Merged David Chandler (ae911) sez "WTC7 was in free fall part of the time"

[Heiwa]

Heiwa, this is your second chance. Provide the quote from the NIST report that I asked you to provide. You've already demonstrated that you're a liar in this thread. If you continue to evade your responsibility to back up your claim or at least forswear the false claim you made, we'll know that you're a coward as well.

NIST has agreed/confirmed the finding of Chandler that the upper part of WTC7 free falls (acceleration 9.82 m/s²) for 2.25 seconds, i.e. there is no support/resistance of the upper part when it displaces downward abt 50 metres. NIST also suggests that this free fall displacement was initiated by failure of column 79 between floors 11/13 followed by a vertical and horizontal progression of failures (no details of course) that apparently removed all support/resistance of the upper part for 50 metres vertically and the complete structure horizontally.

In my Comments to NIST (conveniently ignored) I suggested that NIST should describe the path(es) of failures, i.e. the vertical and horizontal progression of failures, to produce this amazing result - free fall.

NIST apparently has a software that can calculate all failures and the local displacements of failed parts in this path or, more exactly, pathes of failures and what happens to the intact, visible part above (that is seen free falling).

The failures can only be produced by the (potential) energy stored in the structure due to gravity. The NIST software apparently keeps track of that, too, otherwise it cannot complete the analysis. The analysis evidently must be re-done after each failure as the structure and loading change at every step on the pathes of failures.

Any idea what software NIST used? Or is the story of this software just an invention? During my 40 years in structural design I have never heard of any such software, you see!

 

[~enigma~]

During my 40 years in structural design I have never heard of any such software, you see!

That explains the problem quite nicely....SENILITY.

 

[boloboffin]

NIST has agreed/confirmed the finding of Chandler that the upper part of WTC7 free falls (acceleration 9.82 m/s²) for 2.25 seconds, i.e. there is no support/resistance of the upper part when it displaces downward abt 50 metres. NIST also suggests that this free fall displacement was initiated by failure of column 79 between floors 11/13 followed by a vertical and horizontal progression of failures (no details of course) that apparently removed all support/resistance of the upper part for 50 metres vertically and the complete structure horizontally.

How many times do you have to be told this?

THE EXPERIMENT OF REMOVING A SECTION OF 79 FROM 11/13 IS NOT, REPEAT, NOT, REPEAT, NOT, PART OF THE ACTUAL EXPLANATION.

If you continue to mishmash the two together, you demonstrate either your inability to understand plain English or your dedication to spreading a lie. Neither is very complimentary to your character.

The experiment about removing a section of 79 from Floors 11/13 is ONLY meant to demonstrate the structural predisposition to progressive collapse. The ACTUAL explanation involves 79 failing when several floors of support are removed following a localized collapse around that column. That explanation is done with all known fire and structural damage added to the model.

The 11/13 experiment is done with no fire or structural damage whatsoever. The 11/13 experiment makes no mention whatsoever of free fall acceleration attainment. THIS IS YOUR MISTAKE, AMONG MANY OTHERS YOU MAKE.

Quit spreading false information about this event.

 

[stateofgrace]

Yes - I sometimes describe a force in tonnes just for easy feeling and when it will not be misunderstood. Any ideas what software NIST used to simulate the collapse? Dynamic collapse analysis - pretty complex! Plenty of falling parts at various accelerations and new interfaces developing in many places. And what computer was used to handle all data?

Any idea why NIST would ignore an "engineer" that does not understand the difference between mass and weight?

Anyway idea why nobody is paying the slightest bit of attention to you?

No idea?

Of course you don’t.

 

[Heiwa]

How many times do you have to be told this?

THE EXPERIMENT OF REMOVING A SECTION OF 79 FROM 11/13 IS NOT, REPEAT, NOT, REPEAT, NOT, PART OF THE ACTUAL EXPLANATION.

If you continue to mishmash the two together, you demonstrate either your inability to understand plain English or your dedication to spreading a lie. Neither is very complimentary to your character.

The experiment about removing a section of 79 from Floors 11/13 is ONLY meant to demonstrate the structural predisposition to progressive collapse. The ACTUAL explanation involves 79 failing when several floors of support are removed following a localized collapse around that column. That explanation is done with all known fire and structural damage added to the model.

