1. Doctor, Dept. of Construction Management, Tsinghua Univ., Haidian District, Beijing 100084, China.
2. Professor, Dept. of Construction Management, Tsinghua Univ., Haidian District, Beijing 100084, China (corresponding author).
3. Professor, Centre for Infrastructure Engineering and Management, Griffith Univ., Gold Coast Campus, QLD 4215, Australia.