Challenge: Demonstrate Sagging floor Trusses Pulling in Perimeter Columns

enik said:
Any reason you don't go over to that site and ask those questions?
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A forum based on fiction? It is the perfect place for the fiction of an inside job.
Your stuff, the inside job is for fiction, you flourish at sites based on fantasy.
All you can do is keep asking questions, you can't prove your fantasy; stuck in perpetual questions, and more questions, and more questions...

enik said:
And yet this entire challenge is trying to support the NIST hypothesis. Why don't you give it a try.
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Don't need nist, we saw on 911 the collapse due to impacts and fire. No CD. Makes your inside job a fantasy made for LC forum. Fiction.

JSanderO said:
Let's begin...

Where was the inward bowing?
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Are you going to help enik make his inside job more real? How? You don't do models. They are cartoons?

Not cartoons, reality...
http://s286.beta.photobucket.com/us...g.html?&_suid=1363371593746039645042516421913
Some of that Major Tom observable. lol, we all have Major Tom's work, it is public domain, not his work, but photos, and video...

Too bad you can't help enik and his inside job. You said it was an inside job too, but changed your mind?
 
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Newtons Bit said:
Have you generated a report yet, enik? It's been 3 days. I've provided a ton of stuff for you but you've provided very little for me.
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Yes I did. I even offered to email it to you. I am even willing to take it offline and discuss the differences between our two analyses.

You did provide me with a read out of your analysis, but you don’t want to answer a few questions nor do a simple hand calculation on your first case. It would be nice to know more about the RISA software and why you are getting higher values than me, but I don’t want to get into an argument on who has the better FEA software in this thread.
 
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enik said:
Yes I did. I even offered to email it to you. I am even willing to take it offline and discuss the differences between our two analyses.

You did provide me with a read out of your analysis, but you don’t want to answer a few questions nor do a simple hand calculation on your first case. It would be nice to know more about the RISA software and why you are getting higher values than me, but I don’t want to get into an argument on who has the better FEA software in this thread.
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How does this challenge work with your inside job theory?

http://s1.zetaboards.com/LooseChangeForums/topic/4724858/1/
Inside Job Evidence is in the Physics of WTC #1
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Where is your work related to the Inside Job Evidence? Where is the Evidence? Even Jones publishes his failed papers at fake journals, open access quick peer review guaranteed by paying... etc. Where?

You can't prove your inside job, so you ask questions? What kind of tactic is that?

You did better at the Loose Change 911 forum for idiotic claims on 911. I have a feeling only Loose Change engineers will support your inside job fantasy. What did 60 minutes say? This super important stuff. If it were not a fantasy based on nonsense. That is why no one takes your inside job claims serous.

What was wrong with what you have been presented? Why do you have go all Balsamo, try to take it private? Is the truth only for the few? Was it thermite or silent explosives, in the fantasy inside job? Are these questions too technical?
 
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enik said:
Yes I did. I even offered to email it to you. I am even willing to take it offline and discuss the differences between our two analyses.
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I asked you to attach it to the thread. Creating a report and then not doing anything with it is worthless. Why don't you attach it to a post in the thread, like I did with my report?

You did provide me with a read out of your analysis, but you don’t want to answer a few questions nor do a simple hand calculation on your first case.
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Oi, you've already done it, I've already done it. It's very simple. You know I'm getting a deflection value of about 1/0.8 higher than you and what a simple analysis doing Euler-Bernoulli theory would show. I've already stated that this is due to me using AISC Appendix 7 in RISA. You've posted in a manner that shows you read that statement. Why are you bringing it up again? Have you read through AISC Appendix 7 and have a question about why it applies? Or are you intentionally trying to waste my time?

It would be nice to know more about the RISA software and why you are getting higher values than me, but I don’t want to get into an argument on who has the better FEA software in this thread.
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I've already told you why you're getting higher values than me.

It doesn't matter who has "better" software. RISA performs linear static and dynamic problems perfectly well with 9 d.o.f. 1D Timoshenko elements. It can do the work that is required.

What is slightly relevant is whether either of us understand what is going on under the hood of our various analysis tools. Now, I can duplicate the analysis that RISA did, with FEA, from RISA. I can do P-Delta analysis by hand.
 
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DGM said:
At Loose Change Forum? Ask JFK (if he's still around) about my account, he attacked me on my first post. This was 4 years ago, is it still around?
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It still exists, but only as a ghost town. There's no one posting there, to ask anything. Even MM left the building.:cool:
 
jaydeehess said:
scroll up to the picture in beach's post.

