1. MPhil Student, Dept. of Civil Engineering, The Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. E-mail: wnixon@ust.hk
2. Professor, Dept. of Civil Engineering, The Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (corresponding author). E-mail: ghidaoui@ust.hk
3. Visiting Scholar, Dept. of Civil Engineering, The Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; presently, Professor, Dept. of Engineering Mathematics, Riga Technical Univ., Riga 1048, Latvia. E-mail: akoliskins@ust.hk