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