Researchers at Rensselaer are leading a $7 million project to develop a new comprehensive system for monitoring and assessing the condition of aging levees and dams.
|A Prescription for Healthier,
Longer-Lived Levees and Dams
The four-year project, which includes $3.5 million in funding from a U.S. National Institute of Standards and Technology (NIST) Technology Innovation Program grant, aims to create an integrated suite of technologies and methods for ensuring the reliability and safety of flood-control infrastructure. Rensselaer will partner with Geocomp Corp. on this new framework, which incorporates satellite-based radar with GPS and locally installed sensors. Such a system could help to significantly reduce the risk of catastrophic events akin to the 2005 New Orleans levee failure during Hurricane Katrina.
“The challenges of monitoring and assessing large infrastructure systems in varying stages of deterioration are among the most pressing we face as a nation,” said David Rosowsky, dean of engineering.
“The unique ability of Rensselaer faculty to bring together a large-scale, integrated approach to address the problem of catastrophic flood control will help bring safety and security to millions of people in the future,” said Provost Robert Palazzo.
“Currently, most infrastructure assessments are based on infrequent visual inspections of the surface condition of levees and dams, which in reality reveal very little about the internal condition and performance of these structures. It’s like a medical doctor conducting an annual checkup based solely on the external appearance of a patient,” said Mourad Zeghal, associate professor in the Department of Civil and Environmental Engineering, who is leading the project.
“Our project sets out to develop a new, more effective means to continuously monitor and analyze, in real time, the internal and external health of levees and dams. The proposed framework is cost-effective, robust, minimally invasive, and should boost the safety and reliability of our national flood-control infrastructure,” he said.
The project’s capstone experiment includes participating in a $5 million test by the U.S. Army Corps of Engineers that involves intentionally breaching, or loading until failure, a full-scale levee.
Co-investigators on the project are Tarek Abdoun, the Iovino ’73 Career Development Professor in Civil Engineering and acting head of the Department of Civil and Environmental Engineering, and Birsen Yazici, associate professor in the Department of Electrical, Computer, and Systems Engineering. Abdoun led Rensselaer’s physical modeling research team that clarified the failure mechanisms of some of the New Orleans levees during Hurricane Katrina, providing critical feedback to the corresponding numerical analyses. Yazici is leading an $800,000 U.S. Air Force research project to create a new laboratory for developing and testing next-generation radar systems.
Among the long-term monitoring techniques proposed for the levee assessment framework is InSAR, or satellite-based interferometric synthetic aperture radar measurements. InSAR will capture and analyze high-resolution satellite images of levees and dams, and measure how far these structures have shifted or sunk due to environmental changes such as rain, floods, tremors, or even aging. InSAR measurements are accurate down to the millimeter scale.
The proposed framework also calls for sensor arrays to be installed into the ground beneath and around levees and dams. These SAPP (shape-acceleration-pore pressure) arrays are inexpensive and will help to accurately measure soil deformation, vibration, and pore pressure at critical points of a flood-control system. To bridge the gap between InSAR satellite data and below-ground SAPP measurements, the researchers will augment the framework with a network of high-resolution GPS sensors to track the physical movement of structures.
Data collected from the three systems will be integrated into an automated “smart network” that provides, for the first time, a long-term continuous assessment of the health of levee systems from both underground and aerial perspectives, Zeghal said. In case of a levee failure, data collected by the proposed automated monitoring system will be used to organize a quick emergency response to repair levees and minimize the extent of flooding.
For additional information on levee and earthquake research conducted at Rensselaer, visit http://nees.rpi.edu. For more information on Rensselaer’s contributions to national efforts in responding to Hurricane Katrina, go to www.eng.rpi.edu/ magazine/img/sp06/pdf/Sp06_SoeNews_Katrina-1.pdf