Split Thread Was global collapse of WTC inevitable?

[ozeco41]

Is this going to be another thread where ergo says a rubble pile the size of the moon couldn't crush a building?

"Another"? Oh man if I had known that I wouldn't have bothered.

Suggestions for Titles please:
Heiwa 11
Son of Heiwa
Heiwa Returns

The advertising blurb leads off with "More of the same nonsense you have come to expect from..."

 

[A W Smith]

Both upper and lower sections of the building were built the same way -- except that the upper would be built of progressively lighter material, and also suffered all the fires. Point being that one is not a "block" while the other is merely "floors". They are both one or the other. Take your pick.

If one portion cannot handle the impact, then neither can the other. We see the upper block largely disintegrating. The impact it experiences (if we follow the Bazant/NIST scenario, and suspend our observation that in fact the upper block gets destroyed in mid air) is not just 15 floors on 90, but 90 floors on 15. The rubble supposedly created (and the volume that isn't ejected laterally) does not have the power to crush down the rest of the building because it is disassociated material. Sure, you could have floor failure, perhaps over several floors, but this wouldn't be able to tear down the entire building symmetrically, pulverizing all material, and at the rate of six floors per second. You would have a more organic, asymmetrical collapse where you could pretty easily see or at least tell what was happening.* You'd probably end up having floors caving in like they did in other buildings; floor assemblies hanging from the core, and you would have a much more significant core remnant that actually stayed standing and didn't disintegrate in mid-air 20 seconds after the rest.

I'm sure the rubble principle would be pretty easy to model, using a scale metal structure with a comparable height and framework with "floors" attached at both core and periphery, and dropping some debris of similar composition, or perhaps a bunch of rocks, onto the floors. See what happens to the structure.

seeing as you do not understand Newtons laws
http://ocw.mit.edu/courses/physics/...mechanics-fall-1999/video-lectures/lecture-6/

I'm almost certain you wouldn't know scaling laws
http://videolectures.net/mit801f99_lewin_lec01/

 

[ergo]

No. If you don't understand then try it this way, what was in motion and what wasn't? The entire upper block was in motion, the lower section wasn't.

No,again this is just the wrong way to think about it. Ignore the Bazant model and the destruction of the upper block for a minute and simply consider what was moving. It's the upper block that has kinetic energy, it's this energy that destroys the lower, one floor at a time. The lower section was stationary and only designed to hold the upper block when it was stationary.

If you drop a cinder block onto a stack of ten cinder blocks, what happens?

If you put a truck on auto-pilot driving at 100 mph head-on into a line of ten identical trucks parked in a line and backed by a concrete wall, what happens to the trucks?

No, we have 15 floors falling on 1 floor at a time, over and over again. 15 floors moving meeting with 1 stationary floor. Floors below the impact zone can't lend any strength to the ones being pummeled by the 15 floors in motion.

No, we don't. Look at the video. And yes they can. That is what structural integrity is. I would go into more explanation, but I'm tired of having to re-argue this every third thread.

For simplification purposes you could essentially lay out each of the lower floors and drop a 15 story section onto the first one, a 16 story onto the next and so on. That's the nature of a "cascade" failure.

You're using the Bazant model which has largely been tossed out here. And everywhere else.

It doesn't, physics unlike the human mind doesn't distinguish between shape or consistency, a pound of feathers and a pound of lead, doesn't matter.

This is patently false. No other words are necessary here.

Some rocks? lol, these are boulders, hills and mountains, not rocks.

???

I rest my case.

 

[ergo]

seeing as you do not understand Newtons laws
http://ocw.mit.edu/courses/physics/...mechanics-fall-1999/video-lectures/lecture-6/

Please explain what specifically is wrong about what I've said. Ten bucks says you won't. Maybe you should read the link yourself.

Why doesn't someone just model a rubble-driven crush down? How difficult can that be? Show us how it would work. If you can't, then maybe you shouldn't be blathering on quite so much about it.

 

[ergo]

I have repeatedly shown you step by step the simple thing you simply will not understand.

Last chance. I'll ask you a couple of very simple questions about a simple example. You answer them. By doing so, you'll understand...

1) 1 *floor* normally supports 100Kg
2) That floor WILL fail if you put 1000Kg on it.

Q) What will happen if you put 2000Kg on the floor ?

It's not that I don't understand your questions, it's that I disagree with your model and I think your questions are wrong.

