Why the Towers Fell - An Exclusive Investigation into the Collapse of the World Trade Center

Rating:
Summary: Excellent Documentary
Review: This is a very nice documentary it explains in details why the two WTC actually fell. It is full of Engineering facts, however, it has some interviews with some of the September 11 survivors who were very close to the major events. Also an interview with the WTC architect who in my view lost two loved ones. I would recommend this documentary for every one, it has allot of footage of the September 11 attack which makes it a collectable item for those who want to capture all the moments they can.

Rating:
Summary: Structural Engineering On Why The Towers Fell
Review: This Nova film is well done. It is the first time that I have learned engineering-wise why the towers fell. From this information engineers in the future can change their designs to include additional safeguards in the designs of tall buildings. The design of the World Trade Center did contain weak points that could have been avoided and should be avoided in any future building construction.

Rating:
Summary: Extraordinary Coverage
Review: Wouldn't you call the catastrophic collapse of two modern skyscrapers within hours of one another a failure of structural engineering?

A bomber hit the Empire State Building during World War II and the building didn't fall down.

On 9/12/2001 I called a close friend who is a structural engineer. He said something really scary to me: "The World Trade Center towers exceeded spec; they stayed up for more than an hour each."

"You mean to tell me that it's OK for a skyscraper to collapse during a fire so long as it stands up for an hour?"

"Pretty much, yes."

Until I saw this coverage, these words really haunted me. Nova's outstanding work here in "forensic engineering" is, to me, more exciting than the CSI fictions we see. They explain clearly how the design was motivated by confidence in existing safety parameters and maximization of interior rentable space.

Perhaps most compelling is the extensive interview footage with the chief structural engineer who, in an extraordinary display of courage and integrity, answers tough questions about his work and its consequences. It's unforgettable.

Back to the first question: the Empire State Building "shrugged off" the WWII bomber because of "structural redundancy." It is made of a cage of more or less same sized columns and girders. If one part of the structure fails, the rest of the structure takes up the strain.

The WTC had the same properties, but with a very different concept. You have to see this video to understand it in full...

By the way, throughout all American cities, there are WTC-type structures. So you have an hour...