The NIST report, start to finish

reply to post by bsbray11


Are you saying that did not happen or that you do not agree that it was the initiating event?

reply to post by -PLB-

situation 1: Upper and lower chord make up one rigid body (compressive diagonals have not failed).

This is not what your evidence you are basing your beliefs on claims so I don't know where you got this. Regardless, there would be no catenary action in this case so no pull in force on the column.

situation 2: Upper chord progressively takes over the load (compressive diagonals fail).

For this to happen bending and tensile forces in the upper chord must increase from when the entire truss was working as intended.

In situation 1 the bending stress in the lower chord is much higher than the bending stress in the lower part of the upper chord of situation 2. I don't see how this line of reasoning is wrong.

It appears you don't understand internal stresses at all. I explained stresses pretty well in my last post. There is never any bending stress in the lower chord FYI. You might want to also find out how a truss works.

The evidence I know of are the models and tests by NIST and the one in the paper. I know of no evidence that shows the complete truss will fail when only one member of the truss fails.

If your evidence doesn't include the internal forces in members and the capacity of members to resist these is it just blind faith that models are correct?

Yes. And ymax in a single chord is much smaller than ymax between two chords.

I completely contradicted your statement and you reply with yes? So you see that your reasoning was wrong? I've got no idea what you're talking about with the two chords.

So what is keeping you? In my opinion this is the major problem with the truth movement as a whole.

Time. And it's not important enough to me to spread the word about, IMO there are more important issues, but I'm not about to spend my life crusading around for justice instead of having fun. I come on the 9/11 forum when I get a period of free time because I enjoy getting involved in the debate and expanding my knowledge in this interesting subject. I'm not looking to convert anyone. Anyone who has the technical understanding and interest to carefully examine which model they wish to follow can already get access to a range of proofs allowing them to make up their mind. IMO it's more of a psychological thing. Some people are not ready to let go of faith in their government, and that's fine.

even though you made a refreshing start.

Thank you.

I would really like to see which assumptions you make and how you get to those values. For example, do you assume that the upper chord carries all the load? It seems to me the 100% catenary is never reached. I don't think all compressive diagonals buckle, and I think they will keep at least some strength. This is illustrated in figure 8(b) where you see the diagonals progressively fail. Thats what I get from the paper.

I'm curious that you named the paper as one of your sources of evidence but continue to draw entirely different conclusions to what they draw. 8(b) is the truss in transition and not in it's final state (the state that caused column failure) 8(c): "full catenary action."

And your point is that it should fail sooner? In that case, It would help to see your math.

My point is that the configuration described in the model which causes the truss to exert pull-in forces on the column is in no way possible and outside of the laws of physics. You've seen all the relevant math for this. The 322kNm moment for your theory of minority catenary action (not based on any evidence) was achieved by distributing all the load not carried by catenary action. I can provide more detail and equations if you wish.

reply to post by exponent

I'm not sure what actions you're talking about here

Actions mean the forces applied to a member or system. I can only assume they were not supplied because the actions I derived from their conclusions are not possible.

Forgive me but I read through the whole paper again and found absolutely no mention of 11.6 degrees, the nearest mention is 11.7 minutes until pull in forces developed. Perhaps you could quote it, or show me how you derived it. Solving a catenary for known deflection and arc length is a pain in the butt.

The 11.6 degrees I calculated from the claimed deflection, which was the same as the deflection you quoted me. I posted a link to the equations I used in a previous post.

That isn't true, nor did you argue just for the vertical component of the load. You argued that because the angled truss did not apply its full self weight in vertical force, then the model was inaccurate.

Not sure where you got that. I showed that under "full" or majority catenary action, the claimed actions are not possible, leaving the majority of load to still be carried in bending. I later showed them to also be not possible for a minority catenary action, with the bending moments easily failing the chord.

You cannot both argue this and then argue that a truss applying no weight whatsoever is accurate. Perhaps I missed part of your argument but this seems pretty contradictory to me.

The truss applying no weight was the hypothetical argument you brought up when you were claiming my equation was wrong at a zero degree deflection. I showed you that it was actually correct, and that the equation I used would correctly produce an applied load of zero to an undeflected catenary, as it is only possible to have an undelfected catenary if there is no load applied to it.

