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How Does Aluminum Cut Steel?

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posted on Dec, 18 2007 @ 02:14 AM
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Originally posted by six
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?


What? I never said I was 'in the biz'?

Windload was handled by the outer core, that's the reason for the mesh design, so it could move in the wind and still maintain the lateral loads. The main central core 47 box columns handled the majority of the vertical loads. What is so hard to understand here? I believe the core took 80% of the vertical load, maybe 70%, I forget?




posted on Dec, 18 2007 @ 02:44 AM
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Originally posted by OrionStars
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.


Oh for peats sakes. I still don't know where you're getting these tubes in tubes from?

The outer walls were made up of pieces of steel box-beams and I beams welded together in a mesh design then clad in aluminum...









How it takes the lateral loads...



No tubes in tubes, no concrete, and they weren't the main load bearing structure, the central core was. I'm not going to argue this nonsense anymore...



posted on Dec, 18 2007 @ 02:51 AM
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reply to post by ANOK
 


Nice pics


I would like to have him explain how the outer shell was supposed to handle not only the lateral loads but the gravity loads of the entire structure? Unless it was made of unobtanium I just don't see how it could be done.

I checked with my father who is an actual civil engineer and had him look at the thread and he agrees with just about everybody here that the building was constructed as advertised.



posted on Dec, 18 2007 @ 03:02 AM
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Originally posted by FredT

I checked with my father who is an actual civil engineer and had him look at the thread and he agrees with just about everybody here that the building was constructed as advertised.


Hey Freds Dad


I too am a card-carrying Civil Engineer, with qualifications in Structural Mechanics and Design of Structural Elements.



posted on Dec, 18 2007 @ 03:13 AM
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reply to post by OrionStars
 


Orion,

You are welcome and thanks for the links. I believe these are the "Plaza Level" stairs and are not typical as to what would have been found throughout the rest of the structure. They would be too heavy and not as flexible as how I described earlier. (Let me add a disclaimer here. I have not read everything you have posted in this thread, so I'm not familiar with the materials list you are referring to. Like I said, long day, I'm tired, and just can't seem to sleep at the moment.)

Unfortunately, just from a quick search, finding the real blueprints for either of the towers from the initial construction isn't going to be an easy find. I do see a number of results about alleged leaked copies in searching google. I did take a peek at "Loose Change" site and the sample he had posted. Maybe after downloading the whole file the copy will be clearer and it will have the "detail" of each area showing how the architect intended each area be laid out. (The detail shows where he wants each penetration to occur, what gauge framing, etc. that he wanted to use)

I did find this pic of the cleanup and it shows what I was describing:




Whoever posted this image was nice enough to add the labels. The 16" gypsum wallboard planks are what we call "Shaft Wall", but what I want to point out are the stairs here. Standard steel construction welded to each floor pan. This would have been lighter and more flexible than an all concrete stairway. I wish I could find a "before" picture or detail to see how the stairway looked all the way up, but I can be pretty sure it was all how I described before.



posted on Dec, 18 2007 @ 03:18 AM
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Originally posted by ANOK
Oh for peats sakes. I still don't know where you're getting these tubes in tubes from?


if he saw the same documentary i saw then i think i know where he gets it, i think he just misunderstood it.

one of the (or a random one i dunno) architects was talking about how they were going to build the buildings with a "tube in tube" design for a stronger yet lighter building.


MY understanding was that he was referring to the core structure as ONE of the tubes and then the perimeter as a SECOND tube and they were just going to hang the floors between them.

NO WHERE did i see them talking about taking a column and putting it inside another column and after filling it with concrete using 1000's of these to build the outter walls. im so at a loss about where that idea came from.

BUT, if my understanding of the documentary was right, then anok, nefermore, et al are totally right about the construction and this idea of concrete filled "tubes" is just a case of misunderstanding a random or erroneous quote on a random website.

just my $.02

PS and is it just me or did the world slow down a bit, i agreed with ANOK on something.............JK man, nothing but respect.



posted on Dec, 18 2007 @ 11:30 AM
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Originally posted by ANOK
Oh for peats sakes. I still don't know where you're getting these tubes in tubes from?

