1. Professor, National Cheng Kung Univ., Dept. of Civil Engineering, Tainan 70101, TW (Corresponding author), e-mail: jishchen@mail.ncku.edu.tw
2. Ph.D. Candidate, National Cheng Kung Univ., Dept. of Civil Engineering, Tainan 70101, TW.
3. Associate Professor, College of Civil Engineering, Hunan University Changsha, Hunan 410082 CN.