Correct me if I'm wrong but I think someone a while back said those cars were moved there temp in the cleanup.
Originally posted by pdoherty76
...Where are the floor pans that held the concrete?...
For most of the last 2 years since the last extended maximum power transmission on 9/11 2001, HAARP has only been on the air for several hours each month for regular monthly transmitter maintenance.
Still, Robertson, whose firm is responsible for three of the six tallest buildings in the world, feels a sense of pride that the massive towers, supported by a steel-tube exoskeleton and a reinforced concrete core, held up as well as they did—managing to stand for over an hour despite direct hits from two massive commercial jetliners.
The building‘s design was standard in the 1960s when construction began. At the heart of the structure was a steel and concrete core, housing lift shafts and stairwells. Steel beams radiate outwards and connect with steel uprights, forming the building’s outer wall. All the steel was covered in concrete to guarantee firefighters a minimum period of one or two hours in which they could operate – although aviation fuel would have driven the fire to higher-than-normal temperatures. The floors were also concrete. Newer skyscrapers are constructed using cheaper methods. This building was magnificent, say experts, in the face of utterly unpredictable disaster.
For some of the fire officers, that confidence might have been based on a misconception about how the towers were built: The FDNY chief of safety says in his oral history that he thought the towers were made of block construction, with a solid concrete core
Each of the WTC towers had a double-strength structure consisting of a concrete core supported by a steel structure around the outside.
Groundbreaking for construction of the World Trade Center took place on August 5, 1966 Tower One, standing 1368 feet high, was completed in 1970, and Tower Two, at 1362 feet high, was completed in 1972. The structural design for the World Trade Center Towers was done by Skilling, Helle, Christiansen and Robertson. It was designed as a tube building that included a perimeter moment-resisting frame consisting of steel columns spaced on 39-inch centers. The load carrying system was designed so that the steel facade would resist lateral and gravity forces and the interior concrete core would carry only gravity loads.
Dr. Domel received a Ph.D. from the University of Illinois at Chicago in 1988 and a Law Degree from Loyola University in 1992. He is a licensed Structural Engineer and Attorney at Law in the .State of Illinois and a Professional Engineer in twelve states, including the State of New York. Dr. Domel is authorized by the Department of Labor (OSHA) as a 10 and 30 hour construction safety trainer.