1. Assistant Professor, Dept. of Bridge Engineering, School of Civil Engineering, Southwest Jiaotong Univ., Sichuan 610031, China; Key Laboratory of High-Speed Railway Engineering of the Ministry of Education, Sichuan 610031, China; Visiting Scholar, Dept. of Civil and Environmental Engineering, Univ. of Tennessee, John D. Tickle, Knoxville, TN 37996.
2. Professor, Dept. of Bridge Engineering, School of Civil Engineering, Southwest Jiaotong Univ., Sichuan 610031, China.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Tennessee, John D. Tickle, Knoxville, TN 37996; Visiting Professor, School of Civil Engineering, Southwest Jiaotong Univ., Sichuan 610031, China (corresponding author).