(Email sent on Thur 15 Sep 2011 to editors@sciam.com)
Dear Editor of Scientific American,
Your September issue included the piece "Castles in the Air" by Mark
Lamster where the failed prophecy that the attacks of 9/11 were to end
the age of the skyscraper is discussed.
The article highlights that 2011 will be the single greatest year for
the construction of tall buildings in history. That China is leading the
skyscraper boom, yet their engineering design is dominated by American
firms.
The article discusses design issues on evacuation. But the World Trade
Center was designed to evacuate rapidly, and so both towers WTC1 and 2
did below the impact floors on 9/11. WTC7 was also
evacuated in time.
The article also discusses design issues on aircraft impact. But the World Trade Center was designed to withstand the impact of a large aircraft, and so both towers WTC1 and 2 did on 9/11. They collapsed because of fire. WTC7 was not hit by an aircraft, but collapsed due to fire as well.
The article also discusses design issues on aircraft impact. But the World Trade Center was designed to withstand the impact of a large aircraft, and so both towers WTC1 and 2 did on 9/11. They collapsed because of fire. WTC7 was not hit by an aircraft, but collapsed due to fire as well.
The article goes to imply that the design of tall buildings for
protection against terrorist attacks is mostly about aircraft impact and
evacuation. It does not discuses fire. But WTC 1, 2 and 7 collapsed
because of fire. So they only issue that is not addressed in the article is the one that
brought World Trade Center down, and the one where design advances over
the past decade have been most marginal.
This is a thin favour to fire
engineering and to the safety of tall buildings.
--
*Dr Guillermo Rein*
Senior Lecturer in Mechanical Engineering
University of Edinburgh
http://www.eng.ed.ac.uk/~grein
"so easy it seemed, Once found, which yet unfounded most would have
thought, Impossible!" J Milton
UPDATE Sept 2011: This letter was followed by two more from Dr Bisby and Hilditch
UPDATE Dec 2011: The letter of Dr Bisby has been published in the December 2011 issue of Scientific American.
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