Senior Research Scientist Proves that Planes and Fires Caused Collapse

Originally posted by LeftBehind
With that paragraph taken out of context is does appear that way, however you notice that he isn't leaving it at that assumption. He clearly states that he goes into it in depth in section 4.2. In that section he actually calculates the value for E1.

...

So as you can see he is not just guessing or lying about the value for E1. In fact he is breaking down his position peice by peice to fully account for all of his figures something completely lacking in the Jones paper.

The final figure he comes up with is that the collapse times were affected by the lost energy by 0.2 and 0.1 seconds for WTC1 and WTC2, respectively.

What he stated there was clear: "This suggests that This suggests that E1 is relatively small compared to the kinetic energy associated with the falling blocks of floors; let us now place this qualitative prediction on a quantitative basis."

And in the relevant section, 6.0 or what-have-you, the author does just that. It's starting with a conclusion and fixing information around it. NIST did the exact same thing.

Where does this 80% of the mass figure come from? I would agree that 80% of the debris was ejected outward. However the steel, which was most of the mass, ended up in a huge pile at the base of the towers.

I've posted photos above showing the whole Ground Zero region. Can you line up that "mountain of steel" with an area on an image from the air, showing the whole lot? Steel was ejected just as everything else was. In fact, it was a several-thousand-pound piece of steel that landed something like 600 feet away from one of the buildings, was it not? There was definitely force there to launch the steel, and it didn't just fall straight down through the dust cloud to the ground.

external image


The question is how much of it was added, and what amounts of fragmented debris were deflected, and which were actually concentrated enough to cause decent damage. Look at the above images of flying steel, then the above images of Ground Zero. [Note: the pictures of Ground Zero are now on the previous page.]

It doesn't look like much at all was available, LeftBehind, and even less that wouldn't be deflected.

And certainly you don't think that the cap remained intact? And you realize that the building was falling onto thicker and thicker columns? All of these things matter, you know.

How does the collapse speed not slowing immediately indicate that?

The energy available would not be infinite, obviously. The author of that paper allows that the energy would be greatly diminished over the course of the collapse, but maintains that the building would still be utterly decimated at a constant rate, descending upon heavier columns with less materials. Such behavior is not consistent with the official story, but with additional sources of energy that became available in a sequence upon each floor.

As you can see from the graph Greening made from his figures the resistance is readily apparent.

...

Starting at the same speed and then slowing is exactly what we should expect from the resistance as the collapse proceeded.

Yeah, but that didn't happen, lol. There was no slowing. I would think you'd have caught on to that by now. Watch this video, which was taken from below the South Tower, showing some floors being blown out in a steady sequence. You can even see tons of the "squibs" coming out in symmetrical rows floor by floor if you have the guts to look.

That video is relatively short and only has one angle, though. If you want to download a longer video, look at this one, which shows a number of camera angles (of which 3 are relevant) and longer views so that you can really see how the tower is falling.

I may get the figures to actually show that there couldn't have been a decrease in collapse velocity tomorrow if I can find something to indicate when the actual collapse reached the ground (maybe some seismic stuff?), but I have a research paper due tomorrow that I haven't started and it's getting late.

[edit on 29-1-2006 by bsbray11]

Once again Bsbray you are taking his words out of context.

Here is his final thoughts on those figures.

It is very encouraging that the energies reported in Table 1 show an acceptable balance between the energy inputs to the towers and the energies dissipated by the destruction of the aircraft and the WTC floor supports. For our calculations to show this level of internal consistency argues well for their validity. And while we acknowledge that the energies in question could be determined with greater precision by more detailed calculations, we would suggest that the values in Table 1 are a useful first approximation.

Emphasis added.


If you take the time to read the whole thing he clearly lays out where he gets these figures. Taking one quote out of context and then saying he's making things up is disingenous.

Read the whole paper. He is clearly not starting with a conclusion and then fitting in his figures to meet his conclusion.

As to the mountain of steel.

Yes. Here are a ton of pictures showing these huge piles of twisted steel in the footprint.

www.glasssteelandstone.com...

And as Valhall has previously pointed out, the debris would only pile up so high before spilling down.

Honestly though, without being able to see in the cloud we cannot be certain exactly what was happening to the obscured areas.

Greening does a good job of using physics and equations to back up his paper. On the other hand we have the Jones paper which fails to show any equations and comes across like an op/ed peice.

