TCS Daily


An Engineer's Dreams

By Nick Schulz - December 12, 2005 12:00 AM

Editor's note: Henry Petroski is professor of civil and environmental engineering at Duke University and the author of Pushing the Limits: New Adventures in Engineering. He recently spoke with TCS editor Nick Schulz.

Nick Schulz: In your recent book Pushing the Limits: New Adventures in Engineering, you mentioned "battles between technological developers and environmental conservationists." Are these political battles inevitable whenever there is an engineering or technological project, or are there ways around these kinds of fights?

Henry Petroski: I think the larger the project, usually, the more likely there are to be political battles. They don't always have to be between technologists and environmentalists -- let's say these are extremes. But they could be between, technologists and technologists. They are not usually called political factions; but there are within a technology, some people who are more conservative than others. You know there can be disagreements, especially about a new innovative project, whether it's going to work.

Schulz: What would be an example of that?

Petroski: Well there was for example in London in the middle of the 19th century, they were going to have a great exhibition, really what was to be the first World's Fair. And they needed a building to house it -- an enormous building because they were inviting people from all over the world to bring their products to display. And the only space that would hold such a building was Hyde Park.

There was first a battle over whether anything should be built in Hyde Park at all, so it was agreed that there would be a temporary building, something that would only be up for about a year. That was a political compromise. And then there was a question of whether you could tear down any trees, so there was really a technologist and environmentalist issue there. You know, there were also some people who were engineers who swore the thing would not work -- it would ether be too hot or the wind would blow it down and so forth.

So there has to be a certain resolve, which ultimately becomes a political resolve, that yes I believe in this; I believe it's going to work. And there have to be compromises and wise choices and then positioning. We see a similar thing with the space shuttle that just went off, I guess it was yesterday. There were all these stories about is it going to go or isn't it because there were still some obvious problems. But somebody basically bit the bullet and said well we can't put it off forever. If we really want to pursue this mission that we believe we have to go up and service this space station.

Schulz: I remember reading a book called Last Train to Paradise by Les Standiford. It's about Henry Flagler's project to build a railroad to Key West, Florida.

Petroski: Oh yeah I know that book.

Schulz: Standiford pointed out that Flagler was able to do this in his time; and yet if somebody wanted to propose this kind of project today, there would all sorts of obstacles to his accomplishing that.

Is your sense that there are more obstacles today to engineers trying to achieve these sorts of things, or there are fewer or that they are just different?

Petroski: I think there are probably more, because there are more projects proposed and also communications is quicker so dissemination of ideas and opposition is accelerated. But I think there always have been naysayers, let's put it that way. In the case of this Flagler example that you mentioned, I would suspect that some of the same people who would have opposed it when it was being proposed would be opposed today to tearing it down because it gives them access to the Keys. I would guess, not being totally familiar with the Keys only having been there once, that a lot of the people down there would identify themselves as liberals and environmentalists.

Schulz: You mentioned that there are more projects today. What are some of the proposed engineering projects today that you are particularly excited about?

Petroski: Well the rebuilding of the World Trade Center is certainly an interesting project and that one is admired in political difficulties as you know. There is a bridge that is proposed across the Messina Strait between Sicily and the mainland of Italy that would be the longest suspension bridge in the world. That is on the cusp now. If they get the funding, it should go ahead. It's the kind of the project that's been talked about for decades. Some projects are talked about for centuries, like the Channel Tunnel for example. That was on the books and it was actually even started in the 19th century, but that's a perfect example of political opposition. Other projects that excite me today -- mostly bridges because I think I follow bridges the most. You know, Pushing the Limits is about bridges.

Schulz: You are a "pontist."

Petroski: A pontist. Well, I don't call myself that. Hahaha.

Schulz: Right, but in the book you mentioned that.

Petroski: Yeah, others used that term. But bridge projects have always been among the most daring because what remains to be bridged is obviously by definition what hasn't been bridged, yet. So the next bridge is always the one that is the greater technological challenge. There is a proposal to build a bridge across the Bering Strait for example. I think it's been dubbed the peace bridge. It was conceived more in the Cold War to be a link of physical, and therefore a metaphorical link too, between Alaska and Siberia (between the West and the East). There is a proposal to build a bridge across the Strait of Gibraltar, so it would link Africa and Europe. These are pretty exciting projects, not only because of the technology, but precisely because of the politics. So politics is at the same time the major obstacle and on the other hand, it's part of the achievement to solve the political problem.