The 11/13 experiment is done with no fire or structural damage whatsoever. The 11/13 experiment makes no mention whatsoever of free fall acceleration attainment. THIS IS YOUR MISTAKE, AMONG MANY OTHERS YOU MAKE.

Quit spreading false information about this event.

Well, according NIST Final report pp 47-48:

“The probable collapse sequence that caused the global collapse of WTC 7 was initiated by the buckling of Column 79 … The buckling of Column 79 led to a vertical progression of floor failures up to the east penthouse and to the buckling of Columns 80 and 81. An east to west horizontal progression of interior column buckling followed due to loss of lateral support to adjacent columns, forces exerted by falling debris, and load redistribution from other buckled columns. … Global collapse occurred as the entire building above the buckled region moved downward as a single unit.”

So, column 79 is damaged, columns 80 and 81 buckle, then all interior columns buckle, other (wall!) columns buckle, global collapse occurs and the entire building above the buckled region (i.e. the whole floor area) moves downward at free fall. No calculations are of course provided.

Furthermore, figures 13.10-13 of the same report show completely different failures (apart from loose parts flying around); e.g. no single unit moving down!

When I do a simple FEA of a similar structure (using N as force, kg as mass, Pa as pressure, m as length, etc, of course) I do not get the same result. I can remove plenty of columns ... and nothing really happens at all, as explained in previous posts. I simply do not believe the NIST structural analysis and the figures. Quite obvious fakes to me! Cannot understand how any US structural engineer accepts the rubbish produced by NIST.

Pity you cannot copy/paste from the NIST report.

 

[boloboffin]

Well, according NIST Final report pp 47-48:

“The probable collapse sequence that caused the global collapse of WTC 7 was initiated by the buckling of Column 79 … The buckling of Column 79 led to a vertical progression of floor failures up to the east penthouse and to the buckling of Columns 80 and 81. An east to west horizontal progression of interior column buckling followed due to loss of lateral support to adjacent columns, forces exerted by falling debris, and load redistribution from other buckled columns. … Global collapse occurred as the entire building above the buckled region moved downward as a single unit.”

At this point, I have to believe you are doing this on purpose, so this will be my last message to you, troll.

Yes, you have quoted the probable collapse sequence, which should not be conflated by you with the 11/13 removal experiment that you keep yammering on about. You have not YET provided a quote from that experiment which talks about free fall acceleration even though I provided you with the section number and pages, both actual and pdf, for you to find this experiment discussed by NIST.

Do you understand, troll? What you have quoted is NOT the 11/13 removal experiment. It is the actual probable collapse hypothesis.

So, column 79 is damaged, columns 80 and 81 buckle, then all interior columns buckle, other (wall!) columns buckle, global collapse occurs and the entire building above the buckled region (i.e. the whole floor area) moves downward at free fall. No calculations are of course provided.

Lying troll. The reasons why with examples from their calculations are indeed given in the final report's main text and the accompanying appendices in two volumes.

Yes, all of THAT is the probable explanation. It is NOT the 11/13 experiment. Do you understand that?

Furthermore, figures 13.10-13 of the same report show completely different failures (apart from loose parts flying around); e.g. no single unit moving down!

There are no figures 13.10-13 in the NIST Final Report on Building 7. There is no Chapter 13 in the main report, within which Figures 13.10-13 could appear. Chapter 13 in the appendix (a detailed description of the probable collapse sequence) has no figures or tables whatsoever, neither in the draft or final version.

Perhaps what you mean is figures 3.10-13 in the main report. In those four figures, there are different failures indicated because the probable collapse sequence is being illustrated at different points in time. This should have been evident to you when the captions gave the times of .5, 2.5, 4.5, and 6.5 seconds respectively.

The last one you apparently cite (3-13) shows (at 6.5 seconds) shows the point at which all interior columns failed. One second later, the perimeter columns were buckling. This is illustrated on the figure you conveniently leave out of your erroneous citation, 3-14. It is at THAT point or very soon thereafter that the upper part of the building, the 33 stories above those eight floors of buckling perimeter columns, begins to attain a free fall acceleration.

Therefore, your wringing of hands about this is specious. What you say you are looking for here has not occurred yet in this sequence of figures. It is not until the point of Figure 3-14 that the final plummet of the remaining building begins, the one 9/11 Truth advocates like to play over and over again.

