Mechanical Engineers Destroy the Myths

An interesting discussion that many of you may have read, but what's interesting here is the lack of confetti from the F4 into a cement block at high speed.

Good clear photos of the F4 as well as some of the Pentagon.

Here

Originally posted by denythestatusquo
Howard, your avatar there is really cool. Is that a replica of solomon's temple in Jerusalem? Is that the second temple or the proposed new temple?

No, Zam. It's a lego version of an M.C. Escher print.

Originally posted by HowardRoark
Chisel marks? lol lol lol

Yup, and the LOL's don't change it.

Btw, the outer wythe is not brick, but limestone blocks cut to the size of bricks, but 5 inches thick.

Yeah and so? I knew it was limestone toots.

The “straight line” is just where the bricks are cut to fit inside the concrete columns.

Riight. Duuuh It was da noes from the plane. No wait. It was the landing gear. It hit the wall, stopped, spun in a circle and knocked out bricks in perfect circle.

Hey Merc, Where is the evidence of the “reinforced concrete wall” that your “mechanical engineer,” Mike Meyers, went on and on about?

Didn't you see it was in the other thread? Where's your office walls made of drywall and plaster/lath...oh and cant forget the tile.

Originally posted by A_Widows_Son
denythestatusquo:

Did you ever see the movie Twelve Monkeys? That's the first thing that I thought of when I read your statement about the insurance costs!

That is so funny!

You know what movie I thought when seeing your post ahh, can't. But the hint is "special purpose".

Amazing how you took "cleanup cost" and turned it into "insurance costs." It was like the scene with the holes appearing in the car. Killer stuff.

As a businessman (similar to those found in Enron and other fine large corporations) one would see a huge price tag on clean up vs. cheap demolition. How to do a demo? Is there a Bush in the security there? Maybe he can arrange it? Not only no bill for clean up, taxpayers pick up the cleanup, you get 700 million and control the wasteland left over. The brother in the WhiteHouse gets plenty of contracts for friends and stock holders. Nice days work in the industrial military complex.

Not that history would ever show anything as horrifying from a governing body in legal control of a nation.

Originally posted by Merc_the_Perp

Originally posted by HowardRoark
Chisel marks? lol lol lol

Yup, and the LOL's don't change it.

Maybe Lloyd did that while he was waiting for his cab to be moved.

Seriously, are you high or something?

Originally posted by Merc_the_Perp

Originally posted by HowardRoark
The “straight line” is just where the bricks are cut to fit inside the concrete columns.

Riight. Duuuh It was da noes from the plane. No wait. It was the landing gear. It hit the wall, stopped, spun in a circle and knocked out bricks in perfect circle.

?????? WTF are you talking about? You are high. Either that or you are trying to obfuscate the fact that you don't have an answer to that.

EDIT: to be specific, the straight lines are from the expansion joints in the masonry infill. But then again, Merc never lets the facts get in the way of a good theory.

Originally posted by HowardRoark
Hey Merc, Where is the evidence of the “reinforced concrete wall” that your “mechanical engineer,” Mike Meyers, went on and on about?

Originally posted by Merc_the_Perp

Didn't you see it was in the other thread? Where's your office walls made of drywall and plaster/lath...oh and cant forget the tile.

I'm not talking about the interior walls, I'm talking about the claim in the link that you opened this thread with.

To wit:

The final breach of concrete was a nearly perfectly cut circular hole (see below) in a reinforced concrete wall, with no subsequent damage to the rest of the wall. (If we are to believe that somehow this aluminum aircraft did in fact reach this sixth final wall.)

and

It is physically impossible for the wall to have failed in a neat clean cut circle, period. When I first saw this hole, a chill went down my spine because I knew it was not possible to have a reinforced concrete wall fail in this manner, it should have caved in, in some fashion.

Where is this reinforced concrete wall in those pictures?

Huh, "toots?"






[edit on 9-3-2006 by HowardRoark]

Now as for the rather amusing billiard ball analogy.

According to this page about Dr. Wood, her specialty is dental implants and moiré interferometry.

One of her initial claims is this:

Columbia University's Seismology Group recorded seismic events of 10 seconds and 8 seconds in duration, which correspond to the collapses of WTC2 and WTC1, respectively.

Unfortunately, that statement displays a total lack of understanding of seismic waves and how they propagate through the earth.

To begin with the seismic signal received at LDEO was generated when the bulk of the building mass hit the earth. This occurred at the end of the collapse.

If you look at figure 3 in this report you can see that the duration of the signal received at each monitoring station is a function of how far that station is from the source and the intervening geology between the source and the station.

As for the rest of her “billiard Ball” analogy, it is just as flawed.

She bases her entire theory on the assumption that each floor is a separate entity that will not move until impacted by the falling mass from above.

