1. Lecturer, Institute of Glass and Metal Structure for Architecture, Key Laboratory of Structural Engineering and Vibration, Ministry of Education, Tsinghua Univ., Beijing 100084 China; formerly, State Key Laboratory for Geomechanics and Deep Underground Engineering, China Univ. of Mining and Technology, Beijing 100083, China (corresponding author).
2. Professor, Institute of Glass and Metal Structure for Architecture, Key Laboratory of Structural Engineering and Vibration of Education Ministry, Tsinghua Univ., Beijing 100084, China.