2018 Structural Engineering Research Fellowship
The Poetry of Structures

The relationship between structural engineering and architecture as distinct yet complementary disciplines and the more general debate between engineering and aesthetics have become somewhat common subjects on which plenty of critics, architects, and even engineers have given their views. What are the differences between good engineering and great engineering? What are the ideals structural engineers should be striving for? This introduction does not intend to bring definitive answers to those questions; however, it does provide a personal appreciation of what is at stake, in a world where the global population is increasingly more urban and where resources are decreasing at a fast pace.

My personal conviction is that at their best, structural engineers are poets, whether consciously or not. Arguably, there can’t be two more opposite disciplines than structural engineering and poetry: buildings and bridges are immediately useful for the community, while poems are considered optional reads—at best. An Engineer’s first constraint is efficiency, while a poet’s first objective is aesthetics. Steel, concrete, glass, and timber can be touched, while words are abstract. For most cases—for most buildings and bridges, and also for most poems—those differences make sense. Were you to have a discussion with a structural engineer or with a poet, you would immediately understand them. However, miracles sometimes do happen where the two disciplines, how far they generally stand from one another, merge to produce not good but great works of engineering and poetry. This research, generously funded by the SOM Foundation, obviously focuses on structural engineering—how great pieces of structural engineering work as poems. However, the reverse statement could also be true: the structure of a poem is very important, and great poems would not be great without a solid structure. But that would be the subject for a literature article, which is not the scope of this work.

Dissecting structures and poems, an easy statement is to say that structural engineers work with materials—steel, concrete, timber, and glass for the most part—while poets “build” poems with words. A second thought on what words really are makes this comparison a little trickier: should we mention the ink that the poet himself used when originally writing the poem? Or should we instead consider the ink used for printing the book containing the poem? In today’s digital world, such questions on the materiality of words are even more difficult, while for buildings or bridges, physical contact is always possible. In any case, it is still acceptable to say that structural materials and words are respectively the base elements for the two disciplines.

The level above those base elements would be the beam, slab, or column for the structural engineer and the sentence for the poet. Again, when making those analogies, one should keep in mind the essential differences as well: beams, slabs, and columns are mainly materials given a certain shape, while sentences are words put together. Poets do not give a shape to words, or very rarely; however this does sometimes happen, for example for tags written on walls—by the way a surprising example where structural elements and sentences come together. To be perfectly correct, structural elements are most often also the result of several pieces put together—via welds or splices, for example—but in general those links are purposely concealed, as what counts in finished structural elements is really the thickness or aspect ratio of the overall beam, slab, or column, and not the individual pieces comprising that element.

Finally, the third and final level is the structure—for engineers—and the poem—for poets. The structural elements work together to provide stiffness, strength, and stability. Similarly, the different sentences when read together provide the poem with a general meaning and aesthetics—although there is no denying that some poems may be hard to understand for the majority of us, if not in some rare cases for everyone but the poet himself. Individually, the meaning and aesthetics of the sentences have little to do with the ones of the overall poem. Likewise, the stiffness, strength, and stability of the structural elements have little to do with the ones of the resulting structure—this can be fairly quickly seen by looking say at a simple portal frame with stocky columns and a thin slab. Again, what can be observed here is a general pattern, although stiffness, strength, and stability are evidently different concepts from meaning and aesthetics—which is why for most cases, structural engineering and poetry are still very distinct disciplines. Up to here, quite interestingly, the reasoning itself blends engineering and poetry: reducing poems to a mere assembly of sentences themselves made of words is an analogy with the built world, while the act of comparing distinct objects—here, buildings and bridges to poems—is in a sense poetic itself, as comparisons and metaphors are essential figures for poets. The analogy presented above therefore makes sense up to a certain point, but as with all analogies it is not enough to truly understand how structural engineering turns into structural art.

