1. Professor, Dept. of Civil Engineering, Nanjing Univ. of Aeronautics and Astronautics, Nanjing 210016, China (corresponding author).
2. Ph.D. Student, Dept. of Civil Engineering, Nanjing Univ. of Aeronautics and Astronautics, Nanjing 210016, China.
3. Engineer, Guangxi Communications Planning Surveying and Designing Institute, Nanning 530029, China.