Originally posted by esdad71
reply to post by bsbray11

 

Are you saying that did not happen or that you do not agree that it was the initiating event?

Do you really think that the trusses could break the columns in the way that pic is showing?

Are you seriously suggesting that it was what happened?

Lightweight trusses snapped in two places 4" thick box columns, while the weak point where the trusses are fastened to the columns remained undamaged? The weaker lighter trusses remained undamaged?

This whole hypothesis just gets more bizarre, not only do sagging trusses pull in larger columns than themselves while undergoing expansion, they managed to snap the columns in two places.

[BTW that pic is showing the outer mesh, not the core, what happened to the core? I there another shot of that?)

To even get to that point you want us to believe one hour of fire can cause the trusses to expand in the first place, then for some reason manage to pull in the columns they were attached to while sagging from the expansion because they could not go anywhere else. Take note esaded, the trusses would sag IF they expanded from the heat, they can not also put a pulling force on the columns, if they could they would not have sagged in the first place. They SAG because they have nowhere else to go, neither in nor out, only down.

You could test that hypothesis in a lab and you will never be able to get that to work, I will put a wager on that mate.

Originally posted by esdad71
Are you saying that did not happen or that you do not agree that it was the initiating event?

This?:




It should be obvious if you have been reading my posts at all.

There is no evidence this ever happened, or even could happen, and it was not the initiating event.


You should actually read the past 2 pages of discussion, especially what Azp420 has been posting regarding the transfer of forces involved, and what would and would not happen first. He went into more detail about it than I ever cared to, because of the obviousness of the fact that the truss connection itself would give much sooner than the column would snap on both ends of its connections. Like I said, read the last two pages if you really want to know something about the WTC "collapse" according to NIST. It may prove very enlightening to you. Though I doubt it.

Originally posted by Azp420
It appears you don't understand internal stresses at all. I explained stresses pretty well in my last post. There is never any bending stress in the lower chord FYI. You might want to also find out how a truss works.

Take a look at figure 4 in the paper. The horizontal black arrows represent compression in the upper chord, the white arrows represent tension in the lower chord. Are you saying the paper is wrong? Can you make a drawing how the stresses should be according to you?

If your evidence doesn't include the internal forces in members and the capacity of members to resist these is it just blind faith that models are correct?

Well, again look at figure 4, it seems to me all internal forces were covered. Since you do not have any model at all (let alone one that includes internal forces), would you call your own position blind faith also? If not, why not?

I completely contradicted your statement and you reply with yes? So you see that your reasoning was wrong? I've got no idea what you're talking about with the two chords.

As far as I know you did not contradict anything, just supported what I said. I wrote "the bending stress is much lower in the lower part of upper chord". Add to that "than the bending stress in the lower chord". I did not add it because I already wrote that a couple of time so I assumed you would know what I mean. That was probably not very clever on my part, I shall try to prevent this kind of miscommunication.

Time. And it's not important enough to me to spread the word about, IMO there are more important issues, but I'm not about to spend my life crusading around for justice instead of having fun. I come on the 9/11 forum when I get a period of free time because I enjoy getting involved in the debate and expanding my knowledge in this interesting subject. I'm not looking to convert anyone. Anyone who has the technical understanding and interest to carefully examine which model they wish to follow can already get access to a range of proofs allowing them to make up their mind. IMO it's more of a psychological thing. Some people are not ready to let go of faith in their government, and that's fine.

You indeed won't convince anyone by proclaiming to know NIST is wrong and then not come with any proof to back it up. But since its not your goal, I guess thats ok. I am a bit curious though, I am not sure if you believe in conspiracies, but if you do, don't you think it is kind of your obligation as citizen to expose it? Especially when all it takes is writing a paper? I must say that I find your indifferent attitude a bit odd.

My point is that the configuration described in the model which causes the truss to exert pull-in forces on the column is in no way possible and outside of the laws of physics. You've seen all the relevant math for this. The 322kNm moment for your theory of minority catenary action (not based on any evidence) was achieved by distributing all the load not carried by catenary action. I can provide more detail and equations if you wish.

That would help a lot.

reply to post by -PLB-

Take a look at figure 4 in the paper. The horizontal black arrows represent compression in the upper chord, the white arrows represent tension in the lower chord. Are you saying the paper is wrong?

