1. Associate Professor, College of Civil Engineering, Key Laboratory of Building Safety and Energy Efficiency of Ministry of Education, Hunan Univ., Changsha Hunan 410082, China (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Pennsylvania State Univ., University Park, PA 16802.
3. Professor, College of Civil Engineering, Hunan Univ., Changsha Hunan 410082, China.