1. Research Assistant, Dept. of Civil Engineering, Istanbul Technical Univ., Istanbul 34469, Turkey.
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of Maryland, College Park, MD 20742 (corresponding author).
3. Assistant Professor, Dept. of Civil Engineering, Suleyman Demirel Univ., Isparta 32260, Turkey.
4. Professor, Dept. of Civil Engineering, Suleyman Demirel Univ., Isparta 32260, Turkey.