Henry Petroski’s early focus was on the ideas and experience of civil engineering, but surely he became influential to all types of engineers over a long public career. He died June 14 in Durham, N.C. at 81.
As a Duke University professor, Petroski looked closely at the art and science of engineering, and I think he came up with some very meaningful conclusions. Studying the history of failures in rockets, buildings, bridges and the like was his special pursuit. His books include “To Engineer is Human,” “The Evolution of Useful Things,” and “The Pencil.”
My take-away from seeing him lecture and appear on TV, and from reading his books and Scientific American articles was this:
Styles of engineering come into use, formulated by individuals who learn first principles from (often painful) failures. Then the style becomes taken for granted. Successive engineer generations push the barriers of the basic style, and mistakes are made that are sometimes deadly.
Among the object lessons in engineering failures Petroski would often cite were the failure of the elevated skywalks at a Kansa City Hyatt Regency hotel, the collapse of the Tacoma Narrows Bridge in Washington State, the collapse of the Twin Towers of the World Trade Center in New York as the result of deliberate terrorist air crashes, and the loss of two NASA space shuttles.
His writing could take the form of excessively fine-grained pedanticism – I couldn’t forge through “The Pencil” history. Still, thanks to Petroski I did learn that its history was much about finding the right combination of graphite and clay – and I continue to study the pencils I sharpen with particular attention.
Interesting to learn in the New York Times obituary of Petroski’s childhood recollection: Making towers and bridges out of pantry cans and boxes. Guess he caught the analytical bug early!
I had the opportunity to interview Petroski very briefly after he spoke to a hall of software engineers at the OOPSLA Conference in Tampa in 2001. This was just a few weeks after 9-11, when the airways had just reopened, and a pretty tense time for travel. I recall that he was open to our questions. The assembled object-oriented programming crowd was enthralled, and the questions in the scrum after his speech were questions without clear answers at that time. Engineers ask questions, and wonder, especially about catastrophic events.
I don’t find raw notes on that long-ago interview, but mark here that, when the new World Trade Center was built, there was far more use of concrete that is less pervious to conflagration.
I did find a write-up I did for Application Development Trends on Petroski at OOPSLA. I will include a bit of that and a link. I tried to draw engineering principles from his studies that might apply to software architecture issues of the day, though that bit sounds weak. There were things to be afeared of in the burgeoning architecture of web services – but not the ones I imagined/predicted in 2001.
I can’t read this piece without thinking of my indebtedness to the great crew at ADT, led by the late Mike Bucken, who gave me so many opportunities to damn the torpedoes and get something interesting out there to our readers. The list of editors that would let me run the headline “There’s No Success Like Failure” is pretty short. – Jack Vaughan
From “There’s No Success Like Failure” on adtmag.com
If you interviewed a system designer who admitted to his or her list of failures in design, you would probably begin plotting ways to end the meeting and get to the next job candidate, wouldn’t you? You probably wouldn’t consider hiring the person.
An obsession with failure could be a problem, but a modicum of fear of failure—a respect for the phenomena that can undo a design—may be healthy in a designer or developer. Maybe you should hear out a job candidate who is capable of analytically discussing a failed project or two.
If you are wary of this advice, I don’t blame you, but you might be more inclined to follow it if you were to hear from Henry Petroski. This Duke University professor of history and civil engineering spoke at last fall’s OOPSLA Conference in Tampa, Fla. In a kick-off keynote address, Petroski discussed success and failure in design throughout history, concluding that there is a unique interrelationship between the two.
“All materials are flexible if slender enough,” asserts Petroski, who noted that designers in bridge design tend to go toward the sleek and aesthetic as they get further away in time from the first principles. The Tacoma Narrows Bridge breakup of 1940 stands—well it doesn’t exactly stand, it fell—as a testament to Petroski’s assertion.
Scholar Petroski took his OOPSLA audience back to ancient Rome to make his point. He discussed Vitruvius. That author of key architecture texts went to great length to consider failures of stone-and-axle variations (that’s how they moved pillars) of the day. Vitruvius suggests that following a successful design to an ultimate conclusion is not the way to proceed.
The big ships, many failed, of the era of European exploration came in for consideration. “Ships made of wood were scaled up, every dimension doubled,” said Petroski. “At a certain size, they would break in two.”
Petroski noted that nature does not design this way (to blindly scale up); the leg bones of large and small animals are not exactly proportional. Cable stay bridges are now the rage in bridge design, noted Petroski. Their design is becoming increasingly ambitious, he added, and some failure may be in store.
“Failures in bridge style seem to repeat in 30-year [intervals],” said Petroski. “Engineers are ambitious. Everyone wants to build the largest bridge in the world. Cable stay bridges are exhibiting problems.”
Whenever the envelope is pushed, he indicated, “there is opportunity for phenomena to manifest that were not obvious in the small.”
Failure could be generational, said Petroski; when engineers start to work with new design paradigms they take great care. Then as things get familiar, they forget about the fundamentals and they push, sometimes beyond the real design limits.
RELATED
Petrowski speaks – YouTube
Obituary – New York Times
Read the rest of “There’s No Success Like Failure” – ADTmag.com Jan 2002.