1. Professor, Dept. of Civil Engineering, Ferdowsi Univ. of Mashhad, Mashhad, Iran.
2. Ph.D. Candidate in Structural Engineering, Dept. of Civil Engineering, Ferdowsi Univ. of Mashhad, Mashhad, Iran.
3. Assistant Professor, Dept. of Civil Engineering, Univ. of Sistan and Baluchestan, Zahedan, Iran (corresponding author).