When I do a simple FEA of a similar structure

Liar. The "similar structure" you use is not similar in the slightest. It is a straw man you have constructed, and it bears no more resemblance to WTC 7 than a block of Parmesan cheese. Your continued insistence on referring to this "similar structure" is ample proof of your trollery.

(using N as force, kg as mass, Pa as pressure, m as length, etc, of course) I do not get the same result. I can remove plenty of columns ... and nothing really happens at all, as explained in previous posts.

And as explained to you countless times, see my above statements. You do not get the same result because you are not using a similar structure.

I simply do not believe the NIST structural analysis and the figures. Quite obvious fakes to me! Cannot understand how any US structural engineer accepts the rubbish produced by NIST.

Pity you cannot copy/paste from the NIST report.

There is no need for you to copy and past from the NIST report. If you could learn to cite from it properly, that would be sufficient.

As I said, this is my last message to you, troll. You demonstrate only the ability to twist, distort, bluff, and wheedle. You are quite obviously here only for your own amusement and lack any shred of good faith needed for a serious discussion of this matter.

Goodbye.

ETA: The software used by NIST for their major analyses came from here:

http://www.ansys.com/default.asp

And here:

http://www.lstc.com/lsdyna.htm

Both ANSYS and LS-DYNA are clearly and frequently mentioned in the report. Another example of your lack of good faith.

 

[Heiwa]

At this point, I have to believe you are doing this on purpose, so this will be my last message to you, troll.

Yes, you have quoted the probable collapse sequence, which should not be conflated by you with the 11/13 removal experiment that you keep yammering on about. You have not YET provided a quote from that experiment which talks about free fall acceleration even though I provided you with the section number and pages, both actual and pdf, for you to find this experiment discussed by NIST.

Do you understand, troll? What you have quoted is NOT the 11/13 removal experiment. It is the actual probable collapse hypothesis.



Lying troll. The reasons why with examples from their calculations are indeed given in the final report's main text and the accompanying appendices in two volumes.

Yes, all of THAT is the probable explanation. It is NOT the 11/13 experiment. Do you understand that?



There are no figures 13.10-13 in the NIST Final Report on Building 7. There is no Chapter 13 in the main report, within which Figures 13.10-13 could appear. Chapter 13 in the appendix (a detailed description of the probable collapse sequence) has no figures or tables whatsoever, neither in the draft or final version.

Perhaps what you mean is figures 3.10-13 in the main report. In those four figures, there are different failures indicated because the probable collapse sequence is being illustrated at different points in time. This should have been evident to you when the captions gave the times of .5, 2.5, 4.5, and 6.5 seconds respectively.

The last one you apparently cite (3-13) shows (at 6.5 seconds) shows the point at which all interior columns failed. One second later, the perimeter columns were buckling. This is illustrated on the figure you conveniently leave out of your erroneous citation, 3-14. It is at THAT point or very soon thereafter that the upper part of the building, the 33 stories above those eight floors of buckling perimeter columns, begins to attain a free fall acceleration.

Therefore, your wringing of hands about this is specious. What you say you are looking for here has not occurred yet in this sequence of figures. It is not until the point of Figure 3-14 that the final plummet of the remaining building begins, the one 9/11 Truth advocates like to play over and over again.



Liar. The "similar structure" you use is not similar in the slightest. It is a straw man you have constructed, and it bears no more resemblance to WTC 7 than a block of Parmesan cheese. Your continued insistence on referring to this "similar structure" is ample proof of your trollery.



And as explained to you countless times, see my above statements. You do not get the same result because you are not using a similar structure.



There is no need for you to copy and past from the NIST report. If you could learn to cite from it properly, that would be sufficient.

As I said, this is my last message to you, troll. You demonstrate only the ability to twist, distort, bluff, and wheedle. You are quite obviously here only for your own amusement and lack any shred of good faith needed for a serious discussion of this matter.

Goodbye.

ETA: The software used by NIST for their major analyses came from here:

http://www.ansys.com/default.asp

And here:

http://www.lstc.com/lsdyna.htm

Both ANSYS and LS-DYNA are clearly and frequently mentioned in the report. Another example of your lack of good faith.

Evidently I mean figures 3.10-13. Pity I cannot copy/paste from the report.

