1. Professor, Dept. of Civil Engineering, National Cheng Kung Univ., Tainan 701, Taiwan.
2. PhD Candidate., Dept. of Civil Engineering, National Cheng Kung Univ., Tainan 701, Taiwan.
3. Professor, Institute of Structure and Numerical Mechanics, Hannover Univ., Hannover 30167, Germany.
4. Professor, Institute of Transportation Engineering and Planning, Hannover Univ., Hannover 30167, Germany.