1. Hitstirrer

    Hitstirrer Active Member

    Now you are suggesting that normal office fires, that move organically along every 20 minutes or so as the fire load is consumed, can cause heavy structural steel to reach a high enough temperature to cause it to fail catastrophically. You have to know thats wrong. Your previous input here tells me that you know thats wrong. It has never happened before or since - yet did that three times in one day. And don't bring up the 'plane damage' and 'plane fuel' points because you would then be arguing against NIST who discounted those as being the cause of collapse of the three buildings. They said fire and gravity did it.

    However, if the steel was heated to a high enough temperature, as could be caused by a thermitic attack, and then if the attacked area was persuaded by a small concussive charge to move aside then what we saw would match the event. As you say, steel fails under heat, but not from an office desk and a hat-stand burning.
  2. Are you familiar with the Sight and Sound Theater Fire, The Delft University of Technology's Architecture Building Fire, the Madrid's Windsor Building fire, the One Meridian Plaza fire, or the Kader Industrial fire ? These fires al have 1 thing in common Steel Framed structures which collapsed due to fire load.

    Do you dispute the fact that steel begins to lose its load bearing ability at 300-400 degrees ?
    • Like Like x 3
  3. gerrycan

    gerrycan Banned Banned

    I presume you mean degrees C, and at that temp it would still have way more than half of it's tensile strength. So it depends on the load and redundancy factor.
  4. please site your source on structual steel retaining "way more than half" of its tensile strength at 300-400 degrees C.

    J.L. Zeng, K.H. Tan, Z.F. Huang, Primary creep buckling of steel columns in fire, Journal of Constructional Steel Research, Volume 59, Issue 8, August 2003, Pages 951-970, ISSN 0143-974X shows a loss of nearly 70%.

    Do you then challange the claim that NT using a formulation of Iron Oxide was used ?
    • Like Like x 1
  5. gerrycan

    gerrycan Banned Banned

    Let's deal with one thing at a time..
    This from http://www.wpi.edu/Pubs/ETD/Available/etd-042907-214619/unrestricted/LaMalva.pdf

    Link me to this please.
  6. Vec

    Vec New Member

  7. gerrycan

    gerrycan Banned Banned

    Sight and Sound Theater
    Single floor open spaced at the fire. Also, as you can see below, only the roof actually collapsed.

    The Delft University of Technology
    This one kind of speaks for itself.........
    I can't be bothered to go through your whole list to be honest. It is well a worn path, and one that has been thoroughly debunked by many.
  8. gerrycan

    gerrycan Banned Banned

  9. Hitstirrer

    Hitstirrer Active Member

    Buildings are off topic but your comments demand a reply. I am surprised that you mention those buildings in fact. Some are not highrise buildings, some are built of concrete, and some didn't collapse at all. If you are going to quote such things I would suggest that you research first to avoid embarrasment, rather than pass on duff information from other debunking sites.

    Sight/Sound http://www.usfa.fema.gov/downloads/pdf/publications/tr-097.pdf

    A theatre complex of four buildings constructed at differerent times. Issues over fireproofing. Huge auditorium with no supporting columns and a massive span roof system. Certainly not a highrise building.

    Delft Uni http://www.dr.dk/nr/rdonlyres/fecddba8-7428-460d-846f-0c3d424d3a81/2748348/delft_brandrapport.pdf

    A 13 story concrete building re-inforced with mild steel that partially collaped. Hardly a highrise steelframe building.

    Madrid Windsor building http://en.wikipedia.org/wiki/Windsor_Tower_(Madrid)

    Thank you for this one. Check the photograph of it the day after its fire. Errr.

    One Meridian Plaza http://en.wikipedia.org/wiki/One_Meridian_Plaza

    Another concrete and steel building that spectacularly FAILED to collapse and had to be demolished EIGHT years later. Thanks for that one too.

    Kader http://en.wikipedia.org/wiki/Kader_Toy_Factory_fire

    Said to be a shoddy building - poorly designed and built. Zero fireproofing or even extinguishers. Stuffed full of plastic and fabric. Oh - and not highrise either.

    As to your comment about steel loadbearing at ( presumably ) centigrade 300/400 then again you are wrong, but rather than take space up I would suggest that once you have looked at the links above you then research the temperatures where steel failure really becomes a problem and get back to me.
  10. Vec

    Vec New Member

    Here's the PDF.

