Tower Collapse Questions for Critical Thinkers

[jaydeehess]

This is an easy problem to solve!

We have 80 glass elements of certain mass, m, spaced 500 mm apart. How the spacing is arranged must be clarified; some sort of supports I assume, the bottom one, carrying 80 m, stronger than the top one, carrying nothing but expecting to be impacted by a bowling ball.

Inertia is the name for the tendency of an object in motion to remain in motion, or an object at rest to remain at rest, unless acted upon by a force.

Thus, the tower of 80 glass elements/supports is at rest and the bowling ball comes dropping down in motion.

What happens at impact? Well, it depends on the strength of the top glass element and the bowling ball - the two elements in contact only! If the top element at rest is reinforced, armored glass and doesn't break, it will transmit forces on the supports below and on the bowling ball. The bowling ball may actually break or bounce or one or more supports below.

As we say: You have to start at the top to get things changed in a structure (or organisation).

In the example above, the 79 glass elements below the top one have not got a clue what the top glass element and bowling ball are up to, when they meet.

If this situation is supposed to be analogous to the WTC towers at all then it has to be the glass itself that supports the legs laterally. That is to say that the glass is connected directly to the legs which in turn keeps the legs vertical which in turn allows the structure to remain upright.

Let's assume that the legs are each a continuous column with welded on glass floor seats and bolts or rivets holding the glass to the seats.

The mass hitting the next glass 'floor' is increased by the mass of broken glass from the floors above it.

Will the floors eventually arrest the fall?

Not if the falling mass exceeds the load capacity of the glass and in the case of the towers the mass that was hitting the floors far exceeded even the static load that an individual floor was designed to hold. So in our analogy one would have a bowling ball of sufficient mass that even if it were simply and carefully placed on the glass 'floor' that 'floor' would crack and fail. Note that this is not to say that the legs would not be able to support such a mass. In fact the whole purpose of the legs is to take the mass loading of the entire structure above any height whereas the floors need only support the mass expected on any individual floorspace

Add in any dynamic loading at all, much less any additional mass loading of falling glass, and the collapse through the glass floors will acellerate, not decellerate.

As the floors break away in this analogy the legs will be increasingly long unbraced columns. They will bend due to their inherent instability and may actually buckle before the last 'floor' fails. At any rate they will fall over when the last 'floor' fails.

 

[Dave Rogers]

Let's just look at an example of a falling body taking the path of least resistance, shall we? I've used this one before, but I'd like to hear kylebisme's thoughts on it.

Put an egg on a horizontal slab of concrete. Suspend a brick a foot above the egg. Now, it's fairly obvious, isn't it, that the path of least resistance is through the air around the egg, and the path of most resistance requires the brick to crush the egg?

Now drop the brick. It didn't take the path of least resistance, did it?

You may argue that there was nothing to move the brick sideways, so it couldn't possibly miss the egg. That's exactly the point. Falling objects do not seek out the path of least resistance, as this simple experiment clearly demonstrates. They accelerate in response to the forces exerted on them, and if there is no force that can accelerate them towards some hypothetical path of least resistance, they do not take that path.

In this context, and in that of the collapse of the Twin Towers, "path of least resistance" is an irrelevant concept.

Dave

 

[Heiwa]

If this situation is supposed to be analogous to the WTC towers at all then it has to be the glass itself that supports the legs laterally. That is to say that the glass is connected directly to the legs which in turn keeps the legs vertical which in turn allows the structure to remain upright.

Let's assume that the legs are each a continuous column with welded on glass floor seats and bolts or rivets holding the glass to the seats.

The mass hitting the next glass 'floor' is increased by the mass of broken glass from the floors above it.

Will the floors eventually arrest the fall?

Not if the falling mass exceeds the load capacity of the glass and in the case of the towers the mass that was hitting the floors far exceeded even the static load that an individual floor was designed to hold. So in our analogy one would have a bowling ball of sufficient mass that even if it were simply and carefully placed on the glass 'floor' that 'floor' would crack and fail. Note that this is not to say that the legs would not be able to support such a mass. In fact the whole purpose of the legs is to take the mass loading of the entire structure above any height whereas the floors need only support the mass expected on any individual floorspace

Add in any dynamic loading at all, much less any additional mass loading of falling glass, and the collapse through the glass floors will acellerate, not decellerate.

