1. BombDr

    BombDr Senior Member

    Because they are being fractured with explosive, and metal and explosive together cause fragmentation.
    Indeed, but why would you need explosives to destroy a building that had suffered an aircraft strike? It certainly was not recoverable and severely increases the risk of discovery.
    In appearance, perhaps. But this style of demolition requires significant removal of entire floors of supports down to the minimum required for the building to support itself. I'm not sure how to do this covertly.
  2. OneWhiteEye

    OneWhiteEye Active Member

    What passes for humor sometimes in places like this...

    Well, let's take the first case measured by Chandler:


    I estimate 7 seconds have elapsed since the piece initially started moving* until the frame shown here, where the measurement begins. Going back to the original tipping-only sim, the peak velocity obtained is high enough to account for Chandler's measurement, but it takes twice as long as the time available to get to that speed.


    So of course I'm looking at ways to speed the tip. But there are possible ways (see next ->).

    * I base the start time on the incredible WHAM occurring early in collapse when the upper section suddenly changes angle sharply and quickly. Even if it disintegrates as a result of this "impact", there has to be one hell of a reaction force. The moment the upper section kicks to the left in the image, this portion of wall kicks out to the right. Hard to imagine these two events as being unrelated since that's about where the bottom of the upper section would be, and Newton's 3rd requires some reaction.

    That is a potentially huge impulse.
  3. OneWhiteEye

    OneWhiteEye Active Member

    So the BAM sim is intended as a joke, but perhaps it's not so far off. The upper block snagging on that section of perimeter, if it did, would be a short lived high energy event, right when it is needed to account for an initial high tipping rate. Tiddlywinks under the thumb of God.
  4. OneWhiteEye

    OneWhiteEye Active Member

    If time permits (it probably won't), I'll pull out the PhysX game engine since Fydik doesn't do collisions per se. Impacts afford the possibility of pieces acquiring significant velocity even from components entering the collision at relatively low velocity. Like these:

    (large gifs)

    Basically, there is leverage at work, and collision can be a case of something being between a rock and a hard place, which may result in a forceful ejection.
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  5. Oystein

    Oystein Active Member

    I am up muuuuch too late and am really too tired for this mathy-physicky stuff, so I'll just throw out a couple of thoughts:

    1. The perimeter columns get heavier the lower you go in the building. Consequently, the center of mass of a tipping section is lower than half its height. This should speed up the angular acceleration under gravity, if the wall is stiff enough. OWE, can you include this in your model?

    2. I think it was @drommelsboef 2 or 3 pages ago who posted a maximum for the stored "elastic" energy of steel - something like 50 J/kg. I have not seen anyone pick this up and discuss. He argued that any piece of steel could at most be accelerated from 0 to about 10 m/s by elastic interaction (actually, the context was merely "bouncing" off a very large mass) alone. This feels sort of right, but I can't fully put my finger to it.

    3. Are you aware of DaveNMSR and his video showing 3 potential mechanisms to "eject" steel? One was bouncing (ricochet), the others were release of an elastically strained member ("bow and arrow") and snapping of a compressed member. I understand those do not fully apply to Chandler's 1st and 3rd examples, which have more to do with toppling, but could help understand the 2nd
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  6. OneWhiteEye

    OneWhiteEye Active Member

    Excellent idea. It'll be in the next runs. (Can't promise when those will be...)

    @drommelsboef also acknowledged "wedging" as a mechanism to produce higher velocities than the driving mass has, which is I think really important.
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  7. OneWhiteEye

    OneWhiteEye Active Member

    Likewise; the espresso at midnight means I got to this quicker than I thought.

    This has mass distribution in three sections: 1kg in top third, 2kg in middle, and 3kg bottom. The force travels as before, but it increases non-linearly as it goes down, starting at 100N and ending at 800N. The forces are updated every 400ms. When the force reaches the bottom, the top piece is severed and allowed to fly. A second later, the fixed hinge is removed at the bottom (this last part obviously doesn't matter to the dynamics of the severed piece) for interest's sake.


