1. Ph.D. Candidate, College of Civil Engineering, Hunan Univ., Changsha, Hunan 410082, China.
2. Professor, College of Civil Engineering, Hunan Univ., Changsha, Hunan 410082, China (corresponding author).
3. Professor, Dept. of Civil, Architectural, and Environmental Engineering, Univ. of Miami, Coral Gables, FL 33146.