So Just Fire Brought Down WTC7 In A Perfect Free Fall Collapse ?, page 18

posted on Jun, 23 2013 @ 01:30 AM

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Originally posted by -PLB-
You really fail at understanding that the floor connections fail before they can cause this whole "pressure wave".

They would have to fail faster than the speed of sound in steel.

Do you believe in magic?

Yes.

Wow, no, I really didn't know that. I'm quite sure that a large percentage of floors need to be made to fail in a controlled demolition, not just a few.

Well this would be a great moment to extend your knowledge.

...and a great moment for you to back your claims.

a) vérinage demolition utilizes hydraulic cylinders and pulleys and removes load-bearing walls beforehand

Though you can not deny that the building is still standing strong after these preparations beforehand.

I can only invite you to read EP 1 082 505 B1 yourself, I can't coerce you.

:-) Nice try. Please allow me to stress that the evidence I had the honour to prese and different buildings - clearly shows that the interruption of a progressing collapse is nothing out of the ordinary and even common if the charges don't go off as planned, which in turn backs my not-so-extraordinary claim that the floors have to be weakened just in time in order to facilitate the uniaxial collapse of a tall building.

Again the incorrect inductive reasoning. Get a logic course at your local university. Just because some buildings show some behavior does not mean all buildings do. Logic 101.

You have two related buildings, damaged in 2% of the floors each on the same morning, that cannot stop the progression of total uniaxial collapse compression once initiated, and deduce all tall structures will show this behaviour so you don't have to come to the conclusion that these buildings were damaged by more than just planes and fires. I give you two unrelated buildings that are meant to be demolished and still the progression of the uniaxial collapse comes to a halt to back up my claim that the inevitability of total progressive collapse theory has no ground to stand on.

All without a logic course at my local university.

You, on the other hand, are the one defending the extraordinary assumption that once collapse is initiated, progression is inevitable, so you are the one to come up with extraordinary evidence - other than the subject of the debate.

Labeling something "extraordinary" does not make is so. A government conspiracy that deludes all experts in the world, how would you classify that?

Everyday business.

For whether it happened or not is not the question, the question is how and why it could happen. Planned demolition is the ordinary assumption. Failure of 2%-15% of the floors (for example because of fires and some localized structural damage due to a plane crash or a suitcase bomb or a gas leak) and inevitability after initiation is the extraordinary assumption.

Its not. Physics does not care about what you call "extraordinary". If you want to make a case, show the physics.

I am happy to do so and have done so for the past weeks. I show you physics, logic, magic, whatever you want. But I can only show you the door, you know, I'm not going to push you through it. If you choose to refuse to accept an argument well and strongly made, nothing can force you to understand it. There is a saying in my language "man's will is his heavenly kingdom".

I, on the other hand, understand your unwillingness and hesitance to see and accept the obvious, because it's not just the towers - it's the experts, the politics, a complete world view depends on it. But since you're here debating this instead of leaving those "conspiracy theorists" alone, there seems to be a part of you that wants to understand and know the truth (since I don't want to insinuate you're just here for some tasty troll fodder). Noone will give "the" truth to you, though. You'll find it yourself one day, if you really want to.

-PLB-

posted on Jun, 23 2013 @ 12:57 PM

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Originally posted by Akareyon
They would have to fail faster than the speed of sound in steel.

Ok, let me rephrase that. You really fail at understanding that the floor connections fail before they can cause this whole "pressure wave" which is supposedly arresting the collapse.

What is important is just the force on the floor connections, or in other words, the resistance they offer. And yes, there will be some resistance. But it has little significance to the collapse progression. Which is evident by the collapse time, which is mostly determined by inertia, not by the (other) resisting forces.

Funny thing is that I never seen anyone made an estimate of these forces, while people, like you, still claim they should have been able to arrest the collapse. To most people it is very obvious that these forces could never have been large enough to stop the collapse. It would seem to me that its priority number one for people who believe they were to prove this by showing the physics.

