1. Professor, (Tsinghua-Gammon) Construction Safety Research Center, Dept. of Construction Management, School of Civil Engineering, Tsinghua Univ., Beijing 100084, China (corresponding author).
2. Ph.D. Student, (Tsinghua-Gammon) Construction Safety Research Center, Dept. of Construction Management, School of Civil Engineering, Tsinghua Univ., Beijing 100084, China.
3. (Tsinghua-Gammon) Construction Safety Research Center, Dept. of Construction Management, School of Civil Engineering, Tsinghua Univ., Beijing 100084, China.