1. Jeffrey Orling

    Jeffrey Orling Active Member

    The structure is the key to how and where is collapsed in my opinion. I believe the massive trusses were site built and bolted together. Those structures spanned the substation because the axial load path could not pass thru Con Ed. This is the more likely location of the failures which brought the building down. FEMA and the building's engineer Cantor thought this was the place to look. My hunch is that "politics" played a role in not scrutinizing the structure down there.
     
    Last edited: Sep 7, 2017
  2. Jeffrey Orling

    Jeffrey Orling Active Member

    No I don't... I am not an forensic structural engineer. I find the NIST explanation was a fishing expedition more or less.

    I "believe" my own pet theory which I came up with years ago called "Transfer Truss Failure".
     
  3. James Ice

    James Ice New Member

    Hey Jeffrey - I'm just intersted, been reading the thread interesting in light of Hulsey's talk yesterday. One expects Hulsey, when he releases his full report, will address your pet theory. If he shows it could not have happened would you be persuaded?
     
  4. Jeffrey Orling

    Jeffrey Orling Active Member

    I seriously doubt he will address TTF... There was no fire data from that region of course and people even dispute (without basis) that diesel could have burned.... and be a source of fuel for the fire.... the region had massive fresh air grillage on the North side with NW winds that day as well.

    The decision to use transfers was political because 7wtc could not have been built without them. IMO it was insane to build over the sub station when available vacant land was just across West Street at the time. Air rights were cheaper... Con Ed made out and the engineer designed a Rube Goldberg to hold the tower up above the sub station.
     
  5. Mick West

    Mick West Administrator Staff Member

    All Hulsey did is show that if you model a part of WTC7 in a different way to NIST, and run the model a certain way, then the key girder does not fail.

    This does not prove that the girder could not have failed. Nor does it prove that the building could not collapse due to fire. Any engineer familiar with complex simulations should be able to see this. Unfortunately the conspiratorial public may not be able to.
     
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  6. Mick West

    Mick West Administrator Staff Member

    Has Hulsey posted his slides anywhere? Or any of the images from the talk?
     
  7. Oystein

    Oystein Active Member

    Publish data and slides? Things to read even? You gotta be kidding, Mick! They do real science! I.e. things you can post on YouTube ;)

    Speaking of which: Here are two video uploads of the presentation - the first, I hear, has better quality, but I am not sure how long it will remain online:

    1.) https://cdnapisec.kaltura.com/index...id/36513372/entry_id/0_nglk89c0/embed/dynamic

    2.)

    Source: https://www.youtube.com/watch?v=vMV8E_83NiI


    I am not sure when I will take time to watch this, and I fear I won't stand watching it from beginning to end, let alone annotate the talk.
     
  8. benthamitemetric

    benthamitemetric Active Member

    Not available on AE911Truth's site or the WTC7 Evaluation site yet.
     
  9. mjl

    mjl New Member

    I remember his first presentation about one year ago, when he stated that fire cannot be the reason, just in time for the 15th anniversary of 9/11. The only evidence he had was a simulation with some results differing from NIST's investigation by a factor of two. For me, it sounds ridiculous to make such a far-reaching conclusion based on so little evidence.

    And I am quite disappointed that all he has to present now, after more than two years of "evaluation", is more or less the same category: criticize details from the NIST investigation, but keep away from stating or evaluating own theories. That's completely different from the initial announcement from 2015.
     
  10. benthamitemetric

    benthamitemetric Active Member

    I don't know why you take that away from my comments. Can you please cite the specific comments where I stated or implied that?

