1. Lecturer, Dept. of Civil and Environmental Engineering, Univ. of New South Wales, Kensington, Sydney, NSW 2052, Australia (corresponding author).
2. Associate Professor, Dept. of Civil and Environmental Engineering, National Univ. of Singapore, 1 Engineering Dr. 2, Singapore 117576.
3. Associate Professorial Fellow, Dept. of Civil and Environmental Engineering, National Univ. of Singapore, 1 Engineering Dr. 2, Singapore 117576.
4. Professor, Dept. of Civil and Environmental Engineering, National Univ. of Singapore, 1 Engineering Dr. 2, Singapore 117576.