You aren't denying inward bowing are you?

If not then tell me, if this is not a result of pull in on those columns then what did cause it?
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I am asking to identify the columns numbers and floors where the bowing was. I am not denying it...

I believe the bowing is BUCKLING and from excessive loads coming from the hat truss which was carrying 10 floors (portion of) in the core... The IB direction was caused by a single sagging floor being attached to the INSIDE of the columns and the IB was limited to a single floor ht because it was restrained be floors below and above...

The IB was below the outriggers of the hat truss and would occur OPPOSITE to the side where the plane damaged the core... that side where the damage was no longer carrying axial loads.

Got it?
 
JSanderO said:
I am asking to identify the columns numbers and floors where the bowing was. I am not denying it...

I believe the bowing is BUCKLING and from excessive loads coming from the hat truss which was carrying 10 floors (portion of) in the core... The IB direction was caused by a single sagging floor being attached to the INSIDE of the columns and the IB was limited to a single floor ht because it was restrained be floors below and above...

The IB was below the outriggers of the hat truss and would occur OPPOSITE to the side where the plane damaged the core... that side where the damage was no longer carrying axial loads.

Got it?
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I'd have to go back to the reports and find those numbers, why are they important?

Not visualizing how this occurs.

The hat truss us pushing down on the side opposite the impact damage because......
The upper portion, inclusing roof and hat truss were leaning in the direction of the imapcts were they not? That would tend to put the hat truss into position of higher probability to have the opposite side of the tower perimeter in tension rather than compression. I don't see how massive compression would occur nor why a single sagging floor is probable.

A single sagging floor would seem pretty much a special condition and the ejections that MT talks of would support a position that many floors were in trouble and failed.

I will agree with one thing though. The trusses made sure that any bowing of perimeter columns would be inward as long as they were still attached to the columns.

ETA: I also agree that in hindsight the long span open floor design is not a safe one, at least not w/o extra diagonal bracings in core and perimeter. WTC7 was unigue in its beams not constraining all girders in opposing directions, a weak point.
 
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enik said:
Yes I did. I even offered to email it to you. I am even willing to take it offline and discuss the differences between our two analyses.

You did provide me with a read out of your analysis, but you don’t want to answer a few questions nor do a simple hand calculation on your first case. It would be nice to know more about the RISA software and why you are getting higher values than me, but I don’t want to get into an argument on who has the better FEA software in this thread.
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Could you please lay out your full inside job theory here?
 
jaydeehess said:
I'd have to go back to the reports and find those numbers, why are they important?

Not visualizing how this occurs.

The hat truss us pushing down on the side opposite the impact damage because......
The upper portion, inclusing roof and hat truss were leaning in the direction of the imapcts were they not? That would tend to put the hat truss into position of higher probability to have the opposite side of the tower perimeter in tension rather than compression. I don't see how massive compression would occur nor why a single sagging floor is probable.

You're not serious here are you? If there was substantial damage on one side... the loads would be redistributed to the undamaged columns of the facade... the truss would be the mechanism for moving core loads as/when the core cols failed or were destroyed. This process continued from HEAT WEAKENING which added more and more load via the hat truss to the facade.

When the core completely failed the area above was all hanging from the hat truss which was 100% of the loads on the facade which had lost 15-20% of the columns and it buckled.

A single sagging floor would seem pretty much a special condition and the ejections that MT talks of would support a position that many floors were in trouble and failed.

The facade peeled off because the floors were no longer holding them in place.. they were more and more unstable as the unbraced length grew as the floors collapsed down inside.

I will agree with one thing though. The trusses made sure that any bowing of perimeter columns would be inward as long as they were still attached to the columns.

Bingo

ETA: I also agree that in hindsight the long span open floor design is not a safe one, at least not w/o extra diagonal bracings in core and perimeter.

Many issues which led to unstoppable floor collapse and bracing wasn't one of them.


WTC7 was unigue in its beams not constraining all girders in opposing directions, a weak point.

Nothing to do with the initiation of the collapse... it was transfer structures which failed and likely the field assembled connection splices which failed first.
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look at the engineering drawings

A/B
 
enik said:
And yet this entire challenge is trying to support the NIST hypothesis. Why don't you give it a try.
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No well-researched, peer-reviewed hypothesis requires the support of people (like me or you) who are unqualified to evaluate its particulars.

