This BBC documentary uses footage of the erection of the World Trade Center, the 1993 bombing, Sept 11 and Ground Zero, graphics of the towers and the planes hitting them, and testimony from survivors, engineers, firemen, and the builder Leslie Robertson.
The WTC was built to overcome what was previously seen as drawbacks to older buildings like The Empire State Building, with a new approach to provide more usable floorspace. This was to make a steel outer skeleton which would bend in the force of the wind, a steel inner core of girders, and steel floor trusses that braced the skeleton to the core. However, the heat-resistant foam that coated the trusses and the drywall plasterboard are what ultimately weakened the towers to the attack, since they both were practically blown away by the jet fuel fire, which weakened the steel.
What is interesting is that while both towers eventually suffered "progressive collapse", as the floors pancaked, each tower fell for a specific different reason. The south tower (which fell first) fell because the outer skeleton snapped, but the north tower fell because the inner core collapsed. The differences were also due to the angles of the planes and the height of the floors that were impacted, and the comparative time that each tower endured their fires. Although experts disagree as to whether different truss connections in the design might have helped the towers withstand the impact, they agree that the length of time the towers stood is remarkable.
Whilst this treatment is primarily concerned with the engineering approach, there are also emotional touches - footage of the doomed inhabitants of the floors above the impact (though no one is seen to jump), the guilt of Robertson, whose office has a view of Ground Zero, and of the firemen who abandoned the south tower after the north fell. We are told that they had only reached floor 26 (they were headed for 93) when the call came to go back, however it seems careless to comment that even if they had reached their destination, there is little they could have done. We hear the story of two men who were trapped in a stalled elevator and who fought through the drywall to escape, and the ghoulish announcement made for workers to return to the south tower before the second plane hit, as some people had evacuated upon hearing of the first plane's impact.
Although the engineering agenda makes the mercenary footage of the burning towers acceptable, draining the color at times seems unnecessary and exploitative.
The WTC was built to overcome what was previously seen as drawbacks to older buildings like The Empire State Building, with a new approach to provide more usable floorspace. This was to make a steel outer skeleton which would bend in the force of the wind, a steel inner core of girders, and steel floor trusses that braced the skeleton to the core. However, the heat-resistant foam that coated the trusses and the drywall plasterboard are what ultimately weakened the towers to the attack, since they both were practically blown away by the jet fuel fire, which weakened the steel.
What is interesting is that while both towers eventually suffered "progressive collapse", as the floors pancaked, each tower fell for a specific different reason. The south tower (which fell first) fell because the outer skeleton snapped, but the north tower fell because the inner core collapsed. The differences were also due to the angles of the planes and the height of the floors that were impacted, and the comparative time that each tower endured their fires. Although experts disagree as to whether different truss connections in the design might have helped the towers withstand the impact, they agree that the length of time the towers stood is remarkable.
Whilst this treatment is primarily concerned with the engineering approach, there are also emotional touches - footage of the doomed inhabitants of the floors above the impact (though no one is seen to jump), the guilt of Robertson, whose office has a view of Ground Zero, and of the firemen who abandoned the south tower after the north fell. We are told that they had only reached floor 26 (they were headed for 93) when the call came to go back, however it seems careless to comment that even if they had reached their destination, there is little they could have done. We hear the story of two men who were trapped in a stalled elevator and who fought through the drywall to escape, and the ghoulish announcement made for workers to return to the south tower before the second plane hit, as some people had evacuated upon hearing of the first plane's impact.
Although the engineering agenda makes the mercenary footage of the burning towers acceptable, draining the color at times seems unnecessary and exploitative.
