It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Originally posted by pteridine
The core was not able to stand by itself as there was no lateral stability. It does lean before collapse but it doesn't fall over like a tree because it is not rigid enough. If it didn't fall from gravity what did it fall from?
Originally posted by ANOK
On what basis do you claim there was no lateral stability? The thousands of cross braces, and the fact it was sunk into bed rock would allow it to stand. It might not be the safest tower at 110 stories tall, but it wouldn't just simply fail and collapse straight down.
Ever looked at a sky crane lately, same principle, a tower consisting of cross bracing. They manage to stay erect without any other lateral stability, and also lift heavy weights on a cantilever creating instability. BTW the floors of the towers were a cantilever system.
Part of it barely leans before it disappears and is replaced by dust. No solid beam is going to collapse straight down through itself, go ahead and try it. If the column failed at the bottom it would fall like a tree, if the failure was higher up the whole thing would not have disappeared.
Originally posted by pteridine
On the basis that there wasn't any lateral support. Sky cranes are not 1000' feet tall. Look at television antennas for an idea of lateral support.
The tower leans to one side and only then collapses. The dust was on the structure and the structure fell, leaving the dust in the air. No steel turned to dust. The tree analogy is false. Consider that the core was not one piece and that it would fail at many points. Each section would tend to go down more than out.
Originally posted by ANOK
If the bracing failed, at multiple points, the columns would still fall like a tree, a solid object, not fall straight down.
Originally posted by -PLB-
His model that proved progressive collapse assumed that only the mass of the top section was available. That means no mass at all accumulated, or in other words, 100% of the debris ejected.
Why do you think stuff is blown in all directions?
Could it have to do with there being pressure buildup? (hint: yes).
How about this: why don't you prove that more than 50% ejected.
And while you are at it, also explain why exactly this is relevant. What are you trying to prove?
Originally posted by pteridine
The column is not a rigid object. It will not fall like a tree.
HSS, especially rectangular sections, are commonly used in welded steel frames where members experience loading in multiple directions. Square and circular HSS have very efficient shapes for this multiple-axis loading as they have uniform geometric and thus uniform strength characteristics along two or more cross-sectional axes; this makes them good choices for columns. They also have excellent resistance to torsion.
Originally posted by ANOK
On what basis do you claim there was no lateral stability? The thousands of cross braces, and the fact it was sunk into bed rock would allow it to stand.
but it wouldn't just simply fail and collapse straight down.
Ever looked at a sky crane lately, same principle, a tower consisting of cross bracing. They manage to stay erect without any other lateral stability, and also lift heavy weights on a cantilever creating instability.
BTW the floors of the towers were a cantilever system.
Part of it barely leans before it disappears and is replaced by dust.
No solid beam is going to collapse straight down through itself
If the column failed at the bottom it would fall like a tree
if the failure was higher up the whole thing would not have disappeared.
Originally posted by bsbray11
The fact that he is assuming more mass than was actually available is your first and most obvious "clue" from this discussion that his model does not assume conditions most optimistic for the buildings to survive. Adding more imaginary mass that wasn't actually available is contributing to destroying them!
Originally posted by pteridine
reply to post by ANOK
1000 feet of steel is not rigid. If it was why would the complete building sway [est. 20'] in a wind? The core was not laterally supported. 1000 feet of steel is not one piece. It is bolted together. Joints fail.
Look at a steel transmitter tower and tell me why guy wires are needed. If steel is rigid, what are springs made of? Tape measures are steel. Use one as a prybar and tell me how it works for you.
Originally posted by Joey Canoli
The floor beams in the core area had simple connections only. This kind of connection is adequate and all that is needed to support the floor loads.... and serve the purpose of bracing the columns for the purpose of shortening the length of the unsupported column in order to reduce its euler;s buckling length.
For the core columns, on their own, to laterally stable, would require moment connections. But there were none, since all lateral stability was achieved through the composite floors acting as a diaphram through the spandrel plates on other ext columns.
Sure it would.
Without the moment connections, it will lean just a little, which will fracture the welds the joined the individual column sections. So if the lateral velocity at the time of fracture is low, say .1 meter per second, the surviving columns seen in the video will accelerate at gravity. This gives the illusion that it is collapsing straight down, but it isn't. the lateral velocity remains.
And they are designed for this. Also note that they have limits on the wind velocity that they can operate at. Cuz it will result in instability of the crane. there have been many crane disasters because of operators ignoring this safety reg.
Delusional statement.
If a SINGLE 30' column failed due to tipping/joint failure... it would most likely tip like a tree. However, a several hundred foot length, single column MIGHT tip like a tree, depending on its rigidity, length, type of column joining,etc.
Such a blanket statement as yours is useless.
Disappeared?
Originally posted by -PLB-
You don't really know what Bazants model is for and what is proves, you confuse laymen guesstimates with proof, and you are not even making a point in the first place. It is a bit amazing that you take a subject you know little about, start discussing it, and in the end tell you don't even have a point, just a laymen opinion about an irrelevant issue. This illustrates the problem of the truth movement at large, a lack of direction and coherency.
Originally posted by Joey Canoli
The mass included, or 'ejected during the collapse and not able to contribute' in your delusional claim, only affects the spped of the collapse.
Originally posted by slugger9787
reply to post by pteridine
The only thing I can think of that is more rigid that steel, is
the attitude you have about the truth.
Steel is rigid, and flexible.
If a tape measure was four inches thick it would not flex or bend.
Steel for construction is rigid and somewhat flexible.
The metal used for diving boards is flexible.
Originally posted by -PLB-
So, did any of your say last 50 post have any point at all, or was it just about you claiming that I am wrong in an irrelevant issue? Why on earth would you even care about it if is isn't in any way relevant?