1. Graduate Student, School of Civil Engineering and Architecture, Central South Univ., Changsha, China.
2. Assistant Professor, Dept. of Civil, Architectural, and Environmental Engineering, Missouri Univ. of Science and Technology, 1401 N Pine St., Rolla, MO 65409 (corresponding author).
3. Professor, School of Civil Engineering and Architecture, Central South Univ., Changsha, China.