Proofs of Demolition

Demolition of the Twin Towers is Provable Through Simple Analysis
Despite the destruction of the most significant evidence of the Twin Tower collapses -- the structural steel -- it is relatively easy to prove the towers were demolished. Determining how they were demolished without the benefit of the steel may be difficult or impossible, but proving that a gravity-driven collapse is insufficient to explain the characteristics of the collapses documented by photographic and seismic evidence is not.
There are numerous pieces of evidence that strongly indicate demolition, including the fact that authorities destroyed and suppressed evidence, the more than 100 years of engineering experience with steel-frame buildings, the misleading representation of the towers' design by truss theory proponents and the implausible sequence of events proposed by that theory, and the many collapse features that seem irreconcilable with gravity-driven collapses.
Proving demolition requires more than enumerating evidence. It requires making logical inferences about events using the evidence. Three fairly strong proofs are as follows. These are presented as qualitative arguments only. Each suggests an approach for developing a rigorous quantitative proof.

* The towers fell faster than they could have if they were crushing themselves.
* The volume of dust was too great to have been the product of a gravity-driven collapse.
* The South Tower's top shattered before falling, and so its breakup was not a result of gravity-driven crushing.

Speed of Fall
Twin Towers' Rates of Fall Proves Demolition
The towers collapsed completely in intervals of time similar to that taken for a block of wood dropped from a tower's roof to reach the ground. A block of wood has about the same average density as the main components of the towers near their tops.
In a vacuum, a block of wood (or lead) would take 9.2 seconds to fall from the tower's roof. In the air a block of wood, say ten inches on a side, might take 50 percent longer than in a vacuum. Fifteen seconds, a good estimate for the total time of collapse of the North Tower, is about the time it would take our block to fall from the roof. The rubble from the Tower probably had similar average density to our block of wood, since the floor slabs consisted of corrugated sheet metal and lightweight concrete, and the perimeter steel columns were hollow with walls only 1/4th inch thick at the Towers' tops. Air resistance alone could account for the slowing of the falls to the point where each Tower took about 15 seconds to completely come down.
The official story requires that more than air resistance was slowing the descents. The falling rubble would be having to crush every story below the crash zone -- ripping apart the steel grids of the outer walls and obliterating the steel lattice of the core structure. The resistance of the intact building itself would be thousands of times greater than air resistance.
If air resistance is able to increase total collapse times by even 20 percent, then shouldn't the addition of the resistance of the buildings themselves increase the time several thousand percent, to at least tens of minutes?
Of course the idea of a collapse lasting minutes is absurd. So is the idea of a steel frame building crushing itself.

Breakup of WTC 2's Top
Shattering of South Tower's Top Proves Demolition
There are several pieces of evidence that show the structure of the 30 stories of the South Tower above the impact zone was shattered before it started its precipitous plunge. How could the steel frame of many stories above the impact zone have broken up even before it started to fall? The proponents of gravity-driven collapse maintain that the tops of the towers crushed the floors below the impact zones as they fell. The tops functioned as pistons, according to Bazant and Zhou, crushing the stories one by one. What one actually sees in the case of the South Tower is that their piston disintegrated even before it started to fall. A gravity-driven collapse cannot account for that disintegration, nor for how a cloud of rubble could crush the intact structure below the impact zone.


These frames from a South Tower collapse video are separated by equal time intervals. Examining the middle edge of the falling portion of the tower shows that its angle of tilt from vertical remains about the same between the second and third frames, and therefore the top has stopped rotating. But unless the top had already been shattered, it should have continued to rotate in accordance with the law of conservation of angular momentum.

