1. Associate Professor, College of Civil Engineering, Qingdao Univ. of Technology, Qingdao 266520, PR China (corresponding author).
2. Graduate Student, College of Civil Engineering, Qingdao Univ. of Technology, Qingdao 266520, PR China.
3. Professor, College of Civil Engineering, Qingdao Univ. of Technology, Qingdao 266520, PR China.
4. Associate Professor, College of Civil Engineering, Qingdao Univ. of Technology, Qingdao 266520, PR China.