New guy here: Questions for official hypothesis

Sizzler said:
Right, but the core offered no additional resistance to the floor truss connections for the majority of the floors.

and the fact that some core columns remained for a few more seconds seems to violate the "crush down" mechanism decribed by bazant.
Click to expand...

I think you'll find that the connections at the core and at the perimeter were very similar. a load that shearsone will shear the other.
And remember, Bazant's model is simplified. They are looking basically at energy and momentum, not specific loading.
 
The core had just been hammered by the top section. The hat truss and core columns above must have hammered the core into the ground. I know it was ripped apart on top which must have cause an uneven load. Add some wind and the massive leverage of the 50 story, battered and brused core could stand no more. The core was no more than a punch drunk prize fighter struggling to stand in the 12th round.

The perimeter kept the core from leaning over and the core held the perimeter up like a shield. With the perimeter, the building swayed in the wind. Without the perimeter, the leverage would have been too much even without the events on 911. That's the way it was designed.
 
Last edited:
rwguinn said:
I think you'll find that the connections at the core and at the perimeter were very similar. a load that shearsone will shear the other.
And remember, Bazant's model is simplified. They are looking basically at energy and momentum, not specific loading.
Click to expand...

Right, both connections could have failed, I understand that,

What I don't understand is;

How can the actual core itself be a part of the progressive collapse?

Floors are horizontal so I understand how each floor could fail one by one in a progressive manner.

But the core is vertical, so I see this being much more resistant that the floor trusses.

If I built a model of the WTC using dry pasta strands, it seems that the vertical core strands would be more resistant that the horizontal strands.

You guys have helped me out to understand a progressive collapse, floor by floor by floor, but I don't understand how the core columns failed too. Because they are vertical and much stronger than the floor truss connections, it seems they would be much more resistant to any kind of progressive collapse.

I can now imagine a progressive collapse thanks to you wonderful help, but I can't imagine how the core columns fail in this scheme too.
 
Last edited:
WildCat said:
It wasn't an "independent structure". The core columns were incapable of standing on their own. In fact, in WTC construction photos you can see how they had to apply temporary cross-bracing to the core columns until the structure around them was completed.
Click to expand...
Incapable of standing on their own?
Then architect must be lying when he says
"Parts of the core indeed stood for a few seconds after the rest of structure collapse, but were inherrently unstable - see my note about the interlinked nature of the structure previously."
 
yes well if I had a broken hip, I could probably stand on it for a few seconds, but that does not mean I can "stand on my own" in the practical sense, does it?

TAM:)
 
beachnut said:
Still enough mass to have too enough energy for, global collapse as seen on 9/11. Due to impact and fire. Darn, what is your point using your estimate for mass when it makes no difference, in fact you could explain more what changes this makes to the other assumptions made for collapse initiation. What would less mass mean for the strength of the less massive steel sections. As in did the energy of the more massive steel structure you are now saying is less decrease the needed energy to overcome and destroy? Is your estimate a double edge sword, you say less and the energy to destroy gets less; or you want it both ways, less and more?

It appears the mass is more than enough to start a global collapse. What do you say? Or do you have some evidence to prove something here?
Click to expand...

You have accused me a number of times of "shaving mass" as you put it this time. You still have not pointed out any significant errors in my paper, which makes it obvious to everyone that this is a bogus claim.

The simple fact that you have not grasped is this:

The strength of the building is dependent mostly on the columns. We know the dimensions from the NIST SAP model data. The mass of the building does not change this. Thus the energy consumed in failing the columns is proportionally higher relative to the available potential energy and will affect collapse times and may arrest collapse.

I have recalculated Bazant's overload ratio with the correct values for C, Po and m. My preliminary result is 1.8 as compared with Bazant's 31, which would indicate collapse progression. There are a few issues remaining, but I'll post it as soon as I feel like it's ready for prime-time.
 
Sizzler said:
Right, both connections could have failed, I understand that,

What I don't understand is;

How can the actual core itself be a part of the progressive collapse?

Floors are horizontal so I understand how each floor could fail one by one in a progressive manner.

But the core is vertical, so I see this being much more resistant that the floor trusses.

If I built a model of the WTC using dry pasta strands, it seems that the vertical core strands would be more resistant that the horizontal strands.

