by Qutb » Fri Nov 11, 2005 7:38 pm
<!--EZCODE QUOTE START--><blockquote><strong><em>Quote:</em></strong><hr>If Qutb doesn't think that WTC7 was CD, then he has no credibility with me.<hr></blockquote><!--EZCODE QUOTE END--><br>I'm waiting for the NIST report on WTC7, and I'll make up my mind after having read it.<br><br>Would it be possible to produce the collapse of WTC7, the way it happend, by planting explosive charges on key columns? Perhaps. Probably. Unlike the towers, you don't get that many clues just by looking at the videos and the pictures. But the gradual collapse of the east penthouse, beginning 8.2 seconds before the main structure begins to collapse, is one clue that may point at structural damage and fire as the cause. At least it shows the columns didn't fail simultaneously. This is also indicated by the "kink".<br><br>I think the following is a bit too much of a coincidence: <br><br>- The penthouse roofline is aligned with interior columns 79, 80, 81. Thus, it is assumed that those are the first to fail.<br><br>- The fifth floor had a pressurized fuel line supplying emergency generators, supplied by two 6,000 gallon tanks.<br><br>- There were no external windows on the third through sixth floors, so it's hard to say how severe the fire was there, but fires were reported on floors 6, 7, and 8.<br><br>- In 1997, fireproofing was observed to be "prominently missing" on fifth floor framing.<br><br>- A transfer system using cantilever girders and trusses between the 5th and 7th floor transferred the load from the upper floors to the structural members and foundation system that was built prior to the WTC 7 office tower. Trusses, with some of the fireproofing missing, are vulnerable in a fire (as seen in the twin towers).<br><br>This is how I undestand the sequence of things in NIST's working hypothesis: An initial failure in the lower floors on the east side of the building and/or a failure of columns 79, 80, and 81 on the east side, led to a failure of floor-column connections progressing vertically up to the penthouse (explaining the collapse of the penthouse), which would pile debris on the east side of the building, which would damage or sever the transfer girders and trusses on floors 5-7, causing a horizontal progression of failure in the core columns (which were supported by the trusses and girders). I have no idea how probable or not this is, but the delay between the collapse of the east penthouse and the rest of the building, and the "kink", would tend to support something like this hypothesis, I think.<br><br>Intuitively, I tend to think that the unusual design with the transfer system on floors 5-7 is the key to the collapse. But I'm of course talking out of my ass regarding that.<br><br>This is what FEMA wrote about it:<br><!--EZCODE QUOTE START--><blockquote><strong><em>Quote:</em></strong><hr>The loss of the east penthouse on the videotape suggests that the collapse event was initiated by the loss of structural integrity in one of the transfer systems. Loss of structural integrity was likely a result of weakening caused by fires on the 5th to 7th floors. The specifics of the fires in WTC 7 and how they caused the building to collapse remain unknown at this time. Although the total diesel fuel on the premises contained massive potential energy, the best hypothesis has only a low probability of occurrence. Further research, investigation, and analyses are needed to resolve this issue.<hr></blockquote><!--EZCODE QUOTE END--><br><br>Further research, investigation and analysis is being done, so let's wait and see what conclusion NIST reach. <br><br><br>-------------<br><br>Mr. Jones said - <br><!--EZCODE QUOTE START--><blockquote><strong><em>Quote:</em></strong><hr>No steel-frame building, before or after the WTC buildings, has ever collapsed due to fire<hr></blockquote><!--EZCODE QUOTE END--><br>The WTC towers weren't conventional steel-framed buildings. If they had been, then quite correctly, they wouldn't have collapsed, at least not the way they did. But if you were to build them in the old-fashioned way, you'd have to use a lot more steel, and it would be difficult to build them that tall.<br><br>No other "tube withing a tube" type building has ever had to endure the amount of damage and fire that brought down the twin towers. <p></p><i></i>