Why are you insisting that the collapse never slowed down?

You have said that you know it didn't fall at free fall, so obviously some resistance was encountered. Please don't make me post that free fall pic again.


Now, my question for you. Do you have better figures for what happened during the collapse?

Where has he made mistakes in his equations?



BTW, the heavier columns would still not be able to withstand the forces being applied to them. Are you trying to say that you expected the towers to collapse a few floors and then stop?

Originally posted by Phoenix
Ok, even with the flying debris calculated (on the high side IMHO) then the seemingly accepted number for weight of WTC 1 or 2 is around 300,000,000 Kg divided by 110 = roughly 2,720,000 Kg per floor then subtract 80% to arrive at an added 544,000 Kg's additional momentum per floor for each floor overtaken in addition to the total weight of how ever many floors were above the original collapse point.

Well, this issue is getting more confusing now. Because Lyte Trizzle has u2u'd and stated their group doesn't have a number for the mass and that I can't state I'm using their number in any calculations. This is extremely problematic because in essence, what has happened here, is L.T.'s group has claimed Greening's work is worth nothing due to the "most important parameter" being in error by 200,000,000 kg, but now states they don't have any number at all that I can use to re-run Greening's calculations to get the new collapse time toward verifying my numbers.

I don't understand how that number can be used to diminish one man's work, but then is useless for other work.

I am very skeptical that 80% ejecta is even close to the true figure and agree with Valhal that a little common sense is in order. Visually the videos can not be relied upon for this figure most of that is a dust cloud of very much lighter weight particles - is there any expert evidence to support 80% or is that just a non-expert opinion formed from watching the video.

Couldn't we at least get an estimate based on the final "heap height"? Are there any semi-accurate measurements of what each tower's pile height was after the collapse was over?

[edit on 1-30-2006 by Valhall]

Originally posted by bsbray11


And certainly you don't think that the cap remained intact?

I may get the figures to actually show that there couldn't have been a decrease in collapse velocity tomorrow if I can find something to indicate when the actual collapse reached the ground (maybe some seismic stuff?), but I have a research paper due tomorrow that I haven't started and it's getting late.

[edit on 29-1-2006 by bsbray11]

Two things bsbray...

One, I think there is video evidence that indicates the "cap" (but I need to be sure we're using that term the same way) was intact. I'm using it as at least the "roof" of the building", and not assuming anymore than that. Please see my second video link in the post I had early on in this thread.

Two, is there some particular reason we can't use both my work with your work (i.e. my work shows 18 second collapse time), and that's with the "roof" hitting the ground (which would actually be the pile, right?)

Just because we don't see these things the same way, doesn't mean that either one of our work shouldn't be considered by the other, and I'd be curious to see what using my collapse time would do for you.

And then a follow-up, realizing that the lower floors were made stronger than the upper floors, don't you think there would, in fact, possibly be a slowing - that's not from any calculations but just from intuitive reasoning. If not a slowing, possibly a leveling out of sorts?

I actually want to rephrase this question to you bsbray:

And then a follow-up, realizing that the lower floors were made stronger than the upper floors, don't you think there would, in fact, possibly be a slowing - that's not from any calculations but just from intuitive reasoning. If not a slowing, possibly a leveling out of sorts?

Okay, for every floor impacted there will be a measurable Jerk (which is the mathematical term for the derivative of acceleration) and that Jerk will be a negative change in acceleration downward of whatever is impacting a given floor, right?

So for the sake of simplicity let's pretend for a minute that once a floor is impacted and fails and causes a negative Jerk to the floor(s) impacting it, that the next 10 feet are freefall. What I'm trying to verify with you is, don't you agree that as the impacted floors get lower (into the stronger constructed floors) the negative Jerk will increase?

That's funny...

This guy is so credible and right, when his story CLASHES with the official story he's trying to support! The official story says that the plane impacts didn't bring the buildings down, but fire. This fire wasn't from jet fuel, but from the combustible office items, furniture, and paper in the buildings.

See, if they stuck to the planes and jet fuel, they'd have a hard time explaining building 7. With this as the "official" story, they have all bases covered.

This guy smells like a disinfo agent to me...

Originally posted by LeftBehind
And as Valhall has previously pointed out, the debris would only pile up so high before spilling down.

I find it hard to believe that that huge mess at Ground Zero was even largely the result of some pile "spilling down."

Why are you insisting that the collapse never slowed down?

