WTC collapses - Layman's terms again

[Humanoid]

Hm - a 33 000 tons ship at 5 m/s (10 knots) horzontal speed at collision has evidently more (2.78 times!) KE than an upper block of WTC 1 (also 33 000 tons) but only contacting vertcally the lower structure at 3 m/s.

The contact area is also very different. The ship's bow is pointed, the upper block is a 4000 m² floor flat. Assuming uniform density of the upper block and uniform impact over 4000m² the impact pressure is pretty low. The peak pressure is time dependent but remember - the columns only occupy 0.13% of the floor area. The rest is the upper floor of the lower structure that is subject to the pressure. Actually the same pressure is applied to the lowest floor of the upper block.

The ship collision may stop after a penetration of 5-10 meters into the other ship (of same size). The pointed bow of the striking ship really breaks the side of the stricken ship but after a while (even if the driving force of the striking ship is still on) the destruction is arrested.

Why the upper block of WTC 1 would cause the lower structure to collapse is beyond me. See .

I would expect that only the columns of the upper block and the lower structure would slice the floors apart of respective parts and that the floors would get entangled as seen in the right figure of the link above. Two walls of the upper block may then have sheared off and fallen to the ground. The rest of the upper block remains in the top of the lower structure. The lower structure would still stand. Quite basic actually.

So pls re-do your energy calculations using my observations.

Kind regards

Heiwa

In case I missed something in the preceeding gagillion pages of babble, I must speak out on this, sorry if this is old territory but...

The ship travelling at 10 knots begins to decelerate I.E. slow down.

The top floors of the WTC are undergoing a constant accelleration of 10 meters per second, per second, thereabouts (more like 9.8...ish)...

Lets get simple and look at what happens when the upper structure first falls, and hits the floor below:

The top floors starts with a downward velocity of 0.
It falls.
It accellerates.
It reaches (by your calculations) 3 m/s.
33,000 tons (your figure)
= 3,300,000 kg * 3ms-1 = 9,900,900 kgms-1 of momentum
Which strikes the floor below the falling section.

OK. So what happens now? Obviously, the upward part will slow down, maybe break up a little, but the floor beneath will most probably (and in fact did) give way due to the inability of the load bearing beams to support the incredible forces on top of it.

So what is the status of the system now? Well, if (as was the case) the top floors did not reach a speed of 0 (i.e. they were still moving downwards, even just a little bit), then we can repeat the steps for the next floor, only now the starting velocity is greater than 0, and the mass of the upper section includes the structure of the floor that just got crushed. This gives the falling debris even more power to punch through the next floor, as it will be moving faster and have more weight.

Also some other stuff you mentioned, the columns are likely welded or bolted together or a combination of both, as such they will have weak spots at the joins which when a gagillion tons of building is dragging them down and inwards will cause them to snap, not tangle up like some kind of gargantuan ball of wool...

But then that is just my thoughts I am no expert at all in anything.

 

[Panoply_Prefect]

Apollo20/Frank

Remind you that topic is: "How could WTC1, 2 collapse due to gravity forces alone after some local failures up top?" If you want to discuss other topics, pls start a new thread about it.

Actually no, its not. Its "WTC collapses - Layman's terms again " - so asking you for an alternate theory is perfectly within topic.

So, Heiwa, WTC collapses, in layman's terms - what ever made those two towers crumble to the ground?

On a sidenote, your answer to ""How could WTC1, 2 collapse due to gravity forces alone after some local failures up top?", is "It couldn't" - so even if that were the topic, it would be perfectly on topic to ask you for an answer to, "Well, if it couldn't, then what ever did happen".

Then again, you don't really want to get into that "no planes, all just photoshopped, there were thermite all over", do you?

 

[pomeroo]

Not at all. OT of course. T is why collapse arrest is not considered. I am just depressed by all these ghastly strumpets without manners filling the thread with garbage. With the moderator sleeping at the switch? Living in an 1-D world must be ... tight?

