David Chandler jumps the shark

[jaydeehess]

In the least case - holding them in contact - no relative motion - then releasing your support so the load is instantaneously applied - it is DOUBLE. Increases rapidly if you drop it - any situation where it impacts with velocity.

Kind of the entire raison d'etre of a pile driver.

Nail gun
Stapler

 

[Notconvinced]

Here's a thought experiment. Let's say an M1A1 tank was assembled on the 78th floor. Then a trap door under it release and the tank drops onto the 77th floor. Assuming it smashes through the 77th, will it stop before it gets to ground level(or basement)

If it gets through the 77th floor, and all subsequent floors are identical, no... I think it would fall to the ground. The difference is, it doesn't pull each floor down with it, and it certainly doesn't pull the building envelope as well.

 

[beachnut]

If it gets through the 77th floor, and all subsequent floors are identical, no... I think it would fall to the ground. The difference is, it doesn't pull each floor down with it, and it certainly doesn't pull the building envelope as well.

got some math to go with the BS? No

Let's ask this question... does the verinage technique ignore gravity? Why does it work?

I'm not ignoring gravity, I'm noting that it has been in play all along, and the strength of the construction already overcame the force of g on those members. You folks want to instantly liberate PE for an entire floor (my definition here, not yours) without accounting for the KE required to do so and the consequential loss in v, which reduces p for the falling mass. There is no build up in m from new floor compaction because the floor is crushed on an axis which already carried it, so what you get is a net depleting KE.

Just to play devil's advocate, let's say your falling mass did somehow manage to bypass all of the structural members who had worked against g, and you did liberate a (your definition here) - "floor". In that scenario all of those bypassed static structural members would have destroyed the falling block like stakes through the heart of a falling vampire. It would have been broken to bits and the structural lattice would have nested into a reciprocal version of itself below it.

LOL, make believe physics. 911 truth's best skill, fantasy, BS, lies, and nonsense.

Does 911 truth make this BS without help, or do they copy and paste this from 911 truth playbook of woo?

Why do 911 truth followers mock the murder of thousands by 19 terrorists with lies and BS physics? Why do 911 truth followers apologize for 19 terrorists?


Going for the Pulitzer yet? no, 911 truth has no evidence

 

[Notconvinced]

Another thought experiment:
In the pristine building on Sept 10, 2001 all furnishings, office and building support equipment, internal pipes and fixtures, and staff were removed from every floor above the 98th and stacked on the 98th floor. Going to be a bit tight but let's let the people move and mingle about on the 98th as well.

Can this be accomplished without the 98th floor span breaking loose from its connections to the core and perimeter columns? 12 times normal loading.

If so what if we also disassemble the core columns and hat truss above 98 and stack them on the 98th?(toss perimeter columns off the side)

There is little to no dynamic impact going on and everything is loose unconnected components stacked on the floor.

Thought experiments are fun...

I think the floor span would give way. I don't think it fair to toss those poor perimeter columns off to the side however, after all they form an inherently self sufficient tube. Perhaps they should hang around and see what happens... witnesses are a good thing.

Also, was that explosives or incendiaries that were used to disassemble the core columns? I couldn't quite tell over the screaming of all those dying people.

So as I see your experiment playing out now... we have a tube of perimeter columns going "why did you do that???"

 

[beachnut]

Thought experiments are fun...

I think the floor span would give way. I don't think it fair to toss those poor perimeter columns off to the side however, after all they form an inherently self sufficient tube. Perhaps they should hang around and see what happens... witnesses are a good thing.

Also, was that explosives or incendiaries that were used to disassemble the core columns? I couldn't quite tell over the screaming of all those dying people.

So as I see your experiment playing out now... we have a tube of perimeter columns going "why did you do that???"

Mocking the murder of thousands with BS, fantasy, and dumbed down lies.

Can you explain the failed physics?

No
1/2 ((14/15)m₁(14/15)v₁))²=KE
Really??

Proof physics is prohibited in 911 truth.
What are the units? Any clue yet?