You may refuse to believe, on principle, any firmly established theory on the basis that you don't understand it, but to me accepting it as true is worth the nearly insignificant risk that there might be some other explanation...especially since no one has been able to offer a plausible alternative.
 
JSanderO said:
The IB was below the outriggers of the hat truss and would occur OPPOSITE to the side where the plane damaged the core... that side where the damage was no longer carrying axial loads.

Got it?
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You got this wrong. The hat truss would transfer the loads of the damaged perimeter wall to the core and along the two adjacent perimeter walls. The core (undamaged part) would also carry some additional load and act as a pivot point. The opposite perimeter wall would be carrying less load and could even go into tension.

Ever play on a see-saw? ;)
 
DGM said:
You got this wrong. The hat truss would transfer the loads of the damaged perimeter wall to the core and along the two adjacent perimeter walls. The core (undamaged part) would also carry some additional load and act as a pivot point. The opposite perimeter wall would be carrying less load and could even go into tension.

Ever play on a see-saw? ;)
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Ha? That sounds like double talk...

The core acts *a* pivot point? Are you certain of this?
 
DGM said:
You got this wrong. The hat truss would transfer the loads of the damaged perimeter wall to the core and along the two adjacent perimeter walls. The core (undamaged part) would also carry some additional load and act as a pivot point. The opposite perimeter wall would be carrying less load and could even go into tension.

Ever play on a see-saw? ;)
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The core columns shortened slightly over time due to heating effects.

This would increase loads on the ext columns dircetly below the hat truss outriggers (on all 3 sides) as SanderO states AND NIST describe.....
 
Seymour Butz said:
The core columns shortened slightly over time due to heating effects.

This would increase loads on the ext columns dircetly below the hat truss outriggers (on all 3 sides) as SanderO states AND NIST describe.....
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What do you mean they shortened over time from heating effects?

I would think the heat WEAKENED them not shortened them. Think of it conceptually as if the columns were becoming thinner and thinner and incapable of supporting the loads on them... something like the attached cartoon... load capacity was driven away by heat
 

Attachments

JSanderO said:
What do you mean they shortened over time from heating effects?

I would think the heat WEAKENED them not shortened them. Think of it conceptually as if the columns were becoming thinner and thinner and incapable of supporting the loads on them... something like the attached cartoon... load capacity was driven away by heat
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They were being compressed. The core was not hanging off the hat-truss. The additional load from the damaged exterior wall was being redistributed to the core and the remaining exterior walls. The hat-truss was keeping it all rigid (more or less). As the core was compressed the loads increased on the remaining 3 walls. Not exactly evenly, the load was higher toward the damaged area.
 
DGM said:
....As the core was compressed the loads increased on the remaining 3 walls. Not exactly evenly, the load was higher toward the damaged area.
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Take care to not conflate two reasons for core load changes - they are in opposition.

1) If the core was weakening due heat (or CD) it would be losing load capacity and carrying less; BUT
2) If the core was getting "compressed" it would be because of being subjected to more load.

Similarly the total load on the damaged side would be getting less whilst the load on the few specific "Columns which will be next to fail" would be increasing.

Then the loads will not transfer to the opposite side of the building to add to existing load. Reasons can be seen from this very simplified model. It is more extreme than Twin Towers set up BUT it illustrates the principles - excuse the poor quality of the hand drawing.
cutcols3.jpg


A "three rows of columns" simplification to illustrate a principle. at rest the Top Block weight of 400 is split (say) 100/200/100 across rows A, B and C. (Labelled "Case 1A")

Then cut out row "C". If the top block is rigid the loads go to 0/400/0 - should be obvious why in this simple model. (Labelled "Case 2A")

BUT the reality is that the Top Block is flexible. So it 'droops' or sags over the "core" of Row "B" - because the row "C" has been removed. (Labelled "Case 2B") So the sagging causes the Centre of Mass to move outside the support - and tilt follows. If it really was that simple model it would start to put tension into Row A - and increasing the "core" row B force over the already doubled value of 400.

That example is more extreme than WTC reality on 9/11 but it starts to put some numbers on "load redistribution". And starts to show why load redistribution is not a linear uniform re-allocation. If you cut 25% of columns you do not get 33.3% increase in load uniformly across the remaining columns. What actually happens depends largely on which columns cut/which columns remain and where they are spatially distributed. Without going into the complexities it is analogous to Moment of Inertia/Section modulus considerations.

[/End Structures301 ;)
 
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