Evolution of Technology (TEC 154 2014S) : Readings

Petroski, Chapters 8-13


Petroski, Henry (1992). To Engineer is Human: The Role of Failure in Successful Design. Vintage. Chapters 8-13.

In chapter 9, Petroski talks about how engineers look at the structural soundness of structures that have been built multiple times and are not faulty. He then points out that engineers go on to readjust the safety margins for sound structure. Whatever happened to the "if it aint broke, don’t fix it" mentality? How would these engineers address that theory? [Fair. Doesn't Petroski address this issue? Approximately, "For reasons of cost ..."]

On page 100, Petroski states that safety and economic factors are directly correlated. This leaves me to question how strong of an impact economic factors have in the safety and the structural soundness of the structure? Also, if finances compromise the safety of a structure, should the structure still be produced? [Mixed. We can't really answer how much of a factor the do have, since we aren't privy to corporate decisions. On the other hand, we could consider how much of an impact they should have. And, as we move forward to discuss this question, isn't it nice to know that we have economists in the class? This should be a good question for them.]

On page 87, Petroski talks about the way that failure allows us to explore different alternatives to produce new technology. He states, "Thus the walkways as originally designed, though not as strong as they should have been, would probably not have fallen, and their nonconformity with the code might never have been discovered." What problems does this quote intrinsically produce? [Mixed. The "intrinsically produce" is a bit weird. You should be able to find a better way to phrase it.

In Chapter 9, safety in numbers is discussed. Petroski discusses how "excessive strength" is unattractive, uneconomical, and in some cases, unnecessary (pg 99). Thus, engineers have to consider what is strong enough by considering architectural designs, financial factors, and political factors. Here, I have two questions: A) Can something built be regarded as too strong? B) How has evolution in technology changed our idea on what is considered strong or not? [Good.]

In chapter 10 Petroski discusses how 50%-90% of structural failure results from crack growth. This is important due to the corrosion of bridges currently happening. Is it possible that many more bridges could start failing soon due to crack spread and poor maintenance? [Fair. This isn't really something we can answer, given our expertise. But it could probably be phrased in such a way that it's worth considering. For example, you might have Googled a recent report on bridges.]

In chapter 13 Petroski discusses innovation with this quote "if an inspired design relies on sound principles and does not try to extend the limits of art or engineering too far too soon, it stands a good chance of joining the canon of success." Is it notable that Petroski included art into this quote, when we tend to think of success as the building/bridge not failing? [Good, or at least good enough. Petroski does note early on that he thinks of Engineering as both an Art and a Science.]

Can we explain "factor of safety" and its relevance to design? Do we make use of this idea in other “human” areas of life? [Mixed. A bit muddled in the phrasing, but I like the second half of the question.]

Petroski seems to determine that engineering failures are on the whole a necessary and even beneficial thing. How might his point of view or critical framework bias his opinions? Are there things he’s overlooking, intentionally or otherwise? [Very good. Given that he talks about the things engineers overlook in their designs, it's a great question to ask about him.]

The Hyatt Regency Walkway example that Petroski discusses in chapter 8 (Accidents waiting to happen) reveals the detail-oriented nature of engineering and construction. With increasing attention being paid to design and aesthetics of buildings, can we expect new buildings now to be safer than before or not? Can the weak links be identified among the many other minute details involved in construction? [Mixed. While it might be worth considering, is this a question that we can really answer?]

Do economic and political factors hinder the decision-making process of an engineer about whether a construction is safe enough or not safe enough? [Fair. Do we have enough data to make such an analysis? Could also be contextualized a bit more - What does Petroski say about such factors? And isn't the obvious answer "Of course economic and political factors hinder the decision-making process"?]

Can engineers ever be certain that their products will be reliable, despite how meticulous they are with their design? (e.g. without flaws, cracks, instability, etc.) [Fair. Do we really know what engineers know? And isn't the obvious answer "No"? Could be improved by acknowledging imperfection. For example, "Petroski notes that engineers can never be certain that there designs are reliable, no matter how meticulous they are. For example, insert quotation. Given that no designs are guaranteed to reliable, how should an engineer (or how should society) ensure that a design is reliable enough?"]

Do you agree with Petroski when he says that there should be no expectation that there will ever be a "final bridge"? Will engineered structures ever reach a standard design or will they remain fluid? [Mixed. I don't think this is so much a matter of agreeing with Petroski as Petroski convincing you. And, perhaps, you might ask if we can envision an engineered structure that will end up with a standard design and not continually evolve.]

On page 114, Petroski defines the "safe life criterion," but it was a little unclear. What might be a better way to define it? [Good. Asking us to think more about his particular language in an important part of the book is quite appropriate.]

In Chapter 8, Petroski more specifically discusses the need and/or inevitable habit for people to use new technologies as they come out or become the standard in our society. But do engineers really need their new technologies to be tested and worn to the point of failure to improve and make progress? Could the refusal to use certain technologies by people based on fear or pre-established habits provide more or sufficient enough of an idea of failure for improvements to be made? [Very good. Asks for other kinds of "failure" (even if you didn't phrase them that way).]

Copyright (c) 2014 Samuel A. Rebelsky.

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