1. Ph.D. Candidate, School of Civil Engineering, Southeast Univ., No. 2, Sipailou Rd., Nanjing 210096, P.R. China.
2. Professor, Dept. of Mechanical and Aerospace Engineering, Univ. of Missouri, Columbia, MO 65211.
3. Professor, School of Civil Engineering, Southeast Univ., No. 2, Sipailou Rd., Nanjing 210096, P.R. China (corresponding author).
4. Ph.D. Candidate, Dept. of Mechanical and Aerospace Engineering, Univ. of Missouri, Columbia, MO 65211.