Layman's terms please! Tower collapse issue

[tsig]

Thanks for the peep review:

1. The photo of WTC2 shows the upper block inclined outside the lower structure and, logically, cannot drop on the lower structure (it will contine to incline and slide off). In fact it disappears completely soon after.

2. The upper block is supposed to be rigid and intact. It is not supposed to be damage before initiation. My point is that the upper block of WTC1 disintegrates 3-4 seconds before initiation, which is not explained.

3. The upper block of WTC1 is not NEAR free falling on the lower structure below the initiation zone. It telescopes into itself, while the structure in the initiation zone is intact! Just look at the bottom of the upper block - floor 97.

4. No, the static stresses in the load bearing columns prior collapse are >20% yield in the walls and <30% yield in the core. Calculations are given in the paper.

5. Still, the floor is not a primary load bearing part. Clear from the article. It only transmit a load on the floor to the column. Remove all floors and no loads are transmitted to the columns, the latter then only being stressed by their own weight <3% of yield. Buckling is then prevented by the spandrels/beams and the other walls. Service floors are different with strong beams connecting perimeter/core.

6. The columns of the upper block are interconnected with spandrels/beams at every floor that will transmit the load on the cut column to the other columns. Remember that 38 wall columns were cut 100+ minutes earlier and nothing happened.

7. For an upper block to free fall vertically and impact all columns of the structure below simultaneously, evidently all the remaining supports must be removed at the same time. If the upper block tilts or gets inclined because the supports do not fail simultaneusly, the impact cross area of the upper block is also inclined = no instantaeous impact! Compare 1 above.

8. I know the upper block was not lowered. It collapsed into itself before it started the move down into the initiation zone.

9. Reference link is British authorities. At 500°C only yield stress is reduced, say 20%.

10. It is more likely that the energy will slip off the relevant structure (vertical column) and do no harm whatsoever. Read the complete paragraph.

11. No, the floors only there to transmit load on the floor to the columns. Remove the floor (and the load) and the column will still stand (thanks to spandrels and beams - and extra structure at the service floors).

12. You do not know what a gravity driven collapse is, do you?. You need KE for that and it can only be provided by an intact, rigid, uniform density upper block that remains intact, rigid, with uniform density during the whole destruction of the lower structure. The upper block is the only part that can provide KE during the alleged global collapse. The lower structure does not add any extra KE to the collapse or contribute to the collapse - it is being destroyed (lack of strain energy according NIST).

Actually, the upper block, intact, rigid and of uniform at start of collapse, should according to Bazant's and Seffen's theories remain INTACT after the global collapse ... on top of all rubble the upper block has produced of the lower structure. Nothing could destroy a rigid block of uniform density - not even the final impact with the ground forgetting that the rubble is there to dampen the final impact.

But thanks anyway for your input!

Well they weren't virgins anymore.

Oh you said intact I read intacta.

What with rigid blocks blocks impacting with the ground and leaving a damp imprint it was a natural mistake.

 

[Heiwa]

Then quote mining you to prove the opposite of what you said.

I like the quillets. And you know, reputation is an idle and most false imposition, often got without merit and lost without deserving. When Nist speak fustian, hot and moist means anything.

 

[Newtons Bit]

Thanks for the peep review:

1. The photo of WTC2 shows the upper block inclined outside the lower structure and, logically, cannot drop on the lower structure (it will contine to incline and slide off). In fact it disappears completely soon after.

No it doesn't. How hard can it be to use your own eyes when looking at a picture? The upper block has ROTATED, and it cannot slide. For an object to be able to slide off the surface of another, both surfaces must be capable of resisting a force that will move the upper block over. Homogeneous objects can do this (tree trunks, bales of wool). Steel structures cannot. The upper block physically can't slide off the lower block.

2. The upper block is supposed to be rigid and intact. It is not supposed to be damage before initiation. My point is that the upper block of WTC1 disintegrates 3-4 seconds before initiation, which is not explained.

