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Progressive Collapse Resistance of Steel Building Floors

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posted on Dec, 7 2007 @ 10:38 AM
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I haven't read the entire study from Berkley but happened upon this and thought I'd share for discussion.


This one test only established the potential of typical steel structures to resist progressive collapse in the event of sudden removal of a column.


www.ce.berkeley.edu...

Let me know what ya'll think.

Especially considering that one column is suppossed to be the straw in the back of the camel called WTC 7.




posted on Dec, 7 2007 @ 10:40 AM
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reply to post by Griff
 



BTW, the study was done pre-9/11.

Also what I find interesting is the bibliography.



posted on Dec, 7 2007 @ 12:38 PM
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Wow, I open it up, and what is the very first name I see?

"Abolhassan Astaneh-Asl." This is the guy who was on the FEMA BPAT team at Ground Zero and later went before Congress saying the team wasn't allowed enough evidence to look over, no structural documentation, etc.

So August 2001 (a MONTH before 9/11) and we have the future lead-investigator for the FEMA BPAT team already involved with an investigation into the "progressive collapses" of steel floors of a building, something that had never happened before (but supposedly happened the very next month, two or three times in a row, even). Damn. That's interesting enough to have warranted opening the document by itself.


From their conclusions:


1. The ultimate capacity of the structure following a loss of column is limited by the beam-to-column connections at the lost column. The catenary action of the beams and steel deck appear to be adequate to prevent progressive collapse provided that connection bolts do not prematurely fail.


Applied to the WTC this doesn't mean much to me except that the perimeter columns could have been vulnerable to bolt failure as soon as they began buckling at the connections, but I already figured this. Most perimeter columns failed at the bolts just like that anyway. They didn't even need explosives to sever them.

The core columns, though, and the entire core structure, was welded together. All of the core columns were fully welded end-to-end, smoothed out afterwards and everything.


Going on:


2. The steel deck is effective in redistributing the increased load resulting from the loss of a column. Maximum stress readings during the tests were mostly between 5 and 15 ksi, however, localized small areas of deck yielded. Failure of the steel deck through ripping or tearing was isolated and did not limit the strength of the system.

3. The combined Catenary action of floor steel deck and the simply-supported girders was able to prevent collapse of column with a load of about 63 kips in the column. This load corresponds to about 300 kips per square feet of tributary area of the floor. Considering a reduction factor of 0.5 due to impact, the floor load that was carried by Catenary action could be established as about 150 pound per square feet of tributary area.

4. This one test only established the potential of typical steel structures to resist progressive collapse in the event of sudden removal of a column. Further research is needed to establish the parameters that affect this resistance and to develop appropriate design guidelines to take advantage of this phenomenon in preventing collapse of structures.



Well, what they were able to actually show does no help whatsoever to the "official story," whatever that is (NIST never analyzed global collapse, yet rebutted FEMA's pancake theory
).



Flagged and starred. Anyone interesting in the "collapses" of the Twin Towers and WTC7 needs to look at this.

[edit on 7-12-2007 by bsbray11]



posted on Dec, 7 2007 @ 03:10 PM
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here's something similiar that's new.

buildings fall down



posted on Dec, 7 2007 @ 04:01 PM
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Originally posted by billybob
here's something similiar that's new.

buildings fall down


Thanks for posting that. Did you notice the ads by google at the bottom?


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BsBray,

Nice catch about the researching engineer. I missed that.





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