It seems you have forgotten what you were talking about. You were claiming bending stresses in the lower chord. There was never any bending in the lower chord, only pure axial stresses.

Well, again look at figure 4, it seems to me all internal forces were covered.

Perhaps you should look again at figure 4. Upon closer inspection you will notice that these were the forces in the truss at ambient temperature, and would have been the same on any other day before 9/11. They went through the time and effort to publish this worthless piece of information, but for some reason (most of us know what that is) decided against publishing an equivalent diagram for the truss when it was in its maximum deformed state and supposedly about the cause the columns to fail. Why do you think that is? Another silly error or oversight?

So far the only evidence you have is an authority saying /trust us, this is what happened.

Since you do not have any model at all (let alone one that includes internal forces), would you call your own position blind faith also? If not, why not?

I don't need an alternative model before I am able to disprove other bad models. If I don't believe in the official version of events that doesn't mean I'm obligated to have a bulletproof alternative model to switch to. I've done calculations to prove to myself that the rate of collapse of all three towers is too great to be from gravity alone. It wouldn't surprise me that a government would stage a false flag against its own citizens, as false flags have been staged before and the government has been waging a war against its citizens for the past several decades, destroying hundreds of thousands if not millions of once peaceful lives.

I could spend the time and effort developing alternative models, but I'm confident that the best minds at NIST wouldn't create rubbish models and explanations unless they were working back from a predetermined conclusion.

As far as I know you did not contradict anything, just supported what I said. I wrote "the bending stress is much lower in the lower part of upper chord". Add to that "than the bending stress in the lower chord". I did not add it because I already wrote that a couple of time so I assumed you would know what I mean.

This is what you wrote: Since the bending stress is linearly related to y, we know the bending stress is much lower in the lower part of upper chord.
Implying that the reason the bending stress was lower was due to the y value of the lower part of the upper chord. I think the miscommunication has arisen from your not understanding what the neutral axis and how the y value is determined.

The bending stress in the upper chord cannot be less than the bending stress in the lower chord, because the bending stress in the lower chord is approximately zero.

You indeed won't convince anyone by proclaiming to know NIST is wrong and then not come with any proof to back it up. But since its not your goal, I guess thats ok. I am a bit curious though, I am not sure if you believe in conspiracies, but if you do, don't you think it is kind of your obligation as citizen to expose it? Especially when all it takes is writing a paper? I must say that I find your indifferent attitude a bit odd.

I've been calling NIST claims wrong and providing mathematical proof. An alternative model is not proof, it's just an alternative model.

There are a lot more hard-working people than I producing papers and presentations. Joe Public isn't influenced by technical works though. He is influenced by what his government and media tells him.

My indifferent attitude is because like voting, my effort will be a drop in an ocean. Activists dedicate their lives to their cause, and unless they enjoy it, it's not worth it. I can think of a hundred things I'd rather do with my life than dedicate it to this cause, and many other causes that are (IMO) more important than this one. My attitude is probably odd to you because although I lead a sincere life, I do not lead a serious life (you guys should try it, it's awesome ). If anyone is interested, I owe this to the philosophy of Alan Watts, who is the most logical man I have ever heard speak (which is why his words appealed to an engineer).

That would help a lot.

Ok, here's how I got the 322kNm midspan moment:

70.4kN vertical load not taken by catenary action (calculated in previous posts) for half of a truss (9.15m). This is w, which equals 7.69kN/m (70.4/9.15)

Length of entire truss, L, equals 18.3m.

Moment at mid span = wL^2/8
=322kNm

Originally posted by Azp420
It seems you have forgotten what you were talking about. You were claiming bending stresses in the lower chord. There was never any bending in the lower chord, only pure axial stresses.

If you look at the individual members, agreed, if you look at the truss as a single body, then this pure axial stress is the bending stress. You can read about this on Wikipedia:

A truss can be thought of as a beam where the web consists of a series of separate members instead of a continuous plate. In the truss, the lower horizontal member (the bottom chord) and the upper horizontal member (the top chord) carry tension and compression, fulfilling the same function as the flanges of an I-beam. Which chord carries tension and which carries compression depends on the overall direction of bending.

This is exactly what I am saying. If this is really an unusual way of looking at it, forgive me, I am not a structural engineer.

