1. Associate Professor, Dept. of Civil and Structural Engineering, Research Centre for Urban Environmental Technology and Management, The Hong Kong Polytechnic Univ., Hung Hom, Kowloon, Hong Kong (corresponding author).
2. PhD Student, Dept. of Civil and Structural Engineering, The Hong Kong Polytechnic Univ., Hung Hom, Kowloon, Hong Kong; current address: Occupational Safety-Operations Division, Labour Dept., Sham Shui Po Government Office, Kowloon, Hong Kong.