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| Did sagging trusses cause the perimeter bowing?; SO WHAT MADE THE PERIMETER COLUMNS BOW? | |
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| Topic Started: Jul 17 2009, 08:46 AM (839 Views) | |
| Miragememories | Jul 17 2009, 08:46 AM Post #1 |
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From the RKOwens4 creation @ http://www.youtube.com/watch?v=bMZ-nkYr46w   The above images are captures from an RKOwens creation and based on his acceptance of the NIST WTC Final Report. What remains unexplained is "how and when" the new science backing the NIST collapse theory was developed? The trusses were in effect, horizontal lengths of structural steel attached to the perimeter columns at one end and the stronger and heavier core columns at the other end. According to the science I was educated in, if you heat steel it expands. Therefore, the heated trusses would have been expected to expand. But what happened when this truss expansion was resisted at both ends by the strong columns? In order to expand, the trusses had to bend. Bending is not the same as sagging. The trusses did not pull on the perimeter and core columns because they expanded and sagged. The trusses bent as they expanded and pushed on the perimeter and core columns. A bending truss is not the same as a sagging truss. A truss would have to heated to the point of losing all it's rigidity before it would stop pushing and take on the characteristics of a hanging steel chain. Until such time, no "pull" is applied to the attached perimeter and core columns by the truss. So what caused the observed perimeter column bowing? Core column failures. The necessary pull on the perimeter columns could only have occurred if the trusses, which were attached to the core columns, were pulled inward when the core columns began to also fail inward. The pull could also be achieved if the trusses somehow broke free from the core, which would result in the unsupported truss applying major torque to the perimeter column connection. Why would the core columns fail and what could cause the trusses to break connection with the core columns? Food for thought. MM Edited by Miragememories, Jul 17 2009, 09:15 AM.
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| mike_abcd | Jul 17 2009, 10:47 PM Post #2 |
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If the core columns r exploded (due to explosives) before the peripheral columns, the trusses will pull in the exterior to cause the bowing. The peripheral bowing doesn't prove if its due to due to explosives or due to fire. |
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| Miragememories | Jul 18 2009, 08:06 AM Post #3 |
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As I believe my original post made clear.
It established that the perimeter columns were bent inward. The NIST has endorsed the theory and conclusion that the connected trusses "sagged" and pulled on the perimeter columns, forcing them to bow inward. I've pointed out the absurdity of the trusses being able to "sag" and "pull" like a chain, so, if the bowing was related to the connected trusses, as would seem likely, something else must have effected the trusses in a manner that would make them "pull" on the perimeter columns. Only two possibilities come to mind. If the trusses broke far enough from their perimeter connections, the extended section would apply torque to the perimeter and make it bow. |__________| /_______ ._| |__________| Or, if the core column failed inward, pulled on the truss connected to it, resulting in the perimeter column connected at the other end being pulled inward as well. |__________| /_________/ |__________| Since the fires would appear to be woefully inadequate to accomplish either of these scenarios, it would seem logical to conclude that controlled demolitions in the core were responsible. MM Edited by Miragememories, Jul 18 2009, 09:21 AM.