Talk about sleeping at the switch--YOU have had your errors corrected repeatedly by real engineers and you haven't advanced a step beyond your original wrong-headed position. Living in a fantasy world must be... dumb.

 

[Heiwa]

In case I missed something in the preceeding gagillion pages of babble, I must speak out on this, sorry if this is old territory but...

The ship travelling at 10 knots begins to decelerate I.E. slow down.

The top floors of the WTC are undergoing a constant accelleration of 10 meters per second, per second, thereabouts (more like 9.8...ish)...

Lets get simple and look at what happens when the upper structure first falls, and hits the floor below:

The top floors starts with a downward velocity of 0.
It falls.
It accellerates.
It reaches (by your calculations) 3 m/s.
33,000 tons (your figure)
= 3,300,000 kg * 3ms-1 = 9,900,900 kgms-1 of momentum
Which strikes the floor below the falling section.

OK. So what happens now? Obviously, the upward part will slow down, maybe break up a little, but the floor beneath will most probably (and in fact did) give way due to the inability of the load bearing beams to support the incredible forces on top of it.

So what is the status of the system now? Well, if (as was the case) the top floors did not reach a speed of 0 (i.e. they were still moving downwards, even just a little bit), then we can repeat the steps for the next floor, only now the starting velocity is greater than 0, and the mass of the upper section includes the structure of the floor that just got crushed. This gives the falling debris even more power to punch through the next floor, as it will be moving faster and have more weight.

Also some other stuff you mentioned, the columns are likely welded or bolted together or a combination of both, as such they will have weak spots at the joins which when a gagillion tons of building is dragging them down and inwards will cause them to snap, not tangle up like some kind of gargantuan ball of wool...

But then that is just my thoughts I am no expert at all in anything.

Quote OK. So what happens now? Obviously, the upward part will slow down, maybe break up a little, but the floor beneath will most probably (and in fact did) give way due to the inability of the load bearing beams to support the incredible forces on top of it. Unquote

The upper part - or upper block as we call it - may break up a little?? The bottom of the upper block consists of a very thin floor 4000 m² large that was designed to carry say 100 kgs/m² of furniture and humans. And now you drop that whole floor on a solid column below ... and you think the floor may break up a little. A little?

Pls, think again.

And the KE of a 33 000 tons ship at 5 m/s is 2.7777 times bigger than an upper WTC 1 block at 3 m/s. But the ship has a side that carries much more than 100 kgs/m² (the upper block bottom!).

But forget the upper block dropping at 3 m/s. It is just a simple conspiracy theory invented by some gangsters to allow stupid scientists to calculate KE. No upper block dropped at any speed. The upper block is demolished before that - easy to see on any video.

 

[CHF]

Heiwa,

when can we expect to see your theory as to why the WTC towers collapsed?

 

[Humanoid]

Ok, so to clarify what you are trying to say to me it would be extremely helpful if you could answer some easy questions. Given the time you have spent trying to convince everyone of your claims I think a fresh approach is needed. I am open to all ideas, but I have difficulty swallowing an entire paradigm in one sitting, so, rather than try and understand every claim you are trying to make all at once, it would help to start with the basics of what you are saying and work from there so I can truly build the foundation of a greater understanding. As such I have presented my questions as multiple choice and I would appreciate if you could spend the small amount of time picking which letter belongs to each of my questions.

1. From the choices below, which do you think best describes the most likely state of the top floors at the beginning of the collapse of each tower?

2. From the choices below, regardless of what really happened, which scenario would produce the most downward force on the floors below?

3. From the choices below, regardless of what really happened, which scenario would produce the least downward force on the floors below?

A. 12 or so stories of a WTC tower falling from height as a solid hunk?
B. 12 or so stories of a WTC tower falling from height as a slowly "upwardly pancaking" hunk?
C. 12 or so stories of a WTC tower smashed into car sized pieces?
D. 12 or so stories of a WTC tower smashed into briefcase sized pieces?
E. 12 or so stories of a WTC tower smashed into fist sized pieces?
F. 12 or so stories of a WTC tower pulverized into dust?
G. None of the above (please explain)


Although my mind is open on this issue, I can't help wondering what the answers to this question is - though I don't want to be the one to find out in any case:

4. From the choices below, which would cause the most damage to your body if dropped on your head from a height of 3 meters?

