1. M.Philosophy Candidate, Dept. of Civil Engineering, The Univ. of Hong Kong, Pokfulam Rd., Hong Kong, China.
2. Professor, Dept. of Civil Engineering, The Univ. of Hong Kong, Pokfulam Rd., Hong Kong, China (corresponding author). E-mail: hrectlg@hkucc.hku.hk
3. Associate Professor, Dept. of Civil Engineering, The Univ. of Hong Kong, Pokfulam Rd., Hong Kong, China.
4. Research Assistant, Dept. of Civil Engineering, The Univ. of Hong Kong, Pokfulam Rd., Hong Kong, China.
5. Professor, Dept. of Civil Engineering, The Univ. of Hong Kong, Pokfulam Rd., Hong Kong, China.