RFC: Bazant and Zhou Simple Analysis refuted

[uk_dave]

I believe it was impossible as there would not have been a dynamic load if the initial collapse was due to fire. One would need a huge dynamic load to cause anything close to a progressive collapse. It just wouldn't be there without other influences like explosives or incendiaries.

The subject of this thread explains that Bazant and Zhou do not have the dynamic load they claim.

So you believe there is not the slightest possibility of the collapse being able to proceed based on the failure witnessed? Not a shred of doubt in your mind?

 

[pomeroo]

Baloney Ron. You just said a few posts back that they got all of the steel they needed. Well in the report it is obvious that they felt they didn't.

No, typically, you can't manage to quote accurately from a post that just appeared. I am in no position to decide whether or not NIST had access to all the steel it needed. Mike Newman told me that the agency obtained a sufficient amount of steel to conduct its tests. Unlike most fantasists, I am not an authority on all subjects and I can speak only for myself.

Additionally, they made the same type of statement with regard to perimeter columns also. See NIST NCSTAR 1-3C pages xlv and xlvi.

I think people like you who want to call themselves rationalists when making these types of arguments should consider a new handle. I think something along the lines of gulliblists might do.

I think that after of more than six years of screaming, the fantasy movement should produce a single piece of evidence suggesting the existence of its mathematically-impossible conspiracy--the conspiracy whose goal was to transfer control of both houses of Congress from the Republicans to the Democrats--the conspiracy that somehow "forgot" to make a single one of its hijackers an Afghani or an Iraqi--the conspiracy that orchestrated a preposterous Rube-Goldberg operation on 9/11/01, but couldn't plant WMD in Iraq.

I still haven't found the part where NIST complains about not having enough steel. Do you agree that NIST understated its case?

 

[Tony Szamboti]

Won't work. Most of your blast wave would be along the face of the column not perpendicular. You need to think about the blast wave propagating along the thickness of the charge not radiating out equally in all directions. What you describe would give you a nice black mark on the column and a big noise.

I guess I don't understand what you are saying.

I believe that a wide flat plastic charge, which is tamped, would send most of its explosive force into the column. I am also wondering if the charge could have been placed at the edges of the column as that area would be stiffened by the end plate and transmit most of the force to the welds.

 

[Gravy]

GIANTS WIN!!!

Okay, Tony: you've had enough time to concoct any number of lame, denialist, weasel excuses for your completely contradictory statements, OR to adjust your beliefs to match reality.

Which is it? Go.

 

[beachnut]

I guess I don't understand what you are saying.

I believe that a wide flat plastic charge, which is tamped, would send most of its explosive force into the column. I am also wondering if the charge could have been placed at the edges of the column as that area would be stiffened by the end plate and transmit most of the force to the welds.

Would never see that blast!? Very silent stuff. No real blast effects. realcddeal still is short evidence.

Where are the blasts like this on 9/11?

 

[Heiwa]

Show something specific that NIST got wrong. Show us where the conclusions are contradicted by the data.

From NIST report - NISTNCSTAR1-6D chapter 5.2 - we learn:

"The aircraft impacted the north wall of WTC 1 at 8:46 a.m. … between Floor 93 and Floor 98. … The subsequent fires weakened structural subsystems, including the core columns, floors and exterior walls. The core displaced downward … At 100 min (at 10:28:18), the north, east, and west walls at Floor 98 carried 7 percent, 35 percent and 30 percent more gravity load loads … and the south wall and the core carried about 7 percent and 20 percent less loads, respectively., … At 10.28 a.m., 102 min after the aircraft impact, WTC1 began to collapse. … The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued."

The highlighted items are not proven.

The potential energy in the building only stressed it statically 20-30% of yield. If that energy is released it should fall to the ground!

It has nothing to do with the strain energy that could be absorbed by the structure, which, BTW, is not calculated by NIST!

Evidently a fair amount of any potential energy released = kinetic energy can be absorbed by the structure, if applied to it, and a static condition is re-established after e.g. local collapse of some supporting members= no further collapse.

So there is no evidence that global collapse ensues for the alleged cause and effect.

Above applies to WTC1. NIST suggests a copy/paste cause/effect for WTC2 even if damage there was in another location and size.

NIST suggests that the potential energy of the mass above was released when all columns in the initiation zone simultaneosuly failed. No evidence for that. It is clear from all evidence that the mass above moved when all visible columns below were intact!

