9/11 was an inside job

[Neddy Bate]

And if the structure had weak or easily sheared connection points I'd expect it to be somewhat similar.

That's a pretty a far-fetched analogy. Even if they had built the wooden model with double-sided tape connections, it probably would have collapsed in a totally different fashion. One could even set the top half on fire, and yet much of the bottom half would still remain double-sided taped together.

One thing people don't understand is the kinetic energy involved is enormous compared to the fracture energy of the elements. Neither the connection points nor the beams/columns themselves put up a meaningful fight against an already collapsing building.

Well there must be some reason they constructed the building with actual connections between the beams/columns. If the connections were helpless to assist in the fight to keep the building intact, they would not have bothered to connect them.

 

[Russ_Watters]

Well there must be some reason they constructed the building with actual connections between the beams/columns. If the connections were helpless to assist in the fight to keep the building intact, they would not have bothered to connect them.

You misunderstand: The structure of a building is there to keep it from falling. But once a building starts falling, it isn't designed to stop the fall.

Edit:
Try a little experiment: get a friend to evenly hold a tissue (2ply) flat and taught, by its two sides. Gently place a hammer on it. The tissue should be able to hold it.

Next gently swing the hammer at the tissue. It goes through the tissue as if it isn't even there, with just a little kinetic energy.

 

[Grumpy]

Neddy Bate

That's a pretty a far-fetched analogy. Even if they had built the wooden model with double-sided tape connections, it probably would have collapsed in a totally different fashion. One could even set the top half on fire, and yet much of the bottom half would still remain double-sided taped together.

The columns and panels of the outer frame were connected by bolts. Those bolts had only one function in the beams of the core, to hold the vertical members in alignment. They provided zero strength in carrying vertical loads and would fail if the joint was bent more than a few degrees. In the as built configuration the beams held the vertical loads plus 50%(as a safety factor). The falling debris had more that 2 times that energy after falling only 12 feet(one floor)but the zone of collapse had a failure of three stories of that steel. The remaining building only slowed it down a little once that mass started down.

Grumpy

 

[billvon]

Even if they had built the wooden model with double-sided tape connections, it probably would have collapsed in a totally different fashion.

Would depend on the strength of the tape. That scaling problem again.

One could even set the top half on fire, and yet much of the bottom half would still remain double-sided taped together.

Again depends on the strength of the connections.

If the connections were helpless to assist in the fight to keep the building intact, they would not have bothered to connect them.

The connections were not designed to keep the building intact once it started to collapse. No building is designed that way. They are designed to not collapse in the first place under a set of nominal worst-case conditions - and until 9/11, one of those worst case conditions was being hit by relatively small, slow-moving aircraft.

 

[psikeyhackr]

And again while this was not intended to replicate anything about the WTC, the collapse proceeded almost identically to the sequence depicted in post 985.

https://www.youtube.com/watch?v=NBbz2eIoVDQ

Your comparison is extremely superficial. Steel columns in the WTC were bent out of shape.

Could the structure be rebuilt with the exact same pieces?

If so then none of the kinetic energy which came from the potential energy was used up damaging components. That could not be done with the WTC.

The paper loops in my model sustained damage. They were designed to be as weak as possible relative to their static loads. The wooden pieces in that model were the same all of the way up. My paper loops had to be stronger toward the bottom. My model could not collapse just due to dislocation of the components. The dowel prevented lateral motion but the washers and loops could not have stood without the dowel. They were that weak and unstable. They would have tilted and one side of the paper loop at the bottom would have crumpled.

So if a model does not use up energy damaging its own components in the collapse it is not valid.

psik

 

[Kittamaru]

... and you manage to miss the point yet again... congratulations.

 

[billvon]

Steel columns in the WTC were bent out of shape.

Correct. As I said before, the square/cubed law means that you can't make a physical model 100% accurate. It is considerably closer to reality than yours, but of course neither is close to the actual collapse of the WTC.

