1. Professor, School of Civil Engineering, Qingdao Univ. of Technology, Qingdao 266033, China.
2. School of Civil Engineering, Qingdao Univ. of Technology, Qingdao 266033, China.
3. Professor, School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China. (corresponding author).
4. School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China.