NewsMine — 9-11 — wtc-collapse — Viewing Item

Fire wasnt hot enough to bring down towers says study { April 6 2005 } Original Source Link: (May no longer be active)    http://www.baltimoresun.com/news/nationworld/bal-te.wtc06apr06,1,2039876.story?coll=bal-nationworld-headlines http://www.baltimoresun.com/news/nationworld/bal-te.wtc06apr06,1,2039876.story?coll=bal-nationworld-headlines Damage to fireproofing took down Trade Center Towers could have stood if shields held, report says By Stevenson Swanson Chicago Tribune April 6, 2005 NEW YORK - Neither the impact of two passenger jets nor the raging fires they ignited were enough to bring down the World Trade Center towers by themselves, according to a comprehensive study of the towers' collapse released yesterday. But when the planes hit the twin towers on Sept. 11, 2001, they dislodged the fireproofing protecting the steel columns and trusses that held the buildings together. That proved to be the key factor, according to the National Institute of Standards and Technology. Stripped of protection, the steel sagged after prolonged exposure to temperatures of at least 1,000 degrees, triggering the towers' pancaking collapse that killed 2,749 people. But lead investigator Shyam Sunder said the failure of the fireproofing was not as a result of improper installation or lax maintenance. "You would not expect fireproofing to be installed to withstand the impact of an airplane," Sunder said, speaking at a news conference at a Times Square hotel. "We are not suggesting here that people should design buildings to withstand airplanes." Based on mathematical modeling that pushed the boundaries of computer science, the agency's conclusion is the most authoritative statement likely to emerge about the sequence of events on Sept. 11, 2001. The institute's wide-ranging investigation is examining not only the engineering issues behind the collapse but also the evacuation of the towers, the response of police, firefighters and other emergency personnel, and many technical issues. The study is intended to find out whether current building codes, construction practices and emergency procedures need to be revised to take account of the threat of terrorism. At yesterday's conference, the agency released three reports on which it has completed work, including a study of how occupants evacuated the building and how communications hampered firefighters. To re-create the impact of the two fuel-laden Boeing 767 passenger jets, investigators created extremely detailed mathematical models of the planes and the towers. In both cases, the planes broke apart into thousands of fragments within one second of striking the towers, Sunder said. The impact was so powerful that the south tower swayed for four minutes. The jet fuel burned up in a few minutes, but it ignited the contents of the floors, such as papers and furniture. Even so, the towers likely would have remained standing if the impact had not also dislodged the sprayed-on fireproofing material that covered the towers' steel columns and floor trusses, the study found. Since the attacks, several theories have been put forward about the sequence of events that caused the towers to collapse. Questions arose about the reliability of the towers' design, an innovative arrangement of exterior columns linked by floor trusses to an inner core of columns. Some architects and engineers speculated that the trusses separated from the outer columns in the fire and led to the collapse. Sunder said the institute's investigation concluded that, apart from the impact areas, the trusses mainly stayed in place. But subject to high heat and stripped of fireproofing, they sagged and pulled the fire-weakened outer columns inward. The Chicago Tribune is a Tribune Publishing newspaper. Copyright © 2005, The Baltimore Sun

051205explosives [wmv] 270404northtower [jpg] 270404southtower [jpg] 2750 degree fire melts bridge steel beams { April 30 2007 } 7 wtc collapse { November 29 2001 } Ailing wtc rescue workers sue 1b insurance fund { July 18 2007 } Body searched halted for gold search at wtc { March 9 2007 } Bush insider said collapse was controlled demolishion Bush says ksm planted explosives in a building Comparing twin towers { October 23 2002 } Debate over wtc fires draws experts { November 15 2004 } Dislodged fireproofing key to wtc collapse Engineering report released in trade center collapse Engineers built wtc to withstand boeing jet { February 27 1993 } Fire engineers challenge fed theory { May 27 2002 } Fire wasnt hot enough to bring down towers says study { April 6 2005 } Firefighters call giuliani 911 perfomance a disgrace Fireproofing dismissed as wtc collapse cause { October 19 2004 } First struck seconds to fall { February 24 2002 } Giuliani accused on streets of allowing wtc deaths { May 29 2007 } Giulliani caused firefighter deaths on 911 { January 22 2008 } Giulliani promoted those who ran before towers fell Graphic look { October 29 2002 } Human remains search could move off site Madrid building fire ap [jpg] Madrid skyscraper burns 24 hours without collapse Madrid windsor tower burns but no collapse { February 14 2005 } Medical examiner says lung death from wtc debris { May 24 2007 } Nist response to wtc controlled demolition accusations Nist still cant figure out why wtc7 fell { June 2007 } NY firefighters face questions on collapse { November 14 2003 } Over 750 bone fragments found on deutsche bank building { October 26 2006 } Planes hit tower weakest spot { September 12 2001 } Report on trade center collapse emphasize fireproofing { April 5 2005 } Search for human remains at wtc grows { October 27 2006 } Silverstein pull wtc building 7 [mp3] Stephen jones attacked on msnbc Study faults bolts Study suggests design flaws didnt doom towers { October 20 2004 } Topple [jpg] Towers fell almost free fall { April 30 2002 } Why world trade center collapsed Woman_in_blackhole [jpg] Woman_wtc [jpg] Wtc collapse evidence Wtc collapse inquiry rules out design flaw Wtc collapse secret { September 30 2002 } Wtc huge pile driver { September 13 2001 } Wtc officials recover more human remains { October 24 2006 } Wtc pull building 6 [mp3] Wtc structure built to withstand jet crash { February 27 1993 } Files Listed: 51

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