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| Inward Bowing; interesting videos | |
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| Topic Started: Mar 24 2008, 01:45 PM (1,127 Views) | |
| TDX | Mar 24 2008, 01:45 PM Post #1 |
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(it shows that the inward bowing isn't proof of fire-induced collapse...) http://youtube.com/watch?v=m3CFlRVMs8g http://www.youtube.com/watch?v=iNS2Mld9v24 http://www.youtube.com/watch?v=yTqY_dld08g http://www.youtube.com/watch?v=-y2vgETA8gs Edited by TDX, Mar 25 2008, 09:24 AM.
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| Avenger | Mar 24 2008, 08:27 PM Post #2 |
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How can sagging floors pull on perimeter columns? And what about the core columns? |
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| Miragememories | Mar 25 2008, 08:20 AM Post #3 |
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Sagging floor trusses pulling in perimeter columns are an essential part of the NIST hypothesis as to why the Towers collapsed. NIST is merely interpreting weak observations in a manner that allows for useful assumptions. Without these assumptions, the NIST Official Story falls flat on it's face. When a prestigious government organization like NIST goes into an investigation with the conclusion already resolved, it's just a matter of combining multiple test results and assumptions. Feed and tweak these into the computer model until collapse initiation occurs. Even with all this, the model only succeeds when the worst case parameters are fed into it. MM |
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| NK-44 | Mar 26 2008, 12:04 PM Post #4 |
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And there goes NIST inward pulling theory  Unfortunately, it's only on German, or to say better, the English version has not the comments of the narrator yet, whithout it it's hard to understand everything. But I know the guy who made it and hope that an English version will be soon online. And there are some more chapters, which aren't online, for example about the WTC Basement-Explosions, which is the best made on this part ever. The whole movie is very interesting and made in a professional style, and hope it will be available soon. Though the name of the movie is "The North Tower", also other interesting stuff is examined, to mention "Al-Qaida"-Propaganda-Videos (Ch 6a: hands-hands+symbols-hands-massmurder!) or the story of the "living pilots", Alomari, Bukhari, etc. Really good that this has finally made it into a watchable format (Ch6b - Alomari and Co , first part is in the second half of Ch6a). |
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| Headspin | Mar 26 2008, 12:16 PM Post #5 |
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how can a sagging floor pull the columns inward? in order to pull there needs to be a force, what force is there to pull that didn't exist before the collapse? this is basic applied mathematics. are they saying the floors gain weight as they sag? The inward bowing is more likely evidence that the core was collapsing, pulling in the perimeter columns. Edited by Headspin, Mar 26 2008, 12:17 PM.
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| exponent | Mar 26 2008, 12:32 PM Post #6 |
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I think you should possibly learn a bit more 'applied mathematics' (mechanics) if you think that a floor sagging does not change the forces being exerted. Think about it in this fashion, place a plank of wood across a gap and the forces transmitted are (not entirely but mostly) vertical into the supports at either side of the gap. Now anchor a chain between this gap and stand on the middle of the chain. How are the forces applied now? edit:
So three youtube videos supersede hours of modelling and hundreds of pages of text? Clearly you are not taking a balanced position. Edited by exponent, Mar 26 2008, 12:33 PM.
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| NK-44 | Mar 26 2008, 12:45 PM Post #7 |
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Yes, caused by load redistribution due to failing core columns. NIST takes some pictures, observes an inward bowing, and concludes from that, that this inward bowing is the cause of load redistribution leading to "inevitable" global collapse. So they just confuse cause and effect. The inward bowing is not cause, but effect of load redistribution. But this is tricky, as both theories, NIST's sagging floors pulling them inward, or that due to load redistribution from failing core columns the perimeter columns were pulled inwards, look the same: perimeter columns bowing inward. But for NIST's theory to be correct, the greatest bowing should occur in areas where the highest temperatures could be expected, and not in areas where this was not the case and even fire protection wasn't dislodged. Whereas the other theory does fit with bowing in areas where fire was not severe, or fire protection removed. The second theory, not NIST's, matches the observable data. NIST also misleads in its timeline about when sagging occured in the North Tower, they placed it later. They did so because with later occuring of bowing they could it better connect it to, and claim it to be, the initiation event. There also other points made in the clips, I hope you understand them though its on German. |
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| Miragememories | Mar 26 2008, 12:49 PM Post #8 |
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Hmm So in other words you judge based on quantity rather than quality? MM |
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| Miragememories | Mar 26 2008, 12:51 PM Post #9 |
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Excellent work NK-44. MM |
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| exponent | Mar 26 2008, 12:54 PM Post #10 |
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Nope, I referenced both. Modelling is superior to a youtube video. Please don't tell me you're trying to suggest that NCSTAR 1-6 is of less quality than those 3 youtube videos? edit:
Please actually read NCSTAR 1-6, it might surprise you! Edited by exponent, Mar 26 2008, 12:55 PM.
