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How Does Aluminum Cut Steel?

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posted on Dec, 17 2007 @ 01:40 AM
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Originally posted by ANOK
All I can say Oquote]Originally posted by ANOK

All I can say Orion is do more research you have it all backwards...You keep insisting the central core took the lateral loads, this is not the case.

Why do you think the outer walls were a mesh design? So it could move laterally absorbing the loads.

Look at pictures of the building being built and you can quit clearly see NO concrete.


Unless one can see through steel or look down the end of a hollow core, I do not know how someone would know what sits inside hollowed out steel. Do you? The building is still under construction, and lower core area cannot be readily seen. There is no way to know exactly what was done inside the core where the stairwells and elevator shafts were eventually located.



Yes I meant the floor slabs were concrete, sitting in steel pans, that was the only concrete.


Do you mean forms? As I stated, you are entitled to believe whatever you wish, regarding the amount and placement of concrete. I previously stated to you or another poster, regarding the same subject, I was agreeing to disagree.


Try to find any other reference for your claim, and then look for references for mine and see which one comes up more than once...


I am inclined to accept the words of the architect and those who actually saw the building materials before they were used. If you are not, that is up to you.


The tube in a tube nonsense came from a very simplified, and misleading, graphic of the buildings design here...


It is not misleading and aptly describes the design. If people think tubes only come in round shapes, then it may be confusing. It is the same principle as putting a curtain rod together or adding an entension to a vacuum cleaner hose. One end slips into the other end to a certain length. In the case of WTC, the tubes just happened to have 4 sides where one tube dropped into another but only up to a certain length - tube-in-tube.



I don't see any tubes, do you?


I could not make a comparison. Your first link is missing. I saw the tubes in the second picture all along the outside walls. They might be easier to see with a magnifying glass.




posted on Dec, 17 2007 @ 01:52 AM
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Originally posted by FredT
reply to post by OrionStars
 


The article you linked failed to mention ANY concrete in the exterior of the structure in regards to the load bearing exterior. In fact based on the comments of the designers of the building, he is in error. The external wall of the WTC was designed for lateral wind loads the core for the cravity load of the building.


The one I linked described it inside the tubing did not fail to mention it. The architect is in error? Because that site referenced the architect and people who saw the materials before they went into construction.


He also makes a case for the aluminium aircraft pretty much slicing through the building all the way to the core.


Since I linked in at least 2 websites, which article would that be? Could you cite the words you believe "....also makes a case for the aluminium aircraft pretty much slicing through the building all the way to the core.", plus, reference the site from which you cite those words?


Im not sure what you want us to see in the picture. Im not seeing much steel encased in concrete


That is good. Because it was concrete encased in steel. Not the other way around.



posted on Dec, 17 2007 @ 02:03 AM
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Originally posted by FredT
reply to post by OrionStars
 


Yes, and they all interrelate, however, without mass and Velocity the other factors are null eh?


One cannot have mass and velocity relevant to anything without resistance and momentum. In your post, there seemed to be such emphasis on mass and velocity without mention of momentum and resistance or gravity. It is rather misleading to leave out necessary factors. Unless, in a vacuum with no resistance, and that still leaves necessary weight, mass and momentum consideration.



posted on Dec, 17 2007 @ 04:40 AM
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Originally posted by OrionStars
Originally posted by jfj123
Originally posted by OrionStars
Wood and steel do not have the same dimensional bearing capacity so it's not really a fair question. Just my humble opinion.

Then you completely missed the point of my highly relevant analogy, with concentration on load bearing capability. No matter what type of building is built, it has to have solid primary and secondary load bearing capability. That was my point.

Many building foundations and walls are built with hollow concrete blocks which are load bearing.


Would you use hollow core wood load bearers or not? Particularly, in consideration most wood rough framing is made out of softer pine and not some other harder wood. If not, why not? Is so, why so?

1. Hollowing out a 2" x 4" lengthwise is not practical.
2. Could a hollow weight bearing support post be created? Of course.
3. Ever been in a retail store where you see large metal posts that go from the floor to the ceiling, at various points throughout the store? Well those are hollow, load bearing support posts.
4. There are quite a few different hollow core structural supports available. Just google "building hollow load bearing supports" or something similar and you'll get quite a few hits.



posted on Dec, 17 2007 @ 06:55 AM
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Originally posted by jfj123

Many building foundations and walls are built with hollow concrete blocks which are load bearing.


Which may be the designed steel reinforced and look like the photo on the website. Not exactly the concept I had of hollow:

www.hindu.com...



1. Hollowing out a 2" x 4" lengthwise is not practical.


Or strong enough for load bearing either, particularly primary load bearing.


