1. Lecturer, School of Civil and Transportation Engineering, Hebei Univ. of Technology, Tianjin 300401, China (corresponding author).
2. Professor, School of Civil and Transportation Engineering, Hebei Univ. of Technology, Tianjin 300401, China.
3. Lecturer, School of Civil Engineering and Architecture, Zhejiang Sci-Tech Univ., Hangzhou 310018, China.
4. Lecturer, School of Civil Engineering, Changsha Univ. of Science and Technology, Changsha 410114, China.