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| NK-44 | Mar 26 2008, 01:00 PM Post #11 |
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Damn, you beaten me. Exactly. So if an argument is wrong, then stating it on hundreds of pages makes it right? Maybe you didn't get it. The three clips deal with data provided by NIST. Should the narrator first read through all the hundreds of pages before going into this? Make an argument why the theory that core column failure causing load redistribution could not have caused perimeter columns pulling inward, is wrong. That's worth a debate. Not your knee-jerks responses making you looking like a NIST-cultist. It's clearly you who is not balanced. |
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| NK-44 | Mar 26 2008, 01:01 PM Post #12 |
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Once again, you present no argument. Just an appeal to the authority of NIST. |
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| exponent | Mar 26 2008, 01:04 PM Post #13 |
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I mentioned quality, please re-read what I said. Furthermore these three clips do not deal entirely with NIST, the claim that the floors would have to have sagged up to 3m is not NIST based and I am not sure of its origin. Regardless they do not present any calculations, any expert accounts (that I can tell) nor simulations nor even a coherent hypothesis (probably because my German is terrible :))
Please see http://forums.randi.org/showthread.php?t=107267
So accepting three youtube videos over NCSTAR 1-6 for example is perfectly balanced or not? Please tell me. |
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| exponent | Mar 26 2008, 01:05 PM Post #14 |
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You ask questions to which the answers are easily available. When I first started posting here I dug out every NIST reference needed and tried to explain things. This is clearly ineffective so I leave it to you to do your own research. |
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| Miragememories | Mar 26 2008, 01:16 PM Post #15 |
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Unfortunately that's about all you ever do. Cut 'n paste the works of others while avoiding any real discussion. You rarely risk explaining anything using your own point of view. You have to NISTify every argument. It's a constant reiteration of the NIST report that you cocoon your beliefs in. Heaven forbid you add some original thought to the discussion. MM |
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| exponent | Mar 26 2008, 01:21 PM Post #16 |
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How quick you are to forget when I offered to explain the collapse of WTC7 as best I could and you simply dismissed it without reason. Have you resorted to personal attacks so soon? Why don't you just address my questions and claims as I politely do to you? |
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| Miragememories | Mar 26 2008, 01:38 PM Post #17 |
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Yes that WTC 7 post where you actually explained what you believe occurred, "in your own words", was a shocking departure from your usual style. Please link me to any response that suggests I dismissed that post without giving reason??? MM |
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| NK-44 | Mar 26 2008, 01:43 PM Post #18 |
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Yes, as I said, without the narrator's comments it's hard to get it. And to the experts, you linked to the JREF expert Newton's Bit, who thinks that single column failures in general lead to progressive collapse. Please, I don't need such experts. I've asked some architects (not in relation to 9/11), and they laughed about such a statement. Don't believe me? Try it for yourself. That's not how collapses, or demolitions!, work. Only one point regarding NB presentation:
So the connection bolts were not exposed to fire? And they weren't heatened by the fire, though even being in a horizontal position to it? And this heating did not cause gradually weakening as you state for the columns to have happened? And this gradually weakening would not reduce their ability to withstand forces of 5kips? So that is really reasonable to assume? But wait, I'm not the expert.... |
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| exponent | Mar 26 2008, 03:53 PM Post #19 |
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That's quite understandable, and I will not make any solid judgements without hearing everything.
No, i've linked to the Structural Engineer Newtons Bit who knows and can show (and has done) that single column failures will lead to a global progressive collapse in most low rise buildings. He does this for a living, your dismissal of his expert credentials are irrelevant. How about Frank Greening, Newtons Bit, Gregory Urich etc
Architects are barely structurally trained, ask a structural engineer and document it, I am very interested in what happens.
For the love of god READ THE NIST REPORT. This is all explained, calculated, horizontal and vertical total force capacity are given for each different truss seat type. |
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| NK-44 | Mar 26 2008, 04:47 PM Post #20 |
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When he stated that buildings fall due to single columns failure he did not make an distinction due to the height of the building, but to their purpose, or to say better to their ownership. He stated that in non-government buildings single column failure leads to collapse (so I guess he does not subsume WTC 7 under the label government-building ), that was in the olf LCF, I don't know what else he stated regarding the height, etc. But he made this statement here, so structural engineer hin oder her, doesn't change that most people, including architects (of course they have no clue about buildings structure once they are in conflict with your NIST-bible, and therefore could be dismissed), regard this statement as a joke. But let's not argue about NB expertise, besides his notions about single-column-failures, which he brings up to defend the defendless (i.e. WTC 7 collapsed due to single columns failure caused by fire), I have no doubt that he knows MUCH more than I do about such stuff.
Again an mindless response. If you're not able to response in any other way than with your stupid "read NIST" comments, just let it be and look for another forum where you can troll. Everybody here knows that NIST investiagted the WTC collapse and also where to find their reports. So let's summarize: You haven't made any point (other then linking to the work of others) to refuse the theory that load redistribution could have been the cause for the columns to bow inwards. |
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| exponent | Mar 26 2008, 06:14 PM Post #21 |
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I may have remembered incorrectly, if so I apologise, regardless I defer to his authority when it comes to structural calculations.
Architects are not engineers, can you give me an example of an engineer disagreeing with him on this topic? I am aware of the members of ae911truth and I eagerly await anything they produce.
