I would like to add that steel is an excellent conductor of heat. It has the annoying property of wicking heat away from it's source, as anyone can tell you who has had to heat and bend large sections of steel. It's very difficult to raise the temperature of the steel without adequate heat.
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How the Towers' Fires Affected the Structural Steel
As an exercise let's set aside all of the evidence about the actual severity of the Twin Towers' fires, and imagine that the fires were incredibly intense and widespread. Let's imagine that the jets were full tankers and spilled 80,000 gallons of fuel into each tower. Let's imagine that there was a strong wind giving the fires plenty of air. Let's imagine that the the fires engulfed over 10 floors in each tower, saturating the capacity of the steel buildings to draw away the heat. Let's imagine the fires burned intensely for hours, completely gutting several stories of each tower. Would that cause them to collapse? Not according to people who have studied steel structures subjected to such stresses. The following passage is from Appendix A of FEMA's World Trade Center Building Performance Study.
In the mid-1990s British Steel and the Building Research Establishment performed a series of six experiments at Cardington to investigate the behavior of steel frame buildings. These experiments were conducted in a simulated, eight-story building. Secondary steel beams were not protected. Despite the temperature of the steel beams reaching 800-900º C (1,500-1,700º F) in three of the tests (well above the traditionally assumed critical temperature of 600º C (1,100º F), no collapse was observed in any of the six experiments).
This graph represents strength as a function of temperature, which is expressed in degrees Celsius (C).
At temperatures above 800º C structural steel loses 90 percent of its strength. 1 Yet even when steel structures are heated to those temperatures, they never disintegrate into piles of rubble, as did the Twin Towers and Building 7. Why couldn't such dramatic reductions in the strength of the steel precipitate such total collapse events?
High-rise buildings are over-engineered to have strength many times greater than would needed to survive the most extreme conditions anticipated. It may take well over a ten-fold reduction in strength to cause a structural failure.
If a steel structure does experience a collapse due to extreme temperatures, the collapse remains localized to the area that experienced the high temperatures.
The kind of low-carbon steel used in buildings and automobiles bends rather than shatters. If part of a structure is compromised by extreme temperatures, it may bend in that region, conceivably causing a large part of the structure to sag or even topple. But it will not crumble into pieces.
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Additional information
Unbiased, independent structural study not related to 9-11
http://911research.wtc7.net/wtc/arch...html#structure
http://911research.wtc7.net/disinfo/...e/trusses.html
Video:
MIT engineer and research scientist Jeff King: what most likely happened (Approx. 8 minutes)
911 - Various Clips (approx 15 minutes
Okay folks... this is the first installment. There is much much much more to come. As you digest this info I'll be working on the next section. I've invested a considerable amount of time and effort into reviewing, searching and pulling all of this together, and I am willing to commit to many more hours to provide accurate and credible information. In addition, I am putting my reputation, my own credibility and any respect I may have earned on this site on the line. This fact is not at all lost on me. SO I would appreciate a modicum of respect in this exercise...
Thanx, Okham