You have two related buildings, damaged in 2% of the floors each on the same morning, that cannot stop the progression of total uniaxial collapse compression once initiated, and deduce all tall structures will show this behaviour so you don't have to come to the conclusion that these buildings were damaged by more than just planes and fires. I give you two unrelated buildings that are meant to be demolished and still the progression of the uniaxial collapse comes to a halt to back up my claim that the inevitability of total progressive collapse theory has no ground to stand on.

All without a logic course at my local university.

Where exactly do I deduce that "all tall structures will show this behaviour"? I would really take that course if I were you as your logic is still flawed. Just because some buildings do not progressively collapse after a single floor failure does not mean that all buildings don't. Likewise, just because some buildings do show progressive collapse after a single floor failure does not mean that all buildings do. I have no idea what percentage of buildings do and which don't. Though I am suspecting that most high rise buildings do. But thats just based on my gut feeling.

Another part where you logic goes wrong is that videos of buildings where progressive collapse is expected but goes wrong is evidence that progressive collapse has no ground to stand on. If it has no ground to stand on, why did the demolition experts expect it to happen then?

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waypastvne

posted on Jun, 23 2013 @ 01:24 PM

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Originally posted by -PLB-

You really fail at understanding that the floor connections fail before they can cause this whole "pressure wave".

Originally posted by Akareyon

They would have to fail faster than the speed of sound in steel.

Thats funny, I have cut steel many times using a guillotine shear. The shear doesn't operate at a speed faster than the speed of sound in steel. In fact the large hydraulic ram that drives it takes about 5 seconds to complete a cycle, that's way under the speed of sound in steel.

The shear strength of A 36 steel is around 45 ksi if the force exceeds this, the steel fails, it's that simple.

Originally posted by Akareyon

I was pretty sure I had mentioned this and this one, as they are my favourites - the first one for the music and the other one for the huge "BOOM!" flag :-

Can you show us some videos where the fall of the top part of the build, is arrested by the lower portion of the building ? That is what you claim should happened. In both of your videos the lower portion of the building is crushed all the way to the ground.

FirstCasualty

posted on Jun, 23 2013 @ 05:42 PM

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Originally posted by waypastvne
Thats funny, I have cut steel many times using a guillotine shear. The shear doesn't operate at a speed faster than the speed of sound in steel. In fact the large hydraulic ram that drives it takes about 5 seconds to complete a cycle, that's way under the speed of sound in steel.

The shear strength of A 36 steel is around 45 ksi if the force exceeds this, the steel fails, it's that simple.

I really don't think that you are any where near in the same context as the poster you are quoting.

Can you show us some videos where the fall of the top part of the build, is arrested by the lower portion of the building ?

In demolition the basement is the first thing to be blasted out. That i believe is to make sure that the base doesn't put as much resistance. I believe there is ample testimony from ground zero that explains there WERE explosions in the basement before the collapse.

That is what you claim should happened. In both of your videos the lower portion of the building is crushed all the way to the ground.

That is the top 85% crushing the bottom 15%. Not the other way around as was the case with the two WTC towers. That would be like you tossing your loveable 3 year old child up in the air, only when you tried to catch the little munchkin, you were crushed into a pile of bone.

hellobruce

posted on Jun, 23 2013 @ 05:45 PM

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Originally posted by FirstCasualty
I believe there is ample testimony from ground zero that explains there WERE explosions in the basement before the collapse.

care to show us this testimony of "explosions" in the basement before the collapse?

FirstCasualty

posted on Jun, 23 2013 @ 06:39 PM

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Click here to learn more about this warning.

Akareyon

posted on Jun, 24 2013 @ 02:08 AM

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Originally posted by -PLB-

Originally posted by Akareyon
They would have to fail faster than the speed of sound in steel.

Ok, let me rephrase that. You really fail at understanding that the floor connections fail before they can cause this whole "pressure wave" which is supposedly arresting the collapse.

There is nothing to understand, because it is not true. They cannot fail before partially transmitting the force to the rest of the structure. The pressure wave will travel through steel at 4000 - 5000 m/s. So if you have a steel bar that is 4 km long and exert a force on one end, a portion of this force will reach the other end one second later. If a point along these 4km is too weak to sustain the pressure as the wave comes rolling, it will fail there. All the surplus energy - that which does not go into deforming that particular point - will still be there and keep the pressure wave rolling. That's why in a car crash the deformation is not concentrated on the collision area only (but foremost, since the pressure wave reaches it first, and therefor buckles the weakest parts here first), but also other parts of the car distant from the collision area.