Schulz: What, in your view, are the two or three greatest engineering achievements in history and what accounts for their greatness?

Petroski: Oh gee, that's a tough question because I think it depends on context. In other words, what might have been a tremendous challenge at one stage is not at another stage. Back in the late 18-century for example, virtually all bridges were either stone or timber in construction. So in the 1770's, there was proposed an iron bridge -- something made of iron. This went against all tradition for one thing. And so to achieve that (and it was achieved in 1779 -- the first iron bridge), it was only 100 feet in span, but it was a remarkable achievement then. And now it's a trivial technological achievement. But it involved technology that was really pushing the limits, in that you were trying to cast larger pieces than had ever been cast before. So I would class that specifically, if you want me to name a particular thing. But projects like that are legion, so it's a class of projects that I would admire.

Schulz: That one is so much so because it marked a categorical break from what had come before.

Petroski: That's right. It's emblematic of the industrial revolution and all of that stuff. The steam engine would be another example. It's really of the same era, but what it did -- it really revolutionized the rest of the world. It lead to the railroad and it enabled mills and factories to move away from water sources of power and really locate anywhere where they would have a source of fuel to burn to generate steam.

The concept of powering something by steam was by no means new. Back in ancient times, there were examples of things running on steam power; but they were largely for amusement and not for practical purposes. So developing the steam engine was very, very significant. And then the railroad which came out of the steam engine. These things build on each other.

The railroad definitely would not have been able to exist without the steam engine. And then, it would not have been able to expand into territories that it did without iron bridges. So all of these things are really inter-related. The skyscraper is another tremendous achievement that I really admire. There, it was steel replacing iron that made that possible -- that made it possible to build high in an economical way.

Schulz: In your book, you titled one of the chapters "The Fall of Skyscrapers." You discussed 9/11 and the destruction of the Twin Towers. Is it your sense that concerns over terrorism have, in a sense, killed the skyscraper or the era of the skyscraper? And if it hasn't, why not?

Petroski: Well, I think I qualified it. In the West, I think it has for the time being. We see it in New York. There are some people who want to build as high as or higher than the World Trade Center, as if to thumb our noses at the terrorists. But there are other people that recognize that this is a very risky thing to do -- to tempt them to hit us again in the same place basically. And it's not at all clear that New York City needs all the square footage that would be another tall building at that site. Because after 9/11, a lot of the tall buildings were vacated. Basically, leases were not renewed and I think New York City still has a pretty high vacancy rate in office space. I don't see the figures coming out because I don't think New York wants to publicize them particularly.

Now tall buildings, however, are being built over in the Middle East and the Far East. They are going up like crazy. The tallest building until very recently was in Kuala Lampur, Malaysia. Who would have thought that 20 years ago? And now, the current tallest building is in Taiwan for example. And I think one is being built in one of the Middle East Countries.

Schulz: Dubai maybe?

Petroski: Dubai I think. I think that's going to be a tall building. Proposals that have been put forth in places like New York for the Freedom Tower or in Chicago where there was a proposal to build the tallest building in the world -- these are not making it, largely for economic reasons. You might term them also political reasons. The political and the economic actually get pretty intertwined there.

Schulz: I thought one of the most interesting chapters of your book comes towards the end, and you mentioned in it what's now a mostly forgotten book called Engineer's Dreams. Maybe you can give our readers a sense of what was so noteworthy about that book. You even mentioned that you had people ask you about it, they can't remember exactly what it about it. What was so extraordinary about that that book?

Petroski: Well I think that book was published in the 1950s and it described things that were not reality yet, but were dreams -- things like the Channel Tunnel, solar power, wind power; things that now we know have been achieved or are achievable to some degree or another. But I think then it was futurology almost. Of course the 1950s was also the time when we were fist going into space -- Sputnik occurred in 1957. So I think this was pretty exciting stuff. In fact, the guy who wrote it, Willey Ley, wrote a lot about space exploration. He was really tuned in to what really interested people. I think we all share in technological achievement and the wonder of it. They're proud that this is literally a human achievement -- it's just not the people in New York or Dubai that build the tallest building in the world; it's part of the whole human endeavor that is on trial there to do it and to get it right.

