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To: Think4Yourself who wrote (51487)	5/18/2006 5:59:43 PM
From: sciAticA errAticA	Read Replies (4) \| Respond to of 116555

re: steel was apparently encased ---------- ... you're referring to concrete encasement fire protection. This concrete is NOT structural - this is one form of fire resisting material that is required to be applied to all exposed structural steel. Impact likely did jar some of the coating off -- in the proximity of the crash. However, even if this were to cause localized failure - a proposal to which I would take exception for reasons I've noted - how would this explain the failure, shearing off and projectile removal of all built-up plate steel core columns, for all of the dozens of floors below plane impact? Very simply, and at the very least, the skeleton of core steel columns should have remained standing -- with the collapse of the light gauge steel truss floor pans collapsed and pancaked around the still-standing core skeleton. .. and not to repeat myself, but the fire was relatively cool, and certainly short in duration when compared to other structural steel building fires, which have lasted for days - some with loss of fire resistant coatings. Structural steel requires consistent, high furnace, longer term temperatures (than what we evidenced on 9/11) to lose its structural viability for specified loads -- then add to that the over design that is integral to sizing calculations. I would again emphasize that, aside from WTT1&2&7 assertions, no other steel building has ever collapsed from fire. Many steel buildings, as well, have less durable fireproof coatings that are indeed rather delicate and easily frangible -- rendering the WTT1&2 superior, and potentially more resilient against loss of fire coatings -- than other steel buildings that have caught fire and survived.

To: Think4Yourself who wrote (51487)	5/18/2006 7:23:56 PM
From: Elroy Jetson	Read Replies (1) \| Respond to of 116555

The primary purpose of sprayed concrete on steel girders is to protect the steel from heat in a fire. It does not provide structural strength. This random website lists these possible problems. public-action.com lack of insulation Some have raised questions about the degree of fire protection available to guard the structural steel. According to press reports, the original asbestos cementitious fireproofing applied to the steel framework of the north tower and the lower 30 stories of the south were removed after the 1993 terrorist truck bombing. higher temperature than estimated due to exothermic destruction of aluminum Others have pointed out the possibility that the aviation fuel fires burned sufficiently hot to melt and ignite the airliners' aluminum airframe structures. Aluminum, a pyrophoric metal, could have added to the conflagrations. Hot molten aluminum, suggests one well-informed correspondent, could have seeped down into the floor systems, doing significant damage. "Aluminum melts into burning 'goblet puddles' that would pool around depressions, [such as] beam joints, service openings in the floor, stair wells and so forth...The goblets are white hot, burning at an estimated 1800 degrees Celsius. At this temperature, the water of hydration in the concrete is vaporized and consumed by the aluminum. This evolves hydrogen gas that burns. Aluminum burning in concrete produces a calcium oxide/silicate slag covered by a white aluminum oxide ash, all of which serve to insulate and contain the aluminum puddle. This keeps the metal hot and burning. If you look at pictures of Iraqi aircraft destroyed in their concrete shelters [during the Persian Gulf war], you will notice a deep imprint of the burned aircraft on the concrete floor. .

To: Think4Yourself who wrote (51487)	5/18/2006 8:24:15 PM
From: tdl4138	Read Replies (1) \| Respond to of 116555

There are some pretty credible experts that have compiled tons of information on the 9/11 Twin Towers and how/why they collapsed. The site is st911.org When I first found the site I spent hours reading, listening and viewing. I would highly recommend that anyone questioning the government report as to why the buildings collapsed pay a visit. Pay attention to what the structural and metallurgical engineers think happened...and what they think of the 9/11 commission report. If you take the time to go over all the independent reports that are compiled here, the most important aspect to consider is the caliber of the people putting them together. If this site has been posted here previously, I apologise.

To: Think4Yourself who wrote (51487)	5/18/2006 8:25:14 PM
From: Webster Groves	Read Replies (1) \| Respond to of 116555

<The experts said that the fire combined with the impact would likely crack and pop the concrete off of the steel and that could cause a collapse of the building.> Well. that's one opinion. The NYFD apparently thought otherwise because they were still sending men UP the towers at this time. I haven't heard if NYFD entered WT7, but apparently no one was hurt there. As the CIA NY headquarters, everybody probably had the day off "for some reason". wg