1. Associate Professor, School of Civil Engineering, Univ. of Tehran, P.O. Box 11155-4563, 1417613131 Tehran, Iran.
2. Professor and Vice Chancellor for Research, Univ. of Colorado, Boulder, CO 80309-0026 (corresponding author).
3. Professor, School of Civil Engineering, Univ. of Tehran, P.O. Box 11155-4563, 1417613131 Tehran, Iran.
4. Graduate Student, School of Civil Engineering, Univ. of Tehran, P.O. Box 11155-4563, 1417613131 Tehran, Iran.