1. Professor, Dept. of Civil Engineering, Northwestern Polytechnical Univ., Postal Code: 710072, Xi’an, China (corresponding author).
2. Professor, Dept. of Civil Engineering, Xiamen Univ., Postal Code: 361005, Xiamen, China.
3. Research Assistant, Dept. of Civil Engineering, Northwestern Polytechnical Univ., Postal Code: 710072, Xi’an, China.
4. Senior Professor, Institute of Vibration Engineering, Northwestern Polytechnical Univ., Xi’an, China.