 

[ozeco41]

Here's a thought experiment. Let's say an M1A1 tank was assembled on the 78th floor. Then a trap door under it release and the tank drops onto the 77th floor.¹ Assuming it smashes through the 77th² , will it stop before it gets to ground level(or basement)³

Let me caution against partial analogies linked to the real WTC Tower setting.

With that disclaimer:
1 ) I'm OK with the setup down to this stage.

2 The assumption is probably wrong. There would not be a clear "Wile E Coyote" tank shaped hole cut cleanly through. The real result would be that the floor slab would break up - joists and pan break or bend and an area larger than the tank would get pushed down to the next level. Almost certainly it would tear the floor joists off the perimeter and core columns in preference to shearing the floor near the perimeter off the tank. (It is the same engineering logic as my other comments on "vampire stakes" - the connections to the columns are weaker in shear than the floor deck and joists.). So the falling tank now has a larger than tank "sheet anchor". It may break similarly through the next level BUT the "sheet anchor" would tend to plug the hole in that next floor - wedging the tank in place.

Then it becomes a race between "dragging more sheet anchors" and "sheet anchors being shear abraded and left behind in tatters". I'm engineer gut feeling judging (AKA "guessing" ) that "tatters" doesn't happen.

My money on arrest at 2nd, 3rd or 4th floor down.

3 Yes! in the real scene. No! if you continue with the "Wile E Coyote" version.

 

[ozeco41]

Another thought experiment:
In the pristine building on Sept 10, 2001 all furnishings, office and building support equipment, internal pipes and fixtures, and staff were removed from every floor above the 98th and stacked on the 98th floor. Going to be a bit tight but let's let the people move and mingle about on the 98th as well.

Can this be accomplished without the 98th floor span breaking loose from its connections to the core and perimeter columns? 12 times normal loading.

If so what if we also disassemble the core columns and hat truss above 98 and stack them on the 98th?(toss perimeter columns off the side)

There is little to no dynamic impact going on and everything is loose unconnected components stacked on the floor.

the problem would be putting it into practice.

It would not be practical to uniformly distribute putting the overload in situ so that all parts of the floor are incrementally loaded in lock step.

So in practice some bits would be loaded more than adjacent bits. And it could well survive with statically placed loads at 12 times in selected areas only. BUT once it triggered and failed at that location the rest would follow suit in zip fastener style.

 

[Dave Rogers]

Diminishing return... Each iteration of impact yields less and less destruction.

Only if you neglect the potential energy released by the falling mass. So your argument is, and has always been, that if you neglect the energy source driving the collapse then there is no energy source to drive the collapse.

Dave

 

[Dave Rogers]

Again, nobody is contesting that. When you say "floor" you mean literally just the flat span of poured concrete and truss that people walk upon. When I say "floor" I mean the entirety of the space that the elevator moves through from level to level, thus including the exterior and interior support columns which your side like to pretend didn't exist.

Ironic, since in effect you're claiming that the support columns are a continuous medium that supports the falling mass even after failing. You're treating the towers as solid masses when it suits you to do so, then complaining that everyone else is describing them unrealistically.

Looking at the real structure, rather than the gravity-free, homogeneous and mass non-conserving abomination you've conjured up, most of the space between floor slabs is just air. When support columns fail, anything they are carrying falls through that space, rather than continuing to be supported by the columns as you've inexplicably claimed; the columns buckle and fall themselves. As they fall, potential energy is converted into kinetic energy, and the key finding of Bazant's original paper is that, whatever the mechanism, for a structure of the WTC towers's strength to weight ratio, the rate at which potential energy is released is far greater than the rate at which it's absorbed by the failure of the structure. And this is true also in verinage demolitions, building implosions and any other collapse mechanism you can imagine. The WTC towers were metastable, and that's why they continued to collapse once they started.

And further evidence for this is available from the laughable nonsense that has to be invoked by anyone and everyone who tries to pretend it isn't true.