 

[Sam.I.Am]

Your comparison between a building and trucks is cute... very wrong but cute all the same. Trucks are designed to protect the driver in a crash and tend to stop due to a loss of power upon a crash. Gravity never ceases.

Your cinderblock comparison is back asswards, it was more like 10 cinderblocks hitting one (and then 11 cinderblocks, then 13 cinderblo... well, you get the idea).

You really need to educate yourself on some basic physics (or don't ,but don't be surprised when people point and laugh at you because of your ignorance).

 

[Furcifer]

If you drop a cinder block onto a stack of ten cinder blocks, what happens?

The fact you would make this comparison is very telling. Could you even grasp the notion that the things we build stuff out of are stronger than the things we build? If only we could join things together at the sub-atomic level. I mean it's weak nuclear force right? Weak!

A building is made up of parts neatly put together in the most precarious of fashions. This is something you learn with practice.

If you put a truck on auto-pilot driving at 100 mph head-on into a line of ten identical trucks parked in a line and backed by a concrete wall, what happens to the trucks?

It always amounts to this, conspiracy theorists always want to translate things onto a horizontal plane. thereby taking the vertical component, GRAVITY, out of the equation.

By thinking of things on the horizontal plane you already doom yourself to failure. Relating the collapse to cars crashing is yet another way to doom yourself to failure. Again scale comes into play, as does the very simple fact that cars are designed to move and ultimately collide while in motion. And not inches per day, but miles per hour! The very thought of an entire building moving at 100 mph should be so absurd as to preclude the comparison, and yet here we are! This is as stupid as comparing fine art to punching bag to determine if it needs to be insured for damage.

No, we don't. Look at the video. And yes they can. That is what structural integrity is. I would go into more explanation, but I'm tired of having to re-argue this every third thread.

I bet it must get tiring explaining your way of seeing things! Alas, that is the problem with genius isn't it? Nobody understands you!

You're using the Bazant model which has largely been tossed out here. And everywhere else.

Really? Why please do explain how so guvnah! No seriously, cite your source for making this claim! Has "the establishment" thrown it out? Has "the man"? How about "they"? "They"'ve tossed it out right?

You are a hoot

This is patently false. No other words are necessary here.

See you don't get to say things like this without proof. More words are necessary so 'start splainin'.

You probably think what you've written amounts to an argument. It isn't. It's what we see here all the time, incredulity. You can't and won't ever produce a scientific argument because one doesn't exist. You will continue to post from a state of incredulity until you either pass on or realize how wrong you are. This is a fact, I guarantee it.

CT's are anything but original aren't they? There's such a delicious irony in the fact they come here repeating the same failed logic and call everyone else "sheep"

 

[Dave Rogers]

1) 1 *floor* normally supports 100Kg
2) That floor WILL fail if you put 1000Kg on it.

Q) What will happen if you put 2000Kg on the floor ?

Ergo has already answered this one; for some reason, he thinks it won't even fail if you put 7.35 x 10²²Kg on it.

Dave

 

[Oystein]

If you drop a cinder block onto a stack of ten cinder blocks, what happens?

If you put a truck on auto-pilot driving at 100 mph head-on into a line of ten identical trucks parked in a line and backed by a concrete wall, what happens to the trucks?...

Since we assume the trucks to rest on a more or less horizontal ground, with no constant force accelerating each and every one of them like a race car, the comparison is moot.
You should rather think of 80 trucks parked fender to fender down a 45° steep mountain slope, all of them in first gear, drive wheels spinning, and then 30 trucks crashing into the last.
You'll get a total mess.

Your comparison takes out the 500.000.000.000 Joules of kinetic energy. Your trucks compare to a building floating in space with no gravity. You are right, a building that is not subject to gravity will not collapse quite so easily.

Your trucks on a flat road can model the first story crash: Let 15 or 30 trucks crash into one. How will the one fare?

 

[Andy_Ross]

Ergo, why don't any enginees or architects with relevent experience and qualifications agree with your model?

 

[Architect]

I'm here, and I don't.

I remember explaining this at huge length to Heiwa and others. Ergo just seems to be covering exactly the same ground.

 

[sheeplesnshills]

* and by this I mean there wouldn't be nine-year-long debates going on about it. Just like there aren't nine-year-long debates about buildings that collapse from earthquakes or bombs or controlled demolition or other natural disasters. Collapses from those events follow expected modes of failure and nobody is surprised that the building behaves according to accepted principles of physics. These buildings do not and two government investigations contradicted each other about how they collapsed, and those with the technical qualifications to analyze it also disagree about the mode of collapse, with those who suggest that the government explanation is incorrect outnumbering the others.