It is then assumed that all the potential energy thus released and transformed into kinetic energy then IMPACTED other structure. No evidence for that.

And it is only if there is an IMPACT that strain energy of structure is of interest.

The above error on one page of the NIST report disqualifies the 10 000 other pages.

 

[Heiwa]

This thread went dead after my message #506! So I assume you all agree that the NIST report is wrong.

 

[GregoryUrich]

Anyone remember the opening topic?

I'll give some clues. It's not controlled demolition. It's not any and all errors in NIST. It's not opinions about other members. If you want to talk about these, PLEASE START NEW THREADS.

Here are some new issues related to the OT:

My derivation of Pdyn has a mistake resulting in an incorrectly low overload ratio. I incorrectly applied the 1/2 energy factor to only the potential energy components and not the strain energy.

I accept MT's arguments regarding Bazant's failure mode and initiation being incorrect, but I will deal with them in the introduction and discussion. I do this because the Bazant and Zhou "simple analysis" model and conclusions will most likely be refuted on their own without challenging every assumption.

Newtons Bit's strain energy calculations seem to have an error giving only 1/2 the strain energies. His derivation uses Pi/12 = 30 degrees, but Pi/12 = 15 degress.

I think these two issues will essentially cancel each other out. However, there are other issues regarding strain energies and I know Tony has some comments on this. Maybe we could first try to deal with the strain energies and then I can fix the two known issues and see where we land.

 

[GregoryUrich]

You're assuming a continuous taper to the columns, which wasn't actually the case. The column section changed stepwise at certain floors - I forget which, but AFAIR they were well below 97. There wasn't therefore any difference between the column profiles in the upper and lower blocks in the initial stages. That would suggest simultaneous crush up / crush down as a first approximation. For a better approximation you'd want to look at the boundary conditions for termination of the elastic shock wave at the free upper end of the upper block and the fixed lower end of the lower block; which gives higher reflection? The reflected elastic wave will contribute to the destruction of the structure fairly early on in the process.

...snip

As can be seen at:

http://wtcmodel.wikidot.com/nist-core-column-data

the core columns tapered quite linearly (every three floors) except for the bottom and topmost parts. The absolute weakest part of the core was floors 105-106. There was a transtition at floor 98 to 20-30% weaker columns. The force in the columns of the lowest floor of the upper part is only slightly less than the force applied to the lower part due to the weight of the lowest floor only acting only the lower part. This difference is 1/14 as opposed to the difference in strength which is at least 1/5. Using B&Z's primary assumption, the upper part most likely fails first, sparing the lower part.

I'm open to input regarding reflection, but it needs to be quantified through a reasonable modeling of the foundation including the baseplates and grillages as well as calculating how much energy gets transmitted to the ground. Losses due to damping should also probably be considered.

 

[twinstead]

This thread went dead after my message #506! So I assume you all agree that the NIST report is wrong.

I think you have no idea what an 'error' is, nor do you have any idea why the page you referenced, which in YOUR opinion doesn't have any evidence to support it, does indeed NOT 'invalidate the other 10,000 pages'.

You've already shown yourself incapable, in both expertise AND ideological bias, of investigating where you left your car keys let alone whether the NIST report contains errors or not.

Now, if we can get back to the topic I can continue to read stuff by people who actually know what they are talking about and learn a few things. In the mean time I'll defer to REAL experts to help me understand the NIST report.

 

[SDC]

This thread went dead after my message #506! So I assume you all agree that the NIST report is wrong.

Most of the people posting around here are in North America. In my area (Eastern time zone) you posted 506 at 1:23 am and then proclaimed your glorious victory at 5:41 am.

Hint: most people are asleep at those times. Or in any case, not on line.

 

[bje]

Most of the people posting around here are in North America. In my area (Eastern time zone) you posted 506 at 1:23 am and then proclaimed your glorious victory at 5:41 am.

Hint: most people are asleep at those times. Or in any case, not on line.

You assume Heiwa understands time zones - zones other than twilight zones.

 

[GregoryUrich]

Bump. PLEASE STAY ON TOPIC!

Anyone remember the opening topic?

I'll give some clues. It's not controlled demolition. It's not any and all errors in NIST. It's not opinions about other members. If you want to talk about these, PLEASE START NEW THREADS.

Here are some new issues related to the OT:

My derivation of Pdyn has a mistake resulting in an incorrectly low overload ratio. I incorrectly applied the 1/2 energy factor to only the potential energy components and not the strain energy.