Perhaps you should look again at figure 4. Upon closer inspection you will notice that these were the forces in the truss at ambient temperature, and would have been the same on any other day before 9/11. They went through the time and effort to publish this worthless piece of information, but for some reason (most of us know what that is) decided against publishing an equivalent diagram for the truss when it was in its maximum deformed state and supposedly about the cause the columns to fail. Why do you think that is? Another silly error or oversight?

Maybe they simply did not though it was necessary? You are now arguing the model is bunk because you did not receive enough information about it for your taste. That is a fallacy. You could contact the writers if it really troubles you, but shooting it down on sight is too premature.

So far the only evidence you have is an authority saying /trust us, this is what happened.

Basically. Its the best you can do if you want to refrain from speculation, besides from modeling or experimenting yourself. This is how I threat all scientific publications, I trust that the peer review process ensured a sound methodology, and I accept the results as trustworthy until proven otherwise. If there is no peer review, the writers can convince me to trust them by showing a respectable background in that area of science.
As for modeling it yourself, I leave that up to the people who disagree/distrust the information. Although I am afraid that we will never see anything coming from the truth movement that will be more convincing or trustworthy.

I don't need an alternative model before I am able to disprove other bad models. If I don't believe in the official version of events that doesn't mean I'm obligated to have a bulletproof alternative model to switch to. I've done calculations to prove to myself that the rate of collapse of all three towers is too great to be from gravity alone. It wouldn't surprise me that a government would stage a false flag against its own citizens, as false flags have been staged before and the government has been waging a war against its citizens for the past several decades, destroying hundreds of thousands if not millions of once peaceful lives.

We were talking about your claim that if one member fails, the complete truss fails. It seems you are easier satisfied than I am. I do need to see a model that proves this to be the case (and proves the other model to be wrong). I do not believe you on your word/intuition.

Implying that the reason the bending stress was lower was due to the y value of the lower part of the upper chord. I think the miscommunication has arisen from your not understanding what the neutral axis and how the y value is determined.

Feel free to assume that, I think I made clear what I meant.

The bending stress in the upper chord cannot be less than the bending stress in the lower chord, because the bending stress in the lower chord is approximately zero.

See explanation above.

I've been calling NIST claims wrong and providing mathematical proof. An alternative model is not proof, it's just an alternative model.

But you do not publish your results. I find that odd.

There are a lot more hard-working people than I producing papers and presentations. Joe Public isn't influenced by technical works though. He is influenced by what his government and media tells him.

My indifferent attitude is because like voting, my effort will be a drop in an ocean. Activists dedicate their lives to their cause, and unless they enjoy it, it's not worth it. I can think of a hundred things I'd rather do with my life than dedicate it to this cause, and many other causes that are (IMO) more important than this one. My attitude is probably odd to you because although I lead a sincere life, I do not lead a serious life (you guys should try it, it's awesome

). If anyone is interested, I owe this to the philosophy of Alan Watts, who is the most logical man I have ever heard speak (which is why his words appealed to an engineer).

The main problem in the truth movement is the complete lack of any serious publication. Just one publication that is sound, and disproves NIST, would cause more than just an insignificant ripple, it will shake the whole scientific community. Well, at least the structural engineering community. You really wont have to dedicate your life to it.

But everyone has his own priorities in life an I respect that.

Ok, here's how I got the 322kNm midspan moment:

70.4kN vertical load not taken by catenary action (calculated in previous posts) for half of a truss (9.15m). This is w, which equals 7.69kN/m (70.4/9.15)

Length of entire truss, L, equals 18.3m.

Moment at mid span = wL^2/8
=322kNm

Thanks, I will have to study this a bit more, I will reply to it later.

Originally posted by Azp420
Ok, here's how I got the 322kNm midspan moment:

70.4kN vertical load not taken by catenary action (calculated in previous posts) for half of a truss (9.15m). This is w, which equals 7.69kN/m (70.4/9.15)

Length of entire truss, L, equals 18.3m.

Moment at mid span = wL^2/8
=322kNm

Your calculation seems sound (although I am not much of an expert so don't pin me down on it), but your interpretation of the paper is flawed. I have read the paper again, and I have to admit I had interpreted it incorrectly also before (as I thought that the 16.1 and 18 minutes indicated failure of the truss).

