1. Associate Professor, Key Laboratory of High-Speed Railway Engineering, Ministry of Education, Chengdu 610031, China; Associate Professor, School of Civil Engineering, Southwest Jiaotong Univ., Chengdu 610031, China.
2. Professor, Key Laboratory of High-Speed Railway Engineering, Ministry of Education, Chengdu 610031, China; Professor, School of Civil Engineering, Southwest Jiaotong Univ., Chengdu 610031, China.
3. Professor, School of Civil and Construction Engineering, Oregon State Univ., Corvallis, OR 97330 (corresponding author).