1. Associate Professor, School of Civil and Environmental Engineering, Nanyang Technological Univ., Nanyang Ave., Singapore 639798. E-mail: ctcgoh@ntu.edu.sg
2. Professor, School of Civil and Environmental Engineering, Cornell Univ., Hollister Hall, Ithaca, NY 14853-3501. E-mail: fhk1@cornell.edu
3. Associate Professor, School of Civil and Environmental Engineering, Nanyang Technological Univ., Nanyang Ave., Singapore 639798. E-mail: ckswong@ntu.edu.sg