Twin Towers' Designers Anticipated Jet Impacts Like September 11th's

[wakeme2008]

I saw this Thanksgiving Day on Bartcop. Sorry if Dup.


http://911research.wtc7.net/wtc/analysis/design.html



According to Hyman Brown, a University of Colorado civil engineering professor and the World Trade Center's construction manager, 1 and 2 World Trade Center were designed to survive an impact and resulting fires from a collision by the largest commercial aircraft at the time, a Boeing 707-340. 1 Contrary to widely promoted misconceptions, the 767-200s used on 9-11 were only slightly larger than 707s.

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Like All Skyscrapers, the Twin Towers Were Over-Engineered

One aspect of engineering that is not widely understood is that structures are over-engineered as a matter of standard practice. Steel structures like bridges and buildings are typically designed to withstand five times anticipated static loads and 3 times anticipated dynamic loads. The anticipated loads are the largest ones expected during the life of the structure, like the worst hurricane or earthquake occurring while the floors are packed with standing-room-only crowds. Given that September 11th was not a windy day, and that there were not throngs of people in the upper floors, the critical load ratio was probably well over 10, meaning that more than nine-tenths of the columns at the same level would have to fail before the weight of the top could have overcome support capacity of the remaining columns.

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Frank Demartini's Statement

Frank A. Demartini, on-site construction manager for the World Trade Center, spoke of the resilience of the towers in an interview recorded on January 25, 2001.
The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jetliners because this structure is like the mosquito netting on your screen door -- this intense grid -- and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.

Demartini, who had an office on the 88th floor of the North Tower, has been missing since the 9/11/01 attack.

..more at link....