1. Professor, Dept. of Mechanics, Faculty of Applied Mathematical and Physical Sciences, National Technical Univ. of Athens, Zographou 15780, Greece; also Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Davis CA 95616. E-mail: yfdafalias@ucdavis.edu
2. Research Fellow, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, CA 95616 (corresponding author). E-mail: loupapas@alum.mit.edu.
3. Associate Professor, Dept. of Civil Engineering, Hong Kong Univ. of Science and Technology, Hong Kong, China. E-mail: xsli@ust.hk