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  1. Thomas Nørgaard

    Thomas Nørgaard Closed Account

    I would expect to see something like this, when the collapse of WTC 1 started:
     
  2. Oystein

    Oystein Active Member

    Why?

    Do you consider that particular building to be a better scale model of the WTC1 than, say, any of the hundreds of non-failed demolitions you can dig up on YT? If so, what makes this particular building a good scale model of WTC1? If not, why do you post this here?
     
  3. Jeffrey Orling

    Jeffrey Orling Active Member

    Very much smaller building of reinforced concrete with rebars connecting slabs to columns making it a composite. Steel frames have steel members bolted together with the thin slabs composite with the bracing.
     
  4. Thomas Nørgaard

    Thomas Nørgaard Closed Account

    Just a simple illustration of the action reaction law. It would apply to buildings of any size. As it does to mountains, the moon, the planets etc.
     
  5. Jeffrey Orling

    Jeffrey Orling Active Member

    Thomas,
    This is flawed thinking. The laws of physics always applies but do not forget that different material and construction techniques will have different properties. If the tower you posted was made from wood do you think the collapse would look the same?
     
  6. Hevach

    Hevach Senior Member

    The physics of different materials are different. Action/reaction in its pure form only applies to point masses with inelastic surfaces around them. In a real interaction you need to consider far more forces and many aspects of the materials themselves - coefficients of friction, tensile strength, elasticity, hardness... Steel and concerete are extremely different in all of these categories.
     
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  7. Oystein

    Oystein Active Member

    So professional explosive building demolitioners try this sort of thing with great resilience, but fail again and again and again and again and again and again at making buildings of any size collapse?

    You mean that none of the buildings in this video collapsed, because of "the action reaction law"?

     
  8. econ41

    econ41 Active Member

    I am puzzled. What is the problem?

    Why would you expect the WTC towers to collapse differently to the way they did collapse? They didn't collapse in the same manner that a different building half a world away didn't collapse. Why should they?

    There is a lot of available photo and video material showing how the WTC Twin Towers actually did collapse.

    Both WTC towers collapsed in the same sequence of two distinct stages viz:
    1) Aircraft impact cuts some columns, starts fires, destroys fire fighting systems and blocks occupant egress routes >> a cascading failure results and the "Top Block" of the tower falls: THEN
    2) A rapid progressive failure leads to global collapse.

    Surely the real issue is understanding why they collapsed the way they actually collapsed. NOT why they didn't collapse the way they didn't collapse?
     
    Last edited: Jan 5, 2015
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  9. Keith Beachy

    Keith Beachy Active Member

    They had no clue how to destroy a building made up lots of rebar and concrete, there is no way it was going to look or act like the WTC. It failed to collapse because it was concrete with rebar. Did you see all the rebar at the top?

    The WTC had more floors above where collapse started, and the mass was too much for the floors below.
    Did you see all that rebar?
    Windsor Building in Spain survived due to a concrete core.
     
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  10. MikeC

    MikeC Senior Member

    I don' get what the "action reaction law" is supposed to be about in the case of building demolition at all - Thomas how is it you think the law applies to this?? :confused:
     
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  11. Trailspotter

    Trailspotter Senior Member

    True. A third blast later on finally brought the building down but failed to produce readily removable debris:

    PS All action happens in the first one and half minutes, the rest of the video are different views of the building before demolition.
     
    Last edited: Jan 6, 2015
  12. WeedWhacker

    WeedWhacker Senior Member

    I had an experience the other day that made think about "chaos".

    Take a 5-pound box of screws....and drop it from a defined height. See result.

    Take another 5-pound box of identical screws....and drop from the same height. Note result.

    This sort of "experiment" could be under more controlled conditions (arrangement of the screws within the box, etc)...but the final dispersion OF the screws on the floor? THAT is the 'chaos' factor.
     
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  13. econ41

    econ41 Active Member

    Yes. And the factors "five-pound", "box", "drop", "height" and "scattered" are not chaos. They are amenable to reasoning without the need to consider chaos. The chaos element is in the final dispersion into scattered multiple locations of individual screws.

    Translation to WTC collapse should be obvious.

    The chaotic aspects would include some elements of final resting point of structural components after the collapse ; also the specific timing or sequencing of the individual structural component failures in the cascade failure of the initiation stage.

    Neither of those is totally chaotic. Just some aspects are.

    And the bits that are partially chaotic are not critical to any significant argument. We can work out what happened without the "chaotic" bits getting in the way of reasoning.
     
    Last edited: Jan 6, 2015
  14. MikeC

    MikeC Senior Member

    Actually I have figures out what thtis failure has to do with the WTC - it proves conclusively that the WTC was not subject to CD - because CD doesn't wok properly!!:D:cool:
     
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  15. econ41

    econ41 Active Member

    Shucks. I missed the analogy. :oops:

    "If WTC collapses had been CD they would have arrested part way down. And needed a second stage."
     
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