When he coined that expression “structural art” in his famous book, The Tower and the Bridge, David Billington genuinely meant to bring structural engineering at its best to the same level as the other arts, such as painting, sculpture, and even architecture. [1] That is still quite a bold statement today, as aesthetics holds a limited space in the industry—aesthetics is far from being the primary criterion in tender analyses—and structural engineering education—both undergraduate and graduate classes teach the design and analysis of conventional structures and give little space to experimentation. Anyway, progress has been made in recent years, and figures such as Santiago Calatrava—however controversial he may be—Félix Candela, Eladio Dieste, Heinz Isler, Robert Maillart, Christian Menn, Marc Mimram, Sergio Musmeci, Pier Luigi Nervi, Michel Virlogeux, and others are now widely recognized as structural artists, which is not quite the same as architects—although again, Calatrava is also an architect himself. As mentioned in the introductory paragraph of this report, comparing structural engineering and architecture is not the point of this work. However, when quoting Billington it is nearly impossible to completely evade the topic. Those who know the subject well enough know that although efficiency and aesthetics are universal concepts, the debate depends on where it is conducted: in Europe, it is widely accepted that engineering and architecture separated after the industrial revolution due to the specialization required in the different fields—an engineer could not do it all by himself anymore—whereas in countries like Japan, architecture is still taught to all structural engineering students. They “specialize” in structural engineering only afterward and therefore have a much more advanced understanding of architecture than their European or American counterparts. Still, Billington’s concept of “structural art” and the three objectives of “efficiency, economy, and elegance” as its main criteria are not quite enough to compare structural engineering and poetry. Poetry is an art, true, but a special art of its own.

Going one step further is mentioning the slightly different concepts of experimentation, authenticity, and details. A great bridge, for example, is often the result of experimentation with structural materials put to their limits. This naturally holds true for megastructures—see for example the Akashi Bridge in Japan, which holds the longest bridge span of all types at 1,990 meters—and smaller structures—the Zorlu Apple Store in Turkey has its lantern entirely made of structural glass. Where there is experimentation, there is also a certain amount of risk taken; as the design has never been done before, there is a higher level of uncertainty on the stiffness, strength, stability, cost, constructability of the structure, as well as on the client’s and public satisfactions. As global warming is putting the whole of mankind in danger, there has been an increasing number of projects made of sustainable structural materials in the recent years: the Grandview Aquatic Center in Surrey near Vancouver, Canada has the world’s longest timber roof span, which happens to be the very local, relatively low-cost material. Similarly, great poems always innovate in one way or another, whether by the rhythm, the metaphors, or the style—see Stéphane Mallarmé’s work on visual poetry, for example. Back to engineering, one could cite many other types of experiments, including the wind tunnel tests performed for high-rise towers to reduce vortex-shedding effects and base moments—for example, wind tunnel tests conducted during the design of the Shanghai Tower resulted in a shape optimization leading to a 24 percent reduction in structural material compared to more conventional shapes of the same height.

Second on the list, authenticity is another common point between great structures and great poems. Projects are inscribed within a natural and cultural environment and benefit greatly from the use of local materials and/or craftsmanship. On the other hand, an “unauthentic” project would pay no attention to those local resources. For example, the Feng Hua Bridge in Tianjin in China, by Marc Mimram, clearly illustrates this concept: it consists of arches braced with steel reinforced polyester fiberglass plates, shaped like petals and produced locally. Having this unique type of bracing in a different region would also be good—eventually, both bridges would look identical—but not great—the design and fabrication would not take advantage of the local context. Authenticity applies to many other industries: for example, in the world of high-rise buildings and museums a reference to local contexts is almost always emphasized—often, a point is made and the resulting work makes sense, is authentic; sometimes though, the argument is shallow and seems only driven by communication considerations. Taipei 101, with its bamboo or inverted pagodas look, is an illustration of a “universal” type core/megacolumns structural system blended with local references. In poetry, the same applies inasmuch as the poem is by nature an expression of the author’s subjectivity—it is based on the author’s direct observations or interpretations. The aesthetic potential of the stylistic figures is genuinely assessed by the poet himself, and the poem’s power stems from the fact that it deals with life or the world directly—there are no third parties involved between the poet and his text, contrary to other literary styles, for example novels, where editors play a significant role in commenting, cutting, or adding on the text submitted to them by the novelist.

