"Keith W" wrote in
:
"Wake Up!" wrote in message
...
"Wake Up!" wrote in news:Xns978626A6D8B0Atruth@
130.81.64.196:
Whatever, though, for you to simply assume that WTC 7, a steel framed
building, totally collapsed near free fall speed from fire, you are
definitely not qualified. A qualified engineer would know that steel
framed buildings do not completely collapse from fire. Never. Sorry.
A qualified engineer knows that steel framed buildings can and
do collapse from fire. Indeed the building codes require fire
protection material to be applied to structural members to prevent
such a collapse.
I have in my collection photos of 2 large buildings gutted by fire
during the London Blitz of 1940, one was steel framed the
other was built using beams of Baltic oak. The steel framed
building collapsed, the oak framed building had its timbers
charred to a depth of 1" but stayed upright
Were those complete collapses? Regardless, we are talking about modern
steel framed skyscrapers. Not those from 60 years ago. Sorry.
Moreover trusses such as those used in the WTC buildings are
notoriously prone to such failures, there's an a excellent article
on the risk associated with trusses at
http://www.cdc.gov/niosh/docs/2005-132/
Interesting how that government info was written *after* 9/11
Fire protection cannot ensure that buildings stand indefinitely.
They are designed to ensure adequate time to evacuate the
building which is what happened in WTC 7
Okay.
Of course if the fire is preceded by an impact that pre-weakens
the structure and blocks the stairwells from above the impact
point complete evacuation will not be possible and the building
will collapse early.
Okay.
ALL the qualified engineers who have reviewed the evidence
know what caused the WTC collapse and it wasnt thermite
or explosives, it was fire and impact damage. The evidence
of truss failure is incontrivertable and the subsequant failure
mechanism of buckling is clearly evidenced on the video.
They came to that conclusion because the NIST report "does not actually
include the structural behavior of the tower after the conditions for
collapse initiation were reached".
According to Dr Jones, the evidence for controlled demolitions comes
after collapse initiation.
The lessons of the WTC collapse is that such truss construction
techniques should be avoided for high rise buildings, fortunately
they are not widely used which is why previous high rise
fires didnt lead to progressive collapse.
Keith
----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet
News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the
World! 120,000+ Newsgroups ----= East and West-Coast Server Farms -
Total Privacy via Encryption =----
There's an interesting thread he
http://forum.physorg.com/index.php?s...a913744121c597
&showtopic=3108
many different opinions.
Also, this paper from a Mechanical Engineering Professor:
http://www.911blogger.com/2006/03/me...ssor-from.html