The outer walls were made up of pieces of steel box-beams and I beams welded together in a mesh design then clad in aluminum...


Box columns are single beams. The exterior primary load bearing frames were not single beams. There are enough pictures on the Internet to validate that. I have already provided links to photos, of the exterior wall frames to this forum.

Box columns sit on a lower support and then are positioned to support what lies above the lower support. That is not the way the exterior load bearing walls were placed on the building.

wrhstore.com...



[edit on 18-12-2007 by OrionStars]



posted on Dec, 18 2007 @ 12:32 PM
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You said...


Originally posted by OrionStars
Box columns are single beams. The exterior primary load bearing frames were not single beams.


The site you quoted said



The buildings' signature architectural design feature was the vertical fenestration, the predominant element of which was a series of closely spaced built-up box columns.


and then goes on to say



The resulting configuration of closely spaced columns and deep spandrels created a perforated steel bearing-wall frame system that extended continuously around the building perimeter.


So are you arguing against the site you, yourself have quoted, or did I miss something?

I also note that it makes no mention of concrete, and that the section shown through the column has no concrete detail shown on it. I assume you have conceded that point?



posted on Dec, 18 2007 @ 12:43 PM
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Here's a good photo of the "box" columns tied together with spandrel plates. No concrete. Just steel, eventually clad in a thin aluminum facade.



2PacSade-



posted on Dec, 18 2007 @ 12:43 PM
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The core columns disappeared at the same time that the rest of the Tower turned into dust from the top down. The core was so robust that it is IMPOSSIBLE for those 47 massive steel supports to have been crushed beneath any amount of weight, they would have buckled, not simply been turned to dust!! The core loses ALL its ability to stand and hold weight as the top turns to dust and explodes outwards. What is so hard about seeing that this can ONLY be caused by massive energy? Gravity? That would a laughable if it did not make one choke at the idiocy of it..Fire? Please. Local and cool fires giving back smoke and little flame can turn a core like that into dust?

All it takes is a look at the Towers going to dust to show anyone, no matter the education, that in no way, shape or form could the Towers have ' collapsed ' as we saw due to the energy given by fire and gravity. No way. Cannot be. It staggers the sound mind to imagine people seeing something so brazenly contrived and yet so many say: Just the way it happens', without any thought as to the impossibility of it all. The Towers got shredded for God's sake!! Turned to dust!! Right in front of us and here we are, years later, with some people still imagining that the official story might be true..it boggles the mind to think that people could be so thick.

Remember the film of the ' Spoire'? Turning the core to dust is a feat that no one has explained yet with fire and gravity. But who needs science when we have the film!! It shows the towers falling and a plane hit so thats all we need to know, right? Unreal..just unreal..what has happened to critical thinking and challenging nonsense from the govt.?



posted on Dec, 18 2007 @ 12:48 PM
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Originally posted by OrionStars
Box columns sit on a lower support and then are positioned to support what lies above the lower support. That is not the way the exterior load bearing walls were placed on the building.


This sounds like you are describing "lally" columns, which are indeed steel filled with concrete.



2PacSade-



posted on Dec, 18 2007 @ 01:54 PM
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reply to post by sheetrockerr
 


According to the photo at this link, there was a 17' thick cast concrete core wall at the above ground base of one of the towers. The arrow to the rebar indicates reinforced concrete walls not floors (only 4" in depth):

911review.org...

You will have to scroll down to see the photo. I posted this to substantiate that there was more concrete internally inside WTC buildings than the floors. As for the walls in other stairwells, I did read the walls were several layers thick of sheetrock (purpose of depth - fire retardant - because of lack of concrete being used as the primary fire retardant in the stairwell walls).

However, I also read, in another article, the steps (not certain about the deck between stair sections) were steel frames clad in a thin (whatever "thin" means for specs) layer of concrete. Now I cannot locate the article on the stair material I did find yesterday. I believe it was in an engineering, possibly architect, journal. That article was discussing the materials used on the walls and steps but not the decks.

