WTC 7's compartmented demolition collapse sequence reveals human intervention.
Demolitions are as good as always planned and executed in compartments (parts).
WTC 2 and 1 were, demo-camouflaged, top-down demolitions.
WTC 7 was a classical, but demo-camouflaged, 45 floors demolition, a so-called bottom-up demolition.
Use this link for constructional details of WTC 7 and to visualize the rest of my post :
FEMA's WTC 7 publication with critic's notes in red.
Pay especially attention to the comments in red!
Most of my following remarks are visualized via drawings and info from within that web page.
The following is a description of how they, without going too much in details, probably executed the demolition sequence.
Since we had no copies of their demo-planning sent to us by the planners, this is a reasonable and viable sequence, based on what online info and
videos we saw, and basic physics:
DEMOLITION SEQUENCE :
1. Cut all the main columns as low as possible, just above or between floors 5 to 7.
This could have been done during the whole day, one by one, as shown on a seismogram with 3 other "further collapses" after the second, North Tower
collapse, which could have been seismic evidence of the cutting of those three columns originating from and starting to extend upwards from above
those huge trusses 1,2 and 3.
That seismogram was published in a November-911 LDEO seismic study of 911 :
Seismic evidence of 3 early WTC 7 explosions, not of further collapses.
Specifically, first at one level, floor 7, near the top of these load bearing transfer trusses and girders-constructions, (huge trusses 1,2 and 3)
which bottom beams stood at floor 5, just over the CON-EDISON floors and the lobby, those three huge trusses were situated between floors 5 and 7.
And secondly at a much higher level, about 7 to 10 floors higher.
Figure 5-5. 3-D diagram showing relation of trusses and transfer girders.
Those 4 floors,
14 to 17, were vacant
on 911 :
Table 5.1. WTC 7 Tenants
Figure 5-6. WTC 7, seventh floor plan, showing locations of transfer trusses and girders.
46-47 Mechanical floors
28-45 Salomon Smith Barney (SSB)
26-27 Standard Chartered Bank
25 Inland Revenue Service (IRS)
25 Department of Defense (DOD)
25 Central Intelligence Agency (CIA)
24 Inland Revenue Service (IRS)
23 Office of Emergency Management (OEM)
22 Federal Home Loan Bank of New York
21 First State Management Group
19-21 ITT Hartford Insurance Group
19 National Association of Insurance Commissioners (NAIC)
18 Equal Opportunity Commission (EEOC)
13 Provident Financial Management
11-13 Securities and Exchange Commission
9-10 US Secret Service
7-8 American Express Bank International
7 OEM generators and day tank
6 Switchgear, storage
5 Switchgear, generators, transformers
4 Upper level of 3rd floor, switchgear
3 Lobby, SSB Conference Center, rentable space, manage
2 Open to first floor lobby, transformer vault upper level, upper level switchgear
1 Lobby, loading docks, existing Con Ed transformer vaults, fuel storage, lower level switchgear
And Hess and Jennings were blown up the stairs, situated directly northeast of the east elevator bank.
Both were blown back up from the sixth to the seventh WTC 7 floor landing again, already before the first, Tower 2, collapsed, that's before 09:59:04
A.M. Thus, note that both towers still stood firm.
And they could not go down, since that stairwell was blown out, with no stairs left.
That's why they climbed up one more floor, to the 8th floor where they went to the outermost northeast corner, where Jennings broke the 8th floor
corner window, and Hess shouted for help to people on the street under the north facade side.
The stairwell they were in and walking down is the orange colored one, at the right side of the elevator banks.
Figure 5-2 Plan view of typical floor framing for the 8th through 45th floors.
Guess which columns were cut that early...The ones under the eastern penthouse, those 2 columns on top of those huge trusses 1 and 2, which collapsed
first at 05:20 P.M. and which event toppled the east penthouse under the main roof line.
Figure 5-7. Truss 1 detail. (BPM = built-up plate member.)
The 5th to 7th floors contained these huge diaphragm floors, belt trusses, and transfer girders where all the mechanical equipment was situated. Nice
calm, and covertly accessible floors...
Figure 5-8. Truss 2 detail. (BPM = built-up plate member.)
These now cut main columns at the 7th floor will still kept standing erect since they were cut horizontally.
Purpose of this first sequence was to cut the main columns, not displace them.
They still stand firm on the non-cut column parts under them.
Figure 5-9. Truss 3 detail.
