1. Ph.D. Student, Dept. of Civil Engineering, Shanghai Jiao Tong Univ., 800 Dongchuan Rd., Shanghai 200240, China.
2. Associate Professor, Dept. of Civil Engineering, Shanghai Jiao Tong Univ., 800 Dongchuan Rd., Shanghai 200240, China (corresponding author).
3. Professor, Dept. of Civil Engineering, Shanghai Jiao Tong Univ., 800 Dongchuan Rd., Shanghai 200240, China.