The upper block is NOT supposed to be rigid and intact. It is modeled that way by people like Bazant to make the MATH EASIER. Do you understand this concept, yes or no? That's a direct question, I expect an answer. Furthermore, how can the upper block disintegrate before the collapse even starts? Do you even read what you write?

3. The upper block of WTC1 is not NEAR free falling on the lower structure below the initiation zone. It telescopes into itself, while the structure in the initiation zone is intact! Just look at the bottom of the upper block - floor 97.

I would say, "no it's not" again. But that doesn't have the same affect as me saying, "prove it". You say the lower structure is intact. You can't see this because it's obscured by smoke. Logic suggests that damage done to the upper block must also correspond damage to the lower block.

4. No, the static stresses in the load bearing columns prior collapse are >20% yield in the walls and <30% yield in the core. Calculations are given in the paper.

Complete B.S. Again, you do not provide calculations in your paper. This is your "calculation":

The mass above the core is only13 200 tons supported by the 47 core columns with total area 2.1 m². On average each core column carries abt 280 tons so the average compression is 629 kgs/cm² or 63 MPa or 25% of yield

THIS IS NOT AN ACCEPTABLE MANNER IN WHICH TO CALCULATE INDIVIDUAL STRESSES IN THE COLUMNS. It ignores individual columns being overloaded, it ignores columns being stressed laterally by the structure redistributed vertical forces.

5. Still, the floor is not a primary load bearing part. Clear from the article. It only transmit a load on the floor to the column. Remove all floors and no loads are transmitted to the columns, the latter then only being stressed by their own weight <3% of yield. Buckling is then prevented by the spandrels/beams and the other walls. Service floors are different with strong beams connecting perimeter/core.

Again, complete ********. The spandrels cannot brace the columns in the out-of-plane direction. This is simple engineering mechanics. Please explain to me how a 5/8" over the course of 208ft is going to brace a column against buckling.

6. The columns of the upper block are interconnected with spandrels/beams at every floor that will transmit the load on the cut column to the other columns. Remember that 38 wall columns were cut 100+ minutes earlier and nothing happened.

Then why do you not include the effect of this in your calculations? I have, I found that the columns being cut alone wouldn't cause collapse, but if the other columns nearby where then heated above 600c that they would fail. Why can't you do this? Are p-delta calculations too difficult, or are you afraid of the result?

7. For an upper block to free fall vertically and impact all columns of the structure below simultaneously, evidently all the remaining supports must be removed at the same time. If the upper block tilts or gets inclined because the supports do not fail simultaneusly, the impact cross area of the upper block is also inclined = no instantaeous impact! Compare 1 above.

No, the columns do not fail at the same time. There is a chain reaction from one wall failing due to p-delta affects causing large stress redistribution to the other remaining columns which in turn get pulled over. The fact that these do no fail simultaneously is shown BY HOW THE TOWER ROTATES. THIS HAS ALREADY BEEN EXPLAINED, STOP WITH THE STRAWMAN.

8. I know the upper block was not lowered. It collapsed into itself before it started the move down into the initiation zone.

How the frick can something collapse into itself before it moves down?

9. Reference link is British authorities. At 500°C only yield stress is reduced, say 20%.

A picture is worth a thousand words


I have to wonder why you didn't say 600°C That's more than a 50% reduction. And then of course, there is the modulus of elasticity decreases, which are significant from a p-delta perspective.

And then in your paper, your say:

How is the yield stress of steel affected by heat? In this writer's opinion it is not affected very much at about 500°C. This is confirmed by any fire test - the test chamber and what's in it never collapses due to the heat inside up to 1000°C. The heat inside is normally by kerosene set on fire.

Why do you mention 1000°C tests without mentioning the change in yield stress? Are you trying to confuse the "children" that read your paper?

10. It is more likely that the energy will slip off the relevant structure (vertical column) and do no harm whatsoever. Read the complete paragraph.

STOP DODGING. You confused the terms "rupture" and "buckling" in your paper. If you had experience in the subject you wouldn't do so.

