clare at snyder.on.ca wrote:

Exactly what happened , but the weakest point (also initially the
strongest, and the most vulnerable in that building design, was the
core, or elevator shaft. It just happenned the plane penetrated far
enough that the fire and physical damage weakened the core enough to
bring the stry above down. The impact of the center of the next floor
up falling collapsed the next floor of the "core" and it just came
down, top to bottom, like an accordian.

A demolition expert would have brought it down from the
bottom.(generally)
The engineer responsible for the design explained in painful detail
the structural "deficiency" that allowed this to happen. A totally
unforseen, and almost unforseable chain of events that played directly
into the particular structural quirks of the design.

(reduced to just metalworking to aviod the loons -
and it's kinda sorta on topic here)

No argument with anything you wrote here, clare.

Just a reminder that if it isn't in the design requirements, it's not
really a "deficiency".

I don't think it's possible to build an economically viable commercial
building that size that can survive a jet attack of that kind.


YMMV

Richard

On Nov 2, 3:43 am, cavelamb himself wrote:
clare at snyder.on.ca wrote:
Exactly what happened , but the weakest point (also initially the
strongest, and the most vulnerable in that building design, was the
core, or elevator shaft. It just happenned the plane penetrated far
enough that the fire and physical damage weakened the core enough to
bring the stry above down. The impact of the center of the next floor
up falling collapsed the next floor of the "core" and it just came
down, top to bottom, like an accordian.

A demolition expert would have brought it down from the
bottom.(generally)
The engineer responsible for the design explained in painful detail
the structural "deficiency" that allowed this to happen. A totally
unforseen, and almost unforseable chain of events that played directly
into the particular structural quirks of the design.

(reduced to just metalworking to aviod the loons -
and it's kinda sorta on topic here)

No argument with anything you wrote here, clare.

Just a reminder that if it isn't in the design requirements, it's not
really a "deficiency".

I don't think it's possible to build an economically viable commercial
building that size that can survive a jet attack of that kind.

YMMV

Richard
I think it was designed to survive a 727 with a partial fuel (lost in
the fog after a long trip?) rather than a not-yet-designed larger
plane with nearly the full takeoff load.
Also, Robert Moses was powerful enough to bulldoze his pet project
through despite theoretical engineering objections. If you want to
unearth REAL conspiracies, dig into NYC Dem politics, beginning with
Tammany Hall.

Has to do with volume and speed of air ... the same as bellows that were
used in blacksmithing.

Years ago a neighbors house burned down and the metal beams actually melted
.... not twisted but melted..
That was from just wood and air

On Fri, 02 Nov 2007 15:35:54 GMT, "cncfixxer1"
wrote:

Has to do with volume and speed of air ... the same as bellows that were
used in blacksmithing.

Years ago a neighbors house burned down and the metal beams actually melted
... not twisted but melted..
That was from just wood and air

Firefighter friends say they would much rather go into a burning
building with a wood framed roof than a metal frame.
Wood chars from the outside in, and you can see when it is getting
weak. Steel loses it's strength all at one when it reaches a given
temperature, and it turns into a nasty pot of spagetti all at once.


--
Posted via a free Usenet account from http://www.teranews.com

After a Computer crash and the demise of civilization, it was learned
"cncfixxer1" wrote on Fri, 02 Nov 2007 15:35:54
GMT in rec.crafts.metalworking :
Has to do with volume and speed of air ... the same as bellows that were
used in blacksmithing.

Years ago a neighbors house burned down and the metal beams actually melted
... not twisted but melted..
That was from just wood and air

Stainless steel grills are suppose to stand up to bbq fires. They
do, but not when the fire is augmented with coal and a forced draft.
--
pyotr filipivich
"Quemadmoeum gladuis neminem occidit, occidentis telum est. "
Lucius Annaeus Seneca, circa 45 AD
(A sword is never a killer, it is a tool in the killer's hands.)