    I think NIST pushed the boundaries of the field of forensic engineering via finite element modeling and came up with a reasonable approximation of one of the many ways in which WTC7 could have failed due to the observed fires. Their model, which they never purported to be a definitive, hyper-precise account of the collapse, is a reasonable high level approximation given the scale of what they were modeling and the incredible uncertainty surrounding key model inputs, including, but not limited to:

    1. No one knows and no one can know the exact condition of WTC7's structure pre-collapse (was all fire insulation properly installed and maintained, were all parts free of defects, was there any damage to the structure from modifications or construction errors, etc.?).
    2. No one knows and no one can know the exact fire loads throughout the building.
    3. No one knows and no one can know the exact progression of the fire throughout the building.
    These are HUGE unknowns. NIST did its best, but NIST did also acknowledge these unknowns and others explicitly in its report, and, appropriately, NIST's conclusion was not stated as a certainty.

    Others have also modeled the building in depth and found different possible collapse modes given different assumptions about the above points and other factors. The report that I believe does the best job to date in taking into account all info re the condition of the building is the Weidlinger Associates' expert report that was prepared in connection with the Aegis Insurance ligitation. That report (which was one of only three engineering research projects in the world to receive an ACEC Diamond Award in 2015) was in response to the plaintiffs' expert report in the same litigation and I believe persuasively corrected several issues therewith. Notably, however, both reports AGREE on situations in which the collapse would occur due to fire; they merely disagree at a high level as to whether the proximate cause of the collapse in such scenarios is attributable to negligent design/construction. (By the way, the reason AE911Truth has never told you about these reports, despite their availability for several years, is because AE911Truth is not interested in you or anyone else actually knowing the truth.)

    Again, however, know one can know for certain exactly how and why it collapsed because of the incredible uncertainty in the input variables. If anyone tries to tell you they know for certain, it's because they are lying or they have failed to grasp the difference between a simplified model based on certain imperfect assumptions and an incredibly complex real world event. If Hulsey wants to say that he used slightly different assumptions than NIST and saw a few inches of different movement in one single element of the building and therefore fire couldn't collapse the building, then I'm pretty sure he falls into the former category. In any case, it's incredibly poor engineering and reasoning.
     
    Last edited: Sep 7, 2017
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  11. James Ice

    James Ice New Member

    Yeah I think you're right - that was quite a limited presentation. But then again he does make it clear that full report is yet to come. Also, when you say all he did was model it in a different way to NIST, to be fair he goes into a lot of detail about the about the nature and importance of the differences. To be honest, I think he establishes that NIST's model is wrong. But as you say, at this point he does no more (!) than that.
     
  12. Oystein

    Oystein Active Member

    Quoted for truth.

    Also, never forget that AE911Truth and Hulsey broke promises, and do not mention these promises any more! They remove the promises from their project page, lest any truthers find out they have been broken!
    AE911Truth is staunchly determined NOT to let their donors know any truth.

    And this is why submitting to a real, refereed engineering journal of actual repute is one of the promises they quietly shelved and broke without revisiting.
     
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  13. Mick West

    Mick West Administrator Staff Member

    These uncertainties are key. There's another, somewhat harder to explain set of uncertainties in how well the simplified computer models reflect physical reality even if the building were built 100% conforming to the blueprints. When you model very limited regions you can use higher resolution, but even then it's still an abstraction that may respond differently in reality. Individual connectors can be modelled like this:
    20170907-083313-xkyde.

    Notice the size of the grid on the steel members. This is similar to the resolution of a photo. You can use higher resolution to get more accurate results, for example:
    upload_2017-9-7_8-46-12.
    (high resolution model from an unrelated study)

    Those detailed approaches are referred to as micro-modelling, and are great for studying the theoretical response of individual connections or assemblies in detail. But they are computationally expensive, and not practical for studying entire buildings. So there you use the macro-modeling where connections and members are set up as simple nodes (a point or set of contact points) that have a range of numbers associated with them - how much force they can resist, how much they can deform, when they will fail.

    Hulsey refers to these connections as nonlinear springs. Meaning the stress/strain curve is not a straight line (stress = force applied, strain = displacement or deformation). These are mathematical models, like
    upload_2017-9-7_9-13-48.

    They can be applied to a simulation in various ways, but they are basically abstractions and simplifications. Macro models of individual connections can be created using micro models to find the response curves. But if you run a simulation in micro and macro then you are unlikely to get the same result.


    upload_2017-9-7_9-15-7.

