lenbrazil
Saturn
Now there's a man with an open mind - you can feel the breeze from here!
Posts: 1,045
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Post by lenbrazil on Jan 3, 2009 14:22:39 GMT -4
“Truthers” make numerous claims which inevitably fall apart under minimal scrutiny. Either that are wrong or their factoid doesn’t prove what they think it does. However a physics teacher seems to be correct that NIST significantly over estimated it took for the first 18 floors of building 7 to collapse. Did I miss where went wrong? I agree with him that even if they saw some slight movement the timing should begin when the roofline actually starts coming down. He did however over play the significance of this. The core obvious collapsed before the north façade because the mechanical penthouses ‘sunk’ and I think the south façade preceded the north one because the building fell south. There is a video shot from the northeast that shows the building tilting south but don’t remember where I saw it. If anyone has the url please post in this thread. The page linked below had 3 still but not the clip. www.debunking911.com/pull.htm
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Post by rodin on Jul 18, 2009 11:18:48 GMT -4
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Post by PhantomWolf on Jul 18, 2009 12:26:39 GMT -4
The collapse started before the Mechanical Penthouses fell since the core collapse was responsible for their collapse. At the time of the roofline collapsing, almost the entire interior had collapsed and so what fell then had little to no structural integrity to slow the fall.
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Post by rodin on Jul 18, 2009 15:31:19 GMT -4
The collapse started before the Mechanical Penthouses fell since the core collapse was responsible for their collapse. At the time of the roofline collapsing, almost the entire interior had collapsed and so what fell then had little to no structural integrity to slow the fall. What was the structure of the outside wall that collapsed. Did it contain steel columns? If so how could we see a steel lattice structure fall at such a speed?
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Post by PhantomWolf on Jul 19, 2009 5:03:51 GMT -4
The collapse started before the Mechanical Penthouses fell since the core collapse was responsible for their collapse. At the time of the roofline collapsing, almost the entire interior had collapsed and so what fell then had little to no structural integrity to slow the fall. What was the structure of the outside wall that collapsed. Did it contain steel columns? If so how could we see a steel lattice structure fall at such a speed? It was similar in construction to that of WTC 1 & 2. The reason it collasped is that when the centre core of the building collapsed due to the failure of colum 87, it took out the transfer trusses on the 5th-7th floors. With them gone there was nothing holding up the outer "tube" of the building so the remaining outer parts of the building above floor 8 started falling, the southern face first, followed by the north which ended up collapsing ontop of the pile. Once the centre core was gone, the outer core was a house of cards.
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Post by rodin on Jul 19, 2009 11:47:23 GMT -4
What was the structure of the outside wall that collapsed. Did it contain steel columns? If so how could we see a steel lattice structure fall at such a speed? It was similar in construction to that of WTC 1 & 2. The reason it collasped is that when the centre core of the building collapsed due to the failure of colum 87, it took out the transfer trusses on the 5th-7th floors. With them gone there was nothing holding up the outer "tube" of the building so the remaining outer parts of the building above floor 8 started falling, the southern face first, followed by the north which ended up collapsing ontop of the pile. Once the centre core was gone, the outer core was a house of cards. I don't care if there was nothing at all connected to the wall in question. It fell pretty much straight down, at free fall speed. Even if the only thing left standing was that wall, it could not have done this unless all resistance was simultaneously removed at every level. I am not the first to note this, my point is I have provided an easy proof of free-fall anyone can follow and replicate [quote/] 723 architectural and engineering professionals and 3976 other supporters including A&E students have signed the petition demanding of Congress a truly independent investigation.
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Post by gwiz on Jul 19, 2009 12:38:30 GMT -4
Do you understand the failure mechanism for a thin column? It will fail by buckling, in other words a bulge will develop and rapidly expand sideways while the parts above the bulge move downwards. Because there is nothing in a direct line to stop the part above the bulge from falling, it will do so at near free-fall speed.
I would expect at least one of your 723 engineers and architects to have known that. I learnt that at college and I'm not even a specialist structural engineer.
