1. Lecture, School of Civil and Hydraulic Engineering, Zhengzhou Univ., 100 Kexue Avenue, Henan 450000, China; formerly, Research Student, School of Civil and Environmental Engineering, Nanyang Technological Univ., 50 Nanyang Avenue, Singapore 639798.
2. Professor, School of Civil and Environmental Engineering, Nanyang Technological Univ., 50 Nanyang Avenue, Singapore 639798 (corresponding author).
3. Senior Research Fellow, School of Civil and Environmental Engineering, Nanyang Technological Univ., 50 Nanyang Avenue, Singapore 639798.