1. Associate Professor, Dept. of Civil Engineering, Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (corresponding author). E-mail: ceyhwang@ust.hk
2. Formerly, Research Student, Dept. of Civil Engineering, Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. E-mail: dapengxu80@hotmail.com
3. Formerly, Research Student, Dept. of Civil Engineering, Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. E-mail: ceronny@gmail.com