I did find this photo of stairwell steps which may or may not be concrete coated.

www.graduatingengineer.com...

There is also a picture of an esculator which may or may not be a concrete frame holding the escalator. It is difficult to determine from the photo.

Vincent Dunn, ex-NYFD - has estimated the ratio of concrete to steel in the WTC buildings was 40:60. He stated most highrises are 60:40 respectively. At 40%, all that concrete dust on collapse did not come from just flooring. It could not have.



posted on Dec, 18 2007 @ 02:04 PM
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Originally posted by 2PacSade

This sounds like you are describing "lally" columns, which are indeed steel filled with concrete.


Box column example:

911research.wtc7.net...

"Columns

The core columns were steel box-columns that were continuous for their entire height, going from their bedrock anchors in the sub-basements to near the towers' tops, where they transitioned to H-beams. Apparently the box columns, more than 1000 feet long, were built as the towers rose by welding together sections several stories tall. The sections were fabricated by mills in Japan that were uniquely equipped to produce the large pieces. 2 "



posted on Dec, 18 2007 @ 02:14 PM
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Structural design of WTC towers.

en.wikipedia.org...

Structural design
The World Trade Center included many structural engineering innovations in skyscraper design and construction. The towers were designed as framed tube structures. There was a frame of closely-spaced columns tied together by deep spandrel beams along the exterior perimeter. The interior had 47 columns, all concentrated in the core. Engineer Felix Samuely used a similar concept in his "Mullion wall" buildings in the early 1950s as did Eero Saarinen in his US Embassy, London (1955-60); but these projects were low to medium rise and may not have been influences.

The perimeter columns supported virtually all lateral loads, such as wind loads, and shared the gravity loads with the core columns.[6] All columns were founded on bedrock, which unlike Midtown Manhattan, where the bedrock is shallow, is at 65 feet (20m) below the surface. Above the seventh floor there were 59 perimeter columns along each face of the building. The perimeter columns had a square cross section, 14 inches on a side (36 cm), and were constructed of welded steel plate.[6] The thickness of the plates and grade of steel were varied over the height of the tower, ranging from 36 ksi to 100 ksi, with the steel strength and plate thickness decreasing with height.[6] The perimeter structure was constructed with extensive use of prefabricated modular pieces, which consisted of three columns, three stories tall, connected together by spandrel plates. The spandrel plates were welded to the columns at the fabrication shop. The modular pieces were typically 52 inches (1.3 m) deep, and extended for two full floors and half of two more floors.[6]


Looking up, 1992Adjacent modules were bolted together, with the splices occurring at mid-span of the columns and spandrels. The spandrel plates were located at each floor, and served to transmit shear flow between columns, thus allowing them to work together in resisting lateral loads. The joints between modules were staggered vertically, so the column splices between adjacent modules were not at the same floor.[6]

The building's core housed the elevator and utility shafts, restrooms, three stairwells, and other support spaces. The core in 1 WTC was oriented with the long axis east to west, while that of 2 WTC was oriented north to south. The core of each tower was a rectangular area 87 by 135 feet (27 by 41 m) and contained 47 steel columns running from the bedrock to the top of the tower.[6] The columns tapered with height, and consisted of welded box sections at lower floors and rolled wide-flange sections at upper floors. All of the elevators and stairwells were located in the core.

