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Merged Why WTC7 should not have collapsed

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Homeland Insurgency said:
So then post some and their personal opinions. It shouldn't be hard with 99.999% of them.
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The other 10 engineers in my office all concur with the NIST report. Most of them think that designing buildings for burn-out, as recommended by NIST, is absurd.
 
Grizzly Bear said:
Regardless of what goal posts you shift the analogy is invalid. In building structures there's a concept called the square-cube effect.

Say for example we have an umbrella shaped shelter that is 10 ft & 10 ft deep with a flat concrete roof 1 ft thick and a single center column having an area of 1ft2.

Concrete is roughly 150 Lbs/ft3, the total load on the column is about 15 kips, and the compressive stress is 15 kips/ft2
Note: 1 kip = 1,000 lbs

Take the same structure and increase the size 3 fold, overall size increases to 30 ft in each dimension; The roof slab would increase in thickness to by 3 fold as well resulting in a slab with about 2700 ft3, and a weight of 405 kips. The area of the center column would increase to 9 ft2. The column stress would be 45 kips, which is three times that of the original smaller structure. In order to effect the same compressive stress , the column area would have to triple to 27 ft2 with column dimension increasing to 5.2 ft on each side.


In other words even using the same materials in you "analogy" would result in drastically different results. The problem is compounded just by using different materials... A 1 ft3 volume of concrete can be loaded with many times it's own weight, however a slab of concrete the size of a building may only support double it's own weight.
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Which is exactly why I've been trying to get Heiwa to provide calculations for his scale experiments.

I thank you for putting more clearly than I managed to.
 
They agree with NIST's account of events, but not with their recommendations.
 
Homeland Insurgency said:
They concur with NIST but they think it's absurd?
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I'd hazard that Newton's Bit means that his colleagues agree with NISTs findings on the collapse, but think the recommendations in building design change are absurd.
 
[X] said:
Which is exactly why I've been trying to get Heiwa to provide calculations for his scale experiments.

I thank you for putting more clearly than I managed to.
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I remembered that this stuff is discussed in one of my older text books, If I get the chance maybe I'll post the pages that cover it. What's just as important to understand is that the strength of a column is dependent on its cross sectional area of structural members the weight is determined by volume more or less, and then you add the live and dead loads after wards.

In general as the structure is scaled up the volume (and gravity load) increases at the rate of the cube of the scale, while its members strengths increases at a slower rate of the square of the scale. Neither Heiwa, HI, or for that matter any other irrational CT member understands that and yet they persist in using weak analogies in some vain effort that they'll somehow equate to each other.

Richard Gage takes it to the extra leap by trying to equate card board boxes to the towers, and he wonders why he's being ridiculed....




This same effect is present in the ratio of weight that a beatle can carry compared to that of a human, as well as to the varying skeletal features on any animal really...
 
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You might want to show this thread to NIST. I don't think they're aware of your findings.
 
It looks like we're back to the old Indestructible Skyscraper Canard.

If column 79 didn't fail after losing lateral support why did the penthouses bend downward right where column 79 interfaced with the roof?
 
This thread needs more Newtons Bit and Architect. Though I have a hard time following along, I do like it when they break out the mathematics to validate their positions. Something conspiracists seem particularly incapable of doing.
 
leftysergeant said:
The table analogy is absurd. You are not talking about the same materials or forces.

Your arresting mechanism assumes only one action, thje collapse of the floors. You disregard the other floor slabs pushing against the vertical columns after the slabs on the other side have fallen. You have a lot of forces pushing unevenly in several directions. That was what Sunder repeated several times in the report, when he emphasized the asymetricality of the floors.
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No forces are pushing! After column 79 fails the floor (and roof) beams attached to it are assumed to be disconnected (column 79 drops down and is out of the action).
At this instance the beams are still hanging on their other end connections to other columns and hinges down. No pushing in several directions. Just pulling down. And that's it.
Only thing that can happen is that some beams shear off the remaining end connection and drops down. The secondary beams cannot damage other primary structure columns.
REPEAT. A beams is first connected at both ends to columns. Then one end connection is locally damaged, when that column (no. 79) fails and, yes - an asymetrical state develops - and the beam is only connected at its other end. So the beam hinges down around that connection and the load on the beam slips off. End of failures unless the other end connection fails, and the beam drops down.
That adjacent column will not fail at it is still supported by many other beams in all directions. It is called redundancy.

The table analogy is not absurd. Remove one leg ... and there is no global collapse. You can stack a number of tables on top of one another and remove any leg anywhere. No collapse.

Sunder & Co suggest otherwise but cannot show any calculations for their absurd allegations. Sunder & Co actually suggest that all steel towers in the USA are wrongly designed and built and removing one primary part collapse follows as shown in some Hollywood pictures. Primary and secondary structural parts flying in all directions. It is insane. It is NWO.
 
