An Overview and Debunking of the AE9/11T's List of Demolition Signs

Originally posted by ProudBird
Sorry, but that is irrelevant here. Can't believe anyone wrote that in seriousness.

Then you don't understand engineering design.

One of the first things you learn in engineering fundamentals is how engineering designs work.

The outer mesh of the WTC was multiple columns joined together like a lattice mesh. This type of design will distribute any load to other areas of the mesh. Anyone with an engineering background will understand this.

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As I'm sure you know by now building components are always designed to hold far more weight than the expected weight over it's lifetime (FoS). So not only was the facade a lattice type design, it would have been able to hold far more than it's own weight. That is why the plane left a hole and the building remained standing.
Even NIST doesn't attribute the damage to the facade to the collapses, it was sagging trusses, remember?

SO when are you OSers going to explain how sagging trusses can put a pulling force on the columns?

reply to post by ANOK


And sadly.....this delusional application and mind-set forms the foundation of your inability to understand the dynamics involved in the actual physics that took place on "9/11".

The delusional thinking is SO clear now....thanks.

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Originally posted by ProudBird
reply to post by ANOK

 

And sadly.....this delusional application and mind-set forms the foundation of your inability to understand the dynamics involved in the actual physics that took place on "9/11".

The delusional thinking is SO clear now....thanks.

And sadly you fail to address my points as usual. All you can do is attempt to insult and discredit.

Why did you even reply?

If I'm so delusional then explain how sagging trusses can put a pulling force on the columns like I asked?

Originally posted by ANOK
And sadly you fail to address my points as usual. All you can do is attempt to insult and discredit.

Why did you even reply?

If I'm so delusional then explain how sagging trusses can put a pulling force on the columns like I asked?

ANOK, I counted at least four instances where your question has been answered. On this thread and/or in others. Ignorance must be bliss.

reply to post by GenRadek


You may think it has been answered, but it hasn't.

I have rebutted all your claims so far. I am looking for an answer to that rebuttal. Just keep repeating the OS to me isn't an answer to my rebuttal.

I have explained why they couldn't pull in the columns, you have yet to actually address my points.

reply to post by ANOK


The intense fire caused the trusses to expand. But the perimeter wall was stronger and forced the trusses to bow.
As the fire cooled because the fuel on that floor had been used up, the trusses started to contract.
This contraction caued the exterior to be pulled inward.

Also in response to a earlier post of yours.
Yes the designers designed in a safety factor for severed exterior sections. But they didn't count on 35 side by side sections would ever be severed.

Originally posted by samkent
reply to post by ANOK

 

The intense fire caused the trusses to expand. But the perimeter wall was stronger and forced the trusses to bow.
As the fire cooled because the fuel on that floor had been used up, the trusses started to contract.
This contraction caued the exterior to be pulled inward.

Why would the contracting have any more force than the sagging?

Wouldn't the contracting just reverse the sagging? How could it pull on the columns unless the truss contracted to smaller than what it was before it sagged?

How is one hour long enough to heat them up and cool them down? One hour is not long enough to heat them up let alone cool them down. If they got hot enough to sag then they would have stayed hot for hours.

I don't think you've really thought about this much have you?

Also in response to a earlier post of yours.
Yes the designers designed in a safety factor for severed exterior sections. But they didn't count on 35 side by side sections would ever be severed.

Huh really, and how do you come to that conclusion? And where is your evidence that even happened?

Originally posted by ANOK
reply to post by GenRadek

 

You may think it has been answered, but it hasn't.

I have rebutted all your claims so far. I am looking for an answer to that rebuttal. Just keep repeating the OS to me isn't an answer to my rebuttal.

I have explained why they couldn't pull in the columns, you have yet to actually address my points.

And several have explained how they could pull in the columns that were sheared by the aircraft. It has to do with loading of trusses by the floors. Do we need to go through this again?

Originally posted by pteridine

And several have explained how they could pull in the columns that were sheared by the aircraft. It has to do with loading of trusses by the floors. Do we need to go through this again?

Again no they haven't.

How is loading of the floors got anything to do with it?

Are you saying the load on the floors increased to the point that the columns could no longer hold it?

How did that happen? How could the load change on the columns? If the trusses sagged then yes they may have a problem holding the load, but that has nothing to do with the columns holding the load of the whole floor assembly as it was designed to do, yes even during a fire.

Originally posted by ANOK

Originally posted by pteridine

And several have explained how they could pull in the columns that were sheared by the aircraft. It has to do with loading of trusses by the floors. Do we need to go through this again?

Again no they haven't.

How is loading of the floors got anything to do with it?

Are you saying the load on the floors increased to the point that the columns could no longer hold it?

How did that happen? How could the load change on the columns? If the trusses sagged then yes they may have a problem holding the load, but that has nothing to do with the columns holding the load of the whole floor assembly as it was designed to do, yes even during a fire.

Columns that are cut by the impacts no longer have support and are susceptible to distortion. They are limited in their outward movement by thermal expansion of the trusses. As the trusses heat, they lose strength and begin to sag under the weight of the floor and the contents loading the floor, including interior partition walls. Because they are attached at the core and the columns, they act as a cable with the weight of the floor pulling on the core and the columns. The sheared columns have less support than the core and preferentially move inward.

Originally posted by pteridine
Columns that are cut by the impacts no longer have support and are susceptible to distortion.

Again an assumption, you have no evidence that supports were cut.

They are limited in their outward movement by thermal expansion of the trusses. As the trusses heat, they lose strength and begin to sag under the weight of the floor and the contents loading the floor, including interior partition walls. Because they are attached at the core and the columns, they act as a cable with the weight of the floor pulling on the core and the columns. The sheared columns have less support than the core and preferentially move inward.