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| DoYouEverWonder | Jul 18 2009, 01:35 PM Post #4 |
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I think if the trusses had started to fail, you would have also seen the fire breaking out on the floor directly above the trusses. That would have indicated that the fire was spreading and it was so hot, that it breached a very substantial fire wall. There is no evidence that this was happening at the time of the collapse. Actually, it was the opposite and FDNY was reporting most of the fires were going out, which is what you would expect in an office building. Even if a few trusses failed from the relatively localized fires, you would have only had a partial collapse. |
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| T3QuillAMocKINGbird | Jul 20 2009, 06:50 PM Post #5 |
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If the Trusses are sagging they are also stretching and lengthening too right? They can't bow and actually retain the same length and wouldn't they loose the tensile strength to cause a snap of a perimeter column. I saw a documentary last night on the History channel and it showed the 1993 attack and how that same amount of explosives oblitterated the side of the Oklahoma building. The columns could take this amount of damage at the base and there were no reinforcements left between columns. The columns stood like champs. These columns could withstand explosives but not fire? Of course this is at the basement where the columns are thickest. |
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| TDX | Jul 23 2009, 04:36 AM Post #6 |
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Hey, I'm the expert on the inward bowing.I could talk a few hours (days..) on that topic, so I'm unhappy to put it in short text...but I'll give it a try. The inward bowing theory as proposed by NIST is theoreticaly possible, but closer inspection of the actual events and photographs shows that the theory doesn't hold any water: The theory involves: aircraft impacts resulting in shotgun-like blast, the resulting shrapnels should destroy significant portions of fireproofing (tens of percents....50%...) then the resulting office fire should have caused elevated temperature in the trusses (500°C) the resulting restrained thermal expansion and heat-weakening should have caused rapid or more slow sagging (lol), the sagged trusses should pull in the exterior columns.......collapse problems: 1)The North Tower: The impact on the north wall resulted in projectiles removing the fireproofing in the southern half of the tower,................f***k it: to cut long story short: there was a half of a floor with lacking fireproofing (according to NIST) that half of floor did burn for 75minutes with no observable inward bowing of course the maximum of the inward bowing developed in the east half of the floors, where NIST predicts no loss of fireproofing and no high temperature, what's more the fire in that area started only 20minutes before the collapse however, the bowing develops here, with it's 1,5m maximum, in other wors: according to NIST story: the tower was brought down with 20 minute fire, which sagged a fully fireproofed truss for 3m.............. I will not go deeper, If I would want cover it I would have to write dozens of pages.....there are enormous problems with the NIST story, everything points out at the core columns the inward bowing was caused by cuts in the 1000,900 and maybe 800 row columns in both cases, with thermite/explosive combo at the impact floors, the basement levels and 105th floor (both cases) the north tower bowing could have incorporate cuts at the 75th/77th floor If you are really interested in that thema I suggest you to watch this: http://www.youtube.com/watch?v=iNS2Mld9v24 http://www.youtube.com/watch?v=yTqY_dld08g http://www.youtube.com/watch?v=-y2vgETA8gs http://www.youtube.com/watch?v=YoZY7lNRlSI http://www.youtube.com/watch?v=WPtAOtO1nTY http://www.youtube.com/watch?v=iM0KHh6uBRI http://www.youtube.com/watch?v=XvEThVxFAXc http://www.youtube.com/watch?v=zdO3RGelXJw (a little bit outdated, partially wrong video) The first 4 videos are a little bit hard to understand for new-comers, but don't worry.....the captions and pictures are enough to understand. It's a complicated subject, but now we can easily prove that the core columns cutting nanothermite/less frequently explosive charges account for the inward bowing...... Edited by TDX, Jul 23 2009, 04:42 AM.
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| chrisfarb | Jul 23 2009, 09:30 AM Post #7 |
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The only problem I have with cutting the columns is that it does not account for the pools of molten metal that were reported and the hot ground for months after the collapse. I still opt for thermite melting within each column as a better explanation. |
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| HeadLikeARock | Aug 30 2009, 06:42 AM Post #8 |
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Is this scenario a possibility? The floor trusses heated up and expanded, causing them to buckle as they pressed against the outer columns and the core columns. As the fires consumed the available fuel and moved to other areas, the trusses then cooled and started contracting. The cores being stronger than the perimeter columns caused the perimeter columns to be puled toward the core, causing the visible sagging. This seems to fit the observed data (gradual bowing which started some time after the crashes). |
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| Miragememories | Aug 30 2009, 07:43 AM Post #9 |
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If you apply heat to a length of steel, of course it will expand. As the floor trusses expanded, because they would be resisted by the core and perimeter columns, they would be forced to slowly bend. As the trusses cooled, they would contract and the amount of bending would be reduced. Meanwhile, the strong core and perimeter columns would remain effectively indifferent to this gradual expanding and contracting truss activity. You lose me HeadLikeARock when you use illogic to support your conclusion that this activity seems to fit the observed data. When the trusses cool and slowly contract, you appear to believe that instead of the trusses unbending, they will instead "pull", and with greater vigor than they "pushed". That the floor trusses, while using the stronger core as an anchor, actually pulled with such strength that the perimeter columns, which easily resisted the heat expanding truss "pushing", now, cannot resist the "pull" from the contracting trusses as they slowly cool? This seems to take the observed data (bowed perimeter columns), and place a totally illogical interpretation on it. Why do you ignore the more logical conclusion, that inwardly failing core columns, attached to the floor trusses would more likely cause such pulling and perimeter bowing? MM Edited by Miragememories, Aug 31 2009, 11:45 AM.
