1. Professor, Dept. of Civil Engineering, Univ. of Technology, P.O. Box 19006, Baghdad, Iraq (corresponding author).
2. Lecturer, Dept. of Civil Engineering, Univ. of Technology, P.O. Box 19006, Baghdad, Iraq.
3. Graduate Student, Dept. Civil Engineering, Univ. of Technology, P.O. Box 19006, Baghdad, Iraq.