You are incorrect because you apply this moment to the top chord only. But it really is nowhere claimed that the situation where the top chord carries all the load is ever reached in their simulation. In fact, their simulation stops at the moment there is a local instability. That is the moment the first compressive diagonal fails. At this moment, all other diagonals are still intact. This is also the moment where the inward pull force is ~85kN

Then they say:

Through a progressive load redistribution process, illustrated in Fig. 8(b), the compressive diagonals then successively buckle at the same temperature. Eventually, this series of local instabilities causes the remaining part of the composite truss to collapse through tension of the slab and top chord.

So situation 8c is never reached in their simulation. Their model actually agrees with your claim that once one member fails, the complete truss will (progressively) fail, given the temperature remains constant. Although they do not give a time period for this to happen.

Anyway, if you disagree with this interpretation, you should contact the writers and present your critique. If you don't really care, we should just leave it at this.

Originally posted by ANOK
[BTW that pic is showing the outer mesh, not the core, what happened to the core? I there another shot of that?)

That is one of the central issues of this entire business. In order to present a pretense of a SCIENTIFIC explanation of how the buildings could collapse they have to look for a weak spot and exaggerate and propagandize everyone with it.

The horizontal beams in THE CORE just about completely disappear.

I just did a calculation recently. The length of horizontal beams on each level in the core had to be at least twice the length of the vertical height of columns in the core at each level. So what would that do to its ability to absorb and transfer heat without weakening?

When do any EXPERTS on either side of the issue point that out?

Where is there a diagram of how the horizontal beams in THE CORE were laid out?

psik

reply to post by psikeyhackr

That is one of the central issues of this entire business. In order to present a pretense of a SCIENTIFIC explanation of how the buildings could collapse they have to look for a weak spot and exaggerate and propagandize everyone with it.

So the analysis of the building collapse SHOULD NOT have looked for weak spots in the construction and design? I would think you would want to consider weak areas. They may lead to some hint of why the building collapsed.

The horizontal beams in THE CORE just about completely disappear.

Huh?

I just did a calculation recently. The length of horizontal beams on each level in the core had to be at least twice the length of the vertical height of columns in the core at each level.

Or just look at the spacing between the vertical columns, the length of the horizontal beams should equal the distance they span.

So what would that do to its ability to absorb and transfer heat without weakening?

Sorry, nothing. Nothing that is capable of "transfering" heat is capable of doing so without heating itself, and any rise in temperature results in a loss of strength.

When do any EXPERTS on either side of the issue point that out?

There are no experts on both sides of the issue. The so-called experts that propose that the buildings collapsed by any other reason the impact of the planes and the resulting fires are not "experts".

Where is there a diagram of how the horizontal beams in THE CORE were laid out?

The NIST examined the as-built plans, why don't you ask them?

reply to post by psikeyhackr


That is what NIST does. They look for the weak spots...the places that need to be corrected in order to make sure that it does not happen again in future buildings. The also work in numerous other fields of science. The new WTC7 is a prime example. I am not going to provide a link or a list but there were dozens of changes for specific codes for construction based off the NIST findings and testing.

This explains in a concise manner read what they were expecting to accomplish with the WTC investigations.

www.nist.gov...

Now, NIST is not just about burning buildings and I know that it is easy to try to discredit by simply saying they do not staff engineers and scientists in the number of those that have joined the AE911 Truth.

These are some of the other things they do and research...take a look...

www.nist.gov...

The WTC had a cool,unique design based on a tube frame that was designed for maximum office space and it depended on the inner and outer columns by design. Now, I have seen the video of the washers on here, and it is a nice example. However, the mass of the floors is taken into account. Take that same experiment, and put an 5 inch plate on each one, and then create an outer column that it attaches to. Now, take away the outer support and see what it looks like. It needed the inner and outer columns. Inner columns were cut and outer columns failed. One or the other may have allowed it to stand but not both. Again, just a thought.

I feel that NIST did what it was supposed to do. If anything, if it would appease, I would agree to reopening the investigation but only if it was privately funded.

