Severe Damage Claims

WTC Building 7

Claims of Severe Damage to Building 7

NIST's preliminary reports on WTC 7's collapse includes a slide presentation named: Project 6: WTC 7 Structural Fire Response and Collapse Analysis. 1 A key tenet of its theory is that the building sustained severe structural damage from heavy pieces of debris cast out by the collapse of the North Tower, whose closest wall was about 400 feet from Building 7's south wall.

Page 14 of the slide presentation makes the following claims about damage from debris from the North Tower.

Debris Damage from WTC 1

After WTC 1 collapsed:

         * Heavy debris on Vesey Street and WTC 7 Promenade
         * No heavy debris observed in lobby area, white dust coating
         * SW Corner Damage -- floors 8 to 18
         * South face damage between two exterior columns - roof level down 5 to 10 floors,
            extent not known
         *South Face Damage
                  o middle 1/4 - 1/3 width south face, 10th floor to ground
                  o large debris hole near center around 14th floor
                  o 1/4 width south face, above 5th floor, atrium glass intact
                  o 8th/9th floor from inside, visible south wall gone with more damage to west,
                     2 elevator cars dislodged into elevator lobby

Page 19 contains this illustration.

This slide, labeled Estimated Extent of Debris Damage indicates that a huge gouge hollowed out Building 7's south face.

The only evidence NIST adduces in support of its "estimated extend of debris damage" are the following two images, which apparently hadn't surfaced until NIST published its presentation. SW Corner Damage
Minor Damage to Parapet Wall Both the image above and the image to the right are contained in NIST's slide presentation entitled: Project 6: WTC 7 Structural Fire Response and Collapse Analysis. They are the only two images provided to support NIST's conclusion that Building 7 sustained severe structural damage from the collapse of the North Tower. The first shows a giant gash in the building's southwest corner extending from the 18th floor downward, and the second shows damage to the parapet wall at the top of the south-facing facade.

The alleged minor damage to the parapet wall appears to be the only evidentiary basis for NIST's claim of a huge gash in the middle of the south facade, since no photographs show this damage.

The alleged southwest corner damage is interesting because there are no known photographs that show this corner of the building from the 18th story down. In fact, it is the only corner of the building whose 8- to 18th-floor span is not shown by other public photographs.

In the following three video captures, smoke obscures the portion of WTC 7's southwest corner below about the 18th floor.


These frames extracted from the video WTC: The First 24 Hours show Building 7 on the afternoon of 9/11/01

Damage Claims Versus Symmetric Collapse

Even if one accepts all of NIST's claims about extensive structural damage to WTC 7, and its claims about fires on several different floors, its collapse scenario is not remotely plausible. The alleged damage was asymmetric, confined to the tower's south side, and any weakening of the steelwork from fire exposure would also be asymmetric. Thus, even if the damage were sufficient to cause the whole building to collapse, it would have fallen over asymmetrically -- toward the south. But WTC 7 fell straight down, into its footprint.

References

1. WTC 7 Structural Fire Response and Collapse Analysis, NIST.gov,