Censored Alert: World Trade Center Design Flaws
Via NY Transfer News * All the News That Doesn't Fit
source - Peter Phillips <peter.phillips@SONOMA.EDU>
World Trade Center Design Flaws
Designer/Builder Magazine - November/December 2001
Why the World Trade Center Collapsed: An Architect's Assessment
by Kingsley Hammett
Synopsis by: Chris Salvano, Sonoma State University
Among the more shocking images of September 11th was the sight of the
World Trade Centers collapsing into rubble in a matter of seconds.
Why did both towers of the World Trade Center, set afire in their
upper floors, collapse to the earth? San Francisco architect and
welder Jim Malott explains his assessment of intrinsic design and
construction flaws of the towers which hastened their complete
collapse.
Malott holds a bachelor's degree in pre-architecture from Stanford, a
master's degree in architecture from the Harvard Graduate School of
Design. Malott has studied the properties of steel-reinforced
concrete from graduate courses at the University of Delaware. He is
also a skilled welder and a practicing architect in the San Francisco
area, where he has helped design a number of high-rise buildings.
Malott has also chronicled and photographed the towers' birth from
the mid-60's to its rise and construction in the 70's.
According to Malott, before the advent of the World Trade Center
towers, high-rise buildings shared two vital characteristics: one,
they were supported by a grid of steel columns, and two, the columns
were encased in a tough cladding of reinforced concrete. This
concrete created a fireproof skin designed to withstand a four-hour
inferno. (The four-hour rating is a building industry standard for
fireproofing) As designed by architect Minoru Yamasaki the Twin
Towers incorporated neither of these traditional features. These
features were found in most tall buildings before the Twin Towers
came along and changed the equation. Malott claims that it was the
failure to use the traditional steel column grid design and concrete
coating on the steel columns that was the fatal flaw of the
buildings--not the initial crashes, not the exploding jet fuel and
not the subsequent fire alone.
In an attempt to cut weight--which is the enemy of all high-rise
buildings--the designers of the Towers eliminated the traditional
steel column grid. Instead, Yamasaki placed the steel columns in the
perimeter of the outer walls of the buildings and in the perimeter of
the small inner core of the buildings that housed the elevator
shafts. This design allowed every floor to have unobstructed floor
space with no interior supporting columns or beams.
In further attempts to save weight, time and money designers were
allowedto fireproof the steel columns with spray-on mineral-wool
fiber and layers of sheetrock instead of the traditional method of
using reinforced concrete. The elevator shaft and the steel columns
in those shaft walls were covered with sheetrock as well.
Yamasaki and his engineers had indeed calculated the impact of a
commercial jetliner shearing into the World Trade Center. Even a
jetliner flying at 300 mph isn't an overwhelmingly heavy load
according to Malott. The mass of a 767 aircraft is less than half
the mass of one floor of the building. What wasn't calculated says
Malott was a commercial jetliner shearing into the World Trade Center
and stripping the sheetrock fireproofing off the steel columns and
the elevator shaft. "The culprit was not the jet fuel," which Malott
has so often reiterated in the wake of the disaster. "I say that as
a formal naval officer who witnessed a number of catastrophic
aircraft accidents. Jet fuel vaporizes and ignites instantly. The
real culprit was that all the fireproofing was blown off on impact."
And since the Towers didn't have supporting columns and beams, the
unobstructed floors allowed the bodies of the planes to crash into
the elevator shaft core. This in turn destroyed the shaft walls, its
fireproof sheetrock and any hope that the building would survive a
four-hour fire. The exposed steel immediately became vulnerable to
structural failure and it took less than one hour to heat the
unprotected steel to the failure point.
Malott also notes the questionable quality control of some of the
welding in the buildings. Malott noted that during construction in
the 70's each exterior column section was bolted temporarily, three
in a row, then later welded in place. Photos after the collapse
showed that dozens, perhaps hundreds, of these welds failed. The
columns fell three in a row, just as they had been built. "All of
these decisions made back in the 60's were the precursor of this
tragedy," claims Malott.
Malott explains that designers must return to cladding their steel
columns with reinforced concrete or some other tough substitute
rather than fragile sheetrock. Ever since the World Trade Center
pushed the limits of design, most high-rise buildings in America have
followed its lead. Most wrap their steel columns in some combination
of mineral wool or gypsum board rather than concrete. This leaves
many of these buildings potentially susceptible to the same type of
structural failure.
Peter Phillips Ph.D.
Sociology Department/Project Censored
Sonoma State University
1801 East Cotati Ave.
Rohnert Park, CA 94928
707-664-2588
http://www.projectcensored.org/ 
12:23 AM Dec 2
