1. College of Civil Engineering and Architecture, Zhejiang Univ., Hangzhou 310058, China.
2. School of Civil and Environmental Engineering, Nanyang Technological Univ., Singapore 639798 (corresponding author).
3. Professor, College of Civil Engineering and Architecture, Zhejiang Univ., Hangzhou 310058, China.
4. Associate Professor, College of Civil Engineering and Architecture, Zhejiang Univ., Hangzhou 310058, China.
5. School of Civil and Environmental Engineering, Nanyang Technological Univ., Singapore 639798.