It is a "conclusion" that skyscrapers must have more steel toward the bottom in order to support their own weight.
Curiously we do not seem to have that data on any skyscrapers
World trade centre collapse, 9/11 conspiracy
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It is a "conclusion" that skyscrapers must have more steel toward the bottom in order to support their own weight.
Curiously we do not seem to have that data on any skyscrapers
What an odd thing to say. A friend of mine is an architect; she works on tall steel buildings (although nothing as big as the WTC.) She would find your claim that "we don't have structural data on any skyscrapers" pretty funny.
Can engineering schools make physical and virtual models of large scale man made physical objects?
The Collapse of the Tacoma Narrows Bridge
Tacoma Narrows Bridge Model
Tacoma Narrows Bridge Aeroelastic FSI Simulation
Tacoma Narrows Bridge Collapse simulation
3D Bridge Model Simulation
Using ANSYS Fluid-Structure Interaction to understand the Tacoma Narrows bridge collapse
https://www.youtube.com/watch?v=pcLg6C_WlHg
Published on Nov 7, 2018 Famous in Australia
Tacoma Narrows bridge collapse case study
https://www.youtube.com/watch?v=uXJ6CVBt8xk
CFD Simulation of Flutter (Tacoma Bridge)
https://www.youtube.com/watch?v=YzvFxF5LrRA
Tacoma Bridge Model Test 1
https://www.youtube.com/watch?v=QlW4bnxxMLY
Aerostatic Flutter at Tacoma Narrows Bridge
https://www.youtube.com/watch?v=xQwNMc19vFw
Tacoma Narrows Bridge Model, Long Walkthrough
https://www.youtube.com/watch?v=d6FKoPZURZo
Models have been done for the Tacoma Narrows bridge for nearly 80 years. The first was done before the bridge even collapsed in less than 4 months. So what is the "obvious reason" that it hasn't been done for the north tower? Just pretend there is no problem and there must not be one.
Find a link on the distributions of steel and concrete on anything over 500 feet tall.
Do architects do the engineering math on skyscrapers or do they just design how they look? Frank Lloyd Wright made buildings with leaky roofs.
https://www.businessinsider.com/wha...-2016-8#his-roofs-werent-properly-supported-1
A standard joke at the engineering school I attended was "architects take funny physics and funny math".
My pledge father was an architect. LOL Do you believe job titles tells you how much people know?
Well, the World Trade Center did have enough steel to support its own weight for years before 9/11. The conclusion we're talking about is your claim that aircraft impacts and fire could not have destroyed the buildings (message #312). I'm asking what calculations you have to support that conclusion.
Beaconator
Valued Senior Member
I made a bridge out a toothpicks once.
You can if you like. I don't feel like playing those games with you.
They do the math - and they calculate wind loads, creepage, yield strengths etc etc. And nowadays they simulate as well.
?? Right. And the local Souplantation leaks when it rains a lot. So?
Nope. Their knowledge does.
Nor does knowledge mean much without the training and experience to use it.
First off, I would like to express my deepest sorrow for all those lost and those who suffered during and after this awful tradgedy/event!
To my thread contribution. I always believed the USA government reports post 9/11. I am just that way...trusting in general. As time went on, I learned of conspiracy theories relating to this event. To be honest, I did not try to pick them apart. I simply acknowledged that alternative viewpoints existed in the world.
More time passed and I started to read more. Trying to remain objective. I never was able to understand, pro or con, aircraft fuel burning temperatures and ductile strength loss of steel under such temperatures. It was beyond my abilities.
One day I read, or watched a tv program, regarding the Tower designs. It helped me greatly understand the, "pancake" collapse principle of the towers falling. Basically, the architect engineered the structure to be mainly vertically supported by the building exterior...or the shell. It allowed more open visual space within via reduction of support columns.
It was basically that time that I had personal closure and explanation of how they (the towers) fell. The breach of that high load bearing exterior was unforgiving. Instead of the buildings having an internal spine, or supporting internal membrane, the weight distribution was directed at the exterior shell or walls.
It makes sense (to me anyway). Once, so to speak, you crack an egg shell.. the rest falls apart rather easily
Again, tragic loss of life in any event. Sad day for families...the USA...and the world as it unfolded!
