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A Question for Heiwa - WTC Safety Factors

Heiwa said:
You should read my papers at http://heiwaco.tripod.com/nist3.htm and http://heiwaco.tripod.com/nist7.htm . Explains everything quite clear!
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I see from (part III stage 2)

Stage 2: At such temperatures, structural steel suffers a decrease of yield strength and loses its load carrying capacity! (Actually the load carrying capacity is reduced abt 20% at 500°C and with a Factor of Safety >3 no serious decrease of load carrying capacity should happen). Actually the load carrying capacity is reduced abt 20% at 500°C and with a Factor of Safety >3 no serious decrease of load carrying capacity should happen).
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You have claimed FOS>3, but only from this

The upper part of WTC 1 is a problem for NIST. Its weight was not massive, only about 33 000 tons and the uniform density was <0.18! It consisted of 95% air. The load bearing columns - the primary structure carrying this weight - occupied only 0.13% of the total foot print or floor area in the initiation zone - the rest was air, floors and furniture, which is an indication how strong the lower structure columns were! The compressive static forces and associated stresses in the columns were low - <30% of the yield stress, i.e. a Factor of Safety, FoS, against yield more than 3. And the built in strain energy, strength, to keep the upper part together was exactly the same as for the structure below.
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There is no calculation to show how you come to this figure. You then go on to assume decreased load carrying capability based on this figure at 500°C when we know that structural steel lose atleast half of their yield stress at this temperatures.

Please show you calculations for a FoS > 3.

You would be much better off writing a proper paper than wasting time with your webshite.

Edit: I'll also add that a narrative is "a story or account of events". If the collapse is as you claim then a narrative of what happened is needed. i.e. how much explosive was used, which parts of the structure needed wiring up, what explosive was used, how was it detonated, how long did it take for this to be accomplished, by whom, how and when etc, etc. It's another whole topic.
 
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After looking briefly at Heiwa's web page I'm of the opinion that he is capable of being in error on many subjects
 
GregoryUrich said:
Since Heiwa seems unlikely to provide any calculations to back up his assertion regarding FoS > 3. Perhaps he would at least demonstrate what is wrong with this calculation demonstrating the that the FoS in the core was closer to 2.

http://www.cool-places.0catch.com/911/loadDistribution_v1.pdf
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My calculations are at http://heiwaco.tripod.com/nist0.htm#3 ! Quote:

The mass above the core is also 16 500 tons supported by the 47 core columns with total area 2.1 m². On average each core column carries abt 351 tons so the average compression is 786 kgs/cm² or 78 MPa or 31.7% of yield.

Somewhere else in my paper I show that the critical buckling stress of a core column exceeds yield, assumed properties of the steel, &c.

However, the main observation/conclusion in my paper is that a small upper part of a structure of many elements cannot crush the lower part of the structure due to gravity alone and some local failures and nobody seems to be able to debunk that! FoS of elements do not really matter.
 
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George152 said:
After looking briefly at Heiwa's web page I'm of the opinion that he is capable of being in error on many subjects
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Please, copy/paste any factual observation on my web page that you think is in error and I will clarify!
 
Sunstealer said:
Please show you calculations for a FoS > 3.

You would be much better off writing a proper paper than wasting time with your webshite.
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Re FoS > 3 see answer to Urich above.

I think I write proper articles on my web site. I get many mails of appreciation.
 
Sunstealer said:
Edit: I'll also add that a narrative is "a story or account of events". If the collapse is as you claim then a narrative of what happened is needed. i.e. how much explosive was used, which parts of the structure needed wiring up, what explosive was used, how was it detonated, how long did it take for this to be accomplished, by whom, how and when etc, etc. It's another whole topic.
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I agree. Interesting stuff! How did the gangsters do it? I have some comments about it at the end of my WTC 7 paper, i.e. use of energetic materials, which are not really explosives. There are only 24 core columns in WTC 7 that must be suddenly cut at two locations, say at floors 6 and 13 and then the whole upper part above drops down ... free fall. As the floors may be service floors of some kind, installation of the remote controlled, pre-fab cutting devices is easy and quick.
Similar devices were probably used in WTC 1 and 2. Bigger job, though, but feasible. But it is outside my scope of expertize. I have of course informed FBI twice but have not heard from them.
 
beachnut said:
It explains you are not very good at physics, structures, fire science, and logic. Your web pages are pure junk. 7 years and you can’t get published with your delusions.


