1. Assistant Professor in Structural Engineering, Dept. of Civil Engineering, Ilam Univ., Ilam, Iran; formerly, Ph.D. Candidate in Structural Engineering, Dept. of Civil Engineering, Ferdowsi Univ. of Mashhad, Mashhad, Iran (corresponding author).and
2. Professor of Structural Engineering, Dept. of Civil Engineering, Ferdowsi Univ. of Mashhad, Mashhad, Iran.