1. Research Assistant, College of Civil Engineering, Hunan Univ., Changsha, Hunan 410082, China.
2. Professor, Key Laboratory for Wind and Bridge Engineering of Hunan Province, Hunan Univ., Changsha, Hunan 410082, China (corresponding author).
3. Professor, Dept. of Civil and Environmental Engineering, Louisiana State Univ., Baton Rouge, LA 70803.
4. Research Assistant, Dept. of Civil and Environmental Engineering, Louisiana State Univ., Baton Rouge, LA 70803.