    You can simplify even further, and consider some connections as "fixed" (meaning they are infinitely strong and never twist or break).

    The point being that when you run a simulation on an entire building, like WTC7, you are going to have to make massive simplifications to the model to get it to run in a manageable time.
     
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  14. Mick West

    Mick West Administrator Staff Member

    Note though that there's not a hard line between micro and macro modelling. Macro can refer to just a decrease in resolution. There can also be hybrid approaches.
     
  15. benthamitemetric

    benthamitemetric Active Member

    Great points, Mick. I recall that one of Hulsey's early claims re the superiority of his model to NIST's was that he would model all connections in the building as nonlinear springs, whereas NIST only modeled certain connections near and around column 79 in such a away for the purposes of its collapse initiation model. As you say, modeling them all is computationally expensive (NIST's models already took months of compute time in the aggregate on what were at the time high end work station clusters--a fact that always made me chuckle when random people claimed they wanted to download and play around with them) but, given the increases in computing power in the last 10 years, that would be one area where the model could potentially be improved. Of course, as you point out, even improving those connections by degree does not mean they are completely accurate and there is always more resolution and precision you could tease out of them with more compute time. At some point, however, you have to stop modeling and accept some error in your final calculations as a result, and so the degree of resolution of each element is certainly another huge source of difference between collapse models.

    I wouldn't be surprised if Hulsey, if he actually added all of the connections throughout his global model like he planned, actually added more error to the model than he removed, given that the vast majority of those elements shouldn't have had any impact on the collapse initiation mechanism.
     
  16. Mick West

    Mick West Administrator Staff Member

    Hulsey describes the micro->macro process at 56:30
    20170907-095705-agn2x.

    The complex micro model of the connection is converted to a response curve, which is then used as the macro model for any connection of that type.
     
  17. Mick West

    Mick West Administrator Staff Member

    From NCStar 1-9 page 460 (pdf 526)


    And page 544 (pdf 610)


    Processor speed has not vastly increased since then. They were using 2.4 and 2.6Ghz, and processors top out around twice that now, typically around 4.5 Ghz for a high end workstation. However you'd now get far more cores (12 vs. 2) and other components like memory and drives are faster (plus you get more memory, which also speeds things up). There's also a move to shift more processing power onto graphics cards, or dedicated physics cards based on graphics cards. But that requires different software to take advantage of.

    But with a similarly priced system using the same approach as they did back then it's probably going to be 10-20x as fast.

    An increasingly common approach is to rent a chunk of the cloud, where you can get literally hundreds of computers working on your problem, and if set up correctly you should be able to solve it in far less time (hours vs. weeks).

    Did Hulsey ever describe the type of setup they used (other than software)?
     
  18. John85

    John85 Member

    I'm sure you're aware of some of the ways that Hulsey's model differs from NIST's. Are you neutral with respect to these differences and the influence they have on the accuracy of the models' predictions?

    NIST's omissions and errors line up to increase the movement of girder A2001 off its seat on column 79:
    • Column 79 modeled without side plates obstructing the girder
    • No stiffeners on girder A2001 that would reduce buckling under thermal expansion of beams
    • No shear studs on the girders that would tie them into the concrete slabs. Concrete slabs would have expanded slower than the girders, reducing their expansion in the process.
    • East columns fixed in place, directing all thermal expansion of the beams towards column 79
    NIST was pretty proud of their simulation:


    https://www.nist.gov/el/faqs-nist-wtc-7-investigation

    The sophistication of the model, the length of time the study took/resources available, the claim to have discovered a first in the history of building collapses, and the reporting of safety recommendations to industry based on this discovery, mean it is reasonable to assume that close attention was paid to the initiation sequence at column 79. They were confident of their conclusions. Were the omissions and errors upon which the initiation mechanism was predicated accidental, or fraudulent?
     