So by the time the floor connections fail, the pressure wave has already distributed a huge portion of the forces all over the structure.

Not so in the Towers, where all the forces concentrated on one floor after another.

Funny thing is that I never seen anyone made an estimate of these forces, while people, like you, still claim they should have been able to arrest the collapse. To most people it is very obvious that these forces could never have been large enough to stop the collapse. It would seem to me that its priority number one for people who believe they were to prove this by showing the physics.

Why, I have done so.

If each tower had a mass of 250,000 tons, the first floor holds up 250,000 tons, that's a force of 2452500000 Newton.

Second floor holds up 250,000 tons * 109/110, which is 2,430,204,545 Newton.
Third floor holds up 250,000 tons * 108/110, which is 2,407,909,091 Newton.
Fourth floor holds up 250,000 tons * 107/110, which is 2,385,613,636 Newton.
...
Onehundredninth floor holds up 250,000 tons / 110, which is 22,295,455 Newton.

Which sums up to an upward force of 134,887,500,000 Newtons. Multiply that with a factor of safety of 2, and we have 270 Giganewton for the whole structure.

If the top 15 blocks (34090909 kg / 334,431,818 Newtons) reached ground level in 14 seconds, a=2*345m/14²s²=3.5 m/s², so the friction force was F=34*10^6 kg * (9.81 - 3.5) m/s² = 214 Meganewton.

0.214 GN vs. 233 GN, that's one hell of a moment :-)

Just because some buildings do not progressively collapse after a single floor failure does not mean that all buildings don't. Likewise, just because some buildings do show progressive collapse after a single floor failure does not mean that all buildings do. I have no idea what percentage of buildings do and which don't. Though I am suspecting that most high rise buildings do. But thats just based on my gut feeling.

And you are absolutely sure it is not based on the effort to rationalize the unique self-compression phenomenon exhibited - so far - only by WTC 1, 2 & 7 on September 11th, 2001, without the help of cutter charges, explosives, alien laser beams, space-based high-energy microwave weapons or a bunch of Taliban secretly and intelligently rasping predetermined failure points into each and every column?

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-PLB-

posted on Jun, 24 2013 @ 02:26 AM

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Originally posted by Akareyon
So by the time the floor connections fail, the pressure wave has already distributed a huge portion of the forces all over the structure.

No, the forces are not "distributed". You have a fundamental misunderstanding how forces work. The force as result of the dynamic load on the 80th floor is more or less the same as on the 1st floor. In your made up physics, the higher the building, the better the forces would be distributed. Reality is different. It would not matter whether there is 1 or 80 floors below the floor where the mass falls on. The forces on the connections would be the same, given the conditions of the falling mass is the same.

.

If each tower had a mass of 250,000 tons, the first floor holds up 250,000 tons, that's a force of 2452500000 Newton.

Completely wrongalready. A floor only held its own weight and liveload. You are talking about support columns. I thought you understood this difference by now. Back to start.
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Akareyon

posted on Jun, 24 2013 @ 04:50 AM
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In your made up physics, the higher the building, the better the forces would be distributed.

Not just in my made up physics.

If you attach a 1kg weight to a spring scale, it will show 1kg (or, to be more precise, 9.81 N). If you attach that spring scale to another spring scale, both will show 9.81 N (the second one a little more for the mass of the first one). Even if you attach 100 spring scales in series, each will show 9.81 N (plus the weight of all the scales below it).

A dynamic load on a floor somewhere up high would reach the basement in less than one tenth of a second, cause displacement, shearing and buckling at the weakest points the pressure wave encounters on its way and after that not be available anymore. The higher the building, the longer the pressure wave travels, the more displacement it can cause, the less energy is available to do any harm.

