1. Lecturer, Dept. of Civil Engineering, Tsinghua Univ., Beijing 100084, China. E-mail: fengpeng@tsinghua.edu.cn
2. Professor, Dept. of Civil Engineering, Tsinghua Univ., Beijing 100084, China. E-mail: ylp@tsinghua.edu.cn
3. Chair Professor of Structural Engineering, Dept. of Civil and Structural Engineering, The Hong Kong Polytechnic Univ., Hong Kong, China. E-mail: cejgteng@polyu.edu.hk