As the floors break away in this analogy the legs will be increasingly long unbraced columns. They will bend due to their inherent instability and may actually buckle before the last 'floor' fails. At any rate they will fall over when the last 'floor' fails.

The damage analysis problem was a bowling ball C contacting the glass top (A80) of a table on top of 79 other glass top tables (A1-A79). It looks similar to the WTC 2 destruction.

Question is what happens, when C impacts A80 glass top.

One possibility is that C breaks glass top A80, which requires energy to be established (C loses speed = decelerate), and that C then continues to try to break glass top A79 (C loses speed again, etc, etc). Broken pieces of A80 may assist C in this venture.

Another possibility is that (reinforced, strong) glass top A80 breaks C! A80 arrests C.

A third possibility is that neither glass top A80 nor C break (they only suffer local deformation) and the result will then be that C bounces on A80 (assisted by ground and A1-A79) and then stops on A80 after some more bounces. Again A80 + structure/tables below arrest C.

So it seems there are two possibilites of A80 arresting C and only one possibility that C breaks A80.

NIST has evidently not investigated the former possibilites, when they study the WTC destructions, so its analysis is incomplete, to say the least.

I am amazed that NIST does not know how to do proper structural damage analysis.

 

[stateofgrace]

I am amazed that NIST does not know how to do proper structural damage analysis.

What is amazing is that a lying fraud honestly thinks he is in position to criticize anybody.

The same lying fraud who runs from threads and the same lying fraud who makes wild claims and runs away like a little child when called out on them.

You are not in any position of authority to criticize nor have you any moral high ground to do so, fraud.

 

[BasqueArch]

Originally Posted by kylebisme
Ah, yeah, they were mentioned to me in a PM by another member erlier as "the French demos", I simply wasn't familiar with the term "verinage". Anyway, the videos you posted do show an unsual form of controlled demolition, using cables to pull out supporting structure rather than explosives to blast it out. Furthermore, note how the velocity of the upper mass decreases after coming into contact with the lower mass, demonstrating the resistance provided by that lower mass. Also consider how much more the deceleration would have been had that lower structure been not simply concrete but rather also framed with steel.

ah... so now you are going to Tony S's missing jolt?

really?

that is highly amusing.

shift shift shift.

Do you know what else it shows? That Bazant was right, and BLGL fully explains what happened to the towers...

The verinage demos seen are of concrete load bearing walls and thick reinforced concrete floor structures, not post-and-beam columns with weak floor topping structures. When the upper two stories are pushed sideways the floors fall onto the undisturbed relatively large load bearing area concrete walls and floors below, thereby the "jolt".

The exterior columns of the TTs were buckled inward and the columns of the 10-23 upper stories fell eccentrically onto the fire damaged 4", 2.5" at the pan ribs lightweight concrete floor below, not axially onto the columns below.

The thin damaged floors could not meaningfully arrest the columns of the upper 10-23 stories from crushing the floors below, therefore no "jolt".

Tony S's hypothesis of the "missing jolt" corroborates the recorded visual facts seen of a gravity only driven collapse.

 

[Heiwa]

What is amazing is that a lying fraud honestly thinks he is in position to criticize anybody.

The same lying fraud who runs from threads and the same lying fraud who makes wild claims and runs away like a little child when called out on them.

You are not in any position of authority to criticize nor have you any moral high ground to do so, fraud.

LOL.

I just outline the basics of structural damage analyzis. It seems the real lying frauds are at NIST!

 

[stateofgrace]

LOL.

I just outline the basics of structural damage analyzis. It seems the real lying frauds are at NIST!

Stop lying; you have never produced any structural analysis worth anything. Simply repeating over and over again one lemon cannot crush nine other lemons or one Lego block cannot crush nine others is not structural analysis, my nine year daughter figured that one out, genius. YOU have to show the exact relationship between all the support elements within the WTCs and proof by maths how each element reacts and stops the collapse.

