1. Professor, Dept. of Civil Engineering, Shanghai Univ., 99 Shangda Rd., Shanghai 200444, China.
2. Ph.D. Candidate, Dept. of Civil Engineering, Shanghai Univ., 99 Shangda Rd., Shanghai 200444, China (corresponding author).
3. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Louisiana State Univ., Baton Rouge, LA 70803.