By your reply you expose the falseness of your assertion in your reply. Also you could notice that many are indeed interested because they continue to reply. No wonder you fell for the official nonsense.

William Seger

(11,045 posts)

3. If you really understood what Dusterwald is saying..

Reply to wildbilln864 (Original post)

Tue Sep 9, 2014, 08:59 PM

Sep 2014

... you might be able to figure out on your own what's wrong with it. On the other hand, if you're impressed by what he's saying, then you must not really understand it. That's because what he's saying has virtually nothing to do with how either WTC7 or the towers actually collapsed.

The basic philosophy of the building code in the last 75 to 80 years has been to ensure ductile failure of the members to provide for the public safety. Under this philosophy, members that are overloaded will deform elastically, within the elastic range of the material, with increasingly large deformations and deflections and after the yield point the members reach it will go into a plastic range, where the steel stretches without any increase in load.
*snip*
The actual failure mode of the structure showed that the connections were failing at over 400 connections per second for building number 7 and a similar number for buildings 1 and 2. This is in direct physical contradiction to the design of the building which ensured that the members went through large elastic and plastic deformations before the connections would fail. In fact the connections were designed with a safety factor of 1.5 to 3 times the failure load for the member. This ensures that the member will always fail first, first in an elastic mode and then a plastic mode, and after the member has failed then the connection would still be intact.

What Dusterwald is saying about "members that are overloaded" is true IF by "overloaded" he means, for example, that you kept adding weight on a steel beam until something failed. In that case, all he is saying is that in the design for gravity loading, the shear strength of the connections should have a larger margin of safety than the beams they are holding, so with gravity overloading, a beam would be expected to bend before its connections gave way. True enough, but so what if we're talking about WTC collapses? Your first clue that Dusterwald's trolley is off the tracks should come when you realize that in the towers, the statement is meaningless because the predominant failure modes were the result of impact loading and momentum transfer, and in the case of WTC7, the progressive failure was primarily caused by connections failing with moment overload when one end of a beam fell, not overload in shearing forces. There is no logical reason to expect those failure modes to happen slowly. The repeated claim about 400 connections per second failing is so irrelevant that it's hard to comprehend why Dusterwald thinks it matters, except that his faulty premises and invalid logic have apparently led him to erroneously conclude that the collapses should have happened slowly. Most engineers seem to understand that either a natural collapse will happen rapidly or it will not happen at all, so if you start with the conclusion that it shouldn't have happened at all and try to justify that assertion by saying it happened too rapidly, you should expect the argument to be met with a lot of eye rolling.

So the failure of all these connections as the primary means of structural failure is inconsistent with a natural gravitational collapse and indicates the presence of other agents which would dismember these connections.
*snip*
But this failure mechanism would require that the connections would have to fail at this tremendous rate, for building number 7, 400 connections per second, and this would not be physically possible for a gravitational collapse – there had to be some other agent responsible for dismembering all the members from their connections and from each other.

As with David Chandler's pseudo-analysis of the tower collapses, if you try to analyze a dynamic situation as if it were static, you will get the wrong answers every time. The "other agents" which Dusterwald seems to be oblivious to include impact loads and moment loads which the buildings were simply not designed to withstand. As I've said before, most structural engineers don't seem to have a problem understanding and explaining why the collapses were rapid, and Dusterwald's only challenge to their explanations is based on faulty premises, invalid logic, and naked assertions.

Building number 7 descended in free-fall for the first 100 feet which means that there was absolutely no resistance for the descent whatsoever, and this is inconsistent with the energy redistribution that would be required from the descending mass to the remaining structure.

Another faulty premise: The free fall was not "the first 100 feet." The first 7 feet were at less than free fall because, indeed, the gravitational energy was being redistributed. The 100 feet of free fall came after columns buckled and broke, so here's another person with a structural engineering background but who can't figure out that broken columns provide "absolutely no resistance," yet you expect people to be impressed with their expertise.

In my 37 years of experience as a structural engineer I've never seen modes of failure such as have been exhibited in the case of these buildings and that's why I feel that we need a new, independent investigation to explain the destruction of these three buildings.

Or, maybe he could ask his colleagues to explain it to him. As it stands, Dusterwald's personal lack of understanding is not a reason for a new investigation, and furthermore there's no reason to think his understanding would be improved by another investigation. The reason that the vast majority of the engineering community are not compelled by these calls for a new investigation is that the objections to the first one are so lame.

wildbilln864

(13,382 posts)

4. fail again Seger!

Reply to William Seger (Reply #3)

Tue Sep 9, 2014, 10:12 PM

Sep 2014

William Seger

(11,045 posts)

5. Exactly

Reply to wildbilln864 (Reply #4)

Tue Sep 9, 2014, 11:05 PM

Sep 2014

Once again, Gage's "expert" fails to demonstrate that he knows what he's talking about. Looks like a pattern to me -- almost as if that's a requirement to be one of Gage's "experts."

wildbilln864

(13,382 posts)

6. yes 4 decades of experience...

Reply to William Seger (Reply #5)

Fri Nov 21, 2014, 07:58 PM

Nov 2014

and he doesn't know what he's talking about according to you but you do with no experience at all! That's so fucking rich! He's not Gages expert, he's just an expert! Do you even understand how utterly ridiculous you sound?

William Seger

(11,045 posts)

9. Did you even read what I wrote?

Reply to wildbilln864 (Reply #6)

Sat Nov 22, 2014, 01:02 PM

Nov 2014

What he talks about in this video has almost nothing to do with what actually happened in any of the three collapses. That is what I mean when I say he doesn't know what he's talking about, regardless of any "4 decades of experience."

I spelled out exactly why I was saying that; feel free to tackle any part of it.

wildbilln864

(13,382 posts)

11. I don't really bother to read all of your lengthy posts anymore Seger...

Reply to William Seger (Reply #9)

Sun Nov 23, 2014, 02:32 PM

Nov 2014

None of it changes the fact that 911 was a false flag operation. Pretend all you want that you can explain away why three highrise buildings completely collapsed in one day for the first time ever but you'll continue to fail. I've grown tired of your sophistry. Office fires do not melt or vaporize steel! The WTC towers were built with massive core columns that tapered as they ascend up the structure. As the collapses progressed downward they should have meet with greater and greater resistance on the way down the undamaged building below but they didn't even slow at all. So continue to piss into the wind all you wish. No one's buying it.