WTC 1 & 2. What happened after collapse initiation?

[DC]

Brent Blanchard the CD expert?

 

[JihadJane]

All the steel was forensically examined and catalogued prior to NIST getting it. This is confirmed by Brent Blanchard.

Can you give a supporting reference for this?

I am only aware of material in which Blanchard talks about photographic and video evidence. I would be interested to see other material from him.

I am also ignorant of NIST's role in gathering evidence from the debris which was done a year before the NIST inquiry began.

Thanks.

 

[funk de fino]

Certainly Here you go.

If you have a problem with his claims then please take it up with him and not me.

http://www.jod911.com/WTC%20COLLAPSE%20STUDY%20BBlanchard%208-8-06.pdf

 

[funk de fino]

Brent Blanchard the CD expert?

Him and his team.

 

[GlennB]

...
Nothing can be proved about the Towers' physical behaviour during their apparently explosive disintegration.
...

That's an interesting remark, and a bit of a Trojan Horse perhaps?

What do you mean exactly?

 

[Newtons Bit]

You are assuming that am claiming that the Towers cores comprised of braced frames. I'm not. I was responding to a poster who asserted that all there were no diagonals in the core whereas the photos I posted do show some diagonal bracing. The is nothing in the NIST report that I can find explaining the function of these components.

Diagonals in the vertical direction are called braced frames. They will absorb lateral load even if you don't want them to. And then yield and break.

They are there for construction purposes or that picture is below the 7th floor in which there actually are braced frames.

 

[JihadJane]

That's an interesting remark,["Nothing can be proved about the Towers' physical behaviour during their apparently explosive disintegration."] and a bit of a Trojan Horse perhaps?

What do you mean exactly?

In my comment on page 19 (#760) I quoted NIST President, Dr. William Jeffrey, who said:

“The scarcity of physical evidence that is typically available in place for reconstruction of a disaster led to the following approach:..."

It is interesting that he doesn't explore why there is a scarcity of physical evidence. If sufficient steel had been preserved to reconstruct sections of the Towers then we would have conclusive proof of what happened to them and the world would be spared endless threads like this one! Without this physical evidence there can only be inconclusive hypotheses.

I describe the towers' "collapse" as "apparently explosive disintegration" because it better describes their depicted transformation into very fine dust and broken steel in mid air, much of it hurled horizontally at high speeds.

 

[JihadJane]

WTC evidence destruction

Certainly Here you go.

If you have a problem with his claims then please take it up with him and not me.

http://www.jod911.com/WTC%20COLLAPSE%20STUDY%20BBlanchard%208-8-06.pdf

Many thanks for the link. It is the article with which I was already familiar. Nothing in the article supports your claim that "All the steel was forensically examined and catalogued prior to NIST getting it."

Here is a description of what actually happened to the steel, a lot of which had already been exported before vaguely systematic examination by volunteers began in November:

'WTC Steel Date Collection':

http://911research.wtc7.net/mirrors/guardian2/wtc/WTC_apndxD.htm

 

[JihadJane]

Diagonals in the vertical direction are called braced frames. They will absorb lateral load even if you don't want them to. And then yield and break.

They are there for construction purposes or that picture is below the 7th floor in which there actually are braced frames.

Thanks for the information.

If you have the time and inclination, please indicate on what information you base your assertion that braced frames were only used below the 7th floor? I have been unable to find any information about it.

 

[WildCat]

It is interesting that he doesn't explore why there is a scarcity of physical evidence.

It is stated in the NIST report why there is a scarcity: the steel in the areas of interest no longer had their identifying markings on them. Without those markings it is imopossible to determine where exactly it came from.

I describe the towers' "collapse" as "apparently explosive disintegration" because it better describes their depicted transformation into very fine dust and broken steel in mid air, much of it hurled horizontally at high speeds.

Oh good! Maybe you'll be the first truther ever to calculate how much explosives would be necessary to do what you claim was done. Then explain why there were no audible explosions consistent with such powerful explosives.

Or are you a Judy Wood space beam proponent? Then you just need to calculate the power of said space beam (or DEW if you prefer).

Then maybe you'll see why such an assertion is ridiculous on its face. But truthers run from these questions as if their lives depended on it, I suspect you'll be no different.

So what will it be, will you answer or will you run away?

 

[WildCat]

If you have the time and inclination, please indicate on what information you base your assertion that braced frames were only used below the 7th floor? I have been unable to find any information about it.

It's astounding that a self-proclaimed researcher could be so astonishingly ignorant of the construction of the towers.

But frankly, astounding ignorance is typical of truthers.

 

[funk de fino]

Many thanks for the link. It is the article with which I was already familiar. Nothing in the article supports your claim that "All the steel was forensically examined and catalogued prior to NIST getting it."

Here is a description of what actually happened to the steel, a lot of which had already been exported before vaguely systematic examination by volunteers began in November:

'WTC Steel Date Collection':

http://911research.wtc7.net/mirrors/guardian2/wtc/WTC_apndxD.htm

What part of the answer to assertion 6 did you miss?