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Post by rodin on Jul 19, 2009 14:12:31 GMT -4
Do you understand the failure mechanism for a thin column? It will fail by buckling, in other words a bulge will develop and rapidly expand sideways while the parts above the bulge move downwards. Because there is nothing in a direct line to stop the part above the bulge from falling, it will do so at near free-fall speed. I would expect at least one of your 723 engineers and architects to have known that. I learnt that at college and I'm not even a specialist structural engineer. It will buckle at 'near free-fall speed'. You're kidding me, right? All of every vertical steel column buckled at free-fall speed (observed, not 'near free-fall speed') - this you actually claim as physically possible?
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Post by gillianren on Jul 19, 2009 15:15:14 GMT -4
I've always been curious about that "observed." If, as structural engineers (whom I trust more than just some guy online, bluntly) say, a lot of the collapse happened inside the building before the collapse seen from the outside, who's observing what?
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Post by gwiz on Jul 19, 2009 15:27:40 GMT -4
It will buckle at 'near free-fall speed'. You're kidding me, right? No, once the buckling starts, the column begins to lose its ability to take a compressive load, and the more it buckles the weaker it gets. It's a very rapid failure mode. Try it with a matchstick.
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vq
Earth
What time is it again?
Posts: 129
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Post by vq on Jul 19, 2009 16:05:28 GMT -4
It will buckle at 'near free-fall speed'. You're kidding me, right? No, once the buckling starts, the column begins to lose its ability to take a compressive load, and the more it buckles the weaker it gets. It's a very rapid failure mode. Try it with a matchstick. Actually, if the interior and/or other side of the building has been collapsing for a significant amount of time before the visible roof line begins to drop, it could actually accelerate faster than free fall as the already-moving structure pulls it down.
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Post by rodin on Jul 19, 2009 17:51:59 GMT -4
There is no mechanism where a buckling of anything could lead to a free-fall. And as to the inside or some of the inside of the building being pulled down first and then dragging the rest after it, either by physical connection or some sort of air pressure effect, the wall showed no sign of inward pull. It fell straight down, through its own footprint, with no sign of buckling or lateral force of any kind.
May I ask the connection of this forum to BAUT, since I was invited here from there?
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Post by LunarOrbit on Jul 19, 2009 19:28:32 GMT -4
May I ask the connection of this forum to BAUT, since I was invited here from there? You're a true conspiracy theorist... always looking for "connections". Other than the fact that some members of this forum are also members of BAUT there are no connections between the two websites. Just out of curiousity, what kind of connection were you expecting? That we get our funding from the same evil government agency?
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Post by PhantomWolf on Jul 20, 2009 2:30:55 GMT -4
The outer columns would provide little resistance to the collapse, The 40 odd feet would be free fall since the two stories there would have collapsed quickly with no resistance, after that the only resistance in the south wall is from the columns separating at the joints. With the north wall, the wall we see, it actually fell southwards, not straight down, it ended up folded over the top of the pile. In fact we know that the building didn't fall into its own footprint because it hit several surrounding buildings when it collapsed.
On top of this we really can't say how close to free fall the collapse was (note that free fall is an acceleration, not a speed or a velocity) because we don't have any film that records the end of the collapse. We can guess, and our guess is that it was close to what an object in free fall would have taken, but not exactly, and when you have any delay, no matter how small, then you have resistance.
The question you need to find the answer to is how much resistance woulkd the columns have created before the joints failed. While I am sure we have a few people here that could tell you exactly how to do that, I'd suggest that the answer is going to be in the ms, and over 40 stories that only adds up to a fraction of a second, something almost impossible to measure from the videos.
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Post by rodin on Jul 20, 2009 8:35:20 GMT -4
May I ask the connection of this forum to BAUT, since I was invited here from there? You're a true conspiracy theorist... always looking for "connections". Other than the fact that some members of this forum are also members of BAUT there are no connections between the two websites. Just out of curiousity, what kind of connection were you expecting? That we get our funding from the same evil government agency? Looking for connections is legitimate enquiry, no? No, I wondered if this forum was a spin-off of BAUT allowing a wider constituency of topics
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