*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~* { Sila lawat Laman Hizbi-Net - http://www.hizbi.net } { Hantarkan mesej anda ke: [EMAIL PROTECTED] } { Iklan barangan? Hantarkan ke [EMAIL PROTECTED] } *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~* PAS : KE ARAH PEMERINTAHAN ISLAM YANG ADIL ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Fire, not impact, caused collapse of towers: experts Rob Lever 1:34pm, Thu: WASHINGTON (AFP) - The collapse of the World Trade Center towers resulted from the intense fire that melted structural support, not the impact of the hijacked jetliners that crashed into each of the skyscrapers, experts said yesterday. Engineers and architects said the huge amounts of jet fuel caused an inferno with temperatures as high as 1,000 degrees Celsius (2,000 Fahrenheit), melting the supporting steel and eventually causing the 110 story towers to implode. "The fire brought it down ultimately," Henry Petroski, a civil engineering professor at Duke University, told AFP. "Buildings like that are built so they can withstand fire, but not indefinitely. The idea is that the fire will either burn itself out or cool off before there is any structural damage. In this case, with all the jet fuel, my guess is that the fire began to soften the steel." The towers, weighing 290,000 tonnes each, were built for 1.5 billion dollars in the 1970s, using a controversial innovation for the time -- a tubular construction with most of the structural support in the exterior "skin." New York architect John Young said the towers were a "vainglorious project" with a number of safety shortcomings that were overlooked because the structures were exempt from local building codes." The building was built far larger than local codes would have allowed," he told AFP. "Many city agencies protested it would be difficult to protect people in an emergency. From day one, it was talked about as a safety hazard." Because of the controversy about the structures, terrorists may have been able to obtain architectural plans to study the weaknesses of the towers. Young noted that the towers utilized the exterior wall framing for lateral bracing, making more room for office space without pillars. "You can see the effect of that when the buildings collapsed, with the lattice framework crumbling and the interior imploding," he said. "The lattice works so long as it remains intact as a system: if a part of it goes, then the whole system goes." But other experts said this system -- also used for the Sears Tower in Chicago and other skyscrapers -- should not be blamed in the collapse. "This type of structure gave those precious minutes for people to escape," said Ben Heimsath, a Texas architect who specialized in building safety." If you take this amount of momentum and velocity and mass and follow it up with a colossal inferno, that is a one-two punch that is an impossible situation." Petroski noted that the Empire State Building survived an impact from a much smaller B-25 bomber in 1945 with no structural damage, but noted that today's buildings are generally lighter and use new methods to allow more open floor space. "In order to build tall buildings economically, you want to make them as light as possible and open up the building," he said. He added that the massive quantities of cascading fuel probably created an inferno that made the collapse inevitable. But he did not think the terrorists had any special knowledge of the building structure. Experts said it is unlikely that design changes will be made to new buildings, but that more attention will be paid to evacuation plans, flammability of materials and fire suppression or sprinkler systems. But Petroski said the attacks will likely dampen enthusiasm for any massive new skyscraper projects. "I think it's going to be very difficult to make a proposal that financiers, the people that supply the money to invest in these buildings, are going to embrace," said Petroski. Tall buildings are built principally as rental space; and you don't want something that makes customers anxious. Right now, going into a tall building is going to have that effect on people." Get 250 color business cards for FREE! http://businesscards.lycos.com/vp/fastpath/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ( Melanggan ? To : [EMAIL PROTECTED] pada body : SUBSCRIBE HIZB) ( Berhenti ? To : [EMAIL PROTECTED] pada body: UNSUBSCRIBE HIZB) ( Segala pendapat yang dikemukakan tidak menggambarkan ) ( pandangan rasmi & bukan tanggungjawab HIZBI-Net ) ( Bermasalah? Sila hubungi [EMAIL PROTECTED] ) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Pengirim: "Fawzi Bin Kassim" <[EMAIL PROTECTED]>