2. Could a hollow weight bearing support post be created? Of course.


Anything can be manufactured, but can the design be successfully used as primary load bearers for extended periods of time, particularly during high stress conditions?



3. Ever been in a retail store where you see large metal posts that go from the floor to the ceiling, at various points throughout the store? Well those are hollow, load bearing support posts.


Yes, I have seen both metal and reinforced concrete primary load bearing columns in commercial buildings. However, if there is internal support inside the metal, i.e. at least one crossbar from end to end, to keep them from flexing too far and breaking away during high stress, they are not considered hollow. Are they actually hollow, or do they have internal support of some type running through them? How thick are the walls of the posts?

I understand the principle behind having a steel post that is say 30" in diameter and hollow, plus, the lower cost. But under high stress conditions knowing steel flexes, I am not certain a hollow,internally non-reinforced post, depending on depth of the walls, would withstand high stress. Then there is always a strong possibility of corrosion on the inside that would never be noticed, until it reached the outside.

If you are referring to retail outlets, such as grocery stores, the most primary load being carried is normally the roof. Those are not the type of primary load bearing columns nor types of commercial buildings I had in mind. I realize you had no way of knowing that, which is why I am not fond of the use of generalities.


4. There are quite a few different hollow core structural supports available. Just google "building hollow load bearing supports" or something similar and you'll get quite a few hits.


I already did, and found nothing, for what my concept of hollow, for use in commercial buildings, particularly those for buildings the size of the WTC twin towers. Internally containing hollow reinforced areas and being hollow is not the same thing.



posted on Dec, 17 2007 @ 07:10 AM
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OK. Am sick of this.

This is THE defining problem of arguments about 9/11. Ignorance. We're here to deny it. So, lets have a little challenge, shall we?

As far as I - and a number of other posters are concerned - there was no concrete in the outer walls of the WTC. No evidence has been provided of such, at all.

None of the websites I have visited and looked at give details of concrete in the outer walls.

So - the challenge is this. Orion - back it up properly or lose it.

Lets have some properly documented proof - and by that I mean in the manner thats been provided to you already by multiple posters to prove that there was NO concrete used there.

Lets see multiple sites, photos and references that prove what you claim. Not just the same thing repeated over and over and you repeating what you think you know. Set it out clearly, in one post with all the links in that we can follow.

If you can't provide the documented evidence of concrete clearly being used in the outer walls of the WTC then I suggest you concede the point, and we can move on.

We've all done the hard work to try and prove this to you so far, and all you've done is obtusely refused to believe it, so now its your turn. Forget all the pointless references to wood etc. Make your case.

I would suggest that the rest of us sit back and wait to see the presentation.



posted on Dec, 17 2007 @ 07:39 AM
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posted on Dec, 17 2007 @ 08:05 AM
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Originally posted by OrionStars
What isn't your perogative is harassment of people doing more than taking the easy way out as you chose to do.


First off, no one is harassing anyone.

Let me set this out. Zaphod, Anok, Aim, JfJ and Fred T - all of whom are recent contributors to this deabte have all pointed out - with links, on more than one occasion, that what you are saying is wrong.

The easy way out - as you want to put it - Orion, is not doing what I asked above.

So prove it to us.

Just do it.

It should be simple if what you say is true.



posted on Dec, 17 2007 @ 09:52 AM
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Originally posted by OrionStars
Unless one can see through steel or look down the end of a hollow core, I do not know how someone would know what sits inside hollowed out steel. There is no way to know exactly what was done inside the core where the stairwells and elevator shafts were eventually located.


The ‘hollowed out’ steel you’re talking about are called box-beams/columns, not really ‘hollowed out’ as such and that is not what they meant with tube-in-tube design. I-beams were used for cross-bracing, pretty basic stuff.
And they don't put concrete inside box columns, why would they? What purposed would doing that serve? If concrete was used it would have been around the outside of the steel columns and very visible in construction pictures.
Again do some research the design was the first one to use NO masonry! Why are you so stubbornly holding on to that one article you found?

I can take a wild guess what was put into the shafts, elevators, sealed with gypsum/sheet rock.



Do you mean forms? …I previously stated to you or another poster, regarding the same subject, I was agreeing to disagree.


What? More semantics? Jeez are we taking the piss or what? What do you mean by forms now? You said 'did I mean floor slabs' and I yes I did, move on…



I am inclined to accept the words of the architect and those who actually saw the building materials before they were used. If you are not, that is up to you.


