1. School of Civil and Transportation Engineering, Hohai University, Nanjing, P. R. China; Jiangsu Transportation Research Institute, Nanjing, P. R. China
2. School of Civil Engineering, Nanjing Tech University, Nanjing, China
3. School of Civil Engineering, Nanjing Tech University, Nanjing, P. R. China (corresponding author: )
4. School of Civil Engineering, Nanjing Tech University, Nanjing, P. R. China