posted on Jan, 2 2009 @ 12:06 AM
Well, I shouldn't even comment on this subject. So much has been said on every possible side of the issue. I doubt that there are any open minds left
to persuade.
I am constantly amazed at how little people know about the construction techniques used on the WTC. They continue to repeat the Rosie O rant about
fire temps, steel frames, etc.
The WTC was not a steel frame construction. It was a concrete frame with pre-stressed cables at 3000 psi. It was the first time that buildings over 50
stories to use this constuction technique.
Why did they use this type of construction? Steel frame constuction was too expensive for a massive complex like the WTC. Also, the internal volume of
the buildings would be greater than with the steel frame.
This type of construction has a basic weakness and that is, if enough of the cables in a single column fail, then the entire column fails. If enough
columns fail, then the entire structure fails as the remaining columns are overstressed and the cables within them also fail.
When the cables fail and the 3000 psi of potential energy is released, the column blows itself apart along its entire length, looking like it was
exploded.
This is why so many people are fooled into thinking that a controlled explosion brought down the towers.
What could cause the cables to fail? Well several of the columns in each building were destroyed by the impact of the jets. The building can withstand
the loss of a few columns. However, the remaining columns must now bear extra weight.
As the fuel from the jets burned, it started to cook the columns. As the columns heated up, the strength of the cables within the columns changed. If
you don't know, metals are weaker the closer they get to their melting point. At 3000 degrees, the jet fuel heated the columns enough to cause the
cables to fail.
After 45 minutes of cooking, the cables within the columns started to fail causing further stress on the remaining columns. As a cable fails, the
remaining cables must bear more stress, until the column fails.
As more and more columns fail, the remaining columns are having more and more stress placed on them. Until finally all the remaining columns failed at
the same time, because the weights that they were forced to bear exceeded their maximum strength.
So, that explains WTC 1 and 2. What about WTC 7?
WTC was subjected to huge stesses. The impact of the planes into the WTC measured .7 and .9 on the richter scale. Then the collapse of those towers
measured 2.1 and 2.3.
Debris from the towers fell on WTC 7, that can be seen in the videos. Then there was the huge blizzards of debris from the remains of the towers.
Don't forget that WTC 7 was at the center of those blizzards. All of this happening in short succession over stressed the cables within the columns
of the building.
Those of you who do not work with metal cables may not know this, but once you overstess the cable, the damage is done. The cable is weakened and may
not fail immediately but may fail minutes, hours, days, or weeks later. Don't forget that these cables are tensioned to 3000 psi, that is a huge
amount of potential energy.
One other thing that I have not seen anywhere else is this fact. The WTC was a giant tuning fork. Once struck by the planes, they would have vibrated
at around 550 KHz. This type of vibration would do immense damage to both the towers and the surrounding buildings. The frequency was too high to hear
but based on the force of impact the sound must have been in the hundreds of decibels. Each of the cables within the columns, and the columns
themselves would have resonated with this frequency.
Just like the wine glass that shatters when exposed to its resonant frequency, the columns would have eventually failed. This is simple physics.