A. 12 or so stories of a WTC tower falling from height as a solid hunk?
B. 12 or so stories of a WTC tower falling from height as a slowly "upwardly pancaking" hunk?
C. 12 or so stories of a WTC tower smashed into car sized pieces?
D. 12 or so stories of a WTC tower smashed into briefcase sized pieces?
E. 12 or so stories of a WTC tower smashed into fist sized pieces?
F. 12 or so stories of a WTC tower pulverized into dust?
G. None of the above (please explain)

 

[DC]

Dopped on a body???????

when you want to switch the towers with something else to use it as an excample, then use 2 things that are the same.
not steel construction on a human body, or a solid block dropped on a spring.
take one body and cut it in 2 and let them drop on eachother.

its sad enough Bazant et all are not able to do that, they had to replace the upper part with a solid body. while they didnt replace the lower part ith a solid body.

they even go so far to try to prove that crush down and crush up cannot happen at the same time, so they justify their crush down first.

while videos clearly show, Crush up started before crush down started.

 

[Humanoid]

No upper block dropped at any speed. The upper block is demolished before that - easy to see on any video.

Then where did it go? Did it go up? Sideways?

The only way I can see it went, is down. Onto the floors below. Falling. Dropping. Accelerating under gravity, either as a solid lump or small pieces it would not make much difference, unless only one thing I can see as an exception would be the concrete and steel being pulverized to a floury powder - but how would such an act be accomplished? I have yet to see any explosive capable of silently and completely pulverizing rock AND STEEL into a fine powder... So, the rubble must have gone down, explosion or no explosion.

Or wait, are you saying that the upper block xylophoned upwards on the floor below??? OH I get it now...

Interesting theory... I'll think about it some more and can you please still answer my multi choice quizz above? Cheers

 

[Humanoid]

Dopped on a body???????

when you want to switch the towers with something else to use it as an excample, then use 2 things that are the same.
not steel construction on a human body, or a solid block dropped on a spring.
take one body and cut it in 2 and let them drop on eachother.

its sad enough Bazant et all are not able to do that, they had to replace the upper part with a solid body. while they didnt replace the lower part ith a solid body.

they even go so far to try to prove that crush down and crush up cannot happen at the same time, so they justify their crush down first.

while videos clearly show, Crush up started before crush down started.

Really I was just trying to add a touch of missing light heartedness, I didn't mean for it to come across as mockery if that is how it seemed. When things get serious I tend to make stupid jokes to try and relieve the tension.

Questions 1, 2 & 3 are serious ones though, I would really like answers.

 

[DC]

no steel got pulverized. parts of the concrete is pulverized, Dr. Greenings provided a formula for that calculations.
a big part of the perimeter steel columns falls down on the ground, next to the tower.

crush up "consumed" energy, mass that is not hitting the lower floor will not provide energy to the collapse. the falling debris on the ground will provide energy to the ground, that can bee seen on the seismic data.

 

[Brainache]

no steel got pulverized. parts of the concrete is pulverized, Dr. Greenings provided a formula for that calculations.
a big part of the perimeter steel columns falls down on the ground, next to the tower.

crush up "consumed" energy, mass that is not hitting the lower floor will not provide energy to the collapse. the falling debris on the ground will provide energy to the ground, that can bee seen on the seismic data.

So how much of the mass of the upper block missed falling on the lower floors? 5%, 10%, 20%, 50%? Or was it just some of the outer collumns and a lot of dust from crushed wallboard?

 

[DC]

So how much of the mass of the upper block missed falling on the lower floors? 5%, 10%, 20%, 50%? Or was it just some of the outer collumns and a lot of dust from crushed wallboard?

someone made a very good attempt about that, in his huge claculation, i hope he will release that soon.

btw, when you want numbers, how much energy did the crushing of the wallboards consume?

i know 1 wallboard is not that much ressistance, but i remember a demolition expert talking about something like that.