You guys have helped me out to understand a progressive collapse, floor by floor by floor, but I don't understand how the core columns failed too. Because they are vertical and much stronger than the floor truss connections, it seems they would be much more resistant to any kind of progressive collapse.

I can now imagine a progressive collapse thanks to you wonderful help, but I can't imagine how the core columns fail in this scheme too.
Click to expand...
Did you read what I wrote? If so, what's wrong with it?
 
Last edited:
Parts of the core indeed stood for a few seconds after the rest of structure collapse.

If this is true the whole global collapse theory flies out the window.
 
Sizzler said:
Right, both connections could have failed, I understand that,

What I don't understand is;

How can the actual core itself be a part of the progressive collapse?

Floors are horizontal so I understand how each floor could fail one by one in a progressive manner.

But the core is vertical, so I see this being much more resistant that the floor trusses.

If I built a model of the WTC using dry pasta strands, it seems that the vertical core strands would be more resistant that the horizontal strands.

You guys have helped me out to understand a progressive collapse, floor by floor by floor, but I don't understand how the core columns failed too. Because they are vertical and much stronger than the floor truss connections, it seems they would be much more resistant to any kind of progressive collapse.

I can now imagine a progressive collapse thanks to you wonderful help, but I can't imagine how the core columns fail in this scheme too.
Click to expand...

Most of the models assume that all of the impact forces go into the columns (vertical members) and are distributed evenly among them because that is the most optimistic for survival of the structure. In other words, if you can shown failure with uniform distribution, then the building will fail under any other distribution. (See Bazant's simple analysis.)

So every column in the upper part hits the column below it in the lower part. If most the columns in the lower part fail, global collapse will ensue. One issue not usually mentioned by JREFers is that the upper columns probably failed first which makes the calculations very messy with the possible outcome of only a partial collapse. My opinion is that until we do the messy calculations, we will not know.
 
Tweeter said:
Parts of the core indeed stood for a few seconds after the rest of structure collapse.

If this is true the whole global collapse theory flies out the window.
Click to expand...

Welcome Tweeter,

It depends what you mean by global collapse theory. The entire building collapsed.
 
GregoryUrich said:
You have accused me a number of times of "shaving mass" as you put it this time. You still have not pointed out any significant errors in my paper, which makes it obvious to everyone that this is a bogus claim.

The simple fact that you have not grasped is this:

The strength of the building is dependent mostly on the columns. We know the dimensions from the NIST SAP model data. The mass of the building does not change this. Thus the energy consumed in failing the columns is proportionally higher relative to the available potential energy and will affect collapse times and may arrest collapse.

I have recalculated Bazant's overload ratio with the correct values for C, Po and m. My preliminary result is 1.8 as compared with Bazant's 31, which would indicate collapse progression. There are a few issues remaining, but I'll post it as soon as I feel like it's ready for prime-time.
Click to expand...
Your work will confirm there were no explosives used on 9/11. Sounds good to me.
 
Last edited:
FactCheck said:
Did you read what I wrote? If so, what's wrong with it?
Click to expand...

Yes I read it, but it didn't really answer my question.

Sorry it is probably my fault.

Let me try again.

I understand how progressive collapse works now. If the initial floor can't resist collapse, then none of the other floors will be able to resist collapse either. The floors would all collapse no matter how many floors there were.

I am now satisfied with the kind of collapse mechanism.

However the WTC towers were not just horizontal floors stacked on top of each other.

In the middle were 47 strong, interconnected core columns. These are vertical not horizontal.

So I can't imagine how the core columns also progressively fail too.

The structure of the core does not match a progressive collapse scheme.

So although the floors may been unable to arrest collapse, why did the core columns add no additional strength?
 
Tweeter said:
Parts of the core indeed stood for a few seconds after the rest of structure collapse.
Click to expand...
Kinda important, that word.

If this is true the whole global collapse theory flies out the window.
Click to expand...
Well, seven above-grade stories of part of the north tower core remained standing until it was torn down. 16 people survived in it. They do believe that the building globally collapsed, without the use of explosives.
 
Last edited:
Sizzler said:
Thanks a lot for all the information thus far.

I'm still reading what gravy posted.

A lot of you have expressed the idea that the collapses would have naturally proceeded to the ground after collapse initiation.

