1. Lecturer, Civil Engineering Dept., Faculty of Engineering, British Univ. in Egypt, Building A, Room 204, 11837—P.O. Box 43, El Sherouk City, Cairo, Egypt.
2. Wilson Engineering Professor and Associate Chair, Dept. of Civil, Construction and Environmental Engineering, Iowa State Univ., 376 Town Engineering, Ames, IA 50011-3232 (corresponding author).
3. Assistant Professor, Dept. of Civil and Environmental Engineering, Lehigh University, STEPs Building, Room 326, 1 West Packer Ave., Bethlehem, PA 18015.