You failed to provide any real answer so far, save posting your failed web site as if it was more than a collection of failed delusions.
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Heiwa, I don't see this as an insult but also as an attack to your profesion.
What are you waiting for to take this person to a court of law and prove him wrong with your work?
 
About the same time he works out that his "FoS" calculation isn't worth the paper it's written on. That's not how you even come close to calculating it for complex structures. You'll note that he's not addressed the Demend to Capacity data at all......
 
HENTAI DOUKYUSEI JP said:
Heiwa, I don't see this as an insult but also as an attack to your profesion.
What are you waiting for to take this person to a court of law and prove him wrong with your work?
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JREF is just a cyber place to discuss in a friendly and lively way. I get plenty of good ideas from the discussions. Of course, there is plenty of crap in most threads. Use the ignore option and it appears friendlier ... and less lively? Kodomo demo shitte imasu.
 
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Heiwa said:
JREF is just a cyber place to discuss in a friendly and lively way. I get plenty of good ideas from the discussions. Of course, there is plenty of crap in most threads. Use the ignore option and it appears friendlier ... and less lively? Kodomo demo shitte imasu.
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Jings, the irony.
 
Capacity is calculated from the characteristics of a structural system or components and elements, together with a mathematical definition of the behaviour of the structural materials used (yield stress, buckling stress, tensile strength, etc.). Once capacity has been calculated, designers check to make sure the capacity is greater than demand.

Demand is usually understood by structural engineers to mean forces and displacements in a structural system or component or elements produced by applicable actions such as loads.

Evidently a structure A has capacity to to withstand the demand put on it by a part C of itself, even if that part C drops on and contacts the remainder of the structure A.

Reason is that the capacity of part C is less than demand put on it at contact with A.
 
Heiwa said:
My calculations are at http://heiwaco.tripod.com/nist0.htm#3 ! Quote:

The mass above the core is also 16 500 tons supported by the 47 core columns with total area 2.1 m². On average each core column carries abt 351 tons so the average compression is 786 kgs/cm² or 78 MPa or 31.7% of yield.

Somewhere else in my paper I show that the critical buckling stress of a core column exceeds yield, assumed properties of the steel, &c.

However, the main observation/conclusion in my paper is that a small upper part of a structure of many elements cannot crush the lower part of the structure due to gravity alone and some local failures and nobody seems to be able to debunk that! FoS of elements do not really matter.
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OK. There are your mistakes. (I assume you are using floor 97 with 33,000 tonnes total mass above as usual.)

In accord with the correct load distribution calculated by Urich [2007] (which concurs with S. W. Banovic, T. Foecke, W.E. Luecke, et al. “The role of metallurgy in the NIST investigation of the World Trade Center towers collapse”, JOM, vol. 59, no. 11, pp. 22-29, November 2007.)

the values you should be using are:

The mass acting on the core is closer to 19,500 tonnes.

The total core demand is 1,9081E+08 N.

Correct calculation of buckling stress here using the actual properties of the steel as opposed to your assumptions.

The load capacity of the core is 4,3603E+08 N.

Core DCR = 44% (FoS = 2.29) prior to aircraft impact damage.

Core DCR = 51% (FoS = 1.96) after aircraft impact damage.​
 
Evidently a structure A has capacity to to withstand the demand put on it by a part C of itself, even if that part C drops on and contacts the remainder of the structure A.

Reason is that the capacity of part C is less than demand put on it at contact with A.
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No, it's not "evident" because there there are issues around dynamic loadings and, arguably far more importantly, changing load paths as a result of the collapse itself.

However this is a thread about Factors of Safety; you have failed to produce competent calculations or explain why the Demand to Capacity calculations differ so widely from your own - and only your own - expectations that "FoS>3".
 
Gregory

It appears that you calculations are based only on the vertical loadings on the core.
Is that a fair summary?


Heiwa

Gregory is providing the kind of response that you, if you understood the issues, should be putting together. Although the figures could be wrong - I'm no engineer (and neither are you).
 
Architect said:
Gregory

It appears that you calculations are based only on the vertical loadings on the core.
Is that a fair summary?

Yes, the calculated DCR's (and FoS) for the core are based on static vertical loading of the core.
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