The "Truss Theory" - A Fantasy Concocted to Conceal a Demolition

"...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)

According to [WTC designer Leslie Robertson], New York City has some of the worst wind loads in the nation ... This is because of the occasional wind generated off of the Atlantic Ocean during hurricane season. As a result, buildings in New York City must be designed to be twice as strong as similar buildings designed to withstand an earthquake in Los Angeles. [NYC24]

"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."

Aircraft Comparisons:
Boeing 707 - Boeing 767

Video of DeMartini's comments

If the above is true then why is it claimed the twin towers were bolted together with non-composite (weak) steel deck trusses? There would be no strength in the structure.

To illustrate the point lets take a close look at two fundamental parts of the official 'truss theory', namely the trusses and bolts...

The WTC trusses (shown above) spanned 60' and 35' between the inner core and perimeter walls.

Here is a floor plan showing the layout of trusses used in the twin towers construction:

A small piece of the plan has been highlighted in red. This is where a truss is attached to the inner core. Details of the inner core:

The core was designed to support the entire weight of the buildings several times over. Far more than a mere "service core", it comprised of 47 steel box columns tied together at each floor by steel plates, similar to the 52" deep spandrel plates that tied the perimeter columns together. The largest of these core columns were 18"x36", with steel walls 4" thick near the base and tapering in thickness toward the top, and was anchored directly to the bedrock.

Photograph showing WTC 1 inner core during construction:

The inner core of WTC 1 was the most solid part of the building.

According to the WTC Report the only thing securing trusses to the inner core and perimeter walls were 5/8" bolts:

A chain is only as strong as it's weakest link, and these permanently stressed bolts would be a very weak link - they'd had 30 years of wear and corrosion - but if the 'truss theory' is to be believed then they were the only things holding the twin towers together.

On 9/11 Flight 11 plowed into WTC 1 at 470 mph, the inner core of the building bore the brunt of the 150+ ton airliner's impact.

wmv video of impact 831kB

'Truss theory' trusses failing

If the 'truss theory' were true then the force of the plane's impact would have knocked the inner core backwards, this would have crushed numerous trusses on the opposite side of the building and sheared off a massive number of truss connecting bolts.

Airliner & debris weight + bolt failures + catastrophic truss failures = immediate "pancake collapse" of all floors (but not the core).

History shows this didn't happen.

Cary Sheih on the 72nd floor of WTC 1 when Flight 11 hit the building:

'I heard a loud explosion, which was immediately followed by tremendous building sways and vibrations. As I was thrown out of my chair, I immediately thought that this was an earthquake, but still thinking rationally, I thought that it was abnormal since there are no earthquakes in NYC, especially of this magnitude. I remember thinking that the building felt like it was going to collapse from this initial explosion.' [TruthOrFiction]

WTC 1 shook and swayed so violently that it threw Cary Sheih from his chair, but it remained standing. This is incredible, especially when you consider the following collapse study:

Weak single bolts 'contributed to WTC collapse'

The single-bolt connections in the framework of the World Trade Center popped and fell apart during the September 11 terrorist attacks, causing the floors to collapse on top of each other, according to a new study. The analysis, conducted by a team of researchers from the Massachusetts Institute of Technology (MIT), concludes the bolts did not properly secure the towers' steel floor trusses, The New York Post reported yesterday. [CBS News]

If the building was truly held together by weak bolts then the single bolt connections should have "popped and fell apart" when Flight 11 smashed into the inner core of WTC 1, not 1˝ hours after the event.

The only way WTC 1 could have survived Flight 11's impact is if the building was solidly constructed.

At the heart of the structure was a vertical steel and concrete core, housing lift shafts and stairwells.

Steel beams radiate outwards and connect with steel uprights, forming the building's outer wall.

All the steel was covered in concrete to guarantee firefighters a minimum period of one or two hours in which they could operate - although aviation fuel would have driven the fire to higher-than-normal temperatures.

[BBC News 9/13/2001]

Below are 2 zoomed images of this WTC construction site photograph. They show steel beams connecting the south tower's outer walls to it's inner core, not trusses:

Below is an image from Modern Marvels: World Trade Center showing the inside of a WTC building:

Bridging trusses (highlighted) add considerable strength to the structure.

The buildings were indeed solidly constructed, proof of this lies in the fact they stood for thirty years in winds which sometimes reached hurricane force. Would Ľ mile high buildings which relied solely on the integrity of weak trusses and 5/8" bolts have stood for thirty years?

When Flight 11 flew into WTC 1, one of two things should have happened:

If the building was constructed with non-composite steel trusses bolted between the inner core and perimeter walls there should have been an immediate "pancake collapse" of all floors (but the core should have remained intact).
If the building was solidly constructed it should have remained standing.

Neither of the above occurred.

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

Update:

In 2006 NIST revised the "truss theory" because it did not withstand scrutiny.

The following video shows the revised theory.

NIST is now stating sagging trusses pulled the outer columns inwards until they spontaneously failed. This may occur in parameter deficient computer models, but in the real world the 5/8" truss connection bolts would fail long before the outer columns.

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 1000°C (1832°F). ... 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 implausible, especially when you consider the lack of fire in the towers.