Breakthroughs in Earthquake Engineering: CAEE's Unique Field Testing Capabilities
Kenneth Stokoe, Professor and Director of Geotechnical Engineering Center
CAEE Faculty members Ken Stokoe and Ellen Rathje are currently involved in research that is making a substantial impact on the geotechnical earthquake engineering community in the United States. Their reseach will provide the basis for better predictions of how soil interacts with buildings, bridges, highway overpasses, and homes, thus leading to the development of infrastructure better suited to survive major quakes.
Between 2000 and 2004, Stokoe was the Principal Investigator (PI) on a $3 million National Science Foundation (NSF) grant in the NEES (Network for Earthquake Engineering Simulation) program. The NEES program encompasses 15 experimental sites that are networked together as a shared-use collaboratory that can be used by researchers throughout the country to study earthquake engineering. Along with CAEE Geotechnical Associate Professor Ellen Rathje and Clark Wilson, Geological Sciences Professor from the Jackson School of Geosciences, the UT team developed nees@UTexas, a unique experimental facility that focuses on field-testing. Operational since October 2004, nees@UTexas is a 50% shared-use facility with a yearly operating budget in excess of $850K from NSF.
Associate Professor Ellen Rathje
The nees@UTexas equipment includes three mobile shakers that have diverse force and frequency capabilities, an instrumentation van that houses state-of-the-art data acquisition systems, and a large collection of field instrumentation. The field equipment can be used in a variety of applications, including shear wave velocity characterization, liquefaction testing, geophysical testing, and dynamic testing of structures.
The equipment provides for field capabilities that have never before existed and is being used in research, with the oversight of the University of Texas team, by universities and governmental researchers around the United States. In the past four years, the mobile shakers at nees@UTexas have been used in research projects in the following areas: (1) deep shear-wave velocity profiling, (2) in-situ nonlinear shear modulus measurements of soil, (3) in-situ liquefaction tests, (4) soil-foundation-structure interaction studies, and (5) geophysical studies.
CAEE is helping to improve the understanding of sand aging and its influence on engineering.
The goal of NEES is to accelerate progress in earthquake engineering and to improve the seismic design and performance of civil and mechanical infrastructure systems through the integration of people, ideas, and tools in a collaborative environment. Open access and use of NEES research facilities and data by the earthquake engineering community—including researchers, educators, students, practitioners, and information technology experts—is a key element of this goal.
Kenneth H. Stokoe, Ph.D., is Director of the Geotechnical Engineering Center/Professor - Jennie C. Milton T. Graves Chair in Engineering. He has been working in the areas of in situ seismic measurements, laboratory measurements of dynamic material properties, and dynamic soil-structure interaction for the past 35 years. He has conducted major research efforts in the areas of nondestructive testing (NDT) of pavements, runways and geotechnical systems, and laboratory evaluation of soil and rock stiffness under cyclic and dynamic loading conditions.
The "Thumper" on-site in Hawaii, uses vegetable-based hydraulic oil.
Ellen Rathje, Ph.D., P.., is Associate Professor in Geotechnical Engineering and a J. Neils Thompson Centennial Teaching Fellow. The focus of her research is understanding and predicting geotechnical earthquake hazards, with particular emphasis on the evaluation of earthquake-induced ground failure (slope instability, soil liquefaction), the effect of soil conditions on earthquake ground motions, and the use of remote sensing to document earthquake hazards.
For more information about this project, please visit the project website.
To learn more about Ken Stokoe or his research, please visit his website.
For more on Ellen Rathje or her research, please visit her website.