[/quote]11. No, the floors only there to transmit load on the floor to the columns. Remove the floor (and the load) and the column will still stand (thanks to spandrels and beams - and extra structure at the service floors).[/quote]

NO. See my response to 5.

12. You do not know what a gravity driven collapse is, do you?. You need KE for that and it can only be provided by an intact, rigid, uniform density upper block that remains intact, rigid, with uniform density during the whole destruction of the lower structure. The upper block is the only part that can provide KE during the alleged global collapse. The lower structure does not add any extra KE to the collapse or contribute to the collapse - it is being destroyed (lack of strain energy according NIST).

The lower structure does provide additional energy to the collapse, it does this because it is a spring and it compresses. This is simple freshmen physics. Furthermore, as the upper block is damaged, it also falls and adds KE into the mix. Or are you trying to say that a section of column that weighs over 100 pounds per foot can't damage a 4" concrete slab?

Actually, the upper block, intact, rigid and of uniform at start of collapse, should according to Bazant's and Seffen's theories remain INTACT after the global collapse ... on top of all rubble the upper block has produced of the lower structure. Nothing could destroy a rigid block of uniform density - not even the final impact with the ground forgetting that the rubble is there to dampen the final impact.

Stop confusing assumptions made for ease of calculation with reality. No one says the upper block ACTUALLY REMAINS INTACT except you moronic truthers searching for strawmen to validate your religion with.

I'm not some contractor, or a physicist, or a kid in college. I get paid to design buildings. You cannot go toe to toe with me with fake engineering and expect me to not call out your crap.

 

[Heiwa]

Stop confusing assumptions made for ease of calculation with reality. No one says the upper block ACTUALLY REMAINS INTACT except you moronic truthers searching for strawmen to validate your religion with.

I'm not some contractor, or a physicist, or a kid in college. I get paid to design buildings. You cannot go toe to toe with me with fake engineering and expect me to not call out your crap.

The FACT remains that the basic assumption of Bazant, Seffen and Nist is that the upper block remains rigid, has uniform density (0.18 tons/m3) and is intact during ... and after ... the complete global collapse in order to produce and apply the PE/KE required to defom, rip apart and throw out of the way all components in the lower structure down to ground level originally held together by their strain energies, SE.

As no such upper block is seen during ... and after ... the collapse of WTC1 or 2 the theory of Bazant, Seffen and Nist is simply wrong. It is in fact another smoking gun, very easy for everyone to see!

Bazant, Seffen and the Nist engineers are in my opinion a shame for the scientific engineering society producing obscure fantasies in support of political means and ends ... and very few object. Very sad!

I have seen it before, of course! http://heiwaco.tripod.com/ekatastrofkurs.htm

 

[Architect]

Nice posts, NB. I expect more handwaving from Heiwa.

Heiwa. I don't believe you have any structural experience. You ignore or overlook basic aspects of structural analysis in a way that suggests that it is, in fact, you who are the greenhorn.

Incidentally, you never responded to my challenge. I can prove to the Mods that I've won a Civic Trust award for my work on the design of tall buildings. I'll do so on the understanding that, having done so, you ackowledge that I know more about this specialist field than you do.

 

[Dave Rogers]

ETA means ? I'm normally a nitpicker but with things like this you have to read between the lines. I think he means that the top section compacts above the stories that are first expected to fail.

ETA = Edit To Add, I think.

Read between the lines? I think you've defined the truther fallacy in a nutshell. You've decided in advance that Heiwa is reasonable and sane, and therefore when he says something that is unreasonable and insane, you adjust its meaning to correspond to your predetermined conclusion. In the same way, you've decided in advance that 9-11 was an inside job, so when presented with contradictory evidence, you adjust its meaning to circumvent the contradiction. I've seen you having problems with this because you have enough honesty to feel uncomfortable with what you're doing, but so far you've been clever enough to fool yourself.

