WhiteLion
17th June 2007, 02:09 PM
On the white-power forum Stormfront, the belief that 9/11 was an inside job is prevailing it seems.
Here is a post in argument toward the truthers there; (warning, links go to hate-speech listed site)
http://www.stormfront.org/forum/showpost.php?p=4304710&postcount=38
Here's the reply;
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Yes, reinforced concrete can add to the fire resistance of a building. However, given two buildings of equal mass, one purely steel and the other made of reinforced concrete, the steel building will be much stronger. Steel is far stronger in tension, compression, and fatigue. Otherwise battleships would be made of concrete. Concrete is a good, inexpensive method for constructing flooring and walls. Remember that concrete has zero tensile strength, and a compressive strength only around 3500psi. The yield strength of steel is typically ten times that.
My skepticism regarding 911 stems from some models I made of the collapse. I was interested in the effect that conservation of momentum would have on the rate of collapse, especially because the claim has been made that the towers collapsed at free fall speeds. I did both a simple spreadsheet model in Excel, and a more complex model in a 2D physics program (Working Model). Both models showed that conservation of momentum adds a minimum of five seconds to the collapse of a 100 story tower. Therefore it is physically impossible for a progressive collapse to occur at free fall speeds. These were simple models. I made no attempt to model additional factors that could add significantly to the collapse time.
My concern is that even if the NIST collapse model is correct, it fails to explain how the towers collapsed as if there were no internal resistance whatsoever. Or why they collapsed in symmetrical fashion in the direction of greatest structural resistance. The NIST's inability to explain the collapse of WT7 is simply ridiculous. Even if one accepts their disclaimer, it is inexcusable. Monolithic, almost instantaneous collapses of major steel framed structures are unheard of and warrant extended and thorough investigation. The results, including all design information, failure models, simulations, and corrective actions should be readily available for the world community. After all, the job of the NIST is to catalog scientific information for use by the American scientific community. Here's their job description from their web site: http://www.nist.gov/public_affairs/general2.htm
"NIST's mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life."
Really, the only reason for their inability to explain the collapse of WT7 must be ........ their inability.
You mention the Kader building collapses, but it has problems.
1) It took well over half an hour for the first Kader building to progressively collapse, and the subsequent buildings took an additional hour. The WTC buildings collapsed in less than 15 seconds.
2) The Kader collapse was asymmetric whereas the WTC was symmetric.
3) The Kader collapse only affected steel structure with no fireproofing. The WTC buildings had excellent fireproofing.
4) The Kader buildings had an additional problem, lack of compartmentalization, whereas the WTC towers had excellent compartmentalization
5) The Kader buildings didn't even have automatic sprinklers.
6) The Kader buildings were only 4 stories high.
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I haven't studied the Kader collapse that much, however in the post above the truther naturally assumes that WTC7 fell in the path of greatest resistance, which the previous post had just proved it didn't.
Furthermore, I would inquiry as to how the heck he thinks fiddling with Excel and Working Model renders his position more qualified than NIST's report? Heh.
At the beginning of his posts, he also seems to apply a false scenario; "However, given two buildings of equal mass, one purely steel and the other made of reinforced concrete"
This was on the Windsor-WTC7 comparison, where the argument before his post had been that the steel in the Windsor-fire had collapsed as would have the building, hadn't it been for the reinforced concrete.
Now, on this he argues a strange comparison between a steel reinforced concrete building and one "purely steel".
Last time I checked, WTC7 was far from a pure steel building. :confused:
Here is a post in argument toward the truthers there; (warning, links go to hate-speech listed site)
http://www.stormfront.org/forum/showpost.php?p=4304710&postcount=38
Here's the reply;
------------------------------------------------------------------
Yes, reinforced concrete can add to the fire resistance of a building. However, given two buildings of equal mass, one purely steel and the other made of reinforced concrete, the steel building will be much stronger. Steel is far stronger in tension, compression, and fatigue. Otherwise battleships would be made of concrete. Concrete is a good, inexpensive method for constructing flooring and walls. Remember that concrete has zero tensile strength, and a compressive strength only around 3500psi. The yield strength of steel is typically ten times that.
My skepticism regarding 911 stems from some models I made of the collapse. I was interested in the effect that conservation of momentum would have on the rate of collapse, especially because the claim has been made that the towers collapsed at free fall speeds. I did both a simple spreadsheet model in Excel, and a more complex model in a 2D physics program (Working Model). Both models showed that conservation of momentum adds a minimum of five seconds to the collapse of a 100 story tower. Therefore it is physically impossible for a progressive collapse to occur at free fall speeds. These were simple models. I made no attempt to model additional factors that could add significantly to the collapse time.
My concern is that even if the NIST collapse model is correct, it fails to explain how the towers collapsed as if there were no internal resistance whatsoever. Or why they collapsed in symmetrical fashion in the direction of greatest structural resistance. The NIST's inability to explain the collapse of WT7 is simply ridiculous. Even if one accepts their disclaimer, it is inexcusable. Monolithic, almost instantaneous collapses of major steel framed structures are unheard of and warrant extended and thorough investigation. The results, including all design information, failure models, simulations, and corrective actions should be readily available for the world community. After all, the job of the NIST is to catalog scientific information for use by the American scientific community. Here's their job description from their web site: http://www.nist.gov/public_affairs/general2.htm
"NIST's mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life."
Really, the only reason for their inability to explain the collapse of WT7 must be ........ their inability.
You mention the Kader building collapses, but it has problems.
1) It took well over half an hour for the first Kader building to progressively collapse, and the subsequent buildings took an additional hour. The WTC buildings collapsed in less than 15 seconds.
2) The Kader collapse was asymmetric whereas the WTC was symmetric.
3) The Kader collapse only affected steel structure with no fireproofing. The WTC buildings had excellent fireproofing.
4) The Kader buildings had an additional problem, lack of compartmentalization, whereas the WTC towers had excellent compartmentalization
5) The Kader buildings didn't even have automatic sprinklers.
6) The Kader buildings were only 4 stories high.
-----------------------------------------------------------------------
I haven't studied the Kader collapse that much, however in the post above the truther naturally assumes that WTC7 fell in the path of greatest resistance, which the previous post had just proved it didn't.
Furthermore, I would inquiry as to how the heck he thinks fiddling with Excel and Working Model renders his position more qualified than NIST's report? Heh.
At the beginning of his posts, he also seems to apply a false scenario; "However, given two buildings of equal mass, one purely steel and the other made of reinforced concrete"
This was on the Windsor-WTC7 comparison, where the argument before his post had been that the steel in the Windsor-fire had collapsed as would have the building, hadn't it been for the reinforced concrete.
Now, on this he argues a strange comparison between a steel reinforced concrete building and one "purely steel".
Last time I checked, WTC7 was far from a pure steel building. :confused: