Engineering failures offer valuable lessons when set in historical and current context.
I have long advocated focusing on failure as a means of improving the likelihood of success in design. If designers do not properly anticipate how a structure or system can fail, then they may inadvertently incorporate a critical latent flaw into their design.
One effective means of bringing the idea of failure into the classroom is through the use of historic case studies, preferably ones that have a strong narrative component that will engage students at several levels: individual, social, cultural, technical, ethical. The 1986 failure of the space shuttle Challenger has become a classic example, with the conflict between engineers and managers providing the kind of dramatic tension that helps students remember the facts and issues.
The 1981 collapse of the Kansas City Hyatt Regency walkways provides another excellent example, one whose technical details are so elementary as to be accessible even to students who have not yet had a course in strength of materials. Incidentally, the fact that the engineers involved in the design of the structure lost their licenses because of their casual acceptance of a deceptively simple design change opens the way for a discussion of professional registration and responsibility.
Such case studies may be categorized as recent history, incidents that remain fresh in the minds of engineering professors who might recall having seen them reported on television and in newspapers. However, chances are that today’s first-year engineering students were not even born when these infamous incidents occurred. It is thus important to remember, in teaching such cases, the necessity of providing an introduction and background that will make them understandable in context.
The same caveat applies even more so to case studies from ancient times, the Renaissance and the nineteenth century—periods from which I have drawn what I believe are effective examples for emphasizing that design is a timeless endeavor and failure an ageless problem. Indeed, we can learn a great deal about design from failures whose cases are long closed rather than the subject of ongoing debate or litigation.
Such reasons were among those that motivated the History and Heritage Committee of the American Society of Civil Engineers, which I chair, to recommend that history and heritage be among the educational outcomes expected of a 21st century civil engineering education. However, ASCE’s Body of Knowledge Committee elected to recommend an outcome that grouped together “Contemporary Issues and Historical Perspectives.”
Many of us were disappointed that our recommendation was folded into a seemingly a-historical context. However, upon reflection, I think the combination provides an excellent rubric for emphasizing the relevance today of case studies from both the distant and the recent past.
In fact, I have long sought to combine discussions of historical case studies of failure with contemporary ones. In a seminar this past semester I thought it would be instructive to discuss not only the classic cases of the Tacoma Narrows Bridge—whose tortuous last moments were captured on film—and the Silver Bridge—which collapsed into the Ohio River in 1967—but also the terrible structural failure of last summer, the collapse of the Interstate-35W bridge in Minneapolis, with which I expected the students to be fully familiar.
To my surprise, only 1 out of 15 students vaguely remembered some structure collapsing in August 2007. Evidently, most of today’s students do not follow the news; one even offered without apparent embarrassment that he did not “keep up with things.” It was my mistake not to anticipate this pedagogic failure mode, but I will learn from it how more effectively to combine discussions of contemporary issues with historical perspectives on failure.
Henry Petroski is the Aleksandar S. Vesic Professor of Civil Engineering and a professor of history at Duke University. His book, Success through Failure: The Paradox of Design, was recently issued in paperback.