1. Professor, Dept. of Civil Engineering, National Cheng Kung Univ., Tainan 70101, Taiwan (corresponding author).
2. PhD Candidate, Dept. of Civil Engineering, National Cheng Kung Univ., Tainan 70101, Taiwan.
3. MS student, Dept. of Civil Engineering, National Cheng Kung Univ., Tainan 70101, Taiwan.