1. Professor, Dept. of Civil Engineering, Dalian Univ. of Technology, Dalian 116024, China (corresponding author).
2. Former Graduate Student, Dept. of Civil Engineering, Dalian Univ. of Technology, Dalian 116024, China; Shanxi Transportation Research Institute, Taiyuan 030000, China.
3. Professor, Member of Chinese Academy of Engineering, Dept. of Civil Engineering, Dalian Univ. of Technology, Dalian 116024, China.