If fact, the floors are part of a structural system. The failures of the individual floors is related to the failure of the structure supporting it as the mass falls rather than with the impact of that mass on the floor slab itself. The falling mass distorted and buckled the structural system ahead of it as it fell. These distortions and buckles overwhelmed the strain energies of the connections with energies an order of magnitude higher then they were able to withstand.

This induces an almost frictionless collapse as the mass fell.

here is a good, simplified, explanation of that process.

Originally posted by HowardRoark

If fact, the floors are part of a structural system. The failures of the individual floors is related to the failure of the structure supporting it as the mass falls rather than with the impact of that mass on the floor slab itself. The falling mass distorted and buckled the structural system ahead of it as it fell.

But Howard, what happened to Euler's Law and the gain in length being the reason the columns collapsed? I mean if the columns are buckling before the floors are seperating from them, how can the columns be losing strength as the verticle length is not being increased? Which is it? Did the floors seperate from the columns first or did the columns buckle first? I'm a little confused.

These distortions and buckles overwhelmed the strain energies of the connections with energies an order of magnitude higher then they were able to withstand.

So, now it's the buckling of the columns that made the connections fail? Dummy me, I thought that the official story line was that the connections failed and then the columns buckled (but yet the connections also at the same time made the columns buckle slightly inward)? Can you explain to me which one happened first? Thanks.

Edit: BTW Howard, you do know that these so called buckling columns (exterior) would reach a connection to other columns only after 3 stories. Which would, by your standards, detach and stop this so called bending and buckling from further continuing down the structure IMO. Maybe not, it's hard to envision what would happen...that's why NIST did a lousy job....because we still can't envision precisely what happened from their report.

[edit on 10-3-2006 by Griff]

Originally posted by ChapaevII

Originally posted by A_Widows_Son
denythestatusquo:

Did you ever see the movie Twelve Monkeys? That's the first thing that I thought of when I read your statement about the insurance costs!

That is so funny!

You know what movie I thought when seeing your post

ahh, can't. But the hint is "special purpose".

Amazing how you took "cleanup cost" and turned it into "insurance costs." It was like the scene with the holes appearing in the car. Killer stuff.

As a businessman (similar to those found in Enron and other fine large corporations) one would see a huge price tag on clean up vs. cheap demolition. How to do a demo? Is there a Bush in the security there? Maybe he can arrange it? Not only no bill for clean up, taxpayers pick up the cleanup, you get 700 million and control the wasteland left over. The brother in the WhiteHouse gets plenty of contracts for friends and stock holders. Nice days work in the industrial military complex.

Not that history would ever show anything as horrifying from a governing body in legal control of a nation.

We are on the same wavelength here dude...

But you don't even need the white house, think about it. Better to seperate politics from reality. All you need to control is this: military, CIA, FBI, NSA etc. Who needs the white house when you control those boys instead.

For our purpose, we may assume that all the impact forces go
into the columns and are distributed among them equally. Unlikely
though such a distribution may be, it is nevertheless the
most optimistic hypothesis to make because the resistance of the
building to the impact is, for such a distribution, the highest. If the
building is found to fail under a uniform distribution of the impact
forces, it would fail under any other distribution.

Brazant/Zhou

the fact that this logic is seriously flawed doesn't bother you, howard?
i think when you base your whole hypothesis on this fallacy, you're bound to produce a compounded fallacy. it would be possible for a global runaway collapse to rip down only one side of the building. the tilting will make a HUGE difference in the reaction of the lower part.
what else? well the perimeter spandrel trees spanned three floors in a staggered 'weave', and the core columns were welded all the way up, forming single 1000 ft high columns. so it is not possible to treat them as a stack of twelve ft. boxes. 'optimistic' might be the wrong word.

and, not far down, here's more...

The energy dissipation, particularly that due to the inelastic
deformation of columns during the initial drop of the upper
part, may be neglected, i.e., the upper part may be assumed to
move through distance h almost in a free fall
is clearly discerned in the photographs of the collapse.

looks like your heroes from BZ have admitted the tower goes instantly into freefall, with no admission that angular deflection would not allow this.

frictionless collapse. what a bad joke.


[edit on 10-3-2006 by billybob]

Griff, the initial collapse started from the floors damaged by the impact and the fire. (i.e. Euler's law)

After that, the rest of the building came down because of the distortions and strains on the structure.

Sorry to cause controversy but the only way a building can be toppled with any degree of predictability is via controlled demolition which is what you would want in a place like NYC. This is a proven industry and a mature one whereby all science has been proven many times over. As you may know NYC is densely populated and has highly expensive real estate. If you take down a building and it falls on annother then you would be subject to a lawsuit.

That is why it was controlled demo, because even by blaming it on some incompetent nobody arabs, they would still have been liable if the buildings toppled onto other property. Lawsuits would have resulted due to any negligence whatsoever by the owners of the WTC even if the cause was terrorism or an act of god.

