1. Professor, Dept. of Civil Engineering, Dalian Univ. of Technology, Dalian 116024, China; Professor, School of Civil Engineering, Shenyang Jianzhu Univ., Shenyang 110168, China.
2. Ph.D. Student, Dept. of Civil Engineering, Dalian Univ. of Technology, Dalian 116024, China; Visiting Student, Rice Univ., Houston, TX 77005.
3. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Rice Univ., Houston, TX 77005.
4. Professor, Dept. of Civil and Environmental Engineering, Rice University, Houston, TX 77005 (corresponding author).