    Attached Files:

  11. gerrycan

    gerrycan Banned Banned

    Thanks for that.
    @FireOfficer1822 forgive me if I am missing it, but where exactly does it endorse what you are saying?
  12. gerrycan

    gerrycan Banned Banned

    @Vec Do you see it??
  13. Vec

    Vec New Member

    I'm not in any way qualified to do the math, which I think is the relevant part. You'll have to wait for @FireOfficer1822 to qualify and/or explain.
    • Like Like x 1
  14. I understand your sourcing and concur with this model , it does not however factor creep (the time-dependent plastic strain under constant stress and temperature)

    In the case of a building under load creep must be considered especially when discussing lower heat ranges and extended times (remember A36 is typically 2 hour rated) I will be honest my math is not the level to explain the report without explaining the entire report and all functions involved (it has been said that if you dont know it well enough to explain it to a 6 year old...... I conceed this statement) I read another report which will better illustrate my point and will post it when i get home but wanted to make sure you knew i was not ignoring the issue.

    Where steel BEGINS to lose its load bearing ability is well documented and agreed upon, the only contention i see here is where failure becomes a major concern and if that point can be reached by a standard fire load. What percentage of loss do you can be described as "begins to lose its load bearing ability" ?

    Yes that is exactly what i not only suggested but demonstrated with several examples of Heavy Structural Steel failing catastrophically. You chose to redefine the peramiters to only high rise buildings pancaking. I will be happy to provide you further examples of Heavy Structural Steel Failing under a normal fire load if you like. Take a day trip to your local fire department and ask them if they are concerned about steel I beams failing while they are inside a building.

    Sight and Sound:

    sound familiar ?
    • Like Like x 1
  15. Alienentity

    Alienentity Active Member

    Uhm, actually no. It's realworld proof that structural steel can fail due to fire alone. Just because the whole buildings weren't on fire, or didn't collapse, does not 'debunk' the fact the steel failed.
    Sorry, you're just wrong here.

    Also in the case of U of Delft, the fire was not present on every wing of the building, but in the areas with intense fire it did in fact collapse. In the case of the twin towers, and building 7, you had an enormously more significant mass for the burning structure to support. This is where things are very different from the other examples.

    Read the following and you might start to understand the forces at play on the steel:
    In the towers, you had loads being carried by columns which were not engineered to do so. This removed the safety factor, the fires then weakened the steel to failure. You cannot expect a damaged structure to perform like an undamaged one. That's just silly.
    • Like Like x 2
  16. Tony Szamboti

    Tony Szamboti Active Member

    The collapse initiation in WTC 1 occurred on the 98th floor, which was only hit by the starboard wing tip and had no core column damage and only a couple of damaged perimeter columns. The twin tower columns had a very high safety factor against gravity induced collapse (at least 3.00 to 1 for the core and at least 5.00 to 1 for the perimeter) so it is hard to understand how one can conclude that the safety factor was completely removed by heating at the 98th floor to effect a collapse.

    Large sections of steel also take a considerable amount of energy to heat which generally requires a significant time to achieve high temperatures in an office fire environment. Additionally, columns can transfer heat away from the fire zone to cooler area. The NIST fire simulation for WTC 7 shows the columns in WTC 7 never reached temperatures above 300 degrees C (a temperature where structural steel has not yet lost any significant strength) and those fires lasted for a much longer time than did the fires in WTC 1.

    Can you provide any source which shows the temperatures required to remove the safety factor from the columns would have been present on the 98th floor of WTC 1 for a sufficient time to cause the steel to reach those temperatures?
    Last edited: Jan 13, 2014
  17. Alienentity

    Alienentity Active Member

    When you word it that way it can appear your argument makes sense.
    But if you take into account the estimated damage to core columns on other floors, the large fires and the redistributed stresses on remaining columns it isn't hard to understand why the building collapsed.
    But I grant you if you don't want to understand, you won't.

    The fires were very large, the steel spans were long, the heating effects were uneven and likely to undergo thermal expansion which would be completely outside the designed parameters of the building. All bets were off.
    Sure, it's possible the buildings could have survived, but they didn't. It's tragic and upsetting. But tragic fires and collapses have happened many times before, not exactly like these, but not entirely unlike them either.

