1. Ph.D. Candidate, Dept. of Applied Mechanics and Engineering, School of Engineering, Sun Yat-sen Univ., Guangzhou 510275, China.
2. Professor, Dept. of Applied Mechanics and Engineering, School of Engineering, Sun Yat-sen Univ., Guangzhou 510275, China (corresponding author).
3. Professor, Dept. of Civil and Environmental Engineering, and Center for Computation and Technology, Louisiana State Univ., Baton Rouge, LA 70803.
4. Professor, School of Civil and Construction Engineering, Oregon State Univ., Corvallis, OR 97331.