You have said that you know it didn't fall at free fall, so obviously some resistance was encountered. Please don't make me post that free fall pic again.

Consider this: the towers did not start at free fall. They did not finish at free fall. But the speed in which they did fall, was maintained. See, this has nothing to do with the actual velocities of collapses. I don't think you really get where I'm going with this.

Now, my question for you. Do you have better figures for what happened during the collapse?

No, because as far as I know there are no reliable figures as to how much resistance any given floor would exert.

Where has he made mistakes in his equations?

I have already pointed these out. He assumes all the mass was added to the falling mass, and that this mass was maintained throughout and never decreased. The assumption is wrong. The collapse actually happened backwards to the logic he offers in that paper: most mass was lost, and even what was not lost should've largely been dismembered into pieces that could easily be deflected, given the size of the debris.

BTW, the heavier columns would still not be able to withstand the forces being applied to them.

The idea is that more resistance is being presented on the way down, but I don't think you caught on to this idea in the first place (see above).

Are you trying to say that you expected the towers to collapse a few floors and then stop?

Yep. If they began to fall at all, anyway. Shouldn't have even started, looking at the fires/heating.

Yes, there's the issue of a good portion of the mass falling outside the footprint, thus being incapable of crushing the structure and smaller pieces falling within simply being deflected as physics dictates. But all of that is ignoring one major issue with the general pancake theory and its derivatives:

How could the loadbearing columns fail simultaneously?


Also, what's with AgentSmith's chronologically impossible answer? I know for a fact that it was there right after I submitted my post, therefore I can exclude any system delays or timestamp errors as explanation. Did you look into it, Valhall?

[edit on 30-1-2006 by Lumos]

Originally posted by Valhall
I think there is video evidence that indicates the "cap" (but I need to be sure we're using that term the same way) was intact. I'm using it as at least the "roof" of the building", and not assuming anymore than that. Please see my second video link in the post I had early on in this thread.

The cap as I use it implies the "blocks" of floors above the impact zones. This means somewhere around floors 97/98 to 110 for WTC1, etc. (all of those floors -- the falling "object"). I take it that you don't mean this? We really should get some standard terms in usage.

These blocks of floors were diminished/disintegrated as the collapses progressed. For example, the images that can be found of large sections of broken-up perimeter columns falling over the side of a building at free fall are most likely from the cap of that building, given the massive amount of damage done to everything under those caps to render the debris into much smaller pieces.

Two, is there some particular reason we can't use both my work with your work (i.e. my work shows 18 second collapse time), and that's with the "roof" hitting the ground (which would actually be the pile, right?)

Just because we don't see these things the same way, doesn't mean that either one of our work shouldn't be considered by the other, and I'd be curious to see what using my collapse time would do for you.

And then a follow-up, realizing that the lower floors were made stronger than the upper floors, don't you think there would, in fact, possibly be a slowing - that's not from any calculations but just from intuitive reasoning. If not a slowing, possibly a leveling out of sorts?

(Answered together)

Ok, what we need to estimate is how much of a loss of velocity there was in the collapse speeds, from initiation to completion. That means we'll have to pick a time for a collapse's finish (maybe even both to compare the two towers -- that would be best).

I don't have any problem with the number 18 itself, but before we pick a time we have to make sure that nothing is being overlooked and everything is as accurate as possible. A big problem with looking at a video alone is obviously that you can no longer see the actual collapses beyond a certain point, so then we turn to the seismic charts, and they're not so easy to decipher either, as you can hardly tell what activity has caused what seismic reading.

Also, were you taking the collapse of the spire into account? I don't think I have that clear, but I wouldn't include it as part of the time. Reasoning for this is that I think different charges were used to destroy the perimeter columns (ie the charges that resulted in the squibs, especially the rows upon rows of them as seen in some of those ground-level video shots). When the spire fell, it was just straight down upon its base WTC7-style. I don't know what would have caused that, but obviously not the same things used for the perimeter. The perimeter collapse time is what I'm looking for here; it's what's most relevant to the issue I want to focus on with lack of velocity loss, etc.

But anyway, once we get a time hammered out and agreed upon (maybe even a couple or so if it comes to it), then here's my suggestion for what we do next:

1) Determine the collapse velocity of either (or both) tower(s) after initiation. For WTC2 this should exclude the time spent bowing outwards from the angular momentum, but start when the vertical collapse begins (I know where a close-up showing this can be found so don't fret the exact moment). I'd have to look at WTC1 again but I think it falls at a decently constant rate from the very start.