And NIST are not accountable to an insignificant fraud like you.

Also start backing up your unwarranted bravo and get your fraudulent butt over to the threads that you are avoiding and prove me wrong. You know the ones.

 

[jaydeehess]

The damage analysis problem was a bowling ball C contacting the glass top (A80) of a table on top of 79 other glass top tables (A1-A79). It looks similar to the WTC 2 destruction.

then you go on as if that was not the problem that was to be investigated. Why is that?

Question is what happens, when C impacts A80 glass top.

One possibility is that C breaks glass top A80, which requires energy to be established (C loses speed = decelerate), and that C then continues to try to break glass top A79 (C loses speed again, etc, etc). Broken pieces of A80 may assist C in this venture.

Another possibility is that (reinforced, strong) glass top A80 breaks C! A80 arrests C.

A third possibility is that neither glass top A80 nor C break (they only suffer local deformation) and the result will then be that C bounces on A80 (assisted by ground and A1-A79) and then stops on A80 after some more bounces. Again A80 + structure/tables below arrest C.

So it seems there are two possibilites of A80 arresting C and only one possibility that C breaks A80.

Once again then if the dropping mass on the glass floor would be sufficient to break the glas even if it were simply and carefully placed on the glass then there is no need to investigate further. Given that this was the case in the WTC towers it would be rather a useless expense to go any further along that line.

NIST has evidently not investigated the former possibilites, when they study the WTC destructions, so its analysis is incomplete, to say the least.

I am amazed that NIST does not know how to do proper structural damage analysis.

I, and so many others, are amazed that you simply are utterly incapable of admitting that a floor could not support anything close to the mass that was impacting them in the collapses let alone the dynamic and chaotic loading involved.

You have completely ignored my previous post while pretending to have addressed it. Interesting.

 

[jaydeehess]

One possibility is that C breaks glass top A80, which requires energy to be established (C loses speed = decelerate), and that C then continues to try to break glass top A79 (C loses speed again, etc, etc). Broken pieces of A80 may assist C in this venture.

BTW H, you forgot to account for the increase in velocity between floor hits.

 

[Heiwa]

Once again then if the dropping mass on the glass floor would be sufficient to break the glas even if it were simply and carefully placed on the glass then there is no need to investigate further. Given that this was the case in the WTC towers it would be rather a useless expense to go any further along that line.

It is the energy applied by the dropping mass that may break the glass. If the glass breaks, energy has been used, and one result is that the dropping mass decelerates (it has lost kinetic energy).
Then there is real need to investigate further, e.g. how much energy was used to break the glass, how much energy is still avalable to break further glass, etc.
With regard to WTC 1 the dropping mass, let's call it C, could only apply say 1.2 GJ of energy at impact with mass at rest, let's call it A, and as C and A are virtually identical structures at contact interface (no bowling ball C contacting glass A), the energy is applied 50/50 to A and C ... and the energy will start deforming elements in both C and A, which may cause some elements in C and A to break. Evidently the weaker elements break first in contact with stronger elements, e.g. columns will break floors, and then energy applied is transformed into heat.
And that's what should have happened with WTC 1 - only the bottom floor of C and the top floor of A would get damaged.
But as you need much more than 1.2GJ to damage these floors, the destruction due to a drop would stop at once!! Only local failures to the two floors in contact (and adjacent columns) would take place.

Evidently you do not see that on videos of the 911 WTC destructions. First you see upper mass C being blown apart (only debris of C is then falling) and then lower mass A is blown apart, step by step, from top down creating a fountain of debris, concrete dust (the floors are blown apart), big perimeter wall panel sections 10 floors high are blown away sideways, and smoke.

Sorry, dropping little C on big A cannot possibly create such a destruction! So the WTC 911 destructions are some sort of controlled demolitions using energy other than that of gravity acting on dropping mass(es).

 

[psikeyhackr]

However the analogy quickly breaks down given that in a complex piece of equipment several ciruits fed from the same power supply will have different curents than others. If the electrons were required to flow in the path of least resistance then current would be flowing in only one of those circuits.