Read what Heiwa says, not what you want to think he says. Then you'll see it's nonsense. He's not claiming that the collapse started in the wrong place, because he isn't making any comment about where the collapse should have started. He is repeatedly stating that the structure in the initiation zone remained intact while the top section telescoped. That's self-contradictory.

Dave

 

[Architect]

Einsteen

If you look back over Heiwa's posts and the lengthy technical critiques, I suspect that you too will have concerns about his analysis. Do your really agree with him that 30,000t of debris wouldn't weight the same as 30,000t of intact building? Do you really think that it should have slid off the lower part? Do you really think that the building is designed as a "birdcage" when all the facts say otherwise?

I fear that Heiwa is the new ChristopherA.

 

[MRC_Hans]

The FACT remains that the basic assumption of Bazant, Seffen and Nist is that the upper block remains rigid, has uniform density (0.18 tons/m3) and is intact during ... and after ... the complete global collapse in order to produce and apply the PE/KE required to defom, rip apart and throw out of the way all components in the lower structure down to ground level originally held together by their strain energies, SE.

As no such upper block is seen during ... and after ... the collapse of WTC1 or 2 the theory of Bazant, Seffen and Nist is simply wrong. It is in fact another smoking gun, very easy for everyone to see!

Bazant, Seffen and the Nist engineers are in my opinion a shame for the scientific engineering society producing obscure fantasies in support of political means and ends ... and very few object. Very sad!

I have seen it before, of course! http://heiwaco.tripod.com/ekatastrofkurs.htm

I think they will survive. In fact they will conclude that you must be an extremely ignorant person if you try to project the simplifications of a simulation model back to reality.

Perhaps you are unfamiliar with simulation models? Then I can tell you that simplifications like these are the norm, and indeed necessary, if calculations are not to take days, even on a supercomputer.

And since the purpose of this simulation is to calculate the energies involved, such simplifications are really of little consequence for the result.

Hans

 

[Dave Rogers]

Do you really think that it should have slid off the lower part?

That would actually make more sense than what Heiwa is proposing. Einsteen, do you really think that every column of the upper section should have fallen past every column of the lower section, without any contact with it, thereby allowing the upper section of the building to fall without falling off the lower section and also without damaging it in any way? According to Heiwa, this is why a steel-framed building cannot collapse under any circumstances.

Dave

 

[Newtons Bit]

The FACT remains that the basic assumption of Bazant, Seffen and Nist is that the upper block remains rigid, has uniform density (0.18 tons/m3) and is intact during ... and after ... the complete global collapse in order to produce and apply the PE/KE required to defom, rip apart and throw out of the way all components in the lower structure down to ground level originally held together by their strain energies, SE.

As no such upper block is seen during ... and after ... the collapse of WTC1 or 2 the theory of Bazant, Seffen and Nist is simply wrong. It is in fact another smoking gun, very easy for everyone to see!

Bazant, Seffen and the Nist engineers are in my opinion a shame for the scientific engineering society producing obscure fantasies in support of political means and ends ... and very few object. Very sad!

I have seen it before, of course! http://heiwaco.tripod.com/ekatastrofkurs.htm

It's an ASSUMPTION to make the MATH easier, maybe even necessary to make the math possible. This is not what they say happened that day. If you think that assumption is too far from reality to be accurate, then make your own. And no, your "paper" doesn't apply. It's junk and doesn't have any calculations of this magnitude in it.

 

[Architect]

Seconded.

 

[MRC_Hans]

Actually, isn't the solid block assumption in the simulation sort of a worst-case scenario? The way I see it, a solid block of uniform, fairly low, density would be the object least likely to start a global collapse because it would offer the best possible distribution of force to the structure below.

Whereas a jumble of tumbling floors, jagged girder ends, and other stuf could punch through anything.

It would seem that calculations show that even Heiwa's wool-bale would have brought down the building.

