1. Professor Emeritus, Dept. of Civil and Environmental Engineering, Hong Kong Univ. of Science and Technology, Clear Water Bay, Hong Kong SAR, China (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, CA 95616; and, Dept. of Mechanics, School of Applied Mathematical and Physical Sciences, National Technical Univ. of Athens, Zographou, 15773 Athens, Hellas.