This project supports collaborative research by Dr. Alaa Ashmawy, Department of Civil Engineering, University of South Florida (USF), Tampa, Florida and Dr. Ahmed Abdelrahman, National Research Center (NRC), Cairo. They plan to study the modeling and analysis of geogrid-reinforced earth structure under earthquake loading.
Intellectual merit: The mechanical response of Mechanically Stabilized Earth (MSE) walls to earthquake loading is not fully understood. While MSE structures perform well in terms of overall stability during earthquake loading, the deformation and distress behavior, as well as the change in internal stress state, have not been widely investigated. The PI has designed a new multi-purpose geosynthetic testing apparatus capable of performing pullout and shear testing on a wide range of soil-geogrid systems. The apparatus, currently housed at the NRC in Egypt, is to be utilized to investigate the cyclic interaction between granular soils and geogrid inclusions. An experimental program will be carried out by the Egyptian collaborators to examine the cyclic stress-deformation characteristics of soil-inclusion interfaces in relation to reinforcement stiffness and inclusion geometry. A servo-control system will be added to the existing equipment to enhance its testing capabilities. Numerical modeling of the system will be conducted at the USF using finite element/finite difference software to verify and calibrate the experimental data. Modifications to the current reinforced earth design and geogrid manufacturing standards will be proposed accordingly. The proposed research activities will fill in a gap in the area of stress-deformation characteristics of reinforced soil system under cyclic or dynamic loading. The NRC Cairo will provide the infrastructure needed for the experimental study. The software and numerical tools are, in parallel, available at the USF. The findings can have significant implications to the repair and long-term maintenance of MSE walls subjected to earthquake loading.
Broader Impacts: The outstanding qualifications of the Egyptian collaborator and the support provided by his institution will ensure the development of high quality experimental data for analysis. A highly qualified American graduate student has already been identified and recruited by the PI to participate in the research and will commence her graduate studies in Summer 2005. She will visit the Egyptian institution and labs. Broad dissemination of research findings will be secured through publication in journals, conference proceedings, and the Internet. This project is being supported under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to carry out these cooperative activities.