2) Track that velocity for as long as we possibly can, making note of any apparent velocity changes, and then when we reach low enough parts of the towers that no video is available, use the perimeter collapse time figures to estimate how much longer the collapse would've taken from what is observable.

3) Take the remaining time and calculate whether or not there would have been a significant change in velocity for the portion of collapse that we can't observe in videos.

What do you think?


P.S.

So for the sake of simplicity let's pretend for a minute that once a floor is impacted and fails and causes a negative Jerk to the floor(s) impacting it, that the next 10 feet are freefall. What I'm trying to verify with you is, don't you agree that as the impacted floors get lower (into the stronger constructed floors) the negative Jerk will increase?

Yes, I agree with this. That's why I think the velocity remaining relatively constant, despite this, and all the mass loss, not to mention that the energy was not infinite to begin with, constitute a valid problem with the official story's logic.

And I know that was just an example, but if there were really 10 feet or so of freefall, I would think the collapse would be pretty "jerky"-looking.

[edit on 30-1-2006 by bsbray11]

Thanks bsbray11.

Yes, first thing first let's get nomenclature down. Because I agree with you that YOUR cap (lol) would disintegrate as it traveled down (because if a progressive collapse occurs we have to assume the damage would occur both to the impacted floor and the impacting floor so we're destroying two floors at a time basically - maybe not one for one but you get my point).

So we'll use "cap" as the part that started falling (at the failure point) and then mine will be roof

If bsbray or Valhall or someone else would agree on a few points I could figure up the initial velocity, force or impact on the next existing intact floor as a starting point for figuring out the rest of the puzzle. These numbers are key to later velocity that you guys are talking about in above posts.

Heres what I need;

number of intact floors of the "hammer"

agreement on average weight of each floor including vertical elements and "live" load.

agreement on number of floors compromised by aircraft impact.

distance traveled before "contact" with anvil. (verticle distance of compromised floors not initially providing much resistance)

do this for both wtc1 and wtc2

Someone may have done these calcs already - at least it would shed light on the actual forces that are to be considered when extrapolating how the collapse mechanism worked.

I cannot find these estimates in other posts but the are so many it would be easy to miss.

Phoenix

Hhere is the rest of the debunk of greenings paper that explains WHY his conclusions don't hold true with an incorrect mass....

Calculations and all.....

With the actual mass of the building at live load it does not come to 1.5kwh.

This is what i got.

Ti= 1/2 (330, 000, 000/110) x (8.5)2 = 108, 375, 000 J that is 59, 693, 181.82 J less than the figure Greening got!!!


If we use the dead load this is what we get: 55, 501, 136.36 J!!!! That's less than the difference in energy of the live load vs Greenings magic number!!!



KE for the combined floors: Ta = 1/2 (330, 000, 000/110) x (8.5/2)2 = 27, 093, 750 Joules



Now let's calculate that energy for the floor collapse.

The KE before impact is show below



T1 (wtc) = 14 X 1, 083, 750, 000 = 1, 517, 250, 000 J

T2 (wtc) = 29 x 1, 083, 750, 000 = 3, 142, 875, 000 J



The KE lost as heat is calculated as follows



Q (WTC 1) = 1/(1 + N) x Ti (WTC 1) = 14/15 x 1, 083, 750, 000 J = 101, 150, 000 J

Q (WTC 2) = 1/(1 + N) x Ti (WTC 2) = 29/30 x 1, 083, 750, 000 J = 104, 762, 500 J



The precent of energy lost as heat for each tower:



Tower 1 = Q/T1 x 100 = 6.67 percent

Tower 2 = Q/T2 x 100 = 3.33 percent



One thing Greening forgot to mention was how much energy was also lost as sound and that is something that can't really be calculated unless decible readings were taken, then we can calculate the energy lost to sound as well.



OH before I forget to mention it....the weight of one floor is NOT 4, 360, 000kG!!! It is in fact 3, 000, 000Kg. and that is our live load!!!! the dead load is actually 1.56 million Kg per floor.



Moving on.....



If we now assume, as previously

discussed, that the yield strength of the core columns is about 6.7 times higher than the

yield strength of the exterior columns, we estimate that an additional 3.60 ? 108 J are

required to collapse the 47 core columns supporting each floor. Thus, based on T.

