Moderated Steel structures cannot globally collapse due to gravity alone

[Gravy]

...Yah, no. Progressive collapse was well defined in building code well before 9/11 for a reason.

This was true in the UK (after the Ronan Point collapse), and in some other countries, but not in the US, where codes requiring "structural integrity" were in place, but progressive collapse wasn't specifically addressed. The principle, of course, was well known and studied by engineers around the world. There's a section with papers about engineering to resist progressive collapse at my website.

 

[Christopher7]

The previous section was:
Velocity of Air Ejected from the Tower
and the following section is:
Energy Dissipated by Comminution (or Fragmentation and Pulverization)

This seems to be another example of your adjacent=identical fallacy. These are different sections.

That's what I said. I was just pointing out that:

They do not offer another mechanism for the "large steel pieces".

Nor do they claim that the large steel sections were ejected by air pressure.

Yes they do. Is English your first language?

Resisting Forces Due to Ejecting Air and Solids
The air mass within the confines of one story, which is . . . , gets accelerated from 0 to velocity va as it exits the tower perimeter. The kinetic energy acquired by the escaping air of one story just outside the tower perimeter is . . . . where . . . = initial volume of air within the story.
The energy dissipated by viscosity of flowing air and by boundary friction is estimated to be negligible. Therefore, virtually all of the kinetic energy of escaping air must be supplied by gravity, . . .
<snip>
The average over-pressure of air within the tower is . . . .
The pressure peaks near the end of squeezing of a story are doubtless much higher, as already mentioned, and thus must contribute to the break up of many floor slabs (theoretically, the pressure in a thin layer of viscous gas between two colliding parallel flat slabs approaches infinity at the end).

The mass that is shed from the tower, characterized by k-out, exits at various velocities ranging from nearly 0 to almost either the air ejection velocity, for fine dust, or to roughly z˙, for large steel pieces.



They are discussing the role of air pressure.
They do not offer another mechanism for the ejection of the "large steel pieces".
Find one or stop saying one exists.

Where do they allow for the energy necessary to hurl numerous 4 ton framing sections up to 600 feet?

 

[Christopher7]

Chris, I took the time to assemble a website that answers exactly these kinds of questions. Is there any reason that you haven't availed yourself of the wealth of information there?

On page 1 of the engineering section:

Why didn't the towers, or the upper portions of them, topple over?

​

Why didn't the upper part pivot about it's base? See Bazant & Zhou (2001) Appendix II
Eduardo Kausel (MIT): Why the Towers didn't fall like trees
Frank Greening: An analysis of the tipping of the upper section of WTC 2 (PDF)
A simple graphic explanation of why the top of the south tower didn't fall to the side.
Physicist Dave Rogers on tipping of tower tops.
Structural engineer "Newton's Bit" on "tipping"

I have read some of your diatribes, debunked Greening's garbage and debated with Newtons Bit and Dave Rogers enough to know that they are not what they say they are.

Don't try to send me on a wild goose chase.

If you have something relevant to say, say it.

 

[Gravy]

Don't try to send me on a wild goose chase.

If you have something relevant to say, say it.

You refuse to read the explanations of why toppling didn't occur? You are a Basking Shark in a sea of ignorance. Back on ignore you go, and good riddance.

 

[Architect]

This was true in the UK (after the Ronan Point collapse), and in some other countries, but not in the US, where codes requiring "structural integrity" were in place, but progressive collapse wasn't specifically addressed. The principle, of course, was well known and studied by engineers around the world. There's a section with papers about engineering to resist progressive collapse at my website.

The Eurocode has been updated to require greater resistance to dispropportionate progressive failure in light of post-911 research. Which means, of course, that lots of learned engineers have pored over the drafting and are content with the underlying issues. Something the Truther Movement always seem to overlook.

 

[Architect]

I have read some of your diatribes, debunked Greening's garbage and debated with Newtons Bit and Dave Rogers enough to know that they are not what they say they are.

Really? I can't say that I arrived at the same conclusion. What exactly in their expertise do you feel them to be misrepresenting?

