1. Professor, School of Civil Engineering, Shandong Univ., Jinan 250061, PR China (corresponding author).
2. Ph.D. Candidate, School of Civil Engineering, Shandong Univ., Jinan 250061, PR China.
3. Graduate Student, School of Civil Engineering, Shandong Univ., Jinan 250061, PR China.
4. Lecturer, School of Civil Engineering, Shandong Univ., Jinan 250061, PR China.