I accept MT's arguments regarding Bazant's failure mode and initiation being incorrect, but I will deal with them in the introduction and discussion. I do this because the Bazant and Zhou "simple analysis" model and conclusions will most likely be refuted on their own without challenging every assumption.

Newtons Bit's strain energy calculations seem to have an error giving only 1/2 the strain energies. His derivation uses Pi/12 = 30 degrees, but Pi/12 = 15 degress.

I think these two issues will essentially cancel each other out. However, there are other issues regarding strain energies and I know Tony has some comments on this. Maybe we could first try to deal with the strain energies and then I can fix the two known issues and see where we land.

 

[Heiwa]

Most of the people posting around here are in North America. In my area (Eastern time zone) you posted 506 at 1:23 am and then proclaimed your glorious victory at 5:41 am.

Hint: most people are asleep at those times. Or in any case, not on line.

Actually I wrote it for US media - never sleeping? - so they could announce it in the local morning news ECT, etc. But they appear to be still sleeping. Sorry for disturbing your sleep. Back to topic. Is the relevant NIST statement about cause and effect - The release of potential energy due to downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse ensued - true? This is one basic assumption of the Gurich paper, that is the topic.

 

[Newtons Bit]

Anyone remember the opening topic?

I'll give some clues. It's not controlled demolition. It's not any and all errors in NIST. It's not opinions about other members. If you want to talk about these, PLEASE START NEW THREADS.

Here are some new issues related to the OT:

My derivation of Pdyn has a mistake resulting in an incorrectly low overload ratio. I incorrectly applied the 1/2 energy factor to only the potential energy components and not the strain energy.

I accept MT's arguments regarding Bazant's failure mode and initiation being incorrect, but I will deal with them in the introduction and discussion. I do this because the Bazant and Zhou "simple analysis" model and conclusions will most likely be refuted on their own without challenging every assumption.

Newtons Bit's strain energy calculations seem to have an error giving only 1/2 the strain energies. His derivation uses Pi/12 = 30 degrees, but Pi/12 = 15 degress.

I think these two issues will essentially cancel each other out. However, there are other issues regarding strain energies and I know Tony has some comments on this. Maybe we could first try to deal with the strain energies and then I can fix the two known issues and see where we land.

Oops. There goes my factor of conservative in favor of collapse prevention. There's also another error in the calculation, in that the degree of rotation of the middle hinge is actually half of the top and bottom hinges, but fixing that one seems more trouble to explain it than to just get a lower number.

 

[WildCat]

Actually I wrote it for US media - never sleeping? - so they could announce it in the local morning news ECT, etc.

 

[GregoryUrich]

Oops. There goes my factor of conservative in favor of collapse prevention. There's also another error in the calculation, in that the degree of rotation of the middle hinge is actually half of the top and bottom hinges, but fixing that one seems more trouble to explain it than to just get a lower number.

Isn't the degree of rotation for the middle hinge twice the top or bottom? That would give us a factor of 4Pi/6 (using 30 deg).

 

[Newtons Bit]

Isn't the degree of rotation for the middle hinge twice the top or bottom? That would give us a factor of 4Pi/6 (using 30 deg).

You measure the rotation from the horizontal. If the top and bottom would be 30 degrees, the middle one would actually rotate 60 degrees, this is true. However you would only use 30 degrees for the strain energy calc of the middle hinge.

It's not going to undergo 30 degrees of rotation.

Ooh Oooh, I could use this to show that I never really had a mistake after all!

 

[Major_Tom]

Myriad asks:

What is the evidentiary basis for doubting their expertise?

Collapse initiation in both buildings is perhaps the most profound engineering question there is.


Millions of follow human beings have sincere questions regarding the suspicious circumstances behind the collapses.


I'd say that any structural engineer worth his salt would want to know what possible design flaws lead to collapse initiation, if any.




Within this context, how is it possible that no photographic record is kept of the core columns from the collapse initiation zone?


Why do you ask that I share your "faith"?

Why not just show me some of these buckled columns?



Possibly the most fascinatiing structural failures ever and we can't photograph the 100 or so pieces of metal that initiated them?



"Mangled" columns are no longer an excuse, for the columns, both core and perimeter, were remarkably well-preserved.



Call me a skeptic.

And 6 years on, you ask why I don't share your faith?

 

[SDC]

MT's comments really come down to, "why didn't they prepare to study the collapse before it happened?" It's time to dance the Time Warp.