Originally posted by bsbray11
There was a role of concrete in the construction of the Windsor Building that was not present in the WTC, or, as far as I know, the Caracas Tower, and thus I refrain from referring to the Windsor Building.

And again, no evidence of either severe fires of critically heated steel. No glowing, no tested samples showing above 250 C, etc. That is, until after the collapse.

Many conspiracy theorists point to FEMA's preliminary report, which said there was relatively light damage to WTC 7 prior to its collapse. With the benefit of more time and resources, NIST researchers now support the working hypothesis that WTC 7 was far more compromised by falling debris than the FEMA report indicated. "The most important thing we found was that there was, in fact, physical damage to the south face of building 7," NIST's Sunder tells PM. "On about a third of the face to the center and to the bottom--approximately 10 stories--about 25 percent of the depth of the building was scooped out." NIST also discovered previously undocumented damage to WTC 7's upper stories and its southwest corner.

NIST investigators believe a combination of intense fire and severe structural damage contributed to the collapse, though assigning the exact proportion requires more research. But NIST's analysis suggests the fall of WTC 7 was an example of "progressive collapse," a process in which the failure of parts of a structure ultimately creates strains that cause the entire building to come down. Videos of the fall of WTC 7 show cracks, or "kinks," in the building's facade just before the two penthouses disappeared into the structure, one after the other. The entire building fell in on itself, with the slumping east side of the structure pulling down the west side in a diagonal collapse.

According to NIST, there was one primary reason for the building's failure: In an unusual design, the columns near the visible kinks were carrying exceptionally large loads, roughly 2000 sq. ft. of floor area for each floor. "What our preliminary analysis has shown is that if you take out just one column on one of the lower floors," Sunder notes, "it could cause a vertical progression of collapse so that the entire section comes down."

There are two other possible contributing factors still under investigation: First, trusses on the fifth and seventh floors were designed to transfer loads from one set of columns to another. With columns on the south face apparently damaged, high stresses would likely have been communicated to columns on the building's other faces, thereby exceeding their load-bearing capacities.

Second, a fifth-floor fire burned for up to 7 hours. "There was no firefighting in WTC 7," Sunder says. Investigators believe the fire was fed by tanks of diesel fuel that many tenants used to run emergency generators. Most tanks throughout the building were fairly small, but a generator on the fifth floor was connected to a large tank in the basement via a pressurized line. Says Sunder: "Our current working hypothesis is that this pressurized line was supplying fuel [to the fire] for a long period of time."

WTC 7 might have withstood the physical damage it received, or the fire that burned for hours, but those combined factors--along with the building's unusual construction--were enough to set off the chain-reaction collapse.

Originally posted by FEMA

No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire.

In light of the above statement is it fair to ask? . . .
1) Has any steel-frame building, before or after the WTC buildings, ever had a jet airliner fly into it?
2) Has any steel-frame building, before or after the WTC buildings, ever been hit with such lateral force?
3) Has any steel-frame building, before or after the WTC buildings, ever sustained itself after the resulting impact of a jet airliner, explosion and burning of 11,000 gallons of fuel?
4) Has any steel-frame building, before or after the WTC buildings, ever sustained itself after the resulting impact of a jet airliner, explosion and burning of 23,500 gallons of fuel?

No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire.

In light of the answers to the 4 questions, is the above statement fair?

The building was subjected to a three year refurbishment programme of works when the fire broke out. The major works included the installations of:

* Fire protection to the perimeter steel columns using a boarding system
* Fire protection to the internal steel beams using a spray protection
* A sprinkler system
* A new aluminium cladding system

The refurbishment was carried out floor-by-floor from the lower floors upwards. By the time the fire broke out, the fire protection for all steelwork below the 17th floor had been completed except a proportion of the 9th and 15th floors.

Originally posted by Killtown
Yes it's fair. An larger airliner hit a large steel building in Holland and the building only partially collapsed:

Originally posted by bsbray11
Put into context the amount of damage done before the fires supposedly brought the towers down.

There was less than 15% total column damage in either tower in all likelihood. I say "in all likelihood" because no one went in to examine the core columns, but any common sense would dictate that after the initial impact into the steel perimeter columns, the planes' remains weren't going to have much strength to face the much thicker and wider-spread core columns, of which there were nearly 50 in either building. But the numbers for the perimeter columns were about 11% and 13% severed in the impacted region.

Now, according to NIST's own information regarding the safety ratings of the core and perimeter columns, the buildings would have to have an average of a 75% total column failure on any given floor to cause a whole floor to collapse.

The impacts caused about 15% column failure, so the fires would have to cause over 60% column failure.

Look to ANY steel skyscraper fire, in the history of the world, and show me where any such fire has caused 60% column failure on any given floor!

Originally posted by jinsanity
If you look at the second plane crashing into the building the majority of it's fuel blew up outside the building.

Originally posted by bsbray11
The same source also provides that on and above the 17th floor, fireproofing on the steel was not yet commenced (with the exception of the 18th floor being partially completed). That means no fireproofing at all above the 17th floor for the whole 18 to 20 hours for the fire, which maxed around 800 degrees Celsius.

Observations of paint cracking due to thermal expansion. Of the more than 170 areas examined on 16 perimeter column panels, only three columns had evidence that the steel reached temperatures above 250 ºC: east face, floor 98, inner web; east face, floor 92, inner web; and north face, floor 98, floor truss connector. Only two core column specimens had sufficient paint remaining to make such an analysis, and their temperatures did not reach 250 ºC. ... Using metallographic analysis, NIST determined that there was no evidence that any of the samples had reached temperatures above 600 ºC. (p 90/140)

Using metallographic analysis, NIST determined that there was no evidence that any of the samples had reached temperatures above 600 ºC.

You are neglecting the role of the floor slabs in providing lateral stability to the columns.

Did the floor slabs fail?

Yes. From the initial impact and from the subsequent fires.