Travis said:
It looks like we're back to the old Indestructible Skyscraper Canard.

If column 79 didn't fail after losing lateral support why did the penthouses bend downward right where column 79 interfaced with the roof?
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Column 79 is assumed to fail first due to a local fire. Read the report. But the penthouse was also supported by other columns and they could not fail due to failure of columnn 79 (unless assisted of course).
 
Galileo said:
non-responsive. This is a forum for the scientific.
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It's not non-responsive at all. Heiwa starts with no assumptions about the weight, composition or strength of the structure, none about the temperature, extent or duration of the fires, none about the thermal properties of the materials involved, and makes no calculations; he simply advances a line of reasoning which he claims leads to the conclusion that progressive collapse cannot occur. In the absence of any data or calculations, this can only be assumed to be a perfectly general result. Since progressive collapse does occur, it is also a completely wrong result. Having thus summarised Heiwa's arguments, I can conclude that they are not worthy of further consideration. This is called attacking the argument.

In effect, Heiwa is saying, not that WTC7 should not have collapsed, but that nothing can ever collapse. It's a perfectly reasonable response to say that this conclusion is insane.

Dave
 
I don't understand why anyone is taking this latest NIST joke report seriously. How can such a study claim to be authoritative when it's not even based on physical evidence but on infinitely malleable computer models and guesswork?

I'm quite sure that NIST "scientists" would be able to demonstrate, mathematically, that the moon is made of cheese and bricks are made of wood and their cultish ideological soulmates would be on here enthusiastically "proving" them right.
 
Heiwa said:
Column 79 is assumed to fail first due to a local fire. Read the report.
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This is like saying George Washington became the first President of the United States because of his leadership in the French and Indian War. There are a few steps in between.

Read the report yourself.
 
JihadJane said:
I don't understand why anyone is taking this latest NIST joke report seriously. How can such a study claim to be authoritative when it's not even based on physical evidence but on infinitely malleable computer models and guesswork?
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You need to re-assess your definition of the term "physical evidence". It includes, but is not limited to, "steel samples from collapsed buildings".

You also need to re-assess your definition of "infinitely malleable" to exclude requirements to comply with physical laws and observed phenomena.

Finally, you might consider that, in the light of your repeated claims of minimal understanding of engineering issues, your admittedly uninformed opinions on these issues might not be seen as compelling evidence.

Dave
 
Dave Rogers said:
You need to re-assess your definition of the term "physical evidence". It includes, but is not limited to, "steel samples from collapsed buildings".
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What else does "physical evidence" include?

You also need to re-assess your definition of "infinitely malleable" to exclude requirements to comply with physical laws and observed phenomena.
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Good point. Infinite was a bit of an exaggeration!

Finally, you might consider that, in the light of your repeated claims of minimal understanding of engineering issues, your admittedly uninformed opinions on these issues might not be seen as compelling evidence.

Dave
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It requires absolutely no knowledge of engineering issues to know the removing and destroying all the physical evidence from a crime scene fatally compromises any investigation.

This is why criminals do their best to destroy all physical evidence of their crimes. It makes it far more likely that they will get away with their crimes.
 
Heiwa said:
Only thing that can happen is that some beams shear off the remaining end connection and drops down. The secondary beams cannot damage other primary structure columns.
REPEAT. A beams is first connected at both ends to columns. Then one end connection is locally damaged, when that column (no. 79) fails and, yes - an asymetrical state develops - and the beam is only connected at its other end. So the beam hinges down around that connection and the load on the beam slips off. End of failures unless the other end connection fails, and the beam drops down.
That adjacent column will not fail at it is still supported by many other beams in all directions. It is called redundancy.
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I'll repeat my question yet again:
Again on what grounds? Does this take into account secondary effects from structural damage on one side? Does this take into consideration plastic creep of some portions of the structure and/or connections? Does it consider shear forces applied by thermal expansion and contraction cause by structural members being heated by the fires? Does this consider WTC 7's own design for the structural frame?

You apply a generic standard as if the structure will behave the same regardless of construction methods? If you expect to have the slightest chance of convincing me you will need to explain why the same behavior will be expected in different designs. What considerations have you made? And do any include the above I mentioned?



Heiwa said:
The table analogy is not absurd. Remove one leg ... and there is no global collapse. You can stack a number of tables on top of one another and remove any leg anywhere. No collapse.
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No Heiwa, it is ridiculous to assume a table comes anywhere near comparison to a building. I explained why already, get off the subject and reread my post regarding it: LINK

Stop using that silly weak analogy, it really isn't working Heiwa
 
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