1. Assistant Professor, Faculty of Aerospace Engineering, K.N. Toosi Univ. of Technology, P.O. Box 16765-3381, Tehran, Islamic Republic of Iran (corresponding author).
2. Former Graduate Student, Dept. of Civil Engineering, Sharif Univ. of Technology, P.O. Box 11365-9313, Tehran, Islamic Republic of Iran.
3. Associate Professor, Dept. of Civil Engineering, Sharif Univ. of Technology, P.O. Box 11365-9313, Tehran, Islamic Republic of Iran.