The paper loops in my model sustained damage.

Were your paper loops damaged by fire? If not your model is not valid.

So if a model does not use up energy damaging its own components in the collapse it is not valid.

Also correct.

It is amusing that you recently argued that since no model has been built there is some sort of coverup - and now you're arguing that models are not valid. You should really make up your mind.

 

[Neddy Bate]

You misunderstand: The structure of a building is there to keep it from falling. But once a building starts falling, it isn't designed to stop the fall.

Edit:
Try a little experiment: get a friend to evenly hold a tissue (2ply) flat and taught, by its two sides. Gently place a hammer on it. The tissue should be able to hold it.

Next gently swing the hammer at the tissue. It goes through the tissue as if it isn't even there, with just a little kinetic energy.

Hmmm, interesting. I haven't tried it yet, but it seems like that would work. If so, then maybe a model could be built with something like tissues and hammers. I can definitely imagine the hammers crashing through all of the tissues, damaging them as they fall to the floor. However, the first problem would be to build a structure strong enough to hold all the tissues and hammers in a tower configuration. I'm not sure how I'd get the structure itself to disintegrate along with tissues and falling hammers.

Neddy Bate

The columns and panels of the outer frame were connected by bolts. Those bolts had only one function in the beams of the core, to hold the vertical members in alignment. They provided zero strength in carrying vertical loads and would fail if the joint was bent more than a few degrees. In the as built configuration the beams held the vertical loads plus 50%(as a safety factor). The falling debris had more that 2 times that energy after falling only 12 feet(one floor)but the zone of collapse had a failure of three stories of that steel. The remaining building only slowed it down a little once that mass started down.

Let's say that I would like to build a physical model which includes your idea. I set up some model bolts (made of wax, perhaps) which provide "zero strength in carrying vertical loads", but they do "hold the vertical members in alignment." When I melt the wax in the top 1/3 (approx.) of my model, this allows the vertical members to go out of alignment. Sounds promising, but I'm not sure how it helps the top 1/3 demolish the bottom 2/3.

Would depend on the strength of the tape. That scaling problem again.

Again depends on the strength of the connections.

The connections were not designed to keep the building intact once it started to collapse. No building is designed that way. They are designed to not collapse in the first place under a set of nominal worst-case conditions - and until 9/11, one of those worst case conditions was being hit by relatively small, slow-moving aircraft.

Yes, perhaps the scaling problem requires that the strength of the tape should be zero. In that case your video would be a good approximation to a model of the collapse.

 

[psikeyhackr]

Were your paper loops damaged by fire? If not your model is not valid.

Are you saying fire is what caused the destruction of the portion of the north tower more than five stories below where the plane impacted?

Supposedly it is the impact damage and fire which caused the upper portion to fall. But supposedly it was the falling portion which destroyed everything below. But then most people don't want to know the distributions of steel and concrete down the entire building to determine how this was possible.

psik

 

[Grumpy]

psikeyhackr

But then most people don't want to know the distributions of steel and concrete down the entire building to determine how this was possible.

Once again with the lying, can you do nothing but lie? NIST has that information, if you are really interested and not just pushing your idiotic and know-nothing blather.

Grumpy

 

[psikeyhackr]

psikeyhackr

Once again with the lying, can you do nothing but lie? NIST has that information, if you are really interested and not just pushing your idiotic and know-nothing blather.

Grumpy

So why don't you provide the quote and tell everyone which report it is in instead of just CLAIMING it is there?

Here is my quote:

2.4.3 Single Impulse Excitations

Accurate estimation of the tower’s motion during the airplane impact required detailed knowledge of the geometry, weight distribution, and impact velocity of the aircraft, as well as detailed knowledge of the geometry, weight distribution, and structural strength of the tower. At the time of this test series (fall 2003), much of this information was unknown, and the impact motion could only be roughly estimated. To allow this estimate to be made quickly, many simplifying assumptions were made regarding the nature of the impact.

