The "Truss Theory"
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 800ºC 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.
|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.
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 800°C 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.
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...
...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.
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.
Watch the video. No structure falls from WTC 1.
The Collapse of WTC 1: Madrid Exposes a Fundamental Flaw
The 9/11 WTC Collapses: An Audio-Video Analysis
What Really Happened