  19. Mick West

    Mick West Administrator Staff Member

  20. Oystein

    Oystein Active Member

    You tell us once you find evidence for or against BOTH "omissions and errors" and "fraudulent" (similar to how benthamitemetric and myself documented meticulously the broken promises by AE and Hulsey).

    Until then, I'd appreciate if you refrained from poisoning the well with suggestive questions.
     
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  21. Keith Beachy

    Keith Beachy Active Member

    Fraud? No, it is called engineering. Did you know the aircraft you fly are model assuming a flat earth? Why? Because the EoM for flight can be modeled and linearized using a flat earth model, and the terms associated with a spherical earth can be ignored. What you call fraud is really called engineering, where engineers can simplify a model because the stuff you call omissions are not needed; like the terms related to the earth spinning, lift related to the spinning earth, are insignificant below MACH 3.

    The claim of fraud is based on what? Stuff googled from the internet, 9/11 conspiracy theorists with no evidence.

    Don't fly, it seems based on what you call fraud, all the flight systems we design are a fraud. We left out terms, okay, my professor showed me terms we left out.

    Don't believe engineering assumptions...
    Here is an example how engineers and scientist do it.
    http://www.aerostudents.com/files/flightDynamics/flightDynamicsFullVersion.pdf
    At least the flat earth guys can use this science and quote mine the "flat earth", "no spin" earth.

    I would ask a qualified engineer who can do structures like the WTC, like Robertson the chief structural engineer for the WTC, before repeating or accepting nonsense from 9/11 truth. 9/11 truth and flat earth, use the same methods.

    Does the NIST model make invalid assumptions? Engineers make simplifications, and assumptions, which are used to design systems, like the flight systems we all use. The assumption made in your post are not sourced. There is no evidence of fraud.
     
  22. gerrycan

    gerrycan Banned Banned

    Mr John Skilling was the chief structural engineer for the WTC Twin Towers.

    from https://en.wikipedia.org/wiki/John_Skilling


    [1] https://www.britannica.com/biography/John-Skilling


    Robertson is often mistakenly touted as being the lead structural engineer of the WTC, but he wasn't. Also the analysis of the tower impact from a 707 and other fine details or Skilling's input can be read in "City In The Sky" confirming that he was in fact the lead structural engineer on the project.
     
    Last edited by a moderator: Sep 8, 2017
  23. James Ice

    James Ice New Member

    Keith, let's be reasonable here. The question was are the failings of NIST's model accidental or fraudulent. Hulsey addresses this in the short talk and he says they were oversights. But one feels he is being generous.

    If their ommissions were oversights one feels NIST were negligent. You say that aircraft engineers do not use a spherical earth in their models because below mach 3 the effects are insignificant. However, as John85 points out, the effects of NIST's ommissions, e.g. the side plates that prevent the beams sliding off, the stiffeners that would have reduced buckling, the concrete slabs which would have arrested the thermal expansion of the beams - these things are not insignificant.
     
  24. John85

    John85 Member

    Hulsey states that NIST did not include these features in their model during his most recent presentation, at 1:01:50 in the below (no stiffeners, no thermal expansion of concrete deck, no external connections modeled). He also referred to the missing side plates at 38:46. So it's fairly obvious: if NIST did not include these significant, relevant structures in their model, where leaving them out demonstrably changed the prediction of the model from no girder failure to failure, there can only be two options: error, or fraud. Given the sophistication of their study, the time available, the resources and the de facto role NIST has had in 'debunking' conspiracy theories, I am persuaded that these were not error, but fraud. NIST had one job - to cover up the actual cause of collapse and provide legitimacy and a spurious cloak of science to the official story.

    WTC7E.
     
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  25. James Ice

    James Ice New Member

    Yes Jeffrey, but where does this leave you? What if he does in fact address your TTF as closely as he has addressed NIST's Column 79 theory and finds it equally unable to explain the destruction of the building? Do you think you might then feel there was reason to investigate what happened again, or do you think you would find another way to justify thinking there was nothing off about Building 7's demise?