    You have chosen to sift through the event with very incomplete knowledge of the inner goings-on (nobody really knows, after all) and declare that the buildings couldn't have collapsed due to fire. But you can't know that, and the evidence says your wrong - they did collapse, and fire is the only provable mechanism.

    Put it another way: the fires are a fact, they cannot be denied. Your various alternative theories are not facts, they do not rise to the same level of proof. Without some kind of hard evidence you never get there, and are stuck trying to deny proven facts such as steel failure modes. It's pointless.

    We're talking about the towers, not WTC 7. The failure modes for 7 were different - thermal expansion, which does not require very high temperatures along those long spans.

    Your denial of the idea that steel could be heated to failure is a bit silly when we have many examples of large steel structures failing in fires, like the Kader Toy factory - very quickly. Sure, the building was built like crap, but that's the whole point - the towers were badly damaged and compromised; lots of SFRM was removed from steel, leaving it exposed to fires.

    You can't reasonably eliminate fire as the most likely cause for the collapses. That's still the strongest and most supported hypothesis.
    I'm not saying that it's impossible to bring a building down with explosives, or maybe even incendiaries. But without conclusive evidence for those other possible explanations they remain weaker hypotheses.

    I don't need to, because I don't buy your skew on the failure modes.

    I think you'd learn more by performing an independent FEA which could study the fire damage. If you really wanted to study it, I mean. If you just want to force your hypothesis regardless then you don't need another FEA study. I'm very confident that if this were done competently it would corroborate the NIST conclusion in general if not in all details. That's because I think your hypothesis has very low probability, no matter how strongly you believe it.
    • Like Like x 3
  18. Tony Szamboti

    Tony Szamboti Active Member

    What you are basically saying here is that if you don't get into the details the collapse by impact damage and fire makes sense. However, it is the details which contain the real evidence and are what professionals look for in a crime or accident investigation.

    The collapse in WTC 1 initiated at the 98th floor, which had little aircraft damage, and was at least two stories above most of it. The even and rapid horizontal propagation across the 98th floor is extremely unlikely due to fire. The vertical acceleration through the first story is too rapid for fire weakening to have caused it. We know what the yield strength was, and what the onset load would have been, based on the mass above, and we know the minimum resistance of the columns during buckling. In addition, the lack of deceleration is problematic for a natural progression. These things can be calculated, and when they are they show the present official story cannot be true and that some form of demolition devices were used to cause the collapse.

    The NIST did physical testing on the steel it got from the Twin Towers and, other than 3 pieces out of 236, there was no evidence of temperatures capable of weakening the steel. 98% of the steel had not been heated beyond 250 degrees C, where steel has not yet lost any strength. Isn't that interesting?

    It looks like the aircraft impact and fires were causal ruses for the masses.

    [...] the details say those buildings did not come down due to impact damage and fire.
    Last edited by a moderator: Jan 14, 2014
  19. Jeffrey Orling

    Jeffrey Orling Active Member

    You have to consider that a number columns were destroyed by the plane hit and the weight of the building did not drop down so the FOS was push up because there were fewer columns to carry the same loads. Look at the attached slide to see how this process progresses and consumes the axial capacity.

    My calculations show the FOS (at least at the bottom of the tower) was just over 2. I put together several slides which show how this all might have happened (and likely did).

    If you examine WHERE the damage was in 1wtc you can see why the movement / fracture occurs at the 98 floor or so.

    Attached Files:

    • Like Like x 1
  20. Jeffrey Orling

    Jeffrey Orling Active Member

    I have to disagree with you here. The sagging trusses makes no sense especially with the building movements. The best fit hypothesis is Top Drop where the core lost capacity in the plane strike floors (the columns were 3 stories in height.... When columns were severed the column line above is then hanging from above (the connection to the hat truss). As long as those connections could perform in tension the floors live dead loads of the core were redirected via the hat truss to the facade. However it's likely that those connections could not perform in tension... as hangers... and so the columns above broke loose from the hat truss and dropped.

    This loss of the core was accompanied by all the OOS floors from 99 up dropping as well and this was the threshold ROOSD mass which cascaded through the tower and the rest his history.

    What did it? Mech damage, heat and the fact that the column to column connections could not handle the axial loads IN TENSION.