NISTNCSTAR1-5D.pdf page 74

That used to be up on a government site but you may have to download the whole NCSTAR1 report to get it now. But you can still search on text from it and find it on various sites as far back as 2009.

So give us a quote and a source to show us that YOU are not the one lying Grumpy.

psik

 

[Russ_Watters]

Did you find the drawings you asked me about yet, psikeyhackr?

 

[billvon]

Are you saying fire is what caused the destruction of the portion of the north tower more than five stories below where the plane impacted?

Fire was indeed ONE of the things that caused the tower to collapse. But then most truthers don't really want to understand this; understanding would damage their worldview.

 

[psikeyhackr]

Did you find the drawings you asked me about yet, psikeyhackr?

Are you talking about the SAP2000 simulation I already mentioned? I have heard about the simulation a number of times but I have not seen pictures or animations generated from it.

You brought it up so you provide supporting evidence.

psik

 

[psikeyhackr]

Fire was indeed ONE of the things that caused the tower to collapse. But then most truthers don't really want to understand this; understanding would damage their worldview.

Fire may have been involved in initiating the collapse of the north tower but it could not make the falling top portion destroy the lower portion that was untouched by fire. So you can talk vague bullshit implying what you cannot explain. I am impressed.

psik

 

[Kittamaru]

Fire may have been involved in initiating the collapse of the north tower but it could not make the falling top portion destroy the lower portion that was untouched by fire. So you can talk vague bullshit implying what you cannot explain. I am impressed.

psik

You really are daft...

Fire damaged the area the fire was in, weakening it.
The portion of the build ABOVE the fire fell.
It fell ONTO the portion BELOW the fire.
The kinetic energy of this set in motion a chain of collapses that the rest of the building was not DESIGNED nor CAPABLE of stopping.

I really don't understand what your major malfunction is with this... it's pretty self explanatory

here's a question for you... if you were to build a structure out of, say, angel hair pasta that could JUST support up a 16 ounce weight. Now, place the 16 ounce weight on it - it holds, right?

Now, if you take that 16 ounce weight, and drop it from, say, three feet, it would likely punch thru the structure and cause extensive damage, if not destroy it.

Obviously not a direct comparison, but the point is made - kinetic energy is a bitch, where as potential energy is easy to compensate for.

 

[leopold]

Fire may have been involved in initiating the collapse of the north tower but it could not make the falling top portion destroy the lower portion that was untouched by fire.

apparently you don't understand catastrophic failures.
you are also apparently assuming the structure solidly designed and built.

can you explain what happens when lap joints are replaced with butt joints?

 

[Russ_Watters]

Are you talking about the SAP2000 simulation I already mentioned? I have heard about the simulation a number of times but I have not seen pictures or animations generated from it.

You brought it up so you provide supporting evidence.

psik

No, I'm talking about the original building design drawings you demanded I show you in post 1031. I never said anything about aSAP2000 model. Are you losing track of your own posts and everyone elses?

 

[billvon]

Fire may have been involved in initiating the collapse of the north tower but it could not make the falling top portion destroy the lower portion that was untouched by fire.

Sure it could. If you disagree, then tell us what load did the falling upper portion place on the lower portion, and was it above or below the design load? (If you understand basic physics, that is.)

 

[psikeyhackr]

Sure it could. If you disagree, then tell us what load did the falling upper portion place on the lower portion, and was it above or below the design load? (If you understand basic physics, that is.)

I already demonstrated the effect in my physical model. That was the point.

Initial contact exceeds the design load. This results in the LEVELs at the top of the stationary portion and the bottom of the falling portion being crushed. But that crushing takes ENERGY, 0.118 joules in the case of my model. So the falling portion progressively slows down. It stops before it gets to the double loops which would require even more energy to collapse. So if we don't know the distribution of steel down the WTC we can't know how the amount of energy required to produce collapse would increase.

And why can't you or anyone else build a physical model that can completely collapse while damaging its own support components?

psik