I think what also kept that book in the minds of the people over a period of roughly 50 years was because some of the things he described in there had not been achieved and were literally still dreams. Sometimes perhaps impractical by most standards, but nevertheless could be imagined. One thing, for example, that captured my attention was his proposal to drain the Mediterranean, not completely, but put a dam across the strait of Gibraltar and let the level of the Mediterranean sea sink a considerable amount, so that there would be more shoreline exposed. That would then provide more land for a very crowed Europe.

It's physically doable -- technologically doable. But is it the kind of thing that should be done? And I think he raises all sorts of questions like that.

Schulz: If you could put on your own personal imagination hat for a moment, what would be your engineer's dreams?

Petroski: I can't say that I have noodled on these things very deeply but one thing that comes immediately to mind for me is transportation systems. They are so frustrating when we know we have the technology to go fast and yet we don't go fast, either because of gridlock or an accident or weather (with regard to airports) or derailments (with the Metroliner between Washington and New York or the Acela train). Now these are things that seem almost to be ho hum technology in that they have been around and are so well established. But there is something about the social and environmental context in which they exist that is very, very frustrating.

And minimizing accidents and injuries and deaths by automobiles, for example, should be something that we could do and yet we don't seem to succeed. There are more people killed in cars every year than in airplanes by many factors of ten and yet we worry so much about airplane crashes and yet we don't about automobiles accidents. I think that's an example of where technology and the social sciences probably would be able to possibly work together and do something.

It's interesting: the whole idea is of combating terrorism technologically is another issue. We see the possibilities; London bombings recently and in the subway and on buses. New York for example has stepped up its security and is looking into and inspecting bags. There seems to be some opposition. People are voicing concern that this is an invasion, and yet we submit to this every time we go on a plane. The amount of modification of behavior that we've put up with to go on airplanes is enormous. Not only do we have to be prepared to have our bags looked at, but if we go to the airport with somebody, they can't go to the gate with us anymore. They can't meet us at the gate. It's just a revolution on how we have our interaction with the airplane. So I would think there should be great opportunities for cooperation between hard technology and the softer social sciences - figuring out ways to improve the situation and have people at the same time understand that it's really not a violation of privacy so much.

But you know what we are talking about -- how many people take the New York City subway everyday? Four million or five million. Even if these policemen are looking through your bag, they're not seeing anything if it's not a bomb. They are not that prurient. They've got a job to do. Your stuff is impersonal to them.

If you go to a library, it used to be more so than now, you have to open up your book bag and let it be gone through and people just accepted that. It shouldn't be such a threat to people's privacy. They do have the freedom of choice of not using it.

Schulz: To that end, is there anything specifically, say on the technology front, that you can think of that we already have, or that we are near to having that can be employed to help things out?

Petroski: Well, I am not in that field and I don't follow it directly, but I would actually hope that the latest technology is not accessible to someone like me who is not in the field because then it would be accessible to terrorists also. There should be an element of surprise. New technologies for detection should be able to be launched and take the terrorists by surprise.

Certainly, it's not going be long before they do pick up on it and circumvent it, because that seems to be the nature of technology. You introduce the new technology and somebody is going to develop something to get around it -- like when radar guns were first developed to catch speeders then speeders started incorporating radar detection devices.

Petroski: So this just naturally is going to happen. So I think if we are talking about terrorist detection devices, we should not be advertising them. It should be top secret stuff.

Schulz: One of the things that struck me, and maybe I am not thinking about this correctly, but it used to be the case that even 250 years ago, communication technology was basically only as fast as transportation technology. In other words, if you wanted to get a message from New York to London, you could put it on a boat and get it there. And so, as quickly as the fastest transportation at the time could get it there is as quickly as you could communicate there.

But in the last couple of hundred years, we have seen enormous gains in the speed of communications technology but I would suggest maybe not as rapid in the transportation sector. Clearly we have trains and automobiles and aircraft and whatnot, and yet you can get a message anywhere around the world instantaneously, and yet it still takes 18 hours to go from Washington to Tokyo. What I am wondering is, are there limits that can be overcome in the transportation realm in terms of getting people to and from places faster that you can think of?

Petroski: No, in fact we have actually retreated. The Concorde got us across the Atlantic much faster than anything today, but it was the question of coming back to economics and politics. It was not economical to do so and largely it was not economical because of the political opposition. The Concorde was not allowed to fly over land in most cases and create sonic booms, which are necessary if you are going to go faster than the speed of sound -- so the political restrictions (and I involve environmental issues too) are really what the limits are. So they are not technological surely. And I guess this does come back to what we started talking about.

