1. Associate professor, College of Civil and Transportation Engineering, Hohai Univ., Xikang Rd. 1#, Jiangsu, Nanjing 210098, P.R. China.
2. Ph.D. Candidate, College of Civil and Transportation Engineering, Hohai Univ., Xikang Rd. 1#, Jiangsu, Nanjing 210098, P.R. China.
3. Professor, College of Civil and Transportation Engineering, Hohai Univ., Xikang Rd. 1#, Jiangsu, Nanjing 210098, P.R. China (corresponding author).