1. Visiting Research Scholar, Dept. of Civil, Architectural, and Environmental Engineering, Illinois Institute of Technology, Chicago, IL 60616.
2. Professor, Dept. of Civil, Architectural, and Environmental Engineering, Illinois Institute of Technology, Chicago, IL 60616 (corresponding author).
3. Associate Professor, Dept. of Civil Engineering, Middle East Technical Univ., 06531 Ankara, Turkey.
4. Professor, Dept. of Civil Engineering, Middle East Technical Univ., 06531 Ankara, Turkey.