 

[Christopher7]

You refuse to read the explanations of why toppling didn't occur? You are a Basking Shark in a sea of ignorance. Back on ignore you go, and good riddance.

Bazant wrote that 9-13-01 and updated on 9-22-01

This is not science. This is pure conjecture. He doesn't have any data.

Appeal to authority denied.

Speak for your self. Don't glibly pass the buck.

* * * * *
Do you have a response to this:

Newton's first law says an object in motion will remain in motion unless acted on by an external unbalanced force.

The top section was in motion to the side and down.
Both motions continued as the collapse progressed.
The side motion would continue and the top section would fall off the side of the building unless some external balancing force were applied.

* * * * *
or are you just a blow hard that blows by now and then to make a sarcastic comment and leave without contributing anything specific like a particular relevant quote from one of the sources you claim makes your point.

 

[peteweaver]

If downward force is greater than tilt, and the structure below cannot arrest the collapse, there is insufficient resistance and the load above the structural failiure will cause progressive collapse.

Why can't the troofers realise that ?

 

[Dave Rogers]

I have read some of your diatribes, debunked Greening's garbage and debated with Newtons Bit and Dave Rogers enough to know that they are not what they say they are.

The final clincher, for me, that a conspiracy theorist is delusional, is when he or she makes personal statements about me that I know to be false. So, Chris, so that I can finally dismiss everything you have ever said as the product of a malfunctioning mind, would you please state what it is that I say I am and you know me not to be?

Dave

 

[Heiwa]

I look fwd to a reply to #515 to finish the discussion.

 

[GStan]

Bazant wrote that 9-13-01 and updated on 9-22-01

This is not science. This is pure conjecture. He doesn't have any data.

Appeal to authority denied.

Speak for your self. Don't glibly pass the buck.

* * * * *
Do you have a response to this:

Newton's first law says an object in motion will remain in motion unless acted on by an external unbalanced force.

The top section was in motion to the side and down.
Both motions continued as the collapse progressed.
The side motion would continue and the top section would fall off the side of the building unless some external balancing force were applied.

* * * * *
or are you just a blow hard that blows by now and then to make a sarcastic comment and leave without contributing anything specific like a particular relevant quote from one of the sources you claim makes your point.

Gravity pulling straight down is the only force, the whole time. The tilt to the side is created by a hinge (the imbalance between damaged and intact support columns in the impact zone). Even though its moving to the side, gravity is still the force applied. When the hinge breaks (the intact columns can't sustain the additional weight), the mass is all falling more or less, straight down, by force of gravity.

And the sporadic lateral ejections are the results of collisions between pieces of the falling, breaking mass (not explosives), which would be expected in a collapse that released the amount of energy it did. I don't know what the exact amount is but I'm sure you've seen Beachnut post it several hundred times in various threads here. Its alot.

Do you really not know this basic stuff or are you just pretending not to know it?

 

[tfk]

No, pls read my article at http://heiwaco.tripod.com/nist3.htm to find the answer. Topic is steel structures + gravity, etc.

But yes, no collapse occurs ever of lower object. It may be crushed down from top down. But that is not a collapse. Collapse is something else.

And again, topic is what happens to the upper object. According NIST, Bazant, etc, it should remain intact. It is however impossible, if it attempts to crush down the lower object just assisted by gravity.

And that's why the NIST/Bazant theory is nonsense.

I think it is time to lock this thread, moderator.

Heiwa,

"Crush down" is different than "collapse"...?

Ahhh, you might have defined your terms sooner. Why don't you give your definition now.

If it "collapses", floor by floor by floor, from the contact interface between the lower & upper segment to the ground, just like the WTC towers did, you do not consider this a collapse?? Seems to me to be a pretty arbitrary definition.

You say the lower segment will NEVER collapse. I disagree. Suppose that you have a weak point on the ground floor. This weak point was strong enough to support the structure above statically. But, due to the combination of the static load and dynamic load, this point may well have a very high STRESS (the factor that determines failure, not force) level that exceeds its strength.

