Alto Weekly Online Edition
Sept. 11, 2001, 4 p.m.
Stanford expert: Planes hit twin towers with
World Trade Center built to withstand airplane
by Jennifer Deitz Berry
The World Trade Center Towers were designed to withstand being
hit by an airplane, according to Stanford University Professor Steven
Block is a professor of applied physics and biological sciences
and an expert on national security and terrorism. He spoke at a
press conference this afternoon on Stanford campus.
According to Block's calculations, the energy generated by a fuel-laden
Boeing 757 or 767 colliding into a World Trade Center tower is roughly
equivalent to one-20th of the energy of the atomic bomb dropped
on Hiroshima, Japan on Aug. 6, 1945.
"It's a staggering amount of energy," Block said. "Any aircraft
is essentially a flying bomb."
According to Block, the World Trade Center twin towers were designed
to withstand "enormous impacts," including being hit by a hurricane
or an airplane.
Block said he doubted there were any structural flaws in the design
of the twin towers. The plane could have inflicted major structural
damage to the periphery of the towers, including passing through
an entire floor or knocking out the steel girders on the outside,
and still the towers would have remained standing.
What most likely caused the buildings to collapse was damage to
the building's steel core, Block said, though acknowledging that
his expertise does not extend to mechanical engineering.
Block said the explosion appeared to have "heated the core of
the building to such a degree that it began to melt." When the melting
steel core could no longer support the hundred or more floors above,
the buildings collapsed.
Ignited fuel generated 90 percent of the energy in the explosion,
Block said. A Boeing 767's fuel capacity is roughly 23,980 gallons,
and a Boeing 757 carries roughly 11,466 gallons of fuel.
Block said it was a likely possibility that terrorists had intentionally
taken over planes scheduled to travel across the country because
they'd be carrying more fuel and would therefore cause more devastating
explosions upon impact.