    Attached Files:

  21. Hitstirrer

    Hitstirrer Active Member

    This is about the first time that I have seen a plausible explanation that fits the observations. Your 'top drop cartoon' describes exactly the only way that ALL of the perimeter walls can be pulled inwards simultaneously, and match videos. It also explains the first movement seen in #1 where the antenna drops slightly before any inward wall pulling is seen at the collapse zone interface.. The hat truss was never designed to be a load carrier. Its role was to tie the core and outer perimeter together and transfer loads in lateral directions.

    I also agree with you that the 'sagging truss' theory makes no sense and a central core fall is the only explanation for the same reason.

    Your assumption that severed core columns could fail at their upper connections with the hat truss is sound, as they were not designed to be in tension. The flaw in your scenario is that not all of the core columns were severed, and as such most of the uncut ones would still be supporting the hat truss, albeit after a re-distribution of forces in that area. Also, the undamaged core columns were braced to the cut ones and again a re-distribution of downward force would take place, reducing the tension load on their upper connections.

    To make your excellent cartoon work, all of the core columns have to fall at the same time. As not all were severed that can't happen. Similarly, not all of the core column to hat truss connections can be in tension and fail simultaneously either. That returns us to the possibility that something else caused the entire inner core system to pull their tensioned hat truss connections away simultaneously, drop as observed and with all, or most, of the trusses still in place then all of the perimeter trees would be pulled inwards and downwards, as observed and shown in your cartoon pics.

    You see my problem. You have described exactly what I think happened. But your scenario requires ALL of the core columns to be swinging free simultaneously. The symmetry is the mystery. I think that you can see that yourself because your 'top drop cartoon' shows that.

    From there its a very short step to wonder how all of the core columns can be persuaded to match your requirements.
  22. Mick West

    Mick West Administrator Staff Member

    Wasn't it designed to also carry the antenna? I thought that was a fairly significant part. I heard originally both buildings were planned to have antennas.

    Drifting a bit OT here though.
  23. Hitstirrer

    Hitstirrer Active Member

    As you say, drifting a bit. Still vaguely fire/steel related though.

    Yes, the antenna was substantial, and the hat truss would be specced to carry that. But the discussion was about a 'hanging load' from the entire core column system down to impact point that @Jeffrey Orling correctly identified would be far in excess of its design load. That 'hanging load' would be what was out of spec for the hat truss and its core connections.
  24. Alienentity

    Alienentity Active Member

    No, that's wrong. I'm saying that nobody knows exactly what occurred, so the details of the internal processes are a form of guesswork. Because of this, failing another comprehensive FEA to study alternative mechanisms we need to keep sight of the big picture, which is that there were very large fires coupled with structural damage. Those remain the factual and overriding factors for the collapse.

    That's sheer speculation. It is not fact.

    This is way outside the topic of this thread so I won't touch it.

    No, it just shows that your approach to the fire-induced collapse is flawed and you do not understand what happened. You're inserting a completely untested hypothesis as a certainty, which you shouldn't do.
    If you were to base your conclusions on an independent FEA you might have something, but arguments from incredulity are not proof of any kind.

    It's interesting that you've ignored the fact that at those temperatures empirical tests show that steel can fail at a load of 50- 75% of cold strength.

    If you were being reasonable in your approach you would have to accept that those conditions appear to have been met within both towers. Besides there were many examples of steel columns being bent severely and otherwise mangled. Nobody in their right mind suggests that explosives or incendiaries were responsible for this.

    If these failures occurred in any other building we wouldn't be discussing controlled demolition. The only reason we are is because of the emotional nature of this tragedy and the overwhelming need of some people to see another conspiracy where there is no evidence of one.

    That's probably one of the least scientific observations you've made. I've seen how you evade probabilities you don't favour, from minimizing the exit hole, debris ejection (I think you even denied that anything from flight 11 made it out the other side of WTC 1!). You seem to have developed such a monumental bias against any concept that doesn't involve a special conspiracy.

    There have already been many steel failure examples shown in this thread. If there were videos of them there would not necessarily be absolute certainty about every aspect of the failures; such perfect knowledge in disasters is very hard to come by. We know steel will fail in fire conditions, that is not in question. We know the towers were compromised structurally, but we don't know exactly to what extent this was. And we probably will never know, so there will always be uncertainty in the exact mechanism of collapse.

