1. Professor, Dept. of Civil Engineering, King Saud Univ., P.O. Box 800, Riyadh 11421, Saudi Arabia.
2. Professor, Dept. of Civil Engineering, King Saud Univ., P.O. Box 800, Riyadh 11421, Saudi Arabia (corresponding author).
3. Assistant Professor, Dept. of Civil Engineering, King Saud Univ., P.O. Box 800, Riyadh 11421, Saudi Arabia.