    As you expected, faster. It's now getting close to the lower end of range observed. Pushing harder makes it go faster, too, naturally. At some point, the ability of the wall to hold together that long and remain planar is question. It really does look like a wham could be responsible.
  8. Zett eL

    Zett eL Member

    Hi :)
    You all should start to think of the core columns folks.
    It´s not just perimeter walls tipping over, it´s core columns too. Adding some huge ammounts of energy to the lateral movements, I´d suggest. Being a catapult at some points, but also just pushing stuff within it´s own extreme tipping range.
    (Like tipping over all the way to WTC7 roof and causing a straight gash down to the lower floors and another bundle of core columns causing the damage at WTC7 southwest corner.)
    (And yes, I´m aware of the core structures lower half lasting longer than the rest of the towers - now think of the upper half; )
  9. trevor

    trevor Active Member

    what about the upperhalf? it didn't fall straight down like this.


    it through the midddle, and split out the perimeter walls like this.


    and here is the close up so you could see.


    I like to compare it to a Banana being peeled, because that's almost what it looked like. They weren't mostly fighting against the core columns.

    last time i used this source, someone lost their cool and flipped out, so here is your credit as well deserved.

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  10. Zett eL

    Zett eL Member

    I urge you to think of the core columns and your response is to talk about the perimeter walls?

    Why don´t you instead tell me what you think happened to the core columns?

    How about: "at least some of them tipped over like the ones in the following pictures"?


    My core columns hypothesis doesn´t even oppose your peeling hypothesis...
  11. Jeffrey Orling

    Jeffrey Orling Active Member

    First of all not all the core columns were the same... as in function. Sure they all carry axial loads... The FACADE columns were essentially identical to the one next to them (more or less) and they carried about 1/2 the outside the core floor load... the 24 perimeter core columns carried the about half the outside the core loads (and some inside the core floor loads too). The 23 core columns inside the core's perimeter carried only inside the core floor loads which were minimal and there were also on some floors a lot of shafts that were framed by the inside the core columns and so they had little to no loads from floors applied to their "side". ALL columns had axial loads from the column resting on it (above). The lower you go in the tower the more the axial load was compared to the side applied floor loads which were more or less uniform up and down the tower.

    Regardless... most of the columns failed from loss of bracing, not excessive loading. Almost all columns failed at the column to column end connection splices... which were way weaker than the sections they "joined"... and so you see full length columns in the pile of debris like pick up sticks. Those connections were unable to restrain lateral movement or force applied including Euler forces.
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  12. Zett eL

    Zett eL Member

    So whats the point?
    Do you agree with my idea, that tilting core columns added considerable energy (and mass) to the lateral movements in the collapses?

    Please watch the scene beginning at 1:05 in the following video.

    You can see a first wave of debris coming from high up in the building. This wave of debris however doesn´t reach WTC7.
    Then a second wave of debris emerges from somewhat lower in the building. And hits WTC7.
    In the following scenes in the video I pointed out, that it was a tilting core column that hit the roof of WTC7, causing that huge gash in its south face.
    The falling debris doesn´t reach WTC7, but the tilting core columns do.
    Think about it.
  13. Jeffrey Orling

    Jeffrey Orling Active Member

    Don't agree... it was the facade peel that reached 7wtc...
  14. Zett eL

    Zett eL Member

    So what you trying to say is, the object I highlighted at 3:03 in my video is part of the facade rather than a core column?

    And how about that other bundle of core columns, causing the damage at the sw-corner of WTC7? Also a part of the facade that somehow looked like core columns, not facade sections?

    Follow the object highlighted here:

    ...while watching the scene starting at about 2:20 in the following (different) video (slowmo advised):

    It was not peeling facades that caused the two damage zones at WTC7, it was tilting core columns.

    Just try to open your mind for this possibility and soon you will realize, that that´s what the pictures and videos show.

    Once you realized, that it was indeed tilting core columns that hit WTC7, you will easily find other core columns, tilting to other directions, too.
    And finally you might agree, that also some other alleged "flying" objects are most likely upper ends of other tilting core columns.

