*** 9623979 Pestana The importance of a rational approach to understanding the dynamic behavior of sands has grown with an increased awareness of the relationship between local conditions and the dynamic loading resulting from earthquakes. In particular, the experience and data gathered from the 1989 Loma Prieta and 1995 Hyogoken-Nambu (Kobe) earthquakes clearly indicate that most of the ground failures appear to have been the result of liquefaction of cohesionless materials; predominantly loose, saturated hydraulically-placed fills. Overall, liquefaction played an important role in the extensive damage experienced by these port facilities. These events, including the October 1995 Mexico earthquake, are ever present and thus the need to quantify potential damage and assess the risk associated with these natural hazards. The objectives of this research program are: a) development of an advanced constitutive model able to describe the observed behavior of cohesionless soils during cyclic loading, and the evaluation of its performance through selected comparisons with reliable laboratory data; b) implementation of this advanced soil model into a finite element formulation with dynamic capabilities; and c) application to the assessment of the seismic response of cohesionless soils thorough fundamental parametric studies of soil-structure interaction, such as the performance of deep foundations. The educational goals are: a) To foster the integration of research and education; b) increase involvement of undergraduate students in research; and c) maximize the exchange between education and engineering practice and design. These goals are approached from the perspective of the following important factors: a) Trends and innovative thinking in engineering research; b) innovative instructional techniques; and c) involvement in the engineering state-of-practice. The research will contribute to the fundamental understanding and prediction of factors such as volume change, shear modulus, dampin g and time effects during cyclic loading, and may be applicable to all liquefiable soils. The incorporation of the constitutive model into a finite element code to predict soil-structure interaction, including earthquake induced permanent deformation, represents a significant contribution earthquake hazard mitigation. The education program will foster the involvement of undergraduate students in engineering design projects, and will encourage graduate students to learn the fundamental concepts and make critical use of available tools and techniques to succeed in their professional practice.***