Again you are stubbornly hanging on to an obviously incorrect statement. If there was concrete in the core and the outer mesh show me. I will say you can't do it, and outside of your one little article there is no other mention of it only the contrary...


It is not misleading and aptly describes the design. If people think tubes only come in round shapes, then it may be confusing. It is the same principle as putting a curtain rod together or adding an entension to a vacuum cleaner hose. One end slips into the other end to a certain length. In the case of WTC, the tubes just happened to have 4 sides where one tube dropped into another but only up to a certain length - tube-in-tube.


All I can say is that is nonsense. Go do some research...


…I saw the tubes in the second picture all along the outside walls


They are NOT TUBES they are box columns, and they are the outside walls covered in aluminum cladding...lol, you sound like you're describing a different building. Why do you insist on calling them tubes?

Also where is the rebar in the construction pictures? Why no pictures if this concrete core? I guess they must have built the whole building and then put the concrete in secretly while no one was looking…


Look, halfway up and no concrete yet?...



No concrete in sight…





The outside columns, looking out from the inside, where is the concrete? Steel and glass baby…




[edit on 17/12/2007 by ANOK]


six

posted on Dec, 17 2007 @ 02:46 PM
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reply to post by ANOK
 

I have question for you and since your in the business. Would it be the outside "shell" or the inside core that would be responsible for handling the windload? Or would the load be split between the two?



posted on Dec, 17 2007 @ 02:47 PM
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Originally posted by OrionStars
Originally posted by jfj123

Many building foundations and walls are built with hollow concrete blocks which are load bearing.

Which may be the designed steel reinforced and look like the photo on the website. Not exactly the concept I had of hollow:

www.hindu.com...


Well nonetheless, they are hollow blocks. Not the ones I was referring to but those also work as an example. Also notice the title of the article says they're hollow blocks???


2. Could a hollow weight bearing support post be created? Of course.


Anything can be manufactured, but can the design be successfully used as primary load bearers for extended periods of time, particularly during high stress conditions?
Yes, there are many types of hollow core support structures being used in building today.


3. Ever been in a retail store where you see large metal posts that go from the floor to the ceiling, at various points throughout the store? Well those are hollow, load bearing support posts.


Yes, I have seen both metal and reinforced concrete primary load bearing columns in commercial buildings. However, if there is internal support inside the metal, i.e. at least one crossbar from end to end, to keep them from flexing too far and breaking away during high stress, they are not considered hollow. Are they actually hollow, or do they have internal support of some type running through them? How thick are the walls of the posts?
The hollow support posts which I am referring, have no internal support structure. If you cut a cross section, it would look like a ring with air in the middle. It doesn't matter how thick they are as hollow means hollow regardless of wall thickness.


I understand the principle behind having a steel post that is say 30" in diameter and hollow, plus, the lower cost. But under high stress conditions knowing steel flexes, I am not certain a hollow,internally non-reinforced post, depending on depth of the walls, would withstand high stress. Then there is always a strong possibility of corrosion on the inside that would never be noticed, until it reached the outside.

I can tell you that as long as the posts are situated correctly to accommodate weight, they work just fine. As a matter of fact, I have been in a few 100+ year old buildings with metal support posts from original install and they're working just fine.


4. There are quite a few different hollow core structural supports available. Just google "building hollow load bearing supports" or something similar and you'll get quite a few hits.


I already did, and found nothing, for what my concept of hollow, for use in commercial buildings, particularly those for buildings the size of the WTC twin towers. Internally containing hollow reinforced areas and being hollow is not the same thing.
well I found 65,100 hits from google. Maybe what would help is a very detailed description regarding your concept. Your wording may be whats causing the confusion. I'm not trying to be sarcastic, I just want to understand exactly what your concept is.



posted on Dec, 17 2007 @ 08:34 PM
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Originally posted by ANOK

And they don't put concrete inside box columns, why would they? What purposed would doing that serve? If concrete was used it would have been around the outside of the steel columns and very visible in construction pictures.


I never said or implied they did. The subject was the innovative primary load bearing exterior wall framing, not traditional steel beams,

Did you forget the stairs - 110 stories from ground level up? What do you think those were made of? Drywall? Hiow much protection is drywall in elevator shafts and stairwells, in the case of fire or any exceptional load stress? Have you bothered to think through what you write, based on even normal standards of commercial buildings construction? Because it does not appear you have.



posted on Dec, 17 2007 @ 10:36 PM
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Originally posted by jfj123

Well nonetheless, they are hollow blocks. Not the ones I was referring to but those also work as an example. Also notice the title of the article says they're hollow blocks???


