In , Swan Radioman wrote:

On Fri, 19 Sep 2003 10:27:10 -0600, "JJ"
wrote:


Miles wrote in message ...


jim wrote:

i said the same thing several days ago and was lambasted by posters
here. the response 'that is flat out false' was directed my way. i saw
the same program as you. it was what made the wtc unique.

Other people said that because your statement is flat out false. What
is unique is the fact the outer structure doesn't provide gravitational
support as is found in most other skyscrapers. The weight is born
almost entirely on the central core. Whatever show you two watched was
either in error (doubtfull) or you misunderstood their description.

http://www.skyscraper.org/tallest/t_wtc.htm

Faced with the difficulties of building to unprecedented heights, the
engineers employed an innovative structural model: a rigid "hollow tube"
of closely spaced steel columns with floor trusses extended across to a
central core. The columns, finished with a silver-colored aluminum
alloy, were 18 3/4" wide and set only 22" apart, making the towers
appear from afar to have no windows at all.


Gee, wonder why when the buildings collasped they fell inward toward the
center followed by the outer walls? Did you notice when the second building
collasped the tv antenna on top fell straight down in the center and that is
were it wound up at the bottem? If this center column was the strength of
the building, then just how did that happen? Did you notice that after the
collaspe that the only things standing were some of the outer walls, no part
of any center column? Whe? Because the center columns were NOT the main
strength of the building, that was in the outer steel structure. That was
pointed out in the documentery by both the Architect and Engineer who
designed the buildings. So this website is either in error or you
misunderstood their description.


The inner core supported the weight of the building, the exterior
columns were designed for wind loading.
The outer wall remained after the collapse because they weren't the
primary support for the building.


The report on the design of the building by the architects reads as
follows:

In order to make each tower capable of withstanding this wind load,
the architects selected a lightweight perimeter tube design consisting
of 244 exterior columns of 36 cm square steel box section on 100 cm
centers (see Figure 3). This permitted windows more than one-half
meter wide. Inside this outer tube there was a 27 m × 40 m core, which
was designed to support the weight of the tower. It also housed the
elevators, the stairwells, and the mechanical risers and utilities.
Web joists 80 cm tall connected the core to the perimeter at each
story. Concrete slabs were poured over these joists to form the
floors. In essence, the building is an egg-crate construction that is
about 95 percent air, explaining why the rubble after the collapse was
only a few stories high.

Maybe you misunderstood what the documentary stated. I also watched
it, and the mention of the outer columns was in reference to wind
loading, not support of the weight of the building.

The floors of the buildings were built from trusses, with one end attached to
the central core and the other end attached to the outer columns. That means the
weight of each structure was supported by BOTH the outer shell AND the inner
core.

Now how about arguing over something a little less morbid, huh?





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