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

[DGM]

Air resistance is what causes teminal velocity, freefall has no upper limit (unless you want to claim an object in freefall will ever approach light speed). I really think you should learn what your talking about before you look really foolish.

I was referring to the usage of the term as commonly used in this debate (a more lax term). Yes the technical definition of the term excludes everything but gravity.

I'm sorry I ruffled your sensitive feathers.

 

[~enigma~]

I was referring to the usage of the term as commonly used in this debate (a more lax term). Yes the technical definition of the term excludes everything but gravity.

I'm sorry I ruffled your sensitive feathers.

you didn't ruffle anything of mine. You did however argue that physics is wrong and that freefall is determined by gravity plus some other force that you called resistance.

 

[DGM]

you didn't ruffle anything of mine. You did however argue that physics is wrong and that freefall is determined by gravity plus some other force that you called resistance.

I argue the use of the words "free fall" and "speed" being used together. This alone suggests a more lose definition of the term. Strictly speaking you are correct.

Does free fall actually happen in the presence of air? Strictly speaking.

 

[Grizzly Bear]

you didn't ruffle anything of mine. You did however argue that physics is wrong and that freefall is determined by gravity plus some other force that you called resistance.

No, I just think the two of you got confused over what the other was saying. In their respective context you both are generally correct; as free fall is essentially acceleration with no external influences other than the gravity force, and in a vacuum environment it would continually accelerate, where as on earth, the terminal velocity is dependent on the density of the air ( which in the end affects the air resistance) and the mass of the object. (either of you can feel free to correct me if I misunderstood any part of that).

Beyond that the argument truthers keep putting out about free fall as a speed baffles me a bit. In other words I have the same issue as DGM with the words free fall, and speed, used together

 

[beachnut]

As I explained earlier, gravity force alone cannot produce free fall acceleration of a building structural collapse...
...

WTC7 thus drops much too fast to be a CD. So there must be some other force than gravity pulling down the top part (that we see) and removing the bottom structure (that we cannot see) during the destruction.

... What forces/energy caused that?

That's the question. And the answer is quite obvious. Curious? I will enligthen you in my next posting. But a clue! Who or what has the technology to produce the rubble seen in WTC7?

You could keep it a secret and save some point deductions.

Gravity did it, but since fantasy 9/11 truthville ignores gravity, we will have some nut case, fringe, doltish, made up, idea of woo.

What do you call a force from wooville?

 

[~enigma~]

What do you call a force from wooville?

The Grinch aka Jim Carrey

 

[ElMondoHummus]

What do you call a force from wooville?

The Grinch aka Jim Carrey

(*Groan*)

 

[~enigma~]

(*Groan*)
[qimg]http://www.internationalskeptics.com/forums/imagehosting/thum_123864948283fd5b49.jpg[/qimg]

Well it is 9 days before he can steal Xmas in wooville again

 

[Heiwa]

Wait a minute, everyone, wait a minute... Chandler found a limited period of free fall in the 7 World Trade collapse, and it's supposed to suggest explosives? If so, why's the free fall period of time only a portion of the total collapse event? Is the conspiratorial argument that they only demolished part of the building?

Mackey pointed this out earlier, and I've yet to see a satisfactory response: Any small period of free-fall does not automatically mean explosives. At best, it means the portion collapsing was temporarily unsupported. Can someone provide a real explanation for why this period of free-fall is supposed to be significant, and how it supposedly indicates demolitions? Because if the best answer is that the building was supposed to resist collapse progression and no more, then the leap to demolitions is still missing for the reasons it's always been missing: There's no proof that the resistance was eliminated via demolitions or incendiaries. And it doesn't take into account the collapse propogation scenario as described by NIST.

So what is significant about Chandler's find?

The WTC7 structure consists of 24 inner core columns and 26+ outer wall columns supporting 47 floors. NIST suggests that when one inner core column fails (no. 79 between floors 11/13), it produces immediate and simultaneous structural failures - they shear off and displace out of position - of the remaining 49+ columns = total classic collapse!
Thus 24 inner core columns are assumed to penetrate 11-13 floors (we see the top part above dropping) and these floors are piling up = plenty of local failures everywhere (down below that we do not see). It is however incompatible with Chandler's find of free fall. A total classic collapse goes much slower. And also destruction by CD goes much slower. The latter is easy to verify by using Chandler's method studying a CD! At CD the structure never drops with free fall acceleration!
That WTC7 was neither CD or a 'total classic collapse' is also easy to see by looking at the rubble. What produced the big assemblies of junk seen where columns and girders are sheared off everywhere away from very solid connections? Gravity? CD? No! You need much more energy to produce this sort of rubble. It is a pity that NIST cannot explain how these pieces of evidence - the junk - was produced!
NIST maintains that they have a software that can keep track of every failure produced in a 'collapse' (incl. an analysis of the energy/forces required to produce each failure) and then how the various pieces of damaged structure displace until they rest on the ground. NIST however cannot produce any evidence that such software actually exists ... so how could they use it?
So what produced the forces/energy required to produce the junk that enabled the intact structure above to displace at free fall acceleration? It is quite obvious, isn't it?

