Reply #148: Allot of Heresay and Supposition There [View All]

[Show_Me _The_Truth]

World Trade Center tower construction
In terms of structural system the twin towers departed completely from other high-rise buildings. Conventional skyscrapers since the 19th century have been built with a skeleton of interior supporting columns that supports the structure. Exterior walls of glass steel or synthetic material do not carry any load. The Twin towers are radically different in structural design as the exterior wall is used as the load-bearing wall. (A load bearing wall supports the weight of the floors.) The only interior columns are located in the core area, which contains the elevators. The outer wall carries the building vertical loads and provides the entire resistance to wind. The wall consists of closely spaced vertical columns (21 columns 10 feet apart) tied together by horizontal spandrel beams that girdle the tower at every floor. On the inside of the structure the floor sections consist of trusses spanning from the core to the outer wall.

Concrete removal
Since the end of WWII builders designed most of the concrete from the modern high-rise constriction. First concrete they eliminated was the stone exterior wall. They replace them with the “curtain walls of glass, sheet steel, or plastics. This curtain wall acted as a lightweight skin to enclose the structure from the outside elements. Next the 8-inch thick concrete floors went. They were replaced with a combination of 2 or 3 inches of concrete on top of thin corrugated steel sheets. Next the masonry enclosure for stairs and elevators were replaced with several layers of sheet rock. Then the masonry smoke proof tower was eliminated in the 1968 building code. It contained too much concrete weight and took up valuable floor space. Then the solid steel beam was replace by the steel truss. And finally the concrete and brick encasement of steel columns girders and floor supports was eliminated. A lightweight spray-on coating of asbestos or mineral fiber was sprayed over the steel. This coating provided fireproofing. After asbestos was discovered hazardous vermiculite or volcanic rock ash substance was used as a spray-on coating for steel. Outside of the foundation walls and a thin 2 or 3 inches of floors surface, concrete has almost been eliminated from high-rise office building construction. If you look at the WTC rubble at ground zero you see very little concrete and lots of twisted steel.

http://vincentdunn.com/wtc.html

The towers were designed and built in the mid-1960s through the early 1970s. They represented a new approach to skyscrapers in that they were to be very lightweight and involved modular construction methods in order to accelerate the schedule and to reduce the costs.

To a structural engineer, a skyscraper is modeled as a large cantilever vertical column. Each tower was 64 m square, standing 411 m above street level and 21 m below grade. This produces a height-to-width ratio of 6.8. The total weight of the structure was roughly 500,000 t, but wind load, rather than the gravity load, dominated the design. The building is a huge sail that must resist a 225 km/h hurricane. It was designed to resist a wind load of 2 kPa—a total of lateral load of 5,000 t.

In order to make each tower capable of withstanding this wind load, the architects selected a lightweight “perimeter tube” design consisting of 244 exterior columns of 36 cm square steel box section on 100 cm centers (see Figure 3). This permitted windows more than one-half meter wide. Inside this outer tube there was a 27 m × 40 m core, which was designed to support the weight of the tower. It also housed the elevators, the stairwells, and the mechanical risers and utilities. Web joists 80 cm tall connected the core to the perimeter at each story. Concrete slabs were poured over these joists to form the floors. In essence, the building is an egg-crate construction that is about 95 percent air, explaining why the rubble after the collapse was only a few stories high.

http://www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html

Where do you see that the core was steel reinforced concrete? What is your source for this? I'm not talking about someone who talkd to someone who might remember but won't give a statement, I am talking about building plans. Oh wait, they must be secret.

I would have given your explosives planting theory a little more credence if you would have said they used the ongoing (since the mid-90's) program to update the fire retardant system on the core to get access without arousing suspicion.

Where is your information coming from on the placement of C4? Above you stated that the drawings you made were your own and only estimations, but now you jump to pretty specific statements about parafin caps, etc, etc

Forced evacuations? For how long, minutes, hours, days? How long do you think it would take to place at least 14 tons of C4?

Again, if the plans for the core were changed at the last minute, again, wouldn't one enigneer at least come forward and say so? By the way, how do you change the plans for 2 x 100 story buildings at the last minute without comment, not to mention the public and code enforcement scrutiny that would have been going on at the time of construction. What does last minute mean?

30 hours to set 14 tons of C4 (or much more as you stated)? All I have to say is, HAH! Tell that to skilled demolitions experts that take weeks with an unoccupied building to set their charges.

I'm not asking about detonators, I'm asking about the actual explosives.

"A large part of the men working on the towers have since died?" Come on, there were over 10,000 workers that worked on the WTC in 1968. Assuming (like you do allot of) that they were in their mid-20's to early 40's, that would place ALLOT of them in their 60's right now. So how can you say that a large part have since died? There must have been allot of bad luck in that crew. Where is your source?

I see allot of assumptions and unverified statements from you and your "sources" but no proof. I don't have to prove that this didn't happen, you have to prove that it did.