Wierzbicki et al. calculation, we estimate a total of 6.29 ? 108 J of impact energy was

required to collapse one WTC floor, a value that is remarkably close to Baants estimate

of 5.0 ? 108 J for the plastic energy dissipated by the collapse of one floor.



Greening says 62, 900, 000, 000 J is required to collapse one floor of the WTC Towers....



Now as you can see from my calculations.....it isn't even close to that!!!



The maximum kinetic energy of each WTC tower collapse occurred at the end of

the 1st stage of the two-stage collapse. At this point in time the falling material, consisting

of at least 80 floors weighing about 370, 900, 000 kg, was moving at about 50 m/s. We will therefore assume that each tower had a maximum kinetic energy of



x 370, 900, 000 x (50)2 J or 4.6 ? 1011 J.



Again because his mass is wrong....this throws everything off again...



80 floors equates to 72.2% of the building....so we multiply that by the mass of the building and we get the weight of the 80 floors.



The figure we get is 240, 000, 000Kg!!! Which is about 130, 900, 000 KG difference!!!!



so let's do the kinetic energy



1/2 x 240, 000, 000 x (50)2 = 30, 000, 000, 000 J.



Greening Got 46, 000, 000, 000 J so we have a difference 16, 000, 000, 000 J of energy here!!!



From photos of the debris pile produced by each WTC tower collapse it is evident

that steel columns and trusses, aluminum fasciae, glass windows, gypsum wallboards and

other construction materials were all fractured and pulverized to varying degrees during

the collapse events. Thus only a fraction, f, of the 4.6 ? 1011 J of kinetic energy, was

available to crush the WTC concrete. For the present calculation we will assume a value

for f of ~ 0.75, giving 3.5 ? 1011 J of available kinetic energy.

Lets consider the beginning of the 1st sage of the collapse of each tower. For

WTC 1 we will take as an example 14 floors, and for WTC 2, 29 floors impacting the

floor below with a maximum velocity of 8.6 m/s. It follows that the kinetic energy on

impact was ? 14 ? (510, 000, 000/110) ? (8.6)2 joules = 2.4 ? 109 J for WTC 1, and the

K.E. was ? 29 ? (510, 000, 000/110) ? (8.6)2 joules = 5.0 ? 109 J for WTC 2. If we

assume 50 % of this energy was available to crush concrete, we have 1.2 ? 109 J available

for WTC 1, and 2.5 ? 109 J available for WTC 2. This is sufficient to crush the concrete

on the impacted floor to 175 ?m particles.

Some have suggested that even if Greening used an incorrect value for mass that his calculations still hold true and that a smaller mass would still lead to a collapse. This is not true as demonstrated here:


Tower 1: X 14 ? (510, 000, 000/110) ? (8.6)2 joules = 2.4 ? 109 J for WTC 1, (Greening)



1/2 x 14 x (330, 000, 000/110) x (8.6)2 = 1, 517, 250, 000 J Almost 1.5 billion J Difference!!!!



Tower 2: x 29 x (510, 000, 000/110) x (8.6)2 joules = 5.0 x 109 J for WTC 2. (Greening)



As a scientist Greening should know that rounding off numbers skews your results...in fact the correct figure for that calculation is 4, 857, 170, 455 J



1/2 x 29 x (330, 000, 000/110) x (8.6)2 = 3, 142, 875, 000 J



a difference of 1, 714, 295, 455 J!!!!!



Now if 50% of the energy is required to crush the concrete this is what we'll get for both towers:



Tower 1: 1/2 x 1, 517, 250, 000 J = 758, 600, 000 J

Tower 2: 1/2 x 3, 142, 875, 000 J = 1, 571, 437, 500 J



Consider now the newly formed mass of (14 + 1) floors of WTC 1, and (29 + 1)

floors of WTC 2, impacting on the floor below. Because of momentum transfer, the

impact velocities are slightly lower than the 8.6 m/s impact speed for the first floors hit:

8.1 m/s for WTC 1, and 8.3 m/s for WTC 2. The maximum kinetic energy prior to impact

is x 15 x (510, 000, 000/110) x (8.1)2 joules = 2.3 x 109 J for WTC 1, and x 30 x (510, 000, 000/110) ? (8.3)2 joules = 4.8 ? 109 J for WTC 2.

