By:
August Domel , Jr., Ph.D., SE.,P.E
November 2001
CHAPTER 2: GROUND ZERO OPERATIONS AT THE WORLD
TRADE CENTER
2.1 General
Groundbreaking for construction of the World Trade Center took place on August 5, 1966. Tower One, standing 1368 feet high, was completed in 1970, and Tower Two, at 1362 feet high, was completed in 1972. The structural design for the World Trade Center Towers was done by Skilling, Helle, Christiansen and Robertson. It was designed as a tube building that included a perimeter moment-resisting frame consisting of steel columns spaced on 39-inch centers. The load carrying system was designed so that the steel facade would resist lateral and gravity forces and the interior concrete core would carry only gravity loads.