This is not trolling, you are asking questions which the NIST report answers in full. I am not an engineer, I do not have a degree in any scientific discipline and as such I can provide no better answer than that in the NIST report. If you have read the NIST report and disagree with a part of it then you should quote that specific section and make it clear what you disagree with.
Indeed, but not everybody has read them, even those that argue against them.
I am not qualified to make any such points, Newtons Bit and the other engineers at JREF are qualified and have provided the calculations to show that only floor truss heating can explain the inward perimeter bowing seen in photographs. Why exactly is it wrong that I point out the calculations of people more qualified, experienced and educated than myself? If you disagree with them you can take it up here or with them, I will defend my interpretation of their statements / calculations if required. |
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| NK-44 | Mar 26 2008, 06:48 PM Post #22 |
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So if you don't have anything to contribute other than this, then I suggest we ask the admins of this forum if we could make a pinned thread where we put in links to NIST and NB and other experts you feel necessary for to make an argument from authority, and then you leave this forum. It's not that people here want to discuss things with you when at the same time you say you're not able to discuss such things. When we have the feeling that we need a parrot, we will call you! |
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| Headspin | Mar 26 2008, 07:29 PM Post #23 |
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Even if the floor becomes totally chain-like/rope-like, how does the rope-like-floor pull in the perimeter columns? the only pulling force is the weight of the floor/chain itself, in your analogy you have asked me to stand on the chain, but that would increase the force to floor_weight+my_weight, we are not dealing with an increase in floor weight, nor are we dealing with a rope-like-floor, we are dealing with a sagging floor, or a floor with a slight curvature. If the central column structure fails and moves downwards, i can understand how the connecting saggin floor would pull in the permieter columns, but (correct me if i am wrong) what is being suggested is that the act of floor sagging itself pulls in the perimeter. |
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| NK-44 | Mar 26 2008, 09:08 PM Post #24 |
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Thats a good question you bring in here, Headspin. The perimeter columns have to carry the load from the structure above and from the floors. Now an additional force was applied to them when the heating caused the floors to expand, hence they pushed against the perimeter columns. This energy acting upon the columns wasn't there before, is the energy from the fire, and therefore an additional force acting upon the columns. But they resisted this force and instead of bowing outwards, the floors could not expand and therefore began to sag. Now there is no additional force like the expanding floor acting upon the columns which wasn't already in place before. As you said, there was no increase in floor weight. So this columns, gradually weakend through heatening, managed to resist the additional expanding force, but failed to resist the weigth of the floors they were built for and were pulled inward. And the bolts, which were even more heatened than the columns (at least if we apply reasonable thinking), managed not to fail. Incredible. So what additional forces affected the columns which weren't there before? That it could all be explained due to fire makes no sense when we take into consideration the fact that bowing occured also in areas were fire was less severe and fire protection in place, therefore the sagging-theory does not fit with the observations. You named it, central columns fail and causing the perimeter columns to carry more weight than they were built for. Which causes them to bow. But of course this explanation is not consistent with the official version, as the question would be: what caused central columns to fail, especially when we consider the timeline? What made the core columns fail shortly after the South Tower collapse, which resulted in bowing of the south wall? Of course the collapse of the South Tower would be a good point of time to set off some explosives at certain central columns. All reports of explosions by firefighters and others could then be dismissed as misinterpretation of the collapse of the South Tower. (Similiar to the (not-jet-fuel-)explosions in the basement, which are dismissed as result from the plane impact). But something happened inside the North Tower when WTC2 collapsed. Fire on the 105th floor (which NIST never examined, because their task was it only to examine the areas in fire  ), reports by observers from a helicopter of south wall bowing shortly after WTC2 collapsed and some others which need further investigation.There is no evidence for NIST's theory, even if we concede that it would be theoretically possible for sagging floors to pull the perimeter columns inwards, the observed data is not congruent with this assumption. And that NIST hides the evidence for inward bowing occuring just after the South Tower collapse, and places it a few minutes before collapse took place, is telling. With shortening the timespan between the occuring of bowing and collapse, they tried to implicate a connection between both events. But when bowing occured almost half an hour before collapse, the notion that both events are "inevitable" connected could not have been sold to the public as easy as it was. |
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| exponent | Mar 27 2008, 09:04 AM Post #25 |
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I apologise, in my analogy I should have pointed out you stand on the plank of wood too, the weight does remain constant but the direction of the forces changes. When you are standing on the wood it is storing some energy in elastic strain and applying a force upon the two anchor points. In the case of the chain even though the mass stays the same, the forces it exerts seeks to pull the anchor points inward. The situation in the WTC was a combination of these, trusses initially expanded as they heated and pushed out slightly. Then as web diagonals failed and they reached higher temperatures they sagged further. As they are no longer rigid and transmitting the forces to their anchor points they behave more like a chain, they pull inwards on their supporting seats. This would be further exacerbated when fires died down and the steel was left to cool and contract.
It's the act of floor sagging and some heating of the perimeter columns, at the time of failure for WTC2 I think the total deflection of any aspect of the core didn't exceed a foot. |
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