NOVA: Can you describe the prep work that goes into dropping a building.

SL: Well, it depends on the structure, obviously. We've had chimneys prepared in half a day and we've had buildings that take three months. Generally we don't do the preparation work. We are usually an implosion subcontractor, meaning that there is a main demolition contractor on site, who's been contracted by the property owner or the developer, and they then subcontract the implosion to us. We will then ask them to perform preparatory operations, including non-load bearing partition removal—meaning, the dry wall that separates the rooms. It's not carrying the weight of the building. It's just there as a divider. But what happens—you know, if you have a case of beer—all the little cardboard reinforcements inside? If you have all those little cardboard reinforcements, then you can jump up and down on the case. But if you take them out, the case will crush under your weight. Those little partitions actually add up and act as stiffeners. So that's one of the first things we strip out. The second thing we do is drilling. Depending on the height of the structure, we'll work on a couple of different floors—usually anywhere from two to six. The taller the building, the higher up we work. We only really need to work on the first two floors, because—you can make the building come down that way. But we work on several upper floors to help fragment debris for the contractor, so all the debris ends up in small, manageable pieces. Other preparatory operations are covering—wrapping the columns with chain link fence and then in geotextile fabric, which is very puncture resistant and has a very high tensile strength. It allows the concrete to move, but it keeps the concrete from flying. The chain link catches the bigger material and the fabric catches the smaller material from flying up and out. We also sometimes put up a curtain around the entire floor, to catch the stuff that gets through these first two layers. That's really where your liability is.

 

[Humanoid]

no steel got pulverized. parts of the concrete is pulverized, Dr. Greenings provided a formula for that calculations.
a big part of the perimeter steel columns falls down on the ground, next to the tower.

So I missed an option: Steel framework completely intact, concrete pulverised?

But... I must be getting my wires crossed because I thought that the critical, load bearing structures were all made of steel, with gyprock (drywall) cladding for decoration... Essentially, I assumed that if you somehow removed all the concrete, marble, gyprock and other non-steel elements from the framework, the tower would still be able to stand on its own merits. (edit - I may be completely wrong here! experts?)

crush up "consumed" energy, mass that is not hitting the lower floor will not provide energy to the collapse. the falling debris on the ground will provide energy to the ground, that can bee seen on the seismic data.

The impact of a falling 12 story section hitting the floor below it would send a shock wave down the building and into the ground, which would also show up on the seismic data.

Crushed up debris are not consumed energy, they still begin to fall as soon as their lower supporting members are stripped away, all accelerate down at the same speed, most appear to fall through the center of the building.

The center of the building was where the horizontal supports basically tied the vertical columns together. These horizontal supports were designed to hold the columns steady horizontally, they were not designed for a vertical downward impact, so as the debris cascaded through the center of the building in a twisting maelstrom of tens of thousands of tons of steel and rubble, it ripped away these horizontal supports as it fell. As more supports were consumed, the vertical columns were no longer tied together and began to fall to the sides and break away in large sectons.

The only way this could not happen is if most of the mass from the upper floors blew sideways instead of downwards. The only evidence of any sideways falling is the splaying steel columns as they lose their horizontal supports, and a billowing cloud of dust. You could take all the dust which billowed from the entire world trade center collapses, and I bet you a beer that it wouldn't be anywhere near as much mass as even a single floor of the building.

Having said that, how does one pulverize concrete to dust? Is it aggregate concrete too, like with a mix of stone, sand and cement? Does it pulverize the stone within the aggregate, or does this method of pulverizing concrete do... what? I will do a search for the research you have referred to here, but I would be most interested to see a demonstration of this in effect outside of the WTC collapses.

 

[DC]

The impact of a falling 12 story section hitting the floor below it would send a shock wave down the building and into the ground, which would also show up on the seismic data.

can you point out that "energy" in the saismic data pls?

