RESISTING THE SURGE
NSF grant allowing researchers to measure impact of surge on humans and bridges

The binder containing all of the federal specifications for bridge design in the U.S. is almost six inches thick. Yet, it contains no guidance or regulations about how to design coastal bridges to resist storm surge.

The death toll for Katrina fluctuates depending on the criteria. Previous research indicates that there is a strong relationship between casualty rates and depth of flooding, but the effects of other circumstances are not as well understood.

The fact that there is little information on storm surge impact on bridges and casualties concerns researchers at the LSU Hurricane Center. About 15 bridges were destroyed or damaged along the Gulf Coast because of Hurricane Katrina and still thousands more lie in the U.S hurricane zone from Texas to Maine.

These two concerns of bridges and flood casualties prompted LSU researchers Marc Levitan, Ivor van Heerden, Ayman Okeil, and Steve Cai to submit a proposal to the National Science Foundation that would address both concerns and allow them to immediately begin collecting perishable data in New Orleans—data that could be lost because of time and the recovery efforts.

“Katrina’s storm surge was probably the largest in recorded U.S. history in terms of both geographic area and intensity,” says Levitan, director of the LSU Hurricane Center and the Charles P. Siess, Jr. Associate Professor of Civil and Environmental Engineering. “I’ve been studying hurricanes for 20 years. There is no precedent in recent US history for a storm to cause such catastrophic loss of life and damage to the built environment. It is therefore extremely important that we work quickly to capture and record the perishable information from the storm. Analysis of this data can then be used to develop strategies to minimize the hurricane impacts on people and structures in the future.”

The first task of the project calls for the collection of detailed data on the conditions surrounding as many individual fatalities as possible. Levitan and van Heerden, LSU Hurricane Center deputy director, will look at such factors as the location; depth of water; demographic data; whether or not the fatality occurred in building, car or open area; and the building type, elevation, and damage sustained. This data will allow researchers to develop better flood fatality models, which are extremely valuable to emergency managers and public health officials for disaster planning, search and rescue operations, and recovery operations.

The second task is focused on bridge damage data collection. Researchers are surveying short- and medium-span bridges that performed poorly during both Hurricane Katrina and Hurricane Ivan, which struck the Gulf Coast last year. Okeil and Cai, both assistant professors in the Department of Civil and Environmental Engineering, are leading efforts to examine bridge factors such as the way the bridge failed, corrosion, high water mark elevations, and bridge railings. This data is essential to rehabilitating and building more reliable coastal bridges. –J.T. Lane

ON THE WEB:
LSU Hurricane Center
Center for the Study of Public Health Impacts of Hurricanes

from Storm Issue 2005