It would suck for any parallel circuitry

.
So the most current takes the path of least resistance in a parallel circuit. But structural engineering doesn't deal with things as small and fast as electrons. The falling material can't make 90 degree turns at 90% of light speed.

psik

 

[funk de fino]

.
So the most current takes the path of least resistance in a parallel circuit. But structural engineering doesn't deal with things as small and fast as electrons. The falling material can't make 90 degree turns at 90% of light speed.

psik

Then why do your lot bring it up then?

 

[PixyMisa]

It is the energy applied by the dropping mass that may break the glass. If the glass breaks, energy has been used, and one result is that the dropping mass decelerates (it has lost kinetic energy).
Then there is real need to investigate further, e.g. how much energy was used to break the glass, how much energy is still avalable to break further glass, etc.
With regard to WTC 1 the dropping mass, let's call it C, could only apply say 1.2 GJ of energy at impact with mass at rest, let's call it A, and as C and A are virtually identical structures at contact interface (no bowling ball C contacting glass A), the energy is applied 50/50 to A and C ... and the energy will start deforming elements in both C and A, which may cause some elements in C and A to break. Evidently the weaker elements break first in contact with stronger elements, e.g. columns will break floors, and then energy applied is transformed into heat.
And that's what should have happened with WTC 1 - only the bottom floor of C and the top floor of A would get damaged.

No. Completely wrong. (And completely absurd.)

Take that tower of glass tables example. Let's say each table weighs twenty pounds. The glass surface weighs ten pounds and can support twenty pounds in weight, total, so it holds itself up just fine. The legs of the table weigh another ten pounds in total, and are solid steel, so they can support two thousand pounds in weight.

You can stack fifty of these tables up so long as you carefully position them so that the legs of each table are directly above the legs of the one below. And you can add up to ten pounds of weight to each and every one of the tables and it will still stay up.

But if you put a twenty-pound weight on one of the tables, it will break, and drop thirty pounds of weight on the table below (more if the legs fall inwards) which will break and drop forty pounds of weight on the table below that. Stack fifty tables up and you have a nice, solid, secure tower. Take the top table - weighing only twenty pounds - turn it at an angle, and drop it from even one inch, and the entire structure, easily capable of holding five hundred pounds of weight, disintegrates.

 

[Architect]

LOL.

I just outline the basics of structural damage analyzis. It seems the real lying frauds are at NIST!

No, you are: I refer you to your spurious claims regarding Ronan Point.

 

[Justin39640]

.
So the most current takes the path of least resistance in a parallel circuit. But structural engineering doesn't deal with things as small and fast as electrons. The falling material can't make 90 degree turns at 90% of light speed.

psik

structural engineering never ever deals with the crystalline structure of metal and its atomic make-up? hmmmm

the circuit draws as much current as it needs
hence why your lightbulbs dont explode every time you turn them on lol
just cause you have a power supply that can deliver 500 amps doesnt mean that youre gonna draw all 500 through the different paths of the circuit
IIRC when youre trying to understand how many amps it will draw the power formula comes into play along with ohm's law (if youre trying to size your supply)

IDK a whole lot about this stuff (and im sure im not 100% correct), just enough to fix it
but from what i understand the flow of a valance electron from one atom to the next is kind of a smooth transition not a 90 degree angle
and seeing even on the tiniest of printed circuit tracks its still thousands (modest) of atoms wide i dont think electrons take too many hard lefts like youre implying

so i take it then that youre saying thew towers should have fell strait down like they did
thanks

 

[BasqueArch]

......
And that's what should have happened with WTC 1 - only the bottom floor of C and the top floor of A would get damaged.
But as you need much more than 1.2GJ to damage these floors, the destruction due to a drop would stop at once!! Only local failures to the two floors in contact (and adjacent columns) would take place.

Evidently you do not see that on videos of the 911 WTC destructions. First you see upper mass C being blown apart (only debris of C is then falling) and then lower mass A is blown apart, step by step, from top down creating a fountain of debris, concrete dust (the floors are blown apart), big perimeter wall panel sections 10 floors high are blown away sideways, and smoke.