It was one of the links for hollow block when I searched using the words hollow block. Those are not the only design of construction hollow block, which is not actually hollow, but have internal steel reinforced divided areas which are hollow. That is why using the vague word hollow implies there is nothing separating the inside walls and the air inside. As if having lack of compressed air is any insurance of holding against high stress conditions, such as buckling.


Yes, there are many types of hollow core support structures being used in building today.


Again, it depends on what people call hollow. As you pointed out above, it appears as if I am not the only one questioning how the word hollow is used when something is not actually completely hollow.

[quoteThe hollow support posts which I am referring, have no internal support structure. If you cut a cross section, it would look like a ring with air in the middle. It doesn't matter how thick they are as hollow means hollow regardless of wall thickness.

Yes, it does make a difference in wall depth. Would it make a difference between a 1/2'" vs a 7" circumference wall depth when it came to prevention of buckling or crushing under high stress conditions? I bet it would.

[quoteI can tell you that as long as the posts are situated correctly to accommodate weight, they work just fine. As a matter of fact, I have been in a few 100+ year old buildings with metal support posts from original install and they're working just fine.

Have any unusual events happen that test those hollow columns under abnormal stress? If not, there is no actual way of knowing how they will respond under abnormal stress conditions. I am only going by what you are saying since I have not seen them or know the material specs on them.

I suppose what you contend will have to be demonstrated under variable conditions, because saying it and making it so is not necessarily the same. The base principle can be easily tested at home. If one takes two pieces of same material spec metal tubing - one being hollow and the other solid (different designs but same material specs), and horizontally places each in a vice, which will begin to buckle first when pressure starts to and increasingly builds?


well I found 65,100 hits from google. Maybe what would help is a very detailed description regarding your concept. Your wording may be whats causing the confusion. I'm not trying to be sarcastic, I just want to understand exactly what your concept is.


I did not say I did not find thousands of sites using words you suggested and some of my own. I said they did not meet my concept of hollow, as applied to my concept of non-reinforced construction material, in such high rise buildings such a the WTC, particularly primary load bearing supports.

Something can be called "hollow", but that does not necessarily mean it is not internally reinforced. Unless someone sees it in manufacturing stages, or can look inside a finished product, or can read the material specs, no one will ever know if something is actually hollow and not internally reinforced somehow (internal crossbars or concrete tubes covered in steel and then slipped into another final denser layer of exterior steel).



posted on Dec, 17 2007 @ 10:49 PM
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Originally posted by ANOK

They are NOT TUBES they are box columns, and they are the outside walls covered in aluminum cladding...lol, you sound like you're describing a different building. Why do you insist on calling them tubes?



You asked me if I saw tubes. I did. Now you say "THEY" are "box columns". Exactly, to what are your referring? I was referring to the tube-in-a-tube exterior primary load bearers. Those were definitely not on record as "box columns". Simply because the tubes are not round, does not make the exterior wall supports any less an innovative tube design as stated for over 40 years on record.

You can change the terminology on record all you wish. However, all it does is damage your credibility when you do it.



posted on Dec, 17 2007 @ 10:58 PM
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Originally posted by OrionStars

Did you forget the stairs - 110 stories from ground level up? What do you think those were made of? Drywall? Hiow much protection is drywall in elevator shafts and stairwells, in the case of fire or any exceptional load stress? Have you bothered to think through what you write, based on even normal standards of commercial buildings construction? Because it does not appear you have.


(Pardon me if I ramble a bit. Long day and very tired)
OK, most construction does exactly this. The stairwell is lined with nothing but sheetrock and steel stud framing. The sheetrock is usually double layered and fire taped. Fiberglass in the wall for sound proofing. Commercial construction uses 5/8" thick 4'x12' sheets of rock. All joints on the outer layer must be taped for fire proofing and other penetrations must be caulked or taped. Depending on what the customer wants, it's usually finish taped so that it can be painted, but I've had plenty that don't care if the wall is painted, so just tape and mud on the joints with some sanding to smooth it out. The steel studs are usually 20 gauge, which are easily cut with a pair of tin snips. If it weren't for the double layer of rock, we would actually go to 22 gauge (pretty much paper thin) to save on cost and weight. Most stairways are not lined with cement. Costs too much, is too heavy, and too time consuming to form and pour. The staircase is usually made of steel and welded to the upper and lower floor pans for support.

Elevator shafts use a green papered rock called "shaft wall". It's around an inch thick, 2' wide by 8-10' long. It is stood up length wise to reduce cutting so it can be hung quickly. Again, all joints (which are mostly horizontal because the steel stud frame is an H channel) must be fire taped. Again, a lot of elevator shafts are not made of cement for the same reason I stated about the stairwell. Most elevators used in a high rise have their own steel frame (smaller and lighter than what would be used for a core column) to support and guide the elevator. With shaft wall in place plus standard rock for the office walls, only a little fiberglass insulation is needed for sound proofing.