Originally posted by denythestatusquo
Sorry to cause controversy but the only way a building can be toppled with any degree of predictability is via controlled demolition.

This is your opinion.


What is your educational background? What profesional experience do you have in this that qualifies your opinion?

Chisel marks, people look at that first glance and reject it as chisel marks and quickly move on, well i did but then i went back to it and noticed something quite significant.
If you can get beyond the moustache without wetting your pants, notice above his head the vertical parallel lines are gouged into the limestone, you did say it was limestone?

So when exactly did they make these “chisel marks?” Before hand with a jack hammer? Or how about when everyone was looking at Lloyds taxi not being moved?



Limestone is a natural, sedimentary stone. Can you prove that those are not the fracture patterns typical for this particular type of limestone?

I’m still waiting for someone to point out the reinforced concrete in this wall.

Originally posted by HowardRoark
So when exactly did they make these “chisel marks?” Before hand with a jack hammer? Or how about when everyone was looking at Lloyds taxi not being moved?

Limestone is a natural, sedimentary stone. Can you prove that those are not the fracture patterns typical for this particular type of limestone?

I’m still waiting for someone to point out the reinforced concrete in this wall.

Did i say i see chisel marks, no i never Howard. I see vertical Parallel Lines.

Verticle parallel Lines within the Limestone, Look a few courses directly above the broken line which is pointing out the Straight edge. Sedimentary layers do not form like that in limestone.

The straight edge in that picture is caused by the bricks being layed against a column, what column?

The straight edge on the other side of this hole is much more interesting imo.

How do you get a nice straight line like that when there is a concrete wall standing infront of it.

1) the straight line is caused by vertical expansion joints in the brick.

2) What concrete wall???????

I see a brick wall and behind that (inside the building) a plaster wall on metal lath.

Originally posted by HowardRoark
1) the straight line is caused by vertical expansion joints in the brick.

2) What concrete wall???????

I see a brick wall and behind that (inside the building) a plaster wall on metal lath.

1. Vertical expansion joints are usually situated on the exterior course of the wall, they are also usually just that,vertical all the way up the wall, not vertical then arched at the top like i can see here. They are usually situated in long runs of walls with no breaks/corners, this wall is broken between columns, no need for an expansion joint at all in this situation.

2. Yes it looks like a concrete wall to me, i can see exposed rebar in the hole of the chisel mark picture. You see metal lath and plaster, prove it.


[edit on 13-3-2006 by The Links]

So the metal lath and plaster survived but the brick wall that it covers never, which side was hit first, the inside or the outside?

Do you see that heating pipe in the corner of the hole? The one with the asbestos insulation on it?

It is between the brick wall and the interior plaster finish wall.

Anyone that has ever been involved with interior demolition of a building from that era can confirm that that is a plaster wall on a wire lath (the lath looks almost like cheken wire, yet heavier). The ceiling is the same. You can also see what are known as “black iron” channels that the ceiling lath is attached to. These hang down from the concrete ceiling deck.

I have seen this hundreds of times in the past.

The brick wall broke out in large chucks. The plaster lath wall didn’t really survive intact. Most of the plaster is gone, just the more flexible metal is left.

Are you suggesting that brick is more flexible than plaster?



edit:


look at it from this angle.






[edit on 13-3-2006 by HowardRoark]

[edit on 13-3-2006 by HowardRoark]

The long vertical lines either side of the hole are not uncommon on demolition sights and in this case are brickwork returns - perpendicular walls or pillars.
The fracture patterns, spalling, in the limestone are again not unusual, and are indicative of shear, probably impact shear, and I would say quite pure shear in the sense that it was a massive impact close to the point of impact. Respect to the brickie. who's bond held while the brick didn't.
The vertical parallel lines are the brick coursing, again normal.

What is unusual with this hole is that
The impact seems to have been directed towards the outside perimeter of the hole rather than one central impact. The shear pattern would suggest this.

The debris pattern seems to be quite compact in relation to the impact required. I would expect it to be more scattered with such a large impact.

Most importantly it will be necessary to look at asce-illus-2 if someone can show it to demonstrate my point. ( A plan view showing damaged columns)How did the projectile. which is supposed to have caused this damage, get from the entrance hole to the exit hole without damaging any of the screen of pillars which are in the path? The report shows no damage to these pillars yet the size of the hole and amount of damage would suggest a large and/or fast moving object.

Where is this large or destructive object after impact? If it had only enough energy to cause the damage and no more, it should be in the rubble pile, covered with bits of brick. If it had additional energy it should have struck the next wall or be somewhere on the route between the two, with brick scattered around. This hole does not fit into the aircraft impact scenario and seems to have been a separate though related event.

Gordon