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The studies by Bazant et al, that demonstrate that unlimited creep (i.e., to catastrophic failure) is a function of BOTH temperature & stress level have been presented numerous times. And those studies have shown that, at high stress levels, runaway creep can occur at temperatures as low as 150°C.
Anyone who ignores those studies and continues to say that "steel will remain unaffected by heat up to 500°C" is incompetent.
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There's no experiment performed here. There is an experiment described. Not performed.
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No video shows any "steel exploding". Absolute nonsense.
Video shows connections rupturing, steel being thrown outward, gypsum being turned into particulates, concrete being crushed and lots of debris being tossed outward.
Tom
Suggest you study the NIST report
Fire Protection of Structural Steel in High-Rise Buildings. at
http://www.bfrl.nist.gov/pdf/GCR04_872.pdf .
Note that NIST confirms that the WTC destruction was a singular event that has never happened before or after 911 2001, and, not spelled out, has not been explained! That creep would produce a one-way crush down of a structure is not confirmed anywhere.
Actually, the whole purpose of fire protection of structural steel in high-rise buildings is just to delay the occurence of local failures allowing people to get out and fire fighters to get in. That local failures due fire in turn can produce a one-way crush down or progressive collapse of any kind of a complete structure, most of it unaffected by the fire, is simply not possible - as explained in post #1 of the original thread.
The 911 videos show quite clearly how the complete steel/composite structures explode in a fountain of debris. Sorry - no
'progressive collapse' (sic) of any kind.
It seems that this
'progressive collapse' of steel structures buisiness started long after 911 with strange models where some mass elements are assumed rigid (sic!) and that these rigid mass elements are held in position by springs and non-rigid connections. In even stranger simulations, the connections of a rigid mass element are assumed to fail so that the rigid mass element drops and contacts another rigid mass element, the connections of which fail, and .... HOKUS POKUS ... we have a progressive collapse!
Actually, all these models and theories simply confirm that progressive collapse is only possible with rigid mass elements (or complete rigid assemblies of rigid mass elements). As no such elements or assemblies of elements exist in the real world, progressive collapse or, even worse, one-way collapse of a structure by a part of itself (topic) is simply not possible.