1. School of Traffic and Transportation, Shijiazhuang Tiedao University, Shijiazhuang, China
2. State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang, China
3. Department of Construction Management, University of Houston, 4730 Calhoun Road No. 300 Houston, Houston, TX 77204-4021, USA