The Mysterious Leveling of Building WTC-7

large high resolution photograph

FEMA on Building 7
Despite the inescapable logic, the official theory for the collapse, as published in Chapter 5 of the FEMA report goes as follows:

* At 9:59 AM (after the South Tower collapse), electrical power to the substations in WTC 7 was shut off.
* Due to a design flaw, generators in WTC 7 started up by themselves.
* Debris from the collapsing North Tower breached a fuel oil pipe in a room in the north side of the building. (This means the debris had to travel across WTC 6 and Vesey Street -- a distance of at least 355 feet -- penetrate the outer wall of WTC 6, and smash through about 50 feet of the building, including a concrete masonry wall.)
* This, and other debris (that also made the journey across Building 6 and Vesey Street), managed to start numerous fires in the building. (Unfortunately, this event did not prompt anyone to turn off the generators.)
* The backup mechanism (that should have shut off the fuel oil pumps when a breach occurred) failed to work, and the fuel oil (diesel) was pumped from the tanks on the ground floor to the fifth floor where it ignited. The pumps emptied the tanks of all 12,000 gallons of fuel.
* The extant fires raised the temperature of the spilled fuel oil to the 140 degrees F required for it to ignite.
* The sprinkler system malfunctioned and failed to extinguish the fire.
* The burning diesel fuel heated trusses to the point where they lost most of their strength, precipitating a total collapse of Building 7.

The last point is the greatest stretch, since it asks us to believe that an event that would be expected only to cause the sagging of a floor instead led not only to total collapse, but to such a tidy collapse that directly adjacent buildings were scarcely even damaged. This is surprising behavior for a steel frame skyscraper designed to survive fires, hurricanes, and earthquakes.
After laying out this highly improbable scenario, the FEMA report authors conclude:
The specifics of the fires in WTC 7 and how they caused the building to collapse remain unknown at this time. Although the total diesel fuel on the premises contained massive potential energy, the best hypothesis has only a low probability of occurrence. Further research, investigation, and analyses are needed to resolve this issue.
Unfortunately for investigators hoping to resolve this issue, nearly all of the evidence had already been destroyed by the time the FEMA report was published.

But... we have some near better; Analysis of Energy Requirements for the Expansion of the Dust Cloud Following the Collapse of 1 World Trade Center (the North Tower)


Documents Destroyed
At the time of its destruction, Building 7 housed documents relating to numerous SEC investigations. The files for approximately three to four thousand cases were destroyed, according to the Los Angeles Times. Among the destroyed documents were ones that may have demonstrated the relationship between Citigroup and the WorldCom bankruptcy.

Collapsing Buildings

The New Phenomenon of Steel Buildings Crushing Themselves
The seven World Trade Center buildings were in the two blue regions of the map here above. On September 11th 2001, all 7 buildings were destroyed. 110-story WTC 1 and 2, and 47-story WTC 7 were leveled, and WTC 3, 4, 5, and 6 were severely damaged, with large portions of WTC 3, 4, and 6 being crushed.
It is interesting that, in spite of the thorough devastation of all the buildings with World Trade Center addresses, no large buildings outside the blue zones were sufficiently damaged to warrant their demolition in the months that followed the attack. 1 The "collapse" of Building 7 was remarkably tidy. Although it was wedged between the Verizon building and the U.S. Post Office building, it barely damaged either of them.
It is even more interesting that, prior to September 11th, no steel framed building had ever undergone total collapse due to any cause or combination of causes other than controlled demolition and severe earthquakes. Such buildings have survived hurricanes, severe fires, earthquakes, and bombings, but none have fallen down of their own weight -- an event that was portrayed as inevitable on September 11th.
Of the collapses of the three huge buildings on September 11th, the collapse of Building 7 is treated separately. If you believe the official story, then Building 7 would be the only example in history of a steel framed building undergoing complete collapse as a result of fires. It and the Twin Towers would be the only permanent vertical steel structures to have fallen into themselves instead of falling over, except in cases of demolition.
The collapses of the Twin Towers are analyzed in much more detail than Building 7 because there is more evidence, and because, whereas Building 7's fall looked like a standard building demolition, the disintegrations of the Twin Towers had many features that are not easily explained.

This image, showing the site of WTC 7, is a small portion of a large high-resolution photograph taken by an airplane flying at 3,300 feet on September 23, 2001. It appears that much of the building's remains have already been removed.

Here a picture of buildings partially collapsed by the 1999 earthquake in Taiwan.