Finally, the care for details is certainly shared by great structural engineers and poets alike. In structural engineering, details allow for constructability, thermal expansion, and contraction, ductility during earthquakes, to name a few. In poetry, details are fundamental, whether in the rhymes required in classic poetry or in the choice of words—as most words carry more than one meaning. The three criteria of experimentation, authenticity, and details, by providing further analogies between structures and poems, are meant to provide a different perspective on Billington’s own criteria of “efficiency, economy, and elegance,” which themselves echo Vitruvius’s criteria of durability, convenience, and beauty for good architecture. However, to go beyond analogies and their inherent weaknesses, it is necessary to turn to philosophy and, in particular, to phenomenology.

In a famous essay, analyzing Friedrich Hölderlin’s poetry, Martin Heidegger wrote that “poetry is a measuring” of the space “between the earth and the sky,” referred to as the “Dimension.” [2] That intermediate space defines our human condition, by nature mortal. According to Heidegger, poets are therefore the most serious people on Earth—the ones who address our most essential interrogations, contrary to a popular belief that considers them as deviant or useless. There is no more important or difficult question than human nature, and poets are precisely the ones who “measure” that space where we dwell. However, and this is where the magic happens, Heidegger shows that dwelling and building are essentially two sides of the same coin—in German, the verb bauen has those two meanings—and therefore concludes that “authentic building occurs so far as there are poets.” This statement justifies the criterion on the authenticity mentioned in a previous paragraph. But before all, it closes the loop between structural engineering and poetry. In other words, great structural engineers are poets in that they build structures that reflect on our human condition and its “dwelling” above the earth and under the sky, mortal by nature but capable of the most incredible achievements. Since being a poet is the act of “measuring” that space in between, great structural engineers are themselves poets when they produce such reflective structures. If the comparison has not been made before, it is because that poetic aspect of structural engineering is either overlooked or unconscious; however, it is no less real. There is no more convincing word than the “measuring” adjective: every day, and all day long, structural engineers measure loads, deflections, stresses, and so on. Those measurements, when allied with experimentation on materials, authenticity, and great details, produce masterpieces in that they give a scale of our passage on Earth. Looking for such scales and expressions is precisely the work of a poet, through words.

The Teshima Art Museum in Japan is one of those examples of a “Heideggerian” poetic structure: located on a hill of a small island away from the big cities, in that intermediate space above the earth and under the sky, it challenges our stressful, urban life and redefines a more direct relationship to nature. Its structure is minimal in that it consists of a free-form concrete shell with a central opening, and nothing else. The only works of art displayed are the silence and the fluidity of the water drops flowing down the slightly sloped base surface, which is a perfectly smooth concrete slab probably covered with a hydrophobic agent to emphasize that movement. Experimentation is there with the free-form shell finding optimization algorithms derived by Mutsuro Sasaki: starting from an initial shape, the shell is optimized until a state of minimal potential energy is reached. [3] Authenticity is also very much verified: minimal structures and perfect concrete finishes, typical of the Japanese people—the long Japanese tradition in timber architecture has converted into a brilliant formwork industry, which explains in part the success of Japanese architects using concrete such as Tadao Ando, Toyo Ito, and others. The attention to detail can’t be denied either: the water drops seem to be coming from the opening in the roof but actually come from tiny holes in the base slab—accordingly, not a structural detail, although the most evident one on this project.