    So in regards to the thread topic I want to say:

    1. Many of the alleged "ejected" objects might in fact be upper ends of tilting core columns rather than ejected, flying objects.
    2. Some of the objects that actually did fly, including facade sections, probably received additional lateral force from those tilting core columns.
    Last edited: Nov 19, 2015
  15. Jeffrey Orling

    Jeffrey Orling Active Member

    The core columns that toppled almost all broke into 36' sections and mostly came straight down.. certainly not having the top sections fall over 412' to the SW corner of wtc. The facade of 1wtc was was 352 feet south of 7wtc and the core of 1wtc's north row of columns were 60' further to the south.

    NB that in the collapse of the core much of rows 500 and 600 were connected by lateral bracing running n=s and when these remaining columns toppled they appear to fall to the east and or the west... the shorter axis... much the way a ladder would fall.

    Look at beginning at 5:04 and you can see the "remaining" core does not fall to the north
    Last edited: Nov 19, 2015
  16. Zett eL

    Zett eL Member

    So, this is a 36´ section:
    And this is a 36´ section:
    And this is a 36´ section:
    And this is a 36´ section:

    And the object that hit the roof of WTC7, causing the gash, is not a perimeter section anymore, but a (flying?!) 36´core column section now? Or still a perimeter wall?

    And the bundled object that hit the sw-corner is not a perimeter wall anymore, but a (flying?!) 36´core column section now? Or still a perimeter wall?

    Dude, please start to adress the points I make, instead of just claimin I´m wrong.
  17. Jeffrey Orling

    Jeffrey Orling Active Member

    First of, don't call me "dude". Second you clearly have no idea what you are looking at. The ladder looking assemblies are col 501 and 601 and the bracing between them at 12' vertical spacing. The video you cited clearly shows the spire falling not to the north. The steel which fell to the north was the north facade peel.

    Attached Files:

  18. Jeffrey Orling

    Jeffrey Orling Active Member

  19. trevor

    trevor Active Member

    i heard lucky larry is such a demolition expert, that he was able to aim/angle the explosives to eject debris to hit wtc 7. now thats what you call, "Determination".
  20. Zett eL

    Zett eL Member

    Thats funny because in your picture theres not even a facade to be seen on which the core columns must be lying on.

    So do we take this as evidence, that neither facade nor core reached WTC7?

    I didn´t mean to offend you by calling you "dude".
    However, I´m kinda disappointed. I really just want to open yours and anyone elses eyes for the longish objects that seem to follow a path of tip over movement, reaching WTC7 but also tilting to various other directions.

    You prejudge me as a noob who didn´t take a closer look at the visual evidence, while in fact you are the one who doesn´t dare to take a closer look at the visual evidence.

    And whats the reason to exclude the core structure from any detailed collapse analysis in the first place? Give it a chance Mr. Orling.

    I cited two videos, both of which showing spires falling/tilting to the north...
    Last edited: Nov 19, 2015
  21. trevor

    trevor Active Member

    i feel like we saw plenty of debris hit wtc 7 in the video above...I find that the "type of debris" that hit it is irrelevant, and not even worth discussing. I don't think we are going to be able to figure out which or what type of columns hit the building, but as the video clearly shows, debris hit the building. Case Closed.

    Why is it important for you to find out what kind of debris hit wtc 7? did i miss something?
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  22. Jeffrey Orling

    Jeffrey Orling Active Member

    I have been studying the images and the plans and reading the 911FF and other sites since the beginning of 2010... I have produced scores of slides and calculations in an attempt to understand this event. What I do think I know is that the core columns of 1WTC did not fall / tip over and land on and damage 7wtc.

    I have my own theory to explain how these collapses happened. They were complex events and I agree with others on many aspects of the collapses... I don't think anyone as detailed the initiation phases to my satisfaction though various mechanisms of structural failure... components of the larger complex progressive process are well understood. We DO lack data from the buildings and most explanations are build on assumptions.

