The World Trade Center towers, were believed to be indestructible; because they were all made of steel and built with inner core and outer cores that had trusses attached to the columns. The trusses had a fireproof coating over them; but the plane that hit two World Trade Center towers. made so much fire burn inside, that the fire coatings burned off. So; the trusses were damaged so much that many of them broke off, then the inner core were weakened, so they collapsed making the buildings fall straight down. The water sprinkler systems were damaged and failed from the planes that crashed into the towers. To help building structures of the future; the structures the trusses should have more fireproof coating at the important structural areas, more fire resistant materials should be used and the stairwells should hardened to be more solidly built; in its engineered structural designing. Maybe even outer building fire escape systems can be used, or installed.
Fox & Others Reported Cockpit with Terrorist & Bound Stewardess Bodies Recovered on 911
The Last Hour of Flight 11 Historical Documentary
The Last Hour of Flight 11 - Historical Documentary - youtube.com
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9/11: Phone Calls from the Towers [1/2] - youtube.com
9/11: Phone Calls from the Towers [2/2] - youtube.com
Remembering 9/11 - youtube.com
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Sep 11 - "Why the Towers Fell" - Nova PBS - youtube.com
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