Re: 911 After the theory, some facts

Barbara Lake wrote:
Thank you, James,

Since I am one who knows absolutely nothing about the construction of large buildings, Florian's posts were giving me a decidedly queasy feeling. You have ably countered his arguments. Thank you.

Barbara

Barb, your reaction to what Florian said would, in my opinion, be considered normal.

Have you noticed, throughout the many times these past years where we have often mentioned the 9/11 incident, Florian never mentioned that he thought the towers were deliberately destroyed. Such a thought was not introduced to the public until George Clooney, John Kerry, and some others started talking about it. That ought to have alerted you to thinking Florian is just grasping at straws hoping to cause doubts in peoples minds, as is the case with those I previously mentioned. Which would be somewhat easy to do if there was a mindset that was already against Bush. Remember the saying "The enemy of my enemy is my friend". It's just natural that odd fellows would tend to accept ways and means that would unite and support a common cause. The reality is, he doesn't or didn't know how high rise buildings may be constructed. Even in design, mans imagination of a worst scenario may well be exceeded, as it was when the planes crashed into the Towers, with topped tanks of thousands of gallons of fuel.

BTW, if anyone tries to tell you that lower floors in a super high rise are designed to support loads of upper collapsing floors and therefor should not collapse, tell him to take a hike. Because that fellow may be an idiot, there's no reason why you should follow suite and appear to be one too.





"Amused" <Amused@xxxxxxxxxxxxxxxxxx> wrote in message news:vIydnQ9k8vAhTKrZnZ2dnUVZ_sidnZ2d@xxxxxxxxxxxxxxxxxxxx
There was an intensive investigation of why the buildings collapsed. They weren't suppose to.

New York skyscrapers are designed to withstand a airplane crash into the building, ever a B-26 flew into the Empire State Building during World War II.

As it turns out, the Twin Towers withstood the crashes as they were designed to do. It was the tons of jet fuel that were the culprits in the total collapse of the buildings.

The Twin Towers were built using a relatively new construction technique. Instead of the usual rigid steel I-beams going up the outside of the building, the actual rigidity of the building was provided by a central core and then the integrity of the surrounding floors were stabilized by a system of steel stringers. These stringers were approximately two inches in diameter and criss-crossed to provide lateral rigidity and strength. While there were steel beams in the shell of the building, they were not the usual massive beams used in conventional construction, where each floor's beams has to support all the weight of the floors above it.

By using the dynamic tension of stringers, it was possible to build a much lighter building, overall. And cheaper, no doubt. There just wasn't nearly as much concrete and steel in the buildings as one would normally expect.*

*During the Middle Ages, Europeans building some of the soaring cathedrals, discovered that there were limits as to how high they could go, before the stone bases began to crumble under the weight of the stone above. Thus the "flying buttresses" were created. These designs provided stability, while allowing the actually walls to be built lighter. Steel skeleton buildings have a theoretical limit, also. At some point, the steel I-Beams on the lower floors have to be made so massive, to prevent deflection, and support the weight above, that the floors lose a significant and costly amount of their usable space.

The central core was as heavily constructed as any normal building. When the two jets flew into the buildings, both penetrated to the core. And all that jet fuel spilled inside the building, and was ignited. Since the core had been breeched, too, the fire immediately set up an airflow, much like a chimney would. Combustibles, especially paper and fabrics, added fuel to the fire.

The fuel was mostly contained within the buildings and a spread out across the level floors. Inside temperatures quickly increased well beyond the normal ignition temperatures of jet fuel.* Exactly the same process is achieved in blast furnaces to create the steel in the first place.**

*During some of the firestorms over European and Japanese cities in World War II, core temperatures exceeded those of the sun. Steel didn't just melt, it burned. As the fires accelerated, gale force winds developed as the surrounding air was sucked into the maelstrom. In some fringe areas, people in basements and bunkers didn't actually die of the heat, but from a lack of oxygen as the fire consumed all the available gas.

** As a personal note, a few years ago, I had dispose of a rather large amount of scrap wood. Any given piece was relatively small, but there were a lot of pieces. I build a small fire on a (limestone) gravel driveway. It quickly became obvious that it would take two days to feed all the pieces into that small a fire. I, instead, took an electric leaf blower and pointed it directly at the base of the fire. Fuel consumption that would normally have taken several minutes, was reduced to seconds, and there were no cinders left. It was complete consumption. The heat generated was intense. Later, I was unable to find any small nails or staples, except around the edge of the fire. After the fire, the limestone rocks were very crumbly, and some of the sand had actually fused into small bits of glass. There was no ash, only a perfectly round circle of very white rocks.

As the temperatures increased, the steel stringers didn't melt, per sec, but they did soften and the building, on those few floors, directly in the flight path, began to lose their strength, and the tension that was used to keep the everything in it's place, became unbalanced. The relatively weak outside beams kept everything in place for a while, until there was a catastrophic event and all that weight from the upper floors, came crashing straight down. Stringers on lower floors didn't melt, they just snapped, or anchor points failed. The floors pancaked almost straight down.

BTW, concrete walls, subjected to intense heat, begin to crumble, rather quickly. Residual moisture in the concrete, expands, and the concrete begins to flake. Sometimes, these flakes can be ejected almost explosively. It is quite possible, in specific situations to "burn" through a concrete wall.

Concrete is porus, and water will "flow" through a concrete wall. That's why all basements have to have a "waterproofing" coat, usually tar, applied to the outside of the wall.

If you'll notice, the specially fired brick (called fired brick) in your fireplaces probably doesn't have any exposed morter. There's a reason for that.

IF the Twin Towers had been constructed in the usual manner, computer modeling shows that the aircraft would not have penetrated so deeply into the buildings, and a fair amount of the jet fuel wouldn't have been contained inside the buildings. If the Twin Towers didn't have a perfectly designed "chimney" exactly in the center of the building, that allowed the generation of exceeding high temperatures, damage would have still been extensive, but a total collapse would have been unexpected.*

* The central core of the buildings provided the raceway for all utilities, including the fire suppression/sprinklers. It is postulated that the jets probably severed most of sprinkler piping when they breeched the core.

I, personally, would speculate, that since the concrete used was not intended for structural purposes (to provide rigidity) and it was known that it wasn't a thick as usual, the tremendous forces moving straight down, actually pulverized into dust, a much larger percentage that would be expected. In addition, I would guess that the non-structural concrete would contain less rebar and wire.

To continue with this speculation, I do know that demolation crews specifically consider using the smallest explosives possible to achieved controlled implosions, in an effort to create big chunks of concrete. It's much eashier to clean up chunks than it is to clean up small pieces.

Extensive interviews with the chief architect, well after the events, revealed that neither he, nor anyone else, had ever considered the effects of so much jet fuel in a contained space. Post 9-11 computer modeling, using the known circumstances, produced much the same as observed results.

Thus, it was a combination of factors, that created the catastrophe.

James....
This is a summation of a documentary broadcast by the Discovery Channel about 18 months after 9/11. Since it is from memory, it is, of course, subject to the vulgarities of my memory, and should not be considered, in any way, as complete or sacrosanct.

It's simply a advancement of the idea, that when the exact conditions of the events are known, in hindsight, the observed results are not particularily surprising, and no elaborate conspiracies are needed to explain them.

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