"Three things are to be looked to in a building:
that it stand on the right spot;
that it be securely founded;
that it be successfully executed."
- Johann Wolfgang Von Goethe, Elective Affinities, 1808
Security Magazine's July 2000 cover story featured soaring images
of the World Trade Center (WTC) with the large-type headline: "Never
Again: The World Trade Center fights against the threat of terrorism
with one of the most sophisticated security systems in the world".
The article touts the $60 million response to the 1993 car-bombing
at the WTC, including the installation of bullet-resistant guard
booths, anti-ram barriers, bomb-sniffing dogs, a stopped vehicle
detection system, 15 miles of fiber optics to carry security transmissions,
redundant emergency power, and more. Security planners were meticulous
and thorough in creating a "closed building" under complete
access control; they implemented the best security systems that
money can buy.
On September 11, 2001, airplane hijackers were able to defeat the
original security design of the WTC, the additional post-1993 security
measures, and several different layers of national security defenses
-- including border security, immigration security, intelligence,
air defense, and airport security -- in order to stage a devastating
attack that killed 2750 people and caused the total destruction
of the WTC site in New York City, including the World Trade Center
office towers, commercial and governmental low-rise buildings, and
the hotel, as well as the underground concourse, PATH terminal,
and subway stations. This infamous event occurred despite significant
investments in physical security and access control.
Terrorists have clearly fixated on the WTC target, and it's safe
to assume that whatever replaces the World Trade Center will be
a prime target for a third attack. A complete reckoning of the threats
faced by a rebuilt WTC site is beyond the scope of this essay. There
is no doubt, however, that the design of a new WTC must account
for the active threat model posed by terrorists, who have demonstrated
the willingness and capability to use both cars and airplanes as
A good argument can be made that it is reckless to rebuild the
World Trade Center before the breakdowns in security and life safety
that caused the massive loss of life in 2001 are identified and
appropriate countermeasures are put in place. The idea would be
wait for the results of ongoing investigations by the 9/11 Commission
 and the National Institute of Standards and
Technology (NIST)  and then incorporate the
findings as requirements for the new site design. NIST, for example,
is conducting detailed investigations into relevant topics such
as the Computational Mechanics for Aircraft Impact Analysis and
the Thermal-Structural Analysis of Structural Systems Exposed to
This may be a good argument, but it is not a popular one, at least
not among the half dozen or so New Yorkers to whom I've mentioned
it. There is a widely held sentiment that, unless the center is
rebuilt and life returns to normal as soon as possible, somehow
the terrorists will have "won". Unfortunately, by any
measure, the terrorists "won" the battle fought on September
11, 2001. Then there's the argument that rebuilding the WTC is an
immediate economic necessity. Realistically, the economic recession
has ensured a surplus of high-rise office space in Manhattan --
for the time being, it's uncertain who might rent space in a future
WTC. Finally, there's the argument that it's futile to even try
to prevent or reduce the harm from airplanes flying into buildings.
Yet, special strengthening features are routinely incorporated into
the design of defense facilities, nuclear power plants, overseas
embassies, and other buildings that face a similar active threat
model. The Pentagon was also hit by a jet on 9/11, but there were
far fewer casualties -- this hardened facility was back in business
the same day.
While the rush to rebuild the World Trade Center is understandable
on political grounds -- New York Governor George Pataki wants a
groundbreaking ceremony timed to the 2004 Republican National Convention
in Manhattan -- the rebuilding process is beginning to look like
a security wipeout of historic proportions.
No one can reasonably argue that a fortress should replace the
twin towers. But rather than pretend the threat doesn't exist, it
would be far more reasonable to complete the analysis of the 9/11
security and building failures before committing to a new site design.
It may not be practicable to prevent a large jet from flying into
WTC II, or to build so that the jet would not cause complete building
failure, but perhaps it would be possible to build with enough hardening
and fireproofing to keep the buildings up long enough to evacuate.
And to design dispersed emergency exits so that a single point of
failure does not trap thousands of people in the upper stories.
MIT Professor Thomas Eagar has spoken eloquently to the need to
find a middle ground between the rush to rebuild and security hardening:
If we were to harden everything against a terrorist attack, we'd
push ourselves back into the first half of the 19th century in
terms of living style. Now, some people might consider that an
improvement, but not everybody, so society has some important
tradeoffs here. There's got to be some middle ground where we
can make things more secure but not destroy our standard of living.
The good news is that, despite the rush to rebuild, there is still
time to analyze the 9/11 breakdowns in security and for the architects
and builders of the reborn World Trade Center site to make the adjustments
in their security designs appropriate the threat model, to reach
a middle ground between security and practicality.
See you next issue. 'Til then, keep your guard up.
 See http://www.9-11commission.gov/
A preliminary report can be found at http://www.house.gov/science/hot/wtc/wtcreport.htm
 See http://wtc.nist.gov/
 See http://wtc.nist.gov/solicitations/awards0322.htm
 See http://www.pbs.org/wgbh/nova/wtc/collapse2.html
For general 9/11 info: