Prof. Hoe Ling
Earth Institute Contact: Prof. Hoe Ling
This action is taken within the NSF Faculty Early Career Development (CAREER) Program, NSF 00-89, to support a research/education career project in the use of geosynthetic-reinforced soil structures to resist strong earthquake shaking. Geosynthetics provide a cost-effective solution in reinforced soil technology for many civil engineering structures. They have been applied widely as geosynthetic-reinforced soil retaining walls (GRS-RW), especially modular block GRS-RW that has gained wide popularity because of its pleasing esthetics. But structurally, these and other uses of geosynthetics serve a much more critical purpose in resisting seismic activity. While the performance of such geosynthetic-reinforced soils under routine (static) loads, and even minor earthquakes, has been good, recent experience indicates that improved knowledge and performance is needed regarding their response under strong earthquake shaking. In the 1999 Taiwan earthquake that produced large acceleration together with a large vertical component of that acceleration, several geosynthetic-reinforced soil structures collapsed. Clearly, available analysis and design procedures did not account for such severe dynamic loading. It is this shortcoming that is addressed in this research and education program. The project builds upon prior experimental and numerical research, and international cooperation with researchers in Japan undertaken by the PI. State-of-the-art shaking table facilities in Japan are used to test models under complex dynamic loading conditions, including vertical acceleration, in order to understand better the failure modes. The result is an improved characterization of the soil, the geosynthetic reinforcement, and their interaction. Additional parametric studies will result in a simplified procedure that enables GRS-RW to be designed based on permanent displacement. In addition to the technical value to the design community, this research program also provides a valuable tool for education. Two specific educational applications are addressed. First, the courses on geosynthetic waste containment and geotechnical earthquake engineering will use the results directly, as will the web based home page that already presents the PI's current research. In addition, a web based software package (Java Geotech) will be developed, and will join the currently active Geotech Forum for undergraduates. Second, this project, which involves applications in currently appealing areas of earthquake resistance and environmental remediation, will serve to encourage high school students, and especially minority students, to pursue studies relating to these areas. This will be accomplished through two Columbia University related programs to encourage interest in science and engineering among minorities: the Double Discovery Center and the Salvadori Education Center. Working through these Centers, teaching modules on reinforced soil structures and waste containment systems can be presented through lectures and laboratory demonstrations in high schools and through field trips, such as to JFK International Airport that is currently undergoing expansion.
Earth Engineering Center (EEC)
Cross Cutting Themes:
Hazards and Risk