An article on p. 48 of the April 2, 1964, issue of ENR is chilling upon reading. It begins: “A design procedure that will be used for structural framing of the 1,350-ft-high twin towers of the World Trade Center in New York City gives the exterior columns tremendous reserve strength. Live loads on these columns can be increased more than 2,000% before failure occurs.”
The Seattle-based structural engineer of the towers—named Worthington, Skilling, Helle & Jackson when it won the commission—never suspected that its system, now known as a structural tube, would, some 47 years later on Sept. 11, 2001, save more than 20,000 lives. Thanks to the redundancy, the steel frames of the twin towers absorbed the initial blows of the hijacked jet planes used as missiles by suicide terrorists, rather than collapsing on the impact of planes. The time between the initial impact and the twin towers’ collapses, caused by the fires ignited by airplane fuel, was a critical grace period for most of the estimated 25,000 occupants in the complex that morning. Almost all the occupants below the impact floors escaped.
That same ENR issue featured the WTC engineer, John Skilling, on the cover. The cover line reads: “John Skilling: Architect’s engineer plans the biggest.” A quote from an architect, in the article that begins on p. 124, states: “‘Skilling has the ability to sit down with an architect and sketch out ideas, to think with a soft pencil.’”
Skilling used that ability to win the WTC job, beating out seven New York firms. As the story goes, Skilling went alone to the interview, except for a blank flip chart and a wad of marking pens. Each firm’s interview was supposed to last 45 minutes. Skilling went last. He talked for more than an hour and a half.
Of course, Skilling, his partners and his other colleagues, including Les Robertson, did their homework to prepare for the interview. And Skilling got the interview for the project only because he had a strong association with the WTC architect, Minoru Yamasaki.
Still, it was quite a coup. I don’t suppose the losing firms were too happy about this upstart from Seattle stealing (or steeling?) “their” show! Skilling had not done a building taller than 20-something stories!
John Skilling died in 1998. Unlike Les Robertson, who became the WTC’s project manager and segued after construction into the role of structural engineer for the complex, Skilling was spared witness to the destruction of 9/11. But he also didn’t see the twin towers become “superheroes” that day.