    I don't think the NW damage to 7WTC play a role in the initiation of the collapse. I don't use the term "ejected" as virtually all steel outside the footprint toppled over and away from towers or fell pretty much straight down.
  23. JRBids

    JRBids Senior Member

    I do not see anything that is in the circle you made, but smoke. I do see pieces of the facade flying off. I never noticed the pieces traveled so far. It is too bad the videos do not show the FRONT of WTC 7. It's hard to tell from the back which pieces hit 7, but it looks as if many pieces of the facade did. What difference does it make?
  24. JRBids

    JRBids Senior Member

    SO you believe what? Why are CTer, and truthers, so freaking COY? It looks to me you believe it was a controlled demolition. Whatever you believe you are going to go over the videos and photos looking for minutia and disagreeing with any opposing opinion. My fervent apologies if I am wrong, but why not come out and say what your theory is?
  25. Zett eL

    Zett eL Member

    I wanted to know what caused the straight gash in the south face of WTC7, so I watched videos of north tower collapse to find out. I realized some of those tilting core columns and began to wonder if one of those columns might have done that gash, it seemed to make perfect sense in contrast to the idea, that some flying debris caused that perfect vertical line, that gash of tens of stories height.
    And finally I found that sucker and the bundle that hit the sw-corner and quite some more to other directions.

    However, thats just how I came to my conclusions.
    What you indeed seem to have missed is this:

    So its simply too complex to include the core columns to the analysis? I mean, this is not like not taking the structural strength provided by the antenna into account. Its the core structure and you guys don´t even bother to go there, you don´t adress this important building feature at all. Since (all) others also don´t bother to include the core columns, theres no reason for you to accept additional explanations that might lead to a more comprehensive explanation?

    Well folks, I don´t wanna blame you for not seeing the visible at first glance. Take your time, but give it a chance folks. I´m not making this up and it won´t harm you. It will still be possible for you to believe in banana peeling or no banana peeling, controlled demolition or no controlled demolition and so on. It´s just about the core columns and how the tiltilng of at least some of them added mass and energy to the lateral movements, providing explanation for at least some of the alleged "ejections".
  26. Jeffrey Orling

    Jeffrey Orling Active Member

    hahaha you are wrong... I am decidedly not an advocate of CD, false flag and the inside job. On the other hand the technical explanations given likely were incomplete, inaccurate and missed things which may be important.
  27. Jeffrey Orling

    Jeffrey Orling Active Member

    I believe some of the 700 row toppled over. Parts of some of the spire broke off and toppled over. The very tall spire columns collapsed from Euler forces and broke at their splices. Imagine a stack of say wood columns one atop the other... if the buckles from euler forces it would break at the splices ... and probably at mid height and fall more or less straight down not topple.
  28. Jeffrey Orling

    Jeffrey Orling Active Member

    My "theory" or what I believe is off topic in this thread. I don't believe in CD... no evidence for that.
  29. tadaaa

    tadaaa Active Member

    I sympathise, as this thread is very technical in nature - but i don't read it as a truther versus official story thread

    and hence read the thread as a highly focused examination of the actual WTC collapse and the mechanism/forces contained within it - not what actually caused it.

    Obviously this is important, not to the world at large because it does not change the central narrative in any constructive way, but rather it may be important to people who are charged with creating building codes etc etc

    and some people feel like it is important to "get it right"
    Last edited: Nov 20, 2015
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  30. Zett eL

    Zett eL Member

    Ok, maybe I should start afresh.

    Although WTC7 is not exactly the thread topic, I want you all to focus on the damage WTC7 suffered from the collapse of the north tower for a moment. After all, WTC7 is supposed to have been hit by some of those alleged "ejections" from the north tower, right?

    So please take a look at the gash we can see in these pictures:





    Now even without looking at the videos of north towers collapse, what is more likely to be the cause of such pattern of damage?

    - multiple wall sections raining all over WTC7?

    - a single wall section that hit WTC7 at the roof and then slided all the way down without ever leaving the building?

    - something like a very tall core column section, tipping over on WTC7?

    Even at this point you should realize, that the peeling facade hypothesis may not be sufficient to explain this long straight gash.