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| DoYouEverWonder | Aug 30 2009, 08:37 AM Post #10 |
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Of course the simulation leaves out the steel pans and 4" of concrete that were between each floor. It would screw up their simulation if they did. Also the 81st floor in WTC 2 had beams under the elevator hoists, not trusses. Edited by DoYouEverWonder, Aug 30 2009, 08:38 AM.
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| JFK | Aug 30 2009, 10:12 AM Post #11 |
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The scenerio would make sense if the truss attachment points were differently configured... For example if they were in this arrangement then yes it could have resulted as the official story states...  In all likelyhood had the trusses been arranged like that the building would have torn itself apart long before 9/11 due to sway. Anyway they weren't arranged like that, they were arranged like this : 
Edited by JFK, Aug 30 2009, 10:16 AM.
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| HeadLikeARock | Aug 31 2009, 11:38 AM Post #12 |
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That's true, I should have considered that. Intuitively it doesn't seem logical that if the trusses were deformed when heated (due to the relative strength of the perimeter and core columns) that it would be easier to cause the perimeter columns to bow inward rather than for a "reverse deformation" of the trusses to occur. Similarly, if the core columns where the trusses were attached were weakened, then presumably cooling would pull the core columns outward, rather than pull the perimeter columns inward? I'm wondering if there is also some other process at work here that I haven't considered. Edit to add: Is it possible that the buckling trusses lost sufficient integrity to support the concrete floors, and the extra stress on the columns caused the bowing? Edited by HeadLikeARock, Aug 31 2009, 11:57 AM.
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| Miragememories | Aug 31 2009, 01:36 PM Post #13 |
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The trusses are stabilized by interconnection. To make them pull those powerful perimeter columns inward would require the torque from many truss-core disconnects - or pull-in from an "induced" core failure.  MM Edited by Miragememories, Aug 31 2009, 01:39 PM.
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| Miragememories | Aug 31 2009, 02:40 PM Post #14 |
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Here's the complete series of screencaps for that locked off camera shooting WTC2. Each image is at a 1/3 second interval, with the whole sequence covering almost 7 seconds.  MM |
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| hamba | Sep 3 2009, 09:29 AM Post #15 |
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Can someone please explain to me the difference between sagging and bending? |
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| Miragememories | Sep 3 2009, 10:38 AM Post #16 |
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Ropes, chains etc., materials that are not normally rigid when extended, will increasingly sag under an increasing gravity load. ie. more clothes added to the line. Rigid materials, depending on their elasticity and composition will bend or snap when additional gravity load is added. Rigid material, like that found in a steel truss, snugly placed between to immovable objects, will bend when heat expanded, or in the absence of heat, if they are over-loaded beyond their designed gravity load tolerances. The heated truss bends in response to expanding against the immovable columns. It doesn't push (expand against) and pull (sag) at the same time. MM |
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| RosaL1919 | Sep 11 2009, 05:32 PM Post #17 |
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@TDX Did you have something like this in mind? I wonder whether column cuts in the hit are really necessary. If the structure is overloaded, collapse will start at the weakest point, the hit floor. If the planes were not really necessary, then why banking the planes in order to maximize damage? I think they needed maximal damage at the perimeter columns and transferred the weight of some of the core via the head truss on the perimeter. So they needed cuts at the top and at the bottom. I remember that your calculations suggested a bigger mass of the top than expected. Here I show how they might have increased it. They used the mass below.     Edited by RosaL1919, Sep 11 2009, 05:38 PM.
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| noeffects | Sep 11 2009, 06:54 PM Post #18 |
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I think TDX got sent to his room for a time out... it says he is not banned...surprised he is not back yet. |
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