To my thread contribution. I always believed the USA government reports post 9/11. I am just that way...trusting in general. As time went on, I learned of conspiracy theories relating to this event. To be honest, I did not try to pick them apart. I simply acknowledged that alternative viewpoints existed in the world.
More time passed and I started to read more. Trying to remain objective. I never was able to understand, pro or con, aircraft fuel burning temperatures and ductile strength loss of steel under such temperatures. It was beyond my abilities.
One day I read, or watched a tv program, regarding the Tower designs. It helped me greatly understand the, "pancake" collapse principle of the towers falling. Basically, the architect engineered the structure to be mainly vertically supported by the building exterior...or the shell. It allowed more open visual space within via reduction of support columns.
It was basically that time that I had personal closure and explanation of how they (the towers) fell. The breach of that high load bearing exterior was unforgiving. Instead of the buildings having an internal spine, or supporting internal membrane, the weight distribution was directed at the exterior shell or walls.
It makes sense (to me anyway). Once, so to speak, you crack an egg shell.. the rest falls apart rather easily
Again, tragic loss of life in any event. Sad day for families...the USA...and the world as it unfolded!
It is just so funny that the NIST rejected the pancake theory. I have Googled and linked to it so many times I am not going to do it again.
RainbowSingularity
Valued Senior Member
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https://en.wikipedia.org/wiki/The_NIST_World_Trade_Center_Disaster_Investigation
Findings
The Twin Towers
The investigation team integrated their metallurgyanalysis, experimental results and computer simulation with video and photographs of the destruction and eyewitness accounts to form their understanding for how the buildings collapsed. They came to two conclusions:[15]
- A conventional fire should not have caused the collapse of the 110-story skyscrapers in the absence of structural and fire-proofing insulation damage.
- The towers would likely not have collapsed if not for the impact and damage that the aircraft caused to the fire-proofing insulation.
- First, the floors that lost fire-proofing insulation due to debris impact began to sag as a result of the high temperature of the fire.
- The sagging floors pulled inward on the girders and caused the exterior walls to deform.
- The exterior walls began to buckle under the combined forces of the sagging floors, the fire, and the severed core columns from aircraft impact damage.
- Finally, the exterior walls caved in and the buildings collapsed. The stories below provided little resistance to relatively tremendous energy of the falling building, allowing them to fall very quickly.
Nist aside. With 110 parallel floors falling amost all within their footprint (not timberrrrr, like a tree falling), the pancake collapse did take place for at least most of tge structure. Now what cause the initial collapse? I tend to embrace the idea that weakened slab supports from heat and the extra weight of a jetliner and fuel (before the fuel drained or burned off) triggered the 1st pancake reaction.
RainbowSingularity
Valued Senior Member
did it collapse or was it knocked down ?
DaveC426913
Valued Senior Member
It collapsed - after suffering fatigue from impact of a jet at cruising speed, carrying jet fuel. Something it was never designed - even in an engineer's worst nightmare - to withstand.
RainbowSingularity
Valued Senior Member
did they decide the small sectioning(& bolting system) of the main steel internal frame was an engineering flaw(inappropriate and degenerative to modern technological engineering knowledge) ?
i got the distinct impression the entire building was "experimental"
which probably means the entire complex of buildings was "experimental"
DaveC426913
Valued Senior Member
All buildings that stretch the boundaries of engineering must have a first time.
It's incremental. I don't think that crosses the threshold to 'experimental'.
So it should be possible to make a computer simulation of the North Tower. Remove 5 levels, 91 thru 95, and drop the top 15 levels onto the bottom 90. Wouldn't accurate data on steel and concrete distributions be required?
It is interesting that "conspiracy theorists" have some kind of psychology but people who believe what authority tells them do not. This is physics not psychology.
Go for it!
Where is the data on the distributions of steel and concrete down the structure? Why isn't it in the 10,000 page NCSTAR1 report? The funny thing is that the report does say that information is necessary to analyze the motion of the buildings due to the aircraft impacts.
A good physical model should be at least 13' 8" and 800 lb. Big and heavy enough to be dangerous. But a small model demonstrating the physics is not difficult.
You posted several links to that data previously. Look it up!
Won't work. The square/cubed law makes any such model effectively useless.
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