Schulz: The 20th century was a pretty extraordinary century for the United States in terms of engineering feats. What countries today are the most exciting places today for engineering projects?

Petroski: Well I still think the United States is. I am not sure there is any country I can think of that has the breadth of technological fecundity, if you will, that the United States does. You know Japan specializes in certain things; I am not sure how original a lot of China's technological development is right now.

It depends on how you measure these things. If you look at science -- Nobel Prizes. I think still the United States has a disproportionate number of Nobel Prize winners. I read an article not long ago that Japan is scratching its head wondering why they don't have Nobel Prize winners.

And then what would be the technological measures? Well that becomes a little tougher because you have to figure out what to measure and different technologies are measured in different ways. But, I think with a lot of the microelectronics, the United States is still pretty much the place to look to. Now we are not talking about manufacturing, but we are talking about development of new technologies. So I think we have to think differently. We have to separate technology into development and manufacturing let's say.

Then of course then there is the complication of stuff being "offshored," as they say. Which further complicates it. We hear a lot about China and India, but so many of the people that are in high technological positions in China and India were actually educated in the United States. Now, it's going to be interesting to see what happens over the coming decades where increasingly those countries have their own educational system that's getting increasingly mature.

There is, especially in the wake of 9/11, increasing problems with foreigners studying in this country (especially the sciences and the technology fields). So it appears to be a changing climate, but how it's going to play out is not totally clear to me.

Schulz: You've mentioned that the engineering feats that you probably know most about and that you focused a lot on this book are bridges. Do you have a personal favorite of all the ones that you've either visited or studied or know about? And if so, what is it and why?

Petroski: Well I have been asked about a lot, I usually try to avoid it.

Schulz: Sorry.

Petroski: But, I will mention... The Brooklyn Bridge for example is almost everybody's favorite. It's an icon, but it's interesting even beyond its iconic status. If you know its history and you know the technological environment in which it was designed and built, it really was innovative in many, many ways and extremely influential. Suspension bridges were -- well really still are -- based on principles that were introduced in the Brooklyn Bridge. It is also interesting that the bridge is over a 100 years old; it was completed in 1883 and it still looks modern in many ways and not copied. Nothing has really come close to it in my opinion.

Then on the other side of the country is the Golden Gate Bridge, which is also an iconic structure. It's so closely associated with San Francisco that's it's hard to walk into a souvenir shop and find something that doesn't have the Golden Gate Bridge on it.

Schulz: Right.

Petroski: And I like the Golden Gate, less for its technology. When completed, it was the longest bridge in the world; and therefore, you could say it was a great technological achievement because it was longer than anything else. But that's not what attracts me to it. What attracts me to it is its lines, its beauty. It really is a thing of beauty. And it's not just its colors, it's the silhouette -- the proportions of it are so wonderful. And, again knowing it's story (and to tell its story fully takes a whole book), but knowing its story elevates it, at least in my mind, so that I see a lot of the things that do make it a favorite of mine, if you will.

Even though you could also criticize it. You could criticize it; you could criticize the Brooklyn Bridge. In certain ways they were obsolete once they were built. But that's getting a little bit esoteric for our discussion.

Schulz: Is there anything that's underrated in your view or that should get more attention? I mean, obviously those are two iconic structures, but is there anything that people might not know about that's really extraordinary to you?

Petroski: Common things. I have written about the paper clip for example. I think that's also iconic in a way, but I think it is under-appreciated. Little things like that paper clips, pencils...

Schulz: Right, you wrote a whole book on the pencil.

Petroski: If you know their story, you know the story of all technology almost because they involved invention; they involved economic battles; they involved marketing battles; they involved evolution; they involved change. They involved almost endless attempts to improve upon them. And somehow, everybody who tries to improve upon these things is frustrated.

The classic Gem paper clip that was invented over a hundred years ago by an anonymous person -- everybody's tried to improve on it; and it's still the one that survived, the one that endures. So, things like that I really admire. I like to think about. They are full of insights, knowing their story.

Schulz: Terrific. Well, thanks so much for taking the time to talk to us.

Petroski: You're welcome.

Click here to listen to an excerpt from this interview.
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