 

[dommyboysinjapan]

Heiwa,

Then we have the clowns that try to be funny on the thread without adding any substance ... and they are not funny at all. Then the monkeys that just chatter about something else than the topic. Sad that the Moderator does not delete all that nonsense.

I've noticed this too.

You can decide yourself to what group you belong. Clown or monkey or both?

How about none of the above.

Or contribute to the topic with some constructive thinking. Always welcome.

It is difficult for me to understand or perceive how and why the building would collapse in a manner that is different than what you were describing. Your theory is a lot more plausible and informative than NIST's copout stating that global collapse is then inevitable without reference to any specific collapse sequence. (What the heck were they talking about in those 10,000 pages if they completely failed to outline or even provide theories for collapse sequences after the collapse had been initiated?)

 

[Architect]

But forget the upper block dropping at 3 m/s. It is just a simple conspiracy theory invented by some gangsters to allow stupid scientists to calculate KE. No upper block dropped at any speed. The upper block is demolished before that - easy to see on any video.

As ever, the whole world is wrong...except you. People such as Arup (who design tower blocks for a living), the university engineering departments, and engineers/architects the world over are all wrong.

Really, nothing is going to convince you. You ignore fundamental mistakes in your arguments and instead employ useless analogies such as "cotton wool" and "plastic table".

 

[Humanoid]

can you point out that "energy" in the saismic data pls?

From the Greening report "Energy Transfer in the WTC Attack"

Seismic data recorded at various sites in New York State on September 11th,
2001, show two significant events, the first at about 9:59 a.m. (EDT) and the second,
slightly more powerful, at about 10:28 a.m. (EDT). Traces of the seismic events may be
viewed at www.ldeo.columbia.edu, and show a lot of “ringing” decay extending over 10
or more seconds. Thus, cursory inspection of the traces suggests that the WTC collapse
events were indeed “about 10 seconds” in duration. However, since the correct
interpretation of the seismic data is critically important to the analysis of the collapse of
the two WTC towers, we will now consider the seismic data in more detail.
The first event, occurring at about 9:59, was the collapse of WTC 2, also called
the south tower, (N.B. This was not the first tower to be hit by an aircraft). The north
tower, WTC 1, collapsed at about 10:28 and was responsible for the second seismic
disturbance. The traces recorded at the Palisades station provide the best seismic data for
the events of September 11th, 2001. Because the published traces begin at 9:59:07 (WTC
2) and 10:28:30 (WTC 1), these times are frequently quoted as the actual collapse times.
This is erroneous for two reasons. First, it should be noted that the start of the major
oscillations in the seismic signature of each collapse event corresponds to the ground
impact of the main upper section of the towers. As TV coverage of the event shows, this
impact occurred about 10 seconds after the start of the collapse of each tower. Second,
the Palisades seismic data are delayed by about 17 seconds compared to the actual events
in New York City because of the travel time for the 34 km distance between the towers
and the Palisades seismic station.
The CNN TV coverage of the collapse of the North Tower (WTC 1) provides a
very useful time calibration of this event that may be compared with the Palisades
seismic data. The CNN TV images show that WTC 1 starts to collapse at 10:28:23. The
ground impact of the upper section follows about 10 seconds later at 10:28:33. This is
consistent with the Palisades data if we allow 17 seconds for travel time of the seismic
waves. Thus, if we treat the Palisades data as if it were recorded at the WTC site, the
published seismic trace would now effectively begin at 10:28:13 and the ground impact
responsible for the large oscillations of the trace would occur at 10:28:32. These values
are in good agreement with the visual result derived from the CNN TV images.
Having made these adjustments to the timelines of the 911 seismic data we are
able to conclude that the small ripples in the traces of the WTC collapse events - ripples
that precede the period of large oscillations - represent the first stage of collapse as
defined more precisely below. The seismic signal for this first stage is small, as would be
expected, since kinetic energy is being transmitted to the ground only through the steel
support structure. Furthermore, a significant fraction of this kinetic energy is being
absorbed as the energy needed to buckle and crush the structural elements of the
buildings. The major seismic signal of each collapse is generated by the ground impact of
falling debris, and constitutes what we will call a second stage of collapse. Given the
above considerations and a careful evaluation of the seismic data, it is estimated that the
first stage of collapse took 11.3 1.5 seconds for each WTC tower. We will show in the
following Section that the second stage of collapse added 1 – 2 seconds to the total
collapse times.