Structural engineers are not generally fond of phenomenology or poetry; therefore, it may be useful to hear a few of them. The famous American poet Williams Carlos Williams wrote the following: “Prose may carry a load of ill-defined matter like a ship. But poetry is a machine which drives it, pruned to perfect economy.” Here, the author refers to the specificity of poetry being short in length compared to novels. Because they say a lot in a few words, poems are efficient. The “economy” directly recalls one of Billington’s three criteria. Another famous poet, Octavio Paz from Mexico, wrote the following paradox regarding poetry: “result of chance, fruit of calculation.” [4] Structural engineers’ primary job is to conduct calculations of all types for the stability, strength, and constructability of a structure, yet at the same time, despite all the in-depth calculations and planning, there is an irreducible part of chance in all the pieces coming together on a complex structure. That is because those calculations aim at reducing to a minimum the risk of collapse or failure. However, and this is inherent to the field of statistics, it is impossible to assess that a structure has absolutely no chance of collapsing whatsoever. As a matter of fact, the load factors that are used every day for design are based on structural reliability calculations; for example, the higher load factor for live loads indicates a lower reliability index on their magnitude. When a certain design criterion is verified on a spreadsheet, it only means that under standard Gauss distributions for the material properties and load magnitudes, this criterion will be met. Of course, there are a lot of real-world situations where chance seems to be a factor despite all the calculations: when installing the closing span of a prestressed concrete bridge erected using the balanced cantilever method, hoping for a smooth alignment; when casting the deck of a severely curved steel/concrete composite bridge, hoping for optimal cross slopes; when walking on a pedestrian hanging bridge in the mountains, hoping for sufficient cable strength; and so on. This is because structural engineers know the limits of calculations and the risk of errors, which reflects again on our human condition and its imperfection. In poetry, the same applies. Despite all their efforts, inspiration—and therefore chance—plays a major role in the success of the writing process.

All in all, this idea of associating structural engineering with poetry is not so new. In Ancient Greece, arts were well defined: music, sculpture, architecture, poetry, etc. Some contemporary philosophers, however, convey the idea that the boundaries between the different arts have become more vague than what they look. For example, when studying the visual poetry of Mallarmé, Jacques Rancière asks the following question: “How to conceptualize this space which renders the textual and the plastic identical?” [5] This questions our traditional views on space: it is not only a mere surface of inscription, but rather an instance of “shared meaning,” where different languages converge. Poetry is a language, which must be learned to be understood. In the same way, structural engineering is itself a language, which obviously needs a different type of learning. When there is a fruitful dialog between the two languages, the boundary between them becomes not so obvious. This applies to the visual poetry of Mallarmé—and by extension, to the surrealists—and can for example be seen in a famous poem by Guillaume Apollinaire called “Calligram,” where the poem’s shape—or structure—is the profile of the Eiffel Tower. [6]

Being from Paris, France, I could of course have selected the Eiffel Tower in my itinerary, as well as a few bridges over the Seine River—who does not appreciate a night walk over the Bir Hakeim Bridge. I know those places well, and they may have unconsciously played a role in my becoming a structural engineer. Instead of that, I picked some places located further away, to take advantage of the generosity of the SOM Foundation, to which I again wish to express my deepest gratitude. One of those places turned out to be even too remote: the Mapungubwe Interpretation Center in South Africa, a beautiful masonry construction near the border with Zimbabwe, required much more time and effort than I initially thought, and therefore had to be unfortunately dismissed. Owing to the essence of civil engineering projects, another site turned out to be in maintenance, the Iron Bridge in England, the first metal bridge in the world. The bridge was totally covered with extensive scaffolding, making photographs irrelevant to appreciate its aesthetics. Even worse, the Diamond Island Community Center in Ho Chi Minh City had been already dismantled by the time I visited Vietnam. This beautiful bamboo dome united the virtues of experimentation, authenticity, and details presented above. Unfortunately, tennis courts and other facilities have now replaced it, providing luxury living to local residents in a chic neighborhood of the city. Finally, and this is because my wife was in her seventh month of pregnancy at that time, I took a shortcut on my final trip, leaving a couple sites for the future: I did not visit the Bridge House in Mar del Plata, Argentina, a reinforced concrete private house designed by Amancio Williams, musician and precursor of modern architecture in Latin America. However, I did compensate that shortcoming by visiting the Curutchet House in La Plata, the only built project by Le Corbusier in South America, actually implemented by Williams himself. I also decided to leave the Te Rewa Rewa footbridge in New Zealand for another time. I hope that the Foundation will forgive me for leaving those couple sites. There are still thirty-five projects presented in the main body of this report, which cover twenty-four countries and five continents. Those projects represent a small fraction of all the sites I actually visited, but I will not present them all in this report for the sake of keeping a reasonable document length.

