1. Ph.D. Student, Dept. of Civil and Environmental Engineering, Hong Kong Polytechnic Univ., Hung Hom, Kowloon, Hong Kong SAR, P.R. China.
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Hong Kong Polytechnic Univ., Hung Hom, Kowloon, Hong Kong SAR, P.R. China (corresponding author).
3. Professor, Dept. of Civil and Natural Resources Engineering, Univ. of Canterbury, Private Bag 4800, Christchurch, New Zealand.
4. Chair and Professor, Dept. of Civil and Environmental Engineering, Hong Kong Univ. of Science and Technology, Kowloon, Hong Kong SAR, P.R. China.