1. Postdoctoral Fellow, Sonny Astani Dept. of Civil and Environmental Engineering, Univ. of Southern California, 3620 South Vermont Ave., Los Angeles, CA 90089 (corresponding author).
2. Professor, Sonny Astani Dept. of Civil and Environmental Engineering, Univ. of Southern California, 3620 South Vermont Ave., Los Angeles, CA 90089.
3. Research Associate, Dept. of Structural and Geotechnical Engineering, Sapienza Univ. of Rome, 00184 Rome, Italy.
4. Associate Professor, Dept. of Structural and Geotechnical Engineering, Sapienza Univ. of Rome, 00184 Rome, Italy.