1. College of Engineering, Univ. of Thi-Qar, Iraq; Ph.D. Candidate, School of Civil and Construction Engineering, Oregon State Univ., 101 Kearney Hall, Corvallis, OR 97331.
2. School of Civil and Construction Engineering, Oregon State Univ., 101 Kearney Hall, Corvallis, OR 97331. E-mail john.gamabtese@oregonstate.edu