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Engineering for the Ecological Age: Lessons from History

John Ochsendorf: May 1, 2009; Running Time: 1:24:16

About the Lecture

About the Lecture

John Ochsendorf, a structural engineer, “fell in love with archaeology” during college. His senior thesis at Cornell involved a 600-year-old Incan suspension bridge made entirely out of grass. Ochsendorf learned that this apparently primitive structure owed its astonishing longevity to regular rebuilds by the locals (during a community festival), and the use of renewable, biodegradable resources. While Cornell’s engineering faculty couldn’t see the point of this research -- “grass bridges over highway overpasses”? -- Ochsendorf realized that historical structures held important lessons for modern building technology.

The grass bridge raised several problems that now consume Ochsendorf’s academic and professional life. First, how to consider the whole life of a product when designing it, of particular import since “the 21st century is going to be a wild ride in terms of natural resources,” says Ochsendorf. Some building costs increase over time, consuming material and labor while deteriorating (nb: New York’s 1903 Williamsburg Bridge, with $1 billion in repairs, and still unsafe at any speed).

Ochsendorf suggests alternatives: making permanent structures with high quality construction and reusable materials (such as Roman stone arch bridges); very temporary structures, such as the grass bridge, or a Japanese pavilion made out of recycleable paper; or modular structures designed to change over time. Ochsendorf created “a medieval building for the 21st century,” a sustainable home made out of waste clay tiles, rammed earth from local chalk, and a heavy green roof on which sheep graze.

Ochsendorf also studies the integrity of existing historical structures: how to guarantee the safety of a medieval cathedral, or a 19th-century train station. The Pantheon’s stood for 2000 years, a brittle structure that inevitably develops cracks. Engineers today can’t say for sure “if something will fall down.” Ochsendorf is creating engineering tools to vouch for the masonry, steel and concrete holding up both historical treasures and more commonplace infrastructure. He is also working on high tech tools so engineers can examine building designs before construction to ensure “safe results,” and to create structures that will consume less energy and emit fewer greenhouse gases during their lifetimes. As composers know Mozart, and philosophers know the works of Plato, concludes Ochsendorf, the next generation of engineers must review the works of their forebears, if they’re to maintain existing infrastructure, and create better designs for the future.

Lecture Details

Location: Bartos Theater

“The 21st century is going to be a wild ride in terms of natural resources. We need to rethink the ways we’re using and consuming resources, and the way we meet our needs and live the affluent lifestyles we’re accustomed to while dealing with climate change, when carbon emissions reach levels unseen for a few hundred thousand years.”

John Ochsendorf

About the Speaker

John Ochsendorf

Associate Professor, Department of Architecture, MIT
2008 MacArthur Fellow

John Ochsendorf is a structural engineer and architectural historian who works to preserve historic structures and to reinterpret ancient technologies for contemporary use. Ochsendorf has studied a variety of alternative engineering traditions, including hand-woven, fiber suspension bridges of the Inca Empire. He has also investigated suspension and cable-stayed bridges in Japan. More recently, Ochsendorf has explored the structural safety of such historic monuments as French and Spanish Romanesque churches.

Ochsendorf received a B.Sc. (1996) from Cornell University, an M.Sc. (1998) from Princeton University, and a Ph.D. (2002) from Cambridge University. He received the National Endowment for the Arts Rome Prize for 2007-2008, and was a Fulbright Scholar at the Escuela Técnica Superior de Arquitectura, Madrid, Spain.