esdad71, I'm not trying to talk in circles, I'm trying to uphold Occam's Razor - looks like I'll have to repeat myself: Focus on WTC7's collapse, from the time it sustained damage to the time it fell, exclude everything else for now. Right now, we want to figure out how to explain the observed phenomenon (rapid symmetrical collapse), nothing else. How could the building fail in this manner?

-implosion

This is straightforward insofar as this mode of collapse is well known from controlled demolitions - we know those happen, so we don't have to rely on possibly far-fetched assumptions. It's perfectly plausible to assume that a pre-planned detonation sequence precipitated the collapse in the manner witnessed.

-non-uniform fires

This, in contrast, seems like a stretch: We would have to assume that somehow, non-uniform fires could fatally weaken the entire loadbearing structure in an instant in order to bring about the perfectly symmetrical and complete collapse in order to back this theory - which, as the laws of probability suggest, is extremely unlikely, and thus far-fetched. Just like assuming a monkey with a typewriter would coincidentally reproduce shakespeare's hamlet.

So there, it's not exactly rocket science. It's imperative to keep in mind that the implications (esp. politically) of those theories are irrelevant for their evaluation on the grounds of Occam's Razor. To employ a contemporary "scenario": If a giant explosion occurs somewhere in a midwestern city and geiger-counters go wild around the crater, how would you explain it?

-nuke

Appears likely, doesn't it - however, the implications are that someone must've somehow delivered it, so would you want people to meticulously provide the details as to who, how, when - or would you accept this theory as is?

-A cow ate too much uranium-contaminated grass, acquired critical mass in its bowels and detonated

Now that's another theory, but it's assuming what never happened before - just like implosion-like collapses from random fires. Would you rather believe that?

Yes. I caught the History channel special. It was pretty informative, and the gas lines and strogae do provide some insight as to some issues that may have led to the collapse, but then again heat has no effect on steel. or so I have read on ATS.

Can one of you guys give a brief synopsis of the History Channels show? I missed it and am interested in hearing about it. Thanks.

As for WTC 7, I thing a couple of points should be established.

1. The building was significantly damaged by the collapse of WTC 1. Unfortunately, there aren’t any pictures where the damage was not obscured by smoke. None the less, there is credible testimony from the firemen on the scene that a considerable portion of the south face had been damaged.
   
   
2. The fire. I don’t know what Lumos means by ”non-uniform, but again, there is considerable evidence that there were significant fires in this building as well. No, the whole building wasn’t engulfed, but several of the lower floors were fully involved. In addition, the sprinkler systems were not functioning, and the fires were burning for 7 hours before the collapse. Based on this, I think it is reasonable to assume that the structure was adversely affected by the fire.
   
   
3. Structure: The building had an unusual structural design to accommodate the large electrical substation in the basement. This involved the use of large transfer trusses. In addition, the structure of the building was modified with the addition of a penthouse and the reconfiguration of the steel on one of the top floors. Thus, the building can not be considered to be a “typical” steel framed building.
   
   
   
   Finally, there are two other considerations, poor design or poor workmanship. It is impossible to determine what role, if any, these factors had in the collapse, yet we can not simply dismiss them out of hand.
   
   As for the collapse itself:
   
   
   1. The speed of the collapse is not indicative of anything. In actuality, the NIST report documents several precursors to the global collapse that indicate the structural failure had started several seconds prior to the complete failure of the entire structure. At that point where the whole structure starts to come down, the argument that there should be some sort of inherent resistance to collapse is not supported by engineering.
      
      
   2. As to the symmetry of the collapse, again, I don’t think that that is indicative of anything. Like the speed argument, it is not supported by engineering dynamics.
      
      All it really does indicate is that the initial failure occurred somewhere in the center of the building and the adjacent structural elements were unable to handle the additional load transferred to them (either because of poor design, or because they too were close to failure and under the same conditions that caused the initial failure.
      
