tower pinched inward just under the hat truss and top MER stiffener as it was leaning (as shown).
UPPER SECTION
The upper sheet falls completely behind the middle sheet:
There is evidence that the east facade of WTC 2 from the 80th floor downwards fell as an interconnected single sheet of unbuckled perimeter column sections. The spandrel plate connections and column-to-column bolt connections remained largely intact until far into its fall.
Here is a glimpse of the sheet falling away from the building:
which fits the pattern of the lowest bolted connections shown above with the addition of 2 more panels shown in red:
Note the middle sheet falling away from the building. the upper MER level (fl 43) is morked in red.
The middle3 sheet will emerge from the building dust moments later as seen in the video below.
The middle perimeter from fls 78 to 44 is seen emerging from the bottom of the bulging dust in this video:
LOWER SECTION
Wide MER spandrels for fls 41-43 north half marked in red. Wide MER spanrels for south half marked in green.
This is the debris as it looked just after 9-11-01. The large MER sections sit at the very end of what appears to be a large, rolled-out sheet of perimeter wall. It is, in fact, the entire east side of WTC2 from the 41-43 fl MER level downward., about 60 columns wide (57 to be exact, excluding the cornermost sections).
A view from the side. The MER panels marked in green are along the bottom of the photograph.
Blue lines mark the wide spandrels from the lowest MER level above ground level. The red and blue boxes mark where the right and left halves of the 41-43 MER perimeter were found.
Other wide MER spandrels are marked.
Clean-up operations have already cleared debris in the lower left corner of the photo but the size of the intact east side of the building is obvious.
Even from the debris we can see that the spandrels split along the NE and SE corners of the building yet remained relatively intact between the corners.
Note the identical break line relative to the wide MER spandrels that was seen above the 75-77 MER failure line.
There is only one unique place it can fit in the graphic: It is the entire right half of the perimeter wall. The broken spandrels on the right must be one perimeter panel (3 columns) in from the northeast corner of the building.
The piece next to a street sign:
And where is the intersection of Church and Cortlandt? In the red oval below.
We can see the entire east face of WTC2 below floor 81 "peeled" away from the building, falling over WTC4, its top edge (the mechanical room sheets) landing along Church Street.
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