And figure 3.15 shows the free fall phase.

Re the software I know NIST refers to LS-DYNA and ANSYS and makes two models (one only of the bottom 16 floors , the latter of the complete structure) and copy/paste result from the first (damaged) model to the other but these are just simple design softwares that cannot do structural damage analysis as suggested in the report with loose parts flying around and alleged debris re-loading the structure continuously.

NIST might haved tried, e.g. divided the structural 'collapse' into say 5000 of 1/1000 seconds intervals and run 5000 static models, each one representing the status of the structure during alleged collapse with failed parts, new loads, etc, uploaded and included in the new model at every stage, but there is no indication that they do it. Too much manual manipulations involved unless you have a clever software to do it ... which I am interested in. And free flying parts??? And re-loading the model with debris ... and a free falling, intact upper part ???? How to handle that?

So the NIST statement on page 57 - "Computer simulations of … the structural collapse can be used to predict a complex degradation and collapse of a building", has no foundation, I am sorry to conclude. The Chandler observation of free fall during the collapse proves it.

 

[Heiwa]

Just to cheer you up I have updated http://heiwaco.tripod.com/nist7.htm with info obtained from this discussion. Thanks to all participants.

Heiwa

 

[tfk]

A lot of rambling to not even answer the question. What was the potential energy in WTC 7? You kind of give the equation though it would be the mass of the building, not the weight, times gravity times height, though you do provide an answer. You can not possibly be an engineer.

Your principle is correct, but the calculation is off.

My apologies if someone has already pointed this out.

The potential energy of any given body (i) is, as you say,
U(i) = m(i)*g*h(i).

For the building, you'd have to do a summation for each of those parts at its individual height. They are not, obviously, at the height of the building.

If one were to assume (incorrectly) that the mass per floor was uniform from the bottom to the top of the building, then the total potential energy would be equal to

U(total) = 0.5 M(total) * g * Height of building.

As you can see, this is 1/2 the potential energy that you described. Which would be equivalent to bringing all the mass to the mid-height (24th floor) of the building.

You can either set up an equation and do the integration.
Or see it by bringing the first floor up & 47th floor down by 23 floors. The potential energy increase in raising the first floor is exactly offset by the potential energy decrease in the 47th.

Continue with the 2nd & 46th, 3rd & 45th, etc. They all end up in the middle.

The real values of the is going to be considerably lower than this value, because the weight is highly biased towards the bottom floors.

Hope this helps.

tk

 

[NobbyNobbs]

Weight (kg) or load (kg) = mass (kg).

Funny, I spent some time teaching my 9th graders that this is in fact not true. It took the slowest of them less than a week to understand it.

How long did it take you you become an engineer?

 

[tfk]

???

.
"???", indeed.

NIST agrees with Chandler that the intact top part of WTC7 free falls as seen on videos, etc.

.
Wrong.

What a shock...

Chandler says that the exterior North Wall falls "at G". He hasn't said a whole bunch that I've seen about the internal collapse process.

Chandler is wrong.

NIST says that ONLY the external walls fall at accelerations that are less than G, but rise for short periods to values that are "approximately equal to G". NIST says that the building as a whole does NOT collapse "from top down", but rather "from inside (column 79 - 81) spreading towards the external walls".

NIST is right. Mostly. They have made a couple of small errors.

NOBODY but you says "the intact top part of WTC7 free falls". This silliness is, no doubt, a bad habit left over from your WTC towers nonsense.

You suggestion is laughable both factually and for its misinterpretation of what others have clearly stated.

My best estimates of the numbers are:
1. the average acceleration between 1.75 seconds & 4.00 seconds is .94G.
2. the peak acceleration between those two times is .99 G.
3. the time after the start of the collapse of the exterior wall that it took to accelerate from zero G's to .98 G is about 2.6 seconds.

I'm prepared to defend those numbers. Why don't you provide your own numbers.

But in NIST:s computer analysis of the collapse - rapid developments of structural failures horizontally and vertically (not really explained very well) - the top structure (floors 14-47) does not free fall! It disintegrates.

.
Wrong. It was explained quite well. In detail appropriate to the audience.

