March 31, 2010
Stanford engineering professor returns from Haiti and Chile resolved to improve earthquake construction education
By David Orenstein
During recent trips to study the damage in Haiti and Chile, Stanford earthquake engineering expert Eduardo Miranda witnessed firsthand the lesson of those disasters: What engineers already know about how to build for earthquakes can save hundreds of thousands of lives.
The ability of Chilean structures to withstand the magnitude 8.8 quake that struck on Feb. 27 appears to be a success story for seismic construction knowledge, said Miranda, an associate professor of civil and environmental engineering. But Haiti's suffering after the magnitude 7.0 quake that struck on Jan. 12 a quake 500 times less powerful than Chile's was the result of a tragic failure to establish and enforce building codes.
While Chile certainly sustained extensive economic damage, its basic structures were engineered well enough to save all but 452 lives. In Haiti, virtually everything that could be wrong was, leaving the impoverished population vulnerable to the earthquake to a despairingly high degree, with as many as 220,000 deaths.
"For Haiti, by far the biggest lesson is how we failed to transmit what we know to other parts of the world," Miranda said. "We know how to build against earthquakes and we know what regions are affected by earthquakes, but this knowledge has not been transmitted to all the regions that need it."
After traveling to Haiti and seeing a collapsed nation in disarray, Miranda says he is committed to increasing earthquake engineering education in Haiti. He said he will work with nongovernmental organizations in the area to help them establish curricula for engineers, builders and homeowners as the nation's massive reconstruction effort, made possible largely because of financing from international donors, gets under way.
Even though Haitians are very poor, Miranda said they can build much better structures with the same materials they've used before, if only they do it with better information learning, for instance, how to tie structural elements together more effectively.
In post-quake Chile, Miranda said, the need is completely different. There, the biggest issue is the same as in much of the developed world: how to improve the seismic performance of non-structural elements, such as water pipes and ceilings. The widespread rupture of pipes in the Santiago airport, for example, resulted in major flooding that did tens of millions of dollars of damage.
Although he saw isolated building collapses, Miranda said that many Chilean buildings need repair rather than rebuilding.
Haiti needs complete 'restart'
Haiti's lack of preparedness for earthquakes began years before the temblor struck, Miranda said. Long impoverished, Haiti also has become more politically fragile in the last decade. Just as the political situation seemed to be improving in 2008, the country was battered by four hurricanes.
Because hurricanes are so frequent and earthquakes are so rare a major earthquake hadn't struck Haiti in about 150 years Haitians often poured their meager resources into buildings with heavy roofs that would withstand high winds. Virtually no attention was paid to seismic concerns.
When the quake struck, Haitians found themselves in buildings that were prone to collapse. And the heavy roofs that had seemed like lifesavers in hurricanes fell, crushing the building's occupants.
Most Haitians build their homes themselves because they cannot afford to hire builders. "Your expertise comes from your father or your uncle, or a neighbor who might know something about construction," Miranda said. "You would never hear your father or grandfather talk about earthquakes because no one had ever experienced this."
More than five weeks after the Haiti quake, Miranda said, the country remained completely dependent on international aid. But as much help as there was, it was clearly insufficient to sustain the population of Port-au-Prince, the capital city of 2 million people. Tent cities were being taken over by gangs and there was not enough drinking water to go around, Miranda said.
With about 80 percent of Haiti's government buildings destroyed and very little surviving infrastructure, Miranda said, the country is rebuilding essentially from scratch.
"You have to think of restarting the country, because that is what it's going to take," he said.
Chile damaged but structures sound
In stark contrast to Haiti, Chile has emerged from its catastrophe as a model of earthquake resistance. Not only is the nation much more economically prosperous and politically stable than Haiti, but it has the experience of dealing with monstrous earthquakes that strike every decade or so. The strongest earthquake ever recorded, a magnitude 9.5, hit the country in 1960.
For all those reasons, Chile has earthquake codes and standards that are comparable to those in the United States, Miranda said.
"In Chile, the biggest lesson is the success of earthquake-resistant design," Miranda said. "This earthquake shows us how structures that have been designed according to current codes are capable of sustaining earthquakes without collapse, protecting the lives of their occupants."
But there is no question that Chileans, too, suffered tremendously. Earthquake codes are designed to prevent total collapse but do not focus on preventing non-structural damage. Consequently, estimates of the economic losses in Chile range between $20 billion and $30 billion, Miranda said. The nation's gross domestic product last year was roughly $244 billion.
Miranda said studying the performance of buildings, bridges, roads and ports in Chile will help earthquake engineers further their knowledge of what can be done to limit not only fatalities but also economic damage.
Miranda's hope is that engineers will do a better job of getting that word out to everyone who needs to know.
David Orenstein is the associate director of communications at the Stanford School of Engineering.