Originally posted by esdad71
reply to post by psikeyhackr

 

That is what NIST does. They look for the weak spots...the places that need to be corrected in order to make sure that it does not happen again in future buildings. The also work in numerous other fields of science. The new WTC7 is a prime example. I am not going to provide a link or a list but there were dozens of changes for specific codes for construction based off the NIST findings and testing.

But that doesn't PROVE the weak spot could result in the destruction of the ENTIRE BUILDING.

That is not any excuse to totally ignore the HORIZONTAL BEAMS IN THE CORE.

At some point it ceases to be science and BECOMES A LIE.

10,000 pages and they can't specify the tons of steel and tons of concrete that were on every level. This should go down in history as the most ridiculous decade in history. PhD physicists can't build a model that can collapse like the north tower. ROFL

psik

reply to post by psikeyhackr


Your argument that they did not include the weight of the concrete then therefore it must be all delusion is literally a joke.

Also,more than 30 floors of the South tower core and north tower core were still standing seconds after the collapse. This means that part of the building did it's job but without the outer core it was not able to work with the inner and it fell.

Here is a video of the north tower that shows how it sheared the lower floors and there is no pancake.

www.youtube.com...

Originally posted by esdad71
reply to post by psikeyhackr

 

That is what NIST does. They look for the weak spots...

But what is shown in that video still is NOT a weak point, yet it is very close to a weak point that somehow didn't fail, the point where the truss is fastened to the column.

The truss itself would fail before it could snap the much larger 4" thick box columns, let alone the welds, bolts.

Remember when you were all emphasizing LIGHTWEIGHT trusses a few weeks ago, because you all thought it made the trusses seem more liable to failure? Well what happened to that argument now? According to NOVA the trusses were stronger than the main columns holding them up and all it took was a little sagging to collapse the whole building.

How are you going to rectify your contradiction now?

reply to post by ANOK


Lightweight trusses? Not me. What are you referring too?

Originally posted by esdad71

Here is a video of the north tower that shows how it sheared the lower floors and there is no pancake.

Your vid shows nothing of the sort. Try a vid where you can actually see what is happening, note the top starts to drop independent of the bottom.



Why do you keep saying there was no pancake when all your posts argue for a pancake/progressive collapse?

I keep asking you this and you never answer?

We KNOW there was no pancake collapse because the evidence does not support it, and other energy must of been involved. BUT if it didn't pancake, and no explosives were involved, then how do you think it collapsed? I thought your argument was floors fell on floors, adding weight, and forcing the other floors to collapse? That IS a pancake/progressive collapse.

You can't stop at initiation and think that explains everything. The initiation did not remove the resistance of the lower structure.

Please clear up your argument, because you are all over the place.

Originally posted by esdad71
reply to post by ANOK

 

Lightweight trusses? Not me. What are you referring too?

Maybe not you personally but c'mon you know OSers were calling them lightweight trusses, and I never saw you correct any of them.

So what are they now heavyweight trusses?

But regardless you didn't address the important points of my post as usual. All you do is look for something to disagree with whether it's relevant to the discussion or not.

Anok,

OK, so you show a video also that shows that the top is falling separately from the bottom at the point of the airline impacts.

Also, pancake and progressive are two separate things. It was a progressive collapse based on a few factors, not one. It did not simply fall at free fall speeds and destroy the building. In the end, the cores and the outer columns of lower floors were still there on both towers.

It is simply the design which if it had columns across the floors as all other buildings, they would have had a better chance. Not that it is incorrect or faulty but it was not designed for what happened.

I am not stopping at initation.Once we agree on the initiation then it is time to talk collapse.

Originally posted by esdad71
reply to post by psikeyhackr

 

Your argument that they did not include the weight of the concrete then therefore it must be all delusion is literally a joke.

Also,more than 30 floors of the South tower core and north tower core were still standing seconds after the collapse. This means that part of the building did it's job but without the outer core it was not able to work with the inner and it fell.

Here is a video of the north tower that shows how it sheared the lower floors and there is no pancake.

www.youtube.com...

That is an interesting interpretation of STILL STANDING.

For most of the building to come down in less than 18 seconds that means 50% of gravitational acceleration from the top. So regardless of all of this trivial drivel about sagging cores the upper portion of the north tower would still have to accelerate that stationary mass. So to not have accurate data on the distribution of that stationary mass is totally unscientific.

psik