1. Ph.D. Candidate, Dept. of Civil Engineering, Univ. of Hong Kong, Pokfulam Rd., Hong Kong.
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Hong Kong Polytechnic Univ., Hung Hom, Hong Kong.
3. Professor, Dept. of Civil Engineering, Univ. of Hong Kong, Pokfulam Rd., Hong Kong (corresponding author).