    The fire-induced failure is still the strongest hypothesis as it is based on the most directly observable facts.

    In the case of the CD hypothesis, it has to be inferred without a primary observation of its existence, unlike the fire hypothesis. So it is even less likely to be correct, or is even less probable, given the overall conditions.
    • Like Like x 2
  25. Jeffrey Orling

    Jeffrey Orling Active Member

    Yes and no.

    The antenna was 360 ton load which was over 3 three core columns with the least capacity and it was also over car 55's shaft which went the full ht of the building. Made no sense to beef up the three column for 110 stories... as it would reduce the size of the freight car shaft so much as to make it useless. This columns around car 55 shaft carried so few floor loads inside the core... basically there to frame the shaft! To deal with the wind loads on the antenna and the axial load the antenna needed to have a wide plate to provide stiffness at its base. The antenna was not guyed or stayed. This end plate support for the antenna was done with the hat truss which had diagonals which are very stiff (triangles don't deform easily! The diagonals moved the antenna loads to several surrounding core columns. You can get an idea of this "strategy" in the attached slides which show the hat truss members in plan and one elevation view.

    Both buildings were designed to have antenna. I don't believe that the hat truss would have been done as it was if there was no antenna

    Attached Files:

    Last edited: Jan 14, 2014
  26. Jeffrey Orling

    Jeffrey Orling Active Member

    Thank you for acknowledging that this hypothesis is a better fit to the building movements.

    To address you point that all core columns would have to fail simultaneously... I would say YES that would work for sure. But they did not have to ALL fail and ALL simultaneously. That is where you are mistaken.

    Also the collapse was NOT symmetrical there WAS tilt... not a lot but enough to indicate that one side failed before the other and hence the tilt.

    What was happening was that the compression to tension support was increasing over the 1.5 hrs the fires acted. There was likely column detachment from the hat truss as soon as columns were severed. The column line above the several column could not hang in tension. At first with most of the core above the plane zone still intact there was LOAD redistribution.. the weight of the column and the floor area framed into it.. was redistributed through the slab and the braces laterally. This was fine as long as the additional load remained below the column's capacity.

    But that was slowly (or rapidly) changing. Heat was eroding capacity. The frame was warping from heading expanding braces in the core. Local floor collapses were occurring in the core. This prevented effective load redistribution and the column was in tension. It broke free... dropping like a sink hole... and this began to spread through the core.. slowly (or rapidly) hollowing it out. Id connected to the hat truss... the columns in tension had their loads redistributed by the hat truss. If not the dropped and the hat truss lost support for its' bottom. Although the hat truss was like a truss bridge it was not designed to span from wall to wall and it depended on the columns of the core to support it.; As they dropped off from failed connections in tension... the hat truss was under stresses it was not designed for and began to sag in in the middle.

    The shit hit the fan when some of the center hat truss members failed and the antenna had no support. This was the final moments when the OOS floors had ONLY facade column support. Obviously the load on the facade was too great. the core was gone unable to carry the OOS floor load and the whole top came down. NB that there were more columns in the hat truss region... more than on a typical floor. This linked the beefed up slabs of the 3 upper mech floor with the 3D hat truss and enabled it to act somewhat as a composite.

    Admittedly this is almost impossible to explain in 2D sketches. Perhaps a crude FEA can simulate this. I don't have the skill to do that. I can only conceive of how this happened.

    And I believe this or something similar explains how the tops can down as they did in both cases.

    Attached Files:

    Last edited: Jan 14, 2014
  27. Alienentity

    Alienentity Active Member

    In the case of WTC 5, there was extensive internal failure of steel due to fire. An FEA analysis was able to model some of the effects seen on recovered pieces and provide insight into the modes of failure.
    The study notably mentions that the collapse occurred during the heating phase of the fire, when firefighters would normally be inside the building. Tragically this is exactly what happened in the twin towers, killing hundreds of firefighters and thousands of office workers.
    It states that normally failure occurs in the cooling phase of a fire:
    Additionally, it predicts that the collapse
    So it is entirely possible, while it didn't happen, that the building may also have suffered an almost total collapse as well. Interestingly if this had occurred we might be witnessing the inclusion of WTC 5 into the controlled demolition conspiracy theories as well.
    The fact that, on 9/11, within the WTC complex itself there was a proven, extensive fire-induced collapse strongly supports the fire hypothesis for the other failed buildings. Here we had multiple buildings with multiple but related failure modes of steel.
    A rational approach would be to look for ways to prevent massive failures in future fires. The continued distraction of CD conspiracy theorists does nothing towards this goal. Those who disagree with the NIST's analysis of the tower failures may indeed develop superior models which could explain the failures better. This could actually make future high rise buildings safer, and I would welcome that approach.

