Very
interesting interview with the Charles
Maikish, director of all 7 buildings of
the WTC complex in science/engineering
magazine Popular
Mechanics in 1993
following the first terrorist attack on
the complex.
Pillars of strength
The wreckage was greater than anyone could have imagined, Maikish recalls. But the World Trade Center was in no danger of collapsing. "No other structure, no complex would have withstood that kind of blast," claims Maikish.
After all, the giant buildings are designed to resist a once-in-a-century wind blast of 150 mph. Each tower can sway up to 3 ft. in heavy winds. The instruments that record this swaying registered nothing from the explosion. The structures were also engineered to soak up the impact of a Boeing 707, the biggest plane in the skies when the towers went up in the late 1960s.
This unique strength arises from the towers' unique steel curtain walls, the exterior frames designed by architect Minoru Yamasaki. Twenty-one steel columns, spaced 10 ft. apart and braced with horizontal spandrels, make up each facade of the towers. These are the main load-bearing components of the structures. True, the explosion did not occur within the footprint of either building, but even the loss of 10 columns in a tower could not have triggered a collapse says Fasullo.
World Trade Towers 1, 2, 7 are all a true indictment of USA's engineering capabilities. After-all, a simple fire brought down building 7, and buildings 1 and 2 are examples of what an upper floor fire can do on ANY reinforced-steel building...
Reply