1. Asistant Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Los Angeles, 5732 E Boelter Hall, Los Angeles, CA 90095 (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Stanford Univ., 439 Panama Mall, Bldg. 540 Room 118, Blume Center, Stanford, CA 94305.
3. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Stanford Univ., 439 Panama Mall, Bldg. 540 Room 118, Blume Center, Stanford, CA 94305.
4. Assistant Professor, Dept. of Civil, Construction and Environmental Engineering, Marquette Univ., Engineering Hall Room 209, 1637 W. Wisconsin Ave., Milwaukee, WI 53233.