John Ochsendorf wants to tear down Rome’s iconic Pantheon. He wants to pull apart its 2,000-year-old walls until its gorgeous dome collapses. Destroying it, he believes, is the best way to preserve it.
But the Pantheon that Ochsendorf, a professor of engineering and architecture at the Massachusetts Institute of Technology, has in mind to destroy is less than 20 inches high, and it’s made of 492 3-D-printed blocks. It’s designed from laser scans of the real building. A gaggle of MIT engineering students will place it on a table with a sliding base and pull the walls apart, then put it back together and tilt it until it crumbles.
It’s hard to see how razing a doll-sized Roman monument will help protect the real thing. But Ochsendorf, whose easy smile and self-effacing humor belie confidence and determination, has a serious goal: to prove that historical structures like the Pantheon are more stable than we give them credit for. “By every measure of success of a building—from an architectural, from an artistic, and from an engineering standpoint—I would argue that the Pantheon is the greatest that was ever built,” Ochsendorf says. “There’s no greater definition of success for a building than it’s been standing for 20 centuries.”
It also represents a masterwork of engineering and a repository of ancient technical knowledge—the structural equivalent of the Mona Lisa. Ochsendorf is working to halt what he sees as unnecessary interventions in historical buildings, in which engineers try to fix cracked or slumping walls with steel bars and supports. “We see a crack in a structure and we do a major intervention, but that’s akin to dipping the Mona Lisa in epoxy because one section of the painting has faded a bit,” he says.
Some interventions, designed to keep today’s tourists safe, might deteriorate in a few decades and damage long-lived monuments for future generations. But they may also be unnecessary. Many interventions arise, Ochsendorf believes, from a fundamental misunderstanding of how buildings like these behave.
“Too often, we’re trying to make old structures conform to theories we learned for steel and concrete,” he says. Those materials remain strong under immense stresses in modern buildings. But buildings like the Pantheon “stand because of their geometry,” he says, “and the way builders conceived them was really through their geometry.” Cracks and deformations, he argues, are not necessarily flaws; they’re often a sign that a building adapted to a sinking foundation centuries ago and found a new conformation. “We should conserve the great works of construction for future generations, and that means understanding what the original builders intended, and trying to be faithful to their intent.”
Ochsendorf, though, is more than a preservationist. His work, influenced by leading thinkers in structural theory before him, indicts the short-sightedness of today’s engineers as it underscores the engineering wisdom of the past. “We have this notion that we’re at the pinnacle of all time,” Ochsendorf says. It’s not that he thinks engineers should create new Pantheons, any more than contemporary poets should write Shakespearean sonnets. But he does say that studying masterworks makes better writers, artists, architects, and musicians. “I personally believe that by studying the greatest works of engineering of the past, we can produce better engineers in the future.”
Before iron, steel, and steel-reinforced concrete changed architecture forever, most civilizations made large buildings out of masonry: stones, bricks, mortar, and unreinforced concrete like the kind that ancient Romans used to construct the Pantheon’s dome. Builders relied on rules based on accumulated experience. The foundations of their designs were arches and vaults, which allowed heavy and brittle materials to reach long spans and soaring heights.
“A fundamental design goal was to build for generations, and to build for posterity,” Ochsendorf says. Builders chose granite, marble, and other durable materials. “They were working at a very high level and with high stakes,” he says. “If you invest the equivalent of millions of dollars into a structure, you don’t want to invest it in some amateur who doesn’t know if it’s going to stand up or not,” he says.
The Pantheon, which was completed in 125, is one example of such a high-stakes building. Its Greek-style, columned portico opens up into a massive rotunda, topped by a concrete dome that extends 142 feet in height, the largest unreinforced concrete dome in the world, with an open oculus that lets light, rain, and the occasional snowflake onto the floor below. It has withstood centuries of storms, earthquakes, abandonment, and reuse, in spite of wide fissures snaking up its dome.
With the Industrial Revolution, new materials changed buildings forever. They made it possible to create higher and broader structures with fewer resources. Building codes—uniform standards for building materials and design—which proliferated after the great urban fires of the 19th century, helped to phase old ways of building out of existence. They made buildings far safer, but paradoxically shut the door on ways of building that had been used for millennia.
Adapted from http://nautil.us/issue/24/error/why-we-should-let-the-pantheon-crack