Back to start.
Back to where I patiently explain that it will not help to shift the perspective from an overall description of the compression to isolating individual aspects of the collapse. While it would be easy to explain how all floor slabs were sheared off the perimeter and core columns to leave a hollow structure, it is much harder then to explain how any force could be transmitted to the core to make it fail as well. Either all the force goes into shearing the floor slabs off, or you have to do some economic gymnasics to budget some of the force for the shearing of the floor slabs and the rest of the force for the failure of the columns. Still the problem remains the same: you need a lot of built-in stress/pressure/tension to explain how the complete structure could fail. How to localize that stress in a more precise model shall be the task of those who examine the phenomenon from an engineering point of view. To me as a layman it does not matter where exactly that surplus stress was located, I have done enough to prove it must have been there from the overall physical description of the phenomenon.

Compartmentalizing the equation does not help at all, the result will still be the same: for the three towers to fail the way they did, one must assume they were planned, designed and built with enormous pre-stress exceeding its load capacity by a factor of 3, only held up by good faith, prayers and a silk thread. To not see anything unusual about it, to proclaim the process "inevitable", one must assume all - or most - tall buildings are planned, designed and built with enormous pre-stress, and this is an assumption so extraordinary it requires some extraordinary evidence.
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wmd_2008

posted on Jun, 24 2013 @ 05:24 AM
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Originally posted by FirstCasualty
So WMD and PLB believe that 15% of the structure plowed its way through the remaining 85% with - and this is in your own words - "NO RESISTANCE"

again because this is just too rich... NO RESISTANCE!!!!

And come on WMD, wth are you doing posting rubber tire fires as an example of hot fires that burn black. Do you think everyone is retarded.? and the other one? with the tankers all lying about i can only speculate what they were filled with, I suppose you are going to say they were filled with office furniture?

I am going to pretend you just grabbed the first couple pictures you saw without giving it much thought. Otherwise i have to believe you are just trying to pull the wool over everyone's eyes.

Oh and I guess the current NSA revelations have shined a little light on how something of this magnitude could be covered up.

No the whole point of the post was to show YOUR assumption that because you see black smoke
the fire was starved of oxygen was WRONG, the pictures were to SHOW that the material BURNING can dictate the colour of the smoke that SIMPLE FACT was lost on you , not only that I showed this picture.

So are you going to try and deny you see flames.

Now try and use some common sense on what items in those tower that when burned could produce black smoke

The problem with YOUR type on here is that you can ONLY concentrate on one thing at a time and can't link together what you actually see, YOU make claims re other fires care to show me another fire in a tall multi storey building of say 100+ floors were the building had a TUBE in TUBE steelframe design that the fires were started because of a plane impacting the building. Or a steel framed building STRUCK by falling debris with fires left to burn for several hours.

Also if you bother to check MOST of the other building fires used on here to try and back claims that the events of 9/11 are a CD are NOT even steel framed buildings but steel and concrete and even with those guess what you had steelwork collapse and having to be replace or even the whole building demolished.

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-PLB-

posted on Jun, 24 2013 @ 06:01 AM
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reply to post by Akareyon

1) If you want to model the tower as a spring, you first need to have a force large enough to cause displacemen to start with. The floor connections fail way before they can cause any significant vertical displacement in the columns.

2) You are arguing that it does not matter if each column on each level had to buckle, or if just the floor connections had to fail, where the exteral columns were pushed out, and the core colums collapsed as a result of the collapse of the floors instead of being part of it. Hence we saw the spires.

It does matter. So back to start.

wmd_2008

posted on Jun, 24 2013 @ 07:35 AM
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reply to post by Akareyon

Again if will ask the question based on your idea of how physics would work on the structures can you please explain why you think the South Tower shouldn't have collapsed totally, and also yet again do you honestly think the falling floor slabs and all other debris would not hit the core you have to remember the core steel section were thinner higher up the building and anything that fails and then drops joins the rest of the falling mass impacting slabs and core further down.

Akareyon

posted on Jun, 24 2013 @ 07:46 AM
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Originally posted by wmd_2008

Again if will ask the question based on your idea of how physics would work on the structures can you please explain why you think the South Tower shouldn't have collapsed totally,
Because there would be one big collision and then that's it, as usual in this universe. Or the top would break off and fall to the side. As usual in this universe. Or the whole tower would lean sideways, as usual in this universe.

