Re: 911 After the theory, some facts
- From: "Barbara Lake" <bglake@xxxxxxxxxxx>
- Date: Sat, 8 Apr 2006 09:50:56 -0700
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.
"Amused" <Amused@xxxxxxxxxxxxxxxxxx> wrote in message
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
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
*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
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
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
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.
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
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