1. Chair Professor, Associate Vice-President, Dept. of Civil and Environmental Engineering, Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
2. Graduate Student, Dept. of Civil and Environmental Engineering, Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (corresponding author).
3. Senior Lecturer, Division of Civil Engineering, Univ. of Dundee, Dundee DD1 4HN, U.K.