1. Ph.D. Student, Dept. of Civil Engineering, The Univ. of Hong Kong, Pokfulam Rd., LG 201, Composite Building, Hong Kong, China (corresponding author).
2. Professor, Dept. of Civil Engineering, The Univ. of Hong Kong, Pokfulam Rd., LG 201, Composite Building, Hong Kong, China.
3. Adjunct Professor, Dept. of Civil Engineering, The Univ. of Hong Kong, Pokfulam Rd., LG 201, Composite Building, Hong Kong, China.