    I suspect the latter. I suspect we have less control over our thinking than we think!
     
  26. John85

    John85 Member

    It may be that engineers can use a flat earth model to test airplanes, because whether the earth is flat or round would have no influence on the model as it predicts flight. However, it does matter whether your WTC 7 column 79 model includes side plates, your girder A2001 model has stiffeners, and whether the shear studs are included.
     
  27. James Ice

    James Ice New Member

    Mick, I agree with you that one requires and education in engineering to understand fully the stuff Hulsey brings up. I think we can see he does make some attempt to explain things to the layman, but we have to admit that a non professional would need some close application of mind to follow his points.

    I think, however, you might be suggesting here that Hulsey is using jargon to fool the non-specialist public into thinking he is making valid points when in reality a specialist would see that Hulsey's points are not valid.

    If you think Hulsey is doing this, do you think he is doing it wittingly?
     
  28. gerrycan

    gerrycan Banned Banned

    ~ (my bolding)
    In support of the side plate point that you make, I would commend to your kind attention this section of a video that was released over 4 years ago, that I think illustrates very well the significance of the C79 side plates.


    I should have added that only the first few seconds of the animated section from 12:03 are specific to the side plate issue.
     
  29. Jeffrey Orling

    Jeffrey Orling Active Member

    My opinion is that these sorts of proofs or what is intended to be a disproof is a fool's errand. Too many unsubstantiated assumptions / variables into am extremely complex dynamic and chaotic situation. Essentially you can prove or disprove whatever you want... because the "researcher" drives the input selection and isolated a node from the entire structure. What NIST apparently did was hardly different.

    The "proof" is that the building collapsed and there were no explosions associated with the release. The best guess is that unfought fires distorted the frame, over stressed connections causing the load paths to be destroyed low down in the building with release beginning in the North East quadrant.

    What was so special about floor 13? Even this seems somewhat arbitrary. Why was floor 11 or 12 modeled? Why not look at the massive transfers which held up a significant part of the tower at the lever just over the sub station in the North East quadrant? This location also was where there was fuel stored as opposed to basic office contents.

    These proofs and disproofs are a waste of time.
     
  30. Oystein

    Oystein Active Member

    You are persuaded by someone who knew the results before the study began, who has broken promises about the study - promises made while soliciting MONEY -, and who has yet to present his actual data and submit his study to actual peer review.

    I think it stands to reason that you are "persuaded" because you want to be persuaded. Nothing in Hulsey's performance to date - and nothing in his CV, neither - contains any indication that we can take his word as gospel.
     
  31. Oystein

    Oystein Active Member

    gerrycan,

    you said elsewhere that Hulsey's study is "superb" - yet this study has not actually been made available, not even a draft. None of the data is avalaible. The public has not been regularly informed on project progress. There seens to be no plan to submit the study to a refereed engineering journal for actual, independent peer-review.

    What makes you so sure the study is "superb" when we actually know nothing about it other than a YouTube video?

    If NIST had presented only a couple of presentations on YouTube - would you praise their study as "superb", too? Why not?
     
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  32. deirdre

    deirdre Moderator Staff Member

    I don't see a side plate on that side.. are there better pictures available? (photo at 14:38 in your video)
    9-8-2017 10-41-31 AM.
    nist-wtc-7-technical-briefing-082608-31-1024.
     
    Last edited by a moderator: Sep 8, 2017
  33. benthamitemetric

    benthamitemetric Active Member

    Except you have zero evidence that the exclusion of those elements was for the purpose of altering the outcome of the study. In fact, this whole comment belies a deep ignorance of the NIST reports and the subsequent comments of their authors as the exclusion of those elements has been discussed ad nauseum for years. Contrary to Hulsey's presentation there is a non-trivial debate as to whether some of those elements (for example shear studs--see item 34 here) were actually incorporated into the building. For others, such as the stiffeners, NIST determined their presence would not have had a material impact on the failure mode they were modeling, and so it was a justifiable simplification.

    What do you think of these simplifications from Hulsey's study?