Whereas falling through the rest of the structure is highly unusual in this universe and requires some unusual explanation, which has not been presented to this day.

eta: this is not to say that the inevitability theory and mini nuke theory and built-in explosive theory and SDI death star super laser ray theory are not unusual; however it should perhaps be somewhat satisfactory and valid, too.

Originally posted by -PLB-
So back to start.
...where I kindly point out that the spires also fell, therefor, an overall description is still indicated and valid.

If they fell as a result of the collapse of the floors, as you suggest, you make a leap towards the conclusion where the built-in prestress was located: as a sort of mechanism. Like, when each floor slab fell, it pulled a safety pin of sorts to initiate the collapse of the core and perimeter columns.

Seriously, what other reason would the core have to collapse? It was the spine of the whole thing, 60% of the whole weight was hanging on it. Just because the floor slabs aren't exerting any pulling force anymore, it goes "oh well, nothing to do here" and collapses as well?

You have some extraordinary explaining to do here.
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-PLB-

posted on Jun, 24 2013 @ 08:12 AM
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reply to post by Akareyon

The explanation is very simple and far from extraordinary. We have a top section including core columns, core beams and mast falling on the core beams below. If you have a hard time imagining what kind of damage that can cause then thats due to your lack of imagination. To give you some hints: the beams fail, the chaotic mass that falls pushes eveything on it way in all directions, leaving the core culumns unsupported and displaced. As a result columns buckle under their own weight (remember that formula for euler buckling you came with?), others fall over.

You can see all this happening in the videos. Why it is a mystery to you puzzles me. It seems to me you have invested too strong into the idea that something mysterious is going on and now you won't let go of that idea anymore.

IvanAstikov

posted on Jun, 24 2013 @ 08:24 AM
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reply to post by -PLB-

Can you describe how the tower's collapses would look differently, had the cores been

a) weakened at the base prior to collapse initiation.
b) weakened at the 30th floor prior to collapse initiation.
c) weakened at the 60th floor prior to collapse initiation.

Akareyon

posted on Jun, 24 2013 @ 08:29 AM
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Originally posted by -PLB-
reply to post by Akareyon

To give you some hints: the beams fail, the chaotic mass that falls pushes eveything on it way in all directions, leaving the core culumns unsupported and displaced.
You have spent your last three or four or five posts explaining that the floor connections failed long before any force could be transmitted to the core because of the huge dynamic load of the impacting mass, now suddenly you budget some of the force for the displacement of the core columns.

At least noone can say you are unable to change your mind.

And why would the core columns be left unsupported? Did they require the floor slabs to remain upright? Hardly so, more the other way round: the floor slabs were attached to the core, because the core was the "spine" of the building.

As a result columns buckle under their own weight
Why would they suddenly buckle under their own weight? They were designed to support themselves AND 60% of the live load, of course they would be able to support their own weight many times over once the live load was gone.
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-PLB-

posted on Jun, 24 2013 @ 09:09 AM
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reply to post by Akareyon

You are not reading what I write. I don't even mention floor connections. The core was supported by the core beams and the trusses. Once these have failed, you end up with unsupported columns. The mass falling down chaoticall causes horizontal displacement of the columns. You end up with unstable columns, that either fall over or buckle.

Some columns may of course have been crushed by the falling mass, but looking at the rather good condition of many of the column after collapse this seems to be a rather rare occurance.

Akareyon

posted on Jun, 24 2013 @ 01:11 PM
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Originally posted by -PLB-
The core was supported by the core beams and the trusses. Once these have failed, you end up with unsupported columns. The mass falling down chaoticall causes horizontal displacement of the columns. You end up with unstable columns, that either fall over or buckle.
I would contradict, but you do so yourself.

