1. Postgraduate Student, School of Civil Engineering, Central South Univ., Changsha 410075, China; Engineer, PowerChina ZhongNan Engineering Corporation, Changsha 410014, China (corresponding author).
2. Professor, School of Civil Engineering, Central South Univ., Changsha 410075, China.
3. Postgraduate Student, School of Civil Engineering, Central South Univ., Changsha 410075, China.