"It was then examined and cataloged by a series of forensic investigators, city officials and site managers"

Then "Some time later (the timing varied due to logistical factors) the steel was shipped off site to China"


Are you insinuating that the forensic investigators did not in fact forensically examine the steel?

I sense a goalpost shift coming or an accusation of lies by Brent and his team.

 

[GlennB]

I describe the towers' "collapse" as "apparently explosive disintegration" because it better describes their depicted transformation into very fine dust and broken steel in mid air, much of it hurled horizontally at high speeds.

If you believe that explosives were used at WTC then it would save a lot of dancing and hassle if you'd just come right out and so so, instead of beating about the bush.

 

[R.Mackey]

Diagonals in the vertical direction are called braced frames. They will absorb lateral load even if you don't want them to. And then yield and break.

They are there for construction purposes or that picture is below the 7th floor in which there actually are braced frames.

Point of order, I'm sure you are also aware of the diagonals on the mechanical and lobby floors, also the hat truss, and not just in the core below Floor 7. But the overwhelming majority of floors had no diagonal bracing.

We've gone over this here, what, a thousand times?

 

[Newtons Bit]

Point of order, I'm sure you are also aware of the diagonals on the mechanical and lobby floors, also the hat truss, and not just in the core below Floor 7. But the overwhelming majority of floors had no diagonal bracing.

We've gone over this here, what, a thousand times?

Yes, but in those cases the exterior frame was braced frames The core probably wasn't braced.

 

[cmcaulif]

I use "free fall" only describing the upper block alleged drop or vertical displacement due to alleged simultaneous local failures of the columns prior to "impact" and any destruction of the lower structure.

To clarify I have added a little note in the paper.

thanks, confusion seems to spread quickly without clarity.

However, it doesn't matter if the displacement of the upper block is "free fall" or something else at initiation. As soon as contact takes place, destruction of the upper block would start absorbing strain energy and waste energy as friction. The whole interface between the upper block structure and the lower structure changes ... and you have to analyse that!

Not just say, like NIST, that sufficient energy could not be absorbed due to lack of strain energy in the structure ignoring friction, or, like Bazant and Seffen, that the upper block does not absorb any energy of any kind.

yea, you keep talking about friction, but in order for friction to work well to arrest motion it has to act over a longer time interval than the fraction of seconds these impacts were occurring in.

Consider a car traveling vary fast, the brakes use friction to stop it, but even with the best brakes, the friction force has to act over a noticeable time interval.

Have you actually crunched the numbers on a the magnitude of friction forces?

Evidently the upper block would start to fail at contact and the local destruction of the lower structure would soon be arrested, which I hope you agree to? That's the essential message in my papers.

both will be damaged but the force in each is not equal once the layer of rubble develops between the upper and lower section. Bazant has shown this in the discussion I linked

When this happens, you can determine the force going into the upper block by considering all of the forces on the rubble layer. There is:

Fc corresponding to column resistance in the lower section, acting upward, the magnitude of this is known

Mg corresponding to the mass of rubble layer times acceleration due to gravity, also known using bazants model. Acting downward obviously

Mawhich is the mass of the rubble layer times the average acceleration of the rubble layer. This force must be added in order for the free body diagram to make sense in the accelerating reference frame. This force acts upward since the inertia force always acts opposite to motion. For more see D'alembert's force or D'alembert's principle. This is also known since both values can be calculated using bazant's equations

Fc' finally there is a force of unknown magnitude acting downward(that is, pressing into the rubble layer, see B&V fig 2 for more)

all of these forces have to be in (dynamic) equilibrium, so:

Fc' + Mg - Ma - Fc = 0 (down is positive)
or
Fc' = Fc + M(a-g)

you can note that a will never be greater than g, and will always be less than g by some amount due to column resistance and momentum transfer, so M(a-g) will always be a negative number and Fc' < Fc*

note that as the mass grows, Fc' gets even smaller compared to Fc. Furthermore, a, has been shown to be higher at the beginning of collapse, so as a decreases, Fc' gets smaller as well.

*Bazant takes the algebra one step further and writes Fc' = Fc - M(g -a) to make this more obvious.

 

[Heiwa]

thanks, confusion seems to spread quickly without clarity.



yea, you keep talking about friction, but in order for friction to work well to arrest motion it has to act over a longer time interval than the fraction of seconds these impacts were occurring in.

Consider a car traveling vary fast, the brakes use friction to stop it, but even with the best brakes, the friction force has to act over a noticeable time interval.