The core was not supported by the trusses, it's the other way round, the core held the trusses up. The floor trusses and the core were connected to each other by the floor connections. wmd_2008 has posted the schematic a zillion times by now. The trusses in turn supported the floor slabs. So once the floors failed at their weakest points, the floor connections, no force could be transferred to the core anymore. Even if with "trusses" you mean the hat truss and the two sections of the towers where the light was reflected in a funky way, they have nothing to do with keeping the core up, they just stabilize the overall structure and connect the perimeter to the core. There is no reason for the core not to be able to stand upright all by itself, trusses or not.

Because the same goes for the core beams - what reason do they have to fail? Once the floor slabs are gone, they wouldn't have any business with the collapse anymore in a scenario where the accumulated mass of the top floors rips down floor slab after floor slab, shearing them off at their weakest points, the floor connections.

Also, photographic evidence of the debris field does not support the notion of a core structure that has fallen over or down on the floors that have reached ground level first.

Your scenario makes sense only if each falling floor slab would, by falling down, pull a safety pin that connects a beam and a column or two columns so it can fall over.

Let's also not forget that there was an inner core and an outer core, adding to the stability of the "spine". So even if some floor slabs were able to rip one or two beams off the outer core columns, the highly redundant design would make sure that the core remains upright.

However, this shall be the object of an in-depth analysis by engineers with more knowledge than me. I can only do my best showing that you can twist and turn it any which direction you like and take microscopic views at telescopic realms as much as you want - sooner or later, "experts" will come to the conclusion that either the towers were designed by a genius madman with a mechanical self-destruct mode, or they were brought down with silent explosives, or by Lord Voldemort using the Death Star battlestation to reset the Matrix. Some localized damage due to a plane impact and fires, resulting in the collision of the upper section with the undamaged rest of the building alone does not explain the phenomenon of self-compression for a few simple reasons:

1.) the sum of all forces keeping the whole structure up exceeded the sum of all forces resisting the collapse progression by a factor of at least 500. That's a lever with 1 meter on one side and 500 meters on the other side.

2.) The energy input (if a free-fall drop is assumed) was scaled up by a factor of 400. That's a bomb.

3.) The domino effect and vérinage theory assume knowledge, planning, purpose - a clever, intelligent and well-lubricated mechanism, not just a crazy kamikaze pilot haphazardly crashing a plane into a bulding.

It may take another 10 or even 50 years, but by then, people will either claim they knew it all along or it was the lesser of two evils (the other one being like, the damaged skyscrapers falling on another building and setting off a domino chain reaction all the way to Central Park or so). In any case, posterity will have a good laugh from conversations like this; and first semester engineering students will be required to dissect "Mechanics Of Progressive Collapse" :-)

-PLB-

posted on Jun, 24 2013 @ 02:38 PM
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reply to post by Akareyon

You are still not reading what I say.

A top section falls on the beams and trusses, making them fail, leaving the core columns unsupported. Its that simple. There is nothing extraordinary here. On top of that the columns are pushed all around be the chaotic falling mass, making them even more unstable, maybe even pushing them over altogether.

I really don't understand what there is not to understand about this. You even claimed to understand the formula for Euler buckling. What does unsupported length mean for load capacity of columns?

wmd_2008

posted on Jun, 24 2013 @ 05:32 PM
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reply to post by Akareyon

The PROBLEM really is YOU are all theory with NO practical experience.

Here is a quote from the Portland Cement Association re progressive collapse.

Progressive collapse is a situation where local failure of a primary structural component leads to the collapse of adjoining members which, in turn, leads to additional collapse. Hence the total damage is disproportionate to the original cause.

Case in point

Skyline Plaza - Bailey's Crossroads (March 2, 1973)

From the 23rd floor to the ground care to explain why the structure did arrest the fall after all this is impossible under YOUR understanding of construction and physics.

Therefore, the trigger mechanism of the collapse was shear failure around a number of columns on the 23rd story. Without the support of these columns, other columns on that story were overstressed which ultimately led to the collapse of the entire 23rd floor slab onto the floor below. The increased loading on the 22nd floor from the weight of the collapsed floors above was too great and led to a progressive collapse all the way to the ground level

The important part in bold and underlined so it might have a chance of sinking in!!

OH just to point out one floor slab fell in this situation not 15 or 30 like the twin towers

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