Wrong. The whole top structure does NOT fall as a unit. It fails first near the core columns (79 - 81), and the failure wave moves horizontally outward towards the walls. It takes almost 7 seconds for this wave to reach the outer walls. CLEARLY proving that upper floors of the structure did NOT fall as an intact unit.

Wrong. There is zero "disintegration" shown in any of the computer models. (An observation of all those little pieces falling down in all the simulations would have shown what a ludicrous suggestion this is. Is this your example of a "competent damage analysis"??)

Wrong. The internal structure does NOT fall in free fall. The pieces & parts collide with elements below, and are thereby slowed far below "free fall" acceleration.

Pls read the NIST report before participating in this discussion.

.
Please go out and see if you can purchase a clue before participating in this discussion.


Tom

 

[davidschandler48]

Citation??

However, the crucial point here is that Chandler's results agree EXACTLY with NIST's. Chandler didn't have to do this work at all. He replicates EXACTLY NIST's graph shown in Fig 12-77 on page 603 of NCSTAR 1-9 (Vol 2). This is page 265 of the downloadable pdf file. The slope of the best fit linear curve is "32.196".

Tfk: Please comment on the veracity of this citation. If it is a clerical error, please cite the correct figure, the correct page and the correct document.

--David Chandler

 

[alienentity]

Tfk: Please comment on the veracity of this citation. If it is a clerical error, please cite the correct figure, the correct page and the correct document.

--David Chandler

Oh, hi David. I have a question for you, since you're reading these threads. No, it's not about WTC 7 and the hysterical claim you were making about fraud. It's about your claims about explosive 'squibs' shooting out of the WTC towers as they collapsed.

Have you, even once, consulted with a leading American demolitions expert, before jumping to these conclusions, or did you pull this 'info' out of the truthersphere?

If you did consult with someone notable, would you be kind enough to tell us who it was, and link us to his/her comments or input?

I'm highly skeptical that you know what you're talking about, as you know. You're probably aware that Niels Harrit is using your video to back up his demolition claims, and both of you are going to look awfully stupid if you keep relying on each other's amateur efforts.

Here's a link to Harrit's comments on Danish TV, complete with clips from your video and your 'expert' opinion.

 

[bill smith]

Tfk: Please comment on the veracity of this citation. If it is a clerical error, please cite the correct figure, the correct page and the correct document.

--David Chandler

Welcome to the forum David Chandler.We hope to see a few good debates.

 

[boloboffin]

Welcome to the forum David Chandler.We hope to see a few good debates.

He's been here. We weren't impressed.

 

[bill smith]

He's been here. We weren't impressed.

Well we are further along the road to Rome now so hopefully that will change.

 

[HyJinX]

Well we are further along the road to Rome now so hopefully that will change.

Really? Did you finally find some compelling evidence or something that supports your lil' fantasy?

 

[tfk]

Tfk: Please comment on the veracity of this citation. If it is a clerical error, please cite the correct figure, the correct page and the correct document.

--David Chandler

Howdy David,

My previous comment is misleading. It took me a couple of minutes to figure out what I was trying to say back then.

I read the NIST report with its Fig 12-77 (pg 603 NCSTAR 1-9 Vol 2) before I'd seen your work. This figure is a direct replication of your work, except that (IIRC) they used a point in the middle of the building where you used the SW corner.

The point that I was attempting to make was that, GIVEN THE NIST CURVE, one would not need to do any more analysis in order to calculate the acceleration. NIST noted the slope of the velocity vs. time curve right on their graph. Which, of course, gives you the acceleration.

I was not intending to imply that your work was not original. Or that your work was not done prior to NIST's published curve. Correct me if I am wrong here, but I now understand your work to have been done first, and NIST's curve to have been incorporated into their report as a result. I dumped the preliminary reports once I downloaded the final one.

In my comments, & in real life, I am not particuarly interested in the "who generated it". I'm interested in "what is the info & is it right".

I understand that "who" & priority are significant to all authors. I apologize if I offended you with my comments.

BTW, it would be nice for you to post here. I do think that it is a little odd that you advocate "open communication" and yet don't allow comments on your YouTube pages or your Speak Out pages.

Do you post elsewhere, where someone may ask you some questions about your methodology? If you recall, we exchanged a couple of emails a little over a year ago. At the time, I recommended (perhaps others did, as well) that you swap from a horizontal reference to a vertical reference in order to get rid of aspect ratio and "out of plane" errors.