Dave

 

[GlennB]

I said you lose KE. The lower KE then has to drive it's way through additional resistance while at the same time depleting itself of the equivalent KE. If one story below is crushed, then one story above is crushed, and in that crushing, their net KE is zero.

Perhaps this is where you're going wrong, Notconvinced? Are you conflating Newton's "action and reaction are opposite and equal" with the KE of the falling mass, and supposing that the "KEs" of impacting and impacted floors must be opposite and equal?

KE is a scalar quantity - it has no direction. The (originally) static impacted floor has zero KE in these terms. If the KE of the impacting mass is sufficient to break the impacted floor then the collapse continues down to the next impacted floor and a whole new dose of KE is added to the calculations. Greater KE, in fact, as the mass of the falling body is now greater and the KE that broke the original impacted floor was not totally expended.

 

[tsig]

I never said 9 volts couldn't be green.......

Electricity is white.

(at least 480 vac applied directly to the forehead looks white)

 

[tsig]

Why can't you explain this massive silly physics play?


Explain this super secret physics stuff.

When can you explain how you made up the silly physics stuff?

Got a name for your units? Got a source?

The units are scalar thereby proving Godzilla did the buildings.

 

[GlennB]

The units are scalar thereby proving Godzilla did the buildings.

You're covering up for Mothra, aren't you.

 

[Myriad]

Unlike you treasonous D-bags, I actually work with antimatter and am quite aware of it's 1022kev energy release.

You make me wonder why I've ever thrown the 'pardon' word around.

The kinetic energy is lost in heat and deformation. As your dynamic forces deplete, you're left with the same structural loads that the towers carried for 30+ years.

Clearly you folks are being deliberately obtuse.


Sent from our shared looking glass platform

The problem you have isn't that your arguments are wrong. They are, but that isn't the problem.

The problem is that as things stand, you can't convince anyone important using wrong arguments.

Threats such as those implied by your talk of denying "pardon" are one approach for accomplishing the latter. History demonstrates that it's possible to get people to agree with all kinds of obviously wrong things under threat of imprisonment, torture, execution, forfeiture of assets, and the like. (Most of the people who were making and enforcing those threats seem to have thought, from their through-the-looking-glass perspective, that they were right, and that that justified the threats. But of course they were wrong, and could only get people to agree by force.)

For that to work, the threats must be credible. Yours aren't.

You might try, instead, a long-term movement to denounce physics as an outmoded imperialist racist construct of the white patriarchy. That approach seems to be working in other areas of public politics in the U.S. I can't guarantee success, though.

 

[Oystein]

...
Why can't you tell anyone how much energy, in joules, was used up in heat and deformation.

How much of the 115 Tons of TNT in energy, E=mgh released, was used up by deformation and heat?

Do you do math?

With 576,210,000,000 joules released in each tower, due to fire, what was used up for deformation and heat?
...

Beachy beachy, are you being deliberately obtuse? Don't you know that "tons of TNT" or "Joules" a the D-baggy way of expressing energy?

Learn from notconvinced! You need to express this in keV!

It's 3,601,312,000,000,000,000,000,000,000 keV

 

[Oystein]

Again, nobody is contesting that. When you say "floor" you mean literally just the flat span of poured concrete and truss that people walk upon. When I say "floor" I mean the entirety of the space that the elevator moves through from level to level, thus including the exterior and interior support columns which your side like to pretend didn't exist. The "floor" that resists and diminishes the momentum of the falling floor above it includes all of those features, the stairwells, the machinery, the articles, etc.

If I actually believed you could somehow consolidate all of the upper tower's momentum onto weak floor joints while miraculously bypassing the outer box columns, stairwells, inner columns, etc we wouldn't be having this discussion.

Ok, just a little explanation for you:

The total floor area was 63 x 63 meters = 3969 m² (give or take a few % as I am "cutting cornes" by working with rounded numbers and assuming a perfectly square area).
The 240 perimeter columns (or 236? again, a few % don't matter at this point) were 14x14 inches, thus occupying roughly 30 m² in sum. The 47 core columns were thicker but fewer, I'd guess they occupied about the same area, or perhaps a bit more - let's be generous and say 50 m².
Add spandrels as parts of the external columns - 5/8 inches thick, IIRC, and accounting for about 2/3 of the circumference (4 x 63 m), they add under 3 m².