By the way, cutter charges which are exploding, are downright disappointing in noise level expected by laymen, it's more like a "crack" than the loud
"BOOM" most people expect. Especially in a non-prepared building with all internal structures still intact, and all windows intact.
However, they have an intense seismic effect, since they are so tightly coupled to the columns reaching into the bedrock. See the pack of biggest
spikes in front of the global collapse in the LDEO Palisades station seismogram from 911.
2. Blow out several trusses as high as possible.
(See Figure 5-2)
To insure that all sides of the building will a few seconds later, sag towards the center of the building.
That was the sinking of the eastern and then the western penthouse into the main roof area at 17:20:33 P.M. (FEMA time)
3. Displace some mid-high columns diagonally, by cutter charges, 8.3 seconds later.
You could see the explosive puffs spitting out of the windows on the top floors, sidewards from high up at the western side, and then there were all
the breaking windows at the line of the vertical facade kink, forming on the northern facade. The global collapse now started, and progressed for
about 1 second as a fairly normal gravitational collapse, because the whole underlaying building, as to be expected, resisted the then naturally
proceeding part of the collapse. The graph of that first second is fairly horizontal, showing a slow onset of gravitational acceleration. That's a
sign that constructional failure was not so evident during that first second.
4. Then blow all the already pre-cut parts of the main columns, those 7 to 10 floor-high parts from step 1, with long stretched, directional
Which will displace these cut pieces so far aside, that all the 7 floor high, chunks of main columns, are starting to fall all at once, and there you
have the resulting period of 2.25 seconds of free fall acceleration, of the part of the building above the displaced main columns.
Since now the total 38 to 35 floors part of the building above the 7th floor will undergo no resistance of importance at all, and fall for about 2
seconds in close to free fall over the trajectory of the now zero weight load-bearing 7 to 10 floors, as was demonstrated by David Chandler in his
famous videos, which caused NIST to admit, after publishing their Final Report, that a 2.25 seconds period of true free-fall acceleration existed
during its 16+ seconds total collapse, which occurred during its 16+ minus 8.3 = 7,7+ seconds global collapse, and started about 1 second after global
collapse initiated. There was an 8.3 seconds hiatus between the first sinking of the eastern penthouse into the roof line, and the start of the global
collapse. The total collapse had a slightly more than 16 seconds duration.
Look into all of David Chandler's posted videos and read the comments sections too.
He was the physics teacher who proved to NIST the existence of that so important 2.25 seconds of free fall acceleration. Which they later admitted to
And for those who understand physics, these 2.25 seconds combined with the overall smooth descend of all the building's visible facades, proved
without any doubt possible, that a demolition took place.
This can only happen when all internal resistance has been removed by human intervention.
We first saw 1 second of fairly naturally looking gravitational collapse, caused by blasting a few trusses at top floors.
Then we saw 2.25 seconds of unnatural, free fall gravitational acceleration collapse, where the whole upper floors block fell down 7 to 10 floors,
because all the resisting main columns were blown sideways.
Of course, after the collapsing 30-33 floors top portion fell down, with no resistance of importance because all the 7 to 10 floors in between were
demolished; that whole immense block suddenly impacted the still intact 7 to 10 lowest floors still standing, and then after that event, again a
natural looking gravitational collapse of the whole building proceeded, until all debris settled on the soil.
The lowest 7 floors were hit and demolished by the full weight of the impacting upper block and a deceleration shock-wave rising up the upper block
demolished the rest of the impacting and proceeding downwards, upper block.
A clearly compartmental demolition sequence.
With the intention to hide for the eyes of the world and all the video cameras, as much of the visible explosions and audible effects as they could.
That's why no efforts were undertaken or ordered to fight the fires, which were neglected in the early morning, and why so soon already a no-go area
was ordered and declared, that blocked all efforts of camera men and the public, to get an unrestricted view of WTC 7's lower floors facades.
They only made a mistake by underestimating the seismic effects which showed clearly that whole day's sequences as they proceeded in time.
The cutting of the main columns in the late morning; and after that the firing of those displacement charges beside those 7-10 floors long pieces of
main columns, and then the onset and development of the 2.25 seconds non-natural collapse part. And as the last event, the 7.7+ seconds end phase of
the global collapse.
See for that, LDEO's WTC 7 collapse seismogram, with my remarks added.
I simply connected the time at the place of origin with the time at the place of collection.
And proved human intervention :
Click this FULL 890x766 pixels diagram link.
Click CTRL and + to zoom in.
edit on 17/9/2010 by Mirthful Me because: Mod Edit: BBCode.