This is taken directly from the Greening report you refer to, and it seems to support that the seismic activity is, in duration and timing in direct correlation to the start and end of the collapse of each tower.

I'm still hunting for the actual seismographs of the event if anyone has a link handy...

 

[DC]

someone made some pretty good calculations into that, using greenings formulas and others. very interesting, not completly correct yet, i hope Urichs new paper will deliver some new usefull input, his mass calculations did already.

those calculations are not yet publicy avaible, but he made alerady a little docu about it.
but its in german, all the explenations to the Calculations and the Excel sheet are all in german needs translations first. but you can already take a look at it on youtube. Spoken in german, but text on screen is english.

http://de.youtube.com/user/achimspok

 

[dommyboysinjapan]

Suggested answers to your questions

Humanoid,

As such I have presented my questions as multiple choice and I would appreciate if you could spend the small amount of time picking which letter belongs to each of my questions.

Thank you for your politeness. It is appreciated. please allow me to present my layman speculations on your question.

1. From the choices below, which do you think best describes the most likely state of the top floors at the beginning of the collapse of each tower?

2. From the choices below, regardless of what really happened, which scenario would produce the most downward force on the floors below?

3. From the choices below, regardless of what really happened, which scenario would produce the least downward force on the floors below?

A. 12 or so stories of a WTC tower falling from height as a solid hunk?
B. 12 or so stories of a WTC tower falling from height as a slowly "upwardly pancaking" hunk?
C. 12 or so stories of a WTC tower smashed into car sized pieces?
D. 12 or so stories of a WTC tower smashed into briefcase sized pieces?
E. 12 or so stories of a WTC tower smashed into fist sized pieces?
F. 12 or so stories of a WTC tower pulverized into dust?
G. None of the above (please explain)

1) I think G. None of the above does because 'falling from height' carries the implication that it was weight that was freefalling downward. This might be true had all the perimeter and all the 47 support collumns been severed completely and at the same time at that level. As we know not all or even most of the perimeter collumns were severed, nor were all of the support collumns completely severed at the level of impact.
2)A
3)F (When you think about it this supports the theories that are advanced by Jim Hoffman, Steven Jones, and other Truthers who say the collapses couldn't have thoroughly pulverized all the buildings into dust in a manner in which it did yet still have the mass to crush the larger in tact, structurally sound sections of the buildings below the impact zones.)

4. From the choices below, which would cause the most damage to your body if dropped on your head from a height of 3 meters?

A. 12 or so stories of a WTC tower falling from height as a solid hunk?
B. 12 or so stories of a WTC tower falling from height as a slowly "upwardly pancaking" hunk?
C. 12 or so stories of a WTC tower smashed into car sized pieces?
D. 12 or so stories of a WTC tower smashed into briefcase sized pieces?
E. 12 or so stories of a WTC tower smashed into fist sized pieces?
F. 12 or so stories of a WTC tower pulverized into dust?
G. None of the above (please explain)

I think the answer to this question is A but I feel that it bears absolutely no comparrison to the situation regarding the collapse of the Towers. Its comparing apples and oranges.

 

[Humanoid]

#1:
To my understanding the ground impact greening is referring to is the final moment when all the accumulated debris of the collapse strikes the ground, an entire buildings worth of rubble coming to an almost immediate stop as it hits the ground.

From what I gather you seem to be saying that your understanding of the ground impacts is that they are falling debris seperate to the collapsing building. Am I correct in my understanding of your interpretation of the ground impacts?

#2
"The seismic signal for this first stage is small, as would be
expected, since kinetic energy is being transmitted to the ground only through the steel
support structure" - Greenings own interpretation... It seems reasonable to me, what else would account for these readings which directly correlate to the first stages of collapse?