Withstanding Disasters: Profiles in protection
Earthquakes, tsunamis, fires, floods, droughts -- there are no easy answers when it comes to natural disasters. But, that doesn’t mean we must be powerless in their wakes. Civil and environmental engineers are tackling big questions in efforts to increase understanding, prepare for, and, when possible, prevent major disasters.
What are the similarities in the devastating structural damage caused by tsunamis, hurricanes and storm surges?
Assistant Professor of Civil and Environmental Engineering Julie Young studies recent natural disasters, including the 2004 Indian Ocean tsunami and Hurricane Katrina, in an effort to provide understanding that will ultimately inform building guidelines and prevent the horrors from playing out again in the future. Much of the damage from all of these disasters, she has found, results from the potent interplay of multiple forces acting on buildings from all sides, including moving walls of water, extreme winds and shifting soils (see story, page 8). Young will next turn her attention to soil-structure systems along the Pacific coast of Oregon and Washington, where geologic conditions are primed for a massive combined earthquake-tsunami event.
When the earth quakes, how does the soil respond?
In an earthquake, soil often behaves like a liquid, according to Jean Prévost. For more than 20 years, the civil and environmental engineering professor has studied a phenomenon called “liquefaction,” which causes water-saturated soil or sand to flow like a fluid. Most often associated with earthquakes, but sometimes observed during tsunamis, this phenomenon causes extensive damage to structures built atop such an unstable foundation. Recently, Prevost has looked at how variation in the shape, size and composition of soil particles can actually increase the risk of liquefaction. “Typically, engineers work with averages, but, for this purpose, they should pay attention to the extremes to be prepared for the weakest links,” he said.
How can high-rise buildings be designed to survive earthquakes and fires?
If Maria Garlock has her way, structures will one day return to an upright position after being shaken to their cores by earthquakes. An assistant professor of civil and environmental engineering, Garlock is working to develop self-centering steel frames for skyscrapers, which often survive earthquakes but suffer severe structural damage during the events. Garlock’s work also includes extensive analyses of how fire exposure affects the steel columns that form the skeletons of tall buildings, as well as the design of sensors capable of assessing and monitoring building conditions.
From thunderstorms to severe floods, how does urbanization affect the weather?
James Smith, a professor of civil and environmental engineering, is demonstrating that cities have an impact on their environment that extends beyond increasing air pollution to intensifying severe weather events, such as floods and thunderstorms. Smith works with observational data and computer models to gauge how urban environments shape meteorological conditions (see story, page 9). His work as part of the National Science Foundation- funded Baltimore Ecosystem Study has explored the city’s thunderstorms, floodplains and urban rivers, and his research also includes intense monitoring of the Harry’s Brook Watershed near the Princeton campus.
As global warming continues, will the United States become more susceptible to drought?
By economic measures, drought is the nation’s most costly natural disaster and many climate simulations have indicated that global warming is likely to increase the incidence of drought in the country’s interior. But these computer models ignore many important parameters, which Eric Wood, a professor of civil and environmental engineering, is incorporating into more realistic systems that will generate better predictions. For instance, Wood’s models will allow for interactions between the land surface and water cycle, and also consider the possible role of vegetation change as the Earth warms. In the photo above, New Jersey Governor Jon Corizine listens as Wood presents a report issued by the Union of Concerned Scientists on the effects of global warming.