In article ,
pyotr filipivich wrote:

After a Computer crash and the demise of civilization, it was learned
"cncfixxer1" wrote on Fri, 02 Nov 2007 15:35:54
GMT in rec.crafts.metalworking :
Has to do with volume and speed of air ... the same as bellows that were
used in blacksmithing.

Years ago a neighbors house burned down and the metal beams actually melted
... not twisted but melted..
That was from just wood and air

Stainless steel grills are suppose to stand up to bbq fires. They
do, but not when the fire is augmented with coal and a forced draft.

It needn't even require forced draft. Some African blacksmiths use
charcoal fired forges made of tile pipe hanging from a tree limb or
another handy support.

The pipe has a grate and is open bottom to top with a hole in the side
for the smith to insert workpieces.

Just the natural draft from the heated air up the pipe drawing in cool
air at the bottom can keep the forge hot enough to burn/melt steel.

Way I figure it, the natural draft from the fires in the two main WTC
buildings was probably more than enough to generate enough heat to
weaken the floor trusses. When one gave way, everything above that
slammed into those floors and all of that pancaked into the lower floors.

No conspiracy needed, just lots of fuel and natural draft from the
chimney effect of a tall building with big holes in its sides.

On Nov 2, 8:28 pm, John Husvar wrote:
In article ,
pyotr filipivich wrote:

After a Computer crash and the demise of civilization, it was learned
"cncfixxer1" wrote on Fri, 02 Nov 2007 15:35:54
GMT in rec.crafts.metalworking :
Has to do with volume and speed of air ... the same as bellows that were
used in blacksmithing.

Years ago a neighbors house burned down and the metal beams actually melted
... not twisted but melted..
That was from just wood and air

Stainless steel grills are suppose to stand up to bbq fires. They
do, but not when the fire is augmented with coal and a forced draft.

It needn't even require forced draft. Some African blacksmiths use
charcoal fired forges made of tile pipe hanging from a tree limb or
another handy support.

The pipe has a grate and is open bottom to top with a hole in the side
for the smith to insert workpieces.

Just the natural draft from the heated air up the pipe drawing in cool
air at the bottom can keep the forge hot enough to burn/melt steel.

Way I figure it, the natural draft from the fires in the two main WTC
buildings was probably more than enough to generate enough heat to
weaken the floor trusses. When one gave way, everything above that
slammed into those floors and all of that pancaked into the lower floors.

No conspiracy needed, just lots of fuel and natural draft from the
chimney effect of a tall building with big holes in its sides.

Sorry, but there's not the slightest chance that fire contributed
meaningfully to the collapse of WTC2, because:

1) There was little or no jet fuel in the building.

2) The carpets and furniture were fire resistant.

3) Even if there was an adequate supply of readily combustible fuel
present, 56 minutes is not enough time to develop a fire intense
enough or large enough in extent to weaken the steel enough, given the
thermal mass of steel and concrete present (every floor had hundreds
of thousands of kg of steel and over one million kg of concrete).

On Fri, 02 Nov 2007 02:43:48 -0500, cavelamb himself
wrote:

clare at snyder.on.ca wrote:

Exactly what happened , but the weakest point (also initially the
strongest, and the most vulnerable in that building design, was the
core, or elevator shaft. It just happenned the plane penetrated far
enough that the fire and physical damage weakened the core enough to
bring the stry above down. The impact of the center of the next floor
up falling collapsed the next floor of the "core" and it just came
down, top to bottom, like an accordian.

A demolition expert would have brought it down from the
bottom.(generally)
The engineer responsible for the design explained in painful detail
the structural "deficiency" that allowed this to happen. A totally
unforseen, and almost unforseable chain of events that played directly
into the particular structural quirks of the design.





(reduced to just metalworking to aviod the loons -
and it's kinda sorta on topic here)

No argument with anything you wrote here, clare.

Just a reminder that if it isn't in the design requirements, it's not
really a "deficiency".


That's why "deficiency" is in quotes.

I don't think it's possible to build an economically viable commercial
building that size that can survive a jet attack of that kind.


YMMV

Richard


--
Posted via a free Usenet account from http://www.teranews.com