    In the case of this study, there is an acknowledgement of current (as of the era of the WTC buildings) weakness of design and recommendations for improvements to such designs in future. This IMO is the proper way forward:

    • Like Like x 3
  28. Mick West

    Mick West Administrator Staff Member

    Regarding load redistribution, I created this simple illustration of the concept, where the collapse of one supporting member leads instantly to the collapse of the rest.
    Tying in with the fire theme, the point being that localized fires can create what looks like a simultaneous failure over the entire floor, giving a much more symmetrical collapse than you might anticipate from asymmetric fires.
    • Like Like x 2
  29. Jeffrey Orling

    Jeffrey Orling Active Member

    This is a perfect analogous example of the process I was describing! Of course the weakening of the core came from columns being severed... not fatal but with the additional loss of capacity from heat you get something like the crushed cans failing almost at once.

    Great find!
  30. Alienentity

    Alienentity Active Member

    To be fair I didn't specify which general NIST conclusions might be corroborated. I actually meant that the fires produced the failures; that's really the takeaway from the NIST reports for me. I completely accept that there are a number of different mechanisms which were at play, and your idea looks like a very good one to explain the failures.

    To me a good scientific approach will build on previous study, correcting errors and refining the understanding. I think your work will help in this regard.
  31. Jeffrey Orling

    Jeffrey Orling Active Member

    As I don't find evidence of CD and therefore the collapse was caused by mech damage.. and fire. Mech damage didn't do it alone both towers survived well after the crash... so that means it was the heat that did it and that heat could cause mech damage incrementally until final collapse. NIST really did an awful job in explain how sagging trusses could do it. It's an epic fail.

    Does it matter? Yes and no. The way the failure progressed post mech damage could have perhaps been mitigated by a different design. The ROOSD process which is one of the components post top drop could DEFINITELY be mitigated with more robust floor systems and drop the long spans in favor or smaller bays and more columns.

    To me Top Drop and ROOSD and RICD demonstrate engineering compromises. So perhaps the towers might not have collapsed as they did... burned out with a mess on the upper floors. I think that is a very likely scenario with a different engineering design.
  32. Mick West

    Mick West Administrator Staff Member

    I didn't find it, I made it. That's my foot :)
    • Like Like x 1
  33. Jeffrey Orling

    Jeffrey Orling Active Member

    I didn't say you found it. I said - great find.. meaning for ME it was a great find. Wonderful that you created it... excellent real world demonstration of a structural system pushed below an FOS 1.
  34. Alienentity

    Alienentity Active Member

    I figured as much. LOL
  35. Alienentity

    Alienentity Active Member

    I think we agree. I used the term 'mechanisms' but that doesn't mean mechanical damage alone.
  36. Pete Tar

    Pete Tar Moderator Staff Member

    Giant japanese robots? I knew it.
    • Like Like x 1
  37. Jeffrey Orling

    Jeffrey Orling Active Member

    And this analysis kinda leads to the question... why didn't NIST come up with a more plausible model and call a spade a spade... the designs aided in the collapse. This is MY meme and it applies to 7wtc where I have the same take away from my TTF analysis... different structure would not have collapse like a cheap card table. Another NIST epic fail

    Why? How was that possible?
  38. Hitstirrer

    Hitstirrer Active Member

    You may not be aware of it but legal moves are beginning, to demand that the NIST re-visits their various reports and correct anomolies such as you refer to.

    Here is a pdf of a letter from an Attorney to open that process.

  39. Mick West

    Mick West Administrator Staff Member

  40. Tony Szamboti

    Tony Szamboti Active Member

    This is not what would have happened to 47 core columns on the 98th floor to cause them to be perceived to fail simultaneously. All three cans already exhibit local buckling as soon as your weight was applied. Who was it that recently was talking about something from "some guy on the Internet". Oh, that was Mick. Nice try though.