Chandra Desai Receives ASCE Award

Dr. Chandra S. Desai, Regent’s Professor of Civil Engineering and Engineering Mechanics at the University of Arizona has been selected by the ASCE Geo-Institute Board of Governors to receive the 2007 Karl Terzaghi Award. This is one of the most prestigious awards given by the Geo-Institute.  Dr. Desai is recognized for his outstanding, seminal and sustained contributions in Geotechnical Engineering and Geomechanics for the development of constitutive models, testing devices and computer methods , and their use for solutions of a wide range of practical problems.. In making this selection, the committee particularly noted his pioneering and lifelong contributions to the application of numerical methods and constitutive modeling to Geomechanics.

Since graduating in 1968 with a doctoral degree from the University of Texas, Austin, Texas, Dr. Desai has made significant and original contributions in geotechnical engineering. They have involved both research and practical applications in wide areas such as seepage and stability, consolidation, foundations (shallow and deep), reinforced earth,  laboratory testing, static and dynamic soil-structure interaction, liquefaction , pavement and track support structures, lunar materials, constitutive modeling and computer (finite element) methods.

He has authored/coauthored about 300 papers in refereed journals and conferences, about 20 text books and edited volumes, and about 20 chapters in books. These are predominantly in the area of Geotechnical engineering and Geomechanics. Since 1970, he has published over 33 papers in the ASCE – Geotechnical/Geo-Institute journals (Journal of Soil Mechanics and Foundations Division, Journal of Geotechnical Engineering, Journal of Geotechnical and Geoenvironmental Engineering), and the papers on  engineering/geomechanics have also been published in other journals such as Journal of Engineering Mechanics-ASCE, Journal of Structural Engineering-ASCE, International Journal of Numerical and Analytical Methods in  Geomechanics, International Journal of Earthquake Engineering and Structural Dynamics, Japanese Journal of Soil Mechanics and Foundation Engineering, International Journal of Solids and Structures, Geotechnical Testing-ASTM, International Journal of Rock Mechanics and Mining Sciences, Journal of Water Resources Research, Journal of Geophysical Research, and Transportation Research Board.

Because of the generality of his work related to computer methods and constitutive modeling, his text books and papers have been used in other engineering disciplines such as mechanical, aerospace and mining engineering. Dr. Desai’s research in constitutive modeling for geomaterials has found applications in other areas such as electronics packaging for analysis and reliability of chips-substrate systems, and geosciences for movement of ice sheets on glacial tills.  These contributions have involved participation by about 50 doctoral and 50 master’s students guided by Dr. Desai.

Constitutive Modeling: Dr. Desai’s work involves continuous and sustained development of progressively refined materials models for soils, rocks and interfaces/joints. He is responsible, with his students and coworkers, for developing the disturbed state concept (DSC), which provides a basis for adopting and using models that account for progressive factors influencing behavior of geomaterials, in a hierarchical framework. It is unified and yet simplified for practical use and contains models such as elastic, plastic, creep, critical state, softening (degradation) and healing under mechanical, fluid and thermal loads, as special cases. As a result, the DSC model provides the user with the option to choose specific model required for the material in practical problems. The DSC has been applied successfully to model behavior of soils, rocks, interfaces/joints, and other materials such as concrete, asphalt concrete, ceramics, metals, solder and silicon. The DSC model has been implemented in general and nonlinear finite element procedures including coupled behavior of saturated soils. It has provided highly satisfactory predictions for a large number of practical geotechnical problems.

Laboratory Testing: Recognizing the need for appropriate and required laboratory and field-testing to establish the validity of computer methods and constitutive models, Dr. Desai’s work has involved comprehensive use of laboratory tests for calibration of models for geologic materials and interfaces/joints. He has initiated and actively participated in design, fabrication and use of the following new test devices: (a) Cyclic Multi-Degree of Freedom Device for testing of dry and saturated interfaces and joints. (b) A multiaxial/cubical test device with measurements of displacements (strains), pore water pressures and nondestructive quantities such as P-wave velocity to identify damage and anisotropy in soils; (c) A triaxial device for testing lunar material under vacuum, and (d) The Thermomechanical digital correlation (TMDIC) device for testing of micro level interfaces and measurements of strains, stresses and gradual development of strain localization, microcracking, fracture and failure.

Seepage and Stability and Consolidation: The residual Flow Procedure (RFP) for free surface seepage developed by Dr. Desai has been original and has removed the need of the use of fixed (finite element) mesh, which entailed various computational difficulties. Together with the use of this procedure, he developed a Parallel Plate model for laboratory validations, and also validated field observations in riverbanks and dams. Further, he has developed 1-, 2- and 3-dimensional computer procedures for consolidation and settlement analysis and applied them for solution of practical problems. These have included realistic constitutive models such as critical state and DSC.

Soil-Structure Interaction: He has made significant contributions to static and dynamic analyses of footings, navigation lock structures, field piles in clays and sands, reinforced earth, and piles in centrifuge.  His research has involved material modeling, testing and verifications for measurements in the field and laboratory. For example, his work on the development of the “thin layer interface element” can be considered significant and original. It has provided improved and realistic predictions of soil-structures interaction effects, and has been used by many researchers and practitioners. Also, his work, with appropriate models for interfaces, can be considered pioneering for identification of realistic variations of stress at interfaces between structures and soils, arching effects, and liquefaction in zones involving interfaces.

Pavements and Track Support Structures: Dr. Desai has developed two- and three-dimensional computer procedures with realistic constitutive models for pavements and railroad track support structures. His recent work with the use of the unified DSC model for both bound (concrete, asphalt) and unbound (base and sub base soil materials) can be considered significant for analysis, design and maintenance of such structures.

Lunar Materials: Dr. Desai has developed a new thermal liquefaction procedure for developing structural and foundation materials by using lunar (powdered rock) stimulants. Such a procedure can be used to manufacture construction materials from lunar regolith using the solar energy on the moon.

Because of Dr. Desai’s outstanding and original contributions, he was awarded the title of Regents’ Professor at the University of Arizona. He has received the Alexander von Humboldt-Stiftung U.S. Scientist Prize, Outstanding Contribution Medal by the Czech Society of Mechanics of Czech Academy of Sciences, Distinguished Contributions Medal by the International Association for Computer Methods and Advances in Geomechanics(IACMAG), the Clock Award for Outstanding Contributions to mechanics and thermal sciences by the Electrical and Electronic Packaging Division, American Society of Mechanical Engineers, and the El Paso Natural Gas Foundation Faculty Achievement Award for teaching and scholarship at the University of Arizona.

Dr. Desai is the founding President of the IACMAG and founding Editor-in-Chief of the International Journal of Geomechanics (IJOG) by the Geo Institute, ASCE.

The International Association for Computer Methods and Advances in Geomechanics (IACMAG) congratulates Dr. Desai for his selection of the 2007 Karl Terzaghi Award.