    Now I would like to show a gif, unfortunately someone needs to tell me how to embed it first ;/
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  31. Zett eL

    Zett eL Member

  32. jaydeehess

    jaydeehess Senior Member

    You realize that with absolutely no evidence at all you have decided that a core column somehow fell on WTC7?

    Ok, I'll bite. How does a core column get to WTC7?
  33. jaydeehess

    jaydeehess Senior Member

    Where on it?
  34. JRBids

    JRBids Senior Member

    If something "tipped over" wouldn't it have still been lying there? If something "tipped over" how would it have caused such a gash? To me it looks as if something very large and heavy fell from a high distance and hit the top,, then pieces of WTC7 and the original debris fell through to the bottom. Looking at the photos I guess it is tempting to see whatever it is simply slicing through all the way from top to bottom evenly, but we have no way of knowing how far into the interior the gash goes.
  35. Zett eL

    Zett eL Member

    I realize that with absolutely no evidence at all some people have decided that perimeter walls somehow fell on WTC7, while video evidence strongly suggests it was tilting core columns that did the two most significant WTC7 damages zones.

    Aren´t you reffering to this:


    Well, how could a core column section which is tipping over on WTC7 get to WTC7 you ask? By tipping over on WTC7... :confused:

    Lying where? On the streets that can´t be seen on any pictures? Or underneath the WTC7 rubble after it collapsed itself?
    Well, we can talk about that issue, however I suggest to go through "my stuff" first...


    Gimme a chance folks, I´ve got so much to gif now :D

    I mentioned the following scene before:


    Look how the first wave of debris doesn´t reach WTC7, while a second wave emerging from somewhat lower does.
    This is not something we see in the Jenga clips or in OWE´s gifs - where no core column model was included. We see it in the actual collapse video, because reality included the core columns ;)

    I´m gonna present some more gifs very soon which should convince you, that the objects that hit WTC7 looked like core columns rather than wall sections.
  36. trevor

    trevor Active Member

    i've never seen those photos. do you have any without the editing/photoshop on it?
  37. Zett eL

    Zett eL Member

    Basically all pictures of that gash are taken from some few abc-news clips.
    Since the south face of WTC7 was covered in smoke, you never see the whole gash at one time. So people pieced pictures together to have it as complete as possible...

    You can see one of those few abc-clips at the beginning of my video:

    Or check the videos listed here:
  38. Zett eL

    Zett eL Member

    Let´s stick to my first gif for a second.
    It´s important to keep in mind, that we can rule out 1st wave debris objects to be the gash-maker.
    One can easily confuse that from different angles...

    Also this scene gives some good indications what exactly to look for in other footage.
    So let me highlight what I believe we should look for:


    Watch the gif some more times and keep looking for these objects.
    They seem to move just as one object at one point, but then they seperate from each other.
    There is one smaller thing highlighted in red which seems to be breaking off or something and then diverging from the rest which is highlighted in green. (I think the smaller object could be a deformed floor section, carried/pushed all the way by our actual gash-maker, highlighted in green.)
    So please look at the gif some more times to get a feeling for the highlighted objects, when they do appear and how they behave:


    Alrighty then...

    Let´s have a different angle:


    You see it don´t you? That toppling core column that almost seems to go for WTC7?
    Well, this one is NOT the actual gash-maker, it doesn´t even hit WTC7.
    However, the actual gash-maker can also be seen, looking like a bunch of crap falling synchronously in the foreground of what really looks like a tall toppling core column here.

    In the following picture, what I highlighted in orange would be the "obvious" core column that in fact is NOT the gash-maker, while the actual gash-maker is hidden in the green area (which should be the same green area from the other picture more or less):


    to be continued...
    Last edited: Nov 22, 2015
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  39. trevor

    trevor Active Member

    good work, but i think it's pretty difficult to discover which debris was the gash maker..im not sure if we'll ever be able to figure it out. What did Journal of Engineering mechanics or ASCE say about the debris hitting wtc 7?
  40. trevor

    trevor Active Member

    here's another video in slowmotion i found. i think it's the most clear one we can get, you can actually identify the types of debris