The large, column-free space between the perimeter and core was bridged by prefabricated floor trusses. The floors supported their own weight, as well as live loads, provided lateral stability to the exterior walls, and distributed wind loads among the exterior walls. The floors consisted of 4 inch (10 cm) thick lightweight concrete slabs laid on a fluted steel deck. A grid of lightweight bridging trusses and main trusses supported the floors. The trusses had a span of 60 feet (18.2 m) in the long-span areas and 35 feet (11.0 m) in the short span area.[6] The trusses connected to the perimeter at alternate columns, and were therefore on 6 foot 8 inch (2.03 m) centers. The top chords of the trusses were bolted to seats welded to the spandrels on the exterior side and a channel welded to the core columns on the interior side. The floors were connected to the perimeter spandel plates with vicsoelastic dampers, which helped reduce the amount of sway felt by building occupants. The trusses supported a 4-inch-thick (10 cm) lightweight concrete floor slab, with shear connections for composite action.[6]

Hat trusses (or "outrigger truss") located from the 107th floor to the top of the buildings were designed to support a tall communications antenna on top of each building,[6] though only 1 WTC (north tower) actually had an antenna. The truss system consisted of six trusses along the long axis of core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower.


Design innovations

A typical floor layout and elevator arrangement of the WTC towersTo solve the problem of wind sway or vibration in the construction of the towers, chief engineer Leslie Robertson took a then unusual approach — instead of bracing the buildings corner-to-corner or using internal walls, the towers were essentially hollow steel tubes surrounding a central core and perimeter columns sharing the loads. The 208 feet (63.4 m) wide facade was, in effect, a prefabricated steel lattice, with columns on 39 inch (100 cm) centers acting as wind bracing to resist all overturning forces; the central core took the majority of the gravity loads of the building.



posted on Dec, 18 2007 @ 02:25 PM
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It looks like pages 2 through 4 mentions the use of concrete filled steel tubes (CFST) in the WTC outer wall (with pictures)... not sure if this is what Orion is talking about... or even if it is relevant, but here you go...

Link:www.tamu.edu...









[edit on 18-12-2007 by b309302]

[edit on 18-12-2007 by b309302]



posted on Dec, 18 2007 @ 02:38 PM
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Originally posted by eyewitness86

The core columns disappeared at the same time that the rest of the Tower turned into dust from the top down. The core was so robust that it is IMPOSSIBLE for those 47 massive steel supports to have been crushed beneath any amount of weight, they would have buckled, not simply been turned to dust!! The core loses ALL its ability to stand and hold weight as the top turns to dust and explodes outwards. What is so hard about seeing that this can ONLY be caused by massive energy? Gravity? That would a laughable if it did not make one choke at the idiocy of it..Fire? Please. Local and cool fires giving back smoke and little flame can turn a core like that into dust?


That, and the fact steel does not turn to dust, except when it starts making rust "dust".

I agree. The fires were never hot enough to begin to compromise any core columns or any other steel. Directly around the core columns, was nothing flammable to allow a fire to burn. Kerosene, without a flammable catalyst, will remain cooler (from all that energy to burn its own carbon base first) and will burn itself out very quickly. If there was fuel on the steel, once the fuel was burned, the fire goes out, but the metal can still contain heat. However, to compromise, the metal has to be heated at some significant depth until it raises to a temperature that can significantly compromise the steel.

Something can be compromised but that means little in telling anyone how significantly something was compromised, i.e. Did the temperature of the steel reach a degree where significant amount of steel was compromised from degree of temperature and lost rigid support?

Separating each floor steel floor truss and crossing steel supports was 4" of fire retardant reinforced concrete.

The steel used in the WTC towers is going to start buckling in only 56 minutes or an hour and 42 minutes, when, in 1975, a blowtorch type fire, burning for 3 hours or more, did not even begin to buckle the core supports, or any other steel, on 6 floors of the North Tower's 11th floor section? It was concentrated on the 11th floor where it started. There were no signs of compromise as the hottest point - the 11th floor after 3 hours or more with a much hotter fire.



posted on Dec, 18 2007 @ 02:48 PM
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Originally posted by b309302
It looks like pages 2 through 4 mentions the use of concrete filled steel tubes (CFST) in the WTC outer wall (with pictures)... not sure if this is what Orion is talking about... or even if it is relevant, but here you go...

Link:www.tamu.edu...


Yes, thank you for presenting that. I also located that one and was going to present it myself. As I recall, I was referring to the facade. That is a lightweight concrete, which I doubt would ever be used for load bearing support, but would be for reinforcement in hollow tubes. It would be used for reinforcement against buckling when flexing too much, as in the case of 100 mph winds NYC does get.

