1. Professor, State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao Univ., Shijiazhuang 050043, China; Professor, School of Civil Engineering, Shijiazhuang Tiedao Univ., Shijiazhuang 050043, China.
2. M.Sc. Student, School of Civil Engineering, Shijiazhuang Tiedao Univ., Shijiazhuang 050043, China.
3. Professor, School of Civil Engineering, Shijiazhuang Tiedao Univ., Shijiazhuang 050043, China.
4. Research Assistant, Dept. of Civil and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum D-44780, Germany (corresponding author).