Why the Towers Fell

NOVA presents an exclusive scientific look at the American Society of Civil Engineers' report of why the World Trade Center collapsed. NOVA's "Why the Towers Fell" airs Tuesday, April 30, 2002, at 8 PM ET on PBS.

For most Americans, the image of the collapse of the World Trade Center
Towers was not only a scene of unforgettable horror, it was a moment of
unimaginable consequence. Who could have guessed that a steel behemoth of
such size and strength-a building so massive that it had its own zip
code-could actually be reduced to 150 feet of dust and rubble? NOVA offers
viewers an exclusive look at the American Society of Civil Engineers' (ASCE)
report into the root causes of the Towers´ collapse by following a team of
structural and fire engineers during their fascinating and intricate study.
NOVA's cameras were allowed exclusive access to the team of twenty-five ASCE
engineers as they studied the remains of the buildings that fell on September
11. NOVA presents Why the Towers Fell, Tuesday, April 30, 2002, at 8 PM ET
on PBS (check local listings). The ASCE final report is tentatively
scheduled for formal release by the Federal Emergency Management Agency
(FEMA) May 1, 2002.


In the aftermath of the collapse, the questions came quickly and urgently:
was it inevitable that such a severely damaged structure would completely
collapse? Or was there something about the building´s design or construction
that made it especially susceptible to failure? What exactly caused that
failureâ€-fire, heat, internal damage? Was the evacuation plan adequate
enough to save the maximum number of lives? And are other tall buildings just
as vulnerable to collapse when the blast is great and the fire uncontrolled?
In the gray wasteland of smoke and dust and mangled steel that was once the
third tallest building in the world, forensic engineers began sifting the
wreckage for clues and answers to these and other structural truths. This
blue-ribbon team of engineers is nearing the end of its task, and NOVA has
been there from the beginning, following its investigation of the causes of
the calamity. Why the Towers Fell presents the engineers´ conclusions in the
most definitive explanation yet of how and why the towers collapsed.


But the Twin Towers weren´t the only buildings that collapsed. Standing well
over a city block from Trade Center Tower #1, a forty-eight-story glass and
steel structure known simply as Building #7 did not seem to suffer structural
damage from the collapsing towers but nonetheless crashed to the ground after
several hours of severe and uncontrolled fire. Since Building #7 is a typical
glass and steel building and seems to have collapsed from fire alone, does
this mean that office workers the world over are far more vulnerable than
anyone ever imagined?


Featuring many of this country´s best structural engineers including Gene
Corley, the lead investigator on the Oklahoma City bombing; Charles Thornton,
the builder of the Petronas Towers (the world´s tallest building); and Mark
Loiseaux, the leading expert on the "purposeful" demolition of big buildings,
the program takes viewers through the process by which these professionals
came to understand the how´s and why´s of one of modern America´s greatest
tragedies. Also presented are several of the buildings´ survivors, who tell
compelling real-life stories of their harrowing journeys to safety, including
three firemen who miraculously escaped death as Tower #2 collapsed around
them. This NOVA will feature rare, video-enhanced footage showing details of
the buildings´ structural damage never before seen on TV, and detailed
animation sequences that let viewers "see through" the buildings to the
damage that had occurred inside.