9 - 1 1 R e s e a r c h

an attempt to uncover the truth about September 11th 2001
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NOTE: See this more recent version of this article.


The truss theory is the absurd belief that the only support (between the central core and the perimeter wall of the World Trade Center) for the concrete floor slabs, was lightweight trusses. It was invented to explain away what were obviously demolitions and has become the "official" dogma. The central core, perimeter wall and the mythical trusses are all introduced in the article: The World Trade Center Demolition. There you will find out their dimensions, their numbers and their supposed usage. The following illustration describes one of the mythical trusses.

It is from: Chapter Two of the FEMA Report into the WTC collapse.

According to the "official" story, there is no significant lateral support for the walls (against wind loading) between the ground and top floors. This is like a bridge with a 1,300 foot span between supports. Even though the tube structure of the perimeter wall was designed for maximum rigidity (within the given weight specifications) the 1,300 foot span between supporting pillars, meant that even this very rigid design would sag in the midsection under wind loading, just like a bridge with such a span. In a typical steel framed building the span between pillars is only 12 feet (one floor) and such a problem does not arise.

The World Trade Center towers were like huge sails in the wind. These sails had to be able to resist the 140 mile per hour winds of a hurricane. Such hurricane force winds exerted a large (some 6000 tons) lateral force on the building. This lateral force is called the wind loading (or force of the wind) on the building. According to the "official" story, the only possible intermediate support comes from the flimsy trusses and the lightweight concrete floors. The WTC was designed to survive a 45 pounds per square foot, wind loading. This translates to a 12 x 207 x 45/2000 = 56 ton force on each of the floor segments. What this 56 ton force on each floor segment means, is that if one was to lay the World Trade Center on its side and use the pull of gravity as a substitute for the push of the wind, then each of the 110 floors would need to be loaded with a 56 ton block of steel (so the entire wall would have to support 110 such blocks of steel, that is, 110 x 56 = 6160 tons in total).

The fact that the tubular structure of the walls is very rigid, does not stop the central core from needing to bend when the walls bend. This means that the walls have to transmit the full force of the wind to the core, so that the core will flex to the same extent as the walls (this is obvious, otherwise if the walls flex while the core does not, the floor slabs would, by definition, be crushed). Again, it is important to note that the rigidity of the walls does not protect the central core from the full force of the wind, what it does, is it limits the distance that the walls (and hence the whole structure) can bend. The more rigid the design the less it tilts in the wind.

In strong winds the midsection of the windward wall will be pushed several feet towards the core. In a typical steel framed building of WTC type design, heavy steel beams transmit the wind loading to the core, which then bends together with the walls. However, in the WTC (as described in the "truss theory") the trusses and floor slabs are too weak to transmit this force to the core without buckling, so the core will stay in its original position as the wall advances to it. This will crush the trusses and floor slabs, leading to the collapse of many floors. Since this did not occur during the 30 years in which the buildings stood, we must assume that the "official" story is false. To see how utterly ridiculous the "official" story is, lets calculate the lateral loading (wind loading) that each one of these trusses was expected to resist. Consider, a one floor segment. Here, we have 30 trusses and a slab of concrete supporting 56 tons. That is about 2 tons per truss and piece of slab. If you balanced a 2 ton block of steel on top of one of these flimsy 60 foot long trusses and (a 60 foot long by 6 foot 8 inches wide by 4 inches thick) slab of concrete, we all know what would happen - the truss and slab would buckle and collapse.

Another point to consider, is that if the walls alone handle lateral loading, then the pressure on the windward wall must be transmitted via the corners to the remaining walls (this transmission of loading to the other walls is what gave the WTC its rigidity) but the corners are far too weak to handle this task alone.

Although the "truss theory" is ludicrous, it has been pushed by many "experts". It should be noted that it is inconceivable that these experts did not know that it was false.


This picture is of early construction of the south tower.

The central core and perimeter wall have been marked in red (the inner rectangle bounds the central core and the outer rectangle bounds the perimeter wall). "Trusses" visible at the top level have been marked in white, those visible one floor down have been marked in magenta. At this point the perimeter box columns are spaced at ten foot intervals. Higher up the structure, these perimeter box columns will split into three smaller columns (each roughly 14 x 14 inches), spaced 40 inches apart. Knowing this we can measure that the depth of the so-called "trusses". We find that they are approximately 18 inches deep.

So what do you see with your own eyes? Trusses or solid steel girders?

The original photo from which the above picture was taken can be found here. In case you are wondering, the path like structure that passes through the building is a subway line.

Below, is a floor plan showing the positioning of the supposed (double) trusses. It is from the FEMA report.

So what do you see with your own eyes? One sees what appear to be solid steel girders laid out according to the plan for the positioning of the trusses. Have another look. What you see are certainly not trusses.

Below, we present another photo showing what appear to be solid steel girders (once again laid out according to the plan for the positioning of the supposed trusses).

To make things clearer, the position of the "trusses" have been marked in white. The vertical red lines correspond to visible core columns and the white lines (apart from the outer perimeter lines) correspond to visible floor joists (you know, the supposed trusses). Remember, that the perimeter columns which appear like a row of toothpicks in the visible sections of the wall, are actually 14 inches wide. Thus the floor joists (the supposed trusses) do indeed appear to be quite large steel beams. One thing is certain though, they are not the claimed trusses.

The original photo from which the above enlargement was made can be found here. If one looks at the very top of the North Tower, one can also see evidence of steel beams occurring where there should only be trusses.

The following is another photo showing what appear to be solid steel girders where there should only be trusses.

Here we have another photo of early construction work on the South Tower. Behind, is the North Tower and further back, the Verizon building. The photo was taken from the old extention of Greenwich Street (which was ripped up to make way for WTCs 4 and 5) looking north west. Some interesting aspects of the construction are presented in the following enlargements of the red-boxed regions.

In this enlargement one can see eight perimeter box columns on the left. At this height, they are spaced at ten foot intervals. Of course, what is of interest here are the eight (seven on the lower level and one on the upper) quite solid looking beams spanning the 35 foot gap between the perimeter wall and the central core, where the "official lie" promises us there are only flimsy trusses.

In the foreground of this enlargement one can see eighteen perimeter box columns of the South Tower (those in the background are of the North Tower). If you look closely, you can just make out a single quite large beam spanning the 60 foot gap between the central core and the perimeter wall. Remember, that the corner core column to which this beam is attached is some 3 foot wide (and 16 inches deep).

Note that one or two floors below this, workers are working on a section of flooring held up by what might be trussing. This appears to be temporary flooring. It should be noted that it is clear that trussing was used during the construction to provide temporary flooring, but equally clearly, it was not used to provide the main support for the concrete floor slabs.

In these two photos the steel beams (supposed trusses) mentioned above, are marked in white.

So what do you see with your own eyes? One sees what appear to be solid steel girders laid out according to the plan for the positioning of the trusses. Have another look. What you see are certainly not trusses.


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