Engineer looks at structure of World Trade Center
Structural engineer of the World Trade Center, John Skilling, designed 110-story buildings to withstand the impact of a commercial airplane.
Skilling’s firm, Skilling Ward Magnusson Barkshire, had to test the twin towers against every danger possible. When they were completed in the early 1970s – for structures made of steel and glass – the buildings were an unprecedented size.
Skilling told The Seattle Times in 1993, “We looked at every possible thing we could think of that could happen to the buildings, even to the extent of an airplane hitting the side.”
Skilling’s team proved in an analysis, the towers would withstand the impact of a Boeing 707, weighing 248, 000 pounds and measuring 144 feet. The first commercial airplane that hit the World Trade Center on Tuesday, was a Boeing 757, weighing 220,000 pounds and roughly the same length.
The staff said to The Seattle Times, “Our analysis indicated the biggest problem would be the fact that all the fuel [from the airplane] would dump into the building [and] a lot of people would be killed.”
However, Skilling said, “The building would still be there.”
But after the terrorist attack on the twin towers in Feb. 1993, in which 6 people died and 1,000 were injured, Skilling admitted to The Seattle Times “back in those days [the 1970s] people didn’t think about terrorists very much.”
He credits the strength of the twin towers withstanding the 200-pound car bomb of the 1993 attack to closely spaced supporting columns. Although, Skilling still admits to The Seattle Times, “I would imagine that if you took the top expert in that type of work [explosives] and gave him the assignment of bringing these buildings down . . . I would bet that he could do it.”
Trained hijackers proved Skilling right in Tuesday’s attack as the World Trade Center collapsed.
Jon Magnusson, who succeeded Skilling as chief executive of the engineering firm, told The Seattle Times in 1998, structural engineers aren’t usually as well-known as the architects, but “when something bad happens, that’s when the structural engineer becomes famous.”
Nevertheless, Skilling is known for many positive accomplishments. He is credited with the structural design of more than 1,000 buildings in 36 states and 27 countries, including the Pacific Science Center for the 1962 World’s Fair, the original 50-story Seafirst Building and Seattle’s tallest building, the 76-story Columbia Seafirst Center.