[edit on 18-12-2007 by OrionStars]



posted on Dec, 18 2007 @ 03:25 PM
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Regarding the poster who questioned about why then the F4 in the video does not break apart the concrete barrier, please read the following enclosed pdf concerning the technical review of impacting an F4 vs a large airliner into the concrete. You will notice the density of the reinforced concrete is also considerably higher then that of the kinetic force of the impacting aircraft. Test data used in the review of their simulation came directly from the F4 impact test.


The B747 is almost 15 times as heavy as the F4

When a concrete slab is impacted by a high speed projectile with a blunt nose a region near the rear surface of the slab is damaged because of hydrostatic tension waves…

In our simulation the ejection of concrete is not observed.

A slight dent is formed at around the impact area.


www.engineering-eye.com...

However should you decide to ram the same plane into some spread out (non reinforced) plain carbon steel beams with some gypsum board various aluminum conduit, copper wiring 6" of concrete and some glass I am sure you will find your impromptu "shredder" being equally demolished by the impacting aircraft. The WTC did not have a solid sheet steel face, nor was it 3 or 4 feet thick solid steel face. Had that been the case the impacting aircraft more then likely would have caused considerably less damage to the WTC towers.





[edit on 18-12-2007 by robertfenix]



posted on Dec, 18 2007 @ 04:12 PM
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Originally posted by ULTIMA1
Structural design of WTC towers.

The building's core housed the elevator and utility shafts, restrooms, three stairwells, and other support spaces. The core in 1 WTC was oriented with the long axis east to west, while that of 2 WTC was oriented north to south. The core of each tower was a rectangular area 87 by 135 feet (27 by 41 m) and contained 47 steel columns running from the bedrock to the top of the tower.[6] The columns tapered with height, and consisted of welded box sections at lower floors and rolled wide-flange sections at upper floors. All of the elevators and stairwells were located in the core.


Thank you for posting that. It makes a stronger case for me from another post, regarding the length of a 767 at 159' and some inches.

I had previously stated that part of the back half of any airplane should have been seen extended outside the WTC buildings. At 159', and only 67' before core meeting from one direction, and only 43' before meeting the core from another direction, that leaves a great deal of plane that should have been extended outside buildings on both towers. The actual diminsions work better for my argument.

The way we have been shown it happened is the twin towers literally inhaled two 159' commercial airplanes. That means the planes would have had to slice through enough of the center core supports, to pull in 92' foot of plane on one side, or 116' on the other. That further means, 159' of airplane would definitely have compromised strategic supporting core columns, while causing buckling in the rest, when the side that was impacted began to lean toward the impart hole. Considering all the other structural damage the "official" report has told us happened.

No one is going to convince me that some plane was all that was holding up strategic center core supports in either twin tower, until the plane buckled immediately prior to collapse. Leaning toward the side of impact will cause the top to topple to the side of impact, not drop straight down, causing a square building to come straight down into its own footprint.

If planes did not get passed core columns, that means that a great deal of the back half of the plane would have entended outside the exterior walls. 159' commercial airliners just don't crush into neat little compactor shaped units under high impact. They may break apart, but not crush to lengths of 67' or 43' feet so they cannot be seen at all through those holes, even with all that dense black smoke pouring out.

A 767 is 78% the length of each tower's length or width (204 x 204), with a 135'x 87' core in the middle.

That impact and inhaled look was the first scene that told me something funny (not funny ha-ha) was going on in Washington, DC. Then when the official version came out, I thought I had suddenly entered the Twilight Zone of up is down and down is up.



posted on Dec, 18 2007 @ 04:20 PM
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Originally posted by OrionStars
Thank you for posting that. It makes a stronger case for me from another post, regarding the length of a 767 at 159' and some inches.


Yes, but you have to remember the plane that hit the South tower went in at an angle through the side of the building, so it did not cause much if any damage to the core.




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