RENSSELAER POLYTECHNIC INSTITUTE MODEL OF NEW ORLEANS LEVEE POINTS TO LAYER OF CLAY

Preliminary findings suggest that during Hurricane Katrina, the 17th Street Canal levee in New Orleans may have slid on a layer of weak clay beneath the peat that underlies the earthen structure. Researchers at Rensselaer Polytechnic Institute in Troy, N.Y., have developed a small-scale centrifuge model showing the 17th Street Canal levee during Hurricane Katrina conditions.

The U.S. Army Corps of Engineers Hurricane Katrina Interagency Performance Evaluation Task Force selected Rensselaer engineers to test small-scale centrifuge models of sections of the flood-protection system from locations in New Orleans, including the 17th Street Canal and the London Avenue Canal. They are attempting to replicate conditions during Hurricane Katrina by subjecting the models to flood loads.

Three small-scale models have been tested at Rensselaer and at the Corps’ Engineer Research and Development Center in Vicksburg, Miss.

In the 17th Street model, the wall in the middle of the earthen structure started to move before the water reached the top, according to Tarek Abdoun, associate professor of civil and environmental engineering at Rensselaer. He also noted that the weak clay directly underneath the peat layer sheared first, causing the whole levee to slide.

“Our centrifuge models have already produced some valuable information, which not only will provide the Corps with important scientific data as they move forward, but also could give engineers around the world a better understanding of how levees respond under extreme conditions,” Abdoun said, but added the results are preliminary.

The final report to be completed by June 1, will be validated by an external review panel from the American Society of Civil Engineers.

View video footage of a small-scale centrifuge model of the 17th Street Canal at http://www.rpi.edu/news/levees.