 

[Heiwa]

I am surprised that Heiwa and a few other earnest scientists here put up with the ridicule and non-scientific attacks and glad handing and circle jerking. But I do enjoy their input and honest attempts at true science. Many others loiter here, reading some of the earnest attempts at truthseeking, with no interest whatsoever in putting up with the dishonest and endless contemptuous mockery.

Thanks! Reason why I discuss at JREF is evidently to test my ideas and get inspiration for improved ideas. Most posters seem quite ignorant so I always try to simplify for easy understanding, e.g. using pizza boxes or bath room scales to illustrate the explanations.
I would love to get hold of the NIST total classic collapse analysis software to use it to analyse my pizza boxes/bath room scales BUT ... it seems not to be commercially available.

 

[Dave Rogers]

So what produced the forces/energy required to produce the junk that enabled the intact structure above to displace at free fall acceleration? It is quite obvious, isn't it?

Yes, it's fairly obvious to me. There was a downward force due to gravity, which Heiwa finally seems to have noticed. There was an upward resistive force due to the structural strength of the facade. For a portion of the fall to be at an acceleration within error bars of 1G, there had to be an additional downward force exerted on the roofline of the building. There was nothing above the roofline that could possibly have exerted this force, so it must have been a tensile force from below; in other words, something was pulling (oops, that word again!) the roof downwards. There is no conceivable way that an explosion at a lower level could exert a tensile force on the structure at rooftop level, and even less so for thermite. However, momentum transfer from some other part of the building that was already falling could exert such a force. Since we know that the core collapse preceded the facade collapse by about 5 seconds, the only rational explanation is that some connection in the structure transferred downward momentum from the already falling core to the facade, which is fully consistent with NIST's finding that the facade collapse was initiated by the core collapse, which in turn propagated outwards from the failure of column 79.

I await Heiwa's bizarre, otherworldly explanation of why the fact that WTC7's collapse behaved totally unlike a CD proves that WTC7's collapse was a CD.

Dave

 

[boloboffin]

NIST suggests that when one inner core column fails (no. 79 between floors 11/13), it produces immediate and simultaneous structural failures...

This is not what the NIST report said. Please check all straw men at the door.

Thus 24 inner core columns are assumed to penetrate 11-13 floors (we see the top part above dropping) and these floors are piling up = plenty of local failures everywhere (down below that we do not see).

Again, this is not what the NIST report said. You have read the NIST report, haven't you? I have. What you're saying here is not what it said.

It is however incompatible with Chandler's find of free fall. A total classic collapse goes much slower. And also destruction by CD goes much slower. The latter is easy to verify by using Chandler's method studying a CD! At CD the structure never drops with free fall acceleration!

For, lo, these many years, we have heard nothing from the CD advocates but that the acceleration of free fall speed meant 7 had to be a controlled demolition. Now you're here telling us that acceleration of free fall speed means it was NOT like a controlled demolition.

Have trouble establishing a coherent theory much?

That WTC7 was neither CD or a 'total classic collapse' is also easy to see by looking at the rubble. What produced the big assemblies of junk seen where columns and girders are sheared off everywhere away from very solid connections? Gravity? CD? No! You need much more energy to produce this sort of rubble. It is a pity that NIST cannot explain how these pieces of evidence - the junk - was produced!

But you can, right? I've a mind to grant you this so I can hear what silly thing has popped into your head to explain it. Woods came up with Directed Energy Weapons to explain the energy deficit she magicked up out of her mind. What's your thing?

NIST maintains that they have a software that can keep track of every failure produced in a 'collapse' (incl. an analysis of the energy/forces required to produce each failure) and then how the various pieces of damaged structure displace until they rest on the ground. NIST however cannot produce any evidence that such software actually exists ... so how could they use it?
So what produced the forces/energy required to produce the junk that enabled the intact structure above to displace at free fall acceleration? It is quite obvious, isn't it?

Go on, say it. NUKES. Go on! Go right on. You know you want to. We all know you want to. Step on up and let that freak flag fly!

 

[Heiwa]

According NIST WTC7 Final Report (20 November 2008) page 90:

"WTC7 was prone to classic progressive collapse in the absence of debris impact and fire-induced damage when a section of Column 79 between Floors 11 and 13 was removed. The collapse sequence demonstrated a vertical and horizontal progression of failure upon removal of the Column 79 section, followed by buckling of exterior columns, which led to the collapse of the entire building."