This is essentially the same result as the previous impact calculation and the kinetic energy released is therefore also sufficient to crush the concrete on the impacted floor to 175 ?m particles.



This is where he goes wrong!!!! HE says it requires 190, 000, 000, 000 J to crush concrete to 100 micro metre particles!!! Guess what; we don't have that enery!!!!



Let's do it using his 15 and 30 floor results


for 15 floors I got: 1, 625, 625, 000 J

for 30 floors I got: 3, 251, 250, 000 J



Greening got: 2, 300, 000, 000 J for 15 floors and 4, 800, 000, 000 J for 30 Floors.



See the big mistake!!!!


Frank Greening:
"Finally, we will calculate the energy needed to crush all the concrete in a single

WTC tower (= 48, 000, 000 kg) to particles of a specified size. As we have noted before,

the energy required to crush all of the concrete in one tower to 60 ?m particles = 3.2 ?

1011 J which is only slightly less than the 4.6 ? 1011 J of energy available. However, the

energy required to crush concrete to 100 ?m particles is 1.9 ? 1011 J, which is well within

the crushing capacity of the available energy. Hence it is theoretically possible for the

WTC collapse events to have crushed more than 90 % of the floor concrete to particles

well within the observed particle size range.'



WRONG!!!! WRONG!!! WRONG!!!!

Originally posted by Phoenix
If bsbray or Valhall or someone else would agree on a few points I could figure up the initial velocity, force or impact on the next existing intact floor as a starting point for figuring out the rest of the puzzle. These numbers are key to later velocity that you guys are talking about in above posts.

Do it for WTC1, since that building would've had the most trouble having a global collapse naturally.

Here's what I say:

Heres what I need;

number of intact floors of the "hammer"

13.

agreement on average weight of each floor including vertical elements and "live" load.

We have no way of knowing this for sure.

Estimates I'm more inclined to buy assert 200,000 tons (ie Trumpman

200,000/110 = 1818.18...

Note that the topmost floors, ie the "block," were much lighter than the lower floors for obvious structural reasons.

agreement on number of floors compromised by aircraft impact.

No whole floors were compromised.

For WTC1, floors 92 through 98 were damaged, but we're talking less than 15% perimeter column damage total in this region, and similarly less core damage. Therefore, to assume any whole floor as compromised will offset your results severely. I don't recommend you do that if you want a fair analysis.

If you want, instead, take that region (6 floors total), and take out the equivalent of about 13% of the structure. That would give you a more accurate assessment (as close as we can possibly get probably), but not 100% accurate.

distance traveled before "contact" with anvil. (verticle distance of compromised floors not initially providing much resistance)

None. Structural resistance from the start; there was no empty space to drop upon.

do this for both wtc1 and wtc2

Like I said, WTC1 would be easier. We can agree that they came down similarly; whatever caused the collapse of one would've caused the collapse of the other, and even if not, the demolition of only one building is certainly still a crime. If WTC1 could collapse naturally via 13 floors vs. 97, then certainly WTC2 could do the same with a heavier driving mass.

Also!!

Can you explain how exactly you're going to calculate the resistance provided by the steel in the building?

Obviously, falling through a WTC-sized mass of compacted cotton is going to yield different results than a WTC-sized block of solid steel, even if they have the same weight. So from where exactly are you getting this variable? It's the variable the rest of us have been missing this whole time: we don't know exactly how much resistance would be provided by any given floor.

Granted I'm no physicist and don't understand how exactly this works, but I think what you're going for is the impulse, right? The change of momentum over time, or something like that? And we haven't been able to come up with a resistance figure for that, and thus no calculations. So I'm just wondering how you're going to be dealing with that issue in your calcs.

Originally posted by LeftBehind
As to the mountain of steel.

Yes. Here are a ton of pictures showing these huge piles of twisted steel in the footprint.

www.glasssteelandstone.com...

What are you talking about here? Looking through these slides I see
maybe one or two pieces of twisted aluminum, a few slightly bent pieces
of steel, but certainly no huge piles of "twisted" steel.

BTW, the heavier columns would still not be able to withstand the forces being applied to them. Are you trying to say that you expected the towers to collapse a few floors and then stop?

Yes. Unless the buildings collapsed by earthquakes are the anomalies
here. Why have there never been buildings that collapsed due to earthquakes that pulverized themselves?

bsbray

According to a uniform building code book I have the density of lightweight concrete is that which weighs less than 115 lbs per cubic foot.