An empiricist looks at the collapses, the observables, as Major Tom calls them, compares them to what is known about building collapses, and if there are anomalies, starts investigating those anomalies. Two government investigations have occurred about these anomalies. If there were no anomalies, why would there be investigations? The fact that there were two investigations commissioned is the recognition that the collapses did not follow expected failure patterns.

Have you ever built a house of cards? Why does it all fall down when you clumsily add the top "floor" The cards you added weigh much much less than the rest of the tower below it yet it all falls down............why?

What you have to grasp is that Mass is not equal to strength.........

 

[ergo]

A building is made up of parts neatly put together in the most precarious of fashions. This is something you learn with practice.

Preserving for sheer jaw-dropping incredibility.

 

[willhaven]

Any top driven collapse is going to arrest anyway.

What about these?

Thoughts on the Verinage technique? It involves removing the supports from a couple of floors, then using cables or hydraulic jacks to initiate collapse and letting the mass of the building and gravity do the rest of the work for you.

 

[ergo]

Since we assume the trucks to rest on a more or less horizontal ground, with no constant force accelerating each and every one of them like a race car, the comparison is moot. You should rather think of 80 trucks parked fender to fender down a 45° steep mountain slope, all of them in first gear, drive wheels spinning, and then 30 trucks crashing into the last. You'll get a total mess.

If the trucks are parked, then they're not in first gear. You describe 30 trucks hitting "the last". Are they coming from above or below? You say you'd get "a total mess". Which trucks are damaged? If you could clear this analogy up, I'd be interested in looking at it.

Your comparison takes out the 500.000.000.000 Joules of kinetic energy. Your trucks compare to a building floating in space with no gravity. You are right, a building that is not subject to gravity will not collapse quite so easily.

No they don't. My example described the third law of motion in collisions. Gravity is replaced by engine acceleration.

The impact force is caused by gravity. They are not two different forces here. Gravity was already taken care of, and then there was the impact of the upper portion slumping (if we accurately follow NIST) into the damage zone. That impact force is shared between upper and lower. Fifteen floors hit 90, and 90 floors hit 15. The lower has greater reserve strength.

 

[ergo]

Thoughts on the Verinage technique? It involves removing the supports from a couple of floors, then using cables or hydraulic jacks to initiate collapse and letting the mass of the building and gravity do the rest of the work for you.

You're a little late to the game, Will.

 

[Andy_Ross]

Preserving for sheer jaw-dropping incredibility.

Why is it incredible?

If you are designing a bridge or a building or a ships hull you don't make it any stronger than it needs to be, that would be a waste of money, time and resources. People called Engineers do things called Calculations. This lets them work out the minimum they can safely get away with under the rules and regs when they build something. Sometimes things happen to bridges, buildings and ships that are unexpected our outside their design papameters.

When this happens they fall down, collapse or sink.
When this happens there is an investigation to find the cause. Then when the next bridge, building or ship is built the Engineers doing it can take the new information into account and work out the minimum they can safely get away with under the new rules and regs.

Colin CHapman Founder and Designer of Lotus Cars used to say the perfecc racecar should fall to pieces as it crosses the finish line. Anything else was over engineering. He won lots of Grand Prix championships and Le Mans races.
What's so hard to understand?

 

[Newtons Bit]

A typical 16" long x 12" wide x 8" tall non-grouted Concrete Masonry Unit (commonly referred to as a cinderblock) has the following properties:

Net Area: 48 in²Weight = 100lb
Compressive Stress = 1500psi

The weight of one block on top of another results in a stress of 2.0833 psi. This results in a "factor of safety" of 720. Comparing this to the WTC, is quite frankly ludicrous, as modern steel buildings have a "factor of safety" of about 3 at any given section across the building.

 

[tsig]

If you drop a cinder block onto a stack of ten cinder blocks, what happens?

.

How high are you going to drop the cinder block from?

Note: cinder blocks are not steel buildings.

 

[ElMondoHummus]

Cinder blocks are also not heterogenous to the extent that buildings are, nor do they have the same sorts of points of failure as the connection points between major structural elements (such as vertical columns and floor trusses) in a tall building. And on top of that, a cinder block is not "built" in a way to where the removal of lateral bracing elements causes disarray and severe instability, as is the case in the Twin Towers where losing floors results in columns not being able to stay upright.