According NIST removing one piece of column ... POUFF ... the whole structure collapses. I have tried to reproduce this effect by Beam Element Analysis, but ... no collapse. What happens is that the load carried by the column above the removed piece is transmitted to adjacent columns (via the floor girders) where the compressive stress increases from <30% yield to <37% yield. No failures anywhere.

I have described it at http://heiwaco.tripod.com/nist7.htm .

I can go on and remove more pieces of adjacent columns in my BEA model to see how the stresses in the parts increase until failures develp by themselves (connections are ripped apart) but in all cases only local collapse occur above the the modified columns (the floors are locally sagging/dropping down) = vertical progression (as expected).

The failures will not progress horizontally and affect intact columns remote from the local failures (as expected). No way that the whole structure (WTC7) will drop ... free fall ... as demonstrated by Chandler and confirmed by NIST due to some local failures of primary structure in one corner of the structure.

You cannot beat basic BEA!

I still wonder what software NIST is using! A software that can keep track of loose parts flying around! Magic!

 

[Heiwa]

Yes, it's fairly obvious to me. There was a downward force due to gravity, which Heiwa finally seems to have noticed. There was an upward resistive force due to the structural strength of the facade. For a portion of the fall to be at an acceleration within error bars of 1G, there had to be an additional downward force exerted on the roofline of the building. There was nothing above the roofline that could possibly have exerted this force, so it must have been a tensile force from below; in other words, something was pulling (oops, that word again!) the roof downwards. There is no conceivable way that an explosion at a lower level could exert a tensile force on the structure at rooftop level, and even less so for thermite. However, momentum transfer from some other part of the building that was already falling could exert such a force. Since we know that the core collapse preceded the facade collapse by about 5 seconds, the only rational explanation is that some connection in the structure transferred downward momentum from the already falling core to the facade, which is fully consistent with NIST's finding that the facade collapse was initiated by the core collapse, which in turn propagated outwards from the failure of column 79.

I await Heiwa's bizarre, otherworldly explanation of why the fact that WTC7's collapse behaved totally unlike a CD proves that WTC7's collapse was a CD.

Dave

In my opinion there is too little potential energy stored in the building to first produce all the structural failures at floor 12 and second to produce the sudden, vertical displacement at free fall acceleration of the structure above floor 12 as described by NIST (with unknown software).

So you are right - a force of some kind must pull the structure above floor 12 down. This force must not be too strong so that acceleration is more than g or 9.82 m/s² - then it would be too obvious that something is strange - but it would have been smarter to apply a smaller force to produce smaller acceleration.

However, to pull down the intact structure above floor 12 incl. the roof, you must also remove all the obstructions below floor 12, i.e. the intact structure there! Big job! And it must be done just prior the drop of the structure above floor 12 starts.

Easiest is to combine the two tasks, e.g. removing the structure below floor 12 fast that produces an under pressure that assists to pull down the structure above floor 12.

The structure below floor 12 is evidently the strongest of the whole. It carries 35 floors of structure above.

In the rubble you can find big chuncks of below floor 12 structure as described earlier - a core column cut off in two locations above/below a joint where all four attached girders are cut off away from the very strong joint at the column.

To produce such a chunk of scrap there are six strong structural parts that must fail. A normal person evidently ask whether the six failures took place simultaneously (how?) or one after the other (how?). It is not easy to cut six strong columns/girders and produce the chunck seen. And how where the gravity forces applied to the parts to cut them apart?

With NIST magic FEA software it should be easy to answer those questions ... but NIST will not assist.

And if it were not gravity forces that were applied to produce the failures - where did the forces come from?

Just by asking the right questions you will find the answer. Asking NIST for assistance does not help.

 

[Disbelief]

In my opinion there is too little potential energy stored in the building to first produce all the structural failures at floor 12 and second to produce the sudden, vertical displacement at free fall acceleration of the structure above floor 12 as described by NIST (with unknown software).

In your opinion? Aren't you supposed to be an engineer? As such, you should be able to produce calculations for the potential energy to back up your assertion.

And if it were not gravity forces that were applied to produce the failures - where did the forces come from?

Just by asking the right questions you will find the answer. Asking NIST for assistance does not help.

Obviously, it was the new all building vacuum cleaning system that had been installed. When the building was compromised, it went haywire and sucked the building down.

 

[~enigma~]

In your opinion? Aren't you supposed to be an engineer? As such, you should be able to produce claculations for the potential energy to back up your assertion.

Interesting way to say if it sounds like a duck it must be Heiwa.

 

[Disbelief]

Interesting way to say if it sounds like a duck it must be Heiwa.

Thanks for pointing it out. Saying Heiwa sounds like a duck is insulting to ducks the world over.