So roughly 83 m² of the total floor area were columns - that's 2% - and the remaining 98% were flat floors or core beams.
It would follow that up to 98% of the falling mass that is not outside of the perimeter would impact floors or beams, and not columns directly.

Are you with me so far?

 

[jaydeehess]

Thought experiments are fun...

I think the floor span would give way. I don't think it fair to toss those poor perimeter columns off to the side however, after all they form an inherently self sufficient tube. Perhaps they should hang around and see what happens... witnesses are a good thing.

Also, was that explosives or incendiaries that were used to disassemble the core columns? I couldn't quite tell over the screaming of all those dying people.

So as I see your experiment playing out now... we have a tube of perimeter columns going "why did you do that???"

The TE involves moving items above the 98th floor. Why would you assume I meant toss all perimeter columns for 110 floors off to the side?

This goes to the progressive collapse following the collapse initiation stage. You note that even though no significant dynamic forces are generated, even though every component above 98 is now simply debris, that the floor will give way. Above you noticed that the tank would fall all the way to the ground in the other TE.)
So it can be seen that in the actual collapse that if forces are directed primarily on floor spans then the falling mass will continue to strip floors off their connections to core and perimeter.
The perimeter tube could not stand on its own even if the rest of the building magically disappeaed let alone do so in the event of violent removal of that internal structure( core isn't even attached to perimeter as a result of progressive floor span Destruction)
Core structure also could not have stood for long by its lonesome. However it too was being smacked hard by falling debris. It's no great wonder that only a short lived remnant remained as the dust cleared.

 

[jaydeehess]

Let me caution against partial analogies linked to the real WTC Tower setting.

With that disclaimer:
1 ) I'm OK with the setup down to this stage.

2 The assumption is probably wrong. There would not be a clear "Wile E Coyote" tank shaped hole cut cleanly through. The real result would be that the floor slab would break up - joists and pan break or bend and an area larger than the tank would get pushed down to the next level. Almost certainly it would tear the floor joists off the perimeter and core columns in preference to shearing the floor near the perimeter off the tank. (It is the same engineering logic as my other comments on "vampire stakes" - the connections to the columns are weaker in shear than the floor deck and joists.). So the falling tank now has a larger than tank "sheet anchor". It may break similarly through the next level BUT the "sheet anchor" would tend to plug the hole in that next floor - wedging the tank in place.

Then it becomes a race between "dragging more sheet anchors" and "sheet anchors being shear abraded and left behind in tatters". I'm engineer gut feeling judging (AKA "guessing" ) that "tatters" doesn't happen.

My money on arrest at 2nd, 3rd or 4th floor down.

3 Yes! in the real scene. No! if you continue with the "Wile E Coyote" version.

Depends how well the web of concrete, rebar, and trusses resist the initial crash.

Beach uses a total floor span max load of 29E6 tons. JSO had the numbers for per square foot or meter.

I don't picture the part of the floor span that fails , remains intact. It's going to deform into a somewhat parabolic shape. Concrete will shatter, its not high strength concrete..

The combo of bent trusses with a tank in the center with concrete rubble mostly lagging behind slightly, will hit next floor span at greater velocity than first impact.,,,, and so on.

But I readily admit I know more physics than applied structures physics.( colloquially referred to as engineering)

 

[jaydeehess]

Beachy beachy, are you being deliberately obtuse? Don't you know that "tons of TNT" or "Joules" a the D-baggy way of expressing energy?

Learn from notconvinced! You need to express this in keV!

It's 3,601,312,000,000,000,000,000,000,000 keV

Would it be D-baggy to use exponential notation.

 

[jaydeehess]

Ok, jj .... ....
Are you with me so far?

Pretty straight forward. I look forward to you continuing