1. Ph.D. Student, Dept. of Civil Engineering, Central South Univ., Changsha, Hunan 410075, China; presently, Visiting Ph.D. Student, Dept. of Civil and Environmental Engineering, Rutgers, State Univ. of New Jersey, Piscataway, NJ 08854.
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Rutgers, State Univ. of New Jersey, Piscataway, NJ 08854 (corresponding author).
3. Professor, Dept. of Civil Engineering, Central South Univ., Changsha, Hunan 410075, China.