Scientists simulate jet colliding with World Trade Center

[TheLegacy]

http://edition.cnn.com/2007/WORLD/am...ion/index.html

NEW YORK (CNN) -- A computer simulation of the September 11, 2001, attack on the World Trade Center, posted on the Web site YouTube by Purdue University researchers, shows how hijacked planes crashed through the twin towers, stripping fireproofing materials from the steel columns and eventually leading to their collapse.

The 3-D animation, part of a Purdue study that took two and a half years to complete, will hopefully help engineers design safer buildings, researchers said.

"When the developers of the World Trade Center first designed the complex, they did take into account of an accidental plane crash," said Christoph Hoffman, one of the study's lead researchers. "The only thing they didn't anticipate is the fire. If the crash impacts the water line, then a fire can burn for a long time."

The simulation was posted on YouTube June 1, and received more than 2,000 hits in the first hour, Hoffman said. As of Wednesday, it had garnered more than 120,000 views. (Watch video simulation on YouTube of a jet hitting the World Trade Center)

Researchers decided to post the simulation on the popular Web site because of the animation file's size, which could not be adequately supported by their servers, he said.

The Perdue study offers slightly varying estimates on the internal damage to the towers than the findings of an earlier study, done in 2005 by a government panel. In their report, the National Institute of Standards and Technology (NIST) issued recommendations to make skyscrapers stronger and make "buildings, occupants and emergency responders safer in future emergencies."

NIST listed 30 recommendations for buildings over 20 stories, including enhanced fireproofing such as coating or painting steel beams with the material -- a more secure application than the spray-on fireproofing inside the twin towers that was dislodged when Boeing 767 airliners crashed into them.

NIST has previously concluded that the dislodging of the fireproofing was a key factor contributing to the collapse of the towers.

NIST also recommended new standards for fire-testing building components, such as steel and reinforced concrete, and installing redundant fire response equipment, such as sprinklers, hoses, and alarms.