Monday, September 12, 2005


There continues to be a large amount of conspiracy theory nonsense on line about the destruction of the World Trade Center towers. Yet another diary at Kos covers the so-called "controlled demolition" of the buildings. Let me take a little of this on:

Do steel frame buildings just collapse neatly down into their own footprint, and, at free-fall speed due to a fire? or heat? When in all of world history has that ever happened before?

The Trade Center towers hardly collapsed "neatly down into their own footprint"s. Aerial photographs of the site show that wreckage from both towers fell all over the area. The Marriott hotel was almost cut in half by wreckage falling from the South Tower (photographed before Tower 1 fell); buildings all over the area ended up with varying degrees of damage, some crushed, others with pieces of WTC steel and facade parts sticking out of them. Controlled demolition is designed specifically to avoid flying wreckage and buildings falling onto other buildings. As for "free fall," it's largely an illusion that the buildings fell that fast, caused by the huge clouds of dust that immediately arose and blanketed the area. Both buildings suffered failures in the impact zones that did cause the tops of the buildings to come down rather quickly, but in both cases study of videos and photographs show that large portions of both buildings survived the initial collapse only to fall some seconds later, including what appears to have been almost the entire central core below the impact zone of Tower Two. These are hardly "neat" textbook-style controlled collapses.

Even the foundation and framing of wood-made houses remain standing after a 1-hour fire.

The 2nd tower fell first even though it had only been on fire for a little over 1 hour. What are you going to believe that the marvelous WTC which were designed to handle tremendous fire, wind, and impact forces simply just fell down like a house of cards from a 1 hour fire?

Indeed, no steel framed building until 9/11 had fallen from fire. But fire was only part of the 9/11 story. The fire was preceded by two large, heavily loaded jet aircraft tearing the guts out of the buildings, severing steel core columns and tearing holes in floors and, perhaps even more importantly, blowing fireproofing off of the steel columns and the trusses that made up the floor system. After impact, the buildings were already badly crippled. Fortuitously, the hat trusses at the tops of the buildings, intended to support a transmission antenna (WTC 1 had such an antenna; WTC 2 was designed to carry one if necessary) were able to redistribute some of the load from the damaged core columns to the walls of the buildings, giving the buildings stability. But the kerosene-fueled fires - and conspiracy theorists tend to understate the intensity of these fires - were relentless. I would recommend that everyone interested in this subject read the NIST reports on the disaster and especially their detailed studies (large pdfs here and here) of the fires. The fires were so hot that WTC 2 bled molten aluminum from the airplane that hit it for several minutes before it collapsed. The fires caused the floor trusses and surviving core columns to bend, actually pulling the walls inward by not inches but feet. When the walls, already carrying many times their normal load, finally failed, the buildings fell.

Part of the problem with 9/11 is that the way the disaster was handled invited conspiracy theories. For example, the mad rush to clear the site made the task of scientists studying the disaster much harder (in particular WTC 7 was cleared away so quickly that NIST could not obtain any steel samples from that building). Once it was clear that there were no survivors, the clearing should have turned into something a little closer to an archeological dig, which I suspect would have led to a better understanding of the disaster, the recovery of more remains, and very possibly the recovery of the black boxes from the aircraft. As it was, the wreckage was hauled, scooped, and dumped into ships to take it overseas at a truly ridiculous pace. The failure to involve the NTSB was also a mistake. NTSB investigators should have been onsite identifying parts of the airplanes. It's not impossible that such an approach could, again, have turned up some of the CVRs and flight data recorders.

No one in the US government "controlled-demolished" the World Trade Center. The real crime here is that the man responsible still walks this earth: Osama bin Laden.


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