Many of the buildings I covered are located in capital cities, or at least in large cities: Vancouver, San Diego, Chicago, New York, Santiago, Edinburgh, Eindhoven, Gelsenkirchen, Istanbul, Baku, Doha, Abu Dhabi, Tokyo, Sendai, Shanghai, Tianjin, Taipei, Ho Chi Minh City, Sydney. This makes the visiting of those sites relatively easy. For a few other projects, however, accessing the sites—mostly, bridges—proved much more difficult. The palm goes to the Hardanger Bridge in Norway, which required nearly 200 kilometers of cycling in one day from Bergen. The effort may be one of the reasons why I consider it as one of the most beautiful bridges worldwide. I also hiked a good couple hours in the Swiss Alps to reach the Charles Kuonen Suspension Bridge, took a couple trains then a ferry to access the Teshima Art Museum in Japan, fought through an extensive immigration screening at Tianjin International Airport before being able to get close to the Feng Hua Bridge, etc. The experience was always fantastic despite the difficulties.

The final report goes over individual descriptions of the projects I initially selected, plus a few others that I added to compensate for the ones I could not cover. In particular, I felt I had to go pay a visit to the Akashi Bridge, which holds the longest span in the world at 1,990 meters. Although not on the initial list, this visit proved one of the most inspiring on the entire journey. For each project, I go over some facts first—structural engineers like numbers and poetry is a “measuring,” as mentioned earlier—before expressing my personal appreciation of their aesthetics and engineering. Because pictures speak a thousand words, I kept the texts short. My goal is that for those who can’t go to these sites, the text and pictures will provide a good description. If they can inspire at least one young reader to engage in a career in structural engineering, then I will be really happy.

Photography is an excellent way to illustrate the poetry of structures. This is because for poems, bridges, buildings, and photographs altogether, geometry is the key. Whether for the straight lines of the 432 Park Avenue tower in New York City or for the curves of the Bosjes Chapel near Cape Town, the truth is in the geometry. Architectural photography itself is an art, and I have modestly tried to follow the footsteps of the great architecture photographer Philip Jodidio.

For bridges, the structure is exposed and the aesthetics therefore stems from it directly. The Akashi Bridge in Japan, the Hardanger Bridge in Norway, the Queensferry Crossing in Scotland, the Musmeci Bridge in Italy and the Dandeung Bridge in Korea all have expressive structures. Their aesthetics, however, are not unique. The Akashi Bridge stands out by its massiveness, the Hardanger Bridge by its slenderness, the Queensferry Crossing by its continuity, the Musmeci Bridge by its organic aspect and the Dandeung Bridge by its point of focus—its single pylon.

For buildings, the structure may be exposed. This usually happens when the engineering involved is avant-garde for its time. The Sydney Opera House, for its shell type structure, the Qatar National Convention Center, for its free-form, tree-like structure, and the Teshima Art Museum, for its geometry, all represent engineering breakthroughs. At the same time, they show how the work on shell structures has evolved, from hand calculations to form-finding optimization algorithms. They illustrate the general movement toward parametric modeling and design.

Some buildings marry in a remarkable way the structure and the material: the Apple Zorlu in Istanbul has monolithic structural glass walls, while the Library of a Poet near Tokyo has its structure entirely made of paper tubes. Those are special projects and in general, such a “simplicity” is impossible.

