1. Professor and Dean, Faculty of Civil Engineering and Architecture, Zhejiang Univ. of Technology, P. R. China.
2. Senior Lecturer, Dept. of Civil Engineering, Univ. of Dundee, DD1 4HN, U.K. (corresponding author).
3. Postgraduate Student, Faculty of Civil Engineering and Architecture, Zhejiang Univ. of Technology, P. R. China.