Again there is no more weight added to the trusses, why would you think that? So no more weight for the columns to hold.

The truss would not act like a cable, but again even if it did where is this extra load coming from? A cable is not sagging because it is hot, it is not pliable like softened steel, it's not even a close comparison other than the shape it makes.

Even IF there was more weight, do you know how much extra weight the columns could hold before failure? Do you know the FoS and the max pressure it could hold? If you don't then you have nothing to support your claim.

This is an important question, please answer at least this...

Do you think the 5/8th bolts were stronger than the core and outer wall columns?

If you don't then why didn't they fail first? If you do then how do you explain the floors collapsing at all, isn't weak connections part of your hypothesis? How did the floors pull in the columns if the connections were a weak point?

Buildings are designed to hold static vertical mass, not a mass in motion or a mass imbalanced. The core of WTC towers were insufficient to hold the structure of the bridge floor supports to the outer honeycomb support shell structure, when warpage occurs to the outer rigid design the compromise is spread to the least resistant components, the rest of the outer rigid support structure, that was warping and loosing its bridge like structure to the core that eventually set the upper floors in motion no building that size can support.

It was a risky innovative design to allow for the most unobstructed interior space, supported by that bridge floor design that required the inner core and outer shell working together, take out too much of those three components you have massive structural failure.

Originally posted by Illustronic
Buildings are designed to hold static vertical mass, not a mass in motion or a mass imbalanced. The core of WTC towers were insufficient to hold the structure of the bridge floor supports to the outer honeycomb support shell structure, when warpage occurs to the outer rigid design the compromise is spread to the least resistant components, the rest of the outer rigid support structure, that was warping and loosing its bridge like structure to the core that eventually set the upper floors in motion no building that size can support.

What warping? WTC 2 was on fire for less than one hour, not enough time to warp steel to such an extent that failure would occur.

It was a risky innovative design to allow for the most unobstructed interior space, supported by that bridge floor design that required the inner core and outer shell working together, take out too much of those three components you have massive structural failure.

No it wasn't, that's a myth. It wasn't the first tube in tube design, and most modern high rise buildings use this design.

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The core could easily stand without support from anything but itself. If it did fail it would not be straight down through the path of increasing most resistance. The 47 core columns tapered considerably from bottom to top...


wtcmodel.wikidot.com...

reply to post by ANOK


They were not a tube design like the Sears towers, he's only constructed one other skyscraper this way, about 1/3 the mass and height.

You did not see the outer walls bowing outward before the collapse?

Quit shoveling bullcrap!

reply to post by ANOK

What warping? WTC 2 was on fire for less than one hour, not enough time to warp steel to such an extent that failure would occur.

I posted a link yesterday that had an Excel spread sheet of steel beams and fire.
The time to failure was listed in seconds not hours. One example I tried gave 3370 seconds which is about an hour.

reply to post by samkent

The intense fire caused the trusses to expand. But the perimeter wall was stronger and forced the trusses to bow.
As the fire cooled because the fuel on that floor had been used up, the trusses started to contract.
This contraction caued the exterior to be pulled inward.

So you find the official version of collapse initiation implausible also?

Yes the designers designed in a safety factor for severed exterior sections. But they didn't count on 35 side by side sections would ever be severed.

How many did they count on being severed when designing for an aircraft impact?

reply to post by pteridine

Because they are attached at the core and the columns, they act as a cable with the weight of the floor pulling on the core and the columns.

This is an impossible mechanism. I'd love for someone to prove me wrong though, by showing the force in each truss member during this scenario.

The sheared columns have less support than the core and preferentially move inward.

The sheared columns can move where they like without affecting the behaviour of the load-bearing columns.

reply to post by Illustronic

You did not see the outer walls bowing outward before the collapse?

Quit shoveling bullcrap!

Inward bowing is claimed to be responsible for collapse...

Originally posted by ANOK
Again an assumption, you have no evidence that supports were cut.

Again there is no more weight added to the trusses, why would you think that? So no more weight for the columns to hold.

The truss would not act like a cable, but again even if it did where is this extra load coming from? A cable is not sagging because it is hot, it is not pliable like softened steel, it's not even a close comparison other than the shape it makes.

Even IF there was more weight, do you know how much extra weight the columns could hold before failure? Do you know the FoS and the max pressure it could hold? If you don't then you have nothing to support your claim.

This is an important question, please answer at least this...

Do you think the 5/8th bolts were stronger than the core and outer wall columns?

If you don't then why didn't they fail first? If you do then how do you explain the floors collapsing at all, isn't weak connections part of your hypothesis? How did the floors pull in the columns if the connections were a weak point?

The exterior columns were cut. The floor load was supported by the core and the exterior columns. When the exterior columns were cut and the floor trusses softened, the floor load did not have to increase to pull the outer columns inward.

reply to post by DrinkYourDrug

The sheared columns can move where they like without affecting the behaviour of the load-bearing columns.

The sheared columns were the load bearing columns!

There was no other form of support between the exterior columns and the central core.
It was 60 feet of light weight floor trusses that braced the exterior columns. These same trusses braced the internal core. I doubt the exterior columns could hold themselves upright for 110 stories without the bracing from the trusses.
That is the problem with the design they chose. And 911 is the reason that no other designer will ever use a similar design.

There were 59 columns on each side of WTC.
35 were severed by one plane.
That left 24 columns to support the weight of 15 stories on one side.
Now maybe if every other one had been severed.....

And you wonder why it collapsed???

Pick any wood framed house that uses only floor trusses.( without interior walls)
Load it fully with furniture.
Then cut out a three foot high section covering 60% of one side.
Do you think it will stand?