Have you actually crunched the numbers on a the magnitude of friction forces?



both will be damaged but the force in each is not equal once the layer of rubble develops between the upper and lower section. Bazant has shown this in the discussion I linked

When this happens, you can determine the force going into the upper block by considering all of the forces on the rubble layer. There is:

Fc corresponding to column resistance in the lower section, acting upward, the magnitude of this is known

Mg corresponding to the mass of rubble layer times acceleration due to gravity, also known using bazants model. Acting downward obviously

Mawhich is the mass of the rubble layer times the average acceleration of the rubble layer. This force must be added in order for the free body diagram to make sense in the accelerating reference frame. This force acts upward since the inertia force always acts opposite to motion. For more see D'alembert's force or D'alembert's principle. This is also known since both values can be calculated using bazant's equations

Fc' finally there is a force of unknown magnitude acting downward(that is, pressing into the rubble layer, see B&V fig 2 for more)

all of these forces have to be in (dynamic) equilibrium, so:

Fc' + Mg - Ma - Fc = 0 (down is positive)
or
Fc' = Fc + M(a-g)

you can note that a will never be greater than g, and will always be less than g by some amount due to column resistance and momentum transfer, so M(a-g) will always be a negative number and Fc' < Fc*

note that as the mass grows, Fc' gets even smaller compared to Fc. Furthermore, a, has been shown to be higher at the beginning of collapse, so as a decreases, Fc' gets smaller as well.

*Bazant takes the algebra one step further and writes Fc' = Fc - M(g -a) to make this more obvious.

Gravity does not produce a rubble layer so it cannot accelerate. Rubble layer is the latest Bazant invention. A bubble! See my article - no rubble layers in any figures. Just locally damaged parts rubbing against each other = friction.

Bazant still ignores friction in all his equations.

Friction starts immediately and is then always active, when two parts are in contact, e.g. brake pads against the brake disc. No rubble is produced - just very small amounts of dust from pads/disc. You are 100% right that the car movement takes some time to be arrested.

Same goes for the WTC1 upper block. But there more and more break pads are activated when parts are locally failing, so the friction increases rapidly.

 

[cmcaulif]

Gravity does not produce a rubble layer so it cannot accelerate. Rubble layer is the latest Bazant invention. A bubble! See my article - no rubble layers in any figures. Just locally damaged parts rubbing against each other = friction.

Bazant still ignores friction in all his equations.

Friction starts immediately and is then always active, when two parts are in contact, e.g. brake pads against the brake disc. No rubble is produced - just very small amounts of dust from pads/disc. You are 100% right that the car movement takes some time to be arrested.

Same goes for the WTC1 upper block. But there more and more break pads are activated when parts are locally failing, so the friction increases rapidly.

When the upper block destroys a section of tower, some fraction of destroyed tower(rubble) remains in the tower while some fraction is ejected causing the observed dust cloud(which is why you can't see a rubble layer, I thought this would be obvious)

This layer is repeatedly compacted as it grows. Note that there are reports of numerous floors compressed into 8 ft IIRC. The meyerowitz photo collection also shows stacked floors. So there is physical evidence of floors impacting each other, which lends support to the notion of rubble layer as the floors pile up.

I really am not sure what you are getting at with the whole friction bit. Forgive me if I have mistaken your meaning, but are you proposing that the debris will behave something like a soil with particle to particle friction being the source of strength?

 

[Heiwa]

When the upper block destroys a section of tower, some fraction of destroyed tower(rubble) remains in the tower while some fraction is ejected causing the observed dust cloud(which is why you can't see a rubble layer, I thought this would be obvious)

This layer is repeatedly compacted as it grows. Note that there are reports of numerous floors compressed into 8 ft IIRC. The meyerowitz photo collection also shows stacked floors. So there is physical evidence of floors impacting each other, which lends support to the notion of rubble layer as the floors pile up.

I really am not sure what you are getting at with the whole friction bit. Forgive me if I have mistaken your meaning, but are you proposing that the debris will behave something like a soil with particle to particle friction being the source of strength?

You have not read my articles. The upper block does not destroy a section of the tower. On all videos it is destroyed before that.

But if the upper block had dropped down and contacted the structure below, the upper block would have been destroyed then, too.

Why? The upper block is not very strong. Being on top it is the lightest and weakest part of the whole tower.

What rubble are you talking about? No rubble is produced when the upper block drops down.

And a layer of rubble? What is below this layer? Something solid? What? A floor?

And what compacts the rubble layer? The upper block? But it has imploded! or it is still intact and its lowest floor compacts?

So how can the rubble layer grow? In thickness?

Rubble is, I understand, bits of broken stone, rock, brickwork, steel pieces, furniture, whatever! Mostly rubbish.

After initiation, was a layer of rubble suddenly produced by the upper block? But how? Where did it come from?

It cannot destroy solid columns of a steel tower. A layer of rubble will just drop by anything as solid as a steel column. No friction, no damages, no global collapse.

Sorry, anybody suggesting that a layer of rubble of increasing thickness destroyed the towers must have a mind of rubbish.

I thought Bazant suggested that it was something really solid and indestructible that crushed down the towers! But now you say it was a layer of rubble!

Rubbish.

 

[pomeroo]

Brent Blanchard the CD expert?

Yes, Brent Blanchard is an expert well respected in the demolition industry.