C'mon back. It'd be refreshing to have someone on the other side of the aisle who understands math & physics. Some of your philosophical allies here need your math skills.

And it is always true that thoughtful, intelligent adversaries are your best friends when the goal is arriving at the truth.

Regards,

Tom

PS. A lot of the questions about your paper would be answered if you'd post an error analysis on your data.

 

[beachnut]

Welcome to the forum David Chandler.We hope to see a few good debates.

He has posted here before (4 times now) and has failed to produce the evidence of his delusional conclusions on 911. A failure at 911 issues as he pushes his paranoid political junk opinions and failed to make a point except he support bat crazy conspiracy theories like you have on 911.

7 years and 10 months, you and Chandler can't figure out 911 or produce evidence to support your moronic delusion.

Who makes the silent explosives that leave no blast effects or noises? How do you guys make up these failed ideas?

 

[davidschandler48]

My previous comment is misleading. It took me a couple of minutes to figure out what I was trying to say back then.

I read the NIST report with its Fig 12-77 (pg 603 NCSTAR 1-9 Vol 2) before I'd seen your work. This figure is a direct replication of your work, except that (IIRC) they used a point in the middle of the building where you used the SW corner.

I still question the Fig., page, and document reference. I downloaded a fresh copy of the document of that exact title and nothing related to freefall is on that page. The table of figures in the front only goes up to 12-69. If the reference you cite is real, please point me to the correct document.

I was not intending to imply that your work was not original. Or that your work was not done prior to NIST's published curve. Correct me if I am wrong here, but I now understand your work to have been done first, and NIST's curve to have been incorporated into their report as a result. I dumped the preliminary reports once I downloaded the final one.

I think it is rather significant that NIST redid their analysis based on my work. Don't you? Their original work was either so shoddy or so fraudulent that letting it stand apparently became untenable. That's how I read it, anyway. I am not concerned with "credit" per se, but I am concerned with getting the record straight. When you say, "Chandler didn't have to do this work at all" the implication of your words, in the original context, was that NIST had already measured what I measured and therefore I was being sloppy in my own research, rehashing the obvious, and making a mountain out of a molehill. This is exactly the way others in the JREF forum and Screw Loose Change have interpreted your words.

I apologize if I offended you with my comments.

You might disabuse your own crowd of their mistaken perceptions based on your words.

BTW, it would be nice for you to post here. I do think that it is a little odd that you advocate "open communication" and yet don't allow comments on your YouTube pages or your Speak Out pages.

Do you post elsewhere, where someone may ask you some questions about your methodology? If you recall, we exchanged a couple of emails a little over a year ago. At the time, I recommended (perhaps others did, as well) that you swap from a horizontal reference to a vertical reference in order to get rid of aspect ratio and "out of plane" errors.

You apparently have my email address. If you want to communicate with me do so directly. I don't recall correspondence with you because I don't know anybody named Tfk.

C'mon back. It'd be refreshing to have someone on the other side of the aisle who understands math & physics. Some of your philosophical allies here need your math skills.

And it is always true that thoughtful, intelligent adversaries are your best friends when the goal is arriving at the truth.

No way. If I make an occasional appearance it is because I have something to say or some record to set straight. I'm responding here to what I perceived as a civil post on your part. However, I don't find it stimulating, entertaining, or even tolerable to subject myself to an environment where verbal abuse is the norm. (Just stand back and read the neighboring posts on this page. Do you guys go home and beat your wives and kids? Is one of you named Troy?) This forum is sick. IMHO the verbal abuse is encouraged by the culture of unaccountable anonymity. You guys are making a mockery of yourselves. I don't know who you think reads your all this spew. As for why I closed the comments on my YouTube videos, the same unaccountable anonymity corrupts the atmosphere in the 9/11-related video comments. I want to provide an emotionally safe environment for thought, and reflection for my viewers. YouTube has a message system where anyone who really wants to talk to me (as opposed to grandstanding in front of the world) can do so.

I do in fact enjoy intellectual sparring with people who hold contrary views, when conducted in an atmosphere of honesty and mutual respect, or at least bare civility. But I'm not sick enough to need the collective approval of this forum.
--David Chandler
(That's who I really am. Who are you???)