Sorry, dropping little C on big A cannot possibly create such a destruction! So the WTC 911 destructions are some sort of controlled demolitions using energy other than that of gravity acting on dropping mass(es).

And you propose these enormous forces created by a handful of 1kg charges placed at the core columns:

Heiwa
Well, say you need an average 1 kg powerful energetic device to cut apart an outer core column and that you have to cut 24 outer core columns to initiate the destruction - upper part moving down a little by gravity producing local structural failures elsewhere in, e.g. outer walls - then you only need 24 kgs of powerful energetic devices on one floor to start the show. Hm, it can be carried in one or two bags or one box! Easy to carry.

Say you find that you have the prepare every third floor in a similar way to produce a top down controlled demolition and that you rig total 30 floors to carry out the destruction then, lets see; 30 times 24 is 720.

So it seems 720 kgs of energetic devices are required.

Salma Hayek's unanswered response

Salma: “That’s better, I was beginning to think your friends were interested in my superficial temporal shell only, not my brains! Hand me the calculator sweetie I have some questions...

One. *Click, click, click ...* ( 208 perimeter feet x 4sides x 12 feet high per story x 110 stories / 1584#explosives = 1# explosives per 693 sf of perimeter columns area 35 to 60 feet away. And, 4.7MM sf floor area / 1584# explosives = 1# explosives per 2,967 sf of concrete floor area 18 vertical and 35 to 60 horizontal feet away, ) . And don't shaped charges concentrate their force in a small area and in one direction only?

So the mariner then agrees that 1kg of explosives could not have caused 4 ton perimeter columns to have been propelled horizontally 600 feet like the physics teacher claims, nor the complete pulverization of 4.7 million sf of concrete floors like many others claim. Does the mariner know that?

Two: And don’t recorded video facts show, in places, exterior core columns intact 40 and 60 stories high? Then explosives could not have been placed there!

Three: And wouldn't the exterior columns have been pulled in towards the core of the building and not toppled outwards, unattached to floors, like the recorded video facts show? Then explosives could not have been placed there!"

You can run away from Salma but you'll only die tired.


-----------------------------------------------------------------------
You can't reason someone out of something they were never resoned into

 

[kylebisme]

A principle that does not apply to collisions or collapses.

Perhaps you have seen others argue that the principle of least resistance applies to collisions and collapses in some way which it has doesn't, and seen such people thoroughly refuted. I am not any of those people though, and I am not making any such arguments here. I am talking about a well established principle which applies to all matter in all situations. To address the case of collisions specifically, I'll quote a doctor describing how this principle is observed in the fracturing of bones:

And as we all remember from high school physics, force takes the path of least resistance, which in this case means the fracture is most likely to occur through the growing part of the bone.

To speak in far more general terms, I'll quote a physicist discussing how the path of least resistance confirms Einstein's General Relativity as providing a more accurate representation of observable reality than Newtonian physics:

This is the modern model for the force of gravity. Objects follow a path of least resistance through space-time, and the path is curved when space-time is distorted.

So, please, do not conflate what I have been saying here with the absurd Idea that the top of the towers should have simply slipped off the side without crushing anything. I have not, and would not, make any such claim; and miss assuming such arguments upon me to dismiss what I have said by dying well established an consistently demontarted principles of physics does nothing to further the course of rational discussion.

Or you could read the Wiki "current divider" article, which correctly lays out the math.

As the Wiki article you link states:

This is because in current dividers, total energy expended is minimized, resulting in currents that go through paths of least impedance, therefore the inverse relationship with impedance.

Of course you could have also looked up path of least resistance, which metions how the principle applies to both mass and electricty, as I have been saying here:

In physics, the path of least resistance is always taken by objects moving through a system. For example, water flowing downhill follows the path of least resistance as it is pulled downward by gravity. Electricity flowing through a circuit behaves similarly; while every available path has some current flowing through it, the amount of current through each path is inversely proportional to its electrical resistance.

While you may have semantic dispute with my phrasing, I hope you realise that I am talking about the behavior of electricity as represented in Ohm's Law.