      
      
      That is the real debate about WTC 7. Was the failure caused by poor design, or was it simply a case of the structure being unable to handle the cumulative physical damage with the stresses and damaged caused by the fire.
      
      
      (I’m not even going to address the “nuke” issue as it is totally absurd.)
      

Originally posted by bsbray11

Maybe not structural engineering, because structural engineers don't design buildings to fall. This is more in the field of demolition engineering or even basic physics.

Actually the term you are looking for is “Forensic engineering.” This is the process by which engineers study structural failure and learn how to avoid it.

Yes, structural engineers don’t design buildings to fall, but they know why they do, otherwise how could they know how to avoid it.

Where all of the engineers that think the buildings are were deliberately demolished?

Originally posted by HowardRoark

Where all of the engineers that think the buildings are were deliberately demolished?

I thought the towers WERE deliberately demolished? Whether it was by some terrorists or our own government is a different story. Now, I think your question means if the towers were demolished by planes and fire alone or with planes, fire and explosives. I'll let others decide for themselves. I'm still up in the air on the subject.

I was thinking last night. Lets think about it this way. Say the towers are still standing. I somehow magically make a floor (say the 94th floor) just disappear. What I mean is take out all supporting columns at that floor in an instance (heck, even make it all the supporting columns from the top of the 93rd floor to the bottom of the 95th floor to make it exactly like a floor collapsing from fires). Would people expect that the whole building would still fall in on itself the way they did?

If so, why don't demolishions experts just use this method of implossion? It would definately save on time and expenses wouldn't it? Just blow out the top 10 percent of the building to have it collapse by gravity in on itself. I know what people are going to say.."well, they use that method so the building doesn't fall on other surrounding buildings, etc." But, these are the same people who will say that there is no other way that the towers or other buildings will fall except on themselves (Eager). Why do they (the demolitions engineers) take all that time planning, planting and initiating a controlled demolition the way they do?

[edit on 27-1-2006 by Griff]

Originally posted by HowardRoark
They also tend to use either masonry or concrete in the structure, something that the towers did not.

The only thing masonry or concrete is going to do differently is fireproofing. In my scenario, there are no fires, just the destruction of support columns. Look into the strength of steel and strength of concrete if you don't believe me. In compression, steel and concrete are about the same. In tension however, steel is much stronger than concrete...hence why concrete is usually reinforced with steel.

So, the construction materials (steel and concrete) are negligable in my scenario. Actually, concrete would have less strength.

Originally posted by HowardRoark
To begin with, a building the size of the WTC towers would never be demolished using explosives, as it would be impossible to guarantee that the debris wouldn’t hit other buildings.

Why not? You yourself like to quote Eager when he says that there is no other way a building that size could fall. So why wouldn't they use explosives in a building that size if there is no other way for the building to fall but within it's own footprint?

Remember that the towers were designed to be as light as they possibly could. That is not the same as older buildings wich were built without the aid of computers and modern strucutral analysis.

Originally posted by HowardRoark
To begin with, a building the size of the WTC towers would never be demolished using explosives, as it would be impossible to guarantee that the debris wouldn’t hit other buildings.

By a company, under the law.

When you're trying to justify war, and you're killing so many anyway, who cares?

The other buildings were damaged.


Now, when a building falls on its own, you could expect some severe lopsiding from the portion of the building providing least resistance to the falling material (portion with most damage; most missing columns). That would've caused some damage. Pretty damned *lucky* that the buildings fell straight down symmetrically without ever lopsiding.

Originally posted by HowardRoark
Remember that the towers were designed to be as light as they possibly could. That is not the same as older buildings wich were built without the aid of computers and modern strucutral analysis.

Aside from being totally irrelevant and straying from Griff's point, you seem to be trying to suggest that the buildings were weak. Far from fact. Skyscrapers have to be extremely strong, and be able to hold much more than their own weight under law. It's illegal for huge skyscrapers to be flimsy. NYC Building Code maintains that skyscrapers have to be able to support something like 250% of their own weight or more for a length of time without any visible damage appearing. No house of cards.