1. Lecturer, College of Civil and Transportation Engineering, Hohai Univ., Nanjing, Jiangsu 210098, P.R. China (corresponding author).
2. Graduate Student, College of Civil and Transportation Engineering, Hohai Univ., Nanjing, Jiangsu 210098, P.R. China.
3. Ph.D. Student, College of Civil and Transportation Engineering, Hohai Univ., Nanjing, Jiangsu 210098, P.R. China.