Simply put, the ratio of the currents in two parallel circuit branches will be equal to the inverse of the ratio of their individual impedances.

Simply put; assuming two paths of different impedance, though which path does the majority of the current flow? I am guessing you can answer that question correctly, but as at loss as to why you refuse to see that I am using the phrase "the path of least resistance" to refer to that answer.

 

[funk de fino]

While you may have semantic dispute with my phrasing, I hope you realise that I am talking about the behavior of electricity as represented in Ohm's Law..

Nope, you are not

 

[HeyLeroy]

Typical Truther thread.

Truther asks leading, semi-incoherent question.

I try to figure out what is being asked and provide answers.

Argument continues, unabated. I have no idea what is being asked now, or where it's going. If the question that's really behind this is "why didn't the upper block topple off," it's because it can't. The maximum rotation seen at any point of collapse was about 26 degrees, and most of this happened as a free body, rotating around its center of gravity. The dimensions of the upper block are such that it would have taken almost 40 degrees of rotation before becoming a free body to move its center of gravity outside the footprint. In reality, it only rotated about ten degrees before coming loose. After it's loose, it cannot experience a "fulcrum"-like behavior, because there is no fulcrum. At that point, there is actually a restoring force exerted by the lower structure, not a continued torque towards rotating and toppling off.

Draw a free-body diagram if you don't believe me.


I covered this in great depth in my whitepaper, pp. 104-105 and 250-255. It's been out in the current draft for sixteen months or so.

The problem with the Truth Movement, as always, is that when it "asks questions and demands answers," the questions it asks are leading questions, and it is not intelligent enough to comprehend the answers.

And the VERY NEXT POST:

OMG, intelligent questions. I feel faint.

This presents the problem of relating what should have happened to what did happen.

I think Richard Gage said the top tilted at 22 degrees at his show I attended in 2008. I recently saw some site that said 23 degrees. It certainly looks like more than 15 to me.

As to what should have happened. More weight should have been put on one side of the building and greatly overloaded that side crushing it more quickly which would then have caused the top to tilt more until the center of gravity was beyond the edge of the building. It then should have fallen down the side.

Evidence? References?

The fact that what did happen was so different from what should have happened demonstrates that other forces were involved in removing the resistance of the lower portion of the building.

(snip)

psik

I'll wait for your evidence before agreeing with you.

.
You call this VERY SLOW?

http://www.youtube.com/watch?v=9SSS0DDqfm0

Between five and six seconds into the video you can see the restoring force of which R.Mackey spoke. Pay attention to the columns toward the right of the screen, before they're enveloped in smoke. The counter-clockwise rotation stops, and the columns exhibit (for a second before they're obscured) a clockwise rotation.

 

[Heiwa]

No. Completely wrong. (And completely absurd.)

Take that tower of glass tables example. Let's say each table weighs twenty pounds. The glass surface weighs ten pounds and can support twenty pounds in weight, total, so it holds itself up just fine. The legs of the table weigh another ten pounds in total, and are solid steel, so they can support two thousand pounds in weight.

You can stack fifty of these tables up so long as you carefully position them so that the legs of each table are directly above the legs of the one below. And you can add up to ten pounds of weight to each and every one of the tables and it will still stay up.

But if you put a twenty-pound weight on one of the tables, it will break, and drop thirty pounds of weight on the table below (more if the legs fall inwards) which will break and drop forty pounds of weight on the table below that. Stack fifty tables up and you have a nice, solid, secure tower. Take the top table - weighing only twenty pounds - turn it at an angle, and drop it from even one inch, and the entire structure, easily capable of holding five hundred pounds of weight, disintegrates.

LOL! Original structure was 80 tables - not 50 - stacked on top of each other and each table had very strong legs as you point out. They could carry 2000 lb.

But this table tower (legs/glass tops) is very easy to topple as the tables are not really connected with one another. Just stacked on top of each other. Lateral strength of table tower is zero.

So result would be 80 broken glass tops and all table legs, strong, intact. No table leg will be broken. Like a house of cards! The cards are not broken. Just displaced.

You really don't know anything about structural damage analysis, I am sorry to conclude.