‘If It Keeps On Rainin’, Levee’s Goin’ To Break’*
Usama El Shamy was teaching at Tulane University
when Hurricane Katrina hit Louisiana and
Mississippi. His research into the impact of floodwater
on levee systems in general had led him to conclude
that their failure in New Orleans was an imminent
possibility. And then the worst-case scenario unfolded
before his eyes.
Now an assistant professor of environmental and
civil engineering in SMU’s Bobby B. Lyle School of
El Shamy is breaking new ground in his
levee systems research. The first problem with most
existing systems is their age, he says. For example, the
levees that stand between the petrochemical plants of
Texas City, Texas, and the next Hurricane Ike were
built in the 1960s, and their construction shows it.
“It’s unfortunate that these crucial structures have
been designed with such outdated concepts.”
To counter those problems, El Shamy and a team of
students are conducting advanced research with basic materials – examining and modeling soils at a particle
scale to capture their interactions with flowing water and to predict the potentially disastrous shifts
that may result when floodwaters saturate a levee.
El Shamy focuses on levee systems that are built on saturated sand. “Plenty of those levees exist now,”
he says. “We have them here in Dallas, in fact. And they’re not only susceptible to floodwater, they’re also
susceptible to intense rainstorms. I want to find out how that kind of storm impacts a levee system.”
To that end, El Shamy is using computer-modeling tools to develop an inventory of characteristics that
make stronger levees. Standard levee modeling puts too much focus on the impact of flowing water, he
says. “Water seepage will make the soil move and deform, but the levee also has weight – and this weight
is trying to sink even as the water is flowing.” The combination of seepage and sinking accelerates structural
failure if the effect of the weight is ignored or underestimated, he adds.
By taking the impact of that
weight into account, engineers will be able to create much safer systems.
“I envision a worst-case scenario and use computer modeling to try to fix it,” he says.
In a similar vein, El Shamy also is part of a nationwide university team investigating the impact of seismic
activities such as earthquakes on building foundations. The group, which includes researchers from
Rensselaer Polytechnic Institute (RPI), the State University of New York-Buffalo and the University of
California-San Diego, is funded by the National Science Foundation.
“When pile foundations are subjected to seismic motion, their responses are very unpredictable. We’re
trying to understand their behavior by examining different aspects of the problem,” El Shamy says. His
work focuses on micromechanical simulation, while other institutions are working with large-scale
systems and computational simulations.
El Shamy earned his Ph.D. degree in civil engineering from RPI under a National Science Foundationfunded
project in which he first began modeling soils at a micro scale. At SMU, he says, “I have found a
place where I can excel in my work and do the things that I like.”
For more information: lyle.smu.edu/ence
* (From a blues song recorded in 1929 by Kansas Joe McCoy and Memphis Minnie in reaction to the devastation
caused by the Great Mississippi Flood of 1927.)