September 11, 2001 The ZOT is Coming out

11-12-05 | tinfoil hat troll

[supercat]

The wtc main support was provided by the central shaft, which in essence was a giant sized pillar (Like a tree trunk, but a little more complicated than that). Each slab also had "walls" which ran all the way to the exterior (in a cross shape from the center like you say. The pillars gave support and stability in between those for the floor above. I think we are on the same page essentually. There is a blueprint around somewhere which shows how the towers were built.

Most of the weight of the floors was supported by the walls. The floor trusses themselves had essentially zero cantilever strength (meaning that if one end was unsupported, it would fall even if the other end was supported), and also meaning that unless the trusses were loaded non-uniformly (and I see no reason to believe that they were especially so) the ends of each truss would bear equal load. There were IIRC three "kinds" of truss. There were trusses that went from the central core to the exterior walls and supported only the weight of the floor in the immediate vicinity. Those trusses would put half their weight on the core and half on the exterior walls. There were trusses that went from the core to the wall and supported other trusses (basically four of these per floor). These would again put half their load on the core and half on the walls. Finally, there were trusses that went from the second group of trusses to the walls. These would put half their load on the wall, and half on the transfer trusses which in turn put half the load on the wall and half on the core. While the core did support a very large portion of the weight (including itself) the exterior walls bore more than half of the floor weight.

[Alice au Wonderland]

Where do they come up with this tripe? It's not worth the red ink from my venomous quill to respond to this lackwit.

[Darksheare]

"The truth is gaining momentum"

You've been hanging out with TLB haven't you?

[Christopher Lincoln]

But in that case, why would it be necessary to hijack the planes?

[Calpernia]

I don't know. The explosions were always the question marks that were in my head. But I'm satisfied with the explanation that was in post 111.

[Thunder90]

[Thunder90]

Troll PING!

[ladyinred]

You've been hanging out with TLB haven't you?

Is that his latest Bush smear?

[Darksheare]

Dunno, but he likes to say "The TRUTH blah blah blah" often..

[Watery Tart]

The truth is gaining momentum

You're RIGHT!!

---

And this PROVES IT!

[concretebob]

BINGO...we have a winner in the "How Come those Buidings Fell" category.
I was also a welder. Then became a commercial concrete worker.
Now I'm a building inpsector..oh wait...a "damn" building inspector..have to keep those titles straight..
I inspect, among other things, the spray-applied fireproofing for commercial buildings..it's a nasty looking, gray colored, cementitious, (sea-men-ti-shus) material, which looks like elephant snot with hair..
but it will protect the structural steel framing of a building for 3 hours, at 2200 degrees Farenheit...I doubt it will protect a building from a commercial airliner loaded with fuel, though.
What amazed me at the time, was that Congress had to convene a special hearing to find out what I, or backhoe, or any construction worker who has built them, could have explained in 5 minutes, without visual aids.

[backhoe]

[concretebob]

Almost forgot the most important factor...
the concrete floor slabs..
assuming the floors were lightweight concrete..(a contradiction in terms for some, I know) the per cubic foot weight of LW concrete ranges between 114 pcf to 118 pcf..(as opposed to "hardrock" concrete, which is 147 pcf to 152 pcf..)
Thats JUST the concrete..I don't remember the exact square footage of the floors, but I'm sure someone knows..(assume 20,000 sq feet per floor,)
at 4 inches thick, every yard of concrete theoretically yields 81 square feet..a yard of concrete is 27 cubic feet. 116 pcf x 27 = 3,132lbs..so for every 81 square feet, you have 3,000 lbs..theoretically, of course..
now just to make the math easy, lets say 100 square feet per yard..200 units of floor space, 20,000 divided by 100=200..thats 600,000 lbs per floor or 300 tons...PER FLOOR..just the concrete..theoretically, of course.

I had also heard or read somewhere, that these building had the structural support members on the outside of the building..a new type, (in 1963) of construction technique..self-supporting floor slabs, tied to the structural elements..

[concretebob]

If you are not familiar with the interior mechanical elements..i.e., HVAC, water lines, gas lines, hydronic piping, (heating water), of a commercial building, you can't know what will happen during an intense fire.
Lines already pressurized, will explode when heated.
Methane gas from sanitary waste-lines will explode.

[Calpernia]

I didn't realize that either. That does make sense too.

Thank you very much for that insight.

[concretebob]

BTW if you'd like a small idea as to how commercial buildings are constructed, see my website..you can link from my profile page.
Its only a 3 story hospital with a 5 story bed-tower, but the principle is the same..central tower...steel framing tied to columns..massive columns..on massive footings..
this hospital was also designed and built under the new 2000 International Building Code, which incorporates the California Office of Public Safety's requirements for seismic resistance, and FEMA's guidelines for essential facilities..
(yes, the same FEMA which was in NO,LA..)
they do other stuff besides respond to natural disaters..
I have approximately 14 FEMA publications in e-book format loaded on my laptop..all of which address seismic resistance, structural steel welding, and design criteria for moment resisting steel frame buildings,
in addition to the 2000 and 2003 International Building Codes in e-book format.
If you are the curious type, you can go to ecodes.biz and download the FEMA publlcations for free.
I highly reccommend the FEMA publication "State of the Art Report on Welding of Moment Resisting Frames"..heady stuff..
just throwing this out there for the edification of my FReeper FRiends..
I live this stuff (thats not a typo)..I also love this stuff, sometimes, but I do have some horror stories..
I will say this..St Francis Medical Center is the best designed, most well-built medical facility on the East Coast, probably in the country, and it's where I would want to be if the New Madrid fault line ever acts up again.