Then, by what I am presuming to be your definition of "collapse", this structure could indeed collapse from this weak point, even if a progressive crush down does not start from the top most floor. There is no mechanical theory that says that a smaller segment can never cause a collapse in a larger lower structure.

It all comes down to local stresses.

tk

 

[Dave Rogers]

Yes they do. Is English your first language?

Why do you keep posting quotes that don't support your argument, and claiming that you do? Everyone can see it except you. Nowhere in this passage is it asserted that large sections of steel are ejected by air pressure. If you want clarification, ask the people who wrote it. I've told you where to find them.

Dave

 

[Christopher7]

The final clincher, for me, that a conspiracy theorist is delusional, is when he or she makes personal statements about me that I know to be false. So, Chris, so that I can finally dismiss everything you have ever said as the product of a malfunctioning mind, would you please state what it is that I say I am and you know me not to be?

Dave

You guys constantly call me delusional, liar, coward etc. but then you get all indignant when I say what I think about you. Put it in a sock.

You claim to be a physicist. do you have one of these?

Seriously folks,

Show your credentials or stop claiming to be anything other than an anonymous smartass.

 

[e^n]

I look fwd to a reply to #515 to finish the discussion.

I look forward to your response to #484

Christopher7. You are resorting to some pretty silly tactics in this argument. No matter how much you bold certain sections, your interpretation is not supported by this paper. I pointed out how these are handled in the same post I have linked above, but now you have resorted to trying to poison the well by claiming Newtons Bit, Dave Rogers etc are lying about their credentials I see no point in continuing.

I doubt you can point out errors in their work, if you apply the same technique as you do to the passage you quote then I think it is likely you have formed an interpretation of their work, and resist changing this even if informed you are incorrect.

I don't mean to slander you, and I am not accusing you of anything directly. I just want to point out that you are unable to see that you are wrong in this immediate case, and this may be a sufficient explanation as to why you disagree so vehemently with people who have demonstrated their expertise.

edit:

Show your credentials or stop claiming to be anything other than an anonymous smartass.

Please state your exact criteria for what credentials you will accept. I would not be happy posting my credentials (if i had any that were relevant) until I was assured that no goalposts could be moved.

 

[Bananaman]

Chris7

Put it in a sock.

I think the phrase you're looking for is 'put a sock in it'. Only 5 words and you get 4 of them in the wrong order. Sort of a metaphor for everything you post.

OK, carry on crucifying him, guys.

Bananaman.

 

[GStan]

You guys constantly call me delusional, liar, coward etc. but then you get all indignant when I say what I think about you. Put it in a sock.

You claim to be a physicist. do you have one of these?

[qimg]http://img6.imageshack.us/img6/967/aircraftcourseorg800zc2.jpg[/qimg]

Seriously folks,

Show your credentials or stop claiming to be anything other than an anonymous smartass.

Ok, so you are credentialed and qualified to talk about Air Force Mishaps. Have you posted in any threads here about Air Force Mishaps in which your expertise or credentials were questioned?

 

[e^n]

Ok, so you are credentialed and qualified to talk about Air Force Mishaps. Have you posted in any threads here about Air Force Mishaps in which your expertise or credentials were questioned?

I believe that is Beachnut's certificate

 

[GStan]

Chris7


I think the phrase you're looking for is 'put a sock in it'. Only 5 words and you get 4 of them in the wrong order. Sort of a metaphor for everything you post.

OK, carry on crucifying him, guys.

Bananaman.

<spits coffee on keyboard>

 

[Christopher7]

Why do you keep posting quotes that don't support your argument, and claiming that you do? Everyone can see it except you. Nowhere in this passage is it asserted that large sections of steel are ejected by air pressure. If you want clarification, ask the people who wrote it. I've told you where to find them.

Dave

I found and read their papers. There is nothing there about the ejected debris other that the section about air pressure. No clarification needed.

Can you find where Bazant or Greening account for the ejected debris?

Post the part where either one addresses this issue or stop claiming that they do.