1. Ph.D. Student, Dept. of Civil and Environmental Engineering, Auckland Univ., Auckland 1010, New Zealand (corresponding author).
2. Senior Lecturer, Dept. of Civil and Environmental Engineering, Auckland Univ., Auckland 1010, New Zealand.
3. Lecturer, Dept. of Engineering Science, Auckland Univ., Auckland 1010, New Zealand.
4. Assistant Professor, Dept. of Civil and Environmental Engineering, Auckland Univ., Auckland 1010, New Zealand.