WTC collapses - Layman's terms again

[X]

affected.




[qimg]http://img237.imageshack.us/img237/6131/stress1ai7.gif[/qimg]

does it show that ONLY the most upper floor is affected?

Without knowing the loading (I'll assume uniform), the scaling factor for stess, material, model make-up, etc, this is pretty but mostly useless.

However, I do note that while the upper columns flex, the ones below do not.
It appears the flexing is due to the flexing of the upper floor.
This demonstrates a rigid connection, as if everything were one uniform unit.

I'm not familiar with this program, so I don't know if it can do the following, but here's my suggestion:
Try it again with appropriate materials and material strengths (you'll probably have to model the floor trusses), and specify material properties appropriate to the steel in both the cool and heated areas.
As well, make your connections out of appropriate materials, flexibility, and ultimate tensile strength.

I'm sure other people can add in details I may have missed in my quick suggestion.

 

[Heiwa]

What I don't understand is that an engineer and a ship constructor don't understand the basic facts about physics that I learned in high school?!

As I understand it Heiwa seems to think that vertical accelerating forces involved between the upper and lower part of the towers are comparable to his knowledge about the horizontal deccelerating forces between colliding ships!?

How can't he know about the simple rules of pressure (the smaller the area of the force the higher the pressure).

How can he claim that the floors which where built to withstand horizontal forces should be able to hold the vertical forces of the upper part of the building?

How can he dismiss the huge potential and kinetic energies involved in the collapse?

How can he claim all this and still consider himself an expert of the subject?

Btw I am only asking questions. ;-)

Ps: I only had basic physics courses in high school.

Very good. Simple polite questions! A force F (unit Newton - the guy on whose head an apple dropped) is always a force! Applied to a mass (unit kilograms) it accelerates (unit m/s²) the mass, e.g. applied to a ship it accelerates the ship (you know a propeller produces this force), applied to an upper block of a building that comes loose and can drop, it accelerates the upper block (you know gravity produces this force). Same principles. You need energy E (unit Joule or Newton meter (same thing)) to maintain the force F every meter displaced.

So why does not a ship accelerate to the speed of light when a force is applied to it? Aha! Resistance of some type. The ship acceleration is slowed down by resistance! Until equilibrium is maintained. Driving propeller force = opposite reaction resistance force = no acceleration (and some constant speed). Same with a dropping upper block. Does it meet resistance, it is slowed down. Does it meet plenty of resistance, it stops. It is arrested.

You can read more about at it http://heiwaco.tripod.com/STJarticle.doc

Nothing magic about that. Friendly comments are always welcome. My audiences are mainly children and people interested in safety of ships, but for some reason I got interested in 911 WTC collapses. Same things actually from a physical point of view. Hope you understand now?

But remember that when A argues that B = f(x,y,z,u,v,w) = NIST forgot something (e.g. the possibility of collapse arrest or where the upper block went), don't call person A a lier or that argument B is stupid because that is not the topic. Topic is x,y,z,u,v,w .

 

[DC]

Why is it the people that argue the strongest about how a building should perform know the least about the subject?

DC If you have kids grab their Lego's and build a single block width tower 20 feet tall. Hey one stands on top of the other. Why wouldn't 300 of them do the same thing? (Hint= Buckling) Core "blocks" do the same thing.

can you tell me why i should build a tower out of plastic blocks with lose connections, where i dont get any buckling of the blocks alsong i dont use bolts or glue. they will wall appart, that is totaly over simplified.

and i didnt want to prove anything else thant that the lowers floors are also affected.

while i must say lego prolly influenced my education direction it most, it was Lego Technics (nowadays i would prolly go into electronics^^, they have video "recognition"

i never claimed to know more thant an engineer , especially not a structural engineer, nor did i ever claim to have knowledge into structural engineering.
and most prolly the next few post a few will post and "you demonstrated it...."
(no i dont belive in seeing the future)

 

[Heiwa]

Without knowing the loading (I'll assume uniform), the scaling factor for stess, material, model make-up, etc, this is pretty but mostly useless.

However, I do note that while the upper columns flex, the ones below do not.
It appears the flexing is due to the flexing of the upper floor.
This demonstrates a rigid connection, as if everything were one uniform unit.

I'm not familiar with this program, so I don't know if it can do the following, but here's my suggestion:
Try it again with appropriate materials and material strengths (you'll probably have to model the floor trusses), and specify material properties appropriate to the steel in both the cool and heated areas.
As well, make your connections out of appropriate materials, flexibility, and ultimate tensile strength.

I'm sure other people can add in details I may have missed in my quick suggestion.

If you read my article (message 1 of this thread) you would know the principle. It is like children jumping in a bed. The details are in the article. All explained - in layman's terms.

 

[Dumb All Over]

If you read my article (message 1 of this thread) you would know the principle. It is like children jumping in a bed. The details are in the article. All explained - in layman's terms.

Why would anyone read your article? It is like childen jumping on my head. You dishonestly portrayed your article as something that was peer-reviewed when clearly it is not. You lied. Why should anyone take you seriously after discovering your big fat lie?

 

[DGM]

Heiwa in a paragraph;

There have been 10,000's of airplane crashes in the world since aviation took off around 1910 and at every crash there was plenty of wreckage. 911 is the first and only time when four airplanes have crashed on the same day without leaving any wreckage ... at all! What a coincidence! ..."

http://patriotsquestion911.com/engineers.html

Conspiracy/propaganda first, engineer only if it suits his agenda. His lies will never stop.

 

[Dumb All Over]

what exactly are his lies?

Have you not been following this thread? Do you really not know what his lie is? Then, of course, I guess I'm not surprised as you can't help lying yourself.