    1. Did not model the cooling period of the building, despite ARUP demonstrating that floor failure could occur in the cooling period.
    2. Did not model the temperature changes across the building in real time as the fires progressed; instead, only modeled temperature changes in a very small segment of two floors (and it is unclear if they even heated both floors simultaneously, modeled both floors together, or heated them over time from west to east as occurred in reality as the fire progressed).
    3. Did not even model the fires on the floors that Weidlinger Associates claimed initiated the collapse.
    4. In fact, did not even model fires at all and instead apparently just applied maximum temperatures predicted by only one of the fire models made by NIST (and, again, not clear if they did so properly over time or with the proper sequence of movement of the fires from west to east, but their graphics do not indicate that they accounted for any of those things).
    5. Did not account for existing damage to the lower floors in analyzing whether floor collapses would progress.
    6. Did not model the floor deck flutes, even though ARUP determined they could have been a significant contributor to floor failures.
    Are these better or worse than NIST's simplifications? Are they fraud? Why?
     
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  34. Mick West

    Mick West Administrator Staff Member

    I am not suggesting that. If anything it's the opposite. He's trying to make it accessible to people. But there's some things that are simply beyond reach to most ordinary people who have very little understanding of math, physics, or computer simulations.
     
  35. Keith Beachy

    Keith Beachy Active Member

    Who said it matters for the model? How do you know? Prove it.

    Criticizing NIST's work with unfounded claims, will not save a study which decided it was silent explosives from the beginning, a study which ignores it was fire. Nobody needs to use NIST to understand it was the effects of fire. No one has to agree with NIST's probable cause. People can come up with other "probable" causes due the effects of fire, and make changes to building practices to avoid a similar consequences.

    How does making up stuff about NIST's probable cause study help a study to support the fantasy of silent explosives planted by imaginary bad guys? I would not attack a probable study, I would find real evidence for the explosives which leave no blast effects, or thermite which leaves behind zero iron fused to steel. Where does a study find silent explosives and magical no products left behind thermite.
     
  36. John85

    John85 Member

    Hulsey's study demonstrates it. NIST says the girder moves west 6.25 inches with fixed eastern columns, no shear studs, no girder stiffeners, no side plates and no composite, thermally expanding concrete deck. Hulsey's model shows that when all these features are corrected, the expanding beams actually go in the other direction - east - and do not push the girder off its seat.

    Hulsey has not claimed that explosives were used.

    [off topic material removed]
     
    Last edited by a moderator: Sep 8, 2017
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  37. Mick West

    Mick West Administrator Staff Member

    Please restrict discussion to the AE911/Hulsey study/presentation.

    Endless threads recycling every aspect of 9/11 are discouraged. If there's something specific, then start a new thread.
     
  38. John85

    John85 Member

    No, I actually ridiculed 9/11 conspiracy theories whenever I came across them for 15 years or so from Sept 2001.
     
  39. John85

    John85 Member

    There is a 'debate' over the existence of shear studs and value of stiffeners - for the sake of argument, let's say there is. Is fixing the eastern supports justifiable in any way? The fixing of the east supports forced all thermal expansion to happen to the west, in the direction of column 79.

    Hulsey's study is primarily an evaluation of the NIST account of collapse, so it will not go into detail on the ARUP or Weidlinger Associates' models. That said, one of the brief slides in his recent 6 Sept presentation was about the Weidlinger Associates' study, and it will be tangentially addressed in the final report.
     
  40. Oystein

    Oystein Active Member

    But Hulsey has already claimed in the past, and AE911Truth have quoted him on this - and of course Truthers WILL quote him on this,whether or not he repeats this in the final report - that (I paraphrase) "fires could not have brought WTC7 down, 100% certain".

    If Hulsey only did a comment on the finite set of things that NIST looked into, to the exclusion of all other possibilities, some of which squarely on record, many certainly not even fathomed yet, then such a sweeping conclusion must be deemed invalid from the get-go. Agreed?
     
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