 

[boloboffin]

According NIST WTC7 Final Report (20 November 2008) page 90:

"WTC7 was prone to classic progressive collapse in the absence of debris impact and fire-induced damage when a section of Column 79 between Floors 11 and 13 was removed. The collapse sequence demonstrated a vertical and horizontal progression of failure upon removal of the Column 79 section, followed by buckling of exterior columns, which led to the collapse of the entire building."

According NIST removing one piece of column ... POUFF ... the whole structure collapses. I have tried to reproduce this effect by Beam Element Analysis, but ... no collapse. What happens is that the load carried by the column above the removed piece is transmitted to adjacent columns (via the floor girders) where the compressive stress increases from <30% yield to <37% yield. No failures anywhere.

I have described it at http://heiwaco.tripod.com/nist7.htm .

That link is one of the biggest pieces of that CD proponents have tried so far to foist on an unsuspecting public.

Let's start off with the first paragraph after the quote from NIST:

WTC7 is a very simple steel structure. There are 24 inner columns supported by external wall columns as per figure right. The columns are primary load carrying parts. The columns are connected by horizontal beams at every floor. The beams are secondary parts carrying local loads to the primary parts. There are 47 floors. Total height of structure is 147 meters.

Björkman provides a helpful diagram of this description. I reproduce it below.

And that's it, that's all we need to know. Every bit of Björkman's analysis is based on this description, which is NOTHING WHATSOEVER like the actual structure of WTC 7. For you to be tripping around the Internet yelling foul at NIST on the basis of an analysis like this is fraud. Aren't you supposed to be an engineer or architect or some such? Can you honestly not tell that this is so completely unlike WTC 7 to be laughable?

For the love of FSM, WTC 7 was a off-center trapezoid. Björkman's model is using a simple rectangle. Björkman also doesn't show where he assumes the internal columns to be, but from In this analysis's cross-section, he has his internal columns equidistant and perfectly symmetrical in his little rectangle. The actual internal columns were displaced to the south and the west to accommodate the WTC access ramp and the Con Edison electrical substation already on site.

In other words, this is a perfect example of the straw man fallacy. Björkman has described a situation utterly unlike Building 7, done his BEA on that fraud, and now proclaims NIST's analysis on the actual structure to be wrong. I honestly cannot believe any building professional with any shred of integrity would promote Björkman's trash. What in the world are you thinking, trotting out such rubbish that even someone like me, a live voice writer and actor, can demolish so handily? Have you no respect for yourself?

 

[Heiwa]

In your opinion? Aren't you supposed to be an engineer? As such, you should be able to produce calculations for the potential energy to back up your assertion.

Of course I am an engineer.

Re calculations I note that NIST does not provide any in its report. NIST refers to some magic software that does its calculations but cannot even provide the details of the software. Only printouts of parts flying around. And of course colorful pictures of various temperatures inside the structure.

Not very helpful actually.

So where do we go from here?

 

[Heiwa]

That link is one of the biggest pieces of that CD proponents have tried so far to foist on an unsuspecting public.

Let's start off with the first paragraph after the quote from NIST:



Björkman provides a helpful diagram of this description. I reproduce it below.

[qimg]http://i56.photobucket.com/albums/g171/boloboffin2/911/bjorkmanbaloney.jpg[/qimg]

And that's it, that's all we need to know. Every bit of Björkman's analysis is based on this description, which is NOTHING WHATSOEVER like the actual structure of WTC 7. For you to be tripping around the Internet yelling foul at NIST on the basis of an analysis like this is fraud. Aren't you supposed to be an engineer or architect or some such? Can you honestly not tell that this is so completely unlike WTC 7 to be laughable?

For the love of FSM, WTC 7 was a off-center trapezoid. Björkman's model is using a simple rectangle. Björkman also doesn't show where he assumes the internal columns to be, but from In this analysis's cross-section, he has his internal columns equidistant and perfectly symmetrical in his little rectangle. The actual internal columns were displaced to the south and the west to accommodate the WTC access ramp and the Con Edison electrical substation already on site.

In other words, this is a perfect example of the straw man fallacy. Björkman has described a situation utterly unlike Building 7, done his BEA on that fraud, and now proclaims NIST's analysis on the actual structure to be wrong. I honestly cannot believe any building professional with any shred of integrity would promote Björkman's trash. What in the world are you thinking, trotting out such rubbish that even someone like me, a live voice writer and actor, can demolish so handily? Have you no respect for yourself?

Well, WTC7 has 24 core columns like mine and and plenty of columns in the side - mine has only 26. To simplify. But the models are basically similar.

So I remove one column part between floors 11/13. Nothing happens! No parts flying around!

Something wrong with my software? Not really - result is only that load carried by column with removed part is transferred to adjacent columns. You can do the same calculation by hand with a pen and paper. But you should be an engineer. With some basic knowledge of statics.

And, pls, be polite. This is a friendly forum.