For the other buildings however, the structure is concealed behind the envelope. This is the case of the Busan Cinema Center in Korea and the Heydar Aliyev Center in Baku, for example. For these type of projects, the structure is fundamental but the aesthetics lie in other aspects of the architecture. Engineers must admit here that the structure is just one part of the architecture. And architects, that their work would be impossible without the collaboration with structural engineers. That ambiguity between structure and architecture, due to the fact that the structure is sometimes hidden, sometimes not, can be paralleled with the one observed in poetry, where words have different meanings and the poem’s interpretation left to the reader. For the nineteenth-century philosopher and poet Giacomo Leopardi, beauty lies precisely in the vague and the indefinite: “The more vague and imprecise language is, the more poetic it becomes.” [7] The subtlety lies in that this aesthetics of the vague is paradoxically achieved by a careful attention to details. This is why Italo Calvino stated that “the poet of vagueness can only be the poet of precision.” [8] The free-form envelopes that are becoming increasingly common in contemporary architecture do convey that aesthetics of the vague; however, they are based on very precise calculations and care of details.

David Billington had a point in writing that efficiency, economy, and elegance are the criteria of the new art of structural engineering. My only comment would be that those ideals hold true within what the architect envisions—the architect may have other purposes that are not compatible at first with a minimal structure. Not surprisingly, in countries like Japan, where the collaboration between structural engineers and architects such as Toyo Ito and Mutsuro Sasaki is quite common, this results in poetic structures, such as the Sendai Mediatheque. SOM is one of those few firms where architects and engineers work together, and this can only be beneficial to the quality of the projects. Regarding Billington’s criteria, it is interesting to read Jacques Rancière, who when comparing Mallarmé and Behrens—the German architect—wrote the following: “Poetic labor to Mallarmé is a labor of simplification. Like engineers, he dreams of an alphabet of essential forms, taken from the ordinary forms of nature and social world.” [9] Today, as sustainable development has become critical, some architects and engineers have a similar dream: an “alphabet” of prefabricated timber shapes and profiles to design the sustainable skyscrapers of the future.

In any case, it is wrong to systematically oppose the arts of structural engineering and poetry. In his autobiography, Peter Rice from Ireland discusses a few of the most interesting projects he worked on, including the Centre Pompidou with Renzo Piano in Paris and the Sydney Opera with ARUP. [10] The accuracy of the technical details mentioned by Rice is undeniable. However, this does not prevent him from including some of his own poems in the book. After all, it may be that words and equations talk about the same thing.

There is no better way to experience works of structural poetry than traveling, and I am sincerely grateful to the SOM Foundation. Structure, architecture, poetry, however you name it, were the scope of this research. But because all those projects are inscribed in cultural contexts, it is important to learn about the history of the places and the people where they were built. The experience learned through all those travels over the past eighteen months therefore goes further than just structural engineering, and I wish to thank again all the people I met along the way.

Notes

[1] David Billington, The Tower and the Bridge: The New Art of Structural Engineering, (Princeton, NJ: Princeton University Press, Revised Edition, 1985).

[2] Martin Heidegger, Poetry, Language, Thought, (New York, NY: Harper and Row, 1971).

[3] Mutsuro Sasaki, Toyo Ito, Arata Isozaki, Morphogenesis of Flux Structure, AA Publications, London, UK, 2007.

[4] Octavio Paz, The Bow and the Lyre, (Austin, TX: University of Texas Press, 2009).

[5] Jacques Rancière, The Future of The Image, (Brooklyn, NY: Verso Books, 2008).

[6] Guillaume Apollinaire, Calligrammes: Poems of Peace and War, 1913-1916, (University of California Press, 2004 (first published 1918)).

[7] Giacomo Leopardi, Zibaldone, (New York, NY: Straus and Giroux, 2005).

[8] Italo Calvino, Six Memos for the Next Millennium, New York, NY: Vintage, 1993).

[9] Jacques Rancière, The Future of The Image, (Brooklyn, NY: Verso Books, 2008).

[10] Peter Rice, An Engineer Imagines, (London: Ellipsis, 1998).

Canada and the United States

Argentina, Australia, Brazil, Chile, and South Africa

Azerbaijan, Germany, Italy, the Netherlands, Norway, Portugal, Qatar, Scotland, Spain, Switzerland, Turkey, and United Arab Emirates

China, Japan, and South Korea