This might be clear to those of you that are experts, but, I am in no way an expert. Thus, I've asked for a paper describing the event. Gravy directed me to the right places. Thanks again:)

_______________________________

To address those that are suspicious of my intentions;

I'm Canadian. I recently learned about this debate via a friend (3 months ago). He passed zietgiest (sp??) over to me and I gave it a watch. I was skeptical because it wreaked of bogus conspiracy, but nonetheless, I was very curious.

I did some of my own research on the net and found a lot of disinformation in the film.

for example;

-quote mining
-squibs
-columns cut on an angle
-"pull it"
-etc etc etc etc.

I remained curious though because I was not familiar with the specifics of the official story and certain aspects of the alternative theory.

I am currently going through my own process of understanding.

I came here and posted because it is the best blog site I have found thus far for this topic.

So anyway, I hope you guys understand where I am at.
Click to expand...



Why should anyone care what you think.
 
Sizzler said:
Yes I read it, but it didn't really answer my question.

Sorry it is probably my fault.

Let me try again.

I understand how progressive collapse works now. If the initial floor can't resist collapse, then none of the other floors will be able to resist collapse either. The floors would all collapse no matter how many floors there were.

I am now satisfied with the kind of collapse mechanism.

However the WTC towers were not just horizontal floors stacked on top of each other.

In the middle were 47 strong, interconnected core columns. These are vertical not horizontal.

So I can't imagine how the core columns also progressively fail too.

The structure of the core does not match a progressive collapse scheme.

So although the floors may been unable to arrest collapse, why did the core columns add no additional strength?
Click to expand...
I'm having trouble following you, here.
What additional strength are you speaking of? Once the floors had sheared away, where is the lateral stability going to come from?
Remember--the columns did not only support the floors-the floors stabilized the columns. Oncwe the floors went, the columns were merely along for the ride

Load paths. Remember what Architect said about changing the load paths?
 
Sizzler said:
Yes I read it, but it didn't really answer my question.

Sorry it is probably my fault.

Let me try again.

I understand how progressive collapse works now. If the initial floor can't resist collapse, then none of the other floors will be able to resist collapse either. The floors would all collapse no matter how many floors there were.

I am now satisfied with the kind of collapse mechanism.
Click to expand...

Yes, I understood that...

However the WTC towers were not just horizontal floors stacked on top of each other.

In the middle were 47 strong, interconnected core columns. These are vertical not horizontal.

So I can't imagine how the core columns also progressively fail too.
Click to expand...

I'm not sure progressive collapse is what you would call it. They leaned over at the bottom of the pile due to leverage. You know, that thing which helps you tighten the nuts on your car. The longer the wrench, the more leverage you have. There was 50 stories worth of leverage exerted on the core at the top of the pile. Parts of the core were recorded on video leaning over but most of it moved over and fell all at once.

The structure of the core does not match a progressive collapse scheme.

So although the floors may been unable to arrest collapse, why did the core columns add no additional strength?
Click to expand...
As I understand your question, the floors were NOT sitting on the core columns. They were connected with about the same comparatively weak connections as the perimeter connections. So they wouldn't add strength to the building as a whole. They wouldn't add anything to the core either. In fact I would predict the floors being ripped off so violently had a negative effect on on the core. And I don't understand why you are having trouble with the massive hat truss with core columns connected slamming into the core 100 times. Regardless of the cause of collapse the core would be hammered. You seem to be thinking of a pristine core...
 
rwguinn said:
I'm having trouble following you, here.
What additional strength are you speaking of? Once the floors had sheared away, where is the lateral stability going to come from?
Remember--the columns did not only support the floors-the floors stabilized the columns. Oncwe the floors went, the columns were merely along for the ride

Load paths. Remember what Architect said about changing the load paths?
Click to expand...

So you mean the floors failed first, and then the core columns failed next because they were unsupported?
 
I'm really troubled by the use of words here.. He calls the NIST report an "Official story" and the conspiracy story an "Alternative theory." My antenna just went up...
 
tsig said:
Why should anyone care what you think.
Click to expand...

Good question.

I posted my own personal story because people thought I was suspect. I didn't want to ignore it, so I thought I would address it.

Anyway, I share the same question you have but others on this board have expressed an interest in my beliefs prior to posting on this board.

Therefore I replied.
 
You must log in or register to reply here.

Back
Top Bottom