Is that agreeable to you?

What square footage of total floor area and percentage of penetrations for elevator shafts etc. do you use?

I use an average thickness of 6" (could be as much as 8") for the concrete floor, do you agree?

I am talking to a structural engineer about relative strength of columns, my opinion from photos is they were not crushed, many bent, but rather the welds and attachment points were the weak spot. Also many can be assumed to have had lateral forces acting on them along with the vertical component especially the exterior columns, I'm not refering to the "bow" before collapse but rather the debris "push" (lateral) once in motion.

Live load (equipment, files, cubes, furniture, partitions etc.) 50psf which is a very very common rating in the industry.

I come up with 107.5 lbs per sq/ft for floor.

I still don't get how you're going to figure the impulse. Where are you getting the resistance figures for the lower building?

According to a uniform building code book I have the density of lightweight concrete is that which weighs less than 115 lbs per cubic foot.

Is that agreeable to you?

What square footage of total floor area and percentage of penetrations for elevator shafts etc. do you use?

I use an average thickness of 6" (could be as much as 8") for the concrete floor, do you agree?

Dunno; show me some construction drawings of the complex and maybe I could tell you.

Look at the first image on this page if you want to take some floor charts from other places on the internet and try to match up what's what, which probably varied from floor to floor. I would trust that image more than ones from FEMA or NIST, simply because it was published in a book released before 9/11.

I am talking to a structural engineer about relative strength of columns, my opinion from photos is they were not crushed, many bent, but rather the welds and attachment points were the weak spot. Also many can be assumed to have had lateral forces acting on them along with the vertical component especially the exterior columns, I'm not refering to the "bow" before collapse but rather the debris "push" (lateral) once in motion.

How much damage could you seriously expect from lateral forces during this collapse? Well, at least imagine a hypothetical situation of the WTC falling under their own weight. What lateral forces were in the actual collapses, you have to understand, are going to be argued as shaped explosives. Thus you see all the debris flying outward in amazing proportions (ie around 80%) in videos.

Natural lateral forces would be pretty much non-existant, man. You would have the rare beam being pinched from torsion maybe, but I don't even really see that as a major problem there because of how unlikely it would be for such a thing to occur naturally in those circumstances.

Most of the force was obviously vertical; any lateral forces present would have to result from the vertical forces (excluding explosives), thus making them automatically (a) secondary to the vertical forces, and (b) only possible as a result of unusual circumstances during the collapse, ie the torsion from just the right solids at just the right time.

To blame the collapses on that sort of thing, just doesn't add up. You have all the same problems of the collapse physics, as well as the logical problems of the assertion itself, and to maintain constant speed and symmetry through all of that would be damned near impossible. It would be about as likely as me passing through a physical object via quantum theory; astronomically unlikely, if not impossible in the first place.

Live load (equipment, files, cubes, furniture, partitions etc.) 50psf which is a very very common rating in the industry.

Not for the WTC Towers. There, you're looking at 50 psf for the perimeter columns, but 100 psf for the core columns, with the core structure handling about 60% of the load at least.

From Trumpman's paper:

The dead load of a floor was 1,818 tons. The floor area was rated 40-150 psf (1.9-7.18 kPa), depending on what the area was going to be used for. Higher load ratings generally were for areas that would support larger than normal loads such as mechanical equipment. Below are floor load estimates based on a review of WTC data contained in a 2005 NIST report.

And the included NIST data shows variations floor by floor, but none of them are so low as 50 psf. Between floors 94 and 110, you have mostly 75 psf for each floor, except for a couple 100's and a 150 psf. And rememeber -- these were the topmost floors, which were designed to carry the least load! Obviously, the lower floors of the building would be carrying a much larger load. It wouldn't make sense architecturally for the weights/loads to not taper as the building height increased; even NIST admits thicker columns in the base.

Trumpman used a lot of NIST figures to come up with each floor being able to withstand 11,075 tons of load before failing. Now, that's per floor. Static weight, too. What you need to find is the impulse, right? The change in momentum of the downward movement of the top floors onto the rest of the building.

If we were dealing with static weight (and of course we are not), then you would have 23,634 tons of WTC falling upon a structure that could withstand 1,074,275 tons before each and every floor was destroyed. The thing is, you have to change that 23.6k tons into moving energy, and you have to likewise change that 1,074.3k tons into resistance to get the negative impulse. Even though I haven't been able to do that, I have to say that it doesn't look very good for those 13 floors.