Hans

 

[Heiwa]

It's an ASSUMPTION to make the MATH easier, maybe even necessary to make the math possible. This is not what they say happened that day. If you think that assumption is too far from reality to be accurate, then make your own. And no, your "paper" doesn't apply. It's junk and doesn't have any calculations of this magnitude in it.

Exactly! So I propose friendly in my article that named persons/institutions redo the MATH assuming a non-rigid upper block with non-uniform density ... plus considering that the WTC1 upper block was not intact during the collapse. As I describe in my popular article. It is a big difference between an alleged free fall + impact of a rigid body and a non-rigid body. The result is completely different. An impact by a non-rigid body is by definition not an impact to start with.

Evidently a 33 000 tons rigid or non-rigid block weighs exactly as much as 33 000 tons of rubble of the same block - who has suggested otherwise?

One problem is however to make 33 000 tons of rubble (density ??) impact or load anything.

 

[Dave Rogers]

An impact by a non-rigid body is by definition not an impact to start with.

What's your definition of "non-rigid" here?

Dave

 

[Dave Rogers]

Evidently a 33 000 tons rigid or non-rigid block weighs exactly as much as 33 000 tons of rubble of the same block - who has suggested otherwise?

Actually, you have. Let's take a look at where you've suggested it.

According Bazant and Seffen (read my paper) you need an intact, loose, rigid (all the time) upper block falling at a certain velocity on a structure to drive a gravity collapse of the latter, like an avalanche, until it runs out of energy.

Now Bazant and Seffen don't actually say any such thing. The stipulation that the upper block needs to be intact and rigid in order to drive a gravity collapse is purely yours. Bazant and Seffen treat the falling block as rigid and intact in order to simplify the arithmetic, as you've been told so many times it's getting boring, but still seem unable to comprehend. But why, in your fantasy, does the upper block need to be intact and rigid?

You do not know what a gravity driven collapse is, do you?. You need KE for that and it can only be provided by an intact, rigid, uniform density upper block that remains intact, rigid, with uniform density during the whole destruction of the lower structure.

Because "KE... can only be provided by an intact, rigid, uniform density upper block..."

Kinetic energy, of course, is half the mass times the square of the velocity. If KE can only be provided by a rigid, intact upper block, and since you're not suggesting that velocity of the pieces of a deformable, broken block must be zero, you're therefore either (a) suggesting that the mass of a broken, deformable block is zero or (b) unable to comprehend what you're suggesting.

Dave

 

[rwguinn]

What's your definition of "non-rigid" here?

Dave

The hell with that!
I have GOT to see his definition of "impact"!

(where is the popcorn smilie?)

 

[twinstead]

Kinetic energy, of course, is half the mass times the square of the velocity. If KE can only be provided by a rigid, intact upper block, and since you're not suggesting that velocity of the pieces of a deformable, broken block must be zero, you're therefore either (a) suggesting that the mass of a broken, deformable block is zero or (b) unable to comprehend what you're suggesting.

Can I vote for b?

 

[MRC_Hans]

*snip* An impact by a non-rigid body is by definition not an impact to start with.

*snip*

One problem is however to make 33 000 tons of rubble (density ??) impact or load anything.

I suggest you have somebody drop 33,000 tons of rubble (density of your choice) on the roof of your house. Then come back and repeat that statement. (Hint: Don't be in the house during the experiment)

I have a question for you (yes I asked it before, but you didn't answer): There was this 33,000 ton building block temporarily suspended over the lower part of the WTC1, with its supports buckled or broken. What did it do? Hover?

If it didn't hover, what stopped it?

If it didn't stop, where did it go?

Hans

 

[MRC_Hans]

Mmmm, anybody know how to make a vertical, verbal chop (without breaking forum rules)?

Seems no matter how low we swing, it goes over Heiwa's head.

Hans

 

[cloudshipsrule]

You need KE for that and it can only be provided by an intact, rigid, uniform density upper block that remains intact, rigid, with uniform density during the whole destruction of the lower structure.

So what you're saying is 50 falling marbles would have no kinetic energy, but a falling bowling ball would. Is that what you're saying?