What I Learned Building Bridges

What I Learned Building BridgesA Story From the Trenches About Creativity in Engineering

For as long as people have been building things, there have been, more or less formally, engineers. Over time, as the understanding of materials and physics became refined, the popular conception of engineers has led to the field’s classification as a technical, rather than a creative discipline. This classification is not necessarily incorrect as much as it is misleading. Engineering, be it of the structural, mechanical or even software flavor, is, in its purest form, as much a creative exercise as it is a mathematical exercise. Engineering, while dependent on the sciences, is not in itself a science. It is creation under constraint: the open-ended application of the basic, natural rules of a system to build something that does not arise naturally.

A popular misconception is that an artist is constrained only by his or her imagination. In reality, all artists, all creators, from writers to painters, are in at least some form constrained by their medium. The greatest creators become great by finding ways of stretching the possibilities of their medium, but a book or a painting, no matter how great, will always be defined by words or pigments. The same goes for engineering. Engineers work in a medium as well, defined differently by field, but ultimately just as constraining. A structure or machine will always be constrained by the materials (and the budget) used to build it. A piece of software will always be constrained by the limits of the computers it is written to utilize (a great example of this is the programmer’s need for memory economy which led to the use of two digit year dates, which later had to be corrected at the turn of the millennium, when the extra bytes were easier to come by).

My expertise is in bridges, and a great deal of bridge engineering is constrained by material and budgetary limits. For example, a tree across a creek is a good bridge for foot traffic, and its cheap and easy to build, but the material is weak if you want to drive a truck over the creek. On the other hand, a solid block of steel can carry anything across a creek, but to use so much steel would be prohibitively expensive. The solution is a structure which, while more complex, uses the materials available in a more optimal fashion. Bridge engineering is about balancing the fallen tree with the steel block. Every decision an engineer makes is about economy; economy of force, and economy of material. A modern day bridge uses each of its materials where they are most effective and even goes a step further, removing material where it is not needed. Take a look at that bridge in the header — every piece of steel you see is the exact right size in the exact right place, nothing extra, nothing missing. Yet the bridge you see above, while an economical and safe solution to the problem of crossing a river, is not the only economical and safe solution to that particular problem.

This is where creativity comes in, and the need to throw out the stodgy image of the engineer as a mere technical bookkeeper. If engineering was just an exercise in mathematics, there would be a finite set of solutions to any given engineering problem. Nothing could be further from the truth. The potential configurations of a Mississippi River bridge crossing are nearly infinite, encompassing a staggering variety of materials, structural forms and costs. The right answer is not defined by what is possible, but what is right for that particular client’s application, and there is no fuzzier word, no word open to more interpretation than “right”.

Bridges are great examples of the fuzziness of the “right” solution. When cost is a concern, solutions tend to look alike, use familiar materials and time tested configurations. But frequently a client looks for more from a bridge; they want a signature bridge, an addition to the skyline and are willing to pay for it (Google the new Oakland Bay Bridge). These bridges fundamentally perform the same function, but take a vastly different form due to the exchange of the “economy constraint” for the “signature constraint”. There are dozens of other constraints too, from soils to ship traffic that have to be considered when designing a bridge.

In the end the product of an engineer is by definition always what the client was looking for. It is a tailor made solution to the client’s particular problem. A computer can design a bridge, sure, but computers have yet to master the fuzzy areas of optimization that most engineers rely on to successfully create an implementable solution for their client. So next time you think of an engineer, throw out the notion that he or she just crunches numbers all day. Real engineers are the original creators, bending constraints to make what was once impossible a reality, using nothing but the extant tools available out in the real world. And from that world, the engineer creates a new one.

This article first appeared on Medium and has been republished here with the writers permission. You can read more of Jeremy’s articles on his blog.

Did you find this helpful? Subscribe to our newsletter

Jeremy Martin is a civil engineer and a writer. You can read more of Jeremy's articles on his blog.

Suggested Career Channels

Suggested Articles