Infrastructure and Human Fallibility

By August 9, 2007Infrastructure

The excellent blogger Varifrank, a software engineer by trade, points us to a book in this post that looks promising, “To Engineer is Human: The Role of Failure in Successful Design,” by Henry Petroski. While Varifrank declines to point fingers for the Minneapolis bridge collapse — and there is way too much of that early blame-fixing by callous exploiters seeking political advantage — he does have this say about the book:

The book recounts several large scale engineering failures and how many of them were caused by simple, small never before seen and often overlooked errors. I don’t know what caused this event and I don’t think anyone does, but I suspect that we may be looking at something that will eventually end up in the second edition of Mr. Petroski’s book.

Petroski, a professor of civil engineering and history at Duke, had an op-ed in the The Los Angeles Times last week, “Learning from Bridge Failure.” Conclusion:

No matter how carefully bridge designers anticipate failure on the drawing board (or computer screen), their structures will only be as reliable as how carefully built, maintained and inspected they are. Just because a bridge has given decades of successful service under adverse conditions of increasingly heavy traffic and neglect does not mean that it will continue to do so. It is the function of regular and careful inspections to catch what designers might not have anticipated.

In the wake of Minneapolis, there will no doubt be renewed vigilance. More careful inspections and more conservative interpretations of their findings may cause some immediate inconveniences, but they will also likely prevent some imminent failures.

In bridge design, as in all structural engineering, success can breed hubris and catastrophe, while failure nurtures humility and caution. Unfortunately, it does seem to take a collapse to re-sensitize inspectors and operators to the real dangers that lurk among rusting steel and cracking concrete. Let us hope that the lessons learned in Minneapolis are not forgotten once more.

There’s good, implicit advice in there for all of us entering the policy debate about infrastructure: Practice humility and caution.

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