1. Associate Professor, School of Civil Engineering and Architecture, Changsha Univ. of Science and Technology, Hunan, Changsha 410004, China (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Louisiana State Univ., Baton Rouge, LA 70803.
3. Professor, School of Civil Engineering and Architecture, Changsha Univ. of Science and Technology, Hunan, Changsha 410004, China.
4. Professor, College of Civil Engineering, Hunan Univ., Hunan, Changsha 410082, China.