Also keep in mind that that driving mass of the top floors disintegrated during the whole process, so what you're faced with in the end is the impossible feat of a severely downsized, if not non-existant driving mass of the "block" plowing through thicker columns and heavier floors at about the same rate as the collapse started off at. So there's something additional to take into account: the driving mass disintegrates as the problem is carried out. Small debris would be subject to deflection and would not offer much crushing force.

[edit on 14-2-2006 by bsbray11]

bsbray

Most misunderstand the term "live" load

It is the allowable weight of non-structural items IE: they are all loads introduced to a floor after the struture is built.

Typical is 50-80psf in open floor areas, core areas usually are 100psf for equipment and such, yes lower columns have to be stronger to support both the combined live load and dead load which is the actual weight of the permanent structural elements along with wind load.

I'm not prepared to argue the squib theory as of yet.

The lateral force simply explained comes into play much as dumping a load of dirt and rock into a container - there is "force" on the sides is there not?

I view it this way - the intact exoskeleton of structural beams form the "container wall (for very short time) catching the debris from areas above, granted some will spill out the top as can be seem in video showing heavier elements falling out of dust cloud - this action is allowed specifically because there was indeed some resistance offered by the structure as surmised by the fall time you and Valhall seemed to agree on. A fair proportion of that debris would have made lateral force outwards on the exoskeleton.

I believe that once the forces involved are stated in plain english then some headway might be made.

I am starting from that premise and if it works it works, if it does not then squibs can be considered - but one step at a time eh.

Originally posted by Phoenix
bsbray

Most misunderstand the term "live" load

Ah, I think I just calculated the block weight using dead load. Maybe add a 1/3 to that or something; Trumpman has the figures. Bottom floors potential still dwarf it.

The lateral force simply explained comes into play much as dumping a load of dirt and rock into a container - there is "force" on the sides is there not?

Upon the columns of a floor that was already destroyed by a vertical force maybe; the debris would not be pouring into undamaged floors and causing damage before the vertical force reached them. Aside from illogical, it would also be impossible given the trusses/concrete slabs.

I view it this way - the intact exoskeleton of structural beams form the "container wall (for very short time) catching the debris from areas above, granted some will spill out the top as can be seem in video showing heavier elements falling out of dust cloud

Actually, most of the debris landed outside of the footprint, illustrating that most of the debris was ejected outwards during the actual collapse. Estimates done by Hoffman argue about 80% of the mass actually landed outside of the footprints. That would be about 20% falling straight down on any given floor.

- this action is allowed specifically because there was indeed some resistance offered by the structure as surmised by the fall time you and Valhall seemed to agree on.

Resistance is one interpretation; another is a sequence timed to appear just slower than free-fall. Watch the collapses and try to find where the momentum dissipates and a serious loss of velocity occurs in either tower.

A fair proportion of that debris would have made lateral force outwards on the exoskeleton.

Very little in proportion to outwardly ejected mass, and only on floors that have already been subject to great vertical force to rip open the trusses -- and then you would have to assume that the falling material missed most of the columns as it fell vertically through the trusses and concrete (or what remained), just to bounce off of smack out columns with a lateral force from torsion or deflection, which would greatly diminish the energy available in the first place.

I believe that once the forces involved are stated in plain english then some headway might be made.

The forces you are suggesting would necessarily be weaker than the vertical force, as well as dependent upon that force to continue collapsing the building. If the vertical force decreased, the deflected lateral forces would have to decrease. What you are suggesting requires both to remain pretty constant, and you simply did not have that in the WTC1 collapse. You had the opposite: the vertical forces would necessarily diminish as the amount of mass diminished (since the force is directly dependent upon the amount of mass first of all, and its speed, etc.). Especially given how fast and seamlessly the building collapsed, and how symmetrical, etc., it really doesn't seem likely at all to me that random lateral ejections of steel beams could have collapsed those buildings. They would be pretty random, after all: the insides of those buildings were far from solid steel chunks or truckloads of nothing but gravel; there would've been a lot of room for those beams to miss on each and every floor, as the falling floors lost more and more mass.

[edit on 14-2-2006 by bsbray11]

Again, since my question was washed over, why have buildings
that were collapsed by earthquakes simply fallen over and
never pulverized themselves, even a little bit.