1. Postdoctoral Fellow, Dept. of Civil Engineering, Queen’s Univ., Kingston ON, Canada K7L 3N6 (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Amirkabir Univ. of Technology, Tehran, Iran 15875-4413.
3. Professor, Dept. of Civil Engineering and Engineering Mechanics, Univ. of Arizona, Tucson, AZ 85721.