1. Assistant Professor, College of Architecture and Civil Engineering, Beijing Univ. of Technology, Beijing 100124, P.R. China (corresponding author).
2. Professor, Dept. of Civil, Structural and Environmental Engineering, State Univ. of New York at Buffalo, Buffalo, NY 14260; Professor, Univ. of Advanced Studies, 27100 Pavia, Italy.
3. Professor, Dept. of Civil, Structural and Environmental Engineering, State Univ. of New York at Buffalo, Buffalo, NY 14260.