1. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Hong Kong Polytechnic Univ., Kowloon, Hong Kong 999077, China.
2. Professor, Dept. of Civil and Environmental Engineering, Hong Kong Polytechnic Univ., Kowloon, Hong Kong 999077, China (corresponding author).
3. Professor, School of Civil and Transportation Engineering, Guangdong Univ. of Technology, Guangzhou, Guangdong 510000, China.