1. Post Doctoral Candidate, State Key Laboratory of Hydro Science and Engineering, Univ. of Tsinghua, No. 1 Tsinghua Yuan, Room 340, Xinshuili Building, Beijing 100084, China.
2. Assistant Professor, Construction Engineering and Management Division, Charles Durham School of Architectural Engineering and Construction, Univ. of Nebraska-Lincoln, 113D Nebraska Hall, Lincoln, NE 68588.
3. Professor, State Key Laboratory of Hydro Science and Engineering, Univ. of Tsinghua, No. 1 Tsinghua Yuan, Room 233, Xinshuili Building, Beijing 100084, China.
4. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Michigan, 2350 Hayward St., Room 2340, G.G. Brown Bldg., Ann Arbor, MI 48109 (corresponding author).