What is it with these liars? Am I missing the joke or something?

 

[DC]

My "Legotower"

Stress

Displacement

my model is only one solide steel (AISI304) model. 4200 mm x 5200 mm
12 "core columns" 200 mm x 200 mm, 1500mm long
36 "perimeter columns" 200 mm x 200 mm, 1500mm long
1 "Basement" and 5 "floors" 200mm thick
1 load of 22.481 lb (100 N) on most upper floor.
0.000004188 mm max displacement. (4.188e-006mm)

i did not want to illustrate any collapse arrest.
i just wanted to show that "spring" effect which i consider a fact.
i did not want to show buckling, breaking joints, a collapse, a CD, a EWP or anything else than C

the C from Dr. Bazant.
also seen in the paper you linked me to.

For a short time after the vertical impact of the upper part, but
after the elastic wave generated by the vertical impact has propagated
to the ground, the lower part of the structure can be approximately
considered to act as an elastic spring @Fig. 2~a!#.
What is its stiffness C? It can vary greatly with the distribution of
the impact forces among the framed tube columns, between these
columns and those in the core, and between the columns and the
trusses supporting concrete floor slabs.

i did not add any forces on other floors, because i think that is influencing the picture far more, because then , the lower columns would be under load.
i just wanted to show the aditianal load affecting also the other storey, which is a fact.

i am stunned how heavy i have to backup an illustration of a fact.

i hope you all demand the same from your government, agencys, and commissions.

PS: Newton Bits or Dr. greenings, in hope you havent me on ignore jet and reading it, could you pls correct me if i am wrong by saying this is illustrating this "spring effect"?

 

[DC]

and now can someone pls explain me in layman terms, why the lower part is considered a sping, but not the upper part?

 

[Dumb All Over]

and now can someone pls explain me in layman terms,...

No, I'm sorry. I cannot explain you in layman's terms or any other terms. It would be too much like children jumping on my head.

 

[stateofgrace]

So why does not a ship accelerate to the speed of light when a force is applied to it? Aha! Resistance of some type. The ship acceleration is slowed down by resistance! Until equilibrium is maintained. Driving propeller force = opposite reaction resistance force = no acceleration (and some constant speed). Same with a dropping upper block. Does it meet resistance, it is slowed down. Does it meet plenty of resistance, it stops. It is arrested.

Really?

So why doesn't a car accelerate to light speed? Air resistance?

 

[DC]

No, I'm sorry. I cannot explain you in layman's terms or any other terms. It would be too much like children jumping on my head.

Do you understand the "collapses" or do you trust on those that claim to understand them and claim to prove the towers had no chance to survive?

 

[DGM]

So why doesn't a car accelerate to light speed? Air resistance?

Of course he fails to mention that when a ship hits something they turn off the propeller. Gravity not so much, it keeps on going. I love his answer for how he knows it will stop. the old reliable "gut feeling" every real engineer relies on.

 

[DC]

erm ok, Heiwa, in case you are indeed Anders Björkman. Do you doubt the impact of airplanes `?

 

[stateofgrace]

erm ok, Heiwa, in case you are indeed Anders Björkman. Do you doubt the impact of airplanes `?

Yes he does. He has also claimed on this forum that the reason people jumped to their deaths from WTC 1 was not because of the intense heat but because they got scared when they saw WTC 2 collapse. He as also claimed that the reason the massive weights above each impact zone did not hit the lower sections of the towers was because they were demolished in mid air. He as also claimed that the largest forensic investigation in US history into the pentagon was a massive cover up.

Don't believe me? Ask him.

 

[X]

and now can someone pls explain me in layman terms, why the lower part is considered a sping, but not the upper part?

Probably because one end is fixed, while the other recieves a force input.
The upper part is not fixed, and thus is not forced to absorb the impact.
(It would, I think, also act as a spring. This is due to its large mass. However, it's "springing" would be substantially less than that of the lower block. Architect, R.Mackey or rwguinn can correct me if I'm wrong here.)

 

[DC]

Probably because one end is fixed, while the other recieves a force input.
The upper part is not fixed, and thus is not forced to absorb the impact.
(It would, I think, also act as a spring. This is due to its large mass. However, it's "springing" would be substantially less than that of the lower block. Architect, R.Mackey or rwguinn can correct me if I'm wrong here.)

when you fix a spring on the ground, and you drop something on it, the spring will deform and resist that impacting force.

when you drop a spring on the ground, does it deform at impact?.

or did you ever se a highspeed camera video from a ball when it falls on the ground?

 

[peteweaver]

Edited by Darat: 

Breach of Membership Agreement removed.

How could WTC1, 2 collapse due to gravity forces alone after some local failures up top?

Heiwa

Because due to structural failiure, the upper section became a dynamic load, and fell onto the floors below with such force that they couldn't withstand the blow, and they too failed falling onto the floors below them, which failed and fell.

Its not rocket science.

 

[peteweaver]

when you drop a spring on the ground, does it deform at impact?.

When you drop a concrete breezeblock on your foot, does your foot resist the impacting force ? Or would you agree that your foot is not designed to withstand the force of breezeblocks falling on it ?

The upper section of the twin towers falling onto the floors beneath, was a tad heavier than dropping a small steel spring onto the ground.

 

[Newtons Bit]

and now can someone pls explain me in layman terms, why the lower part is considered a sping, but not the upper part?

It's because the lower part is still in the elastic stress region and the upper part goes into the plastic region. Simply put, the floors below the topmost stay "springy" and the one at the top buckles and breaks.

The energy required to compress the lower part of the tower does not simply vanish. If you take a normal spring, put a load on it then release it, it bounces back and forth. The lower tower does this.