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"...this is the result of something that was planned. It's not accidental that the first tower just happened to collapse, and the second tower just happened to collapse in exactly the same way."

WMV video download (248kB)

The "Truss Theory"
is Implausible

The perimeter walls of the twin towers were made up of lightweight sections connected by bolts and welds. [details]

The graphic on the left shows the failure of trusses connecting the perimeter walls to the inner core as dictated by the "truss theory".

Note that as trusses fail the perimeter walls lose support.

The perimeter walls would have had little strength without the bracing of trusses, therefore mass truss failures would have resulted in large sections falling off. If the graphic were factual then Flight 175's impact [video] should have gouged a large hole in the side of the building as masses of trusses would have been obliterated as the plane travelled through the building.

Also, The Windsor Building in Madrid was of similar design to the twin towers, and the video on the right showing the 2005 fire in the building shows large pieces of structure falling off because trusses were failing in the 800C fires on the upper floors of the building.

The Windsor Building fire shows that debris should have rained down from the twin towers as trusses failed, especially toward the time of the collapses, and there should have been gaping holes in the buildings' perimeter walls when the buildings came down.

Right-click link, 'Save Target As' to download video
Fire cascading from the Windsor building - 334kB wmv video

This wasn't the case.

The animated gif and video on the right show only minimal aircraft damage in the side of WTC 2 immediately before its collapse, and this indicates the building's internal structure was intact. This is confirmed by firefighters transmissions from the impact area.

The Windsor Building fire demonstrates the structural failures in WTC 2 should have been slow, chaotic and visually progressive, instead they were instantaneous, uniform and visually explosive.

High Resolution DivX video of above collapse (1.6MB)

"And while I was still in that immediate area, the south tower, 2 World Trade Center, there was what appeared to be at first an explosion. It appeared at the very top, simultaneously from all four sides, materials shot out horizontally. And then there seemed to be a momentary delay before you could see the beginning of the collapse." [Frank Cruthers, Chief (F.D.N.Y.)]

Video showing collapse

This is not the signature a building collapsing through failing trusses.

Another part of the collapse also defies the proposed "truss theory".

The image below is a highly enlarged screenshot of the MPEG version of the above video. Unfortunately it is not too clear - it is only a guide as to what to look for in the high resolution video.

Point A marks structural damage in the corner of WTC 2 in which 800C fires supposedly burned.

Point B marks a solid piece of structure well above the aircraft impact level.

The "truss theory" dictates that fire destroyed the building's structural integrity in and around the level of point A at the time of the collapse.

The theory is the heat of the fire softened not only the floor trusses but also the walls of the outer skeleton they were attached to. When the steel was sufficiently weakened by the heat the walls and the trusses would have pulled apart and without the trusses to hold them rigid the columns of the outer walls started to bend and then fail. [BBC Horizon]

When the collapse starts the building above the level of point A should plow through the building below because of mass truss failures.

Watch the videos.

When the top of the structural damage at point A hits the bottom of the structural damage the building's structure breaks in the area of point B, but the corner of the perimeter wall below point A doesn't even buckle when the weight of 25+ floors falls onto it.

If weak trusses and weak bolts were the only things connecting the perimeter walls to the internal core...

WTC truss

...then the building below the impact area should have visibly disintegrated at the start of the collapse, but it didn't. WTC 2 was held together by something a lot more substantial than trusses and bolts.

"The building was designed to have a fully loaded 707 crash into it, that was the largest plane at the time. I believe that the building could probably sustain multiple impacts of jet liners because this structure is like the mosquito netting on your screen door - this intense grid - and the plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting."

Video of DeMartini's comments

Also note WTC 1 in the high resolution video. It had burned for longer than its twin, so if the "truss theory" is believed then this building should contain more failed trusses than WTC 2, therefore the seismic shockwave generated by the collapsing adjacent building should dislodge numerous pieces of structure from the impact area of the building.

Cary Sheih -WTC 1 Survivor:

"I was a few floors from the ground. Floor,,,,4,,,,then all of a sudden, a loud boom, and the building began to shake unbearably again. People started falling down the stairwell as smoke started to rise from the bottom. The emergency lights flickered and then went out. The building was still shaking, and I could hear the steel buckling." [TruthOrFiction]

Watch the video. No structure falls from WTC 1.

So what happens when World Trade Center type trusses are heated?

Well,... from the evidence, the answer is: Not that much happens. The photo below shows a number of trusses and a buckled steel column after the June 1990 Broadgate Phase 8 fire. Consider the following piece from here (section 1.1) concerning the fire.

"On the 23rd June 1990 a fire developed in the partly completed fourteen storey building in the Broadgate development. The fire began in a large contractors hut on the first floor and smoke spread undetected throughout the building. The fire detection and sprinkler system were not yet operational out of working hours.

The fire lasted 4.5 hours including 2 hours where the fire exceeded 1000C (1832F). ... The structure of the building was a steel frame with composite steel deck concrete floors and was only partially (fire) protected at this stage of construction. During and after the fire, despite large deflections in the elements exposed to fire, the structure behaved well and there was no collapse of any of the columns, beams or floors."

[Full details]

The "truss theory" is a fantasy concocted to conceal a demolition.

See also:

The Collapse of WTC 1: Madrid Exposes a Fundamental Flaw
The 9/11 WTC Collapses: An Audio-Video Analysis

What Really Happened

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