29-09-2013, 11:20 PM
(This post was last modified: 30-09-2013, 12:05 AM by Tony Szamboti.)
Jeffrey Orling Wrote:Phil Dragoo Wrote:I find the content is important
yet we are given to understand that 2,300 degrees are required to accomplish this very essential-to-the-propaganda feat
No one has made a claim that 2,300°F was required to weaken the steel in order to facilitate failure. At 900° steel has lost 50% of its' strength... at 1100° it has about 20% of its strength.
Please refer to the chart at this link to see how metal strength related to temperature
http://www.engineeringtoolbox.com/metal-..._1353.html
The chart you show is not very accurate. Attached here is one strictly for structural steel from the AISC (American Institute of Steel Construction). Steel loses about half its strength at 600 degrees C (1,112 degrees F). The AISC document I got this from is available free of charge here http://www.aisc.org/WorkArea/showcontent.aspx?id=7046 See page 9 on the lower left for the chart.
[ATTACH=CONFIG]5338[/ATTACH][ATTACH=CONFIG]5339[/ATTACH]
Click on images to enlarge
The steel columns in the 98th floor core of the North Tower (where the collapse initiated) would have needed to be heated to about 650 degrees C (1,202 degrees F) to even be at the point where they could not handle the load above them and start buckling, and the average resistance of those heated columns during buckling would be too high to allow the sudden, then constant and fairly rapid acceleration of 5.1 m/s^2 it was measured at. See above attached image of this measured data. This actually proves heating was not the cause of the initiation, as heated columns would have started buckling and moving downward slowly and then gathered acceleration. It could not have been constant acceleration, or nearly as rapid, if the buckling started when the heating and the load became just enough to start the process.