As for fire taping joints, there's nothing special about it. A coat of mud, then tape (which is just paper), then another coat of mud to seal the tape. Usually the last layer of mud is about 6" (3" on each side of the joint). Other penetrations like conduit or water pipe must either be fire taped or sealed with fire proof caulking. The whole idea is to prevent air being drawn or expelled through the joints. I haven't witnessed it myself, but talking with the firemen around here, they say a flame coming through a joint is just as hot as a cutting torch and just as effective.

As for your average sheetrock wall (single layer), it is rated for one hour in a fire. Double rock on both sides is rated for 2 hours. The problem with "fire rating" sheetrock walls is that they are usually compromised after initial construction. Someone punches a hole (usually above the ceiling grid) and never seals it.

Shaft wall, is rated at one hour per layer of rock.



posted on Dec, 17 2007 @ 11:17 PM
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The destruction of all firestair access to the upper floors (above the impact zone) of at least one tower gives us a good idea of how much damage was actually done to the central core structure by fast moving aluminium and other alloys.



posted on Dec, 17 2007 @ 11:40 PM
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reply to post by sheetrockerr
 


I appreciate the imput. However, as I have stated before, the WTC high rises were not built like any other high rises. They were built redundantly for the highest safety standards and abnormal stess variables.

A surving WTC concrete staircase, which visually confirms what I posted, based on the website I linked referencing architect description of material specs in the WTC:

www.usatoday.com...

"WTC staircase leads endangered sites list

WASHINGTON (AP) — Anyplace else, the scarred concrete steps would be an eyesore. At ground zero on Sept. 11, 2001, they were a last chance for escape. Now they stand as the last surviving above-ground piece of the World Trade Center."

"The "Survivors Staircase" was named one of the nation's most endangered historic places Wednesday, along with whole swaths of New Orleans and Mississippi damaged by Hurricane Katrina."

www.msnbc.msn.com...




[edit on 18-12-2007 by OrionStars]



posted on Dec, 17 2007 @ 11:52 PM
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That may be misleading in the context of this discussion
From the NY Times:


After hundreds of workers made a terrifying floor-by-floor descent from their offices in the sky on 9/11, as the twin towers shuddered and rained ruin, they found a gangway to safety from the elevated plaza down the Vesey Street stairs.


That suggests not the fire stairs but the stairs from the elevated plaza down to street level.



posted on Dec, 18 2007 @ 12:51 AM
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Constructed "to the highest safety standards" and "to withstand an intentional jetliner impact" are two completely different things, and two completely different forces.

Concrete is VERY vulnerable to things such as an Earthquake and fire (because concrete can sometimes contain air bubbles, it can pop and explode when exposed to fire... even though measures are taken to avoid this, it's still a factor/risk). Steel is much more flexible than concrete, and far stronger for the weight (additionally, it possesses tensile strength and has some slightly elastic properties - making it more resistant to torsion). So, a building built with more steel than concrete is a good thing. Concrete provides some rather impressive vertical support and anchoring properties, but, otherwise, it is a bad thing in larger structures that are subject to many lateral forces (wind).

Also, the staircases and elevators were all contained in the central core (which did contain some concrete). This was done for convenience and partially for functionality. The elevators were also located in the core... I forget the exact numbers, but the elevator structure was that so that there was only one elevator that ran the entire height of the structure (IIRC). It was segmented so that the highest you could go was 20 floors at a time, then you would have to get on another elevator. The reason for this, again, is convenience and functionality. Conventional high-rise elevator setups would have made the first several floors a sea of elevators... and no usable floor space.

So, the core seemed like a nice spot to put elevators (it will do the least amount of flexing, and is already surrounded by a very sturdy set of support columns), stair wells, etc. So, everyone is happy.



posted on Dec, 18 2007 @ 01:27 AM
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Originally posted by OrionStars

A surving WTC concrete staircase, which visually confirms what I posted, based on the website I linked referencing architect description of material specs in the WTC:



From the article you quoted in your post. Bold emphasis is mine.



She had already walked down 65 flights of stairs when she got to the World Trade Center plaza. Debris from Tower 2, which had just collapsed, filled the plaza, leaving the open-air staircase as the only way out.


This was an external staircase, and not part of the main tower structure, and has such has nothing to do with the main tower construction.

Its a non sequiter.

[edit on 18/1207/07 by neformore]



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