1. School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang, P. R. China
2. State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang, P. R. China
3. School of Traffic and Transportation, Shijiazhuang Tiedao University, Shijiazhuang, P. R. China
4. School of Civil Engineering, Hunan University, Changsha, P. R. China