1. Assistant Professor, Civil Engineering Dept., Gazi Univ., Ankara 06570, Turkey.
2. Assistant Professor, Dept. of Civil Engineering, Kirikkale Univ., Kirikkale 71450, Turkey (corresponding author).
3. Instructor, Civil Engineering Dept., Gazi Univ., Ankara 06570, Turkey.
4. Engineer, Turkish State Railways General Directorate, Talatpasa Boulevard, Central Station, Ankara 06330, Turkey.